Pedestal support assembly for chemical vapor deposition chamber

Abstract

An apparatus for rotating a substrate within a deposition chamber is described. The substrate is rotated using a substrate support assembly having a shaft and a base coupled to a top of the shaft. The base and the shaft are coupled together using an engagement feature. The engagement feature includes a plurality of teeth or protrusions on the coupling portion of the shaft that interlock with grooves provided on the bottom of the base. A lift pin assembly is further coupled to the shaft and configured to raise and lower the substrate from the base.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to substrate support apparatus for use in processing chambers. More particularly, embodiments of the present disclosure relate to substrate support shafts and corresponding pedestals for use within deposition chambers for semiconductor processing. Background Art

[0002] Processing semiconductor substrates is used in a variety of applications, including the manufacture of integrated devices and microdevices. A method of processing a substrate includes depositing a material, such as a semiconductor material or a conductive material, on an upper surface of a substrate. For example, epitaxial deposition is a deposition process that deposits films of various materials on a substrate surface in a processing chamber. The epitaxial deposition process is capable of producing high quality films on substrates having a crystalline structure. The epitaxial deposition process is performed in a processing chamber under various processing conditions, such as temperature, pressure, and precursor flow rates. The quality and consistency of the epitaxial layer depends on precise temperature and flow control inside the chamber.

[0003] During deposition of a film on a substrate, the substrate is typically rotated about the substrate's axis of symmetry. The speed and uniformity of the rotation further affects the deposition of the film on the substrate surface. Tilt and sway are introduced into the motion of the susceptor by various components within the substrate support assembly. Suspension sway and tilt reduce deposition uniformity on the substrate and increase the difficulty of performing the process and maintaining the susceptor.

[0004] Thus, there is a need for improved apparatus that reduces susceptor rocking and tilting during substrate processing. Summary of the invention

[0005] The present disclosure generally relates to a substrate support assembly configured for semiconductor processing. In one embodiment, the substrate support assembly includes a base, a shaft, and a shaft coupling portion. The base includes a substrate supporting surface, a coupling surface, and a cogged indent in the coupling surface. The shaft includes a first distal end and a second distal end opposite the first distal end. The shaft coupling portion is coupled to the first distal end of the shaft and disposed in the cogged indent.

[0006] In another embodiment, a pedestal is described. The pedestal is configured for semiconductor processing. The pedestal includes a substrate support surface, a coupling surface opposite the substrate support surface, and an engagement recess disposed in the coupling surface. The engagement recess further includes a central opening and a plurality of wings extending outward from the central opening across the coupling surface.

[0007] In another embodiment, a shaft is described. The shaft is configured for semiconductor processing. The shaft includes a first distal end, a second distal end opposite the first distal end, and a shaft coupling portion coupled to the first distal end of the shaft. The shaft coupling portion includes a coupling contact surface and a plurality of projections extending outwardly from a central portion of the coupling contact surface so that the coupling contact surfaces engage. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to be able to understand in detail the manner in which the above-mentioned features of the present disclosure are used, a more specific description of the present disclosure briefly summarized above may be made with reference to embodiments, some of which are shown in the accompanying drawings. However, it will be noted that the accompanying drawings only illustrate exemplary embodiments and are therefore not to be considered as limiting the scope thereof, and other equally effective embodiments may be allowed.

[0009] Figure 1 is a schematic cross-sectional view of a deposition chamber according to one embodiment of the present disclosure.

[0010] Figure 2 is a schematic isometric view of a substrate support assembly according to one embodiment of the present disclosure.

[0011] Figure 3A is a schematic cross-sectional view of a shaft member according to one embodiment of the present disclosure.

[0012] Figure 3B is a schematic plan view of a shaft coupling portion according to one embodiment of the present disclosure.

[0013] Figure 4 is a schematic bottom view of a base according to one embodiment of the present disclosure.

[0014] FIG. 5A to FIG. 5D is a schematic diagram of a portion of a shaft motion coupling according to an embodiment of the present disclosure.

[0015] Fig. 6A and Figure 6B is a schematic isometric view of a substrate support assembly according to an embodiment of the present disclosure.

[0016] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. DETAILED DESCRIPTION

[0017] The present disclosure relates to a substrate support assembly including a pedestal and a shaft. The pedestal and shaft are coupled together using a meshing configuration. The use of a meshing configuration within the described pedestal and shaft configuration reduces swaying of the pedestal during substrate processing (such as during epitaxial deposition processing), and rotation of the substrate support assembly. Swaying of the pedestal and a substrate disposed on the pedestal during processing may result in asymmetric and / or non-uniform film thickness growth.

[0018] The meshing configuration described herein reduces swing by providing a simple and secure coupling of a rotating shaft and a base / base support mechanism. Each of the base, shaft, and the lifting pin to be set through the shaft is one or a combination of graphite, quartz, thermoplastic, or metal. The base is a material formed of high thermal conductivity, such as graphite. The shaft is formed of an optically transparent material to achieve uniform heating of the substrate. The use of a single shaft and the optical transparency of the components of the substrate support assembly further reduces the shielding caused by the shaft and / or the lifting pin. The meshing interface between the shaft and the base can be further described as a spline interface or a gear interface. The use of the meshing interface further achieves stress distribution along multiple surfaces within the interface between the shaft and the base. The reduced stress reduces the possibility of deformation and cracking or peeling at the interface. The shape of the meshing interface reduces the stress at a single point. For example, the use of a curved contact surface on each extension / protrusion of the meshing interface helps to distribute the load along the curved surface rather than a single point or a group of points.

[0019] The interface at the bottom of the shaft to the rotating assembly further achieves reduced warping and damage to the shaft by using a plurality of pins disposed between the shaft and the rotating assembly. The plurality of pins are disposed within grooves of the shaft and held in place between the shaft and the rotating assembly coupling. The shape, configuration, and material of the pins further reduce stress on the shaft and enable rotation of the shaft and, therefore, the base.

[0020] Figure 1 1 is a schematic illustration of a type of deposition chamber 100. The deposition chamber 100 is used to grow epitaxial films on a substrate, such as substrate 102. The deposition chamber 100 creates a cross flow of precursors across a top surface 150 of the substrate 102.

[0021] The deposition chamber 100 includes an upper body 156, a lower body 148 disposed below the upper body 156, and a flow module 112 disposed between the upper body 156 and the lower body 148. The upper body 156, the flow module 112, and the lower body 148 form a chamber body. A substrate support assembly 105, an upper dome 108, a lower dome 110, a plurality of upper lamps 141, and a plurality of lower lamps 143 are disposed within the chamber body. As shown, a controller 120 communicates with the deposition chamber 100 and is used to control processes such as those described herein. The substrate support assembly 105 includes a base 106 and a shaft 118 coupled to the substrate support 106. The base 106 is disposed between the upper dome 108 and the lower dome 110. A plurality of upper lamps 141 are disposed between the upper dome 108 and the cover 154. The cover 154 includes a plurality of sensors 153 disposed therein for measuring the temperature within the deposition chamber 100. A plurality of lower lamps 143 are disposed between the lower arch structure 110 and a floor 152. The plurality of lower lamps 143 form a lower lamp assembly 145.

[0022] A processing volume 136 is formed between the upper arch 108 and the lower arch 110. The processing volume 136 has a pedestal 106 disposed therein. The pedestal 106 includes a top surface on which the substrate 102 is disposed. The shaft member is connected to the motion assembly 121. The motion assembly 121 includes one or more actuators and / or adjustment devices that provide movement and / or adjustment of the substrate support assembly 105. The movement is first applied to the shaft member 118 and the shaft member 118 transmits the movement to the pedestal 106 within the processing volume 136. The motion assembly 121 includes a rotary actuator 122 that rotates the shaft member 118 and the pedestal 106 about the longitudinal axis A of the deposition chamber 100. The motion assembly 121 further includes a vertical actuator 124 to raise and lower the substrate support assembly 105 in the z direction. The motion assembly 121 includes a tilt adjustment device 126 for adjusting the planar orientation of the base 106 and a lateral adjustment device 128 for adjusting the position of the shaft 118 and the base 106 side by side within the processing volume 136.

[0023] The pedestal 106 may include lift pin holes 107 disposed therein. The lift pin holes 107 are sized to accommodate lift pins 132 for lifting the substrate 103 from the pedestal 106 before or after performing a deposition process. The lift pins 132 may rest on lift pin stops 134 when the pedestal 106 is lowered from the processing position to the transfer position.

[0024] The flow module 112 includes a plurality of process gas inlets 114, a plurality of purge gas inlets 164, and one or more exhaust gas outlets 116. The plurality of process gas inlets 114 and the plurality of purge gas inlets 164 are disposed on a side of the flow module 112 opposite to the one or more exhaust gas outlets 116. One or more flow guides 146 are disposed below the plurality of process gas inlets 114 and the one or more exhaust gas outlets 116. The flow guide 146 is disposed above the purge gas inlet 164. A liner 163 is disposed on an inner surface of the flow module 112 and protects the flow module 112 from reactive gases used during a deposition process. The process gas inlets 114 and the purge gas inlets 164 are positioned to flow gases parallel to a top surface 150 of a substrate 102 disposed within the processing volume 136. The process gas inlet 114 is fluidly connected to a process gas source 151. The purge gas inlet 164 is fluidly connected to a purge gas source 162. The one or more exhaust gas outlets 116 are fluidly connected to an exhaust pump 157. Each of the process gas source 151 and the purge gas source 162 may be configured to supply one or more precursors or process gases into the processing volume 136 .

[0025] Figure 2 , Figure 3A and Figure 3B , Figure 4 , FIG. 5A to FIG. 5D ,and Fig. 6A and Figure 6B Each of the figures shows a full or partial view of the substrate support assembly 105. The substrate support assembly 105 includes a base 106 coupled at the top distal end of the shaft 118. The coupling of the base 106 and the shaft 118 is performed at the shaft coupling. The shaft coupling is a meshing feature and extends into a corresponding meshing groove in the base 106. The meshing feature includes a plurality of engagement portions extending from a central member and is configured to distribute torque loads applied to the shaft and the base by the rotating base and the substrate disposed on the top of the base. The meshing feature includes a plurality of teeth or protrusions that are intended to interlock with gaps, wings, or openings in the meshing groove. Using a single shaft and meshing feature to couple the base 106 and the shaft 118 achieves a reduction in the amount of wobble of the base 106 during rotation. The meshing feature reduces or eliminates the use of multiple arms and corresponding fingers to hold the base 106. The mating features and shafts may further be formed from quartz material to reduce shadowing.

[0026] Figure 21 is a schematic isometric view of the substrate support assembly 105. The substrate support assembly includes a base 106 and a shaft 118. The base 106 and the shaft 118 are coupled together at a mating interface. The mating interface includes a base coupling portion 212 within the coupling surface 204 of the base 106 and a shaft coupling portion 202 coupled to the first distal end 206 of the shaft 118. The second distal end 316 ( Figure 3A ) is coupled to the shaft motion coupling 208 of the shaft motion assembly 210.

[0027] The base coupling portion 212 and the shaft coupling portion 202 are matched together so that the shaft coupling portion 202 is inserted into the engagement groove 402 ( Figure 4 ). The engagement groove 402 and the shaft coupling portion 202 cooperate together so that the engagement groove 402 has a shape similar to (e.g., corresponding to) the shape of the shaft coupling portion 202. In some embodiments, the engagement groove 402 has a shape opposite to the shaft coupling portion 202, so that a groove having the same shape and size as the shaft coupling portion 202 is formed. Thus, the base coupling portion 212 can be considered to be a female portion of the coupling, while the shaft coupling portion 202 is considered to be a male portion of the coupling.

[0028] The coupling surface 204 is a bottom surface of the pedestal 106 such that the coupling surface 204 is disposed opposite a substrate receiving surface or substrate supporting surface. The substrate supporting surface is a top surface of the pedestal 106 on which the substrate 102 is disposed. The pedestal coupling portion 212 is a portion of the coupling surface 204 such that the pedestal coupling portion 212 extends from a center of the coupling surface 204 away from the top surface of the pedestal 106 and the coupling surface 204.

[0029] The second distal end 316 of the shaft 118 is coupled to the shaft motion coupling 208. The second distal end 316 is provided on the end of the shaft 118 opposite the first distal end 206. The shaft motion coupling 208 is the upper portion of the shaft motion assembly 210. The shaft motion assembly 210 is part of the rotation assembly and can be a part of the motion assembly 121, such as Figure 1 The shaft motion assembly 210 includes one or more motors or actuators and is configured to effect rotation of the shaft motion coupling 208 and thus the shaft 118 and the base 106.

[0030] Figure 3A1 is a schematic cross-sectional view of the shaft 118. The shaft 118 includes a shaft body 318 having a first distal end 206 and a second distal end 316. The first distal end 206 is coupled to the shaft coupling portion 202. The second distal end 316 is configured to be inserted into the shaft motion coupling 208. The shaft coupling portion 202 includes a body having a coupling contact surface 312, a shaft insertion surface 314 disposed opposite to the coupling contact surface 312, and an outer surface 310 disposed between the coupling contact surface 312 and the shaft insertion surface 314. The coupling contact surface 312 further includes a plurality of features 406 ( Figure 4 ) of multiple features 302, which are arranged in the base coupling portion 212.

[0031] The shaft body 318 is a cylindrical body. The shaft body 318 is formed of an optically transparent material such as quartz. Using an optically transparent material as the shaft body 318 reduces the shadowing effect of the shaft body 318 on the base 106. The second distal end 316 of the shaft body 318 has a smaller diameter than the first distal end 206, so that the outer surface 320 of the shaft body 318 has a larger diameter at the first distal end 206 of the shaft body 318 than the diameter at the second distal end 316 of the shaft body 318.

[0032] The top surface 306 of the shaft 118 is configured to be disposed within the shaft receiving opening 308 of the shaft coupling portion 202. The shaft receiving opening 308 is configured to have a first distal end 320 of the shaft disposed therein such that the top surface 306 of the shaft 118 supports the weight of the shaft coupling portion 202 and any base 106 or substrate 102 disposed thereon. The shaft receiving opening 308 is disposed through the shaft insertion surface 314 and the shaft 118 is inserted into the shaft receiving opening 308. The shaft receiving opening 308 and the top surface 306 of the shaft 118 can be fused, bonded, welded, or brazed together. In some embodiments, the shaft receiving opening 308 and the top surface 306 are removed such that the shaft 118 is formed from a single piece of material.

[0033] The coupling contact surface 312 is disposed on the side of the shaft coupling portion 202 opposite the shaft 118. The coupling contact surface 312 is configured to be inserted into the engagement groove 402, thereby serving as a mating feature. The base 106 is configured to rest on the coupling contact surface 312 to facilitate mating and / or engagement therebetween. The coupling contact surface 312 includes a plurality of features 302 and a center alignment opening 304. The plurality of features 302 are a plurality of grooves extending into the coupling contact surface 312. The plurality of features 302 are configured to receive a plurality of features 406 ( Figure 4). The plurality of features 406 of the engagement groove 402 are a first plurality of features, and the plurality of features 302 of the coupling contact surface 312 are a second plurality of features. The first plurality of features extend into (eg, engage and / or interface with) the first plurality of features.

[0034] The plurality of features 302 assist in aligning the coupling contact surface 312 relative to the engagement groove 402 and reduce variation and movement of the engagement groove 402 relative to the coupling contact surface 312. The center alignment opening 304 is configured to receive a protrusion from the center of the engagement groove 402. The center alignment opening 304 is configured to centrally align the shaft coupling portion 202 with the engagement groove 402.

[0035] Figure 3B 4 is a schematic plan view of the shaft coupling portion 202. As shown, the shaft coupling portion 202 includes a plurality of protrusions 322 extending outwardly from a central portion of the shaft coupling portion 202 and a coupling contact surface 312. The plurality of protrusions 322 are teeth or protrusions extending outwardly and configured to interlock with corresponding portions of the engagement groove 402. Each of the plurality of protrusions 322 includes a curved outer surface 324. The curved outer surface 324 forms a side surface of each of the protrusions 322, so that the curved outer surface 324 is configured to be compressed when the shaft 118 is rotated to cause the base 106 to rotate. In some embodiments, the curved outer surface 324 of each of the protrusions 322 forms a semicircle. The outermost surface of each of the plurality of protrusions 322 is the outer surface 310 of the shaft coupling portion 202.

[0036] One feature 302 of the plurality of features 302 is disposed in each of the protrusions 322 such that each of the protrusions 322 includes a feature 302 disposed along its centerline. In some embodiments, there are fewer features 302 such that there is less than one feature 302 for each protrusion 322 such that the ratio of features 302 to protrusions 322 is from about 1:3 to about 1:1, such as from about 1:2.5 to about 1:1.5, such as about 1:2.

[0037] By utilizing multiple protrusions 322, stress applied to any one portion of the shaft coupling portion 202 during rotation is reduced. However, since an increase in the number of protrusions 322 results in a decrease in the structural integrity of each of the protrusions 322 and makes the manufacture of the shaft coupling portion 202 more difficult, the number of protrusions 322 may be limited. In some embodiments, there are 3 or more protrusions 322, such as 5 to 12 protrusions 322, such as 6 to 10 protrusions 322, such as 7 to 9 protrusions, such as 8 protrusions.

[0038] Figure 41 is a schematic bottom view of the base 106. An engagement groove 402 is disposed within the base coupling portion 212. The engagement groove 402 includes a central opening 405 and a plurality of wings 410 extending outwardly from the central opening 405 across the base coupling portion 212. The plurality of wings 410 are extensions of the central opening 405 and substantially match the shape of the shaft coupling portion 202 and the plurality of protrusions 322 to the shape of the engagement groove 402. The engagement groove further includes a center alignment protrusion 404. The center alignment protrusion 404 is configured to fit into the center alignment opening 304 of the shaft coupling portion 202. Each of the plurality of wings 410 of the engagement groove 402 includes a side wall 408. The side wall 408 of each wing 410 of the engagement groove 402 has a curved portion, such that at least a portion of each wing 410 has a curved side wall 408.

[0039] Each of the side walls 408 is configured to be compressed when the shaft 118 is rotated to cause the base 106 to rotate. In some embodiments, the side walls 408 of each of the wings 410 form a semicircle. Each of the side walls 408 is curved to distribute the compressive force applied by the protrusion 322 of the shaft coupling portion 202 over a larger surface and reduce deformation and possible damage to the base 106.

[0040] One feature 406 of the plurality of features 406 is disposed in each of the wings 410 such that each of the wings 410 includes a feature 406 disposed along its centerline. In some embodiments, there are fewer features 406 such that there is less than one feature 406 for each wing 410 such that the ratio of features 306 to wings 410 is about 1:3 to about 1:1, such as about 1:2.5 to about 1:1.5, such as about 1:2. Each of the features 406 of the engagement groove 402 is a pin extending from the bottom surface of the engagement groove 402 and extending into one of the features 302 of the shaft coupling portion 202.

[0041] In some alternative embodiments, the features 302 are pins and the features 406 are recesses configured to receive the pins, with the pins forming the features 302 of the shaft coupling portion 202 .

[0042] By utilizing a plurality of wings 410, stress applied to any one portion of the engagement groove 402 during rotation is reduced. However, since an increase in the number of wings 410 results in a decrease in the structural integrity of each of the wings 410 and makes the manufacturing of the engagement groove 402 more difficult, the number of wings 410 may be limited. In some embodiments, there are 3 or more wings 410, such as 5 to 12 wings 410, such as 6 to 10 wings 410, such as 7 to 9 wings 410, such as 8 wings 410.

[0043] The susceptor 106 is formed of a highly thermally conductive material to achieve uniform heat distribution across the susceptor 106. The susceptor 106 may thus be a graphite or silicon carbide material. In some embodiments, the susceptor 106 is a quartz material to make the susceptor 106 optically transparent to light emitted by the lamp within the deposition chamber 100.

[0044] FIG. 5A to FIG. 5D is a schematic diagram of a portion of the shaft motion coupling 208 . Figure 5A is a schematic isometric view of a shaft motion coupling 208 in which the shaft 118 is disposed. The shaft motion coupling 208 includes a flange 502 into which the second distal end 316 of the shaft 118 is inserted. The flange 502 has a lower shaft 504 that can be disposed within the shaft motion assembly 502. A plurality of pin rollers 508 are disposed between a groove 506 in the second distal end 316 of the shaft 118 and the flange 502. The plurality of pin rollers 508 help to hold the shaft 118 in place relative to the flange 502.

[0045] Figure 5B is a schematic side view of the shaft motion coupling 208 in which the shaft 118 is disposed. Figure 5B As shown, each of the grooves 506 is disposed within the second distal end 316 of the shaft 118 such that the grooves 506 extend inwardly into the shaft 118 .

[0046] Figure 5C is a schematic cross-sectional view of the shaft motion coupling 208 in which the shaft 118 is disposed. The pin roller 508 has a cylindrical sidewall and extends into a radial appendage 514 of the central opening 512 of the flange 502. The central opening 512 of the flange 502 is an opening configured to receive the second distal end 316 of the shaft 118 within the flange 502. The inner surface of the central opening 512 can be aligned with the inner side of one of the grooves 506.

[0047] Figure 5D 208 is a schematic plan view of the shaft motion coupling 208. Figure 5D As shown, each of the radial appendages 514 is an extension of the central opening 512 and extends outward. The central opening 512 includes a side wall 510. The side wall 510 is annular, and the radial appendages 514 protrude from the circular shape forming the side wall 510. The pin roller 508 is disposed in each of the radial appendages 514, so that each of the pin rollers 508 is disposed between the side wall 510 and the shaft member 118. The shape of the radial appendages 514 and the groove 506 is configured to hold the pin roller 508 in place and the pin roller 508 is configured to couple the movement of the flange 502 to the shaft member 118.

[0048] In some embodiments, there are two or more pin rollers 508 and two or more radial appendages 514, such as three or more pin rollers 508 and three or more radial appendages 514. Using multiple pin rollers 508 and radial appendages 514 helps distribute the load on any one surface of the shaft 118 and prevents the shaft 118 from breaking or chipping.

[0049] Each of the pin rollers 508 is formed of a thermoplastic, metal, graphite, or silicon carbide material. The pin rollers 508 are configured to withstand the stress of applying rotation to the shaft 118 without breaking or deforming significantly. The flange 502 is formed of a metal or metal alloy, such as one or more of nickel, chromium, molybdenum, and niobium. The flange 502 is configured to have reduced deformation while applying a large amount of force to the pin rollers 508 and the shaft 118.

[0050] Fig. 6A and Figure 6B is a schematic isometric view of substrate support assemblies 600a, 600b. Fig. 6A and Figure 6B The substrate support assemblies 600a, 600b further illustrate various lift pin arrangements that may be used to raise and lower a substrate from the susceptor 106, such that a plurality of lift pins 604 are sent through the susceptor 106 to raise and lower the substrate. The lift pins 604 within each of the substrate support assemblies 600a, 600b are formed of a quartz material.

[0051] Fig. 6A A substrate support assembly 600a including a lift pin assembly is shown. The lift pin assembly forms a sleeve 608 disposed around the shaft 118. The sleeve 608 extends from the shaft motion coupling 608 to an upper portion of the shaft 118. The sleeve 608 is a hollow cylinder surrounding the shaft 118. A plurality of lift pin support arms 606 extend outwardly from the sleeve 608. A lift pin 604 is disposed on the top of each of the lift pin support arms 606 at a distal end 602 opposite the sleeve 608. The lift pin support arms 606 may be one of a quartz material, a silicon carbide material, or a graphite material.

[0052] In the embodiment described herein, the lift pin support arms 606 are disposed at an angle orthogonal to the lift pins 604 themselves. There is a single lift pin 604 extending from each of the lift pin support arms 606. The single lift pin 604 extends upwardly from the lift pin support arms 606 away from the sleeve 608. There are three or more lift pin support arms 606 and lift pins 604, such as four or more lift pin support arms 606 and lift pins 604.

[0053] Figure 6BA substrate support assembly 600b is shown that utilizes a linear motion device 610 disposed on a side of the substrate support assembly 105. At least a portion of the linear motion device 610 of the substrate support assembly 600b may be disposed outside of the processing volume 136. The linear motion device 610 includes a linear actuator 612 and a Y-shaped lift pin support member 614 extending into the processing volume 136 toward the shaft 118. The lift pin support member 614 includes a central neck 620 at a distal end of the lift pin support member 614 away from the linear actuator 612. The central neck 620 is a ring disposed around the shaft 118. Two arms 616 extend from the central neck 620 and away from the lift pin support member 614. The two arms 616 are of similar length and include a lift pin 604 disposed at a distal end thereof away from the central neck 620 and extending upward through the base 106. A third lift pin 604 is disposed on and extends upward from the lift pin support member 614. The third lift pin 604 is disposed between the connection to the linear actuator 612 and the center neck 620 .

[0054] The substrate support assemblies 600a, 600b described herein are at least partially achieved by using a single shaft member 118 and a mating interface between the substrate 106 and the shaft member 118. The substrate support assemblies 600a, 600b are configured to have reduced shadowing on the pedestal.

[0055] Embodiments of the substrate support assembly 105 described herein are configured to have reduced shadowing and reduced swaying compared to other substrate support assemblies 105. Reduced shadowing and reduced swaying are achieved using cooperating features, such as mating features, to couple the shaft 118 and the pedestal 106. As the pedestal 106 and shaft 118 are heated, thermal expansion of the mating features can further reduce movement of the pedestal and a substrate disposed thereon.

[0056] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the following claims.

Claims

1. A substrate support assembly configured for use in semiconductor processing, comprising: Base, including: a substrate support surface; a coupling surface; and an engagement groove in the coupling surface; and Shaft, including: First distal end; as well as a second distal end, the second distal end being opposite to the first distal end; as well as A shaft coupling portion is coupled to the first distal end of the shaft and is disposed in the engagement groove.

2. The substrate support assembly of claim 1, wherein the engagement recess comprises a central opening and a plurality of wings extending outwardly from the central opening across the coupling surface. 3 . The substrate support assembly of claim 2 , wherein each of the plurality of wings is an extension of the central opening and three or more wings extend radially outward from the central opening.

4. The substrate support assembly of claim 3, wherein the central opening has a circular cross-section.

5. The substrate support assembly of claim 1, wherein the engagement recess further comprises a plurality of first features.

6. The substrate support assembly of claim 5, wherein the shaft coupling portion further comprises a plurality of second features on a coupling surface of the shaft coupling portion.

7. The substrate support assembly of claim 6, wherein the first feature is a plurality of pins extending from the engagement recess and the plurality of second features are a plurality of recesses extending into the coupling surface and the plurality of pins extend into the plurality of recesses.

8. The substrate support assembly of claim 1, further comprising a shaft motion coupling coupled to the second distal end of the shaft.

9. The substrate support assembly of claim 8, wherein the shaft motion coupling comprises a central opening, a plurality of radial appendages extending outwardly from the central opening, and the second distal end of the shaft comprises a plurality of grooves disposed therein.

10. The substrate support assembly of claim 9, wherein the plurality of radial appendages are extensions of the central opening and a pin is disposed between each of the radial appendages and each of the grooves.

11. A susceptor configured for semiconductor processing, comprising: a substrate support surface; a coupling surface, the coupling surface opposite the substrate supporting surface; as well as an engagement groove disposed in the coupling surface and further comprising: Center opening; as well as A plurality of wings extend outwardly from the central opening across the coupling surface.

12. The base of claim 11, wherein at least a portion of a wall of each of the plurality of wings is curved.

13. The susceptor of claim 11, wherein three or more wings extend radially outward from the central opening.

14. The susceptor of claim 11, wherein the susceptor is formed of a graphite material.

15. The susceptor of claim 11, wherein the substrate supporting surface is circular.

16. A shaft configured for use in semiconductor processing, comprising: First distal end; a second distal end, the second distal end being opposite to the first distal end; as well as a shaft coupling portion coupled to the first distal end of the shaft and comprising: coupling contact surface; as well as A plurality of protrusions extend outwardly from a central portion of the coupling contact surface to engage the coupling contact surface.

17. The shaft of claim 16, further comprising a plurality of features on the coupling contact surface of the shaft coupling portion.

18. The shaft member of claim 17, wherein the plurality of features are a plurality of grooves extending into the coupling contact surface.

19. The shaft member of claim 16, wherein there are three or more protrusions.

20. The shaft of claim 16, wherein the second distal end of the shaft further comprises a plurality of grooves.

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