KR100387385B1 - Chemical mechanical polishing head having floating wafer retaining ring and wafer carrier with multi-zone polishing pressure control - Google Patents

Abstract

The present invention provides a structure and method for achieving a uniformly polished or planarized substrate, such as a semiconductor wafer, including achieving substantially uniform polishing between the center of the semiconductor wafer and the edge of the wafer. In one aspect, the invention provides a housing, a carrier for mounting a substrate to be polished, a retaining ring surrounding the carrier for holding the substrate, and a first couple for attaching the retaining ring to the carrier such that the retaining ring is movable relative to the carrier. And a second coupling for attaching the carrier to the housing such that the carrier is movable relative to the housing, the housing and the first coupling forming a first pressure chamber to exert a compressive force against the retaining ring. The housing and the second coupling form a second pressure chamber to apply a compressive force against the subcarrier. In one embodiment, the coupling is diaphragm. In yet another embodiment, the present invention includes a single or multi-chambered wafer carrier or subcarrier capable of modifying different polishing pressures across the surface of a wafer or other substrate. Chambered subcarriers allow the selection of polishing pressure between wafer surfaces to achieve greater removal uniformity of material. The present invention also provides a retaining ring having a special edge shape that supports smoothing and pre-compression of the polishing pad to increase polishing uniformity. Polishing methods and semiconductor fabrication are also provided by embodiments of the present invention.

Description

TECHNICAL MECHANICAL POLISHING HEAD HAVING FLOATING WAFER RETAINING RING AND WAFER CARRIER WITH MULTI-ZONE POLISHING PRESSURE CONTROL}

Ultrafine integrated circuits (ICs) require device surfaces to be planarized in the intermetallic connection step. Chemical mechanical polishing (CMP) is a technique adopted for planarization of semiconductor wafer surfaces. Integrated circuit (IC) transistor packing densities have doubled every 18 months for many years, and ongoing efforts have been made to maintain this trend.

There are at least two ways to increase the packing density of transistors on a chip. The first is to increase the device or die size. However, this method is not always the best method as die size increases, die yield per wafer typically decreases. Since the defect density per unit area is a constraining factor, the amount of die without defects per area decreases as the die size increases. Not only is the yield lower, the number of dies that can be stepped on the wafer is also reduced. The second method is to reduce the size of the transistor features. The smaller the transistor, the faster the conversion speed, which is an added benefit. By reducing the transistor size, more transistors and more logic functions or memory bits can be packed in the same device area without increasing the die size.

In the last few years, ultrafine technology has rapidly developed into ultrafine technology. The number of transistors manufactured on each chip has grown tremendously from millions of transistors per chip three years ago to millions of chips per chip today. This density is expected to increase even further in the near future. The current solution to this challenge is to form layers on internal interconnection wiring layers with an insulating (dielectric) thin film in between. The wiring can also be connected vertically via bias to obtain all the electrical paths required by the integrated circuit function.

An inlaid metal line structure using inlaid metal lines embedded in an insulating dielectric layer allows metal interconnect connections to be made on the same plane as well as in the up and down directions through a plasma etch trench and compete in the dielectric layer. In theory, this connection plane can be formed with as many layers on top of each other as desired, as long as each layer is well planarized with a CMP process. The ultimate limit of the interconnection is formed by the connection resistance (R) and the near capacitance (C). The so-called RC constants limit the signal-to-noise ratio and increase power consumption, making the chip nonfunctional. According to industry forecasts, the number of transistors deposited on a chip will be as high as 1 billion and the number of interconnect layers will increase to more than nine layers.

In order to meet the anticipated interconnection requirements, the CMP process and CMP tool performance are advantageously 6 mm so that a large die area can be formed therefrom by providing a polishing head capable of applying a uniform and appropriate force across the entire surface of the wafer during polishing. Excessive and inadequate polishing of less than 3 mm from V is improved to reduce wafer edge exclusion zones and reduce polishing non-uniformity. Current variations in film uniformity after CMP at the wafer edges (2 to 15 mm from the edges) result in lower die yields at the wafer outer edges. The nonuniformity of these edges is due to excessive or insufficient polishing near the wafer edge. By providing a CMP polishing head with the function of adjusting the amount of edge polishing to compensate for excessive polishing or insufficient polishing, a significant yield improvement can be achieved.

An integrated circuit is typically formed on a substrate, especially on a silicon wafer, by successive electrodeposition of one or more layers, the layers of which may be conductive or insulating or semiconducting. Such structures are often referred to as multi-layer metal structures (MIM's) and are important in achieving dense packing of circuit elements on a chip with ever-decreasing design rules.

Flat panel displays, such as those used in notebook computers, personal data assistants (PDAs), mobile phones, and other electronic devices, typically have one or more layers on glass or other transparent substrates to form display elements, such as active or passive LCD circuits. Can be electrodeposited. After each layer is electrodeposited, the layer is etched to remove material from the selected range to create the shape of the circuit. As a series of layers are electrodeposited and etched, the distance between the outer surface and the lower substrate is greatest in the region of the substrate where the least etching occurs and the distance between the outer surface and the lower substrate is smallest in the region where the largest etching occurred. The outer or top surface of the substrate is subsequently less planarized. Even in a single layer, the unplanarized surface will have a uniform profile of vertices and bottoms. Due to the many pattern layers, the difference in height between the vertex and the floor becomes more and more varied, typically up to several microns.

The unplanarized top surface is a problem of the surface photolithography used to make the surface, and each layer may break when electrodeposited onto a surface with excessive height changes. Therefore, it is necessary to periodically planarize the substrate surface to provide a flat layer surface. Planarization involves the removal of uneven outer surfaces and polishing of conductive, semiconductive or insulating materials to form a relatively flat and smooth surface. Following planarization, additional layers can be electrodeposited on the exposed outer surface or etched to form a bias against the exposed subsurface structure to form additional structures including internal connection lines between the structures. have. Generally polishing, more specifically chemical mechanical polishing (CMP) is a known method for surface planarization.

The polishing process is especially designed to achieve surface finish (roughness or smoothness) and flatness (free from large geomorphic forms). Failure to provide minimal finishing and planarization can result in defective substrates, which in turn can lead to defective integrated circuits.

During CMP, a substrate, such as a semiconductor wafer, is typically mounted on a wafer carrier that is part of or attached to a polishing head with a polished exposed surface. The mounted substrate is then positioned relative to a rotating polishing pad disposed on the base of the polishing machine. The polishing pad is directed so that the flat polishing surface of the polishing pad is horizontal to provide a uniform distribution of the polishing slurry and the interaction of the substrate surface at a position facing parallel to the pad. The horizontal orientation of the pad surface (the normal pad surface is perpendicular) allows the wafer to be at least partially in contact with the pad under the influence of gravity and the least amount of mutual interaction in such a way that gravity does not apply non-uniformly between the wafer and the polishing pad. It is also preferred as it allows for action. In addition to the rotation of the pad, the carrier head may rotate to provide additional movement between the substrate and the polishing pad surface. In general, an abrasive slurry comprising abrasive suspended in a liquid and at least one chemical reagent during CMP may be applied to the polishing pad to provide the abrasive mixture and the chemical reaction mixture at the pad substrate interface during CMP. Various polishing pads, polishing slurries and reaction mixtures are known in the art, and combinations thereof can achieve particular finishing and flattening properties. In addition to other factors, the relative speed between the polishing pad and the substrate, the total polishing time, and the pressure applied during polishing affect the flatness and finish of the surface along with the uniformity. In addition, where continuous substrate polishing, or multiple head polishers, is used, all substrates polished during any particular polishing operation are of the same extent to include removal of the same amount of material and provide the same planarization and finish. It is desirable to be polished. CMP and wafer polishing are generally well known in the art and will not be described in further detail here.

U. S. Patent No. 5,205, 082 discloses soluble diaphragm mounting of sub-carriers having numerous advantages over the previous structure and method, and U. S. Patent No. 5,584, 751 describes the use of flexible bladders on retaining rings. Provides control of the downward force, but these patents do not describe any kind of different pressure that modifies the effect of the pressure applied at the interface of the wafer and retaining ring or the edge polishing or planarization effect.

In view of the prior description, there is a need for a chemical mechanical polishing apparatus that optimizes polishing throughput, flatness uniformity and finish while minimizing the risk of contamination or destruction of any substrate.

In view of the preceding description, it provides a substantially uniform pressure between the substrate surfaces being polished, keeps the substrate substantially parallel to the polishing pad during the polishing operation and without causing undesirable polishing abnormalities at the periphery of the substrate. There is a need for a polishing head that holds a substrate in a carrier portion of the polishing head.

The present invention relates to chemical mechanical planarization and polishing of a substrate comprising a silicon surface, a metal film, an oxide film, another type of film on the surface, specifically a polishing head comprising a substrate carrier assembly with a substrate retaining ring, and more specifically The invention relates to a multi-pressure chamber polishing head and a method for polishing a silicon or glass substrate and to chemical mechanical planarization of various oxides, metals or other electrodeposited materials on the surface of the substrate where the substrate carrier and substrate retaining ring are individually controllable.

1 is a schematic diagram illustrating one embodiment of a multiple head polishing / flattening apparatus.

Figure 2 is a schematic diagram illustrating a simple embodiment of a polishing head having two chambers of the present invention.

FIG. 3 is a schematic diagram illustrating a simple embodiment of a polishing head having two chambers of the present invention showing an enlarged manner in which the connecting element (plate) enables movement of the wafer subcarrier and wafer holding ring. FIG.

FIG. 4 is a schematic diagram illustrating a cross-sectional assembly view of an embodiment of a portion of a carousel, a head mounting assembly, a rotating assembly, and a wafer carrier assembly. FIG.

Figure 5 is a schematic diagram showing a more detailed cross-sectional view of one embodiment of the wafer carrier assembly of the present invention.

FIG. 6 is a schematic view showing an exploded assembly view showing elements of the embodiment of the wafer carrier assembly shown in FIG. 5;

FIG. 7 is a schematic cross-sectional view of a portion of an embodiment of the wafer carrier assembly of FIG. 5; FIG.

FIG. 8 is a schematic diagram showing a detailed cross sectional view of another portion of the embodiment of the wafer carrier assembly of FIG. 5; FIG.

Figure 9 is a schematic diagram showing a plan view of one embodiment of a retaining ring of the present invention.

Figure 10 is a schematic diagram showing a cross-sectional view of one embodiment of the retaining ring of the present invention of Figure 9;

Figure 11 is a schematic diagram showing details of an embodiment of the retaining ring of the present invention of Figure 9;

Figure 12 is a schematic diagram showing a perspective view of an embodiment of the retaining ring of the present invention of Figure 9;

FIG. 13 is a schematic representation of a cross-sectional view of a portion of the retaining ring of FIG. 9 showing a transition zone chamfered, especially at the outer radial periphery of the ring; FIG.

Fig. 14 is a schematic diagram showing one embodiment of a retaining ring adapter used in the polishing head of Fig. 5;

Fig. 15 is a schematic diagram showing another view of the retaining ring adapter of Fig. 14;

Fig. 16 is a schematic diagram showing a cross section of the retaining ring adapter of Fig. 14;

Figure 17 is a schematic diagram showing details of how the retaining ring is attached to the retaining ring adapter in cross section.

FIG. 18 is a schematic diagram showing details of cleaning channels and orifices for cleaning abrasive slurry from a ring zone. FIG.

Figure 19 schematically illustrates the virtual retention ring polishing pad interaction of a retention ring with square edges at the ring pad interface.

Figure 20 schematically illustrates the virtual retaining ring polishing pad interaction of a retaining ring with multiple flat chamfered transition zones of the present invention at the ring pad interface.

Figure 21 is a schematic flowchart of one embodiment of a wafer loading process.

Figure 22 is a schematic flowchart of one embodiment of a wafer polishing process.

Figure 23 is a schematic flowchart of one embodiment of a wafer unloading procedure.

Figure 24 is a schematic diagram showing a wafer receiving surface of one embodiment without grooves of the wafer subcarrier of the present invention.

Figure 25 is a schematic diagram showing a wafer receiving surface of one embodiment of a single pressure chamfered machine with a single groove of the wafer subcarrier of the present invention.

FIG. 26 is a schematic diagram showing a partial cross-sectional view of a single pressure chamfered wafer subcarrier with a single groove in FIG. 25; FIG.

Figure 27 is a schematic diagram showing a wafer receiving surface of one embodiment chamfered at three pressures with a single groove in the wafer subcarrier of the present invention.

FIG. 28 is a schematic diagram illustrating a cross-sectional assembly view of an embodiment of a carousel, head mounted assembly, rotational assembly, and wafer carrier assembly portion including a single chamfered wafer subcarrier with a single groove; FIG.

Figure 29 is a schematic diagram showing a more detailed cross-sectional view of one embodiment of the wafer carrier assembly of the present invention of Figure 28;

30 is a schematic cross-sectional view of another portion of an embodiment of the wafer carrier assembly of FIG. 29;

FIG. 31 is a schematic cross-sectional view of a detail of another portion of the embodiment of the wafer carrier assembly of FIG. 29; FIG.

32 is a schematic diagram showing the effect of subcarrier groove pressure on removal rate as a function of position.

The present invention provides a structure and method for forming a uniformly polished or planarized substrate, such as a semiconductor wafer, including achieving substantially uniform polishing between the center of the semiconductor wafer and the edge of the wafer. The chemical mechanical polishing (CMP) head of the present invention has a floating wafer retaining ring with a multi-zone polishing pressure control and a wafer carrier (also referred to as a wafer subcarrier). In one aspect, the invention provides a carrier, a carrier for mounting a substrate to be polished, a retaining ring surrounding the carrier for holding the substrate, a first coupling for attaching the retaining ring to the carrier so that the retaining ring is movable relative to the carrier, the carrier And a first coupling attaching the carrier to the housing such that the carrier is movable relative to the housing, wherein the housing and the first coupling form a first pressure chamber to apply a compressive force to the retaining ring, the housing and The second coupling forms a first pressure chamber to apply a compressive force against the lower carrier. In one embodiment, the coupling is diaphragm.

In another aspect, the present invention provides a structure and method of a substrate (semiconductor wafer) retaining ring for a polishing or planarizing machine, the retaining ring having a lower surface in contact with an external polishing pad during polishing, an outer peripheral surface of the carrier and a carrier An inner surface disposed adjacent the periphery of the substrate mounting surface, and a second plane disposed at the lower outer radial portion of the retaining ring in contact with the pad during polishing and parallel to the plane of the polishing pad and perpendicular to the polishing pad A pad adjusting member defining a shape profile that varies between planes, the inner surface and the carrier mounting surface circumference forming pockets for holding the substrate during polishing. In one embodiment of the invention, the substrate retaining ring is characterized by providing an angle between 15 ° and 25 ° that is not parallel to the nominal plane of the polishing pad. In a different embodiment, the substrate retaining ring is characterized by providing an angle of 20 ° that is not parallel to the nominal plane of the polishing pad.

In another aspect, the present invention further provides a chamfered wafer carrier, wherein the one or more chambers allow modification of the polishing pressure radially from the center of the wafer to the edge of the wafer such that the amount of material removed from the wafer is from the center to the edge. It can be adjusted as a function of the distance to the furnace. One or more chambers are formed in the wafer carrier by forming grooves in the carrier surface to complete the formation of the sealed pressure chamber and placing a flexible film relative to the subcarrier between the subcarrier and the wafer to be polished. Applying a pressurized fluid into the chamber expands the film, compresses the film against the back side of the wafer, and compresses the wafer against the polishing pad with greater force than other portions of the wafer. The chamfered wafer carrier may be used in combination with the aforementioned first pressure chamber that exerts a compressive force on the retaining ring and a second pressure chamber that exerts a compressive force on the carrier.

In one embodiment of the chamfered carrier, a single groove disposed near the outer edge of the carrier is provided to modify the polishing force near the wafer edge to adjust the nonuniformity between the edge and the rest of the wafer. In yet another embodiment, the chamfered carrier is a multiple chamber with multiple grooves in which each groove provides pressure to modify the polishing force in the adjacent region of each groove.

Chamfered carriers can be used with a variety of polishing machines and are not limited to polishing apparatuses or methods having floating retaining rings or floating wafer carriers.

In another aspect, the present invention provides a method of supporting a backside of a wafer with a wafer support subcarrier, applying polishing force to the support subcarrier to compress the front face of the wafer against a polishing pad, and a portion of the subcarrier; A method of planarizing a semiconductor wafer, comprising the step of inhibiting movement of the wafer from a supporting subcarrier during polishing with a retaining ring disposed circumferentially around the wafer. In one embodiment of the method of the present invention, the pad adjustment force is applied irrespective of the polishing force, and in different embodiments, the pad adjustment force is coupled to the polishing force to some extent. In yet another embodiment, the pad adjustment force is applied to the first region of the pad orthogonal to the plane defined by the pad surface using a retaining ring having a chamfered edge profile, the first element perpendicular to the plane and the plane. It is applied to the second zone of the pad in the direction with the second element in parallel. In one embodiment of the method of the invention, the polishing force is adjusted radially from the center of the wafer toward the edge of the wafer by applying different polishing pressures to different spinning zones of the wafer.

In another aspect, the present invention provides a semiconductor wafer polished or planarized according to the method of the present invention.

Figure 1 shows a chemical mechanical polishing or planarization (CMP) tool 101, which comprises a plurality of polishing head assemblies 103 consisting of a head mounting assembly 104 and a substrate (wafer) carrier assembly 106 (shown in Figure 3). It includes a carousel (102) for carrying a carousel. We use the term " polishing " here generally to mean polishing of a substrate 113, including a semiconductor wafer 113 substrate, or planarization when the substrate is a semiconductor wafer on which electronic circuit elements are electrodeposited. Semiconductor wafers are generally thin and somewhat brittle disks with a slight diameter of between 100 mm and 300 mm. Generally 200mm semiconductor wafers are widely used, but the use of 300mm wafers is under development. The design of the present invention is applicable to semiconductor wafers and other substrates up to at least 300 mm in diameter, limiting any significant wafer surface abrasion non-uniformity to a dedicated area of so-called about 2 mm or less at the radial periphery of the semiconductor disk, often with It is limited to an annular zone of about 2 mm or less from the edge.

The base 105 supports the carousel along with the attachment head assembly and supports other components including a bridge 107 that allows the carousel to rise and fall. Each head mounting assembly 104 is installed on the carousel 102, each polishing head assembly 103 is mounted to the head mounting assembly 104 for rotation, and the carousel is mounted on the central carousel shaft 108. The rotational axis 111 of each polishing head assembly 103 is substantially parallel but separate from the carousel rotational axis 108. The CMP tool 101 also includes a motor drive platen 109 that is rotationally mounted about the platen drive shaft 110. The platen 109 holds the polishing pad 135 and is driven to rotate by a platen motor (not shown). A particular embodiment of such a CMP tool is a multiple head design, which means that there are multiple polishing heads for each carousel, but a single head CMP tool is known and the head assembly 103 of the present invention, Retaining ring 166 and polishing method may be used in a multi-head or single head type polishing apparatus.

Also in this particular CMP design, each of the plurality of heads is driven by a single head motor that drives the chain (not shown), which in turn drives each polishing head 103 through the chain and sprocket mechanism, The present invention can be used in embodiments in which each head 103 is rotated by a separate motor. The CMP tool of the present invention also employs a rotary assembly 116 that provides five different gas-liquid channels in communication with pressurized fluids such as air, water, vacuum, etc., between fixed sources outside the head and onto the wafer carrier assembly 106. Located on or in it. In an embodiment of the invention where a chambered subcarrier is employed, an additional rotary union port is included to provide the required pressurized fluid to another chamber.

In operation, the polishing platen 109 to which the polishing pad 135 is attached rotates, the carousel 102 rotates and each head 103 rotates around its own axis. In one embodiment of the CMP tool of the present invention, the carousel axis of rotation is biased by about 1 inch from the platen axis of rotation. The speed at which each component rotates is chosen such that each portion on the wafer moves substantially the same distance at the same average speed as all other locations on the wafer to provide uniform polishing or planarization of the substrate. When the polishing pad is usually compressed to some extent, the speed and manner of interaction between the wafer and the pad where the wafer first contacts the pad is an important determinant of the amount of material removed from the edge of the wafer, and the uniformity of the polished wafer surface.

An abrasive tool having a head assembly equipped with a plurality of carousels is disclosed in US Pat. No. 4,918,870, entitled "Floating Subcarrier of a Wafer Polishing Device," and has a polishing tool with a floating head and a floating retaining ring. Is disclosed in U.S. Patent No. 5,205,082, entitled "Wafer Polisher Head with an Injury Retention Ring," and a rotary joint used in the polisher head is called "Wafer Polishing Device." Rotational Conjugates for Binding Fluids, "US Pat. No. 5,443,416, each of which is described herein by reference.

In one embodiment, the structure and method of the present invention is arranged coaxially with an upper surface 163 inside a polishing apparatus and a lower surface 164 for mounting a substrate (semiconductor wafer) and directly below the substrate around them. An annular retaining ring 166 fitted to the bottom of the subcarrier 160 around the edge of the wafer substrate 113 to keep in contact with the subcarrier 160 and the polishing pad surface itself attached to the platen 109. A head having two chambers with a disc shaped subcarrier with 135 is provided. Holding the wafer directly below the subcarrier is important for uniformity when the subcarrier applies downward polishing onto the back side of the wafer to urge the front side of the wafer against the pad. One chamber (P2) 132 is in fluid communication with the carrier 160 and indirectly applies a downward polishing pressure (or force) on the subcarrier 160 and against the substrate 113 with respect to the polishing pad 135 during polishing. (Called "subcarrier force" or "wafer force"). The second chamber (P1) 131 is in fluid communication with the retaining ring 166 via a retaining ring adapter 168 and applies downward pressure to the substrate 113 against the polishing pad 135 during polishing of the retaining ring 166. (Called "ring force"). The two chambers 131, 132 and their associated pressure / vacuum sources 114, 115 are exerted by the wafer 113 and separately by the retaining ring 166 against the polishing pad surface 135. ) Control is possible.

Although in one embodiment of the present invention the subcarrier force and the ring force are selected separately, the structure may be adapted to provide greater or less coupling between the ring force and the subcarrier force. Strong coupling between the subcarrier and the ring from the independent movement of the subcarrier and the ring by making appropriate selections between the head housing support structure 120 and the subcarrier 160 and between the subcarrier 160 and the ring 166. Independence in the range can be achieved. In one embodiment of the invention, the material and geometrical properties of the connecting elements formed in the manner of the diaphragms 145 and 62 are optimally coupled to achieve uniform polishing (or planarization) across the surface of the semiconductor wafer even at the edges of the substrate. To provide.

Another embodiment of the present invention having a chambered subcarrier will also be described. This chambered subcarrier adds additional pressure that allows for more control of the polishing force as a function of position.

In yet another embodiment, the size and shape of the retaining ring 166 is nonlinear on the polished substrate surface that is associated with the adverse effects associated with the movement of the substrate 113 across the pad 135 from one zone of the pad to another. It is modified compared to conventional retaining ring structures to precompress and adjust the polishing pad 135 in the region near the outer peripheral edge of the substrate 113 so that it does not appear as. The retaining ring 166 of the present invention acts to level the pad 135 at the leading and distal edges of the motion so that the pad is inherently flat and at the same height as the substrate surface before the advancing substrate contacts the new area of the pad. When the contact between the substrate and the pad reaches the end, the pad remains flat and at the same height as the polishing surface of the substrate. In this way, the substrate will always have a flat, precompressed and practically uniform polishing pad surface.

The retaining ring precompresses the polishing pad before moving across the wafer surface. This pre-compresses the entire wafer surface facing the polishing pad by the same amount to evenly remove material across the wafer surface. It is possible to adjust the amount of polishing pad precompression as an independent control of the retaining ring pressure, affecting the amount of material removed from the wafer edges. Computer control with or without feedback, such as the use of the last point of detection means, can assist in achieving some uniformity.

It is first noted that a first simple embodiment of a polishing pad 100 having two chambers of the present invention, shown in FIG. 2, showing how selected aspects of the present invention operate. In particular, the manner in which pressurization to the retaining ring assembly and carrier 160 (including retaining ring adapter 168 and retaining ring 166) is made and controlled is shown and described. Other aspects of the invention will now be described for another slightly more complicated embodiment, including additional choices but with beneficial features.

The turret mounting adapter 121 and the pins 122, 123 or other attachment means may be mounted on a spindle 119 that is rotationally mounted relative to the carousel 102, or the surface of the pad during head and pad rotation in a single head embodiment. It facilitates alignment and attachment or mounting of the housing 120 to other support structures, such as arms that move the head across. Housing 120 provides a support structure for other head components. The second diaphragm 145 provides a second diaphragm from the housing 120 to allow vertical and angular movement of the diaphragm and structure attached thereto (including the carrier 160) with respect to the nominal second diaphragm plane 125. It is mounted to the housing 120 by a spacer ring 131 for separation. (The first and second diaphragms also allow some less horizontal movement with each inclination or each inclination in combination with the vertical translational movement provided to accommodate each variation at the interface between the carrier-pad and the retaining ring-pad interface, This horizontal movement is usually small compared to the vertical movement.)

Spacer ring 131 may be integrally formed in housing 120 in this embodiment and provide the same functionality, but as described in another embodiment (shown in FIG. 5 for example), spacer ring 131 The concentric O-ring gasket, which is advantageously formed from separate pieces and is attached to the housing as a fastener (such as a screw) and ensures its attachment, is air and pressure tight.

The carrier 160 (including retaining ring adapter 168 and retaining ring 166) and retaining ring assembly 165 likewise attach to the first diaphragm 162, which itself attaches to the bottom of the housing 120. do. The carrier 160 and retaining ring 166 can thus be translated vertically and inclined to accommodate non-uniformity at the pad surface and can support planarization of the polishing pad and the pad first retains the ring near the edge of the wafer 113. (166). In general, this type of diaphragm that facilitates movement is called "floating", the carrier and retaining ring are called "injured carrier" and "injured retaining ring", and the head employing these elements is called "injured head". Called. The head of the present invention utilizes "injury" elements, but the structure and method of operation are different from what is known in the art to date.

The flange ring 146 connects the second diaphragm 145 to the top surface 163 of the subcarrier 160, which is itself attached to the first diaphragm 162. The flange ring 146 and the subcarrier 160 are effectively clamped to each other and moved as a unit, but the retaining ring assembly 167 is only mounted on the first diaphragm and freely moved to restrain the movement exerted by the first and second diaphragms. Easy to be The flange ring 146 connects the first diaphragm 162 and the second diaphragm 145. The friction force between the diaphragm and the flange ring and the subcarrier helps to maintain the diaphragm in place and to maintain the tension between the diaphragms. The manner in which the first and second diaphragms allow translational and angular movement of the carrier and retaining ring is also in a state in which the nominal planar shape of each diaphragm 145, 162 is changed to allow for translational and angular degrees of freedom. It is shown by the schematic diagram of FIG. In particular in this direction of movement such enlarged diaphragm bending, shown in the figures, does not occur during polishing, and vertical translational movements usually occur only during wafer loading and unloading operations. In particular, the second diaphragm 145 is to be slightly bent or deformed in the first and second bend zones 172, 173 in the length between the seal ring 131 and the attachment of the flange ring 146, and the first The diaphragm is to be bent or deformed differently in the third, fourth, fifth and sixth bend zones 174, 175, 178, 179 which connect its attachment to the housing 120 and the carrier 160.

In this description, the terms " top " and " bottom " refer to the relative orientation of the structure when the described structure is usually used in its normal operating state as shown in the figures. In the same way, the terms "vertical" and "horizontal" also refer to a direction or motion when the present invention or an embodiment or an element of an embodiment is used in its intended direction. This is suitable for a polishing machine when a wafer polishing machine of the type known by the inventor is provided on a horizontal polishing pad surface for fixing the orientation of other polisher elements.

Next, another slightly more complicated embodiment of the polishing head assembly 103 of the present invention shown in FIG. 4 will be noted. Although the wafer carrier assembly 106 is particularly emphasized, the elements of the head mount assembly 104 of the rotating assembly 116 and the polishing head assembly 103 are also described. Although some structures in the first embodiment of the present invention (shown in FIG. 2) have slightly different structures than those shown in another embodiment (shown in FIG. 4), the elements in some embodiments It can be seen that like reference numerals are attached to clarify the similar functions provided by.

The polishing head assembly 103 usually comprises a spindle 119 forming a spindle axis of rotation 111 and a spindle 119 into a spindle support attached to the bridge 107 in such a way as to allow rotation of the rotary assembly 116 and the spindle. Spindle support means 209 comprising a bearing providing a means for attaching the < RTI ID = 0.0 > These spindle support structures are known in the machine art and are not described in detail herein. The structure within the spindle is shown and described as being attached to the structure and operation of the rotating assembly 116.

Rotational combination 116 provides a means for coupling compressible and incompressible fluids (gas, liquid, vacuum, etc.) between fluid sources, such as vacuum sources, which are stationary and non-rotating and rotatable polishing head wafer carrier assemblies 106. do. The rotary joint is mounted to the non-rotating portion of the polishing head and provides a means for confining and continuously engaging the compressible or incompressible fluid between the non-rotating fluid source and the spatial zone adjacent the outer surface of the rotary spindle axis 119. Although the rotary joint is shown in detail in the embodiment of FIG. 4, it can be seen that the rotary joint can be applied to other embodiments of the present invention.

One or more fluid sources are coupled to the rotating assembly 116 via piping and control valves (not shown). Rotating assembly 116 is formed on an inner surface portion that typically forms a cylindrical reservoir 212, 213, 214 between the inner surface 216 of the rotating assembly 116 and the outer surface 217 of the spindle axis 119. It has a set up area. The seal 218 is provided between the rotary shaft 119 and the non-rotating portion of the rotary joint to prevent leakage between the reservoir and the outer region of the reservoir. Conventional seals known in the mechanical art can be used. Bore or port 201 is also provided below the center of the spindle axis to communicate with the fluid via the rotational coupling.

Spindle shaft 119 has an outer shaft surface and multiple passages, in one embodiment five passages, extending from the top of the shaft to a common bore in the spindle shaft. Due to the particular cross sectional view of FIG. 4, only three of the five passages can be seen in the figure. Vacuum or other compressible or incompressible fluid is communicated from each bore to the position where the fluid is needed via a coupling or tubing in the wafer carrier assembly 106. The exact location or presence of the coupling is an implementation item and is not critical to the spirit of the invention except as described later. These listed structures provide a means for confining and continuously coupling one or more compressive fluids between an area injured on an outer surface of the axis of rotation and an enclosed chamber, although other means may be used. Rotating assemblies that provide fewer channels than in this particular embodiment of the present invention are described herein by reference and US Pat. No. 5,443,416, entitled "Rotating Joints for Joining Fluid in Wafer Polishing Devices." It is described in the issue.

The wafer carrier assembly 106 will now be described with reference to FIG. 5 showing a cross sectional view through the " section A-A " of the wafer carrier assembly 106, and to FIG. 6 showing an exploded assembly diagram of the wafer carrier assembly 106. FIG. It can be seen from FIG. 6 that the wafer carrier assembly 106 has a high symmetry around the central axis, but not all elements are symmetrical with respect to the location of the detailed features such as holes, orifices, fixtures, notches, and the like. Rather than describing the wafer carrier assembly 106 for any single diagram, Figure 5 (which is a side view through section AA), Figure 6 (which is an exploded assembly drawing), and Figure 7 (right enlarged cross-sectional view of Figure 5). And the combination of FIG. 8 (which is an enlarged cross-sectional view on the left side of FIG. 5), which shows the components from slightly different perspectives and clarifies the structure and operation of each element.

The chemical mechanical polishing as well as the properties of the polishing pad, slurry and wafer composition are well known and will not be described in any detail except as necessary for the understanding of the present invention.

Functionally, the wafer carrier assembly 106 provides all the structures needed to mount and hold a substrate 130, such as a semiconductor wafer, during a polishing operation. (It should be noted that the present invention can be applied to polishing substrates other than semiconductor wafers.) The carrier assembly 106 is a wafer through a hole or opening 147 to hold the wafer for the time between wafer loading and initial polishing. A vacuum is provided to one bottom surface 164 of the subcarrier. It also maintains the wafer in the pocket to reduce or eliminate polishing non-uniformity near the edges on the wafer and provides downward polishing pressure on the wafer through the wafer subcarrier to interact with the polishing pad and a separate downward pressure on the retaining ring. To provide. The wafer carrier assembly 106 also provides a source of fluid such as deionized water (DI water), compressed air, and vacuum in some chambers and orifices, the surfaces of which are described in more detail below. The wafer carrier assembly is particularly important in that it provides a diaphragm mounted subcarrier and a retaining ring assembly that itself includes a retaining ring adapter and a retaining ring. The diaphragm mounting elements and their structural and functional relationship with other elements and chambers provide some advantageous features of the present invention.

The upper housing 120 is mounted to the mounting adapter 121 via four socket head screws, which in turn are mounted to the bottom of the head mounting assembly 104 via screws and by the first and second pins 122, 123. Position is set. Upper housing 120 provides a stabilizing member to which other elements of the wafer carrier assembly can be mounted thereon as described herein. The housing seal ring 129 is usually a circular element that serves to separate the first pressure chamber P1 131 from the second pressure chamber P2 132. The pair of o-rings 137, 139 is provided with a housing seal ring that provides a leak proof fluid and pressure seal between the housing seal ring 129 and the upper housing 120 when attached to the inner surface of the upper housing 120. Disposed in a separate channel machined into the top surface of 129. The pressure in the first pressure chamber 131 is operated to affect the interaction of the down pressure on the retaining ring assembly 134 with the polishing pad 135. The pressure in the second pressure chamber 132 is operated to affect the downward working pressure on the subcarrier 136, which in turn provides the polishing pressure applied between the bottom surface of the wafer 138 and the polishing pad 135. Optionally, a polymer or other insert 161 may be used between the bottom surface 164 of the subcarrier 106 in the top or back side of the wafer 138. The internal structure within the wafer carrier assembly 106 provides independence between pressure and movement of the retaining ring assembly 134 and the subcarrier 136.

One or more fixtures 141 are provided to communicate compressed air from a location or source 114 to the chamber outside of the first pressure chamber 131 and the one or more fixtures 142 may operate in a similar manner to the second external source or location ( 115 is provided to communicate compressed air from the second pressure chamber 132. These fixtures 141, 142 are connected to the rotary coupling 116 with the channels in the head mounting assembly 104 via appropriate piping, and provide a predetermined pressure level through an appropriate control circuit. The manner and order in which pressure, vacuum and fluid are communicated will be described later.

The locking ring 144 is mounted to the lower surface of the housing seal ring 129 via 18 screws and inserts the second diaphragm 145 into the housing seal ring 129 by interposing or clamping the second diaphragm between the two structures. And between the locking ring 144. Both the housing seal ring 129 and the locking ring 144 as well as the portion of the second diaphragm 145 clamped between the housing seal ring 129 and the locking ring 144 are in a fixed position with respect to the upper housing 120. maintain. A portion of the second diaphragm 145 lying radially inside of the inner diameter of the housing seal ring 129 is upper on the lower surface by the upper surface of the inner flange ring 146 and upper by the lower surface of the inner stop ring 148. It is clamped on the face. The inner flange ring and the inner stop ring are attached by fastening means such as socket head cap screw 149.

The portions of the housing seal ring 129, the locking ring 144 and the second diaphragm 145 clamped between these two structures maintain a fixed position relative to the surface of the upper housing 120, but the second diaphragm ( The inner flange ring 146 and the inner stop ring 148 suspended from 145 move upward and downward relative to the polishing pad 135 and the upper housing 120, and to the polishing pad 135 and the upper housing 120. Each direction or tilt change is at least somewhat free. Due to the ability of such structures to move vertically upward and to change their respective directions downward, structures attached thereto, such as subcarrier 136, wafer 138, and retaining ring assembly 134, may be attached to the surface of the polishing pad 134. You will be able to injure yourself.

The second diaphragm thickness Td as well as the physical gap between the first vertical edge 151 of the inner flange ring 146 and the second vertical surface 152 of the locking pin 144 adjacent the first vertical edge 151. The second diaphragm as well as the distance between the clamping portion of the second diaphragm 145 between the housing seal ring and the locking ring to the clamping portion of the second diaphragm 145 between the inner flange ring 146 and the inner stop ring 148. The properties of the material from which 145 is made will affect the vertical momentum and the tilt or angular momentum. This property provides an effective spring constant of the diaphragm. Although it is described herein that the first and second diaphragms are generally formed from the same material in embodiments of the present invention, other materials may be used.

In one embodiment of the invention that is suitable for a 200 millimeter (mm) semiconductor wafer to be mounted, the diaphragm is made from 0.05 inch thick pores with a Nilo material made by INTERTEX. This material has internal fibers that provide strength and rigidity while also providing the desired elasticity. Those skilled in the art will appreciate that different sizes and materials may be used to achieve the same or similar operation based on the description provided herein. For example, a thin metal film can give sufficient elasticity to be able to deflect vertically in response to the pressure applied to it, and can provide sufficient angular motion to keep contact with the pad during polishing. As long as there is a thin metal sheet or film can be used as the second diaphragm 145. In some instances, the flat sheet material does not have sufficient resilience on its own and therefrom, but by forming the sheet in a suitable manner with corrugated annular grooves, pleats or the like, the metal connecting element is described herein. Alternative structures can be provided. Composite materials can also be used to provide the desired properties. The relationship between the clamping and non-clamping portions of the second diaphragm 145 and the distance between the locking 144 and the inner flange ring 146 is shown in more detail in FIGS. 7 and 8.

In addition to the inner flange ring 146 clamped to the second diaphragm 145, the inner stop ring 148 is also excessively upward of the inner stop ring 148, the diaphragm 145, the inner flange ring 146 and the structure attached thereto. A motion limit stop function is provided to prevent the motion from excessively upward movement into the recess 152 in the upper housing 120. In one embodiment of the present invention, the structure that is attached to the inner stop ring 148 has a diaphragm before the stop contact surface 153 of the inner stop ring 148 contacts the opposite contact surface 154 of the housing seal ring 131. 145 may be moved upwards by about 0.125 inches from the nominal position to be planar and downwards by about 0.10 inches for the entire travel distance of about 0.25 inches. During actual polishing, only this upward and downward (vertically) range of motion is needed. The remainder is used to extend the carrier over the bottom edge of the retaining ring during the loading and unloading operation of the wafer (substrate). The ability to project the edge of the subcarrier 160 beyond the bottom edge of the impingement ring is convenient and facilitates loading and unloading operations.

The vertical range of motion is limited by the mechanical stop rather than the diaphragm material. The use of a stopper prevents unnecessary forces on the diaphragm when the carrier wafer is not in contact with the pad, such as during loading and unloading operations and during maintenance, or when the diaphragm is turned off to extend or twist in the long term. The structure of the present invention also provides a carrier head assembly having a pocket depth with a wafer that automatically adjusts itself.

The subcarrier 160 is mounted to the lower surface of the inner flange ring 146 by a mounting method such as socket head cap screw 157 and thereby (mechanical stop on the stop ring when in the lower limit position of the vertical range of motion). Subcarrier 160 is effectively suspended from the second diaphragm 145, which is held by and prevented from excessively upward movement by the second set of mechanical stops and provides the vertical and angular motions already described for the subcarrier. Done. The first diaphragm 162 is clamped between the peripheral rings of the inner flange ring 146 and is attached to the top surface 163 of the subcarrier 160 by socket head cap screws 157 near the subcarrier edge. In at least one embodiment, the subcarrier 160 formed of another nonporous ceramic material is fitted to the stainless steel insert to receive the threaded portion of the screw 157.

An aspect of the retaining ring assembly 134 will now be described before describing important aspects of the interaction between the retaining ring 134, the subcarrier 136 and the first diaphragm 162. Retaining ring assembly 167 includes retaining ring 166 and retaining ring adapter 168. In one embodiment, retaining ring 166 is formed from the trade name Techtron PPS (polyphenylene sulfide). The retaining ring adapter 168 is mounted to the bottom surface 170 of the outer stop ring 171 and the first diaphragm 162 is clamped therebetween. Retaining ring 166 is formed of techtron material and is attached to retaining ring adapter 168 via a socket head screw via a first diaphragm and an outer stop ring. The chamfer 180 of retaining ring 166 at its outer diameter advantageously reduces the edge polishing non-linear region that typically occurs when using conventional polishing tools. The outer stop ring 169 is coaxially mounted with respect to the inner flange ring 146, but both the outer stop ring 169 and the retaining ring assembly 134 are firstly located at a greater radial distance from the center of the wafer carrier assembly 106. It is not mounted to the inner flange ring 146 except to be joined to each other by the diaphragm 162 and not to any other element except the retaining ring adapter 168 and the first diaphragm 162. The characteristics of this coupling are important for the provision of mechanical properties that contribute to the polishing gain provided by the present invention. The structures that contribute to this coupling are shown in greater detail and in greater detail in FIGS. 7 and 8.

The structure and overall operation of the first diaphragm 162 and the manner in which the diaphragm is attached to the subcarrier 160 and retaining ring assembly 134 will now be described. In addition, details of the wafer carrier assembly that contribute to the ability to reduce non-linear areas, often referred to as "ringing" at the edges of the polished wafer, will be described. First, the first diaphragm 162 is a coupling between the pressure applied to the subcarrier 160 and a separate ?? force applied to the retaining ring 166, and the movement of the subcarrier and the retaining ring as a result of these pressures; It can be seen that the reaction upward force of the polishing pad 135 must have toughness with elasticity to be within an appropriate range. This means that the movement of the retaining ring and the subcarrier must be independent within the range of motion, but at the same time in some embodiments it provides some coupling between the movement of both the retaining ring and the subcarrier.

The predetermined degree of coupling is (i) the third clamping zone 182 (between the subcarrier 160 and the inner flange ring 146) and the fourth (between the retaining ring adapter 168 and the outer stop ring 169). Adjusting the span of the first diaphragm 162 between the clamping zones 183, (ii) adjusting the thickness and material properties of the first diaphragm 162, and (iii) interacting with the diaphragm 162 in the span region. Adjustment of the surface geometry, (iv) adjustment of the distance between the two vertical surfaces 185 of the subcarrier 160, the vertical surface 186 of the retaining ring adapter 168, and the vertical surface 187 of the retaining ring 166, and (v) between the surface 188 of the retaining ring adapter 168 and the vertical surface 190 of the lower housing 122 and between the vertical surface 189 of the retaining ring 166 and the same vertical surface 190 of the lower housing 122. It is influenced by several factors including the adjustment of distance or gap. By adjusting these factors both vertical and angular movements occur, but without excessive movement can cause binding of the retaining ring to the subcarrier 160 or the lower housing 122.

In one embodiment of the invention, the distance d1 between the subcarrier and the retaining ring adapter is 0.050 inches, the distance d2 between the subcarrier and the retaining ring is 0.010 inches, and the distance d3 between the retaining ring adapter and the lower housing. Is about 0.5 inches and the distance d4 between the retaining ring and the lower housing is 0.015 inches. These relationships are shown in FIG. Of course, one of ordinary skill in the art will recognize that these dimensions are exemplary and that other dimensions and relationships may be provided to achieve the same function. In particular, each of these dimensions can be modified by up to about 30% or more and one can still expect to provide equivalent work if not optimal. The greater variation in dimensional tolerances results in a partial optimization device that can be used.

7 and 8 the outer radial portion of the subcarrier 160 adjacent to the connection of the first diaphragm 162 also forms an actual right angle with the vertical plane 185, but both vertical planes of the retaining ring adapter. It can be seen that the inclined portion at the opposite edge 194. Retaining corners with approximately square (90 °) corners has been found to be beneficial in preventing binding of subcarriers with retaining rings or retaining ring adapters. It has also been found that providing a slight inclination or chamfer 194 on the adjacent surface of the retaining ring adapter 168 is beneficial for the mobility of the retaining ring without binding, but if the incline is too large then it is somewhat undesirable. It was observed that no binding could occur. While this combination has been found to have some advantages, one of ordinary skill in the art will recognize that other variations facilitate smooth motion control without binding of adjacent elements.

Another advantage of the present invention has been realized by providing a particular type of profile at the exterior or radial surface 195 of the retaining ring 166, referred to as the transition zone 206. Typically, the retaining ring, if provided at least, provides a desirable surface profile that slides against a mating surface, such as an equivalent surface of the inner radiating wall surface of the lower housing 122, or the importance of the edge profile is not considered and is defective. Since no vertical profile is used, it is actually formed as a vertical outer wall. In one embodiment of the invention, retaining ring 166 has the profile form shown in FIGS. 9-13 showing various aspects of the retaining ring at different levels of detail. FIG. 10 is a cross-sectional view of the embodiment of the retaining ring of FIG. 9, FIG. 11 is a detail view and FIG. 12 is a perspective view of the retaining ring. Figure 13 is a schematic diagram showing a cross-sectional view of a portion of a retaining ring, particularly showing the transition zone chamfered at the outer radial periphery of the ring.

In the case of this embodiment of the retaining ring, the lower surface 201 in contact with the polishing pad 135 during polishing is provided with a gap to remove the binding, but the lower housing 122 in operation over the two inclined surfaces 202, 203. ) Moves to the actual vertical plane 204 opposite the actual parallel vertical plane 189 on. Surface 204 is substantially perpendicular to upper retaining ring surface 205 and upper surface 205 is substantially parallel to lower surface 201. Preferably, during manufacture of the wafer carrier assembly, the assembly fixture is used to maintain alignment of the component parts and to set the gap and other spacing between the ring 166 and the subcarrier 160 and the housings 120 and 122. do.

It has been found empirically that this transition zone 206 actually improves the quality of the edges of the polished wafer by eliminating nonlinearities in polishing. Such nonlinearity usually manifests as troughs or vertices (waveforms or rings) within about 3 to 5 mm or more from the outer edge of the wafer. Without gaining the theory, the properties of this transition zone 206 not only keep the wafer in the pocket against the subcarrier during the polishing operation, but also directly to the portion of the pad that contacts the wafer when the retaining ring is also at the leading edge of the motion. It is considered important because it acts to compress or knit the preceding polishing pad and to expand the area where the pad is planarized over when a portion of the retaining ring is the leading edge of the wafer. Indeed, the retaining ring may be in any state that keeps the surface flush with the wafer to warp or deform the polishing pad 135, the accumulation of abrasive slurry at the leading edge, or other nonlinear or non-uniform effects outside the retaining ring. It occurs at or below it and not at or near the edge of the wafer.

The specific retaining ring geometry in the transition zone 206, i.e. the optimal angles in the case of transition zones α1 = 20 °, α2 = 20 ° and α3 = 90 °, results in the design of the multi-head polishing device and the polishing pad 135. A combination, a polishing pad rotational speed of about 30 revolutions per minute (RPM), a wafer carrier assembly rotational speed of about 26 RPM, a 200 mm diameter silicon wafer, and, for example, a polishing pressure of about 5 pounds per square inch (5 psi), and It has been found to be optimal for retaining rings of techtron material. In such multi-head carousel-based polishers, the effective linear velocity of the ring between the surface of the pad is about 80 to 200 feet per minute. The polishing pressure can be varied over a larger range to achieve the desired polishing effect. In one example, the pressure on the subcarrier may be in the range of about 1.5 to 10 psi while the pressure on the retaining ring may be the same as the pressure on the subcarrier and the pressure on the retaining ring is usually in the range of about 1.5 to 9 psi. Although the present invention is not limited to any particular polishing pad form, one polishing pad useful for chemical mechanical polishing or planarization with the head of the present invention is registered under the trademark Rodel CR IC1400-A4 (Rodel Part No. P05695, product type). IC1400, K-GRV, PSA). This particular pad 135 has a nominal diameter of 35.75 inches (all measured by the RM-10-27-95 inspection method), a thickness range between about 2.5 to 2.8 mm, and a deviation between about 0.02 to 0.18 mm, Compressibility between about 0.7 and 6.6% and recoil of about 46%. Another alternative is the Padel CR IC1400-A4, P / V / SUBA type pad (Rodel Part No. P06342).

The retaining ring has a thickness of about 0.25 inches with a 20 degree inclined portion 202 extending upwards about 0.034 inches from the bottom surface of the ring and the vertical portion 203 about 0.060 before encountering the second rectangular segment 203. Stretched inches. These sample sizes are shown in the figure. Because of this particular combination of variables, it has been empirically determined that these angles are somewhat sensitive to plus or minus 2 degrees for optimal work, but a larger range, for example at least plus or minus 4 degrees for a given angle, has been determined. Provide useful results. However, the subject providing the transition zone for the retaining ring is an important determinant of achieving uniform polishing, particularly at the edges of the wafer, while the actual shape of this transition zone depends on the particular physical parameters associated with the polishing operation. It will be noted that it will require harmony. For example, the use of star polishing pads (particularly if of different thickness, compensable object, elasticity, or coefficient of friction), star platen rotation rate, star carousel rotation rate, star separation rate Alternative transition zone planes may be proposed for optimum results up to wafer carrier combination rotation speed and to separate polishing slurries. Fortunately, once a CMP abrasive tool is used, these parameters are usually unchanged or can be adapted according to the basic quality control procedures performed during CMP tool preparation.

For a single head grinder (eg, including a grinder of the type in which the polishing pad rotates, the head rotates and the head vibrates back and forth in a linear reciprocating motion), the same parameters are expected to be suitable, but across the pad The effective linear speed of the major edge of the retaining ring is a suitable parameter rather than a combination of polishing pad speed, carousel speed and head speed.

In one embodiment of the invention suitable for the original retaining ring structure, the 20 degree transition angle of the retaining ring yarn provides a practical advantage over conventional retaining edge edge designs of square corners. The transition zone can pre-squeeze and smooth the pad before the wafer enters the area, thereby removing ringing marks on the edge of the wafer.

Therefore, in the case of the structure shown in Fig. 13, in particular the combination chamfered at a 20 degree angle shows excellent results for the described system, but other modified transition zone structures that vary between parallel and vertical are, for example, radially shaped. Optimal for other CMP polisher forms, including transition forms, elliptical forms, linear transition zones with only one chamfer between surfaces 201 and 209, and forms providing different angles and more surfaces in the transition zones. Can be

We will now briefly describe additional details of retaining ring adapter 168 in relation to FIGS. FIG. 14 is a tabular technique showing an embodiment of the original retaining ring adapter used in the polishing head of FIG. 5, and FIG. 15 shows another view of the same ring. Figure 16 shows a cross-sectional view of the retaining ring adapter of Figure 14, and Figure 17 shows a detailed view of a cross section of the method for attaching the retaining ring to the retaining ring adapter. FIG. 18 shows additional details of the cleaning channels and orifices for removing abrasive slurry from the ring zone.

In connection with these figures, retaining ring adapter 168 is typically formed of metal to provide suitable strength, stability of size, features of the structure within the head, and the like. On the other hand, the retaining ring must continually float on the surface of the polishing pad during the polishing operation and be compatible with the environment, and must not deposit material on the pad that may harm the polishing operation. Such materials are typically soft materials, such as the techron material used in one embodiment of the present invention. Retaining ring is also a wear item. Therefore, in theory, it would be beneficial to provide separate retaining ring adapters and replaceable retaining rings, even though they are not optimal features but may be complete structures that can be used for both functions.

The retaining ring adapter 168 provides a method of attaching the retaining ring 166 to the main diaphragm 162, in addition to (i) the subcarrier 160 and retaining ring 166 (and retaining ring adapter 168). )) Or (ii) a plurality of T-shaped channels or orifices for removing slurry that can collect between retaining ring 166 (and retaining ring adapter 168) and lower housing 122. In the embodiment of the invention shown in Figures 14-18, five such T-shaped (or vice versa) channels are provided to settle at substantially equal intervals around the circumference of the retaining ring adapter 168. A first vertically downwardly extending hole (177 approximately 0.115 inch in diameter) is provided with a surface 186 proximate the subcarrier surface 185 and an inner surface of the lower housing 122 and the retaining ring adapter 168. To the top surface of the retaining ring adapter 168 to intersect a second horizontally extending bore 176 (approximately 0.1 inch diameter) between the area between the outer wireless portion and the subsequent passageway surface 196 in space. From about 0.125 inches down.

By passing the non-ionized water through the first orifice, the space between the subcarrier and the retaining ring removes the slurry, and the water passes through the second orifice, whereby the area between the retaining ring and the lower housing is said to be free of slurry. maintain. Separate channels and orifices may alternatively be provided separately in the ring housing area and the ring subcarrier area, but there is no particular advantage with such a structure. The release pressure and amount must be tailored to produce a suitable removal activity. Details of this orifice are also shown in FIG. The method of delivering fluid from the external water source to the fixture 197 via the rotating assembly 116 is implementation detail and not shown.

In one embodiment of the invention, five 0.100 inch T-shaped holes or channels are provided for head cleaning. High pressure non-ionized water is allowed to pass through these holes to remove and clean accumulated slurry. A 0.45 inch wide area by 0.20 inch step on the top surface of the retaining ring adapter 168 provides sufficient physical space to clean the water flow to remove slurry deposits, and in relation to both the carrier and the housing, The result is an unrestricted exercise. Free movement of the subcarrier and retaining ring is important to maintain uniform polishing at the edges of the wafer. The square edge of the subcarrier allows the retaining ring to move separately from the subcarrier and to maintain a constant vertical distance.

Subcarrier 160 also has additional features. In one embodiment, subcarrier 160 is a solid, round, nonporous ceramic disk having a diameter of about 8 inches (7.85 inches in one particular embodiment) in the case of deformation of an abrasive tool applied to a 200 mm wafer. (In one embodiment intended to polish or planarize a 300 mm semiconductor wafer, the subcarrier has a diameter of about 12 inches (300 mm).) The subcarrier has square corners on the top and bottom surfaces and the bottom surface is planarized. And overlap for smoothness. Six vacuum holes 147 (0.040 inch diameter) are provided in the subcarrier passageway on the lower surface 164 of the subcarrier on which the subcarrier mounts the back side of the wafer. These holes are in fluid communication with a single bore 184 at the upper center of the subcarrier. Fit male thread 10-32 NPT one-touch connectors are provided on the upper surface of the subcarrier for connection to the piping via rotary unions and to external sources of vacuum, compressed air or water.

The holes are formed by boring the first hole 184 into the top surface of the subcarrier 160, and then radially inward boring six holes from the cylindrical edge of the subcarrier to the central bore hole 184. The six holes are then bored upwards from the subcarrier surface from the bottom surface of the subcarrier until they intersect the six radially extending holes or bores 191 to complete the connection to the central bore hole 184. The portion of the radially extending holes between the six vertically extending holes and the cylindrical edge on the subcarrier is then filled with a stainless steel plug 181 or other means to prevent leakage of air, vacuum, pressure or water. These holes and channels are used to supply a vacuum to the back side of the wafer to retain the wafer on the subcarrier and to provide compressed air or water or a combination thereof to press the wafer away from the subcarrier during the wafer unloading operation. do.

We will now explain why the retaining ring of the present invention performs the adjustment of the pad 135 well. Figure 19 is a schematic diagram illustrating virtual retention ring polishing pad interaction for a retention ring with square edges at the ring-pad interface. In this example, the square edge of the pad compresses the pad and curves upward when the edge of the ring compresses forward downward. The pads experience the impact of the ring and the vibrational development in the pads extending into the area under the wafer. On the other hand, in the case of a retaining ring having the multi-planar chamfered transition zone of the present invention at the ring-pad interface with the retaining ring of the present invention shown, the interaction of the retaining ring and the polishing pad results in less vibration in the pad. Or a less magnitude of vibration that dissipates before reaching the wafer surface. The beneficial effect is also partially achieved by applying downward pressure to only a partial component of the retaining ring at the outer radial edge of the ring, and by gradually increasing the pressure to a smaller radius. In practice, the transition zone guides the pad under the ring and increases pressure as the pad passes, reducing the impact of the ring on the pad and applying force more gradually.

Three embodiments of a head wafer loading / unloading and polishing process related to the structure and method of the present invention will now be described. 21 shows a flowchart of the head wafer loading process 501. It can be seen that this process includes several steps performed in the preferred embodiment of the present invention, but it is understood that not all of the described steps are essential steps and that some optimal steps are provided for optimal results throughout the process. .

Robotic wafer handling devices are commonly used, especially in the semiconductor industry, where processes are performed in clean room environments. In this relationship, the head loading module (HLM) and the head unloading module (HULM) are provided to provide the wafer to the polishing CMP tool and to receive the wafer from the CMP tool when polishing is complete. Even if the HLM and HULM are the same robot, two separate machines can be used, one providing a clean dry wafer and the other receiving a wet wafer coated with an abrasive slurry. HLMs and HULMs generally include a fixed portion and a segmented arm portion that includes rotational capability and moves the robot hand, paddle, or other wafer holding means in three dimensions. The robot hand is moved under computer control to move the wafer from the storage location to the CMP tool and returned to water or another storage location after polishing or planarization is complete. The following process is called the manner in which the HLM or HULM interacts with the CMP tool and more specifically with the elements of the wafer carrier assembly.

First, loading of the wafer into the head is started (step 502). This includes the controlled movement of the HLM robot arm from the "circle" position to the "head" position (step 503). The original position of the HLM is where the robot loading arm is outside the carousel and far from the head. The head position is the position of the robot arm where the robot arm extends under the polishing head just below the carousel and provides the wafer to the mounting head. In step 504, the head subcarrier extends (downward) into chamber P2 132 under the influence of pressure so that the carrier surface extends below the lower edge of the retaining ring, and the robot arm then presses the wafer against the carrier surface. Extend upward Springs are provided to avoid rough contact that could damage the wafer. Next, the HLM nozzle selectively sprays DI water onto the head and the head flush valve is actuated to open the valve for DI water passing through the valve (step 505). The HLM is then returned to the "raw" position and loaded onto the wafer (step 506). The HLM then proceeds to the "head" position (step 507). Next, the computer checks the head vacuum switch to confirm operation (step 508). The acting head vacuum switch is important because it ensures that the vacuum acts so that the head can pick up the wafer from the robot's extension arm. If the head vacuum switch is deactivated, the head cleaning cycle ensures that the head subcarrier vacuum is activated (step 509) to repeat the start in step 502 until the working head vacuum switch is verified and ready to accept the wafer. ).

The HLM moves to the head wafer loading position (step 510) and the head subcarrier picks up the wafer from the HLM (step 511). Next, at the rear side of the wafer, it is determined whether the wafer is picked up by the subcarrier applying the niche, and if the wafer is on the subcarrier, the head subcarrier is shrunk with the attached wafer (step 512). The wafer polishing process then begins (step 513). On the other hand, if the wafer is not on the subcarrier, the HLM moves down and then is returned upward for loading again onto the head (step 514) and steps 510 to 511 until it is confirmed that the wafer is on the subcarrier. Repeat.

The wafer polishing process will now be described with reference to FIG. 22, which shows a schematic flowchart of the polishing process (step 521). Wafer polishing is initiated after the wafer is loaded onto the subcarrier as described above (step 522). The polishing head attached to the turret and carousel assembly is moved downward to the polishing position so that the wafer is placed in contact with the polishing pad attached to the platen and the head wafer backside vacuum that assists attaching the wafer to the subcarrier is deactivated. (Step 523). The vacuum valve then closes and closes just before polishing. The valve is then opened, checked to confirm wafer presence prior to polishing and then closed again (step 524). In this stage of the process, the vacuum switch should be shut down normally, and when the vacuum switch is turned on, an alarm will be generated in the form of an audible, visual or other indicator (step 525). When the vacuum switch is turned off, the process proceeds by applying air pressure to each of the two chambers of the head chamber P1 and the chamber P2 (steps 526 and 527). The air or other fluid pressure applied to the chamber P1 controls the pressure or force on the subcarrier so that the polishing pressure is applied on the front side of the wafer relative to the opposite side of the polishing pad (step 526). The air or fluid pressure applied to the chamber P2 controls the pressure applied to the retaining ring, which pressure maintains the wafer in the pocket formed by the retaining ring, polishes the wafer and removes the nonlinear polishing effect at the edge of the wafer. In an optimal state, the polishing pad is placed immediately near all edges of the wafer (step 527).

In an embodiment of the present invention which includes the chamfered wafer subcarrier of the present invention, the air pressure is controlled by the chamber P3 (multi-chambered to each other subcarrier chamber) for further control of the pressure or force on the edge of the subcarrier. Form) and the resulting polishing pressure is applied on the periphery of the front face of the wafer with respect to the opposing face of the polishing pad. Likewise, in a multi-chambered embodiment with multiple grooves, air pressure is applied to each subcarrier chamber to control the pressure or force on each zone of the subcarrier so that the polishing pressure is applied to the wafer against the opposite side of the polishing pad. Is applied within the region of the front face (usually an annular region).

Returning to the discussion of the unchambered subcarriers, once the proper pressure in the two chambers has been established, the platen motor is energized (step 528), and the carousel motor and the head motor drive all platen carousel and head motors in a predetermined manner. Energized to rotate (step 529) and polishing of the wafer is initiated (step 530). After the wafer has been polished, the head and carousel (attached to the bridge assembly) are raised away from the polishing head (step 531) and the head subcarrier is positioned from the lowest position inside the head so that the wafer can be easily separated from the pad. (Step 532). Polishing is completed when the wafer unloading process is complete (step 530).

The wafer unloading process (step 541) will now be described with respect to the schematic flowchart of FIG. Wafer unloading is initiated by extending the head subcarrier towards the head unloading module HULM (step 543) (step 542). Next, the HULM is moved to the "head" position (step 544). Next, the head flush operation is initiated to clean the space between the subcarrier and the retaining ring (step 545) and to clean the space between the retaining ring portion and the lower housing (step 546). Head flush switch “on” operation allows deionized (DI) water to be sent under pressure from an external source to the rotating assembly 116 (including the spindle 119) and via the mounting adapter 121 into the head and It communicates with the carrier-ring flush orifice and the ring-housing flush orifice via a fixture. The purge operation (step 545) also allows the removal of deionized water through the central bore 184 at the top surface of the subcarrier and through the radially extending bore or channel 191 and the central bore to the subcarrier-wafer mounting surface ( 147) to the rear side of the wafer. When an actuation insert is provided between the subcarrier-wafer mounting surface and the back side of the wafer, holes are also provided through the insert such that deionized water, compressed air or vacuum can be used through the insert. The purge operation also includes the use of high pressure clean dry air (CDA) through the subcarrier holes to push the wafer onto the HULM that is in close proximity to receive the wafer when the subcarrier is pushed out (step 546). If the wafer is pressed onto the HULMH on the subcarrier after the first purge operation, the HULM returns to its original position. Unfortunately, a single purge cycle may not always be enough to push the wafer out of the subcarrier and then the HULM is moved downwards. The process is repeated beginning with step 545 with additional purge cycles until the wafer is removed from the subcarrier and captured by the HULM.

Another embodiment-chamber subcarrier

Some embodiments of the structure and method of a chemical mechanical polishing head assembly having a floating wafer carrier (or subcarrier) and a retaining ring have been described so far and we will now describe some additional alternative embodiments. Another particularly specific embodiment described immediately after is directed to a substrate subcarrier, such as a semiconductor wafer subcarrier, and for convenience we have the same features as some of the features of subcarrier 160 already described and some additional features. It will be referred to as a recessed subcarrier 160 '. These additional features are described in detail below, as well as changes to the chemical mechanical polishing head assembly required to meet additional inventive subcarriers.

In order for the additional features provided by the recessed subcarrier 160 'to be understood more quickly, we first describe some of the features of the subcarrier 160 with reference to FIG. In one embodiment, subcarrier 160 is a rigid, round, nonporous ceramic disk having a diameter suitable for mounting or transporting a semiconductor wafer of approximately 200 mm or 300 mm. To date, subcarrier 160 has been described in connection with two pressure chamber embodiments of a polishing head. The first pressure chamber presses against the retaining ring assembly and the second pressure chamber presses against the subcarrier and indirectly against the wafer. Subcarrier 160 has a rectangular edge between upper surface 163 and lower surface 164 proximate cylindrical surface 85. The bottom surface 164 is conveniently stacked for flatness and smoothness. In FIG. 24, the lower surface 164 is protruded in the figure so that the features of the surface described below in relation to the recessed subcarrier 160 'are more quickly seen.

A fluid communication channel is provided at the subcarrier 160 that connects the aperture on the bottom surface 164 of the subcarrier or the opening of the orifice 147. These holes are in communication with the vacuum to assist in lifting and holding the wafer 113 from the back side of the wafer to the subcarrier (possibly via an optional polymer or other flexible film insert). The holes may also be used to pass compressed air or fluid to assist in ejecting the wafer from the subcarrier. These holes are in fluid communication with a single bore 184 through six radially extending bores 191 at the center of the subcarrier 160 to complete the connection with the center bore hole 184. Thereafter, the radially extending bore portion between the six vertically extending holes 147 and the cylindrical edge 185 of the subcarrier 160 may be a stainless steel plug 181 or other means of preventing the leakage of air, vacuum, pressure or water. Is filled. Of course, the number of holes 147 can be any number of holes so that vacuum pressure develops without twisting the subcarrier or wafer. The manner in which the vacuum pressure is communicated from the external source to the rotating head and the subcarrier via the rotating assembly has already been described.

We will now describe FIG. 25, which is a perspective view of the subcarrier 160 'generally seen at the lower surface 164, and FIG. 26, which is a partial cross-sectional view through the subcarrier, and the related alternative recessed subcarrier 160'. do. This embodiment of the present invention is for obtaining even and even uniformity of the wafer at or near the circumferential edge of the wafer. Even when the original flotation retaining ring combination and flotation carrier are used as described, there may be some minor surplus non-uniformity or flatness in polishing at or near the edge of the wafer. This surplus is generally 1 micron or less and may be more or less, but in many cases about 0.1 micron.

The subcarrier 160 ′ is an improved implementation of the subcarrier that can be used alone or in combination with the wafer carrier assembly 106 including the head mount assembly 104 and retaining ring assembly 167 described above. The major change on the subcarrier 160 'compared to the subcarrier 160 is that when used in conjunction with a groove, steel or non-porous material sheet 251 that forms a film that is generally elastic or flexible, the positive pressure is increased in the wafer ( A depression 250 is added to form a third pressure chamber that is applied to exert a force on the backside of 113 and thereby extends or attempts to extend as the polishing pressure increases on the wafer near the groove 250. We refer to this pressure as the edge transition chamber pressure (ETC). In some instances, it may be desirable to apply a negative pressure or vacuum to the groove and when the sheet of material 251 is at least somewhat compressible, the polishing pressure is reduced in the annular region adjacent to the groove. In some embodiments of the present invention, nonporous material sheet 251 may be an insert 161, for example, as is customarily used in the wafer polishing industry. A Rodel DF200 insert or reinforcement film or R200 reinforcement film can be used as the material sheet 251, for example. Rodel DF200 (Rodel Part No. A00736, type DF200) has a nominal thickness of 23 to 27 mils (0.58 to 0.69 mm millimeters), about 4.0 to 16.0 percent compressibility, and a moderately viscous 2 with synthetic rubber based on high shear adhesives. It is provided as a heavy coating polyester. The clean space version of this insert has a non-produced 0.002 inch silicone PET release liner that is removed during application.

By adjusting the amount of fluid injected into this chamber, or by changing the pressure in this third pressure chamber P3, the amount of material removed from the wafer can be optimized to achieve a more uniformly polished or planarized substrate (wafer) surface. Can be. Still other embodiments of grooved subcarriers are subcarriers having a plurality of grooves, such as concentric grooves having a shared pressure source, or a plurality of grooves, each having a separate pressure source. The latter plurality of groove embodiments (see Figure 27) allow for a suitable polishing force profile provided at different radial distances from the center to the edge of the wafer.

The manner in which the pressure developed in the groove 250 cooperates with the non-porous sheet material 251, 161 and the wafer 113 is schematically illustrated in FIG. 26. A fluid that maintains a constant pressure (positive or negative pressure), such as a gas or liquid that maintains a constant pressure, but usually clearly maintains a constant pressure, the wafer carrier assembly 106 through a possible entrance to the rotary assembly, tubing and fixtures. Is introduced into the central bore 184 '. Air maintained at a constant pressure from the central bore 184 'is one or more of which intersects a plurality of similar holes extending from the radially extending bore 191' to intersect the groove 250 on the lower surface of the subcarrier. Communication with the above radially extending bore 191 '. While a single channel can be used to communicate air at a constant pressure to the groove, the desirability of maintaining a uniform pressure throughout the groove and the structural advantages of keeping the dimensions of the voided area within the subcarrier small are numerous The channel implies that six channels are provided in this particular embodiment.

In this particular embodiment, the central bore 184 ', the radially extending bore 191' and the hole portion 147 'are different in pressure from the center bore in the embodiment described now compared to the wafer backside vacuum / pressure applying structure. Source, communicating with hole 147 'openings in channel 250 rather than directly on the lower subcarrier surface, and that backside vacuum / pressure is provided by separate vacuum pressure circuit openings on four new holes 260. Except for the points, they appear to be the same structure as described previously. This change has been provided since the location of the groove 250 in relation to the edge of the subcarrier and the pressure uniformity applied to the groove is more important than the location of the wafer backside vacuum / pressure hole 147 in the previously described embodiment. . In fact, retrofitting of the structure was only a matter of convenience, and those of ordinary skill in the art would appreciate the location of the grooves and the rear vacuum / pressure holes, while the way in which pressure and vacuum are provided to the structure is dependent upon the physical integrity of the subcarrier and As long as stability is maintained, you will see that it is not as important.

Further with reference to FIG. 26, a thin, substantially non-porous sheet material 251, here insert 161, blocks the groove to form a third chamber (P3) 262 so that pressure can develop in the chamber. Act to Normally, pressure is applied to the chamber only when the wafer 113 is mounted on the subcarrier and the wafer contacts the polishing pad, so that the pressure developed within chamber P3 262 is not sufficient to separate the insert from the subcarrier. It is not necessary to mount the insert 161 on the lower subcarrier surface beyond the insert mounting method of. The increase in pressure in chamber P3 causes a slight expansion or expansion in the size of the chamber and the resilient insert expands to some extent to press the portion of the wafer 263 in contact with the area of the insert. When the groove is an annular groove, this compression occurs uniformly in the annular area of the entire wafer. In general, since the amount of change of material removed on the wafer surface is less than about 1 micron and usually about 1/10 micron or less, the amount of expansion of this insert and wafer in FIG. 26 so that the operating rules can be explained in the figure The refraction of is exaggerated. Therefore, the actual expansion may not be detectable, but a somewhat larger polishing force is achieved.

In the embodiment shown in FIG. 26, the groove 250 is shown as a square or rectangular groove. However, it can be seen that the size of the grooves is important, but not the shape of the grooves, especially at the surface of the subcarrier where the edges 264, 265 of the groove 250 contact the insert 161. For example, the groove shown has two substantially vertical surfaces 266 and 267 and a ceiling portion 268. However, grooves with non-vertical or non-flat surfaces and ceilings, such as V-shaped, C-shaped or other non-flat grooves, may be employed. The manner in which the grooves on the lower subcarrier surface 164 open can also be modified to minimize any effects that surface discontinuities can provide.

The four wafer backside vacuum / pressure holes 260 shown in FIG. 25 are not visible in FIG. 26 due to the location of the cross section in cross section, but these holes are part of the carousel including FIG. 28 and this alternative grooved subcarrier. A cross-sectional assembly diagram, head mounted assembly, rotary assembly, and wafer carrier assembly of an embodiment of FIG. 29 can be seen in FIG. In the embodiment of the grooveless subcarrier described previously, six vacuum holes 147 (0.040 inches in diameter) are provided within the subcarrier opening on the bottom surface 164 of the subcarrier on which the subcarrier mounts the wafer backside. You can think of what happened. In this grooved subcarrier, four sets of holes 260 are provided and function in a similar manner. Each hole 260 extends vertically from the lower subcarrier surface 164 to traverse a channel 270 extending radially inward from the edge of the subcarrier. One end of the channel 270 is blocked (271) to form an airtight seal of air and liquid, while the other end traverses a second vertical bore 272 extending to the upper subcarrier surface 163. Extends to commit. How the holes are formed has been described above and will not be repeated here. The structure may be provided to provide an offset between the positions of the holes on the lower and upper subcarrier surfaces or other structures to provide that the fixture 273 does not interfere with the flange ring 146. In principle, a vertical bore that runs straight through the subcarrier can be provided to communicate air, water or vacuum to the wafer at a constant atmospheric pressure. Fixture 273 is attached to subcarrier bore 272 and tubing 274 so that a vacuum or pressure can be communicated to hole 260. In one embodiment of the invention, tubing from each of the four holes is connected to a source of vacuum, compressed air or water through a common tube and rotational combination within the wafer carrier assembly 106. These holes and channels may be provided at the back of the wafer to provide air or water or a combination of the two to maintain a wafer at the subcarrier during wafer unloading operation to maintain the wafer at the subcarrier. It is used to supply a vacuum.

A sheet of material 251, such as the insert 161, is used to complete the formation of the third chamber P3 and the holes are formed of a sheet of material such that vacuum, air at which constant pressure is maintained, and / or water are in direct communication with the back wafer surface. Is provided within.

In some embodiments of the present invention, the groove 250 is sized to have a depth of between about one and a half inch to about a tenth inch and a width between about one tenth and a half inch. The width can be larger or smaller and the depth can be thinner or deeper. Embodiments of the present invention having a depth of between about 0.04 inches (about 1 mm) and about 0.08 inches (about 2 mm) and grooves that are 0.12 inches or 0.14 inches or 0.16 inches wide have been improved compared to grooveless or flat subcarriers. Polishing results have also been achieved. In another particular embodiment, the groove is about 0.12 inches (about 3 mm) wide. In another particular embodiment, a combination of 0.08 inch deep and 0.16 inch wide grooves at the center of the radial distance of 3.64 inches from the center of the 200 mm diameter wafer subcarrier provides good results. In the case of a 300 mm diameter wafer subcarrier, the grooves are located in an appropriate position from the center so that edge grinding is similarly controlled.

The inventive groove structure 250 is generally between about 0.02 inches (about 0.5 mm) to about 0.2 inches (about 5 mm) deep or more, and more generally, between about 0.02 inches and about 0.1 inches, preferably The following is a depth of between about 0.08 inches in about 0.05 first person. When the resilient insert 161 is located on the subcarrier lower surface 164 and the wafer 113 is mounted therein, the penetration of the insert 161 into the groove 250, which may occur during polishing, may result in the depth of the groove. To be even smaller, the grooves must be deep enough so that such intrusion does not substantially interfere with the uniform application of pressure to the grooves and pressure chamber P3. On the other hand, the groove 250 should not be deep so that the structural strength or flatness of the subcarrier is compromised. Within this functional pressure, the groove can be at any depth. Details of the groove 250 and wafer backside holes 260 are shown in FIGS. 30 and 31. Apart from the addition of grooves 250, holes 260 and channels connecting this structure to the rotating assembly, the structures shown in Figures 28-31 are substantially the same as those described above with respect to Figures 4 and 5 and 7 and 8. The same, not repeated here. One additional port in the rotary joint is needed to provide pressure for the third chamber P3. In polishing profiles for oxide wafers using a grooved subcarrier with a grooved subcarrier with a width of 0.12 inches wide and a grooved depth of 0.08 inches and a depth of 10 psi with a 0 pis pressure equal to a grooveless subcarrier Experimental data showing the difference is shown in FIG. Some typical achievements are given in Table I and the parameters of the process to which these results apply are shown in Table II. In these tables, SS12 is the name for the polishing slurry distributed in the United States by Rodell and Klebosol 130N50 PHN is another polishing slurry by Cabot. The 49 mm 5mm-EE is a standard inspection process where 49 measurements are made on the wafer surface with 5mm edge exclusion (EE), while the 49mm 3mm-EE is 49 measurements with 3mm edge exclusion (EE) Another standard inspection procedure made on the surface of the wafer. This process is known in the art and will not be described herein any further.

Table I.

Table II.

In Figure 32, the percentage non-uniformity (NU%) is 7.69% for normal ambient pressure (0 psi), whereas the percentage non-uniformity is 3.23% and zero pressure (subcarrier without grooves) when the groove pressure is increased to 10 psi. Less than half from the non-uniform percentage of achievement). For example, the average removal rate for a wafer at both 0 psi and 10 psi from the graph of Figure 32 is about 2300 angstroms per minute while the minimum removal rate of about 1920 angstroms per minute at a distance of about 6 mm from the wafer edge for 0 psi is About 5mm from the edge is about 2110 angstroms per minute. This is merely an example of the beneficial results achieved in one embodiment of the invention rather than a limitation of the results that can be achieved.

The features of grooved subcarriers have been described so far as compared to grooveless or flat subcarriers, and we now turn our attention to grooved subcarriers with multiple grooves. A plurality of grooved subcarriers are especially used to reduce or eliminate both edge nonuniformity and the so-called donut-shaped or annular polishing effect. The annular polishing effect is: (i) the first situation in which the wafer is overpolished at the center and the corner and less polished between the center and the corner, or (ii) the second condition in which the wafer is less polished at the center and the edge and overground between the center and the corner. Include the situation. Multiple grooved embodiments also provide significant uniformity effects for 300 mm or larger wafer polishing machines.

In one embodiment, as shown in FIG. 27, three grooved subcarriers 280 are provided. Three grooves provide an additional level of grinding control. Subcarriers with two, four, five or more grooves are also provided, particularly as the size of the wafer being polished increases. Each groove 281, 282, 283 has already been described which communicates with a separate source of air at which constant pressure is maintained and requires additional types of rotary binder ports. The provision of this additional rotating assembly and / or rotating port is no longer described. Each of the three grooves 281, 282, 283 is formed and operates in the manner already described and such description is not repeated here. When space in a subcarrier for a channel becomes an issue, some channels may be formed at different depths within the subcarrier, and the number of channels per groove may be somewhat reduced, for example from two to four channels from six channels. And other channels may be provided using fixtures and tubing rather than bores in the subcarrier.

In a plurality of grooved chamber embodiments, each of the plurality of grooves may be positioned at will to effectively achieve the desired polishing pressure profile, and it is convenient to discuss the polishing zone in the context of at least one embodiment of the present invention. . In the embodiment of the three grooved subcarrier 280, the first groove 281 is located at a distance between about 0.10 inch and about 1.2 inches from the edge of the subcarrier to overcome over or less polishing of any edge. Preferably located in the first annular zone. The second groove 282 is about 1.2 inches (inside the first zone) to aid in modifying the annular polishing process, which is over-polishing (under-polishing) at the center and corners and under-polishing (over-polishing) between the center and the corners. Radius) located in a second zone located between about 2.7 inches. Finally, the third groove 283 is located between about 2.7 inches of the edge of the wafer (inner radius range of the second zone) and the center of the subcarrier to overcome the over-polishing (under-polishing) of the wafer in the central region. It is located in the third zone. Annular grooves are more desirable due to their symmetry and are likely to provide more uniform polishing pressures, while similar polishing profiles are alternatively achieved as a plurality of separate radial arcs, circular patches or other distributions of pressure on the surface of the subcarrier. Can be. Furthermore, the annular groove can be combined with other non annular pressure patches. Within each of these zones, the home itself can be located anywhere within the zone and is sized as previously described.

In a further embodiment of the present invention, the amount of material removed or remaining can be monitored during the polishing process and the pressure on one or more chambers can be modified accordingly to achieve uniform polishing. Such end point detection may use electronic, magnetic or optical detection methods and would be connected to a computer control system for regulating pressure on the subcarrier, retaining ring and / or one or more grooves provided.

Normally, although these ranges are contiguous, at least about a tenth of an inch of separation must be provided between the other grooves. The pressure in each of the grooves is generally positive pressure (typically 0 to 15 psi) or vacuum. Often, the exact position of the grooves and the pressure or vacuum applied to the grooves are adjusted based on the nature of the process so that the exact position and pressure are usually not suitable for the respective application.

Subcarriers having a single groove and having a plurality of grooves of the present invention can be used in combination with the floating head and the floating retaining ring, but those that do not use the wafer subcarrier assembly 106 or the head mounting assembly described above in detail. It can also be adapted to other substrate polishing and planarization machines and applications. The grooved subcarrier of the present invention will be applied to any polishing head application which is desirable to quickly change the polishing profile of the wafer as a function of radial position.

The foregoing invention has been described in some detail by way of illustration and example for clarity of understanding, but any change and modification may be made by those skilled in the art without departing from the spirit or scope of the appended claims. You can easily see. All publications and patent applications cited herein are hereby incorporated by reference as if each individual publication or patent application were specifically and individually described by reference.

Claims (38)

Housings, A disk carrier for mounting a substrate to be polished, A retaining ring surrounding the carrier to retain the substrate in a pocket defined by the retaining ring and one surface of the carrier; A first flexible coupling attaching the retaining ring to the carrier such that the retaining ring can translate in at least one dimension and be tilted about an axis relative to the carrier; A second flexible coupling attaching the carrier to the housing such that the carrier can translate in at least one dimension and be tilted about an axis relative to the housing; The housing and the first flexible coupling may comprise a first chamber in fluid communication with a first source of compressed gas such that a first force is applied to the retaining ring when gas at a first pressure is in communication with the first chamber. Forming, The housing and the second flexible coupling may comprise a second chamber in fluid communication with a second source of compressed gas such that a gas at a second pressure exerts a second force on the subcarrier when in communication with the second chamber. Polishing apparatus, characterized in that the forming. The polishing apparatus according to claim 1, wherein the translational motion and the inclination of the carrier are independent of the translational motion and the inclination of the retaining ring. A polishing apparatus according to claim 1, wherein the translational movement and the inclination of the carrier are connected to the translational movement and the inclination of the retaining ring to a predetermined degree. The polishing apparatus according to claim 1, wherein the translational movement and the inclination of the carrier and the translational movement and the inclination of the retaining ring each have an element that is independent of the other and an element that depends on the other. 5. A polishing apparatus according to claim 4, wherein the degree of translation of the translational motion and the inclination of the carrier and the ring depends on the material properties of the first and second flexible couplings and the geometrical properties of the attachment portion. 6. The method of claim 5, wherein the material properties affecting the degree of coupling include elasticity, toughness and spring constant, and the geometrical properties are the distance between the attachment locations between the ring and the carrier and the distance between the attachment locations between the carrier and the housing. And a geometry of the interface between the first and second diaphragms and adjacent structures of the housing, the retaining ring and the carrier. The polishing apparatus according to claim 1, wherein the first pressure and the second pressure are different pressures. The polishing apparatus of claim 1, wherein the first pressure and the second pressure are substantially the same pressure. The polishing according to claim 1, wherein the first pressure and the second pressure are actually the same pressure and the force exerted on the retaining ring and the carrier is determined by the surface area of the retaining ring and the carrier on which each pressure is applied. Device. The polishing apparatus according to claim 1, wherein the first pressure and the second pressure can be independently a positive pressure or a negative pressure (vacuum). The polishing apparatus according to claim 10, wherein the depth of the pocket formed by the surface of the carrier and the inner cylindrical surface of the retaining ring is determined by the first pressure and the second pressure during the substrate loading step. A polishing apparatus according to claim 1, wherein the substrate comprises a semiconductor wafer. 2. The retaining ring of claim 1, wherein the retaining ring has a lower surface in contact with the outer polishing pad during polishing, an inner cylindrical surface disposed adjacent to the periphery of the outer peripheral surface of the carrier and the substrate mounting surface of the carrier, and the retaining ring contacts the pad during polishing. And a pad adjusting member disposed in the lower outer radial portion of the retaining ring, the pad adjusting member defining a shape profile varying between a first plane parallel to the plane of the polishing pad and a second plane perpendicular to the polishing pad; A surface and the peripheral surface of the carrier mounting surface form a pocket for holding the substrate during polishing. The polishing apparatus of claim 13, wherein the pad adjusting member provides an angle between 15 ° and 25 ° that is not parallel to the nominal plane of the polishing pad. 15. The polishing apparatus of claim 13, wherein the pad adjustment member provides an angle between 18 degrees and 22 degrees that is not parallel to the nominal plane of the polishing pad. 14. The polishing apparatus of claim 13, wherein the pad adjustment member provides an angle of 20 degrees that is not parallel to the nominal plane of the polishing pad. 15. The apparatus of claim 13, wherein the pad adjustment member provides an angle of 20 degrees that is not parallel to the nominal plane of the polishing pad, and further comprises a second angle of 70 degrees that is not parallel to the nominal plane of the polishing pad. Polishing apparatus, characterized in that provided. The portion of claim 13, wherein the portion providing an angle of 20 ° extends by a distance between 0.03 and 0.04 inches from the lower planar retaining ring surface, and the portion providing an angle of 70 ° is at least about 0.2 from the lower planar retaining ring surface. Polishing apparatus, characterized by extending to inches. 15. The pad adjustment member of claim 13, wherein the pad adjustment member comprises an angle between 15 ° and 25 ° that is not parallel to the nominal plane of the polishing pad and a second angle between 65 ° and 75 ° that is not parallel to the nominal plane of the polishing pad. Polishing apparatus, characterized in that provided. The polishing apparatus of claim 1, wherein the first pressure on the carrier is in the range between 1.5 and 10 psi and the second pressure on the retaining ring is in the range between 1.5 and 9.0 psi. The polishing apparatus of claim 1, wherein the flexible coupling comprises a diaphragm. The polishing apparatus of claim 1, wherein the diaphragm is formed from a material selected from the group consisting of metals, plastics, rubbers, polymers, titanium, stainless steel, carbon fiber composites and combinations thereof. The polishing apparatus of claim 1, wherein the carrier is formed from a ceramic material. A lower surface in contact with the external polishing pad during polishing, An inner cylindrical surface disposed adjacent to the outer peripheral surface of the carrier and the peripheral surface of the substrate mounting surface of the carrier, A pad adjusting member disposed in the lower outer radial portion of the retaining ring in contact with the pad during polishing and forming a varying profile between a first plane parallel to the plane of the polishing pad and a second plane perpendicular to the polishing pad Including, And the inner cylindrical surface and the carrier mounting surface circumference form pockets for holding the substrate during polishing. The substrate retaining ring of claim 24, wherein the pad adjustment member provides an angle between 15 ° and 25 ° that is not parallel to the nominal plane of the polishing pad. 25. The polishing apparatus of claim 24, wherein the pad adjusting member provides an angle between 18 degrees and 22 degrees that is not parallel to the nominal plane of the polishing pad. 25. The substrate retaining ring of claim 24, wherein the pad adjustment member provides an angle of 20 degrees that is not parallel to the nominal plane of the polishing pad. 25. The apparatus of claim 24, wherein the pad adjustment member provides an angle of 20 [deg.] That is not parallel to the nominal plane of the polishing pad, and further comprises a second angle of 70 [deg.] That is not parallel to the nominal plane of the polishing pad. And a substrate retaining ring. The portion of claim 24, wherein the portion providing an angle of 20 ° extends by a distance between 0.03 and 0.04 inches from the lower planar retaining ring surface, and the portion providing an angle of 70 ° is at least about 0.2 from the lower planar ring ring surface. A substrate retaining ring extending to inches. The pad adjustment member of claim 24, wherein the pad adjustment member is at an angle between 15 ° and 25 ° that is not parallel to the nominal plane of the polishing pad and a second angle between 65 ° and 75 ° that is not parallel to the nominal plane of the polishing pad. And a substrate retaining ring. Supporting the back side of the wafer with a wafer support subcarrier; Applying abrasive force to the support subcarrier to compress the front face of the wafer against a polishing pad; Suppressing movement of the wafer from the support subcarrier during polishing with a retaining ring disposed circumferentially around a portion of the subcarrier and around the wafer. 32. The method of claim 31 wherein the pad adjustment force is applied independently of the polishing force. 32. The method of claim 31, wherein the pad adjustment force is coupled to the polishing force. 32. The pad adjustment force according to claim 31, wherein the pad adjustment force is determined by the first zone of the pad perpendicular to the plane defined by the pad surface, the pad in the direction having the first element perpendicular to the plane and the second element parallel to the plane. Applied to the second zone. An article of manufacture comprising a semiconductor wafer polished according to the method of claim 31. An article of manufacture comprising a semiconductor wafer planarized according to the method of claim 34. The wafer-mounted surface of claim 1, wherein the disk-shaped carrier further comprises at least one cavity formed in the wafer mounting surface of the carrier and a fluid communication channel extending from the at least one cavity to an external source of compressed fluid. A flexible membrane, said membrane covering said at least one cavity to form a third chamber capable of maintaining pressure when said compressed fluid is communicated from said external source of compressed fluid to said at least one cavity, said membrane being And when the compressed fluid is in communication with the third chamber, expands and exerts a force on the wafer mounted between the film and the external polishing pad during polishing. A semiconductor wafer carrier for holding a semiconductor wafer during a planarization operation, The wafer carrier, A disc-shaped block made of a non-porous material having a first surface for mounting a semiconductor wafer, a second surface, and a third cylindrical surface connecting the first and second surfaces; A fluid communication channel extending from the cavity to the second or third surface to communicate compressed fluid to the cavity from an external source of compressed fluid, The first face is a real plane except for a non-planar cavity extending from the plane into the interior of the wafer carrier, The first surface is adapted to receive a flexible membrane covering the cavity and form a chamber capable of maintaining pressure when the compressed fluid is communicated from the external source of compressed fluid to the cavity, And the film expands and exerts a force on the wafer mounted on the film when the compressed fluid is in communication with the third chamber.