Pedestal shroud for directing the flow of process gases and process by-products within a substrate processing system - Patents.com

Abstract

A station of a substrate processing system includes a pedestal and a shroud. The pedestal is disposed within a well of the station. The pedestal includes a base for supporting a substrate and a stem extending from the base into the well of the station. The shroud is coupled to the base of the pedestal. The shroud surrounds the base and extends along the stem into the well of the station. The station further includes a liner covering an inner sidewall of the well of the station. The station further includes a liner covering a pedestal-facing surface of a bottom of the well of the station. The station further includes a hollow object disposed within the well of the station. The hollow object is of smaller dimensions than the well of the station.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims priority to Indian Patent Application No. 202211012613, filed on March 8, 2022. The disclosures of the above-referenced applications are hereby incorporated by reference in their entireties.

[0002] The present disclosure relates generally to substrate processing systems, and more particularly to a pedestal shroud that directs the flow of process gases and process by-products within a substrate processing system. [Background technology]

[0003] The background description provided herein is intended to provide a general overview of the contents of the present disclosure. Work by the currently named inventors within the scope of what is described in this background section, as well as aspects of the description that may not otherwise be considered prior art at the time of filing, are not admitted, expressly or impliedly, as prior art against the present disclosure.

[0004] Atomic layer deposition (ALD) is a thin film deposition method in which gas chemical processes are performed sequentially to deposit a thin film on a surface of a material (e.g., the surface of a substrate such as a semiconductor wafer). A typical ALD process includes multiple alternating and purge cycles (e.g., dose, purge, dose, purge, etc.) that are repeated in rapid succession. In most ALD reactions, at least two chemicals, called precursors (reactants), are used to react the surface of the material with one precursor at a time in a sequential, self-limiting manner. For example, a first reactant is provided during a first dose cycle. The first dose cycle is followed by a purge cycle. A second reactant may then be provided during a second dose cycle. The second dose cycle is followed by a purge cycle, and so on. By repeatedly exposing the material to different precursors during the dose cycles, a thin film is gradually deposited on the surface of the material.

[0005] Thermal ALD (T-ALD) is carried out in a heated processing chamber. The processing chamber is maintained at sub-atmospheric pressure using a vacuum pump and a controlled flow of inert gas. The substrate to be coated with the ALD film is placed in the processing chamber and allowed to equilibrate to the temperature of the processing chamber before starting the ALD process. Summary of the Invention

[0006] A station of a substrate processing system includes a pedestal and a shroud. The pedestal is disposed within a well of the station. The pedestal includes a base for supporting a substrate and a stem extending from the base into the well of the station. The shroud is coupled to the base of the pedestal. The shroud surrounds the base and extends along the stem into the well of the station.

[0007] In a further feature, the station further comprises a liner covering an inner sidewall of the well of the station.

[0008] In a further feature, the station further comprises a liner covering a bottom, pedestal-facing surface of the well of the station.

[0009] In a further feature, the station further comprises a hollow object disposed in the well of the station, the hollow object being of smaller dimensions than the well of the station.

[0010] In a further feature, the station further comprises a first liner, a second liner, and a hollow object. The first liner covers an inner sidewall of a well of the station. The second liner covers a bottom pedestal-facing surface of the well. The hollow object is disposed within the well. The well and the first liner are greater in height than the hollow object.

[0011] In a further feature, the well comprises an exhaust port, the station further comprises a third liner covering the exhaust port, the first and second liners mating with the third liner.

[0012] In a further feature, the second liner is annular with an outer edge contacting the first liner and an inner edge contacting the hollow object.

[0013] In a further feature, a gap is maintained between the first liner and the shroud.

[0014] In a further feature, the shroud, the first and second liners, the hollow body, the well, and the pedestal are concentric.

[0015] In a further feature, the hollow body includes an outer sidewall having a smaller diameter than the first liner and an inner sidewall having a larger diameter than the stem portion of the seat, the first liner being taller than the hollow body.

[0016] In a further feature, the second liner and the well each include a central opening, and the stem of the seat passes through the inner sidewall of the hollow body and through the opening of the second liner and the well.

[0017] In a further feature, the well comprises an exhaust port and an inlet for gas. The gas flows around the hollow object and exits the well through the exhaust port.

[0018] In a further feature, the station further comprises a third liner covering the exhaust port and mating with the first and second liners.

[0019] In a further feature, the station further comprises an edge ring disposed about a base of the pedestal, the shroud being attached to the edge ring with a gap maintained between the shroud and the edge ring.

[0020] In a further feature, the well comprises a first liner, a second liner, a hollow object, an exhaust port, and an inlet. The first liner covers an inner sidewall of the well. The second liner covers a bottom pedestal-facing surface of the well. The hollow object is disposed within the well. The well and the first liner are greater in height than the hollow object. Gas enters the well through the gap and the inlet, flows around the hollow object, and exits the well through the exhaust port.

[0021] In a further feature, the station further comprises a third liner covering the exhaust port and mating with the first and second liners.

[0022] In a further feature, the well includes an exhaust port. The station further includes a first liner, a second liner, and a third liner. The first liner covers an inner sidewall of the well. The second liner covers a bottom pedestal-facing surface of the well. The third liner covers the exhaust port and connects with the first and second liners.

[0023] In a further feature, the station further comprises a hollow object disposed within the well. The hollow object is of smaller dimensions than the well. The first liner has a height greater than the hollow object. The second liner is annular with an outer edge contacting the first liner and an inner edge contacting the hollow object.

[0024] In a further feature, the station further comprises an edge ring disposed about a base of the pedestal. The shroud is attached to the edge ring with a gap maintained between the shroud and the edge ring. The well comprises an inlet. Gas enters the well through the gap and the inlet, flows around the hollow object, and exits the well through an exhaust port.

[0025] In a further feature, the station further comprises an object comprising an outer sidewall, an inner sidewall, and a first surface connecting a first end of the outer sidewall and the inner sidewall. The object is placed on a second surface of a bottom of the well, the second surface being opposite the first surface. The height of the object is less than the depth of the well of the station.

[0026] In a further feature, the station further comprises a first liner and a second liner. The first liner covers an inner sidewall of the well. The second liner covers a second surface of a bottom of the well. The first liner is taller than the object. The second liner is annular with an outer edge contacting the first liner and an inner edge contacting an outer sidewall of the object.

[0027] In a further feature, the inner sidewall of the object is shorter than the outer sidewall of the object and does not contact the second surface of the bottom of the well.

[0028] In a further feature, the station further comprises a plurality of lift pin assemblies supporting the substrate. The object includes a recess in which the lift pin assemblies are positioned.

[0029] In a further feature, the well includes a plurality of openings along a pedestal-facing edge of the well for accessing the lift pin assembly. The first liner includes a protrusion extending radially outwardly and covering the openings.

[0030] In a further feature, the station further comprises a heat shield coupled to an end of the base opposite the well. A shroud surrounds the heat shield.

[0031] In a further feature, the well includes an exhaust port. The station further includes a first liner and a second liner. The first liner covers the exhaust port. The second liner covers an inner sidewall of the well and mates with the first liner.

[0032] In a further feature, the station further comprises a third liner covering a bottom, pedestal-facing surface of the well and mating with the first and second liners.

[0033] In a further feature, the station further comprises a hollow object disposed in the well. The well and the second liner have a height greater than the hollow object.

[0034] In a further feature, the third liner is annular with an outer edge contacting the second liner and an inner edge contacting the hollow object.

[0035] In a further feature, the station further comprises an edge ring disposed about a base of the pedestal. The shroud is attached to the edge ring with a gap maintained between the shroud and the edge ring. The well comprises an inlet. Gas enters the well through the gap and the inlet, flows around the hollow object, and exits the well through an exhaust port.

[0036] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and specific examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. [Brief description of the drawings]

[0037] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0038] [Figure 1] FIG. 1 shows a plan view of an example substrate processing system (tool) that includes multiple stations for processing substrates.

[0039] [Diagram 2] FIG. 2 shows an example of a cross-sectional view of a station of the tool of FIG.

[0040] [Figure 3A]FIG. 3A illustrates an example cross-sectional view of the station of FIG. 2, further including a shroud according to the present disclosure, a wall liner for the well of the station, an annular bottom liner for the well, and a reducing vessel for the well.

[0041] [Figure 3B] FIG. 3B shows an example of the gas flow for the station of FIG. 3A.

[0042] [Figure 4A] FIG. 4A illustrates an example cross-sectional view of the station of FIG. 2, further including a shroud according to the present disclosure, a wall liner, and a disk-shaped bottom liner for the well, and without a reduction vessel.

[0043] [Figure 4B] FIG. 4B shows an example of gas flow for the station of FIG. 4A.

[0044] [Figure 5A] FIG. 5A shows a perspective view of the well of the station of FIG. 2, showing an exhaust port within the well, with a port liner for the exhaust port according to the present disclosure.

[0045] [Figure 5B] FIG. 5B shows a perspective view of an example port liner according to the present disclosure.

[0046] [Figure 6] FIG. 6 shows a perspective view of an example of an annular bottom liner for a well according to the present disclosure.

[0047] [Figure 7A] FIG. 7A shows a top perspective view of a disk-shaped bottom liner for a well according to the present disclosure. [Figure 7B] FIG. 7B shows a bottom perspective view of a disk-shaped bottom liner for a well according to the present disclosure.

[0048] [Figure 8]FIG. 8 shows a perspective view of a well comprising the port liner of FIG. 5B and the disk-shaped bottom liner of FIGS. 7A and 7B in accordance with the present disclosure.

[0049] [Figure 9A] FIG. 9A shows a front perspective view of a first section of a wall liner according to the present disclosure. [Figure 9B] FIG. 9B shows a rear perspective view of a first section of a wall liner according to the present disclosure.

[0050] [Figure 10A] FIG. 10A shows a front perspective view of a second section of a wall liner according to the present disclosure. [Figure 10B] FIG. 10B shows a rear perspective view of a second section of a wall liner according to the present disclosure.

[0051] [Figure 11] FIG. 11 shows a perspective view of a well comprising the port liner of FIG. 5B, the disk-shaped bottom liner of FIGS. 7A and 7B, and the wall liners of FIGS. 9A-10B in accordance with the present disclosure.

[0052] [Figure 12A] FIG. 12A shows a top perspective view of a reducing container for a well according to the present disclosure. [Figure 12B] FIG. 12B shows a bottom perspective view of a reducing container for a well according to the present disclosure.

[0053] [Figure 13] FIG. 13 shows a perspective view of a well including the port liner of FIG. 5B, the annular or disk-shaped bottom liner of FIGS. 6-7B, the wall liner of FIGS. 9A-10B, and the reduced volume of FIGS. 12A and 12B according to the present disclosure.

[0054] [Figure 14] FIG. 14 illustrates an example of a shroud according to the present disclosure.

[0055] In the drawings, reference numbers may be reused to identify similar and / or identical elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0056] Before describing the shroud and other features of the present disclosure, the problem that the present disclosure solves will be described with reference to Figures 1 and 2. The solution to the problem provided by the shroud and other features will then be described in detail with reference to Figures 3A-14.

[0057] tool FIG. 1 shows a plan view of an example of a substrate processing system (also referred to as a tool) 100. The tool includes four stations 102-1, 102-2, 102-3, and 102-4 (collectively, stations 102). Although only four stations 102 are shown for illustrative purposes, the tool 100 may include N stations, where N is an integer equal to or greater than 1. Each station 102 includes a well in which a pedestal is disposed (both shown in FIG. 2). A top plate 104 and a purge plate 106 are disposed above the stations 102. The top plate 104 and the purge plate 106 include openings concentric with the wells of the stations 102. A top plate ring (collectively, top plate ring 108, shown at 108-1, 108-2, 108-3, and 108-4) is disposed around each opening. A showerhead (shown in FIG. 2) is positioned through an opening above each station 102 to supply process and purge gases into the stations 102 .

[0058] During processing, a substrate such as a semiconductor wafer (shown in FIG. 2) is placed on the pedestal, and process and purge gases are supplied through the showerhead to process the substrate. Purge gas (e.g., an inert gas) is supplied through holes drilled in the purge plate 106 to purge process gases and process by-products that escape through the top plate ring 108. A spindle 110 is centrally located with respect to the station 102 as shown. Robot arms 112-1, 112-2, 112-3, and 112-4 (collectively, robot arm 112) are attached to the periphery of the spindle 110. The spindle 110 moves the robot arm 112 laterally in a plane parallel to the top plate 104 and the purge plate 106. An end effector (not shown) moves the substrate from a load lock (not shown) into the station 102-1. A spindle 110 and robot arm 112 move substrates between stations 102 through a transfer port (not shown) located near the top end of stations 102 .

[0059] Station FIG. 2 shows an example of a cross-sectional view of one of the stations 102 without the shroud and liner of the present disclosure. The station 102 includes a well 130. The well 130 is cylindrical and hollow. For example, the well 130 has the shape of an open cylindrical vessel or container. The station 102 includes a pedestal 150 and a showerhead 152. The pedestal 150 is disposed within the well 130. The pedestal 150 includes a base 160 and a stem 162. The stem 162 extends vertically downward from a central region of the base 160. The base 160 and the stem 162 are cylindrical. The base 160 has a larger diameter than the stem 162. An edge ring 164 is disposed around the base 160. A substrate 166 is disposed on an upper surface of the base 160. The edge ring 164 surrounds the substrate 166. The inner diameter (ID) of the edge ring and the outer diameter (OD) of the base 160 are larger than the diameter of the substrate 166. During processing, the base 160 is heated and process and purge gases are supplied by the showerhead 152 during each process cycle.

[0060] The showerhead 152 includes an edge ring 155. The edge ring 155 is disposed in a recess at the bottom of the showerhead 152 around the OD of the showerhead 152. The edge ring 155 surrounds the substrate-facing surface (faceplate) of the showerhead 152. The edge ring 155 and the showerhead 152 have the same OD. The edge ring 155 is thicker than the depth of the recess and extends slightly below the faceplate of the showerhead 152. As a result, the faceplate of the showerhead 152 is flush (horizontal) with the top edge of the top plate ring 108, but the bottom of the edge ring 155 extends slightly below the top edge of the top plate ring 108. The edge ring 155 is disposed above the edge ring 164.

[0061] A heat shield 168 is coupled to the underside of the base 160 using fasteners 170-1, 170-2 (collectively, fasteners 170). The heat shield 168 extends radially from the top end of the stem 162 to the OD of the base 160. An actuator 172 is attached to the bottom end of the stem 162 of the pedestal 150. The actuator 172 moves the pedestal 150 vertically to adjust the gap between the substrate 166 and the showerhead 152. The heat shield 168 moves with the pedestal 150. The gap between the edge rings 155 and 174 is maintained as the pedestal 150 moves vertically relative to the showerhead 152.

[0062] Lift pin assemblies 174 (designated 174-1 and 174-2, with 174-3 not visible in the depicted views, collectively lift pin assemblies 174) are disposed within wells 130 of station 102. Each lift pin assembly 174 includes a lift pin 176 (designated 176-1 and 176-2, with 176-3 not visible in the depicted views, collectively lift pin 176). Each lift pin 176 is attached to a respective base 178 (designated 178-1 and 178-2, with 178-3 not visible in the depicted views, collectively base 178). Base 178 acts as a counterweight to stationary each lift pin 176. The distal ends of the lift pins 176 pass through the fasteners 170 of the heat shield 168 , pass through the base 160 of the pedestal 150 , and extend to the upper surface of the base 160 .

[0063] The actuator 172 lowers the pedestal 150 to deposit the substrate 166 into the station. As the pedestal 150 is lowered, the lift pins 176 protrude from the top surface of the base 160. The robot arm 112 (shown in FIG. 1 ) deposits the substrate 166 onto the lift pins 176 in the station 102 and retracts. The substrate 166 is now on the lift pins 176. The actuator 172 then lifts the pedestal 150. The lift pins 176, which are stationary and held by a counterweight of the base 178, are recessed into the base 160. The substrate 166 is now on the top surface of the base 160 and is ready to be processed using process gases provided by the showerhead 152.

[0064] [Problem to be solved by the invention] Process gases and process by-products typically flow through the top plate ring 108 (e.g., through the gap between the edge rings 155 and 164) toward adjacent stations 102 and into the wells 130 of the stations 102. The flow of these outflowing process gases (e.g., unreacted process gases) and process by-products (collectively referred to as contaminants) is indicated by solid arrows. The flow of contaminants from one station 102 to another station 102 is referred to as crosstalk between the stations 102. The purge gas provided through the purge plate 106 is insufficient to keep the contaminants from contaminating the adjacent stations 102 and the wells 130 of the stations 102. In addition to the purge gas provided by the showerhead 152, a purge gas (e.g., an inert gas) is also provided into the wells 130 from an assembly coupled to the lower end of the stem portion 162 of the pedestal 150 to dilute the contaminants in the wells 130. For example, the assembly may include a bellows (not shown) disposed around the actuator 172. The flow of purge gas is indicated by dashed arrows. The diluted contaminants are exhausted through a pair of exhaust ports (shown in FIG. 5A ) in well 130 and into the exhaust system (not shown) of tool 100. Throughout this disclosure, for simplicity, the flow of contaminants and purge gas is shown on only one side of station 102. It is understood that similar flows occur all around station 102.

[0065] Currently, crosstalk between stations 102 is reduced by providing purge gas that is fed through the purge plate 106. The purge gas fed through the purge plate 106 forms a curtain of purge gas around the showerhead 152. The curtain of purge gas acts as a shield between stations 102. Pressure differences between stations 102 and / or between stations 102 and the cover area (the space between the two stations 102, including the top plate 104 and the purge plate 106) may affect the function of the curtain gas. In addition, process by-products that diffuse into the wells 130 require more purge time to purge the by-products that diffused out of the wells 130 through the exhaust port. This may affect the throughput of the tool 100. As a result, contaminants may deposit on the cover area, on the transfer ports, and in the wells 130 of the stations 102. For some reactants used in some processes, repeated cleaning of the stations 102 is insufficient to clean the contaminants. Additionally, some of the contaminants create nucleation sites on the interior and other surfaces of the tool 100. The nucleation sites allow further accumulation of the contamination, causing the formation of an undesirable contamination layer on the tool surface.

[0066] [Summary of the Invention] To address the above-mentioned issues, the present disclosure provides a shroud around the pedestal 150 and a wall liner around the sidewalls and bottom of the well 130 to reduce crosstalk between stations 102 and to reduce contamination within the well 130. The present disclosure further provides a reduction vessel disposed within the well 130 to reduce the volume of the well 130. This reduces contaminants within the well 130 and reduces the time to purge contaminants from the well 130 to the exhaust system during a purge cycle of the process. The shroud, wall liner, and reduction vessel are described in more detail below with reference to Figures 3A-14.

[0067] Briefly, the shroud is a hollow cylindrical element attached to the base 160 of the pedestal 150. The shroud surrounds the base 160 of the pedestal 150 and extends vertically downward from the base 160 of the pedestal 150 towards the well 130. The shroud moves with the pedestal 150. The shroud may comprise a metallic material (e.g., alloy) or a non-metallic material (e.g., ceramic material) depending on the temperature requirements of the process performed in the station 102. The shroud creates a microvolume around the showerhead 152 relative to the top plate ring 108 due to a small gap maintained between the shroud and the top plate ring 108. The microvolume and the purge gas provided from the showerhead 152 during the purge cycle of the process reduce the flow of process by-products into the cover area and can be diverted to the well 130 instead. The process by-products diverted to the well 130 are diluted by the purge gas provided by the showerhead 152 and the lower end of the stem portion 162 of the pedestal 150. The volume of the well 130 can be reduced by inserting a vacuum vessel into the well 130, as described below. The purge gas provided by the lower end of the stem portion 162 flows around the vacuum vessel. The process by-products diluted in the well 130 are exhausted through an exhaust port in the well 130 to the exhaust system of the tool. The process by-products are restricted from entering the cover area by the minute volume, so that the process by-products cannot contaminate the cover area and the transfer ports of the stations 102. Furthermore, only a minimal amount of contaminants flowing from the top plate ring 108 can flow to adjacent stations 102, minimizing crosstalk between the stations 102.

[0068] Additionally, as described in more detail below, a vertical wall liner extends along the ID of the sidewall of the well 130 from the bottom of the well to the top of the well. The top of the wall liner surrounds the bottom of the shroud even as the shroud moves vertically with the pedestal 150. A small gap is maintained between the ID of the top of the wall liner and the OD of the bottom of the shroud, creating a microvolume therebetween. A pressure differential exists between the curtain of purge gas provided from the purge plate 106 outside the well 130 and the purge gas provided into the well 130 from the bottom of the stem portion 162 of the pedestal 150. Due to the pressure differential and the microvolume between the wall liner and the shroud, process by-products diluted within the well 130 do not drain through the gap between the wall liner and the shroud and contaminate the adjacent station 102. Additionally, contamination within the well 130 is significantly reduced by filling the space available within the well 130 with a reducing container, which reduces the volume of the well 130. The reduced well volume also reduces the purge time to remove contaminants from the well 130 during the process purge cycle, improving throughput.

[0069] Thus, the shroud around the pedestal 150 acts as a physical barrier for process by-products, diverting them to the well 130 of the station 102 and limiting the flow of process by-products to the cover area and adjacent stations 102. The shroud creates a microvolume in the circumferential direction around the showerhead 152 relative to the top plate ring 108. The gap between the shroud and the top plate ring 108 is empirically optimized to limit the flow of process by-products through the gap. The gap can accommodate the manufacturing and assembly tolerances of the shroud and the top plate ring 108. The shroud also creates a microvolume in the radial direction with the wall liner of the well 130, preventing backflow of process by-products from the well 130 to the cover area and adjacent stations 102. Instead, the diverted process by-products occupy a volume in the well 130 that is reduced by the reduction vessel. The reduction vessel is placed at the bottom of the well and surrounded by the wall liner, with the height of the reduction vessel being less than the height of the wall liner. The reduced volume not only prevents contamination within the well 130, but also reduces the purge time required to purge contaminants from the reduced volume of the well 130. A heat shield 168 insulates the reduced volume and prevents heat from the base 160 of the pedestal 150 from heating the reduced volume. These and other features of the present disclosure are described in more detail below.

[0070] [Disclosure Structure] The remainder of this disclosure is organized as follows: Various cross-sectional views of the station, including the shroud and various liners and associated gas flows, are shown and described with reference to Figures 3A-5B; The station's well, exhaust port, and port liners for the exhaust port are shown and described with reference to Figures 5A and 5B; Different types of bottom liners for the station's wells are shown and described with reference to Figures 6-9; Wall liners for the station's wells are shown and described with reference to Figures 9A-11; A reduction vessel is shown and described with reference to Figures 12A-13; The shroud is shown and described with reference to Figure 14.

[0071] Station with shroud and liner 3A-5B show examples of stations with shrouds and various liners. The bottom liners for the wells of the stations can be annular or disc-shaped. An annular bottom liner is used with a reduction vessel as shown and described with reference to FIG. 3A. A disc-shaped bottom liner can be used with or without a reduction vessel. An example of a station using a disc-shaped bottom liner without a reduction vessel is shown and described with reference to FIG. 4A. Gas flows for the two configurations (with and without a reduction vessel and corresponding bottom liners) are shown and described with reference to FIGS. 3B and 4B. To simplify the description of the gas flows, the lift pin assemblies shown in FIGS. 3A and 4A have been omitted from FIGS. 3B and 4B.

[0072] 3A shows a cross-sectional view of a station (such as station 102 shown in FIGS. 1 and 2) that includes a shroud for pedestal 150 and a liner for well 130, including an annular bottom liner for well 130. Elements shown and described with reference to FIG. 2 will not be described again for the sake of brevity.

[0073] The station 102 comprises a shroud 200. The shroud 200 is a hollow, skirt-like, cylindrical element attached to the base 160 of the pedestal 150. The shroud 200 surrounds (is around) the base 160. The shroud 200 extends vertically downward from the circumference (OD) of the base 160 towards the well 130. The shroud 200 extends below the heat shield 168. The shroud 200 and the pedestal 150 are coaxial. The height of the shroud 200 is greater than the height of the base 160. The height of the shroud 200 is the sum of the height of the base 160 and the height of at least a portion of the stem portion 162. The height of the shroud 200 is less than the height of the pedestal 150. That is, the height of the shroud 200 is less than the sum of the height of the base 160 and the height of the stem portion 162. The shroud 200 is attached to the base 160 via an edge ring 164 as follows.

[0074] The edge ring 164 is disposed around the circumference (OD) of the base 160. The edge ring 164 comprises a cylindrical portion 202, a first flange 204, and a second flange 206. The cylindrical portion 202 surrounds the OD of the base 160. The first flange 204 extends radially inward from an upper end of the cylindrical portion 202. The second flange 206 extends radially outward from a lower end of the cylindrical portion 202.

[0075] The top surface of the base 160 includes a recess 208. The recess 208 extends radially inward from the circumference (OD) of the top surface of the base 160. The first flange 204 resides in the recess 208. The depth (width) of the recess 208 matches the length of the first flange 204. The cylindrical portion 202 is in direct contact with the OD of the base 160. The ID of the cylindrical portion 202 matches the OD of the base 160.

[0076] A plurality of pins 210 are used to couple the shroud 200 to the base 160. Each pin 210 includes a head 212 and a shaft 214 extending from the head 212. The heads 212 of the pins 210 rest on the second flange 206 of the edge ring 164. The shafts 214 of the pins 210 are inserted into corresponding holes 216 located along the top edge of the shroud 200. The holes 216 extend through corresponding attachment locations 217 that project radially inward from the ID of the shroud 200 (see FIG. 14 ).

[0077] The head 212 of the pin 210 is larger in diameter than the shaft 214 of the pin 210. The length of the head 212 is such that when the shaft 214 is inserted into a hole 216 in the shroud 200, a small gap 218 is maintained between the ID of the shroud 200 and the OD (end) of the second flange 206. The use of the small gap 218 is described below with reference to FIG. 3B.

[0078] The shroud 200, attachment locations 217, and holes 216 are shown in more detail in Figure 14. When the shroud 200 is attached to the edge ring 164, a small gap 219 is maintained between the upper end of the shroud 200 and the top plate ring 108. The shroud 200 creates a microvolume around the showerhead 152 opposite the top plate ring 108 due to the small gap 219 maintained between the shroud 200 and the top plate ring 108. The use of the small gap 219 is described below with reference to Figure 3B.

[0079] An annular bottom liner 220 (hereinafter bottom liner 220) is disposed on a top surface 222 of the bottom of the well 130. Although the bottom liner 220 is shown as a single piece throughout this disclosure, the bottom liner 220 may comprise multiple arcuate segments that can be joined to form the annular bottom liner 220. The OD of the bottom liner 220 aligns with the ID of the well 130 (i.e., the ID of the inner sidewall 224 of the well 130). The ID of the annular bottom liner 220 aligns with the OD of a reduction vessel 230 disposed within the well 130. The annular bottom liner 220 is shown and described in detail below with reference to FIG. 6.

[0080] The reduction vessel 230 is shown and described in detail below with reference to Figures 12A-13. Briefly, the reduction vessel 230 is generally cylindrical, although other shapes may be used. The reduction vessel 230 has an outer sidewall 234, an inner sidewall 236, and an upper surface 238. The upper surface 238 extends between the outer sidewall 234 and the inner sidewall 236. The reduction vessel 230 is open at the bottom (i.e., unenclosed). The reduction vessel 230 is hollow. The reduction vessel 230 rests on the upper surface 222 of the bottom of the well 130. The inner sidewall 236 of the reduction vessel 230 surrounds the stem portion 162 of the seat 150. The reduction vessel 230 generally fills more than half of the volume of the well 130, reducing the volume of the well 130.

[0081] The ID of the reduction vessel 230 (i.e., the OD of the inner sidewall 236) is greater than the OD of the stem portion 162 of the pedestal 150. As a result, a small gap 233 is maintained between the ID of the reduction vessel 230 (i.e., the OD of the inner sidewall 236) and the OD of the stem portion 162 of the pedestal 150. Gas flow through the small gap 233 is shown and described below with reference to FIG. 3B.

[0082] The OD of the reducing vessel 230 (i.e., the OD of the outer sidewall 234) is aligned with the ID of the bottom liner 220. The length (height) of the inner sidewall 236 of the reducing vessel 230 is slightly shorter than the length (height) of the outer sidewall 234 of the reducing vessel 230. Thus, when the reducing vessel 230 is placed on the upper surface 222 of the bottom of the well 130, the lower end of the outer sidewall 234 contacts the upper surface 222 of the bottom of the well 130, but the lower end of the inner sidewall 236 does not contact the upper surface 222 of the bottom of the well 130. As a result, an opening 231 exists between the lower end of the inner sidewall 236 and the upper surface 222 of the bottom of the well 130. Gas flow through the opening 231 is shown and described below with reference to FIG. 3B.

[0083] The height of the reduction vessel 230 is less than the depth (height) of the well 130. The height of the reduction vessel 230 is the distance between the top surface 222 of the bottom of the well 130 and the top surface 238 of the reduction vessel 230. The height of the reduction vessel 230 is also the length (height) of the outer sidewall 234 of the reduction vessel 230. The height of the reduction vessel 230 is less than the height of the wall liner (described below). The outer sidewall 234 of the reduction vessel 230 includes a plurality of stepped (concave) portions 232 that extend radially inward from the OD of the outer sidewall 234 of the reduction vessel 230. The base 178 of the lift pin assembly 174 resides in the recess 232.

[0084] Two semi-circular wall liners are disposed along the inner sidewall 224 of the well 130. The wall liners are shown and described in detail with reference to Figures 9A-11. Although two wall liners are shown and described for purposes of illustration throughout this disclosure, it will be understood that a single cylindrical wall liner may be used instead. Alternatively, a wall liner comprising multiple arcuate elements may be used to completely cover the inner sidewall 220 of the well 130.

[0085] In the views shown in Figures 3A-4B, only one of the two semicircular wall liners is visible and is designated 240. The wall liner 240 extends vertically upward from the top surface 222 of the bottom of the well 130 along the inner sidewall 224 of the well 130 to the top end 226 of the well 130. The wall liner 240 covers the entire inner sidewall 224 of the well 130. The OD of the wall liner 240 aligns with the ID of the well 130 (i.e., the ID of the inner sidewall 224 of the well 130). The lower end of the wall liner 240 is on the upper surface of the bottom liner 220 near the OD of the bottom liner 220. Alternatively, although not shown, the lower end of the wall liner 240 may extend to and be on the top surface 222 of the bottom of the well 130, and the OD of the bottom liner 220 may align with the ID of the wall liner 240.

[0086] The upper end of the wall liner 240 extends radially outwardly to form a flange 239. The flange 239 is at the upper end 226 of the well 130. Additionally, the upper end of the wall liner 240 includes a plurality of protrusions 242 (only one protrusion 242 is visible in the figures). The protrusions 242 extend radially outwardly from the upper end of the wall liner 240. The protrusions 242 extend further than the flange 239. The protrusions 242 are at the upper end 226 of the well 130. The protrusions 242 cover respective access openings (see Figures 5A and 9A-11) along the upper end 226 of the well 130. The flange 239 and the protrusions 242 are shown and described in further detail with reference to Figures 9A-11.

[0087] The height of the wall liner 240 is approximately the same as the height (depth) of the well 130. The height of the wall liner 240 is greater than the height of the reduction vessel 230. The height of the shroud 200 is less than the heights of the wall liner 240, the well 130, and the reduction vessel 230. The ID of the wall liner 240 is slightly greater than the OD of the shroud 200. As a result, a small gap 221 is maintained between the OD of the shroud 200 and the ID of the wall liner 240. Gas flow through the small gap 221 is shown and described below with reference to FIG. 3B. Further features of the wall liner 240 are shown and described below with reference to FIGS. 9A-11.

[0088] The wall liner 240 is substantially perpendicular to the bottom liner 220. The wall liner 240 is substantially parallel to the shroud 200. The bottom liner 220 is also substantially perpendicular to the shroud 200. The shroud 200, bottom liner 220, reduction vessel 230, wall liner 240, well 130, pedestal 150, and showerhead 152 are concentric. This term substantially takes into account any slight tilt of the pedestal 150 relative to the vertical axis and any slight curvature of the upper surface 222 of the bottom of the well 130.

[0089] FIG. 3B illustrates the gas flows of FIG. 3A. The flow of purge gas is illustrated using dotted arrows. The flow of process gases and process by-products is illustrated using solid arrows. For ease of illustration, the gas flows are shown on only one side of the cross-sectional view of station 102. It is understood that similar gas flows occur throughout station 102. To clearly illustrate the gas flows, lift pin assembly 174 shown in FIG. 3A has been omitted from FIG. 3B, but is assumed to be present in FIG. 3B.

[0090] As mentioned above, the microvolume is created by the small gap 219 maintained between the shroud 200 and the top plate ring 108. Purge gas is provided from the showerhead 152 during the purge cycle of the process, as shown at 153. The microvolume and purge gas prevent process by-products from entering the cover area, as shown at 250, and divert them through the small gap 218 to the well 130, as shown at 252.

[0091] In addition, as described above, purge gas is also supplied from the lower end of stem portion 162 of pedestal 150. As shown, the purge gas flows through small gap 233 and around the periphery of reduction vessel 230. As shown, the purge gas also flows into reduction vessel 230 through opening 231, thereby preventing contamination of the interior of reduction vessel 230 by process by-products.

[0092] The process by-products diverted into the well 130 are diluted by the purge gas provided from the showerhead 152 and from the lower end of the stem portion 162 of the pedestal 150. Additionally, the pressure differential between the inside and outside of the well 130 keeps the diluted process by-products in the well 130 from escaping through the small gap 221 maintained between the OD of the shroud 200 and the ID of the wall liner 240. Instead, the diluted process by-products in the well 130 are exhausted through an exhaust port (shown in FIG. 5A ) in the well 130 and into the tool's exhaust system.

[0093] Process by-products are restricted from entering the cover area by the microvolume created by the small gap 219 between the shroud 200 and the top plate ring 108, so they cannot contaminate the cover area and the transfer ports of the stations 102 (shown in FIG. 5A). Additionally, crosstalk between stations 102 is minimized because minimal contaminants flow out of the top plate ring 108 and into adjacent stations 102. Crosstalk is further reduced by the microvolume created by the small gap 221 between the OD of the shroud 200 and the ID of the wall liner 240. Additionally, contamination within the wells 130 is prevented by reducing the volume of the wells 130 using the reduction vessel 230. The reduced well volume also reduces the purge time to remove contaminants from the wells 130 during the purge cycle of the process, improving process throughput.

[0094] Thus, the shroud 200 around the pedestal 150 acts as a physical barrier for processing by-products, diverting the flow of process by-products to the wells 130 of the stations 102 and limiting the flow of process by-products to the cover area and adjacent stations 102. The shroud 200 creates a microvolume around the showerhead 152 relative to the top plate ring 108. A small gap 219 between the shroud 200 and the top plate ring 108 is empirically optimized to limit the flow of process by-products through the small gap 219. The small gap 219 can accommodate manufacturing and assembly tolerances of the shroud 200 and the top plate ring 108.

[0095] The shroud 200 also creates a radial microvolume with the wall liner 240 of the well 130, which prevents backflow of process by-products from the well 130 through the small gap 221 between the shroud 200 and the wall liner 240 into the covered area and adjacent stations 102. Instead, the diverted process by-products occupy a volume within the well 130 that is reduced by the reduction vessel 230, as described above. Thus, the reduction vessel 230 not only prevents contamination within the well 130, but also reduces the purge time required to purge contaminants from the reduced volume of the well 130. The heat shield 168 shields the reduction vessel 230 and prevents heat from the base 160 of the pedestal 150 from heating the reduction vessel 230.

[0096] FIG. 4A shows a cross-sectional view of a station (e.g., station 102 shown in FIGS. 1 and 2) with a shroud 200, a wall liner 240, and a disk-shaped bottom liner for the well 130. The only difference between FIG. 4A and FIG. 3A is that FIG. 3A uses an annular bottom liner 220 and a reducing vessel 230, while FIG. 4A uses a disk-shaped bottom liner and does not use a reducing vessel 230 (although the disk-shaped bottom liner may use a reducing vessel 230). Therefore, only the differences between FIG. 3A and FIG. 4A due to the different bottom liner and the absence of a reducing vessel will be described. All other elements shown and described with reference to FIG. 2 and FIG. 3A will not be described again for the sake of brevity.

[0097] In Figure 4A, a disk-shaped bottom liner 260 (hereinafter bottom liner 260) is disposed on the top surface 222 of the bottom of the well 130. Although the bottom liner 260 is shown as a single piece throughout this disclosure, the bottom liner 260 may comprise multiple segments that can be joined to form the disk-shaped bottom liner 260. The disk-shaped bottom liner 260 is shown and described in detail below with reference to Figures 7A and 7B.

[0098] Briefly, the bottom liner 260 extends radially from about the OD of the stem portion 162 of the pedestal 150 to the ID of the well 130 (i.e., the ID of the inner sidewall 224 of the well 130). The OD of the bottom liner 260 aligns with the ID of the well 130 (i.e., the ID of the inner sidewall 224 of the well 130). The ID of the bottom liner 260 is slightly larger than the OD of the stem portion 162 of the pedestal 150. An opening 235 exists between the ID of the bottom liner 260 and the top surface 222 of the bottom of the well 130. Gas flow through the opening 235 is shown and described below with reference to FIG. 4B. The base 178 of the lift pin assembly 174 is on the top surface of the bottom liner 260.

[0099] The lower end of the wall liner 240 is at the top surface of the bottom liner 260 near the OD of the bottom liner 260. Alternatively, although not shown, the lower end of the wall liner 240 may extend up to and be at the top surface 222 of the bottom of the well 130, with the OD of the bottom liner 260 aligned with the ID of the wall liner 240.

[0100] The wall liner 240 is perpendicular to the bottom liner 260. The bottom liner 260 is also perpendicular to the shroud 200. The shroud 200, the bottom liner 260, the wall liner 240, the well 130, the pedestal 150, and the showerhead 152 are concentric.

[0101] FIG. 4B illustrates the gas flows of FIG. 4A. As in FIG. 3B, the flow of purge gas is illustrated using dotted arrows, and the flow of process gas and process by-products is illustrated using solid arrows. For ease of illustration, the gas flows are shown on only one side of the cross-sectional view of the station 102. It is understood that similar gas flows occur throughout the station 102. To clearly illustrate the gas flows, the lift pin assembly 174 shown in FIG. 4A is omitted from FIG. 4B, but is assumed to be present in FIG. 4B. Only the differences in gas flows resulting from the absence of a reduction vessel in FIG. 4B are described. All other descriptions of FIG. 3B that apply to FIG. 4B will not be repeated for the sake of brevity. If a reduction vessel 230 is used with a disk-shaped bottom liner 260, the gas flows in FIG. 4B will be similar to those shown and described with reference to FIG. 3B.

[0102] Purge gas is provided from the lower end of stem portion 162 of pedestal 150 and flows through opening 235 and through the volume of well 130 as shown. This prevents contamination of the interior of well 130 with process by-products. Process by-products are diverted to well 130 as described above with reference to FIG. 3B. Process by-products diverted to well 130 are diluted and exhausted through exhaust ports in well 130 (shown in FIG. 5A) to the tool's exhaust system as described above with reference to FIG. 3B. The remaining description of FIG. 3B applies equally to FIG. 4B except for reference to the reducing vessel and will not be repeated for brevity.

[0103] Station Well and Port Liners 5A-5B show the wells, exhaust ports, and port liners for the exhaust ports of the station. FIG. 5A shows the well 130 without the wall liner 240, the reduction vessel 230, and the bottom liners 220, 260. The well 130 has two exhaust ports located diametrically opposite each other. Only one exhaust port is visible and shown in the view shown in FIG. 5A. The port liners are shown and described in detail with reference to FIG. 5B. Please refer to both FIG. 5A and FIG. 5B when reading the description of the port liners.

[0104] In Figure 5A, an exhaust port 270 is located in the sidewall 224 of the well 130. The exhaust port 270 is located adjacent to (along) the top surface 222 of the bottom of the well 130. A port liner 272 is inserted into the exhaust port 270. The port liner 272 is shown and described in further detail with reference to Figure 5B. The port liner 272 covers (i.e., covers) the exhaust port 270. The port liner 272 prevents contamination of the exhaust port 270 from process by-products exhausting through the exhaust port 270 into the tool's exhaust system, as described above with reference to Figures 3B and 4B.

[0105] The well 130 further includes access openings 292-1, 292-2, and 292-3 (collectively, access openings 292) along the circumference of the upper end 226 of the sidewall 224 of the well 130. The lift pin assembly 174 is accessible through the access openings 292. As shown and described with reference to Figures 9A-11, the wall liner 240 includes a protrusion 242 at the upper end of the wall liner 240 that covers the access openings 292. The protrusion 242 covers the access openings 292 to prevent contaminants from entering the well 130 through the access openings 292.

[0106] The well 130 further includes an opening 290 in the center of the bottom upper surface 222 of the well 130. The stem portion 162 of the pedestal 150 fits into the opening 290. The well 130 also includes holes 294 (only one hole 294 is visible in the illustration) in the bottom upper surface 222 of the well 130. A corresponding locating pin on the bottom surface of the bottom liner 260 (shown and described with reference to Figures 7A and 7B) fits into the hole 294.

[0107] Figure 5B shows the port liner 272 in more detail. Some of the reference numerals described below are shown in Figure 5A. The port liner 272 includes a first portion 274 that fits within and around the periphery of the exhaust port 270. The exhaust port 270 and first portion 274 are generally rectangular. A first end 280 of the first portion 274 extends radially outward from the sidewall 224 of the well 130 and laterally through the exhaust port 270.

[0108] The port liner 272 includes a second portion 276 that extends vertically from the second end 282 of the first portion 274 along the ID of the sidewall 224 of the well 130. The second portion 276 also extends laterally from the second end 282 of the first portion 274 along the ID of the sidewall 224 of the well 130. The top end 275 of the second portion 276, the second end 282 of the first portion 274, the top surface 277 of the first portion 274, and the ID of the sidewall 224 of the well 130 form a slot 278 (shown in FIG. 5A). The bottom of the wall liner 240 includes a notch (see FIGS. 10A and 10B) that fits into the slot 278, as described in more detail below with reference to FIGS. 9A-11.

[0109] Bottom Liner 6 shows the annular bottom liner 220. The ID and OD of the annular bottom liner 220 have already been described above with reference to FIG. 3A. The bottom liner 220 includes a recess 284 extending radially outward from the OD of the bottom liner 220. The bottom of the wall liner 240 resides in the recess 284. The thickness of the wall liner 240 (i.e., the distance between the ID and OD of the wall liner 240) matches the width of the recess 284.

[0110] Additionally, bottom liner 220 includes two notches 286 and 288. When bottom liner 220 is placed on top surface 222 of the bottom of well 130, notches 286 and 288 mate with bottom end 279 of second portion 276 of port liner 272 (see FIGS. 5A and 5B). Bottom end 279 of second portion 276 of port liner 272 fits into notches 286 and 288.

[0111] 7A and 7B show the disk-shaped bottom liner 260 in further detail. FIG. 7A shows a top view of the bottom liner 260. FIG. 7B shows a bottom view of the bottom liner 260. The ID and OD of the annular bottom liner 260 have already been described above with reference to FIG. 4A. In FIG. 7A and 7B, the bottom liner 260 is shown to include features that can be used with the reducing vessel 230. If the reducing vessel 230 is not used with the bottom liner 260, the features of the bottom liner 220 related to the reducing vessel 230 can be omitted.

[0112] 7A, the bottom liner 260 includes a recess 300 extending radially outward from the OD of the bottom liner 260. The bottom of the wall liner 240 resides in the recess 300. The thickness of the wall liner 240 (i.e., the distance between the ID and OD of the wall liner 240) matches the width of the recess 300.

[0113] The top surface of the bottom liner 260 includes a number of positioning pins 302-1, 302-2, 302-3, and 302-4 (collectively, positioning pins 302) for aligning the wall liner 240 between the positioning pins 302 and the ID of the sidewall 224 of the well 130 and fitting the wall liner 240 into the recess 300.

[0114] The upper surface of the bottom liner 260 includes a number of locating pins 304-1, 304-2, and 304-3 (collectively, locating pins 304) for aligning the outer sidewall 234 of the reduction vessel 230 with the upper surface 222 of the bottom of the well 130.

[0115] The top surface of the bottom liner 260 includes a number of notches or directional tabs 306-1, 306-2, and 306-3 (collectively, directional tabs 306) for aligning and orienting the top surface of the bottom liner 260 with the reduced vessel 230. As shown and described below with reference to Figures 12A-13, the reduced vessel 230 includes corresponding protrusions that fit into the directional tabs 306. The directional tabs 306 ensure that the multiple stepped (concave) portions 232 of the reduced vessel 230 are properly oriented to receive the bases 178 of the lift pin assemblies 174 in the recesses 232. Circular markings 308-1, 308-2, 308-3 (collectively, circular markings 308) on the top surface of the bottom liner 260 indicate the location of the bases 178 of the lift pin assemblies 174. If the reduction vessel 230 is placed directly on the bottom upper surface 222 of the well 130, similar locating pins, orientation tabs, and markings may be provided on the bottom upper surface 222 of the well 130.

[0116] Additionally, bottom liner 260 includes two notches 310 and 312. When bottom liner 260 is placed on the top surface 222 of the bottom of well 130, notches 310 and 312 mate with bottom end 279 of second portion 276 of port liner 272. Bottom end 279 of second portion 276 of port liner 272 fits into notches 286 and 288.

[0117] The bottom liner 260 further includes an opening 314 in the center of the bottom liner 260 that defines the ID of the bottom liner 260. The stem portion 162 of the seat 150 passes through the opening 314. The opening 314 mates with an opening 290 in the top surface 222 of the bottom of the well 130. The stem portion 162 of the seat 150 passes through the opening 314 and into the opening 290 in the top surface 222 of the bottom of the well 130.

[0118] In Figure 7B, the bottom surface of bottom liner 260 includes a number of locating pins 316-1, 316-2, and 316-3 (collectively, locating pins 316) for aligning bottom liner 260 with bottom top surface 222 of well 130. Locating pins 316 fit into holes 294 in bottom top surface 222 of well 130 (see Figure 5A).

[0119] 8 shows a well 130 with a bottom liner 260 and a port liner 272, but without a reduction vessel 230 and a wall liner 240. The bottom liner 260 fits into the bottom top surface 222 of the well 130 using locating pins 316 on the bottom surface of the bottom liner 260 and corresponding holes 294 in the bottom top surface 222 of the well 130 (all shown with reference to FIGS. 5A-7B and described above). The notches 310 and 312 in the bottom liner 260 mate with the bottom end 279 of the second portion 276 of the port liner 272 (all shown with reference to FIGS. 5A-7B and described above). The opening 314 in the center of the bottom liner 260 mates with the opening 290 in the bottom top surface 222 of the well 130 (all shown with reference to FIGS. 5A-7B and described above).

[0120] Wall Liner 9A-10B show the wall liner 240. As described above with reference to FIG. 3A, the wall liner 240 comprises two semicircular wall liners disposed along the inner sidewall 224 of the well 130. FIGS. 9A and 9B show two perspective views (front and back) of a first semicircular portion 240-1 of the wall liner 240. FIGS. 10A and 10B show two perspective views (front and back) of a second semicircular portion 240-2 of the wall liner 240. The first and second semicircular portions 240-1 and 240-2 are collectively referred to as the wall liner 240 or wall liners 240.

[0121] 9A and 9B, a first semicircular portion 240-1 (hereafter, first portion 240-1) of the wall liner 240 is shown. The first portion 240-1 includes two protrusions 242-1 and 242-2 (one protrusion 242 is shown in FIG. 3A) that cover corresponding access openings 292 in the upper end 226 of the well 130. The protrusions 242-1 and 242-2 are semicircular and align with the access openings 292-1 and 292-2, respectively. The protrusions 242-1 and 242-2 extend radially outward from the upper end of the first portion 240-1.

[0122] The ID and OD of the wall liner 240 have already been described above with reference to FIG. 3A. The upper end of the first portion 240-1 extends radially outwardly along the circumference of the first portion 240-1 to form a flange 239-1. The projections 242-1 and 242-2 further extend from the flange 239-1. The first portion 240-1 further comprises recesses 322-1 and 322-2 (collectively, recesses 322) at opposite ends of the first portion 240-1. The recesses 322 extend along the height of the first portion 240-1 at opposite ends of the first portion 240-1. For example, the recesses 322 may be located along the ID of the first portion 240-1.

[0123] 10A and 10B, the second semicircular portion 240-2 (hereafter, second portion 240-2) of the wall liner 240 is shown. The second portion 240-2 includes a third protrusion 242-3 that covers a corresponding access opening 292 in the upper end 226 of the well 130. The protrusion 242-3 is similar to the protrusions 242-1 and 242-2 (i.e., the protrusion 242-3 is semicircular and aligns with the third access opening 292-3). The protrusion 242-3 extends radially outward from the upper end of the second portion 240-2.

[0124] The upper end of the second portion 240-2 also extends radially outwardly along the circumference of the second portion 240-2 to form a flange 239-2. The flange 239-2 is identical to the flange 239-1. A protrusion 242-3 further extends from the flange 239-2. The protrusions 242-1, 242-2, and 242-3 are collectively referred to as the protrusions 242. The flanges 239-1 and 239-2 are collectively referred to as the flange 239.

[0125] The second portion 240-2 further includes recesses 324-1 and 324-2 (collectively, recesses 324) at opposite ends of the second portion 240-2. The recesses 324 extend along the height of the second portion 240-2 at opposite ends of the second portion 240-2. For example, the recesses 324 may be located along the OD of the second portion 240-2.

[0126] The first and second portions 240-1 and 240-2 mate with each other to form the cylindrical wall liner 240 by recesses 322 and 324 located along the ID and OD of the first and second portions 240-1 and 240-2. Specifically, the recesses 322 and 324 mate with each other and the flanges 239-1 and 239-2 mate with each other (see FIG. 11). The second portion 240-2 further includes two notches 330-1, 330-2 (collectively, notches 330) along the bottom end of the second portion 240-2 at either end of the second portion 240-2. As shown in FIG. 11, the notches 330 mate with the slots 278 of the port liner 272 (shown in FIG. 5A).

[0127] 11 shows well 130 with bottom liner 260, port liner 272, and wall liner 240, but without reduction vessel 230. Bottom liner 260 fits onto top surface 222 of the bottom of well 130, as described above with reference to FIG. 8. Wall liner 240 is further seated within well 130 along interior sidewall 224 of well 130, as described above with reference to FIGS. 3A and 9A-10B. First and second portions 240-1 and 240-2 fit together at 332. Notch 330 is not visible because it fits into slot 278 in port liner 272.

[0128] Reduced containers 12A and 12B show the reduced vessel 230 in further detail. FIG. 12A shows a top perspective view of the reduced vessel 230. FIG. 12B shows a bottom perspective view of the reduced vessel 230. As already described with reference to FIG. 3A, the reduced vessel 230 is generally cylindrical with a stepped (concave) portion 232 extending radially inward from the OD of the outer sidewall 234 of the reduced vessel 230. The base 178 of the lift pin assembly 174 is in the recess 232 (e.g., at a location such as that shown at 237). Other features such as the OD, ID, and height of the reduced vessel 230 have already been described above with reference to FIG. 3A. For the sake of brevity, the description will not be repeated.

[0129] The reduction vessel 230 also includes an opening 334 defined by the inner sidewall 236 of the reduction vessel 230. The opening 334 mates with the central opening 314 in the bottom liner 260, which in turn mates with the central opening 290 in the bottom upper surface 222 of the well 130. The stem portion 162 of the seat 150 passes through the openings 334 and 314 and into the central opening 290 in the bottom upper surface 222 of the well 130.

[0130] In FIG. 12B, the inner sidewall 236 and the stepped (concave) portion 232 are more clearly visible. As can be seen, the inner sidewall 236 is cylindrical and concentric with the outer sidewall 234. As already described with reference to FIG. 3A, the height of the inner sidewall 236 is less than the height of the outer sidewall 234. The bottom of the reduced vessel is open (i.e., unenclosed). A number of protrusions 336-1, 336-2, and 336-3 (collectively, protrusions 336) are disposed at the bottom end (edge) of the outer sidewall 234. The protrusions 336 fit into directional tabs 306 of the bottom liner 260, as shown and described with reference to FIGS. 7A and 7B. If the bottom liner 220 is used instead of the bottom liner 260, the protrusions 336 fit into similar directional tabs 306 provided on the upper surface 222 of the bottom of the well 130.

[0131] It should be noted that the shape of the reduction vessel 230 may vary. For example, the outer sidewall 234 may taper radially inward from the bottom of the outer sidewall 234 to the top surface 238 of the reduction vessel 230 toward the inner sidewall 236. Additionally, while the bottom of the reduction vessel 230 is shown and described as being open (i.e., not closed), in some examples the bottom of the reduction vessel 230 may be closed using a disk-shaped plate having the diameter of the outer sidewall 234, similar to the bottom liner 260, to form a closed reduction vessel. Many other variations in the shape of the reduction vessel 230 are possible, so long as the reduction vessel 230 reduces the volume of the well 130, includes a location for the base 178 of the lift pin assembly 174, and allows gas to flow around the reduction vessel, similar to that described with reference to FIG. 3B.

[0132] FIG. 13 shows a well 130 with a bottom liner 220 or 260, a port liner 272, a wall liner 240, and a reduction vessel 230. The port liner 272 (not visible) is installed within the exhaust port 270 as shown and described above with reference to FIGS. 5A and 5B. The bottom liner 220 or 260 (not visible) is fitted to the top surface 222 of the bottom of the well 130 as shown and described above with reference to FIGS. 3A and 4A and 6-8. The wall liner 240 is installed within the well 130 along the inner sidewall 224 of the well 130 as shown and described above with reference to FIGS. 3A and 9A-11. All three projections 242-1, 242-2, and 242-3 of the wall liner 240 are shown which fit into corresponding access openings 292. Also shown are connection points 232 for both the first and second portions 240-1 and 240-2 of the wall liner 240. The reduction vessel 230 is installed within the well 130 as shown and described above with reference to Figures 3A and 12A-13.

[0133] Shroud FIG. 14 shows a perspective view of the shroud 200. The OD, ID, and height of the shroud 200 have already been described above with reference to FIG. 3A. For the sake of brevity, the description will not be repeated. Shown are a number of attachment locations 217 including holes 216 (both shown in FIG. 3A). The holes 216 are drilled at each attachment location 217. The attachment locations 217 project radially inward from the ID of the shroud 200. Note that the number of attachment locations 217 and holes 216 may differ (fewer or more) than shown. Additionally, the spacing of the attachment locations 217 may differ from that shown.

[0134] The bottom liners 220 and 260, wall liner 240, and reduction vessel 230 may be constructed from a metallic material, such as aluminum or an alloy. The bottom liners 220 and 260, wall liner 240, and reduction vessel 230 may include a coating of a corrosion-resistant material, such as electroless nickel plating. The shroud 200 and pins 210 may be constructed from a ceramic material, such as aluminum nitride. The lift pins 176 may be constructed from a ceramic material, such as sapphire.

[0135] It should be noted that the use of the shroud 200, wall liner 240, reduction vessel 230, bottom liner 220 or 260, and port liner 270 all reduces contamination and crosstalk as described above. However, some processes may use different combinations of the shroud 200 and one or more of the wall liner 240, reduction vessel 230, bottom liner 220 or 260, and port liner 270 depending on the acceptable levels of contamination and crosstalk. For example, some processes may omit one or more of the wall liner 240, reduction vessel 230, bottom liner 220 or 260, and port liner 270 depending on the acceptable levels of contamination and crosstalk.

[0136] The above description is merely exemplary in nature and is not intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be embodied in various forms. Thus, although the disclosure includes specific examples, the true scope of the disclosure should not be so limited, since other modifications will become apparent upon review of the drawings, specification, and claims that follow.

[0137] It should be understood that one or more steps in a method may be performed in different orders (or simultaneously) without changing the principles of the present disclosure. Moreover, although each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure can be implemented in and / or combined with the features of any other embodiment, even if the combination is not specified. In other words, the embodiments described herein are not mutually exclusive, and substituting one or more embodiments for one another still falls within the scope of the present disclosure.

[0138] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using a variety of terms, including "connected," "engaged," "coupled," "adjacent," "next to," "on top of," "above," "below," and "disposed." When a relationship between a first element and a second element is described in the above disclosure, unless specified as "direct," the relationship may be a direct relationship where there are no other intervening elements between the first element and the second element, but there may also be an indirect relationship where there are one or more intervening elements (spatially or functionally) between the first element and the second element. As used herein, the phrase at least one of A, B, and C should be interpreted as meaning the logic (A OR B OR C) using a non-exclusive logical OR, and not as meaning "at least one of A, at least one of B, and at least one of C."

[0139] Exemplary systems may include, but are not limited to, a plasma etch chamber or module, a deposition chamber or module, a spin rinse chamber or module, a metal plating chamber or module, a cleaning chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a tracking chamber or module, and any other semiconductor processing system related to or usable in the fabrication and / or manufacturing of semiconductor wafers.

Claims

1. 1. A station of a substrate processing system, comprising: a pedestal disposed within the well of the station, the pedestal comprising a base for supporting a substrate and a stem extending from the base into the well of the station; a shroud coupled to the base of the pedestal, the shroud surrounding the base and extending along the stem into the well of the station; A station comprising:

2. 2. The station of claim 1, The station further comprising a liner lining an inner sidewall of the well of the station.

3. 2. The station of claim 1, The station further comprises a liner covering a pedestal-facing surface of a bottom of the well of the station.

4. 2. The station of claim 1, The station further comprising a hollow object disposed within the well of the station, the hollow object being smaller in size than the well of the station.

5. 2. The station of claim 1, a first liner lining an inner sidewall of the well of the station; a second liner covering the base-facing surface of the bottom of the well; a hollow object disposed in the well, the height of the well and the first liner being greater than the height of the hollow object; The station is further equipped with:

6. 6. A station according to claim 5, The well includes an exhaust port, the station further includes a third liner covering the exhaust port, and the first and second liners mate with the third liner.

7. 6. A station according to claim 5, The second liner is annular, with an outer edge contacting the first liner and an inner edge contacting the hollow object.

8. 6. A station according to claim 5, A station wherein a gap is maintained between the first liner and the shroud.

9. 6. A station according to claim 5, The shroud, the first and second liners, the hollow body, the well, and the pedestal are concentric.

10. 6. A station according to claim 5, The hollow object has an outer sidewall with a smaller diameter than the first liner and an inner sidewall with a larger diameter than the stem portion of the base, and the first liner is taller than the hollow object.

11. 11. A station according to claim 10, The second liner and the well each have a central opening, and the stem portion of the base passes through the inner sidewall of the hollow object and through the openings of the second liner and the well.

12. 11. A station according to claim 10, The well is An exhaust port; Gas inlet and Equipped with The gas flows around the hollow object and exits the well through the exhaust port.

13. 13. A station according to claim 12, comprising: The station further comprises a third liner covering the exhaust port and mating with the first and second liners.

14. 2. The station of claim 1, The station further comprises an edge ring disposed around the base of the pedestal, the shroud being attached to the edge ring with a gap maintained between the shroud and the edge ring.

15. 15. A station according to claim 14, The well is a first liner covering an inner sidewall of the well; a second liner covering the base-facing surface of the bottom of the well; a hollow object disposed in the well, wherein the height of the well and the first liner is greater than the height of the hollow object; An exhaust port; Entrance and Equipped with A station wherein gas enters the well through the gap and the inlet, flows around the hollow object, and exits the well through the exhaust port.

16. 16. A station according to claim 15, The station further comprises a third liner covering the exhaust port and mating with the first and second liners.

17. 2. The station of claim 1, The well includes an exhaust port, and the station includes: a first liner covering an inner sidewall of the well; a second liner covering the base-facing surface of the bottom of the well; a third liner covering the exhaust port and mating with the first liner and the second liner; The station is further equipped with:

18. 18. A station according to claim 17, a hollow object disposed within the well and having dimensions smaller than the well; the height of the first liner is greater than the height of the hollow object; The second liner is annular, with an outer edge contacting the first liner and an inner edge contacting the hollow object.

19. 20. A station according to claim 18, comprising: an edge ring disposed around the base of the pedestal; the shroud is attached to the edge ring with a gap maintained between the shroud and the edge ring, the well comprises an inlet; A station wherein gas enters the well through the gap and the inlet, flows around the hollow object, and exits the well through the exhaust port.

20. 2. The station of claim 1, an object comprising an outer sidewall, an inner sidewall, and a first surface connecting first ends of the outer sidewall and the inner sidewall; the object is placed on a second surface of the bottom of the well, the second surface being opposite the first surface; A station, wherein the height of the object is less than the depth of the well in the station.

21. 21. A station according to claim 20, a first liner covering an inner sidewall of the well; a second liner covering the second surface of the bottom of the well; and Furthermore, the first liner is higher than the object; The second liner is annular, with an outer edge contacting the first liner and an inner edge contacting the outer sidewall of the object.

22. 21. A station according to claim 20, The inner sidewall of the object is shorter than the outer sidewall of the object and does not contact the second surface of the bottom of the well.

23. The station of claim 21, The station further comprising a plurality of lift pin assemblies supporting the substrate, the object comprising recesses into which the lift pin assemblies are placed.

24. 24. A station according to claim 23, comprising: the well includes a plurality of openings along an edge of the well facing the pedestal for accessing the lift pin assembly, and the first liner includes protrusions extending radially outward to cover the openings.

25. 21. A station according to claim 20, The station further comprises a heat shield coupled to an end of the base opposite the well, the shroud surrounding the heat shield.

26. 2. The station of claim 1, The well includes an exhaust port, and the station includes: a first liner covering the exhaust port; a second liner covering the inner sidewall of the well and mating with the first liner; The station is further equipped with:

27. 27. A station according to claim 26, comprising: The station further comprises a third liner covering the pedestal-facing surface of the bottom of the well and mating with the first and second liners.

28. 28. A station according to claim 27, comprising: The station further comprises a hollow object disposed within the well, wherein the well and the second liner are greater in height than the hollow object.

29. 29. A station according to claim 28, comprising: The third liner is annular, with an outer edge contacting the second liner and an inner edge contacting the hollow object.

30. 29. A station according to claim 28, comprising: an edge ring disposed around the base of the pedestal; the shroud is attached to the edge ring with a gap maintained between the shroud and the edge ring, the well comprises an inlet; A station wherein gas enters the well through the gap and the inlet, flows around the hollow object, and exits the well through the exhaust port.

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