Susceptor Improvement

Abstract

A susceptor for processing a substrate is provided, comprising a base and a coating formed over the base. The base includes an outer rim having an inner edge, an outer edge, and a top connecting the inner edge to the outer edge, and an inner dish disposed within the outer rim and coupled to the outer rim, the inner dish being recessed from the top of the outer rim and having a front surface and an opposite back surface. The coating has an outer surface including a first portion formed over the front surface of the inner dish. The first portion of the outer surface of the coating includes a first region and a second region, the first region having a first average level of roughness and the second region having a second average level of roughness.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate generally to susceptors for use in processing substrates (e.g., semiconductor substrates), and more particularly to susceptors having features for improving thermal uniformity across the substrate during processing. [Background technology]

[0002] Susceptors are often used in epitaxy processes to support the substrate and to heat the substrate to a very uniform temperature. Susceptors often have a platter- or dish-shaped upper surface that is used to support the substrate from below around its edge(s) while leaving a small gap between the remaining lower surface of the substrate and the upper surface of the susceptor. Precise control over a heating source, such as multiple heat lamps disposed below the susceptor, allows the susceptor to be heated within very tight tolerances. The heated susceptor can then transfer heat to the substrate primarily through radiation emitted by the susceptor.

[0003] Despite precise control of susceptor heating in epitaxy, temperature non-uniformities persist across the upper surface of the substrate, often reducing the quality of the process (e.g., deposition) being performed on the substrate. Thus, there is a need for improved susceptors for supporting and heating substrates during processes such as semiconductor processing. Summary of the Invention

[0004] Embodiments of the present disclosure relate generally to susceptors for use in processing substrates (e.g., semiconductor substrates), and more particularly to susceptors in which regions of one or more surfaces of the susceptor have different levels of roughness to improve thermal uniformity across the substrate during processing.

[0005] In one embodiment, a susceptor for processing a substrate is provided, comprising: a base; and a coating formed over the base. The base includes an outer rim having an inner edge, an outer edge, and a top connecting the inner edge to the outer edge; and an inner dish disposed within the outer rim and coupled to the outer rim, the inner dish recessed from the top of the outer rim, the inner dish having a front surface and an opposite back surface. The coating has an outer surface including a first portion formed over the front surface of the inner dish, the first portion of the outer surface of the coating including a first region and a second region, the first region having a first average level of roughness and the second region having a second average level of roughness, the first average level of roughness being at least 50% greater than or 33% less than the second average level of roughness.

[0006] In another embodiment, a susceptor for processing a substrate is provided, including a base and a coating formed over the base. The base includes an outer rim having an inner edge, an outer edge, and a top connecting the inner edge to the outer edge, and an inner dish disposed within the outer rim and coupled to the outer rim, the inner dish being recessed from the top of the outer rim, the inner dish having a front side and an opposite back side. The coating has an outer surface including a first portion formed over the back side of the inner dish, the first portion of the outer surface of the coating including a first region and a second region, the first region having a first average level of roughness and the second region having a second average level of roughness, the first average level of roughness being at least 50% greater than or 33% less than the second average level of roughness.

[0007] In another embodiment, a susceptor for processing a substrate is provided, the susceptor including a base having an outer rim having an inner edge, an outer edge, and a top connecting the inner edge to the outer edge, and an inner dish disposed within the outer rim and coupled to the outer rim, the inner dish being recessed from the top of the outer rim, the inner dish having a front surface and an opposite back surface. The outer surface of the base includes a first portion on the front surface of the base or the back surface of the base, the first portion including a first region and a second region, the first region having a first average level of roughness and the second region having a second average level of roughness, the first average level of roughness being at least 50% greater than or 33% less than the second average level of roughness.

[0008] So that the above-recited features of the present disclosure may be understood in detail, a more particular description of the present disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only exemplary embodiments and therefore should not be considered limiting of its scope, as other equally effective embodiments may be recognized. [Brief explanation of the drawings]

[0009] [Figure 1] 1 illustrates a cross-sectional view of a processing chamber, according to one embodiment. [Figure 2A] 2 is a cross-sectional side view of the susceptor from FIG. 1 according to one embodiment. [Figure 2B] 2 is a cross-sectional side view of the susceptor from FIG. 1 with a substrate on the susceptor, according to one embodiment. [Figure 2C] 2 is a plan view of a first portion of an outer surface of a coating on a susceptor from FIG. 1 according to one embodiment. [Figure 3] FIG. 10 is a cross-sectional side view of a susceptor according to another embodiment. [Figure 4] FIG. 10 is a cross-sectional side view of a susceptor according to another embodiment. [Figure 5] FIG. 10 is a cross-sectional side view of a susceptor according to another embodiment. [Figure 6] FIG. 2 is a plan view of a first portion of a susceptor according to another embodiment.

[0010] For ease of understanding, where possible, like reference numerals have been used to designate like elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiments of the present disclosure generally relate to susceptors for use in processing substrates (e.g., semiconductor substrates), and more particularly, to susceptors in which regions of one or more surfaces of the susceptor have different levels of roughness to improve thermal uniformity across the substrate during processing. The susceptor surfaces with varying levels of roughness can be interior or exterior surfaces. The level of roughness of a region of a surface can affect the heat transferred from that region of the surface to the substrate. Thus, varying the level of roughness across different regions of one or more surfaces of the susceptor can be used to address temperature non-uniformities across different regions of the substrate during processing, which can improve the uniformity of a process being performed on the substrate, such as improving thickness uniformity for deposition.

[0012] FIG. 1 is a cross-sectional view of a processing chamber 100, according to one embodiment. The processing chamber 100 may be configured to perform an epitaxial (Epi) deposition process. A susceptor 200 is disposed in the processing chamber 100. A substrate 50 is disposed on the susceptor 200. A simplified diagram of the susceptor 200 is shown in FIG. 1. Additional details regarding the susceptor 200 are shown in FIGS. 2A-2C. The processing chamber 100 is configured to allow exchange of the substrate 50 through an opening 160, which may be opened by a slit valve 165 of the processing chamber 100.

[0013] The processing chamber 100 includes a housing structure 102 made from a process-resistant material, such as aluminum or stainless steel, e.g., 316L stainless steel. The housing structure 102 encloses various functional elements of the processing chamber 100, such as a quartz chamber 104, which includes an upper quartz chamber 106 and a lower quartz chamber 108. The quartz chamber 104 encloses a processing volume 110 (also referred to as an interior volume). One or more liners 136, 137 can insulate the quartz chamber 104 from the housing structure 102.

[0014] The processing chamber 100 includes a substrate support assembly 116. The substrate support assembly 116 may include a support 117 and a shaft 118. A susceptor 200 may be disposed on the support 117. The substrate support assembly 116 may further include an actuator 119 for rotating the shaft 118 and the susceptor 200. Rotation of the susceptor 200 during processing generally improves process uniformity; unfortunately, non-uniformities, such as temperature non-uniformities, remain on the substrate 50 during processing. The susceptor 200, as well as other susceptors described in this disclosure, include features, such as surfaces with different average levels of roughness, to address these non-uniformities.

[0015] In some embodiments, the actuator 119 can also raise and lower the support 117, which can be useful when transferring the substrate 50 or for use in different processing positions. In some embodiments, the substrate support assembly 116 can include lift pins (not shown) that can be raised and lowered to facilitate swapping of the substrate 50. The susceptor 200 can include lift pin holes through which the lift pins can extend.

[0016] Reactive species may be provided to the processing volume 110 by a gas distribution assembly (not shown), and processing by-products may be removed from the processing volume 110 by an outlet port (not shown), which is typically in communication with a vacuum source (not shown). In some embodiments, gas is provided to the outer portion of the processing volume 110, for example, through one or more openings in the liners 136, 137. In these embodiments, the gas may flow from the outer portion to a region spanning the susceptor 200 and the substrate 50 and then exit through the outlet port.

[0017] A purge gas (not shown) may also be provided below the susceptor 200 to prevent reactive species from entering the region in the processing volume 110 below the susceptor 200. A preheat ring 170 may be disposed around the susceptor 200. The preheat ring 170 may be used to preheat reactive species as gas travels, for example, across the susceptor 200 from an outer portion of the processing volume 110 to an inner portion of the processing volume. The preheat ring 170 may also be used to control the flow of purge gas around the susceptor 200.

[0018] Heating of the substrate 50 and / or the process volume 110 may be provided by radiation sources such as an upper lamp module 124A and a lower lamp module 124B. In one embodiment, the upper lamp module 124A and the lower lamp module 124B are infrared (IR) lamps.

[0019] Figure 2A is a cross-sectional side view of the susceptor 200 from Figure 1, according to one embodiment. Figure 2B is a cross-sectional side view of the susceptor 200 with a substrate 50 on the susceptor 200, according to one embodiment.

[0020] The susceptor 200 includes a base 201 and a coating 240 formed over the base 201. The coating 240 includes an outer surface 241. In embodiments, the outer surface of the base, including the coating formed over the base, may be referred to as the inner surface. In some embodiments, the coating 240 may be omitted, as described in further detail below. The base 201 may be formed from a ceramic material (e.g., aluminum oxide) or a graphite material. The coating 240 may be a silicon material, such as silicon carbide, or other process-resistant material. In some embodiments, the coating 240 may have a substantially uniform thickness over the entire base 201.

[0021] The base 201 includes an outer rim 210 and an inner dish 202 coupled to the outer rim 210. The outer rim 210 includes an inner edge 211, an outer edge 212, and a top 213 connecting the inner edge 211 to the outer edge 212. The outer rim 210 further includes a bottom 214 connected to the outer edge 212.

[0022] The inner dish 202 includes an outer portion 204 disposed around a central portion 203. The central portion 203 may be flat (i.e., horizontal in FIGS. 2A and 2B ). The outer portion 204 may be sloped. The outer portion 204 extends from the central portion 203 to the inner edge 211 of the outer rim 210. The inner dish 202 is recessed from the top 213 of the outer rim 210. The central portion 203 of the inner dish 202 is also recessed from the inner edge 211 of the outer rim 210. Although the outer portion 204 is shown as having a linear slope, in some embodiments, the outer portion 204 may be curved. Furthermore, although the central portion 203 is shown as flat, in some embodiments, the central portion 203 may be curved (e.g., concave). Furthermore, in some embodiments, the outer portion 204 may be omitted. In some of these embodiments, another feature, such as an annular ridge for supporting the substrate, may be used to create a gap between the bottom of the substrate 50 and the top of the central portion 203 of the inner dish 202.

[0023] The inner dish 202 further includes a front surface 208 and an opposite back surface 209. The front surface 208 faces the substrate 50 when the substrate 50 is placed on the susceptor 200. As shown in FIG. 2B , the substrate 50 is spaced from a portion of the outer surface 241 of the coating 240 located on the central portion 203 of the inner dish 202. The gap between the bottom of the substrate and the front surface 208 of the inner dish 202 allows more of the heating of the substrate to be radiative, which can improve temperature uniformity of the substrate relative to conductive heating between contacting surfaces.

[0024] 2C is a plan view of a first portion 2411 of an outer surface 241 of a coating 240 on a susceptor 200, according to one embodiment. FIG. 2C will be described with additional reference to FIGS. 2A and 2B. The first portion 2411 of the outer surface 241 shown in FIG. 2C is on the central portion 203 and the outer portion 204 of the inner dish 202. The first portion 2411 of the outer surface 241 of the coating 240 includes a first set of regions 250 and a second set of regions 260 having substantially different average levels of roughness Ra to improve temperature uniformity of the substrate 50 during processing.

[0025] As used herein, the Ra value (also referred to as the average level of roughness) for a surface refers to the average of the profile height deviations from the mean line for the surface. The Ra value can have units of length (e.g., micrometers (μm) or millimeters (mm)). Also, as used herein, substantially different average levels of roughness for two or more regions refers to regions in which one of the two or more regions has an average level of roughness Ra that is at least 50% greater or 33% less than the average level of roughness Ra of at least one of the one or more other regions. In some embodiments, the average level of roughness between the two regions can be smaller (e.g., one region has an average level of roughness that is 10% greater than the average level of roughness for the other region) or greater (e.g., one region has an average level of roughness that is twice as great as the average level of roughness for the other region).

[0026] As used herein, the average level of roughness of two regions is considered to be substantially the same if the average level of roughness for the first region is within plus or minus 5% of the average level of roughness for the second region. Although this disclosure has generally described different levels of roughness as different levels of average roughness Ra, other roughness parameters may be used, such as the root mean square average or quadratic average of the profile height deviation from the mean line for the surface, and the benefits of this disclosure may be obtained by using these other roughness parameters.

[0027] The first set of regions 250 includes a first region 251, a second region 252, and a third region 253. The second set of regions 260 includes a first region 261, a second region 262, and a third region 263.

[0028] Regions 261-263 are shown as rectangles in Figures 2A-2B to indicate the location of these regions on outer surface 241 in the cross-sectional views of Figures 2A-2B. The use of these rectangles does not convey information regarding the depth of regions 261-263 in the Z direction. The descriptions in this paragraph regarding the use of rectangles and their depths also apply to the use of similarly sized rectangles 361-363, 461-463, and 561-563 in Figures 3-5.

[0029] 2A and 2C, the first region 251 may be a central region. The first region 251 may have a circular shape in plan view. The second region 252 and the third region 253 may have ring shapes in plan view. Similarly, the first region 261, the second region 262, and the third region 263 may have ring shapes in plan view. The first region 261 is located between the first region 251 and the second region 252. The second region 252 is located between the first region 261 and the second region 262. The second region 262 is located between the second region 252 and the third region 253. The third region 253 is located between the second region 262 and the third region 263. The third region 263 is located between the third region 253 and the inner edge 211 of the outer rim 210. The outer boundary of third region 263 in FIG. 2C is the location where third region 263 meets inner edge 211 of outer rim 210.

[0030] The first set of regions 250 are each individually separated from one another by a region of the second set of regions 260. Similarly, the second set of regions 260 are each individually separated from one another by a region of the first set of regions 250. Although there are three regions 250 and three regions 260, in other embodiments there may be more or fewer of each of the regions 250, 260. In one embodiment, there are only three regions total, such as an embodiment including only the first region 251, the second region 252, and the first region 261, with the first region 261 being disposed between the first region 251 and the second region 252. Another embodiment may include only two regions of varying roughness, for example, when the regions of varying roughness are used to address temperature non-uniformities that exist only at the center or edge of the substrate.

[0031] Each of the individual regions 251-253, 261-263 can cover a significant portion of the first portion 2411 of the outer surface 241 of the coating 240. For example, in some embodiments, each individual region 251-253 can cover at least 2.5%, at least 5%, at least 10%, at least 15%, or at least 25% of the area surrounded by the outer rim 210 and corresponding to the front surface 208 of the inner dish 202.

[0032] In some embodiments, the first set of regions 250 can have an average level of roughness that is at least 50% greater, at least 2 times greater, at least 5 times greater, or at least 10 times greater than the average level of roughness of the second set of regions 260. Conversely, in other embodiments, the second set of regions 260 can have an average level of roughness that is at least 50% greater, at least 2 times greater, at least 5 times greater, or at least 10 times greater than the average level of roughness of the first set of regions 250.

[0033] The determination of whether the first set of regions 250 should be formed to have a rougher surface than the second set of regions 260 may be based on (1) where temperature non-uniformities on the substrate 50 are located during a process performed on an otherwise similar susceptor without the roughness modification, and (2) the temperature difference between the susceptor 200 and the substrate 50 while the process is being performed. A surface with a higher level of roughness may have more surface area per unit area across a two-dimensional plane (e.g., the XY plane in FIG. 2C ) than an otherwise similar surface with a lower level of roughness. Thus, a region of the outer surface 241 of the susceptor 200 with a higher average level of roughness and a larger surface area has a higher view factor and can radiate more heat to or absorb more heat from the substrate 50, depending on the temperature difference between the susceptor 200 and the substrate 50 during a given process, compared to a similar-sized region of the outer surface 241 with a lower average level of roughness. As a result, the average level of roughness of the outer surface 241 of the coating 240 of the susceptor 200 can be adjusted across different regions of the outer surface 241 (e.g., regions 250, 260) to offset temperature non-uniformities across the substrate that exist when the substrate is processed on an otherwise similar susceptor having an outer surface with an unaltered level of roughness (e.g., a relatively constant level).

[0034] Because susceptors (e.g., susceptor 200) are often rotated during processing, temperature non-uniformities in the substrate during processing as well as non-uniformities in the process results (e.g., thickness deposition non-uniformities) often exist in a ring-like pattern across the surface of substrate 50. Thus, using susceptor 200 having a coating 240 with an outer surface 241 that includes regions 250, 260 with substantially different average levels of roughness and that has a ring shape all except for a central region 251 is one example of a solution for addressing temperature non-uniformities on the substrate that exist in a ring-like pattern. For processes in which the susceptor is not rotated, patterns for varying roughness across the susceptor (e.g., see FIG. 6 ) other than a ring-shaped pattern may be more useful for addressing non-uniformities across the substrate, such as temperature non-uniformities.

[0035] In some embodiments, the difference in average level of roughness between regions 250 and 260 can be obtained by (1) roughening one set of regions 250, 260 without modifying the other, (2) smoothing one set of regions 250, 260 without modifying the other, or (3) modifying each of regions 250, 260 with roughening or smoothing. In some embodiments, smoothing can be performed by polishing. Polishing a region of a surface reduces the roughness of that region relative to an unpolished region. Roughening a region increases the roughness of that region relative to an unroughened region. Roughening can be performed by creating grooves, scratches, divot-like patterns, or other surface features using machining, blasting, mechanical treatment, and other techniques. In some embodiments, laser energy can also be used to modify the roughness of a surface.

[0036] Although susceptor 200 is described as having a first set of regions 250 having a first average level of roughness and a second set of regions 260 having a second average level of roughness, there is no requirement that it have only two levels of roughness. For example, some embodiments of a susceptor can include three or more regions of a given surface, each having a different average level of roughness. In one embodiment of susceptor 200, six different regions 251-253, 261-263, individually, each have a substantially different average level of roughness than each of the other five regions. Each susceptor described in this disclosure (see, e.g., Figures 2A-6) can have a surface (e.g., the surface of coating 240 or base 201) that can include three or more regions, each of which has an average level of roughness that is substantially different from the average level of roughness of two or more other regions on that surface. Additionally, although the susceptors disclosed herein are merely described as having a base and a single coating, other susceptors may include three or more components (e.g., layers), each having a surface whose roughness can be modified to improve temperature uniformity of a process to be performed on the susceptor.

[0037] 3 is a cross-sectional side view of a susceptor 300 according to another embodiment. The susceptor 300 is the same as the susceptor 200 described above, except that different portions of the outer surface 241 of the coating 240 include regions with different average levels of roughness. On the susceptor 300, instead of the first portion 2411 of the outer surface 241 above the inner dish 202 on the susceptor 200, a lower portion 2412 of the outer surface 241 of the coating 240 below the inner dish 202 includes a region with a different average level of roughness.

[0038] The lower portion 2412 (first portion) of the outer surface 241 includes a first set of regions 350 and a second set of regions 360. The first set of regions 350 includes a first region 351, a second region 352, and a third region 353. The second set of regions 360 includes a first region 361, a second region 362, and a third region 363. The roughness level of the first set of regions 350 is substantially different from the roughness level of the second set of regions 360. For example, the average level of roughness Ra of the first set of regions 350 can be at least 50% greater than the average level of roughness Ra of the second set of regions 360.

[0039] Although not shown, a bottom view of the lower portion 2412 of the susceptor 300 may appear the same as the plan view of the first portion 2411 of the susceptor 200 shown in FIG. 2C . For example, the first region 351 may have a circular shape in the XY plane. The second region 352 and the third region 353 may have ring shapes in the XY plane. Similarly, the first region 361, the second region 362, and the third region 363 may each have a ring shape in the XY plane. The first region 361 is located between the first region 351 and the second region 352. The second region 352 is located between the first region 361 and the second region 362. The second region 362 is located between the second region 352 and the third region 353. The third region 353 is located between the second region 362 and the third region 363. The third region 363 is located between the third region 353 and the bottom 214 of the outer rim 210.

[0040] The roughness of regions 350, 360 can be varied for the same reasons as described above for regions 250, 260 on susceptor 200. For example, roughening a region can increase the surface area of ​​that region across its two-dimensional area (e.g., across its area in the XY plane in FIG. 3). The increased surface area increases radiative heat transfer for that region relative to an unroughened region of the same size. On the other hand, smoothing (e.g., polishing) a region can reduce the surface area of ​​that region across its two-dimensional area (e.g., across its area in the XY plane in FIG. 3), which can decrease radiative heat transfer and effective emissivity for that region relative to an unroughened region of the same size.

[0041] In some embodiments, the bottom of the susceptor is often a flat surface, but the top surface of the susceptor underlying the substrate being processed often has some slope or curve that can make some roughening or polishing techniques more difficult, so altering the roughness of the bottom surface of the susceptor 300 shown in Figure 3 may be easier than altering the roughness of the top surface of the susceptor 200 shown in Figure 2A. Additionally, the fact that the inner dish 202 is recessed inside the outer rim 210 may also make altering the roughness of the top surface of the susceptor more difficult than altering the roughness of the bottom surface of the susceptor.

[0042] 4 is a side cross-sectional view of a susceptor 400 according to another embodiment. The susceptor 400 is the same as the susceptor 200 described above (see FIGS. 2A-2C ), except that instead of the outer surface 241 of the coating 240 including different levels of roughness, the front surface 208 of the inner dish 202 of the base 201 includes regions with different levels of roughness. The front surface 208 of the inner dish 202 is the surface of the base 201 that faces the substrate being processed. The roughness of the front surface 208 of the inner dish 202 can be altered (e.g., roughened or smoothed) before the coating 240 is formed over the base 201.

[0043] The front surface 208 of the inner dish 202 includes a first set of regions 450 and a second set of regions 460. The first set of regions 450 includes a first region 451, a second region 452, and a third region 453. The second set of regions 460 includes a first region 461, a second region 462, and a third region 463. The average level of roughness of the first set of regions 450 is substantially different from the average level of roughness of the second set of regions 460, such as the average level of roughness Ra of the first set of regions 450 being at least 50% greater than the average level of roughness Ra of the second set of regions 460.

[0044] The front surface 208 of the inner dish 202 has the same size in the XY plane as the first portion 2411 of the outer surface 241 of the coating 240 shown in the XY plane in FIG. 2C. Although not shown, a plan view of the front surface 208 of the inner dish 202 of the susceptor 400 may appear the same as the plan view of the first portion 2411 of the susceptor 200 shown in FIG. 2C. For example, the first region 451 may have a circular shape in the XY plane. The second region 452 and the third region 453 may have ring shapes in the XY plane. Similarly, the first region 461, the second region 462, and the third region 463 may each have a ring shape in the XY plane. The first region 461 is located between the first region 451 and the second region 452. The second region 452 is located between the first region 461 and the second region 462. The second region 462 is located between the second region 452 and the third region 453. The third region 453 is located between the second region 462 and the third region 463. The third region 463 is located between the third region 453 and the inner edge 211 of the outer rim 210.

[0045] The roughness of one or more of the regions 450, 460 may be altered (e.g., smoothed or roughened) for the same reasons described above for altering the roughness of one or more of the regions 250, 260 on the susceptor 200. For example, roughening a region can increase the surface area of ​​that region over its two-dimensional area (e.g., over its area in the XY plane in FIG. 4). The increased surface area increases heat transfer for that region relative to an unroughened region of the same size. Similarly, smoothing a region can reduce the surface area and heat transfer for the region as described above.

[0046] 5 is a side cross-sectional view of a susceptor 500 according to another embodiment. The susceptor 500 is the same as the susceptor 200 described above (see FIGS. 2A-2C), except that instead of the first portion 2411 of the outer surface 241 of the coating 240 including different levels of roughness, the back surface 209 of the inner dish 202 includes an area with different levels of roughness. The roughness of the back surface 209 of the inner dish 202 can be altered (e.g., roughened or smoothed) before the coating 240 is formed over the base 201.

[0047] The back surface 209 of the inner dish 202 includes a first set of regions 550 and a second set of regions 560. The first set of regions 550 includes a first region 551, a second region 552, and a third region 553. The second set of regions 560 includes a first region 561, a second region 562, and a third region 563. The roughness level of the first set of regions 550 is substantially different from the average level of roughness of the second set of regions 560, such as the average level of roughness Ra of the first set of regions 550 being at least 50% greater than the average level of roughness Ra of the second set of regions 560.

[0048] The back surface 209 of the inner dish 202 has the same size in the XY plane as the first portion 2411 of the outer surface 241 of the coating 240 shown in the XY plane in FIG. 2C. Although not shown, a bottom view of the back surface 209 of the inner dish 202 of the susceptor 500 may appear the same as the top view of the first portion 2411 of the susceptor 200 shown in FIG. 2C. For example, the first region 551 may have a circular shape in the XY plane. The second region 552 and the third region 553 may have ring shapes in the XY plane. Similarly, the first region 561, the second region 562, and the third region 563 may each have a ring shape in the XY plane. The first region 561 is located between the first region 551 and the second region 552. The second region 552 is located between the first region 561 and the second region 562. The second region 562 is located between the second region 552 and the third region 553. The third region 553 is located between the second region 562 and the third region 563. The third region 563 is located between the third region 553 and the bottom 214 of the outer rim 210.

[0049] The roughness of regions 550, 560 can be altered for the same reasons as described above for regions 250, 260 on susceptor 200. For example, roughening a region can increase the surface area of ​​that region over its two-dimensional area (e.g., over its area in the XY plane in FIG. 5). The increased surface area increases heat transfer for that region relative to an unroughened region of the same size. Similarly, smoothing (e.g., polishing) a region can reduce the surface area and heat transfer for the region, as described above.

[0050] For susceptors 400, 500 (see FIGS. 4 and 5), the surface roughness of base 201 is modified instead of the surface roughness of the coating described above for susceptors 200 and 300 (see FIGS. 2A-2C and 3). In some embodiments, modifying the surface roughness of base 201, as opposed to the surface roughness of the coating, may be preferred, for example, when modifying the surface roughness of the base is easier (e.g., easier to machine) or can be done with greater precision than modifying the surface roughness of a coating formed over the base. Modifying the roughness of the base may also be used when the susceptor is formed from a single material (e.g., a susceptor monolithically formed from silicon carbide).

[0051] FIG. 6 is a plan view of a first portion 6411 of a susceptor 600 according to another embodiment. The susceptor 600 is the same as the susceptor 200 described above (see FIGS. 2A-2C ), except that the susceptor 600 includes a first portion 6411 of the outer surface 241 of the coating 240 having a different pattern of regions with different average levels of roughness compared to the first portion 2411 of the susceptor 200 shown in FIG. 2C . The first portion 6411 of the susceptor 600 is the same size as the first portion 2411 of the susceptor 200 and is in the same location on the base 201. Referring to FIGS. 2A and 6 , the first portion 6411 of the outer surface 241 of the susceptor 600 is located on the central portion 203 and outer portion 204 of the inner dish 202.

[0052] The first portion 6411 includes a first region 650. The first portion 6411 includes a set of regions 661-664. The set of regions 661-664 are separated from one another by the first region 650. The first region 650 can surround each of the regions 661-664. Each of the individual regions 650 and 661-664 can cover a significant portion of the first portion 6411 of the outer surface 241 of the coating 240. For example, in some embodiments, each individual region 650 and 661-664 can cover at least 5%, at least 10%, at least 15%, or at least 25% of the area corresponding to the front surface 208 of the inner dish 202.

[0053] A susceptor such as susceptor 600 including a coating with multiple non-ring-shaped regions having at least two or more substantially different average levels of roughness can be useful for processes in which the susceptor does not rotate during the process. Although regions 661-664 are shown as rectangles, regions 661-664 can have any shape, including irregular shapes.

[0054] The shapes and locations of regions having different average levels of roughness for each of the susceptors 200-600 described above may be based on (1) the components in the processing chamber in which the susceptor is used, (2) different configurations for a given processing chamber (e.g., different susceptor locations), and (3) different processes performed in a given processing chamber. Some examples of components of a given processing chamber that can cause temperature non-uniformities that can be addressed using the susceptors described herein include (1) the lamp layout in the processing chamber, (2) the relative uniformity of radiation reflected by the processing chamber's reflectors, and (3) the gas flows in the processing chamber, including the gas flows of precursor gases and cooling gases.

[0055] In some embodiments, the susceptor can include non-ring-shaped regions (e.g., regions 661-664) and one or more ring-shaped regions (e.g., third region 263 from FIG. 2C). This can be useful, for example, when the susceptor is not rotated and still has non-uniformities near the edge of the substrate during processing.

[0056] 2A-6 provide one example of a susceptor having one surface modified to have a different average level of roughness, the benefits of the present disclosure may be used to modify two or more surfaces of a given susceptor to improve the uniformity of a process performed on the susceptor. For example, in one embodiment, the outer surface 241 of the coating 240 is modified to have regions on the front surface 208 of the inner dish 202 with different average levels of roughness (see, e.g., FIG. 2A) and regions on the back surface 209 of the inner dish 202 with different average levels of roughness (see, e.g., FIG. 3). In another embodiment, the outer surface of the front surface 208 (see, e.g., FIG. 4) and the back surface 209 of the base 201 (see, e.g., FIG. 5) are each modified to have regions with different average levels of roughness. In yet another embodiment, the coating 240 and the front and back surfaces of the base 201 are each modified to have areas with different average levels of roughness, such that there are four different surfaces on the susceptor with areas with different average levels of roughness.

[0057] In another embodiment, one or more regions have an average level of roughness that varies gradually across the region. For example, in one embodiment, an intermediate region (e.g., first region 261 in FIG. 2C ) is located between a first region (e.g., first region 251) and a second region (e.g., second region 252), and the average level of roughness in the intermediate region may taper from a first average level of roughness (e.g., 40 μm) at the boundary between the intermediate region and the first region to a second average level of roughness (e.g., 80 μm) at the boundary between the intermediate region and the second region. In another embodiment, the average level of roughness in the region may increase from the region's boundaries and reach a maximum value at an intermediate location (e.g., center) of the region between the boundaries. In another embodiment, the average level of roughness in the region may decrease from the region's boundaries and reach a minimum value at an intermediate location (e.g., center) of the region between the boundaries. Other profiles of varying roughness within the region may be provided without departing from the scope of the present disclosure.

[0058] While most of this disclosure has described susceptors including a base and a coating, the benefits described above may also apply to susceptors formed from a single material (e.g., monolithically formed silicon carbide susceptors). In the case of susceptors formed from a single material, the roughness of the outer surface may be modified in a manner similar to that described for the susceptors disclosed above. Furthermore, although the benefits of this disclosure regarding roughness modification are described as applying to susceptors used for deposition including an outer rim and a recessed inner dish, these roughness modification benefits may apply to any component used to support a substrate during a process, including (1) susceptors having different shapes (e.g., a substantially flat, disk-shaped susceptor), (2) susceptors used for different processes (e.g., a susceptor used for a pre-cleaning process), (3) devices capable of supporting two or more substrates (e.g., a wafer boat), or (4) any other substrate support, including a substrate support permanently fixed in a corresponding processing chamber.

[0059] While the forgoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof.

Claims

1. 1. A susceptor for processing a substrate, comprising: an outer rim having an inner edge, an outer edge, and a top connecting said inner edge to said outer edge; an inner dish disposed within and coupled to the outer rim; a base comprising: an inner dish recessed from the top of the outer rim, the inner dish having a front surface and an opposite back surface; a coating formed over the base, the coating having an outer surface including a first portion formed over the front surface of the inner dish; the first portion of the outer surface of the coating includes a first region and a second region; the first region having a first average level of roughness; the second region having a second average level of roughness; the first average level of roughness is at least 50% greater than or 33% less than the second average level of roughness; Coating and The susceptor comprises:

2. The susceptor of claim 1 , wherein the first region and the second region are each ring-shaped regions.

3. The susceptor of claim 1 , wherein the first portion of the outer surface further includes a third region spaced from the first region by the second region.

4. The susceptor of claim 3 , wherein the first region, the second region, and the third region are each ring-shaped regions.

5. The susceptor of claim 3 , wherein the second region surrounds the first region and the third region.

6. The susceptor of claim 3 , wherein the third region has a third average level of roughness that is substantially different from the first average level of roughness and the second average level of roughness.

7. The susceptor of claim 3 , wherein the third region has an average level of roughness that is substantially the same as the first average level of roughness.

8. 2. The susceptor of claim 1, wherein the first average level of roughness is at least 10 times greater than or 10 times less than the second average level of roughness.

9. 1. A susceptor for processing a substrate, comprising: an outer rim having an inner edge, an outer edge, and a top connecting said inner edge to said outer edge; an inner dish disposed within and coupled to the outer rim; a base comprising: an inner dish recessed from the top of the outer rim, the inner dish having a front surface and an opposite back surface; a coating formed over the base, the coating having an outer surface including a first portion formed over the back surface of the inner dish; the first portion of the outer surface of the coating includes a first region and a second region; the first region having a first average level of roughness; the second region having a second average level of roughness; the first average level of roughness is at least 50% greater than or 33% less than the second average level of roughness; Coating and The susceptor comprises:

10. 10. The susceptor of claim 9, wherein the first region and the second region are each ring-shaped regions.

11. The susceptor of claim 9 , wherein the first portion of the outer surface further includes a third region spaced from the first region by the second region.

12. The susceptor of claim 11 , wherein the first region, the second region, and the third region are each ring-shaped regions.

13. The susceptor of claim 11 , wherein the second region surrounds the first region and the third region.

14. 12. The susceptor of claim 11, wherein the third region has a third average level of roughness that is substantially different from the first average level of roughness and the second average level of roughness.

15. The susceptor of claim 11 , wherein the third region has an average level of roughness that is substantially the same as the first average level of roughness.

16. 10. The susceptor of claim 9, wherein the first average level of roughness is at least 10 times greater than or 10 times less than the second average level of roughness.

17. 1. A susceptor for processing a substrate, comprising: an outer rim having an inner edge, an outer edge, and a top connecting said inner edge to said outer edge; an inner dish disposed within and coupled to the outer rim; the inner dish is recessed from the top of the outer rim, the inner dish having a front surface and an opposite back surface; an outer surface of the base including a first portion on the front surface of the base or the back surface of the base; the first portion includes a first region and a second region; the first region having a first average level of roughness; the second region having a second average level of roughness; the first average level of roughness is at least 50% greater than or 33% less than the second average level of roughness; base The susceptor comprises:

18. 18. The susceptor of claim 17, wherein the first portion of the outer surface of the base is on the front surface of the base.

19. The susceptor of claim 17 , wherein the first portion of the outer surface of the base is on the back surface of the base.

20. the first portion of the outer surface further includes a third region spaced from the first region by the second region; the third region having a third average level of roughness substantially different from the second average level of roughness; The susceptor of claim 17.

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