Flush ring for a support assembly

Abstract

Support assemblies, a purge ring for a support assembly, and a processing method for increasing the residence time of edge purge gas in a heated support assembly are described. The purge ring has an inner diameter face and an outer diameter face defining a thickness of the purge ring, a top surface and a bottom surface defining a height of the purge ring, and a thermal expansion feature. The purge ring includes a plurality of apertures extending through the thickness and circumferentially aligned with a plurality of circumferentially spaced purge outlets in a substrate support.

Description

Technical Field

[0001] The embodiments described herein generally relate to devices for support assemblies. In particular, embodiments of this disclosure are flushing rings for heated support assemblies. Background Technology

[0002] In semiconductor wafer processing chambers such as atomic layer deposition (ALD) chambers or chemical vapor deposition (CVD) chambers, wafer backside pressure control and edge flushing offer advantages for wafer processing. Wafer backside pressure control provides improved wafer temperature uniformity. Edge flushing prevents deposition on the wafer backside and curved edges.

[0003] Traditional backside pressure control is achieved via a sealing strip on the support surface near the wafer edge. The gas flow path passes through the support to the bag behind the wafer and enters the sealing strip. Pressure control is accomplished by controlling the flow rate, measuring pressure, and having a flow path that bypasses the chamber to the pump.

[0004] Traditional edge flushing can be achieved using several different techniques. Gas can be delivered through piping within a support and distributed to the underside of the wafer edge via recursive channels, gas chambers near the support circumference, or a combination of both. This technique requires an edge ring design surrounding the wafer to guide gas flow. The edge ring can be integrated into the support or be a separate component. The effectiveness of edge flushing techniques is limited by the quality of flow distribution around the wafer edge.

[0005] Argon (Ar) is a commonly used gas for edge flushing. Although argon (Ar) flows through a heater during edge flushing, the support assembly setpoint temperature is typically lower than the wafer temperature. Therefore, commonly used edge flushing equipment and methods experience a cooling effect at the wafer edge, which can lead to a reduction in film thickness. Increasing the residence time of argon (Ar) has been found to increase the flow temperature of argon (Ar). Therefore, there is a need in the art for improved edge flushing equipment and methods to reduce the cooling effect at the wafer edge.

[0006] Therefore, a flushing ring is needed to reduce the cooling effect at the wafer edge by increasing the residence time of argon (Ar). Summary of the Invention

[0007] One or more embodiments of this disclosure are a support assembly including: a substrate support having a support surface and an outer peripheral wall, the support surface having an outer edge, and the outer peripheral wall having a top surface and an outer peripheral surface. The outer peripheral wall includes a plurality of circumferentially spaced flushing outlets extending radially inward from the outer peripheral surface into the substrate support, the top surface of the wall being below the support surface. The support assembly includes a flushing ring having an inner diameter surface and an outer diameter surface defining the thickness of the flushing ring, and a top surface and a bottom surface defining the height of the flushing ring. The flushing ring includes a plurality of apertures extending through the thickness and circumferentially aligned with the plurality of circumferentially spaced flushing outlets.

[0008] An additional embodiment of this disclosure is a processing method comprising the steps of increasing the residence time of edge flushing gas in a heated support assembly by incorporating a flushing ring around the outer peripheral surface of a ledge of a substrate support. The flushing ring has an inner diameter surface and an outer diameter surface defining the thickness of the flushing ring, and a top surface and a bottom surface defining the height of the flushing ring. The flushing ring includes a plurality of orifices extending through the thickness and circumferentially aligned with a plurality of circumferentially spaced flushing outlets in the substrate support.

[0009] A further embodiment of this disclosure is a flushing ring for a substrate support bracket. The flushing ring includes: an inner diameter surface and an outer diameter surface defining the thickness of the flushing ring in the range of 1 mm to 5 mm; a top surface and a bottom surface defining the height of the flushing ring; thermal expansion features; and a plurality of pores, the plurality of pores ranging from 6 to 36 pores. Each of the plurality of pores is circular, the circle having a diameter in the range of 20 mil to 50 mil, each of the plurality of pores extending through the thickness of the flushing ring and circumferentially aligned with a plurality of circumferentially spaced flushing outlets in the substrate support bracket. The substrate support bracket and the flushing ring include complementary alignment features configured to cooperatively interact to align the plurality of pores with the plurality of circumferentially spaced flushing outlets. The flushing ring has an inner diameter that, at a temperature of 375 degrees Celsius, is 0.5 mil to 5 mil larger than the outer diameter of the outer peripheral surface of the substrate support bracket. Attached Figure Description

[0010] To gain a more detailed understanding of the features described above, a more specific description of the disclosure, which has been briefly summarized above, can be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only typical embodiments of the disclosure and should not be considered as limiting its scope, as other equivalent embodiments are permissible.

[0011] Figure 1 The illustration shows a cross-sectional view of a flushing ring according to one or more embodiments of the present disclosure;

[0012] Figure 2A The illustration shows a partial cross-sectional view of a flushing ring on a substrate support according to one or more embodiments of the present disclosure;

[0013] Figure 2B The diagram shows Figure 2A Exploded view of the flushing ring;

[0014] Figure 3 This is a cross-sectional view of a support assembly according to one or more embodiments of the present disclosure; and

[0015] Figure 4 The diagram shows Figure 3 A partial cross-sectional view of the disassembled support assembly. Detailed Implementation

[0016] Before describing several exemplary embodiments of this disclosure, it should be understood that this disclosure is not limited to the details of the construction or processing steps set forth in the following description. This disclosure can have other embodiments and can be practiced or performed in various ways.

[0017] As used in this specification and the appended claims, the term "substrate" refers to a surface or a portion thereof on which the treatment is performed. Those skilled in the art will also understand that reference to a substrate may also refer only to a portion of a substrate, unless the context clearly indicates otherwise. Furthermore, reference to deposition on a substrate may refer to both: a bare substrate, and a substrate on which one or more films or features are deposited or formed.

[0018] As used herein, “substrate” means any substrate or material surface formed on a substrate on which a film treatment is performed during manufacturing processes. For example, substrate surfaces on which treatments can be performed include materials such as silicon, silicon oxide, strained silicon, silicon-on-insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials, depending on the application. Substrates include, but are not limited to, semiconductor wafers. Substrates may be exposed to pretreatment processes such as polishing, etching, reduction, oxidation, hydroxylation, annealing, UV curing, electron beam curing, and / or baking of the substrate surface. In addition to performing film treatments directly on the surface of the substrate itself, any of the disclosed film treatment steps may be performed on an underlayer formed on the substrate, as disclosed in more detail below, and the term “substrate surface” is intended to include such an underlayer as indicated by the context. Thus, for example, when a film / layer or a portion of a film / layer has already been deposited onto the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0019] As used in this specification and the appended claims, "substrate support" and "substrate support bracket" are used interchangeably.

[0020] As used in this specification and the appended claims, the use of related terms such as “above” and “below” should not be construed as limiting the scope of this disclosure to physical orientation in space. Accordingly, the use of relative terms should not be limited to directions specified by gravity.

[0021] Embodiments of this disclosure relate to support heater designs to provide a uniform temperature distribution on a wafer across a range of operating temperatures (e.g., 150°C to 550°C). Some embodiments provide support heaters having multiple heating zones (e.g., three zones). In some embodiments, multi-zone heaters allow for localized profile tuning at the heater center and / or edges. Some embodiments provide flushing rings with increased thermal uniformity and / or increased flushing efficiency.

[0022] refer to Figure 1 One or more embodiments of this disclosure relate to a flushing ring 100. The flushing ring 100 has an inner diameter surface 110 and an outer diameter surface 120 defining a thickness T of the flushing ring. The inner diameter surface 110 and the outer diameter surface 120 define the thickness T of the flushing ring 100. In some embodiments, the thickness T of the flushing ring 100 is in the range of 1 mm to 5 mm.

[0023] In one or more embodiments, the flushing ring 100 includes a plurality of pores 150 extending through the thickness T. In one or more embodiments, the plurality of pores 150 ranges from 6 to 36 pores. Although the pores 150 illustrated in the figures are generally circular, those skilled in the art will understand that the shape of the pores 150 is not limited to circular openings. In one or more embodiments, the plurality of pores 150 can be any suitable shape, such as circular, square, rectangular, or any other polygon.

[0024] The size of the openings of the orifices 150 on the inner and outer surfaces of the flushing ring 100 can be uniform or vary between and within the openings. For example, the inner opening 151 of the orifice 150 on the inner diameter surface 110 of the flushing ring 100 may have a different size than the outer opening 152 on the outer diameter surface 120 of the flushing ring 100. In one or more embodiments, each of the plurality of orifices 150 has an outer opening 152 on the outer diameter surface 120 that is larger than the inner opening 151 on the inner diameter surface 110. Unless otherwise specified, the diameter of each orifice 150 is measured at the relevant surface of the ring.

[0025] In one or more embodiments, each of the plurality of pores 150 is circular, having a diameter ranging from 10 mil to 80 mil, or from 20 mil to 50 mil. Smaller diameter pores 150 increase back pressure and reduce flow rate, thereby increasing gas residence time. In some embodiments, each of the plurality of pores 150 has a hydraulic diameter ranging from 10 mil to 80 mil, or from 20 mil to 50 mil.

[0026] The flushing ring 100 has a top surface 130 and a bottom surface 140 defining a height H of the flushing ring 100. The flushing ring 100 has a height H that is greater than the diameter of the pore.

[0027] In some embodiments, the flushing ring 100 incorporates an alignment feature 160. The alignment feature 160 is configured to cooperatively interact with alignment features on the separating member to aid in positioning the flushing ring 100 relative to the separating member, allowing the aperture 150 to align with a portion of the separating member, as discussed further below. The alignment feature 160 can be any suitable shape or size to permit cooperative interaction. In the illustrated embodiment, the alignment feature 160 is an arcuate cutout formed in the bottom surface 140 of the flushing ring 100. Those skilled in the art will understand that the alignment feature 160 is not limited to the arcuate cutout illustrated, and other features fall within the scope of this disclosure. For example, Figure 2B The alignment feature 160 shown in the figure is a recess formed in the inner diameter surface 110 of the flushing ring 100.

[0028] In one or more embodiments, the flushing ring 100 includes a thermal expansion feature 170. In one or more embodiments, the thermal expansion feature may be a groove or break located at a predetermined position in the flushing ring 100. Figure 1 In the embodiments illustrated, the thermal expansion feature 170 is a break in the continuity of the flushing ring 100. In some embodiments, the thermal expansion feature 170 does not interrupt the continuity of the flushing ring 100. For example, in some embodiments, the thermal expansion feature 170 includes a region with a reduced thickness T. In some embodiments, the thermal expansion feature 170 has a width ranging from 0.5 mm to 2 mm.

[0029] refer to Figure 2A A partial view of the flushing ring 100 on the substrate support 200 is shown, and a cross-section is illustrated. Figure 2B An enlarged view of a flushing ring 100 on a substrate support 200 is shown. In one or more embodiments, the flushing ring 100 may be removed from the substrate support 200. In some embodiments, the flushing ring 100 is secured to the substrate support 200 in a manner sufficient to limit removal.

[0030] In one or more embodiments, the substrate support 200 has a substrate support surface 210 on which a wafer can be supported during processing. The illustrated substrate support 200 includes an outer peripheral ledge 212 having an outer peripheral surface 211 and a top surface 214 and defining an outer diameter surface 213 of the substrate support surface 210. The top surface 214 is located below the support surface 210.

[0031] The outer peripheral surface 211 of the ledge of the substrate support surface 210 has an outer diameter ranging from 290 mm to 310 mm. In one or more embodiments, when the substrate support 200 and the rinsing ring 100 are at a temperature of 300°C to 500°C, the rinsing ring 100 has an inner diameter ranging from 0.5 mil to 5 mil larger than the outer diameter of the outer peripheral surface 211 of the ledge of the substrate support surface 210. In one or more embodiments, increasing the temperature of the substrate support 200 and the rinsing ring 100 reduces the difference between the inner diameter of the rinsing ring 100 and the outer peripheral surface 211 of the ledge.

[0032] The outer peripheral surface 211 has a plurality of circumferentially spaced flushing outlets 220 extending radially inward from the outer peripheral surface 211 into the substrate support 200. In the illustrated embodiment, the circumferentially spaced flushing outlets 220 extend from the outer peripheral surface 211 into flushing channels 222 within the substrate support 200. In some embodiments, the flushing channels 222 include one or more channels formed in the bottom of the upper portion of the substrate support, which form a closed space when the upper portion engages with the lower portion of the substrate support. Those skilled in the art will understand how the substrate support can be formed by engaging the upper and lower portions.

[0033] In one or more embodiments, each of the plurality of apertures 150 of the flushing ring 100 is aligned with one of the circumferentially spaced flushing outlets 220 in the substrate support 200. In one or more embodiments, the substrate support 200 and the flushing ring 100 further include complementary alignment features 160 configured to cooperatively interact to align the plurality of apertures 150 with the plurality of circumferentially spaced flushing outlets 220. For example, in Figure 2B In the embodiment illustrated, the alignment feature 160 includes a recess formed in the inner diameter surface of the flushing ring and a complementary protrusion formed in the outer peripheral surface 211 of the ledge of the substrate support 200.

[0034] Figure 3 The illustration shows a cross-sectional view of a portion of a processing chamber including a substrate support 200, a nozzle 320, and a spacer ring 310. In the illustrated embodiment, the substrate support 200 includes a rinsing ring 100 and an edge ring 260, as shown. Figure 4The enlarged view of region IV shown is illustrated. In some embodiments, the substrate support 200 is configured as an electrostatic chuck. In some embodiments, one or more electrodes are located within the thickness of the support base 204 and configured to form an electrostatic chuck. In some embodiments, one or more electrodes are located at an electrode depth (not shown) from the bottom surface of the substrate support 200. In some embodiments, one or more electrodes are configured as a unipolar electrostatic chuck. In some embodiments, one or more electrodes are configured as a bipolar electrostatic chuck. One or more electrodes may be connected to one or more power sources (not shown) to polarize the electrodes to act as an electrostatic chuck.

[0035] In one or more embodiments, the support assembly 300 includes a support base 204 having a top surface. In one or more embodiments, the substrate support 200 includes a heater 202 on the top surface of the support base 204.

[0036] Figure 4 The diagram shows... Figure 3 An enlarged view of region IV. In one or more embodiments, the substrate support 200 has an outer peripheral ledge 212, which has a ledge top surface 214 and a ledge outer peripheral surface 211. The outer peripheral ledge 212 has a plurality of circumferentially spaced flushing outlets 220 extending radially inward from the ledge outer peripheral surface 211 into the substrate support 200. In one or more embodiments, the ledge top surface 214 is below the substrate support surface 210.

[0037] exist Figure 3 and 4 In the illustrated embodiment, the edge ring 260 is placed on the outer peripheral portion of the top surface 205 of the support base 204. In one or more embodiments, the edge ring 260 has a flushing surface 270 extending inwardly on the top surface 214 of the ledge to a flushing inner surface 272 spaced apart from the outer edge 215 of the support surface, forming an edge flushing flow path 280 between the outer peripheral surfaces 211 of the ledge, through the flushing ring 100, and between the top surface 214 of the ledge and the flushing surface 270, and between the outer edge 215 of the support surface and the flushing inner surface 272. In one or more embodiments, the flushing inner surface 272 is adjacent to the outer edge 215 of the support surface.

[0038] Some embodiments provide a processing method that includes increasing the residence time of edge flushing gas in the heated support assembly 300. In one or more embodiments, the processing method includes incorporating a flushing ring 100 around the outer peripheral surface 211 of the ledge of the substrate support 200. In one or more embodiments, the edge flushing gas includes argon (Ar).

[0039] In one or more embodiments, the edge flushing gas containing argon (Ar) has a specific heat of 312 degrees Celsius. In one or more embodiments, specific heat is the amount of heat required to increase the temperature of a unit mass by 1 degree Celsius. In one or more embodiments, a heated support assembly 300 with a flushing ring 100 can increase the specific heat of argon (Ar) at a faster rate than a heated support assembly without a flushing ring.

[0040] In one or more embodiments, incorporating the flushing ring 100 into the heated support assembly 300 includes aligning alignment features on the flushing ring 100 with complementary alignment features on the substrate support 200. In one or more embodiments, the flushing ring 100 increases the residence time of argon (Ar). In one or more embodiments, the residence time of argon (Ar) is in the range of 0.4 to 0.55 seconds in the absence of the flushing ring. In one or more embodiments, the residence time of argon (Ar) is in the range of 0.6 to 0.7 seconds when the flushing ring 100 is present and each of the plurality of pores 150 has a diameter of 40 mil. In one or more embodiments, the residence time of argon (Ar) is in the range of 0.7 to 0.8 seconds when the flushing ring 100 is present and each of the plurality of pores 150 has a diameter of 30 mil.

[0041] In one or more embodiments, the residence time of the edge flushing gas in the heated support assembly can be varied by changing the size of the plurality of orifices 150. In one or more embodiments, when the size of the plurality of orifices 150 is smaller, the residence time of the edge flushing gas in the heated support assembly is increased.

[0042] In one or more embodiments, the edge temperature of the substrate support 200 with the rinsing ring 100 is 2 to 5 degrees Celsius higher than the edge temperature of the substrate support 200 without the rinsing ring. In one or more embodiments, the center temperature of the substrate support 200 with the rinsing ring 100 is 5 to 10 degrees Celsius higher than the center temperature of the substrate support 200 without the rinsing ring. In one or more embodiments, when the rinsing ring 100 is present and each of the plurality of apertures 150 has a diameter of 40 mil, the argon (Ar) temperature is 5 to 15 degrees Celsius higher than the argon (Ar) temperature without the rinsing ring. In one or more embodiments, when the rinsing ring 100 is present and each of the plurality of apertures 150 has a diameter of 30 mil, the argon (Ar) temperature is 15 to 50 degrees Celsius higher than the argon (Ar) temperature without the rinsing ring.

[0043] In one or more embodiments, each of the plurality of channels has a channel volume. In one or more embodiments, the temperature of the channel volume of each of the plurality of channels is different. In one or more embodiments, the temperature of the channel volume of each of the plurality of channels is the same. In one or more embodiments, the temperature of the channel volume of each of the plurality of channels without a flushing ring is in the range of 200 degrees Celsius to 250 degrees Celsius. In one or more embodiments, when a flushing ring 100 is present and each of the plurality of orifices 150 has a diameter of 40 mil, the temperature of the channel volume is in the range of 250 degrees Celsius to 300 degrees Celsius. In one or more embodiments, when a flushing ring 100 is present and each of the plurality of orifices 150 has a diameter of 30 mil, the temperature of the channel volume is in the range of 300 degrees Celsius to 350 degrees Celsius.

[0044] In one or more embodiments, the edge flushing gas flowing through the edge flushing flow path 280 has a temperature greater than or equal to 15 degrees Celsius higher than the gas flowing through an edge flushing flow path without a flushing ring. In one or more embodiments, the edge flushing gas flowing through the edge flushing flow path 280 has a temperature greater than or equal to 10 degrees Celsius, 5 degrees Celsius, 4 degrees Celsius, 3 degrees Celsius, 2 degrees Celsius, or 1 degree Celsius higher than the gas flowing through an edge flushing flow path without a flushing ring.

[0045] In one or more embodiments, a low-pressure zone is formed in the pouch portion below the edge ring. In one or more embodiments, the processing method includes reducing the volume of the pouch portion below the edge ring. In one or more embodiments, reducing the volume of the pouch portion below the edge ring eliminates the low-pressure zone. In one or more embodiments, the flushing ring 100 can be placed on the substrate support 200 in a manner that reduces the size of the pouch portion below the edge ring. In one or more embodiments, reducing the size of the pouch portion below the edge ring increases the residence time of argon (Ar).

[0046] Throughout this specification, references to "an embodiment," "some embodiments," "one or more embodiments," or "an embodiment" indicate that a particular feature, structure, material, or characteristic described in connection with an embodiment is included in at least one embodiment of this disclosure. Therefore, phrases such as "in one or more embodiments," "in some embodiments," "in one embodiment," or "in one embodiment" appearing in various places throughout the specification do not necessarily refer to the same embodiment of this disclosure. Furthermore, particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0047] Although the disclosure herein has been described with reference to specific embodiments, those skilled in the art will understand that the described embodiments are merely illustrative of the principles and applications of this disclosure. Various modifications and variations to the methods and apparatus of this disclosure will be apparent to those skilled in the art without departing from the spirit and scope of this disclosure. Therefore, this disclosure may include modifications and variations within the scope of the appended claims and their equivalents.

Claims

1. A support assembly, comprising: A substrate support member having a support surface and an outer peripheral wall, the support surface having an outer edge, the outer peripheral wall having a top surface and an outer peripheral surface, the outer peripheral wall having a plurality of circumferentially spaced flushing outlets extending radially inward from the outer peripheral surface into the substrate support member, the top surface of the wall being below the support surface. and A flushing ring having an inner diameter surface and an outer diameter surface defining the thickness of the flushing ring, and a top surface and a bottom surface defining the height of the flushing ring, the flushing ring including a plurality of apertures extending through the thickness and aligned circumferentially with the plurality of circumferentially spaced flushing outlets. Each of the plurality of pores is circular and has a diameter ranging from 10 mil to 80 mil.

2. The support assembly according to claim 1, wherein the plurality of pores has a range of 6 to 36 pores.

3. The support assembly of claim 1, wherein each of the apertures in the flushing ring is aligned with one of the circumferentially spaced flushing outlets in the substrate support.

4. The support assembly of claim 1, wherein the substrate support and the flushing ring further include complementary alignment features configured to cooperate in interacting to align the plurality of orifices with the plurality of circumferentially spaced flushing outlets.

5. The support assembly of claim 1, wherein the flushing ring further includes a thermal expansion feature.

6. The support assembly of claim 1, wherein the flushing ring is removable from the substrate support.

7. The support assembly of claim 1, wherein the flushing ring has a thickness in the range of 1 mm to 5 mm.

8. The support assembly according to claim 1, wherein when the base plate support and the flushing ring are at a temperature of 375 degrees Celsius, the flushing ring has an inner diameter ranging from 0.5 mil to 5 mil larger than the outer diameter of the outer peripheral surface of the wall frame.

9. The support assembly of claim 1, wherein each of the plurality of pores in the flushing ring has a hydraulic diameter in the range of 10 mil to 80 mil.

10. The support assembly of claim 1, wherein each of the plurality of apertures is a circle having a diameter in the range of 20 mil to 50 mil.

11. The support assembly of claim 10, wherein each of the plurality of apertures has an opening in the outer diameter surface that is larger than that in the inner diameter surface, and the diameter of each of the apertures is measured in the inner diameter surface.

12. The support assembly of claim 1, further comprising a support base having a top surface, and the substrate support having a plurality of recesses formed in a bottom surface of the substrate support such that, when the substrate support is connected to the support base, the plurality of recesses form a plurality of channels to allow gas to flow through the substrate support to the plurality of circumferentially spaced flushing outlets.

13. The support assembly of claim 12, further comprising an edge ring disposed on an outer peripheral portion of the top surface of the support base, the edge ring having a flushing surface extending inwardly on the top surface of the ledge to a flushing inner surface, the flushing inner surface being spaced apart from the outer edge of the support surface by a distance to form an edge flushing flow path between the outer peripheral surfaces of the ledge, through the flushing ring, and between the top surface of the ledge and the flushing surface, and between the outer edge of the support surface and the flushing inner surface.

14. The support assembly of claim 13, wherein the gas flowing through the edge flushing flow path has a temperature greater than or equal to 15 degrees Celsius higher than the gas flowing through the edge flushing flow path without the flushing ring.

15. The support assembly of claim 1, wherein the base plate support includes a heater.

16. A processing method comprising increasing the residence time of edge flushing gas in a heated support assembly by incorporating a flushing ring around the outer peripheral surface of a ledge of a substrate support, the flushing ring having an inner diameter surface and an outer diameter surface defining the thickness of the flushing ring, and a top surface and a bottom surface defining the height of the flushing ring, the flushing ring including a plurality of orifices extending through the thickness and circumferentially aligned with a plurality of circumferentially spaced flushing outlets in the substrate support. Each of the plurality of pores is circular and has a diameter ranging from 10 mil to 80 mil.

17. The processing method of claim 16, wherein the plurality of pores in the flushing ring are in the range of 6 to 36, and each of the pores is aligned with one of the circumferentially spaced flushing outlets.

18. The processing method according to claim 16, wherein the step of combining the flushing ring includes the following steps: Align the alignment features on the flushing ring with the complementary alignment features on the substrate support.

19. The processing method of claim 18, wherein the flushing ring further comprises a thermal expansion feature.

20. A flushing ring for a substrate support, the flushing ring comprising: The inner and outer diameter surfaces define the thickness of the flushing ring in the range of 1 mm to 5 mm, the top and bottom surfaces define the height of the flushing ring, and thermal expansion characteristics. A plurality of pores, the plurality of pores ranging from 6 to 36 pores, each of the plurality of pores being circular, the circle having a diameter ranging from 20 mil to 50 mil, each of the plurality of pores extending through the thickness of the flushing ring and circumferentially aligned with a plurality of circumferentially spaced flushing outlets in the substrate support, wherein the substrate support and the flushing ring include complementary alignment features configured to cooperatively interact to align the plurality of pores with the plurality of circumferentially spaced flushing outlets; and The inner diameter, when the substrate support and the flushing ring are at a temperature of 375 degrees Celsius, is in the range of 0.5 mil to 5 mil larger than the outer diameter of the outer perimeter of the base plate support.

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