CN104584192A - Reflective deposition ring and substrate processing chamber including reflective deposition ring - Google Patents

Abstract

Apparatus for improving temperature uniformity across a substrate are provided herein. In some embodiments, a deposition ring for use in a substrate processing system to process a substrate may include an annular body having a first surface, an opposing second surface, and a central opening passing through the first and second surfaces, wherein the second surface is configured to be disposed over a substrate support having a support surface to support a substrate having a given width, and wherein the opening is sized to expose a predominant portion of the support surface; and wherein the first surface includes at least one reflective portion configured to reflect heat energy toward a central axis of the annular body, wherein the at least one reflective portion has a surface area that is about 5 to about 50 percent of a total surface area of the first surface.

Description

Reflective deposition ring and substrate processing chamber including reflective deposition ring

field

Embodiments of the invention generally relate to semiconductor processing equipment and techniques.

background

Semiconductor substrates are typically subjected to heat treatment following material processing, such as depositing materials on the substrate including features formed in its surface. Temperature uniformity across the semiconductor substrate is quite critical during thermal processing to efficiently deposit reflow material on the substrate during the deposition phase and to provide a more consistent distribution of material on the substrate and within the features. Certain reflow chambers use reflective surfaces to direct radiation towards the backside of the semiconductor substrate. However, space constraints within the reflow chamber substantially limit the area of the reflective surface, negatively impacting the temperature uniformity of the semiconductor substrate.

Accordingly, the inventors have provided apparatus for processing substrates that, in at least some embodiments, improves temperature uniformity across the substrate.

overview

Provided herein are apparatuses for improving temperature uniformity across a substrate. In some embodiments, a deposition ring for use in a substrate processing system to process a substrate may include an annular body having a first surface, an opposing second surface, and a central opening through the first surface and the second surface, wherein the second surface is configured to be disposed on a substrate holder having a support surface to support a substrate having a given width, and wherein the opening is sized to expose a substantial portion of the support surface; and wherein the first surface includes at least one reflective portion configured to reflect thermal energy toward the central axis of the annular body, wherein The at least one reflective portion has a surface area of about 5 percent to about 50 percent of the total surface area of the first surface.

In some embodiments, a deposition ring for use in a substrate processing system to process a substrate may include an annular body having a first surface, an opposing second surface, and a central opening through the first surface and the second surface, wherein the second surface is configured to be disposed on a substrate holder having a support surface to support a substrate having a given width, and wherein the opening is sized to expose a substantial portion of the support surface; and wherein the first surface includes at least one reflective portion configured to reflect thermal energy toward the central axis of the annular body, wherein The at least one reflective portion has a surface area that is at least five percent of the total surface area of the first surface.

In certain embodiments, a substrate processing chamber may include: a substrate support having a support surface to support a substrate having a given width; a radiant energy source located at a perimeter of the substrate processing chamber a region; a reflector disposed about the radiant energy source; and a deposition ring. The deposition ring may include an annular body having a first surface, an opposing second surface, and a central opening through the first surface and the second surface, wherein the second surface is configured to disposed on the substrate support, and wherein the size of the opening is designed to expose a major portion of the support surface; and at least one reflective portion, the at least one reflective portion is disposed on the first surface, and the at least one The reflective portion is configured to reflect thermal energy toward the central axis of the annular body, wherein the at least one reflective portion is about five percent to about fifty percent of the total surface area of the first surface.

Other embodiments and variations are discussed in more detail below.

Brief description of the drawings

Embodiments of the present invention, discussed in more detail below and briefly summarized above, can be understood by reference to the illustrative embodiments of the invention depicted in the accompanying drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of the invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

Figure 1 is a schematic cross-sectional view of a chamber according to some embodiments of the invention.

Figure 2 depicts a schematic view of a deposition ring according to some embodiments of the present invention.

Figure 2A depicts a cross-sectional side view of a deposition ring according to some embodiments of the invention.

3A-3C each depict a cross-sectional side view of a deposition ring according to some embodiments of the present invention.

4 is a top view of an example deposition ring according to some embodiments of the invention.

To facilitate understanding, like reference numerals have been used wherever possible to designate like elements that are common to the drawings. The figures are not drawn to scale and may be simplified for clarity. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

specific description

Embodiments of the present invention provide improved apparatus for processing substrates. In at least some embodiments, the apparatus can provide improved temperature uniformity across the substrate. For example, embodiments consistent with the present invention may be used in a dual function chamber where normal deposition of material on a substrate is followed by heating of that same substrate. Typically, the first surface of the substrate is highly reflective after material is deposited on the first surface of the substrate, and therefore, it would not be efficient to heat the substrate by shining a high intensity light source on the reflective first surface of the substrate. However, the second surface of the substrate (relative to the first surface, such as the bottom surface) may be more absorbing of light energy and may provide better thermal coupling. Additionally, because of space constraints, the heat source must be positioned such that the movement of the base is not hindered. Thus, the heat source can be located outside the perimeter of the substrate support base. In an embodiment consistent with the present invention, a combination of a reflective surface and a protective shield that reflects thermal energy from a surrounding heat source toward the substrate is provided.

Figure 1 depicts a schematic cross-sectional view of a chamber 100 according to some embodiments of the invention. The chamber 100 is configured for depositing material on a first side of a substrate and illuminating a second side of the substrate, the second side of the substrate being opposite to the first side of the substrate. Such a chamber 100 is a dual function chamber capable of performing both material processing and thermal processing on a substrate without removing the substrate from the chamber. In the example of a metal deposition process, the heat treatment may be a reflow process, eg, to reduce protrusion of metal in recesses of the substrate.

The chamber 100 has a wall portion 104 and a cover portion 102 , and the wall portion 104 and the cover portion 102 enclose an inner space 138 of the chamber 100 . The substrate holder 106 divides the inner space 138 into an upper space 136 and a lower space 134 . Process gases are allowed to enter the upper volume 136 of the chamber through the inlet 108 formed in the lid 102, and a substrate 168 disposed on the substrate receiving surface 116 of the substrate support 106 is exposed to processing at the processing position 160 of the chamber 100. gas.

In operation, the substrate support 106 moves vertically within the chamber 100, extending and retracting to various positions during different stages of processing. For example, the substrate support 106 may be actuated vertically to move a substrate 168 disposed on the substrate receiving surface 116 of the substrate support 106 between the processing position 160 and the transport position 124 of the chamber. The transfer location 124 defines a location at which substrate handling equipment (not shown) can handle the substrate 168 through the inlet 122 .

A plurality of lift pins 114 are disposed through a substrate receiving surface 116 of the substrate holder 106 . The plurality of lift pins 114 can be extended by the actuator 162 and moved independently of the substrate support 106 by a motor (not shown) coupled to the actuator 162 . For example, in certain embodiments, lift pins 114 may be actuated to lift and maintain substrate 168 near processing position 160 while substrate support 106 is retracted below radiation source plane 126 . In certain embodiments, by actuating the lift pins, the substrate 168 may be positioned at a thermal processing location 128 other than the processing location 160, which may be a material processing location.

The substrate receiving surface 116 may include an electrostatic chuck, which generally includes a conductor 158 disposed in the insulated substrate receiving surface 116 . The conductor 158 may be a sheet of material, a grid of wires, or a single path wire that is wound serpentinely through the substrate receiving surface 116 . Power is typically coupled to conductors 158 through conduits 156 disposed through the shaft 132 of the substrate support. When the substrate receiving surface 116 is bonded to the substrate 168 , the electrostatic chuck may be activated to secure the substrate 168 to the substrate support 106 . At this point, cooling gas may also be established through conduit 130 .

The substrate support 106 , on which the substrate is positioned, moves the substrate 168 toward the processing positions 128 and 160 . As the substrate support 106 is raised towards the processing position 160 , the substrate support 106 (with the deposition ring 118 placed on the protrusion 150 ) passes the radiation source assembly 112 . When the substrate receiving surface 116 reaches the processing location 160, the substrate 168 may be subjected to material processing, such as deposition, implantation, or etching. As described below, the deposition ring 118 may be configured to engage a cover ring 166 , which may be metal or ceramic, and the cover ring 166 extends outwardly from the deposition ring 118 toward the cover portion 102 . Engaged cover ring 166 improves the function of deposition ring 118 by controlling airflow from upper volume 136 through cover ring 166 into lower volume 134 . Deposition ring 118 engages cover ring 166 as substrate support 106 moves toward processing positions 160 and 128 . Cover ring 166 moves with deposition ring 118 and substrate support 106 as substrate support 106 moves from processing position 160 toward processing position 128 .

Radiation source assembly 112 is disposed at perimeter 142 of chamber 100 , and radiation source assembly 112 defines a radiation source plane 126 between processing location 160 and delivery location 124 . Radiation source assembly 112 generally surrounds substrate support 106 . Radiation source assembly 112 includes a housing 188 , a source of radiant energy 182 , at least one mount 184 protruding from housing 188 and supporting source of radiant energy 182 , and a reflective surface 186 of housing 188 . Housing 188 is typically made of a thermally conductive material, such as metal, eg stainless steel. Standoff 184 may be a thermally conductive material, such as metal, eg stainless steel, or a refractive material, such as ceramic. Radiant energy source 182 may be a lamp that produces radiation at wavelengths from infrared to violet, or radiant energy source 182 may be a microwave, millimeter wave, megahertz wave, submillimeter wave, or far infrared source. Radiant energy source 182 may generate radiation having a wavelength of from about 5x10-2 m to about 1x10-7 m. Example radiant energy sources include heat lamps, halogen lamps, arc lamps, and coaxial microwave or millimeter wave sources.

Reflective surface 186 of housing 188 is shaped to reflect radiation from radiant energy source 182 toward backside 172 of substrate 168 at processing location 128 or 160 (eg, as a reflector). In certain embodiments, the reflective surface 186 of the housing 188 is shaped to allow substantially uniform illumination of the substrate. Reflective surface 186 of housing 188 may have any desired shape, such as cylindrical, toroidal, elliptical, oval, or irregularly curved. In addition to or instead of being curved, the reflective surface 186 of the housing 188 may be a small flat surface. In some embodiments, the reflective surface 186 of the housing 188 can be a combination of multiple cylinders having the same or different radii of curvature, each cylinder can also be tapered or partially small plane. In certain embodiments, reflective surface 186 of housing 188 is semi-toroidal. In certain embodiments, the reflective surface 186 of the housing 188 includes a plurality of reflective members, each of which may independently be substantially flat, curved, tapered, or small planar, the reflective members is positioned close to the curved surface. Standoffs 184 are generally discontinuous, such as support pins, rods, or tabs, such that radiation from radiant energy source 182 reaches substantially the entire reflective surface 186 of housing 188 and is reflected toward backside 172 of substrate 168 .

The deposition ring 118 is disposed about an edge 148 of the substrate receiving surface 116 . Deposition ring 118 may be a metal or a metal-coated ceramic, such as stainless steel, alumina, or the like. Typically, the deposition ring 118 is formed of a material that can withstand high temperature processing. Additionally, as described below, the first surface 176 of the deposition ring 118 is reflective.

The deposition ring 118 substantially covers the outer extent 146 of the substrate support 106 to prevent deposition on the outer extent 146 . The deposition ring includes an annular body having a first surface 176 and an opposing second surface 178 . The second surface 178 rests, for example, on the protrusion 150 formed in the outer extension 146 of the substrate receiving surface 116 . In certain embodiments, the deposition ring has a diameter of about 12 inches to about 15 inches. The deposition ring also includes an opening 180 disposed through the center of the deposition ring 118 . The opening 180 disposed through the center of the deposition ring 118 is sized to expose a substantial portion of the substrate receiving surface 116 . In some embodiments, a substrate 168 disposed on the substrate receiving surface 116 is in contact with the deposition ring 118 . In an alternative embodiment, the substrate 168 may have an outer radius that is less than the inner radius of the deposition ring 118 such that the substrate 168 does not contact the deposition ring 118 .

After processing at processing location 160 is complete, substrate support 106 may be positioned for backside thermal processing of substrate 168 . By interrupting power to conductor 158 (or, in the vacuum chuck embodiment, interrupting the vacuum to the substrate receiving surface), any clamping force on substrate 168 can be released, substrate support 106 is then retracted, and lift pins 114 Actuated into the extended position. This releases the substrate 168 from the substrate receiving surface 116 and maintains the substrate 168 at the processing position 160 while the substrate support 106 is retracted to the thermal processing position below the radiation source plane 126 . The backside of the substrate is thus exposed to radiation from the radiation source assembly 112 . By actuating the lift pins, the substrate 168 may be moved to a heat treatment position 128 different from the treatment position 160, if desired. In such an embodiment, the processing location 160 may be a material processing location. Depending on the energy exposure requirements of a particular embodiment, the heat treatment location may be located above or below the material treatment location, as desired. The substrate 168 is shown in a heat treatment position in FIG. 1 .

During thermal processing, radiation source assembly 112 is powered on and energy is emitted from radiation source assembly 112 towards the backside of substrate 168 . The backside 172 of the substrate 168 is the surface of the substrate opposite the surface 170 on which material processing is performed. In addition to providing an integrated material and thermal processing chamber, illuminating the backside 172 of the substrate 168 in this manner may improve the energy efficiency of thermal processing by illuminating the less reflective surface of the substrate 168 . In some embodiments, the material treatment performed on the substrate 168 forms a reflective layer or partial layer on the surface 170 that reduces energy absorption. Illumination of the backside 172 then avoids increased reflectivity. Additionally, the reflectivity of surface 170 may reflect radiation from radiation source assembly 112 traveling through substrate 168 and back through substrate 168 to further improve efficiency.

As described above, deposition ring 118 includes first surface 176 configured to increase the amount of radiation reflected from radiant energy source 182 toward the substrate at processing location 160 (e.g., at least portions of the first surface are configured to to reflect radiation radially inward toward the central axis 174 of the chamber). In certain embodiments, deposition ring 118 may be configured as an extension of reflective surface 186 of radiation source assembly 112 .

In certain embodiments, the first surface 176 is textured to promote adhesion of deposited material on the first surface 176, thereby reducing the buildup of deposited material on the first surface 176 of the deposition ring 118 during substrate processing. Any spalling of material. In certain embodiments, the first surface 176 has a roughness of about 80 to about 100 microinches RMS.

Figure 2 illustrates a cross-sectional side view of an example deposition ring 118, according to some embodiments of the invention. FIG. 2A depicts a detailed cross-sectional side view of the deposition ring 118 of FIG. 2 . 3A-3C illustrate various non-limiting example embodiments of the first surface 176 of the deposition ring.

In some embodiments, as shown in FIGS. 2-2A and 3A-3C, the first surface 176 of the deposition ring 118 includes at least one reflective portion 204 configured to divert light energy The reflection is towards the central axis of the deposition ring (eg, the deposition ring is also a reflector). For example, as shown in FIGS. 2A and 3A-3B , the first surface 176 of the deposition ring 118 may include a reflective portion 204 . The first surface 176 of the deposition ring 118 may also include more than one reflective portion 204, as shown in FIG. 3C. Although the entire first surface 176 of the deposition ring 118 may be reflective, when used herein in relation to the deposition ring, the terms "reflective surface" or "reflective portion of the surface" are used to describe configurations that reflect light energy toward the deposition ring. This surface of the central axis of the ring.

In some embodiments, reflective portion 204 includes a substantial portion of first surface 176 . In certain embodiments, the reflective portion 204 is about five percent to about fifty percent of the first surface 176 . The reflective portion 204 is configured to reflect thermal energy towards the central axis 174 of the annular body. In some embodiments, the included angle of the reflective portion relative to the central axis of the annular body is an angle of about 0 degrees to about 30 degrees, or up to about 30 degrees. The first surface 176 comprising at least one reflective portion 204 and configured to reflect thermal energy towards the central axis 174 of the annular body advantageously increases the amount of radiation directed towards the backside 172 of the substrate, thereby improving (eg, reducing) the substrate. temperature non-uniformity. Additionally, the inventors have discovered that at least one reflective portion 204 may advantageously be incorporated into the deposition annulus along a portion of first surface 176 (e.g., having a surface area of about five to five percent of the total surface area of first surface 176). approximately 50 percent) to advantageously improve (eg, reduce) the temperature non-uniformity of the substrate while maintaining the functionality of the deposition ring. The increase in the amount of radiation directed towards the substrate backside 172 is advantageously performed within the spatial constraints of the reflow chamber.

In certain embodiments, the reflective portion 204 of the deposition ring 118 is coated with a reflective material prior to placing the deposition ring 118 into the chamber. In some embodiments, deposition ring 118 is coated with a reflective material within chamber 100 . The reflective portion 204 may be coated with a reflective material such as copper, gold, aluminum, or the like.

The reflective portion 204 of the deposition ring 118 is curved and/or faceted in a manner that is compatible with the curvature and/or faceting of the reflective surface 186 of the housing 188 such that the reflective surface 186 of the housing 188 and the reflective surface of the deposition ring 118 Portions 204 together form a composite reflector configured to direct as much radiation from radiant energy source 182 as uniformly as possible to the backside of the substrate overlying radiant energy source 182 .

In certain embodiments, the first surface 176 includes a sloped surface 210 . In FIG. 2A and FIGS. 3A-3B , the reflective portion 204 is disposed near the inclined surface 210 . The sloped surfaces advantageously function to facilitate containment of deposited material and/or to guide the substrate 168 into position as the substrate 168 is lowered into the central opening of the deposition ring 118 . In some embodiments, the sloped surface 210 may also be a reflective portion (eg, a second reflective portion), similar to the reflective portion 204 .

In certain embodiments, as depicted in FIGS. 2A and 3A-3B , the first surface 176 includes a flat portion 206 disposed near the outer periphery of the deposition ring 118 to engage the cover ring 166 , The cover ring 166 may be metal or ceramic, and the cover ring 166 extends outwardly from the deposition ring 118 toward the cover portion 102 . The cover ring 166 and flat portion 206 can improve the function of the deposition ring 118 by controlling the airflow from the upper space 136 through the cover ring 166 and into the lower space 134 . Deposition ring 118 engages cover ring 166 as substrate support 106 moves toward processing positions 160 and 128 . Cover ring 166 moves with deposition ring 118 and substrate support 106 as substrate support 106 moves from processing position 160 toward processing position 128 .

In some embodiments, as shown in FIGS. 2A and 3A-3B , the first surface 176 includes a groove 208 . In some embodiments, the groove 208 may be disposed radially inward of the flat portion 206 . Grooves 208 advantageously provide a growing reservoir for deposited material during substrate processing. In some embodiments, the sloped surface 210 may be disposed near or beside the groove 208 . For example, in some embodiments, the sloped surface 210 may form one wall of the groove 208 .

FIG. 4 is a top view of an example deposition ring 118 according to some embodiments of the invention. The deposition ring 118 includes an outer diameter 402 , an inner diameter 404 , and a central opening 406 . In certain embodiments, the deposition ring 118 may include one or more protrusions 408 that may assist in positioning the deposition ring 118 .

Referring back to FIG. 1 , the substrate is typically reengaged to the substrate receiving surface 116 by retracting the lift pins 114 after thermal processing is complete. The clamping force can be reapplied and the cooling gas re-established to cool the substrate. The substrate holder 106 may then be moved into position for further processing, or returned to the transport position for retrieval of the substrate, if desired. Substrate access is provided by extending the lift pins 114 when the substrate support 106 is in the delivery position, so a mechanical blade can be inserted between the substrate and the substrate receiving surface 116 .

The substrate need not be positioned at the same location for material (ie, deposition or implantation) and heat treatment. In the foregoing, it was suggested that the treatment location 160 be the same during material and heat treatment, but this need not be the case. For example, a heat treatment location may be different than a material treatment location. The substrate can be raised or lowered from the material processing position to the heat processing position. The location of the heat treatment location relative to the material treatment location generally depends on the design of the radiation source and the requirements of the material treatment.

Accordingly, improved apparatus for improving temperature uniformity across a substrate has been disclosed herein. The inventive apparatus advantageously facilitates a reflow phase to enable material deposited on the sidewalls of a feature to move to the bottom of the feature, thereby reducing the aspect ratio of the structure.

While the foregoing relates to embodiments of the invention, other and further embodiments of the invention may be envisioned without departing from the essential scope thereof.

Claims (15)

1. A deposition ring for use in a substrate processing system to process a substrate, the deposition ring comprising: an annular body, the annular body has a first surface, an opposite second surface, and a central opening through which the first surface and the second surface pass, wherein the second surface is configured to be disposed on the substrate above a support, the substrate support having a support surface to support a substrate of a given width, and wherein the opening is sized to expose a substantial portion of the support surface; and wherein the first surface includes at least one reflective portion configured to reflect thermal energy toward the central axis of the annular body, wherein the at least one reflective portion has a surface area equal to that of the first surface at least about five percent of the total surface area. 2. The deposition ring of claim 1, wherein the at least one reflective portion has a surface area that is at least about five percent to about fifty percent of the total surface area of the first surface. 3. The deposition ring of claim 1, wherein the at least one reflective portion is coated with a reflective material. 4. The deposition ring of claim 1, wherein the ring body further comprises: A groove is disposed in the first surface and is configured to receive growth of deposited material during substrate processing. 5. The deposition ring of claim 1, wherein the ring body further comprises: A flat portion disposed near the outer periphery of the deposition ring to support the cover ring. 6. The deposition ring of claim 1, wherein the ring body further comprises: an inclined surface disposed on the first surface near the inner periphery of the deposition ring, wherein the inclined surface is configured to position the substrate in the center when the substrate is present above the opening. 7. The deposition ring of any one of claims 1-6, wherein the first surface has a roughness of about 80 microinches to about 100 microinches RMS. 8. The deposition ring of any one of claims 1-6, wherein the deposition ring has a diameter of about 12 inches to about 15 inches. 9. The deposition ring of any one of claims 1-6, wherein the inclination of the at least one reflective portion is from about 0 degrees to about 30 degrees. 10. The deposition ring of any one of claims 1-6, wherein the annular body includes a plurality of reflective portions, each reflective portion of the plurality of reflective portions having an angle such that in the presence of the substrate , reflecting thermal energy toward the substrate. 11. The deposition ring of any one of claims 1-6, wherein the annular body further comprises a first step connecting the second surface to the annular body the inner diameter of . 12. The deposition ring of any one of claims 1-6, wherein the at least one reflective portion is a major portion of the first surface. 13. The deposition ring of any one of claims 1-3, further comprising: a groove disposed in the first surface and configured to receive growth of deposited material during substrate processing; a flat portion disposed near the outer periphery of the deposition ring to support the cover ring; and an inclined surface disposed on the first surface radially outward of and adjacent to the groove, wherein the inclined surface is configured to, in the presence of the substrate, The base plate is positioned over the central opening. 14. A substrate processing chamber comprising: a substrate holder having a support surface to support a substrate having a given width; a radiant energy source located at a peripheral region of the substrate processing chamber; a reflector disposed about the radiant energy source; and A deposition ring arranged around the support surface of the substrate support, the deposition ring being a deposition ring as claimed in any one of the preceding claims. 15. The substrate processing chamber of claim 14, wherein the first surface of the deposition ring is an extension of the reflector.