KR20050044404A - Electropolishing assembly and methods for electropolishing conductive layers - Google Patents

Abstract

In one aspect of the invention, an exemplary apparatus and method for electropolishing a conductor film on a wafer 1004 is disclosed. The apparatus includes a wafer chuck 1002 for holding a wafer, an actuator 1000 for rotating the wafer chuck, and a nozzle 1010 configured to electropolize the wafer. The device may also include a conductor ring or shroud 1006. The method of electropolishing the conductor film on the wafer includes rotating the wafer chuck at a rate sufficient to allow electrolyte fluid incident on the wafer to flow to the surface of the wafer towards the edge of the wafer.

Description

ELECTROPOLISHING ASSEMBLY AND METHODS FOR ELECTROPOLISHING CONDUCTIVE LAYERS}

Related Applications

This application is herein incorporated by reference, and methods of electropolishing metal films on substrates filed on November 13, 2001, filed in US Patent Provisional Application No. 60 / 332,417 and filed on April 4, 2002; and US Patent Provisional Application No. 60 / 372,567, entitled Apparatus, claims priority.

BACKGROUND OF THE INVENTION Field of the Invention The present invention generally relates to semiconductor processing devices, and more particularly to electrolytic polishing devices for electropolishing conductor layers on semiconductor devices.

Semiconductor devices are fabricated on semiconductor wafers using a number of different processing steps to form transistors and interconnect devices. In order to electrically connect transistor terminals associated with the semiconductor wafer, conductor (eg, metal) trenches, vias, etc. are formed in the dielectric material as part of the semiconductor device. Trenches and vias connect electrical signals and power between transistors, internal circuitry of semiconductor devices, and external circuitry of semiconductor devices.

When forming the interconnect device, the semiconductor wafer is subjected to, for example, a masking, etching, and deposition process to form the desired electronic circuit of the semiconductor device. In particular, multiple masking and etching steps may be performed to form a pattern of recessed regions in the dielectric layer on the semiconductor wafer, which acts as trenches and vias for interconnects. A deposition process is then performed to deposit the metal layer on the semiconductor wafer to deposit metal in the trenches and vias and on the unrecessed areas of the semiconductor wafer. To isolate the interconnects, such as patterned trenches and vias, metal deposited on unrecessed regions of the semiconductor wafer is removed.

Conventional methods for removing metal films deposited in unrecessed regions of dielectric layers on semiconductor wafers include, for example, chemical mechanical polishing (CMP). CMP methods are widely used in the semiconductor industry to polish and planarize metal layers in trenches and vias along with unrecessed regions of dielectric layers to form interconnect lines.

In a CMP process, the wafer assembly is placed over a CMP pad located on a platen or web. The wafer assembly includes a substrate having one or more microstructures and / or layers, such as interconnect elements formed in the dielectric layer. Force is applied to press the wafer assembly against the CMP pad. The CMP pad and substrate assembly are moved together while applying force to polish and planarize the surface of the wafer. A polishing solution, often referred to as a polishing slurry, is dispensed on the CMP pad to facilitate polishing. Polishing slurries generally contain an abrasive and are chemically reactive to selectively remove unwanted materials, such as metal layers, from the wafer more quickly than other materials, such as dielectric materials.

However, the CMP method is associated with a fairly strong mechanical force and can seriously affect the underlying semiconductor structure. For example, when the interconnect structure is reduced to 0.13 μm or less, there may be a large difference between the mechanical properties of the conductor material, for example copper and the low k film used in common damascene processes. For example, the Young Modulus of a low k dielectric film may be at least ten times smaller than the Young's modulus of copper. As a result, the significant mechanical forces exerted on the dielectric film and copper in the CMP process among other processes cause stress-related defects in the semiconductor structure, including delamination, dishing, corrosion, film lifting, scratching, and the like. You can.

Therefore new processing techniques are required. For example, the metal layer may be removed or etched from the wafer using an electropolishing process. In general, a portion of the wafer to be polished in the electrolytic polishing process is immersed in an electrolyte fluid solution and then charge is applied to the wafer. These conditions cause copper to be removed or polished from the wafer.

1A and 1B are cross-sectional and plan views, respectively, of an exemplary semiconductor processing apparatus including a protective shroud;

1C, 1D and 1E are cross-sectional views of exemplary nozzles of a semiconductor processing apparatus,

2 is a cross-sectional view of an exemplary nozzle of a semiconductor process apparatus,

3 is a cross-sectional view of an exemplary nozzle of a semiconductor process apparatus,

4 is a cross-sectional view of an exemplary nozzle and block of a semiconductor process apparatus,

5A-5H are cross-sectional views of the shape and structure of various exemplary nozzles,

6A and 6B are cross sectional and top views of an exemplary nozzle structure,

6C and 6I are plan views of various exemplary nozzle structures,

7 is a cross sectional view of an exemplary semiconductor processing apparatus including a conductor member,

8A and 8B are cross-sectional views of an exemplary semiconductor processing apparatus including a conductor member,

8C is an enlarged view of an example wafer chuck assembly including a conductor member,

9A and 9B are cross sectional views of an exemplary semiconductor processing apparatus including a conductor member,

10A and 10B are cross sectional views of an exemplary semiconductor processing apparatus including one and two optical sensors, respectively;

11A and 11B are plan and cross-sectional views of an exemplary semiconductor processing apparatus,

12 is a cross sectional view of an exemplary semiconductor processing apparatus,

13A and 13E show an exemplary electropolishing assembly with multiple rotary assemblies,

14A and 14B are cross sectional views of an exemplary multi-spinning nozzle assembly,

14C shows an exemplary process of electropolishing a conductor layer on a wafer,

15 is a cross sectional view of an electropolishing chamber with an exemplary multiple linear movable nozzle assembly, and

16A-16E are exemplary views of an electropolishing apparatus having a linearly movable multi-rotating nozzle.

In one aspect of the invention, an exemplary apparatus and method for electropolishing conductor films on a wafer are provided. One exemplary apparatus includes a wafer chuck to hold a wafer, an actuator to rotate the wafer chuck, a nozzle configured to electropolise the wafer, and a shroud located around an edge of the wafer. One exemplary method of electropolishing conductor films on a wafer includes rotating the wafer chuck at a speed sufficient to allow electrolyte fluid incident on the wafer to flow toward the edge of the wafer on the surface of the wafer.

The present invention will be more readily understood by considering the following description in conjunction with the accompanying drawings and claims.

For a more complete understanding of the invention, the following description sets numerous specific details such as specific materials, parameters, and the like. However, it is to be understood that the above description is not intended to limit the scope of the present invention but instead is provided to better describe exemplary embodiments of the present invention.

I. Exemplary Electropolishing Apparatus

1A and 1B are cross-sectional and top views of an exemplary wafer electropolishing apparatus that may be used to polish the wafer 1004. In general, an exemplary electrolytic polishing apparatus works by directing the flow of electrolyte fluid towards a metal film on the wafer while charge is applied to the wafer. The charge and electrolyte fluid dissolve the metal ions in the metal film into the electrolyte fluid. The current density of the electrolyte fluid and the concentration of metal ions in the electrolyte fluid at least partially determine the polishing rate. Therefore, by controlling the current density, the electrolyte solution concentration, and the like, the electrolytic polishing apparatus may accurately polish the metal layer disposed on the semiconductor wafer.

As shown in FIG. 1A, the electropolishing apparatus may include a chuck 1002, an actuator 1000, and a polishing receptacle 1008. Polishing receptacle 1008 is acid and corrosion resistant and electrically insulated such as polytetrafluoroethylene (commercially known as TEFLON), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polypropylene, and the like. It can be made from any material. Preferably, the polishing receptacle 1008 may be formed from PVDF. However, it should be understood that the polishing receptacle 1008 may be formed of different materials, depending on the application.

As shown in FIG. 1A, electrolyte fluid 1038 may flow into polishing receptacle 1008 through nozzles 1010, 1012, and / or 1014. More specifically, the pump 1020 pumps the electrolyte fluid 1038 from the electrolyte fluid reservoir 1070 to the pass filter 1018 via the return valve 1024. The pass filter may include a liquid flow controller (LMFC) capable of controlling the amount and velocity of electrolyte fluid 1038 delivered to the nozzles 1010, 1012, and 1014. Additionally, pass filter 1018 may enter the polishing receptacle 1008 through nozzles 1010, 1012, or 1014 and may deteriorate the electrolytic polishing process or block the LMFC if LMFCs are used. Contaminants may be filtered out of the electrolyte fluid 1038 to reduce. In this way, contaminants are prevented from entering the polishing receptacle 1008 or blocking the LMFC. In this example, the pass filter 1018 suitably removes particles of about 0.05 to about 0.1 μm or more. However, it should be understood that various filtering systems may be used depending on the particular application. Additionally, although it is advantageous to filter contaminants, the pass filter 1018 may be omitted from the wafer polishing assembly in certain applications.

Electrolyte fluid 1038 may comprise a conventional electrolytic polishing fluid, such as phosphoric acid. Preferably, the electrolyte fluid 1038 comprises orthophosphoric acid (H ₃ PO ₄ ) having a concentration ranging from about 60% to about 85% by weight, preferably about 76% by weight. Additionally, electrolyte fluid 1038 preferably comprises glycol in the range of about 10 to 40 weight percent, the remainder comprises H ₃ PO ₄ having water and about 1% aluminum metal (by weight of acid). . However, the concentration and composition of the electrolyte fluid 1038 may vary depending on the particular application.

The pump 1020 may include certain hydraulic pumps, such as centrifugal pumps, diaphragm pumps, bellows pumps, and the like. In addition, the pump 1020 may be resistant to acid, corrosion, and contamination. While one pump 1020 is shown, it should be appreciated that any number of pumps 1020 may be used. For example, separate pumps may be used for each of the nozzles 1010, 1012, and 1014. Additionally, electrolyte fluid 1038 may flow into polishing receptacle 1008 through nozzles 1010, 1012, and 1014 without pump 1020 in certain applications. For example, electrolyte fluid 1038 may be maintained at a pressure in electrolyte fluid reservoir 1070. Additionally, the supply line between electrolyte fluid reservoir 1070 and nozzles 1010, 1012, and 1014 may be maintained at a predetermined pressure.

The LMFC may more preferably include a conventional flow controller that resists acid, corrosion, and contamination. In addition, the LMFC delivers the electrolyte fluid 1038 to the nozzles 1010, 1012, and 1014 at a set flow rate. Additionally, the LMFC may suitably deliver the electrolyte fluid 1038 at a flow rate proportional to the cross sectional areas of the nozzles 1010, 1012, and 1014. For example, if the diameter of the nozzle 1012 is larger than the nozzle 1014, it may be desirable for the LMFC to deliver the electrolyte fluid 1038 at a higher flow rate at the nozzle 1012. In this embodiment, the LMFC is preferably configured to deliver the electrolyte fluid 1038 at a flow rate ranging from 0.5 liters per minute to 40 liters per minute, depending on nozzle size, distance between the nozzles and the wafer, and the like.

The fluid reservoir 1070 may further include a heat exchanger 1036, a cooler / heater 1034, and a temperature sensor 1032 for controlling the temperature of the electrolyte fluid 1038 in the fluid reservoir 1070. In addition, one or more electrodes 1028 may be included in the reservoir 1070 and connected to the power supply 1030. When charge is applied to the electrode 1028, metal ions may be removed from the electrolyte fluid 1038 to adjust the metal ion concentration of the electrolyte fluid 1038. The opposite charge may be applied to electrode 1028 to add metal ions to electrolyte fluid 1038.

The example wafer polisher assembly further includes an electrode disposed within the nozzles 1012 and 1014. As will be described in more detail below, the present embodiment includes two nozzles having two electrodes therein, but a predetermined number of nozzles and two or more electrodes per nozzle may be used. In general, increasing the surface area of the electrode in the nozzle increases the current density and electrolytic polishing rate over the flow profile of the electrolyte fluid 1038.

As shown in FIGS. 1D and 1E, the nozzles 1012 and 1014 include electrodes 1056 and 1060, respectively. Electrodes 1056 and 1060 may include certain electrically conductive materials, such as copper, stainless steel, tantalum (Ta), titanium (Ti), TaN, TiN, lead, platinum, and the like.

During the electropolishing process, some of the metal ions moving out of the metal layer on the wafer 1004 may accumulate on the electrodes 1056 and 1060. As discussed below, metal buildup or plating may be removed in a deplating process. For example, when electrodes 1056 and 1060 are positively charged and wafer 1002 is negatively charged, wafer 1004 is electroplated rather than electropolished. In this and similar manners, the metal plated on the electrodes 1056 and 1060 may be removed, ie deplated. Alternatively, electrodes 1056 and 1060 may be appropriately replaced at appropriate times. For example, electrodes 1056 and 1060 may be replaced after processing about 100 wafers.

In certain examples, the metal layer may comprise copper. Thus, during the electrolytic polishing process, some of the copper ions from the metal layer to be polished move to electroplate the electrodes 1056 and 1060. However, if electrodes 1056 and 1060 include copper, electrodes 1056 and 1060 dissolve and deform during the deplating process. Therefore, in certain examples, electrodes 1056 and 1060 preferably include a material that resists dissolution during the deplating process. For example, electrodes 1056 and 1060 may comprise platinum or a platinum alloy. Alternatively, electrodes 1056 and 1060 may comprise titanium, suitably coated with a platinum layer having a thickness, for example, in the range from about 50 microns to about 400 microns.

In the present example device, wafer chuck 1002 properly holds and positions wafer 1004 in or on receptacle 1008. More specifically, the wafer 1004 is suitably positioned within the shroud 1006 and opposite the nozzles 1010, 1012, and 1014. Protective cover 1006 may optionally be included around wafer 1004 to prevent splashing as will be described in detail below.

After the wafer 1004 is properly positioned within the polishing receptacle 1008, the electrodes 1056 and 1060 are electrically charged by the power supply 1040. Additionally, wafer 1004 is electrically charged by power supply 1040. Alternatively, one or more power sources may be used to charge the electrodes 1056 and 1060 and the wafer 1004. When the electrodes 1056 and 1060 and the wafer 1004 are properly charged and the electrolyte fluid 1038 flows between the electrodes 1056 and 1060 and the surface of the wafer 1004 in the nozzles 1012 and 1014, an electrical circuit is formed. do. More specifically, electrodes 1056 and 1060 are electrically charged to have a negative potential compared to wafer 1004. In response to these negative potentials of electrodes 1056 and 1060, metal ions migrate from wafer 1004 to electrolyte fluid 1038, electrolytically polishing wafer 1004. However, when the polarity of the circuit is changed, metal ions move toward the wafer 1004 to electroplate the wafer 1004.

Additionally, as shown in FIGS. 1A and 1C, nozzle 1010 includes injection nozzle 1052 and termination detector 1016. During the electropolishing process, the spray nozzle 1052 is configured to supply electrolyte fluid 1038 and the termination detector 1016 may be configured to detect the thickness of the metal layer on the wafer 1004. Termination detector 1016 may include various sensors, such as ultrasonic sensors, optical reflecting sensors, electromagnetic sensors such as Eddy-current sensors, and the like. Electrolyte fluid 1038 supplied by injection nozzle 1052 acts as a medium through which termination detector 1016 emits a signal and measures metal film thickness. Using the electrolyte 1038 as a single medium to transmit a signal increases the measurement accuracy taken by the termination detector 1016 because the electrolyte fluid 1038 provides a single face. Conversely, if the spray nozzle 1052 does not provide electrolyte fluid 1038, the discharge and measurement from the termination detector will not pass through the electrolyte fluid 1038 applied to the wafer 1004 by the nozzle 1012 or 1014. It may also penetrate various other media such as air. As described below, the accuracy of the termination measurement increases due to the updated or real-time nature of the electrolyte fluid 1038, which may change over time. Also, although one nozzle 1010 with one termination detector 1016 is shown, any number of nozzles with any number of termination detectors may be used.

As shown in FIG. 1A, the actuator 1000 can rotate the chuck 1002 and the wafer 1004 around the z axis. Moreover, in certain applications, the actuator 1000 can move the chuck 1002 and the wafer 1004 along the x direction, and the nozzles 1010, 1012, and 1014 remain stationary. In certain applications, the nozzles 1010, 1012, and 1014 may move along the x direction, and the chuck 1002 and the wafer 1004 remain fixed along the x direction. In other applications, the actuator 1000 can move the chuck 1002 and the wafer 1004 in the x direction, and the nozzles 1010, 1012, and 1014 also move along the x direction.

Moreover, the electroplating apparatus may be directed in alternative forms. For example, nozzles 1010, 1012, and 1014 may be located on wafer 1004 such that electrolyte fluid is directed down toward wafer 1004. Additionally, wafer 1004 may be directed perpendicularly to nozzles 1010, 1012, and 1014 that direct electrolyte fluid towards wafer 1004.

For further details of an exemplary wafer electropolishing apparatus, see US Pat. No. 6,395,152, entitled Method and Apparatus, for electropolishing metal interconnects on semiconductor devices referenced herein and filed July 2, 1999. Moreover, for further details of exemplary termination detectors, see US Pat. No. 6,447,688, entitled Method and Apparatus for Termination Detection, referenced herein and filed May 12, 2000.

II. Electrolytic Fluid Splash Protection

Exemplary electropolishing methods include rotating the wafer 1004 while the electrolyte fluid 1038 is directed at the surface of the wafer 1004. Wafer 1004 is rotated at a speed sufficient to generate a centrifugal force that causes incident electrolyte fluid 1038 to flow across the surface of wafer 1004 toward the edge of wafer 1004. Preferably, electrolyte fluid 1038 flows to the edge of wafer 1004 before falling off the surface. By directing the flow across the surface of the wafer 1004, fluid may be prevented from falling off the wafer surface and disrupting the flow of the electrolyte fluid 1038 or forming a continuous column of electrolyte fluid in the receptacle 1008. However, the process may cause the electrolyte fluid to splash within the receptacle and leave the device or impede the flow of the electrolyte fluid. Thus, an exemplary electropolishing apparatus may employ a protective cover 1006 positioned around the wafer 1004 to reduce or prevent centrifugal liquid from splashing or retracting from the receptacle 1008. Include.

1A and 1B show a protective cover 1006 configured to enclose a wafer 1004 and a chuck 1002. As shown in FIG. 1A, the nozzle 1012 may supply a flow of electrolyte fluid to the surface of the wafer 1004. In order to more uniformly polish the metal film on the wafer 1004, the wafer 1004 is chucked 1002 across the wafer 1004 without allowing electrolyte to fall from the surface of the wafer 1004 into the polishing receptacle 1008. It can be rotated in a manner to flow the electrolyte 1038 to the exposed portion of the. Any electrolyte that forms a continuous column of electrolyte fluid between the wafer 1004 and the polishing receptacle 1008 away from the wafer 1004 causes over-polishing of the wafer 1004 to form a column. . Additional polishing may result in non-uniform and unpredictable polishing rates of the metal layer.

Additionally, certain electrolyte fluids falling from wafer 1004 or splashing into receptacle 1008 may interfere with the flow of electrolyte fluid supplied by nozzle 1012. The formation of the electrolyte fluid 1038 flow, or more specifically the profile, in turn affects the current density and the polishing rate of the electrolytic polishing apparatus. Therefore, it is desirable to flow electrolyte fluid 1038 along the surface of wafer 1004 toward the edge of wafer 1004 and away from the flow of electrolyte fluid 1038 directed at wafer 1004.

The wafer 1004 may be rotated at an appropriate rotational speed depending on the viscosity of the electrolyte fluid used so that the electrolyte flows across the wafer 1004 toward the edge of the wafer 1004 or toward the exposed portion of the chuck 1002. Can be. The rotational speed should be set such that the electrolyte fluid 1038 flows across the wafer 1004 without forming a continuous column away from the surface of the wafer 1004 or disrupting the flow of the electrolyte fluid 1038. In particular, the lower the viscosity of the electrolyte fluid, the higher the required centrifugal acceleration. For example, for 85% phosphoric acid, the centrifugal acceleration may be chosen to be at least about 1.5 m / s ² . In an exemplary method, a 300 mm diameter wafer is rotated in a range from about 100 rpm to about 2,000 rpm or more, preferably from about 1500 rpm to about 2,000 rpm.

Generally, the nozzles 1012 or 1014 will scan the entire surface of the wafer 1004 to polish the wafer 1004 more evenly. When the nozzle 1012 is scanning different portions of the wafer 1004, the wafer 1004 can be rotated to form a constant centrifugal acceleration with respect to the incident electrolyte fluid 1038. For example, centrifugal acceleration is proportional to the square of the rotational speed and the radius from the center of the wafer. Therefore, the speed at which the wafer 1004 is rotated is reduced when the nozzle 1012 or 1014 polishes a portion of the wafer 1004 near the edge of the wafer 1004, ie at a large radius, and the center of the wafer 1004. That is, when polishing a portion of the wafer at a small radius.

In general, when electrolyte fluid is supplied to wafer 1004 in the manner described above, electrolyte fluid flows toward the edge of wafer 1004 and passes over wafer 1004 towards the wall of polishing receptacle 1008. Without the shroud 1006, the electrolyte fluid 1038 contacts the wall of the polishing receptacle 1008 and splashes in the receptacle 1008 to hinder the flow of the electrolyte fluid 1038 or out of the polishing receptacle 1008.

As shown in FIGS. 1A and 1B, the protective cover 1006 may include a wafer 1004 and a wafer 1004 to reduce or prevent the electrolyte fluid 1038 from splashing within the polishing receptacle 1008 or escaping from the polishing receptacle 1008. It may be located around the chuck 1002. Moreover, the shroud 1006 can move in the x direction with the chuck 1002 and the actuator 1000 during the polishing process. In particular, the protective cover 1006 may be attached to the chuck 1002 and / or the actuator 1000 by mechanical attachments, joints, or the like. Alternatively, another actuator capable of synchronizing the movement of the shroud 1006 with the chuck 1002 and the actuator 1000 may separately drive the shroud 1006. Protective cover 1006 may also be coordinated with chuck 1002 or rotated separately from chuck 1002.

The protective cover 1006 may be formed in any suitable form such as a circle, a polygon, or the like. Protective cover 1006 is preferably formed to reduce the splash of electrolyte fluid 1038 and to contain electrolyte fluid 1038 in receptacle 1008 after electrolyte fluid flows from wafer 1004. The gap between the chuck 1002 and the shroud 1006 may be for example in the range of about 1 mm to about 10 mm, preferably about 5 mm. Additionally, as shown in FIG. 1A, the cross section of the sidewall of the shroud 1006 may be formed in an L shape to prevent electrolyte fluid from splashing over the shroud 1006 or the chuck 1002. However, the cross section of the protective cover 1006 may have various shapes. For example, the side wall of the protective cover 1006, ie, the vertical portion of the L shape, may be formed in other shapes such as C-shape or the like. In addition, the protective cover 1006 may be tapered in or out to reduce splashes and the like. Protective cover 1006 may extend above or below wafer 1004 and chuck 1002 than shown in FIG. 1A.

The protective cover 1006 may be made from a plastic, ceramic, or the like, or a corrosion resistant metal or alloy such as tantalum, titanium, or 300 series stainless steel. Additionally, protective cover 1006 may be coated with a material that resists electrolyte fluid, such as Teflon.

However, it should be appreciated that the electrolytic polishing method described above does not require electrolyte fluid 1038 to flow past the edge of the wafer and enter the protective lid 1006. The problem of electrolyte fluid 1038 forming a continuous column with receptacle 1008 and splashing into or out of receptacle 1008 may be reduced or prevented without electrolyte fluid flowing completely across wafer 1004. . For example, simply rotating the wafer 1004 to flow along a portion of the surface of the wafer 1004 toward the edge of the wafer 1004 before electrolyte fluid leaves the wafer 1004 will reduce or prevent undesirable effects. It may be.

III. Reduced edge over-polishing

In another aspect, an electropolishing method and apparatus is disclosed that reduces over-polishing at or near the edge of a wafer. In general, a portion of the metal layer at or near the edge of the wafer is polished faster than the portion of the metal layer on other areas of the wafer. Electrodes connected to the edge of the wafer increase the current density in the electrolyte fluid near the edge regions of the wafer resulting in increased polishing rates. In general, higher current densities and polishing rates near the wafer edge may be reduced by absorbing a portion of the current density through the electrolyte fluid with a conductor member, such as a ring or the like positioned near the edge of the wafer. The current density near the edge may be adjusted by charging the conductor member to change the amount of current absorbed so that the current density can be controlled to a significant extent.

Referring to FIG. 7, an exemplary apparatus and method for reducing overpolishing of an edge is shown. A flow of electrolyte fluid 7080 is applied from the nozzle 7054 to the wafer 7004. Wafer 7004 is rotated at a sufficient rotational speed to form a thin layer of electrolyte fluid 7081 capable of polishing a metal layer on wafer 7004. In general, when an electrode is connected to the edge of the wafer 7004, the metal layer near or near the edge of the wafer 7004 is polished faster than the metal on other areas of the wafer 7004 by a thin layer of electrolyte fluid 7081. . Thus, the metal layer near or near the edge of the wafer 7004 can be overpolished.

The chuck 7002 includes a conductor member 7114 that can reduce the amount of overpolishing at or near the edge of the wafer 7004. For example, wafer 7004 and conductor member 7114 may be connected and charged to power supply 7110 so that a portion of the polishing current in the thin layer of electrolyte fluid 7081 is absorbed by conductor member 7714. By absorbing a portion of the polishing current, the conductor member 7114 can reduce the polishing rate of the metal layer at or near the edge of the wafer 7004 and reduce or prevent overpolishing.

Conductor member 7114 may include a single ring located at or near the edge of wafer 7004. Alternatively, the conductor member may include two or more sections arranged near or near the edge of the wafer 7004. Conductor member 7114 may include metals or alloys, such as tantalum, titanium, stainless steel, and the like, as well as other conductor materials suitable for contact with electrolyte fluid 7081.

In addition, a wafer 7004 may be located between the wafer chuck 7002 and the conductor member 7114 as shown in FIG. For example, a robot arm or the like may position the wafer 7004 adjacent to the wafer chuck 7002 or between the wafer chuck 7002 and the conductor member 7114. Wafer chuck 7002 and conductor member 7114 may be in close proximity to hold wafer 7004 therebetween. Thus, the exemplary assembly can be configured to charge the wafer 7004 as well as additional members such as holders or positioners to align and maintain the wafer chuck 7002 and conductor member 7714. It may also include an insulating member between).

The example apparatus shown in FIG. 7 may also include the other structure shown in FIG. 1A, but it should be understood that it has been omitted to illustrate a particular example. For example, protective covers 1006 (FIGS. 1A and 1B) as well as various pumps, nozzles, filters, and the like may be used in the exemplary apparatus.

8A shows another exemplary electrolytic polishing apparatus useful for reducing the polishing rate near the edge of a wafer. A chuck 8002 is shown having a conductor member 8214 that may reduce the amount of overpolishing at or near the edge of the wafer 8004. FIG. 8A is similar to FIG. 7 except that conductor member 8114 is separated from wafer 8004 by spacer element 8218. Spacer element 818 is, for example, an O-ring. Spacer element 8218 is polytetrafluoroethylene (commercially known as Teflon), polyvinyl chloride (PVC), polyvinylindene fluoride (PVDF), polypropylene, silicone rubber, Viton rubber, etc. It may be made of a material which is an electrical insulator and which is also resistant to acid and corrosion. Conductor member 8114 is connected to power supply 8112, and a second conductor member or electrode, such as spring member 8119, is connected to power supply 8210. As shown, the current flowing through the conductor member 8214 may be regulated or controlled by the power supply 8112 to control the polishing rate of the metal layer at or near the edge of the wafer 8004. Generally, as the amount of current absorbed by the bottom chuck 8214 increases, the polishing rate of the metal layer near or near the edge of the wafer 8004 increases.

The power supply 8112 may be an AC power supply or the like synchronized with the DC power supply, the main polishing power supply 8210, or the like. The AC power source may include a forward pulse power source and forward and reverse power sources. Moreover, power supply 8112 can be operated in a constant current mode, a constant voltage mode, or a combination of constant current and constant voltage, where the constant current mode is applied for some time of polishing and the constant voltage mode is another time of polishing. Is applied. A variable charge can be applied to the conductor member 8214 by replacing the power supply 8112 with a variable resistor (see, eg, FIG. 9A). Moreover, a variable resistor may be included between the conductor member 8214 and the spring member 8119.

Conductor member 8214 may similarly include metals or alloys, such as tantalum, titanium, stainless steel, and the like, as well as other conductor materials. In addition, the conductor member 8214 may include one or more sections located at or near the edge of the wafer 8004.

Therefore, in the exemplary electrolytic polishing apparatus, the charge applied to the wafer 8004 through the spring member 8119 and the conductor member 8214 can be controlled independently by each of the power sources 8210 and 8112. This makes it possible to better control the current density in the vicinity of the edge region of the wafer 8004 to control and reduce overpolishing of the edge region.

FIG. 8B is an enlarged view of the structure and connections formed of the conductor member 8214 and wafer 8004 of FIG. 8A. In particular, the conductor member 8214 is charged by the power source 8112 and spaced apart from the wafer 8002 by the spacer element 8218. Wafer 8004 is separately charged by power supply 8210 coupled to spring member 8119 located around the edge of wafer 8004. The spring member 8119 provides charge to the wafer 8004, which is distributed evenly around the wafer 8004 rather than a plurality of electrodes located around the edge of the wafer 8004, for example. Insulating member 8121 may be located between conductor member 8214 and spring member 8119 when separate charge is applied to conductor member 8214 and spring member 8119. The spring member 8119 may be formed as a coil spring formed in the ring (see eg FIG. 8C), but other cross sectional profiles, such as an elliptical cross sectional profile, are possible. In addition, any number of coil springs may be used depending on the application. The spring member may be formed from any electrically conductive material such as stainless steel, spring steel, titanium, or the like. The spring member 8119 may be formed of a corrosion resistant material or coated with a corrosion resistant material such as platinum, TiN, TaN, or the like.

The number of contact points formed between the wafer 8004 and the power supply can be changed by changing the number of coils in the spring member 8119. In this manner, the charge applied to the wafer 8004 may be distributed more evenly around the outer periphery of the wafer 8004. For example, a charge having about 1 to about 10 amperes for a 200 mm wafer is generally applied. Configuring spring member 8119 to form about 1,000 contact points with wafer 8004 reduces the charge to about 1 to about 10 milliamps per contact point.

However, it should be appreciated that the wafer 8004 may be charged by one or more electrical contacts. In addition, any means for distributing charge near the wafer 8004 may be advantageously used.

Shorting may occur if the spring member 8119 is exposed to the electrolyte when the conductor member 8214 is separated from the wafer 8004 by the spacer element 8218. Shorting of the spring member 8119 may reduce the uniformity of the polishing rate near the edge portion of the wafer 8004. Therefore, in one embodiment, the spacer element 8218 acts as a seal to isolate the spring member 8119 from the electrolyte. The spacer element 8218 may be formed of a corrosion resistant material such as a viton (fluorocarbon) rubber, a silicone rubber, or the like. In addition, the spacer element 8218 may have various shapes and structures, depending on the particular application.

8C shows an enlarged view of an example wafer chuck holder that may be used with an example electrolytic polishing apparatus useful for reducing the polishing rate near the edge of the wafer. An exemplary wafer chuck includes a body having a base section 8002 and a conductor member 8214 at the top of the body, where the wafer 8004 is held between the base section 8002 and the conductor member 8214 of the body. do. The wafer chuck may further include an upper holder (not shown) for securing or holding the wafer 8004 and the assembly together. In addition to the first conductor member 8214, the wafer chuck includes a second conductor member, such as a spring member 8119, for applying charge to the wafer 8004. In certain embodiments, the wafer chuck may further include a spacer element 8218 and an insulating member 8121 disposed between the base member 8002 and the conductor member 8214 included at the bottom of the body. However, it should be appreciated that in certain embodiments the spring member 8119 and spacer element 8218 may be omitted, for example, as shown in FIG. 7. In the case where the spring member 8119 is omitted, an electrode or the like may be included as the second conductor member for applying electric charge to the wafer 8004.

In this embodiment, the spring member 8119 is disposed between the wafer 8004 and the spacer element 8218. When pressure is applied to hold the conductor member 8214 and the base section 8002 together, the spring member 8119 is formed to maintain electrical contact to the wafer 8004. In addition, the spacer element 8218 protects the spring member 8119 from the electrolyte and, if desired, forms a seal that provides insulation between the spring member 8119 and the conductor member 8214 to form a conductor member 8214 and a wafer 8004. Formed between).

In general, semiconductor wafers are substantially circular in shape. Thus, the various components of the wafer chuck are shown to have a substantially circular shape. However, it should be appreciated that various components of the wafer chuck may have various shapes depending on the particular application and / or shape of the wafer. For example, the semiconductor wafer may have a conical shape in which parts of the wafer chuck are formed to coincide.

Another exemplary configuration of a wafer chuck assembly for holding an appropriate wafer and applying charge to the wafer in the apparatus and method described above is referred to herein during electrolytic polishing and / or electroplating of workpieces, issued June 19, 2001. US Pat. No. 6,248,222, entitled Method and Device for Holding and Positioning Semiconductor Workpieces.

9A illustrates another exemplary electrolytic polishing apparatus useful for reducing the polishing rate near the edge of a wafer. In particular, wafer chuck 9002 includes conductor member 9314, which may reduce the amount of overpolishing at or near the edge of wafer 9004 as described above. FIG. 9A is similar to FIG. 8A except that the conductor member 9314 includes an insulating ring 9215 and a conductor ring 9316 formed within the insulating ring 9115. The insulating ring 9315 may include an insulating material that does not cause corrosion such as plastic, ceramic, or the like. Conductor ring 9316 may comprise a metal or alloy, such as platinum, tantalum, titanium, stainless steel, and the like. Conductor ring 9316 may be connected to power supply 9110 via a variable resistor 9112 or the like. Additionally, spacer elements 9918, such as O-rings, may be used to prevent the electrolyte from contacting portions of wafer 9004 that are connected to power supply 9210 via one or more electrodes. It can be located between (9004). Also, a spring member or the like (not shown) may be included to more evenly distribute the charge on the wafer 9004.

The example device of FIG. 9A allows a smaller amount of conductor material to be used with the conductor member 9314. This makes the device cheaper, lighter and consumes less power during operation. In addition, compared to the conductor members 8214, 8A, 8B, the less surface area of the conductor members 9115 allows for better control of the current density in the edge region of the wafer 8004. Also, the configuration of FIG. 9A (and FIG. 7) may be advantageously used in conjunction with the configuration of FIGS. 7 and 8A-8C.

9B shows an enlarged view of the electropolishing apparatus of another embodiment. 9B includes an insulating member 9121 formed with a conductor member 9314 formed below the conductor member 9914, ie, on the side opposite the wafer 9004. In addition, the wafer assembly is configured such that the metal layer 9005 on the wafer 9004 is charged near the edge via the conductor spacer element 9918.

Therefore, as can be seen in FIG. 9B, part of the current I ₁ flows into the metal layer 9005 and the second part I ₂ of the current when the electrolyte fluid 9080 is directed near the edge of the wafer 9004. Flows into the conductor member 9314. An insulating member (9121) formed in the lower portion of the conductor member (9114) acts to reduce the current I ₂ increases the current I ₁ flows in the metal layer (9005). Therefore, the mutual thickness of the insulating member 9121 and the conductor member 9314 may be adjusted to correspondingly adjust the currents I ₁ and I ₂ .

Ⅳ. Method of electropolishing separated metal layer on wafer

The metal layer formed on the wafer may be separated during the electropolishing process. For example, there may be one or more discontinuous metal regions on the surface of the wafer. When this phenomenon occurs, certain separations of the metal layer may be isolated from the edge of the wafer where the electrodes are located. In this case, conventional electrolytic polishing methods cannot effectively polish these separated sections because the electrodes do not charge the separated metal layer. In one exemplary method, by rotating the wafer at a sufficient rotational speed with a conductor member disposed around the separator of the metal layer, a thin layer of electrolyte fluid may form on the separator and be in contact with the conductor member. A thin layer of electrolyte fluid and conductor ring allows the separator to be electropolished.

As shown in FIGS. 11A and 11B, the metal layer 11150 is separated, for example, during the polishing process. The separator of the metal layer 11150 is not connected or positioned at the edge of the wafer 11004 to which an electrode (not shown) is connected to the power supply 11110. Since the separator of metal layer 11150 is not located at the edge of wafer 11004 or is not connected to these edges by metal, current cannot be connected to the electrode through the separator at the edge of wafer 11004. Therefore, conventional polishing methods, such as immersing the wafer in a polishing bath, are generally not effective for polishing such separations.

For example, the isolation of the metal layer 11150 of the metal layer may include an exposed portion of the barrier layer that remains on the untrenched portion of the semiconductor device after the copper layer is polished. In addition, the separation of the metal layer 11150 may be a result of non-uniform polishing or over polishing in the edge region, for example.

Referring to FIG. 11B, an exemplary electrolytic polishing apparatus for electropolishing the separation of metal layer 11150 on wafer 11004 is shown. The system includes a chuck 1102, an actuator 11000, a fixed nozzle 11054, and a power supply 1111. When the fixed nozzle 11054 applies the flow of electrolyte fluid 11080 to the wafer 11004, the actuator 11000 flows across the surface of the wafer 11004 as the electrolyte fluid 11080 is described above, and the metal layer The chuck 11002 can be rotated to form a thin layer 11081 that extends over the separator portion 11150. For example, wafer chuck 1102 may be rotated at a speed in the range of about 100 rpm to about 2000 rpm, preferably about 1500 rpm, for a 300 mm diameter wafer. The thin layer 11081 provides a path across the separation of the metal layer 11150 to allow a current to flow between the flow of the electrolyte fluid 11080 and the conductor member 11114 of the chuck 11002. This current allows the device to electrically polish the isolated separation of metal layer 11150 on wafer 11004.

Additionally, the exemplary device shown in FIG. 11B may be part of a larger electrolytic polishing assembly, such as the assembly shown in FIG. 1A. For example, a shroud (FIG. 1) may be included to prevent splashing, non-uniform polishing, or disruption of the polishing flow of electrolyte fluid 1038. Also, various exemplary embodiments of the conductor member 11114 described above in connection with the reduction of edge polishing may be used in connection with the apparatus of FIG. 11B.

FIG. 12 illustrates another system that can be used to electropolish a separation of a metal layer on a wafer 12004. FIG. 12 is similar to FIG. 11 except that the actuators 12180 and 12182 can move the nozzle 12054 along the x-direction while the actuator 12000 rotates the chuck 12002 in a fixed position.

11B and 12 show a system in which the chuck or nozzle moves along the x-direction, it should be appreciated that the chuck and nozzle may be moved in a variable direction depending on the particular application.

Ⅴ. Metal concentration measurement and termination detection control

One factor in achieving a more consistent and acceptable polishing quality of the wafer in mass production is to control the concentration of metal in the electrolyte fluid feed used to polish the wafer. When the metal concentration in the electrolyte fluid feed reaches a predetermined value, the electrolyte fluid can be very active even when no current is applied. This may cause chemical etching or corrosion of the wafer during the post-electropolishing process. Therefore, it is desirable to monitor and adjust in real time the metal concentration in the electrolyte fluid during process operation.

Termination detector sensors also generally employ an optical detector that measures through the electrolyte fluid. The measurement result therefore depends at least in part on the optical properties of the electrolyte fluid. However, the optical properties of the electrolyte fluid may vary over time depending on the concentration of the metal dissolved in the electrolyte fluid as well as other factors such as contaminating particles, hydrogen gas bubble formation in the electrolyte fluid, and the like. Therefore, because the optical properties of the electrolyte fluid change during process operation, the measurement results from the termination detector can be adjusted to increase the accuracy of the termination detection measurements.

10A illustrates an example system that may be used to measure metal concentration in a feed of electrolyte fluid 10038, such as an electrolyte fluid reservoir (FIG. 1A), and the like. The example system includes a fiber probe 10102, an optical fiber sensor 10104, and a reflector 10100. The fiber probe 10102 and the reflector 10100 are immersed in the electrolyte fluid 10038, and the fiber probe 10102 has light emitted from the fiber probe 10102 with respect to the reflector 10100 by the reflector 10100. The probe 10102 may be positioned in a reflective manner with maximum luminous intensity. For example, the fiber probe 10102 may be positioned to emit light in a direction perpendicular to the surface of the reflector 10102, as shown in FIG. 10A.

In addition, the distance H between the reflector 10100 and the fiber probe 10102 may be effective for accurate measurement of the metal concentration in the electrolyte fluid. Thus, the distance H can be selected such that the luminous intensity received by the optical sensor 10104 becomes a maximum when the metal concentration achieves a maximum concentration in the feed of electrolyte fluid 10038. It should be appreciated that other paths between the optical sensor 10104 and the reflector 10100 may be selected, including paths with multiple paths and multiple reflectivities, depending on the application and the desired path length. The fiber probe 10102 may be positioned outside the fluid reservoir while having a path across a portion of the electrolyte fluid 10038. In addition, an optical sensor positioned to detect the light intensity received by the optical sensor 10104 may replace the reflector 10100.

In general, the color of the electrolyte depends on the type and concentration of metal ions dissolved in the electrolyte. For example, copper ions in phosphoric acid (H ₃ PO ₄ ) have a blue color. Additionally, the intensity of light passing through the electrolyte fluid may collapse depending on the color of the electrolyte fluid. In general, as the concentration of metal ions in the electrolyte fluid increases, the collapse of luminosity increases.

For the system shown in FIG. 10A, the relationship between the metal concentration in the electrolyte fluid and the brightness collapse is tabled as follows for the particular metal and electrolyte fluid used with the system.

Metal concentration (% by weight) Luminosity collapse 0 Y1 0.2 Y2 0.4 Y3 0.6 Y4 0.8 Y5 1.0 Y6

The tabled information may be stored in computer 10105. Using the tabulated information, the computer can automatically calculate the metal concentration in the electrolyte fluid based on the brightness detected by the optical sensor 10104 by using interpolation, rounding, or other approximation. Although a predetermined value is listed in the table for metal concentration (% by weight), a predetermined value can be used and a predetermined number of values can be used.

The color of light emitted by the fiber probe 10102 may be selected to increase the sensitivity of the measurements detected by the optical sensor 10104. In particular, the color of light emitted by the fiber probe 10102 may be different from the color of the metal ions in the electrolyte fluid feed to increase the sensitivity to certain metal ions. For example, for copper ions in a phosphoric acid feed, the emission of red light provides higher sensitivity to copper ion concentrations than the emission of green light, and the emission of green light provides higher sensitivity than emission of blue light. . However, for certain colors of metal ions in the electrolyte fluid, white light may be emitted.

10A illustrates another aspect of the example system described above that may be used to remove metal ions from an electrolyte fluid 10038 feed. The system further includes two electrodes 10028 and 10029, and a power supply 10030. When the optical sensor 10104 measures when the metal ion concentration in the electrolyte fluid 10038 feed reaches the first set point, the computer 10105 applies a voltage to remove the metal ions from the electrolyte fluid feed. The power supply 10030 may be instructed to apply to 10028 and 10029. When voltage is applied to electrodes 10028 and 10029, metal ions from the electrolyte fluid 10038 feed begin to plate on electrode 10029. When the optical sensor 10104 detects when the metal ion concentration falls below the second set point, the computer 10105 may apply a voltage to the electrode 10028 and to stop the removal of metal ions from the electrolyte fluid 10038 feed. The power supply 10030 may be instructed to stop applying to 10029. In this way, the concentration of metal ions in the electrolyte fluid 10038 feed can be maintained between the first and second setpoints, for example, during the electropolishing process.

Concentration values of the metal ions in the electrolyte fluid 10038 may also be used to assist the termination detector 1016 (FIGS. 1A, 1B). Termination detector 1016 may be used to determine the metal layer thickness on wafer 1004. The information may be used by the electropolishing apparatus to determine whether to continue or stop the electropolishing process on a particular area of the wafer 1004. The information may also be used to determine the appropriate polishing rate. Termination detector 1016 may include various sensors, such as ultrasonic sensors, optical sensors, electromagnetic sensors, and the like. Using electrolyte fluid 1038 as the medium for transmitting and measuring signals increases measurement accuracy since air to the media interface, for example electrolyte 1038, need not be considered. However, if the characteristics of the electrolyte fluid 1038 affecting the sensor change, the measurement may not be accurate over time. Therefore, the measurement of the termination detector may be improved by considering the changing characteristics of the electrolyte fluid 1038.

10B shows another exemplary system for monitoring optical properties of an electrolyte fluid, which may be used, for example, to adjust endpoint detection measurements. FIG. 10B is similar to FIG. 10A except that the second optical sensor 10204 and the optical fiber 10202 are included. Optical sensor 10104, optical fiber 10102 and reflector 10100 operate in a similar manner as described with reference to FIG. 10A. The second optical sensor 10204 and the optical fiber 10202 also operate similarly to the optical sensor 10104 and the optical fiber 10102, while the optical sensor 10204 and the optical fiber 10202 have other optical properties of the electrolyte fluid. Measure For example, during the electropolishing process, hydrogen bubbles are often formed on the electrodes. Bubbles may adversely affect the termination detector by diffracting and reducing the strength of the measurement beam in the electrolyte fluid. The reduction in intensity may affect the measurement of metal ion concentration, but the metal ion concentration can be accurately determined by using multiple detectors that are sensitive to different properties.

In the example of determining the optical properties of the electrolyte fluid due to the bubbles, the color of light emitted by the fiber probe 10202 may be selected to increase the sensitivity of the measurements detected by the optical sensor 10204. In this case, the color of the light emitted by the fiber probe 10202 may be selected to be the same as the color of the metal ions in the electrolyte fluid feed to increase the sensitivity to the bubble and reduce the sensitivity to the metal ions. For example, for copper in a phosphate feed, the emission of blue light provides higher sensitivity to bubbles and lower sensitivity to copper ions than the emission of white, and the emission of white is more efficient than emission of red. It provides higher sensitivity to bubbles and lower sensitivity to copper ions.

Additionally, the intensity of red light from the fiber probe 10102 will be reduced due to certain bubbles in the electrolyte fluid so that the measurement of copper ion concentration will not be accurate. However, the second optical sensor 10204 will exhibit a reduced portion of sensitivity due primarily to the bubble rather than the copper ion concentration since the sensitivity of the fiber probe 10202 is chosen so as not to be sensitive to the copper ion concentration. Therefore, the sensitivity reduction of the red light may be determined by considering the portion due to the bubble determined by the second optical sensor 10204. In addition, the termination detector (FIG. 1A) may be able to correct the optical properties of the electrolyte fluid from the computer 10105 and to accurately measure the metal thickness on the wafer 1004 (FIG. 1A). Therefore, the second optical sensor 10204 may increase the precision of the termination detector measurement and the metal ion concentration measurement.

It should be appreciated that any number of sensors may be used to measure various properties of the electrolyte fluid. Various characteristics, such as optical characteristics, may be stored and used to adjust or determine termination detector measurements and the like.

Ⅵ. Nozzle configuration

According to another aspect of the invention, an exemplary method and apparatus for electropolishing a metal film on a wafer utilizes nozzles of multiple sizes with different polishing rates. In general, large nozzles allow higher polishing rates of metal films, eg copper, formed on the wafer and smaller nozzles form lower polishing rates. Therefore, a large nozzle is used for rough polishing of the metal layer and then a small nozzle is used to more accurately control the electropolishing process. Therefore, multiple nozzles are advantageous for polishing more precisely different areas of the wafer. However, because of the limited space in the clean room, for example, an apparatus with multiple nozzles is preferably compact. Therefore, an exemplary apparatus having many nozzles configured in a rotating nozzle holder allows the use of multiple nozzles in tight spaces.

13A, 13B, 13C, 13D, and 13E illustrate exemplary electropolishing assemblies that include multiple rotary nozzle assemblies. 13A-13E are similar to FIGS. 1A-1E except that a rotary nozzle 1012 with multiple nozzles positioned around the optical termination detector 1016 and an eddy current thickness / termination detector 1009 are added. Do. As shown by the arrows in FIG. 1A, the rotary nozzle 2012 may rotate and position nozzles 1014 of various sizes and / or shapes to direct the flow of electrolyte fluid 1038 to the wafer 1004. . Thus, pump 1018 directs electrolyte fluid 1038 to nozzle 1010 and single nozzle 1014 of termination detector 1016, while electrolyte 1038 in FIG. 1A is directed to each individual nozzle used herein. Is oriented.

Termination detector 1009 may operate to measure the thickness of a metal film formed on wafer 1004. Detector 1009 may measure the thickness of the metal film before, during and after the electropolishing process. In one exemplary method, termination detector 1009 is used to determine the thickness of a metal film across wafer 1004 prior to electropolishing using, for example, an edge current termination detector. The metal film thickness may then be used to control the local polishing rate for various locations on the wafer 1004 by controlling the current density and / or flow profile. The distance between the terminator detector 1009 and the wafer 1004 is for example in the range of about 5 microns to about 1000 microns. The film thickness for the entire wafer may be determined by rotating the wafer 1004 and moving the chuck 1002 in the horizontal direction while allowing the termination detector 1009 to scan the entire surface of the wafer 1004. However, it should be understood that termination detector 1009 may alternatively scan fixed wafer 1004.

The rotary nozzle 2012 may then rotate to select a predetermined nozzle 1014 depending on the portion of the wafer 1004 being polished, the metal film thickness, and the like. For example, larger nozzles may be used in areas where the metal layer is thicker, and smaller nozzles may be used in areas where the metal layer is thinner. The inclusion of many nozzles of various sizes and profiles in a simple and compact electropolishing assembly that may be interchanged quickly and easily improves the accuracy of polishing.

Referring to FIG. 14A, a cross sectional view of an exemplary multi-spinning nozzle holder 2012 is shown. Rotary nozzle holder 2012 holds nozzle 2014. The drive means 2070 rotates the rotary nozzle 2012 through a drive joint 2068 which positions the new nozzle to direct the flow of electrolyte fluid. The o-ring 2066 seals the drive joint 2068, for example. The drive means 2070 may be a stepper motor, a servomotor, a hydraulic (compressed gas or liquid) drive rotation means, or the like. The nozzle 2014 in the rotary nozzle holder 2012 includes an electrode 2056, which may be electrically connected to an external power supply 1040 (FIG. 13A) via a current supply penetration 2062. Rotary nozzle holder 2012 lies on plate 2084, which is sealed with chamber 1008 by o-ring 2072 and bolt 2074.

The nozzle holder 2012 may be made of plastic, such as PVC, PVD, TEFLON, polypropylene, or the like, or may be coated with a generally insulator and non-corrosive material. The nozzle 2014 may be made of tantalum, titanium, platinum, stainless steel, or the like.

FIG. 14C illustrates an example process for electropolishing a metal film from wafer 1002 using the apparatus of FIG. 14A. In block 1 the metal film thickness profile is determined by the termination detector 1009 moving in, for example, the x-direction when the wafer 1004 is rotated as described above. In block 2, the metal film can be initially polished at a high polishing rate using a large nozzle 2014. After the high polishing rate, the nozzle holder 2012 may be rotated at a lower polishing rate using a smaller nozzle 2014 at block 3. The metal thickness profile remaining after initial polishing at block 1 and / or block 2 may be determined at block 4 using termination detector 1009, for example an eddy current termination detector, an optical termination detector, or the like. Based on the residual metal thickness profile determined in block 4, the polishing current is used to polish thick film positions at higher speeds, to polish thin film positions at lower speeds, and to stop polishing at zero film thickness positions. It can also be adjusted or adjusted at. The polishing current may be adjusted, for example, by the use of different nozzles 2014 and / or by the change of charge supplied by the power supply. In block 6, the measurement of the thickness profile is repeated, ie block 4 is repeated. The polishing process may stop when the thickness of the metal layer reaches a preset value. However, if the thickness of the metal does not reach the preset value, block 5 may be repeated until the desired thickness is achieved.

It should be appreciated that numerous modifications and variations are possible in the process described with reference to FIG. 14C. In addition, many other processes may be used with the example apparatus of FIG. 14A.

Referring to FIG. 14B, another exemplary multi-spinning nozzle assembly is shown. The rotary nozzle assembly shown in FIG. 14B is similar to FIG. 14A except that the drive joint 2068 has been replaced with magnetically coupled joints 2078 and 2082. An advantage of using magnetically coupled joints 2078 and 2082 is that the drive joint 2078 is not directly connected to the nozzle holder 2012 and the o-ring 2066 of FIG. 14A may be omitted. This reduces the case where electrolyte fluid 1038 may leak into the drive joint 2068. Therefore, it should be appreciated that various ways of coupling the drive joint 2068 to the rotary nozzle 2012 are possible.

Referring to FIG. 15, an exemplary linear movable multi nozzle assembly is shown. The linearly movable multi-nozzle assembly operates similarly to the rotary nozzle 2012 of FIGS. 13A-13E except that the nozzle moves linearly as opposed to the rotary movement. The linearly movable multi-nozzle assembly includes nozzles 3054, 3222, and 3226 that include electrodes 3056, 3220, and 3224, respectively. The three nozzles 3054, 3222, and 3226 may be configured to have different profiles, eg, different diameters, to provide different polishing rates.

The nozzles 3054, 3222, and 3226 are movable in the horizontal direction, ie, in the x-direction, through the nozzle holder 3180 and the movement guide 3318. Electrodes 3056, 3220, and 3224 are also connected to power source 3110 via electrical penetrations (not shown). Electrolyte fluid 3080 is supplied to nozzles 3054, 3222, and 3226 through nozzle holder 3180. As described with reference to FIG. 14C, different size nozzles 3054, 3222, and 3226 may be used interchangeably during the electropolishing process to remove the metal film disposed on the wafer 1004. In general, when a metal film is thick, a large nozzle is used to polish the metal film at a higher polishing rate, and when the metal film is thin or a small amount of metal is desired to be removed, the small nozzle may lower the metal film to a lower polishing rate It can also be used to polish in.

16A-16E illustrate an example electrolytic polishing assembly that includes multiple rotary nozzle assemblies. 16A-16E are similar to FIGS. 13A-13E with the addition of a linear moveable base 4180 and a movement guide 4142 with rotary nozzles 4012 and 4014 mounted thereon.

In particular, a rotary multiple nozzle 4014, an optical termination detector 4016, and an eddy current thickness / termination detector 4060 are mounted on the linearly movable base 4180. The linearly movable base member may be moved along the movement guide 4142 in the horizontal direction, ie in the x-direction. The assembly allows multiple nozzles to be included in a compact space.

The structure and operation of the multiple nozzle 4014 is similar to that shown in Figs. 14A and 14B, but structures such as rotary drive means, drive joints, current supply penetrations, and electrolyte supply penetrations are omitted for illustrative purposes. .

Iii. Nozzle Self-Cleaning Process

According to another aspect of the invention, an exemplary process for self-cleaning an electropolishing nozzle is described. The metal dissolved in the electrolyte fluid during a typical electropolishing process may be plated onto the nozzle electrode. The plated metal changes the shape and / or direction of the electrolyte fluid by limiting or modifying the opening of the nozzle. The change in flow shape changes the current density of the flow and eventually the polishing rate of the electropolishing apparatus. The nozzle may be deplated or cleaned by applying a reverse voltage to the nozzle to dissolve the metal ions back into the electrolyte solution. For example, the metal may be plated on another nozzle, sacrificial material, or the like.

Referring again to FIGS. 1A-1E, the metal of the metal layer polished from the wafer 1004 is dissolved in the electrolyte fluid 1038 so that a portion of the dissolved metal is plated on the nozzle electrodes 1056 and / or 1060. To remove the metal from the nozzle electrodes 1056 and / or 1060, a reverse voltage may be applied to the nozzle electrodes 1056 and / or 1060. DC or AC power sources can be used to apply the reverse voltage. In one exemplary process, a reverse voltage is applied to dissolve the metal accumulation in the electrolyte fluid. In another exemplary process, a reverse voltage is applied to plate the metal deposits on the treatable wafer. In another embodiment, a reverse voltage is applied to plate the metal deposits on the block.

A. Dissolving metal buildup in electrolyte fluid using a DC power source

Referring to FIG. 1A, metal buildup on nozzle 1012 may be polished using a DC power source and dissolved into electrolyte fluid 1038. More specifically, line C is connected to line b and line B is connected to line a such that nozzle electrode 1056 (FIGS. 1B-1E) serves as an anode and nozzle electrode 1060 serves as a cathode. Electrolyte fluid 1038 is used to form an electrical circuit between electrodes 1056 and 1060 that allows metal deposits on nozzle 1012 to be removed from nozzle 1012 and dissolved in electrolyte fluid 1038. 1014). A portion of the metal dissolved in electrolyte fluid 1038 may be plated on nozzle 1014.

Although the process seems to move metal from only one nozzle to plate the metal to another nozzle, most of the metal removed from the nozzle 1012 is dissolved in the electrolyte fluid 1038. The metal concentration in the electrolyte fluid 1038 for the exemplary electrolytic polishing process is generally low, for example 3 wt% or less, such that electropolishing is not performed by the chemicals of the electrolyte solution 1038 but by the electrodes 1012 and 1014. It is driven by electrically charging it. Therefore, the amount of metal polished from the nozzle 1012 is greater than the amount of metal plated on the nozzle 1014. For example, 10 metal ions may be removed from the nozzle 1012 for one metal ion plated on the nozzle 1014 such that most of the metal ions are dissolved in the electrolyte fluid 1038.

With continued reference to FIG. 1A, the process may be reversed so that metal deposits on the nozzle 1014 are polished using a DC power source and dissolved in the electrolyte fluid 1038. More specifically, line B is connected to line b and line C is connected to line a such that nozzle electrode 1060 (FIGS. 1B-1E) acts as an anode and nozzle electrode 1056 acts as a cathode. Electrolyte fluid 1038 may be supplied through nozzles 1012 and 1014 to form an electrical circuit that allows metal deposits on nozzle 1014 to be removed from nozzle 1014 and dissolved into electrolyte fluid 1038. . Again, a portion of the metal dissolved in electrolyte fluid 1038 may be plated on nozzle 1012.

By repeating the above process, ie by reversing the voltage for each nozzle used in the apparatus, the nozzles can be cleaned. In one exemplary process, the nozzle is quickly cleaned by electropolishing the continuous wafer by the first deplating nozzle 1012 and the plating nozzle 1014, followed by the deplating nozzle 1014 and the plating nozzle 1012. do. Both nozzles are effectively cleaned because most of the metal is dissolved in the electrolyte fluid 1038 instead of being plated on the opposite nozzle as described above.

2 and 3 show two exemplary structures of nozzles 1012 and 1014 during the cleaning process. The nozzles 1012 and 1014 are positioned adjacent to each other and the electrolyte is allowed to flow through the nozzles 1012 and 1014 to form a path or film of electrolyte fluid therebetween. As shown in FIG. 3, when the nozzles 1012 and 1014 are located closer together, two films or two paths of electrolyte fluid 1038 flowing between the nozzles 1012 and 1014 may be combined to form a single path. . The single path reduces the length of the electrical circuit, increasing the efficiency of the metal deposit removal process. It should be appreciated, of course, that the exemplary process may be employed with more than one nozzle.

B. Plating Metal Accumulation on Wafers Using a DC Power Source

Referring to FIG. 1A, metal deposits on the nozzles 1012 are polished and plated onto the wafer 1004 using a DC power source in accordance with another exemplary process. More specifically, line A is connected to line b and line B is connected to line a such that wafer 1004 acts as a cathode and nozzle electrode 1056 (FIGS. 1B-1E) acts as an anode. Electrolyte fluid 1038 may be supplied to wafer 1004 through nozzle 1012 to form an electrical circuit that allows metal deposits on nozzle 1012 to be plated onto wafer 1004. Wafer 1004 may be discarded after metal buildup on nozzle 1012 is removed.

Similarly, referring to FIG. 1A, metal deposits on nozzle 1014 may be polished using a DC power supply and plated onto wafer 1004. More specifically, line A is connected to line b and line C is connected to line a such that wafer 1004 acts as a cathode and nozzle electrodes 1060 (FIGS. 1B-1E) act as anodes. Electrolyte fluid 1038 may be supplied to wafer 1004 through nozzle 1014 to form an electrical circuit that allows metal deposits on nozzle 1014 to be plated onto wafer 1004. The nozzle 1012, or other nozzle, in the electropolishing process may be cleaned in parallel or in series with the nozzle 1014. Wafer 1004 may be discarded after metal buildup on nozzle 1014 is removed.

C. Plating metal deposits on blocks using a DC power source

Referring to FIG. 4, metal buildup 1057 on nozzle 1012 may be polished using a DC power supply and plated on block 1082 in accordance with another exemplary process. More specifically, line B is connected to line a and line D is connected to line a such that block 1082 acts as the cathode and nozzle electrode 1056 acts as the anode. Electrolyte fluid 1038 (FIG. 1) is supplied through and blocked through nozzle 1012 to form an electrical circuit through electrolyte fluid 1038 that allows metal deposits on nozzle 1012 to be plated on block 1082. And may be allowed to contact 1082. Block 1082 may be discarded after metal buildup on nozzle 1012 has been removed, or when convenient.

Similarly, referring to FIG. 4, metal buildup 1057 on nozzle 1014 may be polished using a DC power supply and plated on block 1082. More specifically, line C is connected to line a and line D is connected to line b such that block 1082 acts as the cathode and nozzle electrode 1060 acts as the anode. Electrolyte fluid 1038 (FIG. 1) is fed through nozzle 1014 and contacts block 1082 to form an electrical circuit that may allow metal deposits on nozzle 1014 to be plated on block 1082. May be allowed to. Block 1082 may be discarded after metal buildup on nozzle 1014 has been removed, or when convenient. Also, electrodes 1056 and 1060 may be cleaned in series or in parallel.

D. Remove metal buildup using AC power source

In another exemplary nozzle cleaning process, instead of a DC power source, an AC power source may be used with the structure to remove metal buildup from the nozzles 1012 and 1014. In particular, an AC power source is used to dissolve the metal deposits in the electrolyte fluid, plate the metal deposits on the discarded wafer, or plate the metal deposits on the block or other sacrificial material.

Removal of metal deposits from nozzles using an AC power source is more effective when the metal concentration in the electrolyte fluid is reduced. Thus, the metal concentration may generally range from about 0.1% to about 5% by weight, preferably up to about 0.5% by weight during the removal process.

Iii. Nozzle form

In certain exemplary embodiments described above, nozzles of various types may be advantageously used. Different types of nozzles, for example different sizes, profiles, cross sectional shapes, etc., provide different polishing properties and may be advantageously used depending on the particular application. For example, as can be seen in FIG. 1B, an exemplary electropolishing apparatus may include two different size nozzles 1012 and 1014 that may be used for electropolishing different sections of the wafer 1004. .

Additionally, FIGS. 5A-5H illustrate various exemplary nozzles of various shapes and structures. The shape of the nozzle, for example the channel and the distal end, can change the profile of the electrolyte fluid flowing from the nozzle, the current density in the flow of the electrolyte fluid, and the like. 5A-5E illustrate various nozzle structures and shapes including insulator 5054 and electrodes 5056. 5F-5H illustrate nozzles without insulators. Curved electrode 5056 prevents electrical peaks at sharp points of the electrode, helping to form a more uniform current density in the flow of electrolyte fluid. FIG. 5H shows a nozzle that includes an electrode 5056 and a rod 5058 positioned around the center of the nozzle to increase the surface area of the electrode and to form a more uniform current density.

For each nozzle described above, electrode 5056 may comprise a metal or alloy, such as tantalum, titanium, stainless steel, or the like. Additionally, insulator 5054 may include plastics such as PVC, PVD, Teflon, or the like, or ceramics such as Al ₂ O ₃ , ZrO ₂ , SiO ₂ , and the like. Therefore, since metals and alloys are generally easier to form in various forms than plastics and ceramics, nozzles having curved or tapered electrodes and insulators having straight shapes can be less expensive to manufacture than other forms. Moreover, as shown in FIGS. 5F, 5G, and 5H, a nozzle with only one electrode 506 may have a simple shape and a larger surface area. Additionally, the nozzle shown in FIG. 5H includes a rod 5058 as part of the electrode 5056, which provides a larger surface area for the electrode and more evenly across the electrolyte fluid 1038 (FIG. 1A) flowing from the nozzle. Dislocations may be distributed. More uniformly distributed dislocations result in more uniform electrolytic polishing of wafer 1004.

6A and 6B show another exemplary nozzle having an insulator 6054, an electrode 6056, and a conductive internal structure 6086. Internal structure 6086 includes a metal or alloy, such as tantalum, titanium, stainless steel, and the like. Additionally, the internal structure 6068 includes multiple channels that increase the surface area of the electrode and can distribute the potential more evenly across the nozzle 6056. The size of the channel may range from about 0.1 mm to about 10 mm, depending on the diameter of the nozzle and the particular application. Preferably, the size of each nozzle may be about 1/10 of the nozzle diameter.

The channels may be formed in various cross sectional shapes as shown in FIGS. 6B-6I. For example, the channel may be square, fibrous, straight slot, metal rod, wave slot, rectangular, honeycomb, or the like. In addition, although a particular cross sectional shape is shown in FIGS. 6B-6I, the channel may be formed in any cross sectional shape such as triangle, polygon, ellipse, and the like.

The foregoing description is for illustrative purposes only and is not intended to limit the scope of the invention. It will be apparent to those skilled in the art that numerous modifications and variations are possible without departing from the scope of the present invention. For example, different exemplary electropolishing apparatuses, such as shrouds, conductor members, various nozzles, termination detectors, and the like, may be used together in a single assembly or separately to enhance conventional electropolishing apparatus. Accordingly, the invention should not be limited by the detailed description, but rather by the claims.

Claims (182)

As an electrolytic polishing apparatus for wafers, A wafer chuck holding the wafer, An actuator for rotating the wafer chuck, A nozzle configured to electropolize the wafer, and A protective cover positioned about an edge of the wafer, Electrolytic polishing apparatus for wafers. The method of claim 1, The actuator is configured to rotate the wafer chuck at a rotational speed sufficient to allow an electrolyte fluid flow incident on the wafer to flow toward an edge of the wafer, Electrolytic polishing apparatus for wafers. The method of claim 2, The electrolyte fluid flows past an edge of the wafer and enters the protective cover, Electrolytic polishing apparatus for wafers. The method of claim 2, The wafer is directed downward and a flow of electrolyte fluid incident on the wafer flows to the edge of the wafer before falling off the surface of the wafer, Electrolytic polishing apparatus for wafers. The method of claim 1, The actuator is configured to vary the rotation of the chuck according to the portion of the wafer to be electropolished, Electrolytic polishing apparatus for wafers. The method of claim 5, wherein The actuator is configured to rotate the chuck at a higher speed when the electrolytic polishing portion of the wafer is close to the center Electrolytic polishing apparatus for wafers. The method of claim 1, The wafer chuck configured to move relative to the nozzle, Electrolytic polishing apparatus for wafers. The method of claim 7, wherein The protective cover is configured to move with the wafer chuck in relation to the nozzle, Electrolytic polishing apparatus for wafers. The method of claim 7, wherein Wherein the shroud and the wafer chuck are mechanically connected to move together with respect to the nozzle, Electrolytic polishing apparatus for wafers. The method of claim 1, The nozzle is configured to move in relation to the wafer chuck, Electrolytic polishing apparatus for wafers. The method of claim 1, The protective cover is located in the range of about 1 mm to about 10 mm from the edge of the chuck, Electrolytic polishing apparatus for wafers. The method of claim 1, The protective cover is located about 5 mm from the edge of the chuck, Electrolytic polishing apparatus for wafers. The method of claim 1, The side wall of the protective cover comprises an L-shaped cross section, Electrolytic polishing apparatus for wafers. The method of claim 1, Tapered sidewalls of the protective cover, Electrolytic polishing apparatus for wafers. The method of claim 1, The sidewall of the protective cover extends above or below the chuck; Electrolytic polishing apparatus for wafers. The method of claim 1, Wherein the protective cover comprises a plastic or ceramic material, Electrolytic polishing apparatus for wafers. The method of claim 1, The protective cover comprises a corrosion-resistant metal or alloy, Electrolytic polishing apparatus for wafers. The method of claim 1, The protective cover is coated with a material resistant to the electrolyte fluid, Electrolytic polishing apparatus for wafers. As an electrolytic polishing method of a semiconductor wafer, Electropolishing the wafer with a flow of electrolyte fluid, Rotating the wafer such that the electrolyte fluid entering the wafer flows across the wafer surface toward the edge of the wafer, and Positioning a shroud adjacent the edge of the wafer; Electrolytic polishing method of a semiconductor wafer. The method of claim 19, Wherein the wafer is rotated at a sufficient rotational speed so that electrolyte fluid incident on the wafer flows to the edge of the wafer without leaving the surface of the wafer, Electrolytic polishing method of a semiconductor wafer. The method of claim 19, The electrolyte fluid flows past an edge of the wafer and enters the protective cover, Electrolytic polishing method of a semiconductor wafer. The method of claim 19, Changing the rotation of the chuck in accordance with the portion of the wafer being electropolished; Electrolytic polishing method of a semiconductor wafer. The method of claim 22, The wafer is rotated at a higher speed when the electrolytic polishing portion of the wafer is close to the center, Electrolytic polishing method of a semiconductor wafer. The method of claim 19, Moving the wafer relative to the nozzle; Electrolytic polishing method of a semiconductor wafer. The method of claim 19, Further comprising moving the protective cover in relation to the nozzle, Electrolytic polishing method of a semiconductor wafer. The method of claim 19, Moving the protective cover and the wafer together with respect to the nozzle, Electrolytic polishing method of a semiconductor wafer. The method of claim 19, Further comprising moving the nozzle relative to the wafer, Electrolytic polishing method of a semiconductor wafer. As a wafer holding device, A body supporting the wafer and exposing one side of the wafer to a flow of electrolyte fluid, A first conductor member configured to apply charge to the wafer, and A second conductor member configured to be exposed to the flow of electrolyte fluid, Wafer holding device. The method of claim 28, Wherein the first conductor member is configured to be isolated from the flow of the electrolyte fluid, Wafer holding device. The method of claim 28, A charge is applied to the second conductor member, Wafer holding device. The method of claim 28, The charge applied to the second conductor member is different from the conductive charge applied to the wafer, Wafer holding device. The method of claim 28, The second conductor member is a ring, Wafer holding device. The method of claim 28, The second conductor member is located near the periphery of the wafer, Wafer holding device. The method of claim 28, The second conductor member comprises a metal, Wafer holding device. The method of claim 28, The second conductor member is in contact with the wafer, Wafer holding device. The method of claim 28, An insulating member is located between the wafer and the second conductor member, Wafer holding device. The method of claim 36, The insulating member forms a seal between the conductor member and the wafer, Wafer holding device. The method of claim 36, The insulating member comprises an o-ring, Wafer holding device. The method of claim 36, The insulating member comprises a synthetic rubber, Wafer holding device. The method of claim 28, Wherein the first conductor member comprises a spring member Wafer holding device. The method of claim 40, The spring member is configured to be in contact with an outer periphery of the wafer, Wafer holding device. The method of claim 40, The spring member comprises a spring, Wafer holding device. The method of claim 40, The spring member comprises a plurality of coil springs arranged around an outer periphery of the wafer, Wafer holding device. The method of claim 40, A second insulating member is inserted between the spring member and the second conductor member, Wafer holding device. The method of claim 28, One of the charges applied by the first conductor member and the charges applied by the second conductor member may vary with respect to each other, Wafer holding device. The method of claim 28, Further comprising a DC power supply configured to apply the charge, Wafer holding device. The method of claim 28, Further comprising an AC power supply configured to apply the charge, Wafer holding device. The method of claim 28, Wherein the second conductor member is located in an insulating member, Wafer holding device. 49. The method of claim 48 wherein The insulating member is a ring, Wafer holding device. The method of claim 28, One or more resistors for altering the charge applied to the wafer or the charge applied to the second conductor member; Wafer holding device. The method of claim 28, Wherein the second conductor member has an insulating coating layer, Wafer holding device. The method of claim 28, A second insulating member is located on one side of the second conductor member opposite the wafer, Wafer holding device. As a method of holding a semiconductor wafer during an electrolytic polishing process, Positioning the surface of the wafer within the flow of electrolyte fluid, Applying charge to the wafer with a first conductor member, and Applying an electric charge to the second conductor member, The second conductor member is configured to absorb current from the electrolyte fluid on the wafer surface, Method of holding a semiconductor wafer. The method of claim 53, wherein The second conductor member absorbs current near an edge of the wafer to reduce polishing rate, Method of holding a semiconductor wafer. The method of claim 53, wherein The wafer is rotated such that the electrolyte fluid flows toward an edge of the wafer, Method of holding a semiconductor wafer. The method of claim 53, wherein The second conductor member is located near an edge of the wafer, Method of holding a semiconductor wafer. The method of claim 53, wherein The second conductor member is a metal ring, Method of holding a semiconductor wafer. The method of claim 53, wherein Further comprising an insulation member located between the wafer and the second conductor member, Method of holding a semiconductor wafer. The method of claim 53, wherein The conductor member is located adjacent to the wafer, Method of holding a semiconductor wafer. The method of claim 53, wherein Adjusting one of the charges applied to the wafer and the charges applied to the second conductor member relative to one another; Method of holding a semiconductor wafer. The method of claim 53, wherein The charge is applied by a DC power supply, Method of holding a semiconductor wafer. The method of claim 53, wherein The charge is applied by an AC power source, Method of holding a semiconductor wafer. The method of claim 53, wherein The second conductor member is located in an insulating member, Method of holding a semiconductor wafer. The method of claim 53, wherein The insulating member is a ring, Method of holding a semiconductor wafer. An apparatus for monitoring the termination of an electrolytic polishing process of a metal layer formed on a wafer, A nozzle configured to electropolize the metal layer, A termination detector disposed adjacent the nozzle, A reservoir containing an electrolyte fluid and connected to the nozzle, A fluid detector disposed in the reservoir, The fluid detector measures a property of the fluid, and the termination detector is configured to measure wafer properties in view of the measured property of the fluid, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 66. The method of claim 65, Configured to terminate the electrolytic polishing process when the measured characteristic of the wafer reaches a target value, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 66. The method of claim 65, Wherein the nozzle and the termination detector are configured to move together to electropolise a separate portion of the wafer, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 66. The method of claim 65, The nozzle is configured as a fixed nozzle and the wafer is moved relative to the nozzle, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 66. The method of claim 65, Further comprising a wafer chuck configured to rotate the wafer, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 66. The method of claim 65, The fluid detector measures the concentration of metal ions in the fluid, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. The method of claim 70, And further comprising an electrode configured to remove metal ions from the electrolyte fluid when the metal ion concentration reaches a preset value and immersed in the electrolyte fluid, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. The method of claim 71 wherein The electrode is configured to stop removal of metal ions from the electrolyte fluid when the metal ion concentration reaches a second preset value, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 66. The method of claim 65, The fluid detector comprises an optical detector, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. The method of claim 73, wherein The optical detector comprises red light, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. The method of claim 73, wherein The optical detector comprises white light, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. The method of claim 73, wherein Further includes a reflector, The optical detector reflects light, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 66. The method of claim 65, The termination detector comprises an optical reflection detector, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 66. The method of claim 65, The termination detector comprises an ultrasonic detector, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 66. The method of claim 65, The termination detector comprises an electromagnetic detector, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 66. The method of claim 65, The termination detector comprises an eddy current detector, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 66. The method of claim 65, Further comprising a second fluid detector for measuring a second characteristic of the fluid, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 82. The method of claim 81 wherein The termination detector is configured to measure wafer characteristics in view of the second measured characteristic of the fluid, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 82. The method of claim 81 wherein The second fluid detector comprises an optical detector, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 82. The method of claim 81 wherein The optical detector comprises blue light, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 82. The method of claim 81 wherein The optical detector comprises white light, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. 82. The method of claim 81 wherein The optical detector detects bubbles in the electrolyte fluid, A device for monitoring the termination of an electropolishing process of a metal layer formed on a wafer. As a method of detecting termination of an electropolishing process of a wafer, Electropolishing the wafer using an electrolyte fluid, Measuring characteristics of the wafer using a termination detector, Measuring a characteristic of the electrolyte fluid using a fluid detector, and Evaluating a characteristic of the wafer measured by the termination detector in view of the characteristic of the fluid measured by the fluid detector, Termination detection method of the electropolishing process of the wafer. 88. The method of claim 87, The electrolytic polishing step is terminated when the measured characteristic of the wafer reaches a target value, Termination detection method of the electropolishing process of the wafer. 88. The method of claim 87, Wherein the termination detector and the nozzle are configured to move together to electropolise a separate portion of the wafer, Termination detection method of the electropolishing process of the wafer. 88. The method of claim 87, Moving the wafer with respect to the fixed nozzle; Termination detection method of the electropolishing process of the wafer. 88. The method of claim 87, Rotating the wafer with a wafer chuck; Termination detection method of the electropolishing process of the wafer. 88. The method of claim 87, Measuring the metal ion concentration of the fluid with the fluid detector, Termination detection method of the electropolishing process of the wafer. 92. The method of claim 92, Removing metal ions from the electrolyte fluid when the metal ion concentration reaches a preset value, Termination detection method of the electropolishing process of the wafer. 92. The method of claim 92, When the metal ion concentration reaches the second preset value, metal ions are no longer removed from the electrolyte fluid, Termination detection method of the electropolishing process of the wafer. 88. The method of claim 87, The fluid detector comprises an optical detector, Termination detection method of the electropolishing process of the wafer. 88. The method of claim 87, The optical detector comprises red light, Termination detection method of the electropolishing process of the wafer. 97. The method of claim 96, The optical detector comprises white light, Termination detection method of the electropolishing process of the wafer. 97. The method of claim 96, Further reflecting light from a reflector to the optical detector, Termination detection method of the electropolishing process of the wafer. 88. The method of claim 87, The termination detector comprises an optical reflection detector, Termination detection method of the electropolishing process of the wafer. 88. The method of claim 87, The termination detector comprises an ultrasonic detector, Termination detection method of the electropolishing process of the wafer. 88. The method of claim 87, The termination detector comprises an electromagnetic detector, Termination detection method of the electropolishing process of the wafer. 88. The method of claim 87, Further comprising measuring a second characteristic of the fluid, Termination detection method of the electropolishing process of the wafer. 103. The method of claim 102, The termination detector is configured to measure wafer characteristics in view of the second measured characteristic of the fluid, Termination detection method of the electropolishing process of the wafer. 103. The method of claim 103, Wherein the second property of the fluid is measured with a second detector, Termination detection method of the electropolishing process of the wafer. 103. The method of claim 102, The second fluid detector comprises an optical detector, Termination detection method of the electropolishing process of the wafer. 103. The method of claim 102, The second optical detector comprises blue light, Termination detection method of the electropolishing process of the wafer. 103. The method of claim 102, The second optical detector comprises white light, Termination detection method of the electropolishing process of the wafer. 103. The method of claim 102, The second optical detector detects bubbles in the electrolyte fluid, Termination detection method of the electropolishing process of the wafer. An electropolishing apparatus of a separated metal layer on a semiconductor wafer, A wafer chuck holding the wafer, A conductor member around the wafer chuck, A nozzle configured to direct a flow of electrolyte fluid to the surface of the wafer, and An actuator configured to rotate the wafer chuck at a rotational speed sufficient to form a thin film of electrolyte fluid across the surface of the wafer to electrically connect the separated metal layers; Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 112. The method of claim 109, The thin film of electrolyte fluid forms a path for conducting current between the electrolyte fluid and the conductor member, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 112. The method of claim 109, The wafer is directed downward and a flow of electrolyte fluid incident on the wafer flows to the edge of the wafer before falling off the surface of the wafer, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 112. The method of claim 109, The actuator is configured to vary the rotation of the chuck according to the portion of the wafer to be electropolished, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 112. The method of claim 112, The actuator is configured to rotate the chuck at a higher speed when the electrolytic polishing portion of the wafer is close to the center Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 112. The method of claim 109, The wafer chuck is configured to move the wafer relative to the nozzle, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 112. The method of claim 109, The nozzle is configured to move in relation to the wafer chuck, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 112. The method of claim 109, Further comprising a protective cover surrounding the wafer chuck, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 117. The method of claim 116 wherein The protective cover moves with the wafer chuck in relation to the nozzle, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 117. The method of claim 116 wherein Wherein the shroud and the wafer chuck are mechanically connected to move together with respect to the nozzle, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 117. The method of claim 116 wherein The protective cover is located in a range of about 1 mm to about 10 mm from an edge of the wafer chuck, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 117. The method of claim 116 wherein The protective cover is located about 5 mm from the edge of the chuck, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 117. The method of claim 116 wherein The side wall of the protective cover comprises an L-shaped cross section, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 117. The method of claim 116 wherein Tapered sidewalls of the protective cover, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 117. The method of claim 116 wherein The sidewall of the protective cover extends above or below the chuck; Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 117. The method of claim 116 wherein Wherein the protective cover comprises a plastic or ceramic material, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 117. The method of claim 116 wherein The protective cover comprises a corrosion-resistant metal or alloy, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. 117. The method of claim 116 wherein The protective cover is coated with a material resistant to electrolyte fluid, Electrolytic polishing apparatus of a separated metal layer on a semiconductor wafer. An electrolytic polishing method of a separated metal layer on a semiconductor wafer, Holding the wafer with a wafer chuck comprising a conductor member positioned around the wafer; Electropolishing the wafer with a flow of electrolyte fluid, and Rotating the wafer such that the electrolyte fluid incident on the wafer forms a thin film of electrolyte fluid on the surface of the wafer; A method of electropolishing of separated metal layers on a semiconductor wafer. 127. The method of claim 127, wherein Wherein the wafer is rotated at a sufficient rotational speed so that electrolyte fluid incident on the wafer flows to the edge of the wafer without leaving the surface of the wafer, A method of electropolishing of separated metal layers on a semiconductor wafer. 127. The method of claim 127, wherein Changing the rotation of the chuck in accordance with the portion of the wafer being electropolished; A method of electropolishing of separated metal layers on a semiconductor wafer. 131. The method of claim 129 wherein The wafer is rotated at a higher speed when the electrolytic polishing portion of the wafer is close to the center, A method of electropolishing of separated metal layers on a semiconductor wafer. 127. The method of claim 127, wherein Moving the wafer relative to the nozzle; A method of electropolishing of separated metal layers on a semiconductor wafer. 127. The method of claim 127, wherein Further comprising placing a shroud around the wafer chuck; A method of electropolishing of separated metal layers on a semiconductor wafer. 127. The method of claim 127, wherein The electrolyte fluid flows past an edge of the wafer and enters the protective cover, A method of electropolishing of separated metal layers on a semiconductor wafer. 127. The method of claim 127, wherein Further comprising moving the protective cover in relation to the nozzle, A method of electropolishing of separated metal layers on a semiconductor wafer. 127. The method of claim 127, wherein Moving the protective cover and the wafer together with respect to the nozzle, A method of electropolishing of separated metal layers on a semiconductor wafer. 127. The method of claim 127, wherein Further comprising moving the nozzle relative to the wafer, A method of electropolishing of separated metal layers on a semiconductor wafer. As an electrolytic polishing apparatus for wafers, A nozzle holder configured to maintain two or more nozzles adjacent to a supply line of electrolyte fluid, One or more of the nozzle holder and the supply line move relative to the other to connect one of the two or more nozzles to the supply line of the electrolyte fluid, Electrolytic polishing apparatus for wafers. 138. The method of claim 137, Further includes an actuator, The actuator is configured to rotate the nozzle holder to connect to one of the two or more nozzles, Electrolytic polishing apparatus for wafers. 138. The method of claim 137, Wherein the nozzle holder comprises an insulating material, Electrolytic polishing apparatus for wafers. 138. The method of claim 137, The nozzle holder comprises a material that does not corrode Electrolytic polishing apparatus for wafers. 138. The method of claim 137, The nozzle holder is made of plastic, Electrolytic polishing apparatus for wafers. 138. The method of claim 137, Wherein the nozzle holder and the one or more nozzles are integrally formed, Electrolytic polishing apparatus for wafers. 138. The method of claim 137, Wherein the two or more nozzles comprise two or more different profiles, Electrolytic polishing apparatus for wafers. 138. The method of claim 137, Further comprising a termination detector positioned adjacent the nozzle holder, Electrolytic polishing apparatus for wafers. 138. The method of claim 137, It further comprises a movable base, The nozzle holder is connected to the movable base, Electrolytic polishing apparatus for wafers. 145. The method of claim 145, The movable base is configured to move in a straight direction and the nozzle holder is configured to rotate, Electrolytic polishing apparatus for wafers. As an electrolytic polishing method of a semiconductor wafer, Providing a wafer, Providing an electrolyte fluid feed, Providing two or more nozzles mechanically connected to each other, Movably positioning one of the two or more nozzles in the electrolyte fluid feed to direct a flow of electrolyte fluid towards the wafer, Electrolytic polishing method of a semiconductor wafer. The method of claim 147, wherein The two or more nozzles are mechanically connected through a nozzle holder, Electrolytic polishing method of a semiconductor wafer. The method of claim 148, wherein Movably positioning one of the two or more nozzles includes rotating the nozzle holder, Electrolytic polishing method of a semiconductor wafer. The method of claim 148, wherein Movably positioning the nozzle comprises moving the nozzle holder in a straight direction, Electrolytic polishing method of a semiconductor wafer. The method of claim 147, wherein Wherein the two or more nozzles comprise two or more different nozzle profiles, Electrolytic polishing method of a semiconductor wafer. The method of claim 147, wherein Determining a profile of a metal layer on the wafer, and Directing an electrolyte fluid flow to the metal layer with a variable nozzle profile in accordance with a particular profile of the metal layer, Electrolytic polishing method of a semiconductor wafer. 152. The method of claim 152, The variable nozzle comprises two or more different nozzle profiles, Electrolytic polishing method of a semiconductor wafer. 152. The method of claim 152, The variable nozzle forms a variable polishing rate, Electrolytic polishing method of a semiconductor wafer. 152. The method of claim 152, The variable nozzle is selected to include a relatively large polishing rate in the thick portion of the metal layer and a relatively small polishing rate in the thin portion of the metal layer, Electrolytic polishing method of a semiconductor wafer. 152. The method of claim 152, The profile of the metal layer is determined by a termination detector located adjacent the two or more nozzles, Electrolytic polishing method of a semiconductor wafer. As an electropolishing nozzle of a semiconductor wafer, A channel having end openings and sidewalls for directing the electrolyte fluid, The channel comprises a conductor material, and the sidewalls are curved around the distal opening, Electrolytic polishing nozzles for semiconductor wafers. 158. The method of claim 157, Further comprising an insulator disposed outside of the sidewalls with respect to the channel, Electrolytic polishing nozzles for semiconductor wafers. 158. The method of claim 157, The channel comprises a cylinder, Electrolytic polishing nozzles for semiconductor wafers. 158. The method of claim 157, The channel comprises a conical cylinder, Electrolytic polishing nozzles for semiconductor wafers. 158. The method of claim 157, Further comprising a conductor structure disposed within the channel, Electrolytic polishing nozzles for semiconductor wafers. 161. The method of claim 161, Wherein the conductor structure comprises a rod, Electrolytic polishing nozzles for semiconductor wafers. 161. The method of claim 161, The conductor structure comprising a rod located within the channel, Electrolytic polishing nozzles for semiconductor wafers. 161. The method of claim 161, Wherein the conductor structure comprises a plurality of channels, Electrolytic polishing nozzles for semiconductor wafers. 175. The method of claim 164 wherein The cross-sectional size of the plurality of channels ranges from about 0.1 to 10 mm, Electrolytic polishing nozzles for semiconductor wafers. 175. The method of claim 164 wherein The cross-sectional size of the plurality of channels is about 1/10 of the diameter of the channels, Electrolytic polishing nozzles for semiconductor wafers. A method of deplating a nozzle used in an electropolishing apparatus, Providing an electrolyte fluid through the nozzle, and Applying an electric charge to the nozzle, The charge removes metal ions from the nozzle, Deflating method of the nozzle. 167. The method of claim 167, Applying a second opposite charge to the second nozzle, Wherein the electrolyte fluid forms a path between the first nozzle and the second nozzle, Deflating method of the nozzle. 168. The method of claim 168, Wherein the nozzle and the second nozzle are brought close to each other during the deplating process, Deflating method of the nozzle. 168. The method of claim 168, Wherein the nozzle is an anode and the second nozzle is a cathode Deflating method of the nozzle. 168. The method of claim 168, A portion of the deplated metal is dissolved in the electrolyte fluid Deflating method of the nozzle. 168. The method of claim 168, The concentration of metal ions in the electrolyte fluid is about 3% by weight or less, Deflating method of the nozzle. 168. The method of claim 168, Inverting said charge applied to said nozzle and said second nozzle for deplating said second nozzle, Deflating method of the nozzle. 168. The method of claim 168, Wherein the nozzle is an anode and the second nozzle is a cathode Deflating method of the nozzle. 167. The method of claim 167, The nozzle is charged with a DC power source, Deflating method of the nozzle. 167. The method of claim 167, The nozzle is charged to an AC power source, Deflating method of the nozzle. 167. The method of claim 167, Applying a second counter charge to the wafer, Deflating method of the nozzle. 178. The method of claim 177, A portion of the deplated metal is dissolved in the electrolyte fluid, Deflating method of the nozzle. 178. The method of claim 177, The concentration of metal ions in the electrolyte fluid is about 3% by weight or less, Deflating method of the nozzle. 178. The method of claim 177, The nozzle is charged with a DC power source, Deflating method of the nozzle. 178. The method of claim 177, The nozzle is charged to an AC power source, Deflating method of the nozzle. 167. The method of claim 167, Applying a second counter charge to the conductor material, Deflating method of the nozzle.