Heating susceptor design for improved heat transfer and temperature uniformity

Abstract

Embodiments of the present disclosure generally relate to a susceptor for increasing temperature uniformity in a substrate supported thereon. The base comprises a main body, and a heater is embedded in the main body. The body includes a patterned surface including a first region having a first plurality of pillars extending from a base surface of the body at a first height and a second region surrounding the central region, the first region having a second plurality of pillars extending from the base surface of the body at a second height, the second region has a second plurality of posts extending from the base surface at a second height greater than the first height, wherein an upper surface of each of the first and second plurality of posts is substantially coplanar and defines a substrate receiving surface.

Description

[0001] This application is a divisional application of the application with the filing date of December 20, 2019, the application number of 201911327919.0, and the title of "Heated Base Design for Improved Heat Transfer and Temperature Uniformity". Technical Field

[0002] Embodiments of the present disclosure generally relate to methods and apparatuses for heated bases used in semiconductor device manufacturing processes. Background Art

[0003] In the manufacture of electronic devices on a substrate, a substrate such as a semiconductor substrate undergoes many thermal processes. The thermal processes are typically performed in a processing chamber where materials are deposited or removed, or the substrate is heated in a controlled manner. Such processes include epitaxial deposition, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), etching, annealing, and the like.

[0004] The substrate is typically supported in the processing chamber by a heated substrate support or base that transfers heat to the substrate. However, due to the design and layout of the heating mechanism, the base may provide a non-uniform temperature field, which prevents some portions of the substrate from being heated at the same rate as other portions of the substrate. This results in temperature non-uniformity of the heated substrate.

[0005] Therefore, there is a need for an improved base that provides higher temperature uniformity in the substrate heated thereon. Summary of the Invention

[0006] Embodiments of the present disclosure generally relate to an apparatus and method for a base that can be used to increase temperature uniformity in a substrate supported thereon. In one embodiment, a base is disclosed that includes a body in which a heater is embedded. The body includes a patterned surface that includes a first region and a second region surrounding the central region. The first region has a first plurality of posts extending from the base surface of the body at a first height, and the second region has a second plurality of posts extending from the base surface at a second height greater than the first height, wherein the upper surfaces of each of the first plurality of posts and the second plurality of posts are substantially coplanar and define a substrate receiving surface.

[0007] In another embodiment, a pedestal is disclosed, the pedestal including a body with a heater embedded therein. The body includes a patterned surface, the patterned surface including a central region and a peripheral region surrounding the central region, the central region having a first plurality of posts extending from a base surface of the body at a first height, and the second region having a second plurality of posts extending from the base surface at a second height greater than the first height, wherein upper surfaces of each of the first plurality of posts and the second plurality of posts are substantially coplanar and define a substrate receiving surface.

[0008] In another embodiment, a method is disclosed, the method including forming a ceramic body with a heater embedded therein; forming a plurality of posts in an upper surface of the ceramic body such that each post extends from the ceramic body a first height; placing a mask over a first portion of the plurality of posts; and increasing a first depth of a second portion of the plurality of posts. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] To enable a detailed understanding of the above-described features of the present disclosure, a more specific description of the disclosure briefly summarized above may be had by reference to the embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the drawings illustrate only exemplary embodiments and are not to be considered limiting of the scope, and other equivalent embodiments are contemplated.

[0010] Figure 1 is a schematic cross-sectional view of a process chamber according to one embodiment described herein.

[0011] Figure 2A is a top plan view of a pedestal of one embodiment having a patterned surface Figure 1 thereof.

[0012] Figure 2B is Figure 2A a cross-sectional view of the pedestal thereof.

[0013] Figures 3A to 3D is a series of cross-sectional views showing one embodiment of a pedestal manufacturing method as shown and described in Figure 2A and Figure 2B herein.

[0014] Figures 4A to 4D is a series of cross-sectional views showing another embodiment of a pedestal manufacturing method as shown and described in Figure 2A and Figure 2B herein.

[0015] Figures 5 to 7 is a cross-sectional view of pedestals of various other embodiments having a patterned surface with the profile as shown.

[0016] Figure 8Ais a top plan view of a susceptor that can be used in a chamber of Figure 1 as per another embodiment.

[0017] Figure 8B is Figure 8A an enlarged plan view of a portion of the susceptor of

[0018] Figure 9 is a top plan view of a susceptor that can be used in a chamber of Figure 1 as per another embodiment.

[0019] Figure 10 is a top plan view of a susceptor that can be used in a chamber of Figure 1 as per another embodiment.

[0020] For ease of understanding, the same reference numerals have been used throughout the figures to denote the same elements common to the figures where possible. It is contemplated that elements and features of one embodiment may be beneficially incorporated into other embodiments without further recitation. DETAILED DESCRIPTION

[0021] Embodiments of the present disclosure generally relate to a heated susceptor for a process chamber. The heated susceptor includes a patterned surface of grooves surrounding a plurality of protrusions or posts. The posts have different heights on the susceptor. A method for manufacturing the susceptor is also disclosed. The heated susceptor with the patterned surface improves temperature uniformity, which enables more uniform heat transfer to the substrate, improving the temperature uniformity of the substrate clamped or placed on the heated susceptor. The improved temperature uniformity improves the film thickness uniformity of the film being processed on the substrate.

[0022] As used herein, "substrate" refers to any substrate or the surface of a material formed on a substrate on which film processing is performed in a manufacturing process. For example, depending on the application, the substrate surface on which processing can be performed includes materials such as silicon, silicon oxide, strained silicon, silicon on insulator (SOI), carbon-doped silicon oxide, amorphous silicon, doped silicon, germanium, gallium arsenide, glass, sapphire, and any other materials such as metals, metal nitrides, metal alloys, and other conductive materials. Substrates include, but are not limited to, semiconductor substrates. The substrate can be exposed to a pre-treatment process to polish, etch, reduce, oxidize, hydroxylate, anneal, and / or bake the substrate surface. As disclosed in more detail below, in addition to performing film processing directly on the surface of the substrate, any of the film processing steps in the disclosed film processing steps can also be performed on an underlying layer formed on the substrate, and the term "substrate surface" is intended to include such underlying layers as indicated by the context. Thus, for example, in the case where a film / layer or a portion of a film / layer has been deposited on the substrate surface, the exposed surface of the newly deposited film / layer becomes the substrate surface.

[0023] Figure 1 is a schematic cross-sectional view of a processing chamber 100 according to one embodiment described herein. The processing chamber 100 can be a chemical vapor deposition (CVD) chamber, a plasma enhanced chemical vapor deposition (PECVD) chamber, or other thermal process chamber. An exemplary processing chamber that can benefit from the embodiments described herein is the series of PECVD-enabled chambers available from Applied Materials, Inc., Santa Clara, CA. It is contemplated that process chambers of other similar equipment from other manufacturers may also benefit from the embodiments described herein.

[0024] The processing chamber 100 includes a chamber body 102, a susceptor 104 disposed within the chamber body 102, and a lid assembly 106 that is coupled to the chamber body 102 and encapsulates the susceptor 104 within a processing region 120. The lid assembly 106 includes a gas distributor 112. A substrate 107 is provided to the processing region 120 through an opening 126 formed in the chamber body 102.

[0025] An isolator 110 separates the gas distributor 112 from the chamber body 102, and the isolator 110 can be a dielectric material such as ceramic or metal oxide, for example, alumina and / or aluminum nitride. The gas distributor 112 includes an opening 118 for allowing process gas to enter the processing region 120. The process gas can be supplied to the processing chamber 100 via a conduit 114, and the process gas can enter a gas mixing region 116 before flowing through the opening 118. An exhaust port 152 is formed in the chamber body 102 at a location below the susceptor 104. The exhaust port 152 can be connected to a vacuum pump (not shown) to remove unreacted materials and by-products from the processing chamber 100.

[0026] The gas distributor 112 can be coupled to a power source 141, such as an RF generator or a DC power source. The DC power source can supply continuous and / or pulsed DC power to the gas distributor 112. The RF generator can supply continuous and / or pulsed RF power to the gas distributor 112. During operation, the power source 141 is turned on to supply power to the gas distributor 112 to facilitate plasma formation in the processing region 120.

[0027] The base 104 can be formed of a ceramic material, such as a metal oxide or nitride or an oxide / nitride mixture, such as aluminum, aluminum oxide, aluminum nitride, or an aluminum oxide / nitride mixture. The base 104 is supported by a shaft 143. The base 104 can be grounded. The heater 128 is embedded in the base 104. The heater 128 can be a plate, a perforated plate, a mesh, a wire mesh, or any other distributed arrangement. The heater 128 is coupled to a power supply 132 via a connector 130. The power supply 132 can be a power source that controls the heater 128. In some embodiments, the heater 128 can be an electrode such that the base 104 serves as an electrostatic chuck. Thus, the power supply can also be an RF generator. When the heater 128 serves as an electrode, the power supply 132 can be used to control the properties of the plasma formed in the processing region 120 or to assist in generating a plasma within the processing region 120. For example, the power supply 141 and the power supply 132 can be tuned to two different frequencies to facilitate the ionization of multiple species in the processing region 120. In one example, the power supply 141 and the power supply 132 can be used to generate a capacitively coupled plasma within the processing region 120.

[0028] The base 104 includes a patterned surface 142 for supporting the substrate 107. The base 104 may also include a trench 140. The trench 140 can alternatively be an edge ring. The substrate 107 and the trench 140 can be concentrically disposed on the surface 142 of the base 104.

[0029] Figure 2A is a top plan view of one embodiment of the Figure 1 base 104 having the patterned surface 142. Figure 2B is Figure 2A a cross-sectional view of the base 104.

[0030] Figure 2A The illustrated base 104 includes a peripheral ledge 202 surrounded by a trench 140. The patterned surface 142 includes two different regions, such as a central region 200 surrounded by a peripheral region 205. The patterned surface 142 includes a plurality of posts 210 having upper surfaces 215 that define a substrate receiving surface 220. The central region 200 differs from the peripheral region 205 in the height of the posts 210 formed therein. The upper surfaces 215 of each of the plurality of posts 210 are substantially coplanar.

[0031] Each of the plurality of posts 210 is shown as rectangular in a plan view, but the posts 210 can be circular, oval, hexagonal, or other shapes in a plan view. The posts 210 are shown as circular in Figure 8A and Figure 9 . A plurality of lift pin holes 212 are also shown in Figure 2A .

[0032] In some embodiments, the surface area of the central region 200 is less than the surface area of the peripheral region 205. For example, if the diameter of the patterned surface 142 is about 12 inches, the surface area of the peripheral region 205 is about 113 square inches, and the surface area of the central region 200 is about 11 square inches. In some embodiments, the surface area of the peripheral region 205 is about 900% of the surface area of the central region 200. The upper surface 215 of each of the plurality of posts 210 includes a surface roughness (average surface roughness or Ra) of about 40 microinches.

[0033] As Figure 2B shown, the plurality of posts 210 includes a plurality of first posts 225A in the peripheral region 205 and a plurality of second posts 225B in the central region 200. The height 230 of each of the plurality of first posts 225A is greater than the height 235 of the plurality of second posts 225B. The height 230 and the height 235 are measured from the upper surface or the base surface 232 of the base 104. In some embodiments, the height 230 of each of the plurality of first posts 225A is from about 0.002 inches to about 0.0024 inches, such as about 0.0022 inches. In some embodiments, when compared to the height 230 of the plurality of first posts 225A, the height 235 of each of the plurality of second posts 225B is from about 0.0005 inches to about 0.0007 inches, such as about 0.0006 inches. Although only two different heights of the posts 210 are shown (i.e., the height 230 and the height 235), the patterned surface 142 may include additional plurality of posts having heights different from the height 230 and the height 235.

[0034] In some embodiments, the height 230 is about 1.5 times the height 235. In some embodiments, the height 230 is about 2 times the height 235. In some embodiments, the height 230 is about 2.5 times the height 235. In some embodiments, the height 230 is about 3 times the height 235. In some embodiments, the height 230 is about 3.5 times the height 235. In some embodiments, the base surface 232 of the base 104 has an Ra greater than the Ra of the upper surface 215 of each of the plurality of posts 210. For example, the Ra of the base surface 232 is about 63 microinches.

[0035] In other embodiments, the height 235 of each of the plurality of second posts 225B is about 15 micrometers (μm), while the height 230 of each of the plurality of first posts 225A is about 30 μm. In other embodiments, the height 235 of each of the plurality of second posts 225B is about 15 μm, while the height 230 of each of the plurality of first posts 225A is about 55 μm. In other embodiments, the height 235 of each of the plurality of second posts 225B is about 30 μm, while the height 230 of each of the plurality of first posts 225A is about 55 μm.

[0036] The difference in heights 230 and 235, and / or the difference in surface area between the central region 200 and the peripheral region 205, changes the heat transfer rate between the base 104 and the substrate supported thereon. The altered heat transfer rate changes the temperature distribution of the substrate. In some embodiments, the difference in heights 230 and 235 and / or the difference in surface area between the central region 200 and the peripheral region 205 improves the temperature uniformity in the substrate, which improves the deposition uniformity on the substrate. In some embodiments, making the height 235 of each of the plurality of second posts 225B less than the height 230 of each of the plurality of first posts 225A increases the temperature in the center of the substrate. Increasing the temperature at the center of the substrate can improve the temperature uniformity across the substrate, which improves the deposition uniformity on the substrate.

[0037] The heights 230 and 235 of the posts 210 make the base surface 232 of the base 104 a multi-layer structure. For example, compared to the base surface 232 of the peripheral region 205, the base surface 232 of the central region 200 defines a raised surface 240, and the base surface 232 of the peripheral region 205 is referred to as a recessed surface 245 compared to the raised surface 240. Figure 2B The raised surface 240 and the recessed surface 245 of the base 104 shown in define a profile, such as an upside-down or inverted U-shaped profile 250.

[0038] Figures 3A to 3D is shown Figure 2A and Figure 2B are various cross-sectional views of one embodiment of a method of manufacturing the base 104 shown and described in.

[0039] Figure 3A shows a ceramic body 300 in which a heater 128 is embedded. In Figure 3B a plurality of posts 210 are formed in the ceramic body 300 by removing a portion of the surface 302 of the ceramic body 300. The surface 302 becomes the upper surface 215 of the plurality of posts 210. In some embodiments, each post 210 is formed by a machining process, such as a milling process performed on the ceramic body 300.

[0040] AsFigure 3C As shown, after forming a plurality of pillars 210 on the ceramic body, a mask pattern 305 is placed on a part of the ceramic body 300 and all the pillars 210. For example, the mask pattern 305 includes a central mask 310 and a peripheral mask 315. The central mask 310 covers the central portion of the ceramic body 300 and the pillars 210 therein, and corresponds to the central region 200 of the base 104 after forming the pillars. The peripheral mask 315 covers the remaining portions of the pillars 210, and corresponds to the peripheral region 205 of the base 104 after forming the pillars. With the mask pattern 305 in place, a plurality of first pillars 225A are formed to a height 230 by a shot peening process. The central mask 310 shields the central portion of the ceramic body 300 and the pillars 210, and the peripheral mask 315 shields the upper surfaces 215 of the pillars 210 in the peripheral portion of the ceramic body 300.

[0041] As Figure 3D shown, the mask pattern 305 is removed, and a base 104 is formed to have a plurality of first pillars 225A and a plurality of second pillars 225B in the peripheral region 205 and the central region 200, respectively.

[0042] Figures 4A to 4D is a schematic diagram showing Figure 2A and Figure 2B another embodiment of the manufacturing method of the base 104 shown and described in

[0043] Figure 4A shows a ceramic body 300 in which a heater 128 is embedded. In Figure 4B , a first mask pattern 400 is placed on the ceramic body 300 to form a plurality of pillars 210 to a height 415. The first mask pattern 400 includes a plurality of openings 405 formed therein, and a discrete mask 410 that protects the surface 302 of the ceramic body 300.

[0044] In Figure 4C , a second mask pattern 420 is placed on the ceramic body 300. The second mask pattern 420 is similar to the mask pattern 305. The central mask 310 covers the central portion of the ceramic body 300 and the pillars 210 therein, and corresponds to the central region 200 of the base 104 after forming the pillars. The peripheral mask 315 covers the remaining portions of the pillars 210, and corresponds to the peripheral region 205 of the base 104 after forming the pillars. With the mask pattern 305 in place, a plurality of first pillars 225A are formed to a height 230 by a shot peening process. The central mask 310 shields the central portion of the ceramic body 300 and the pillars 210, and the peripheral mask 315 shields the upper surfaces 215 of the pillars 210 in the peripheral portion of the ceramic body 300.

[0045] AsFigure 4D As shown, the second mask pattern 420 is removed, and a susceptor 104 is formed to have a plurality of first posts 225A and a plurality of second posts 225B in the peripheral region 205 and the central region 200, respectively.

[0046] Figures 5 to 7 FIG. is a cross-sectional view of a susceptor 104 of various other embodiments having a patterned surface with the profile shown. In the following figures, various profiles of the susceptor 104 that can be used in the Figure 1 processing chamber 100 are disclosed.

[0047] Figure 5 A susceptor 104 having a U-shaped profile 500 is shown. The U-shaped profile 500 includes a plurality of first posts 225A in the peripheral region 205 and / or on the raised surface 240. The plurality of second posts 225B are in the central region 200 and / or on the recessed surface 245.

[0048] Figure 6 A susceptor 104 having an M-shaped profile 600 is shown. The M-shaped profile includes two sets of a plurality of second posts 225B positioned on the raised surface 240. The raised surface 240 is surrounded by three sets of a plurality of first posts 225A (in the central region and the peripheral region) positioned on the recessed surface 245.

[0049] Figure 7 A susceptor 104 having a W-shaped profile 700 is shown. The W-shaped profile includes three sets of a plurality of second posts 225B positioned on the raised surface 240 (in the central region and the peripheral region). The raised surface 240 is adjacent to one of two sets of a plurality of first posts 225A positioned on the recessed surface 245. Although the Figure 6 and Figure 7 show only two different heights for the plurality of first posts 225A and the plurality of second posts 225B, the patterned surface 142 can include additional plurality of posts having heights different from those shown.

[0050] As the requirements for feature sizes and multi-operation integration processes used in logic and 3D NAND devices continue to increase, it is beneficial to deposit thick films (such as oxide / nitride / carbon-based patterned films, etc.) very uniformly on a silicon substrate using a PECVD process. Thus, the general specifications, as well as local deviations in uniformity with respect to the patterned film, drive the customer specifications. The susceptor 104 as described herein meets or exceeds these specifications.

[0051] In terms of PECVD processing, in order to obtain reliable substrate contact and prevent total contamination of the backside of the substrate (which typically contains device layers), the contact with the substrate must be controlled. This control is achieved through the pattern of posts on the heater, which provides repeatable contact and minimizes problems caused by variable contact, such as defects in the formation of local barrier layers on a perfectly flat heater. However, as a result of this pattern of posts, the local temperature of the substrate varies at each contact location. Although temperature variations were acceptable for previous generations, for current and future nodes, more uniform temperature control is being sought. For example, in a conventional hard mask film, this local temperature variation results in a local variation in thickness of approximately 1%, and a corresponding local variation in the film dielectric constant (k), leading to problems of integration and yield loss. However, the first part of the present disclosure describes a patterned surface 142 that improves substrate temperature uniformity compared to conventional methods. The following sections describe how substrate processing problems resulting from the pattern of posts 210 can be addressed, leading to better substrate temperature uniformity.

[0052] As described herein, extensive testing and simulation were performed on the susceptor 104. The susceptor 104 as described herein improves temperature uniformity by reducing the temperature differential (Δ) in the substrate by 0.4 degrees Celsius or more.

[0053] The testing also included minimizing local temperature variations within the substrate. To minimize local temperature variations, the magnitude of the hot spots resulting from the contact between the substrate and the posts 210 will be minimized. Based on the thermal simulation results, this is achieved by reducing the diameter of each post 210; reducing the height of the posts 210; and / or increasing the density of the posts 210 in the patterned surface 142. However, the negative consequence of reducing the diameter is increased clamping failure and backside damage due to the small post size (i.e., less contact area results in high pressure at the contact area).

[0054] Improving the thermal uniformity of the substrate generally involves increasing the post density and / or reducing the post height. However, reducing the post height constricts the gas flow under the substrate. Reducing the post height may also generate different shear forces on the substrate, which can cause the substrate to slide out of position on the susceptor. Increasing the post density also has the same flow constriction effect and sliding problem as reducing the post height. One simple way to address the flow constriction and / or sliding problem is to make the post diameter smaller. However, this results in a loss of clamping force on the substrate and limits the entry bend of the substrate. Therefore, one solution is to have a high flow rate at the center of the susceptor with smaller diameter posts, but the post diameter increases as the posts move radially away from the center. This method provides a high post-to-substrate contact area and thus a high clamping force applied to the substrate.

[0055] One additional competing factor is that increasing the column density results in thermal non-uniformity, making the hot / cold spots on the substrate distinct (such as the electrode terminal positions in the pedestal 104). This can be addressed by selective post-removal near such hot / cold spots. The problem that may arise is that if too many columns are removed, the column removal may again result in poor thermal uniformity. For example, the removal of columns increases the column pitch and increases the thermal non-uniformity.

[0056] Figure 8A is a top plan view of the pedestal 104 according to another embodiment. Figure 8B is Figure 8A an enlarged plan view of a portion of the pedestal 104. The pedestal 104 described herein can be manufactured according to the above method.

[0057] The pedestal 104 includes a patterned surface 142 having a plurality of columns 210 positioned thereon in a pattern that is substantially radially oriented. For example, a portion of the plurality of columns 210 is positioned in radially oriented rows 800 that are generally straight in a plan view. Another portion of the plurality of columns 210 is arranged in inwardly curved rows 805. Each inwardly curved row 805 has a first portion 810A in the peripheral region 205 and a second portion 810B in the central region 200. The columns 210 in the first portion 810A are generally straight or linear columns 210. The columns 210 in the second portion 810B are generally curved toward the center 812 of the pedestal 104. In the illustrated embodiment, three pairs of radially oriented rows 800 are positioned at approximately 120-degree intervals. A plurality of inwardly curved rows 805 are positioned between pairs of radially oriented rows 800. The center 812 does not include columns to prevent hot or cold spots on the substrate (i.e., the "bare position" described below).

[0058] Figure 8B Shows an edge 815 of the peripheral region 205 of the pedestal 104 at which a portion of the plurality of columns 210 forms a triangular pattern 820. The orientation of the columns 210 in the triangular pattern 820 is generally linear.

[0059] Figure 9 is a top plan view of the pedestal 104 according to another embodiment. The pedestal 104 includes a patterned surface 142 having a plurality of columns 210 positioned thereon in a spirograph pattern 900 (e.g., hypocycloid within a geometric circle and / or epicycloid). The spirograph pattern 900 includes a plurality of spirals 905 formed by the plurality of columns 210. Figure 9The pedestal 104 shown also includes a plurality of bare locations 910 where posts can be positioned. The bare locations 910 correspond to the locations where posts will be formed (based on the remaining pattern or spacing of other posts), but exclude one or more posts to prevent hot or cold spots on the substrate. The pedestal 104 described herein can be manufactured according to the methods described above.

[0060] A plurality of posts 210 are arranged in a plethysmograph pattern 900 to prevent a straight flow path and / or to provide a curved flow path for a gas applied to the back side of a substrate positioned on the pedestal 104. The curved flow path prevents the formation of a high-speed flow pattern that would cause the wafer to slide.

[0061] In some embodiments, as Figures 8A to 9 shown in the plan view, the plurality of posts 210 are circular and each of the plurality of posts 210 includes a diameter of from about 1 millimeter (mm) to about 2 mm. The number of posts 210 (for a 300 mm substrate) is from about 121 to about 2500 posts on the patterned surface 142. The distance between the outermost post 210 of the edge 815 (shown in Figure 8B and the innermost portion of the peripheral ledge 202 is from about 105 mm to about 3 mm. The contact area of the posts 210 is from about 0.14 percent to about 11 percent (the contact area is the total area of the upper surface 215 of each post 210 that contacts the substrate).

[0062] Figure 10 is a top plan view of a pedestal 104 according to another embodiment. The pedestal 104 includes a patterned surface 142 having a plurality of posts 210 positioned thereon in a pattern that is symmetric with respect to a radial axis 1000. Figure 10 The pedestal 104 shown also includes a plurality of bare locations 910 where posts can be positioned. The bare locations 910 correspond to the locations where posts will be formed (based on the remaining pattern or spacing of other posts), but exclude one or more posts to prevent hot or cold spots on the substrate. The pedestal 104 described herein can be manufactured according to the methods described above.

[0063] A plurality of posts 210 are arranged in Figure 10 the symmetric pattern shown to prevent a straight flow path and / or to provide a curved flow path for a gas applied to the back side of a substrate positioned on the pedestal 104. The curved flow path prevents the formation of a high-speed flow pattern that would cause the wafer to slide. For example, Figure 10 the pedestal 104 shown in includes a plurality of serpentine rows of posts 1005 that extend radially from the center of the pedestal 104.

[0064] In some embodiments, as Figures 8A to 10In the plan view shown, the plurality of posts 210 are circular, and each of the plurality of posts 210 includes a diameter of from about 1 millimeter (mm) to about 2 mm. The number of posts 210 (for a 300 mm substrate) is from about 121 posts to about 2500 posts on the patterned surface 142. The distance between the outermost post 210 of the edge 815 (shown in Figure 8B ) and the innermost portion of the peripheral ledge 202 is from about 105 mm to about 3 mm. The contact area of the posts 210 is from about 0.14 percent to about 11 percent (the contact area is the total area of the upper surface 215 of each post 210 in contact with the substrate).

[0065] In some embodiments, the diameter of the posts 210 decreases from the edge to the center. For example, the posts near the edge 815 may have a diameter of about 2 mm, the posts 210 in the central region 200 may have a diameter of about 0.75 mm, and the posts 210 between the edge 815 and the central region 200 may have a diameter of about 1 mm. In other embodiments, the diameter of the posts 210 increases from the edge to the center. The gradual change in the post diameter from the center to the edge maximizes the conductivity, thereby improving substrate handling and increasing thermal uniformity. The increase in the post diameter towards the edge also helps to increase the contact area between the posts and the substrate, which increases the total clamping force applied to the substrate. This is advantageous for substrates with large curvature.

[0066] Although the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof.

Claims

1. A pedestal, the pedestal comprising: A body having a heater disposed therein, wherein the body comprises: A patterned surface, the patterned surface comprising: A first region having a first plurality of posts extending from a base surface of the body; and A second region surrounding the first region, the second region having a second plurality of posts extending from the base surface, wherein upper surfaces of each of the first plurality of posts and the second plurality of posts are substantially coplanar and define a substrate receiving surface, and wherein the patterned surface includes one or more bare positions.

2. The pedestal according to claim 1, wherein an average surface roughness of the base surface is greater than an average surface roughness of the upper surface of each of the posts.

3. The pedestal according to claim 1, wherein each of the first plurality of posts extends from the base surface at a first height, and each of the second plurality of posts extends from the base surface at a second height, the second height being different from the first height.

4. The pedestal according to claim 3, wherein the second height is 1.5 times the first height.

5. The pedestal according to claim 3, wherein the second height is 2 times the first height.

6. The pedestal according to claim 3, wherein the second height is 2.5 times the first height.

7. The pedestal according to claim 3, wherein the second height is 3 times the first height.

8. The pedestal according to claim 3, the pedestal further comprising a third plurality of posts extending from the base surface at a height different from the first height and the second height.

9. The pedestal according to claim 1, wherein a surface area of the first region is smaller than a surface area of the second region.

10. A pedestal, the pedestal comprising: A body having a heater embedded therein, the body comprising: A patterned surface, the patterned surface comprising: A central region having a first plurality of posts extending from a base surface of the body at a first height; and A peripheral region surrounding the central region, the peripheral region having a second plurality of posts extending from the base surface at a second height greater than the first height.

Images