Low contact area substrate support for an etching chamber

Abstract

Embodiments of a substrate support for use in a processing chamber are provided. In some embodiments, the substrate support includes a base having an upper surface configured to receive lift pins, a first annular region proximate an edge of the base, and a second annular region disposed between the first annular region and the center of the base, wherein the base includes a first plurality of holes extending from the upper surface at regular intervals along the first annular region, and a second plurality of holes extending from the upper surface at regular intervals along the second annular region; and non-metallic balls containing alumina, the non-metallic balls being disposed in each of the first plurality of holes and the second plurality of holes, wherein an upper surface of each of the non-metallic balls is elevated relative to the upper surface of the base to define a support surface.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to semiconductor processing equipment. Background Art

[0002] A substrate support is typically used in a semiconductor processing chamber to support a substrate to be processed. One type of substrate support may include a heated pedestal to provide thermal coupling to the substrate during processing such as for an etching process. However, due to the substrate being adhered to the substrate support, a high substrate contact area with the pedestal can result in particulate contamination on the back side of the substrate, scratching of the substrate, or substrate cracking.

[0003] Accordingly, embodiments of an improved substrate support have been provided by the inventors. Summary of the Invention

[0004] Embodiments of a substrate support for use in a processing chamber are provided herein. In some embodiments, the substrate support includes: a pedestal having an upper surface configured to receive lift rods, a first annular region proximate an edge of the pedestal, and a second annular region disposed between the first annular region and the center of the pedestal, wherein the pedestal includes a first plurality of holes extending at regular intervals from the upper surface along the first annular region, and a second plurality of holes extending at regular intervals from the upper surface along the second annular region; and non-metallic balls containing alumina, the non-metallic balls being disposed in each of the first plurality of holes and the second plurality of holes, wherein an upper surface of each of the non-metallic balls is lifted relative to the upper surface of the pedestal to define a support surface.

[0005] In some embodiments, an apparatus for processing a substrate includes: a processing chamber; and a substrate support assembly at least partially disposed in the processing chamber, the substrate support assembly including a first plate and a second plate, the first plate having a plurality of non-metallic balls extending away from an upper surface of the first plate to define a support surface configured to support a substrate, wherein the plurality of non-metallic balls are disposed at regular intervals along a first ring around a center of the first plate and along a second ring concentric with the first ring, the second plate being coupled to the first plate, wherein the second plate has an outer diameter greater than an outer diameter of the first plate, and a plurality of pins extending upward from an upper peripheral surface of the second plate, wherein the upper peripheral surface is defined by a portion of the second plate extending radially outward from an outer sidewall of the first plate; and a rod coupled to the second plate.

[0006] In some embodiments, a processing chamber includes: a chamber body having an internal space; a susceptor disposed in the internal space and having a plurality of non-metallic balls, the plurality of non-metallic balls comprising alumina and extending away from an upper surface of the susceptor to define a support surface configured to support a substrate at a position elevated from the upper surface, wherein the plurality of non-metallic balls are arranged at regular intervals along a first ring around a center of the susceptor and along a second ring concentric with the first ring at regular intervals; and a lift mechanism having a lift rod configured to lift or lower the substrate relative to the support surface, wherein the lift rod is capable of passing through a groove of the susceptor extending from an outer sidewall of the susceptor toward the center of the susceptor.

[0007] Other and further embodiments of the present disclosure are described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The embodiments of the present disclosure outlined above and discussed in more detail below can be understood by reference to the illustrative embodiments of the present disclosure depicted in the accompanying drawings. However, the drawings merely illustrate typical embodiments of the present disclosure and should not be considered as limiting the scope, as the present disclosure contemplates other equally effective embodiments.

[0009] Figure 1 A schematic diagram of a processing chamber according to some embodiments of the present disclosure is depicted.

[0010] Figure 2 An isometric view of a susceptor according to some embodiments of the present disclosure is depicted.

[0011] Figure 3 A top view of a susceptor according to some embodiments of the present disclosure is depicted.

[0012] Figure 4 A partial cross-sectional view of a susceptor according to some embodiments of the present disclosure is depicted.

[0013] For purposes of facilitating understanding, the same reference numerals are used to represent common elements in the drawings where possible. The drawings are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated into other embodiments without further recitation. DETAILED DESCRIPTION

[0014] Embodiments of a substrate support for use in a processing chamber are provided. The substrate support includes a base having an upper surface for supporting a substrate. Advantageously, the substrate support includes a non-metallic element elevated relative to the upper surface of the base to define a support surface having a low contact area with the substrate when the substrate is placed on the substrate support. The non-metallic element is advantageously positioned to provide a low contact area with the substrate while providing sufficient thermal coupling with the substrate. The low contact area of the substrate advantageously reduces or avoids substrate scratching, contamination, or sticking.

[0015] Figure 1 A schematic side view of a processing chamber (e.g., a plasma processing chamber) in accordance with some embodiments of the present disclosure is depicted. In some embodiments, the plasma processing chamber is an etch processing chamber. However, other types of processing chambers configured for different processes may also be used or modified for use with the embodiments of the substrate support described herein.

[0016] Chamber 100 is a vacuum chamber suitably adapted to maintain a pressure below atmospheric pressure within chamber interior space 120 during substrate processing. Chamber 100 includes a chamber body 106 covered by a lid 104, the lid 104 enclosing a processing space 122 located in the upper half of chamber interior space 120. Chamber 100 may also include one or more shields surrounding various chamber components to avoid unwanted reactions between such components and ionized processing materials. Chamber body 106 and lid 104 may be made of a metal such as aluminum. Chamber body 106 may be grounded by coupling to ground 116.

[0017] A substrate support 124 is disposed within chamber interior space 120 to support and hold a substrate 108, such as, for example, a semiconductor wafer or other such substrate. Substrate support 124 generally may include a base 136 and a hollow support post 112 for supporting base 136. In some embodiments, base 136 is a circular sheet of aluminum. Hollow support post 112 provides conduits to supply, for example, backside gas, process gas, vacuum clamping, fluids, coolant, power, etc. to base 136. In some embodiments, a slit valve 132 is coupled to at least one of chamber body 106 and lid 104 to facilitate transfer of substrate 108 into and out of chamber 100.

[0018] In some embodiments, hollow support post 112 is coupled to a lift mechanism 113, such as an actuator or motor, that provides movement of base 136 between a processing position, as Figure 1Vertical movement between the shown position (not shown) and the transfer position. The bellows assembly 110 is disposed around the hollow support rod 112 and coupled between the base 136 and the bottom surface 126 of the chamber 100 to provide a flexible seal that allows vertical movement of the base 136 while preventing leakage of vacuum from within the chamber 100. The bellows assembly 110 also includes a lower bellows flange 128 that contacts an O-ring or other suitable sealing element, and the lower bellows flange 128 contacts the bottom surface 126 to help prevent leakage of the chamber vacuum.

[0019] The substrate lifter 144 may include a lift rod 109 mounted on a platform 140 connected to a rod 142, and the rod 142 is coupled to a second lift mechanism 138 for raising and lowering the substrate lifter 144 so that the substrate 108 can be placed on or removed from the base 136. In some embodiments, the platform 140 has a hoop shape. In some embodiments, the platform 140 has a hoop shape and the lift rod 109 extends radially inward from the platform 140. The base 136 may include a through hole or a groove to accommodate the lift rod 109.

[0020] The chamber 100 is coupled to and in fluid communication with a vacuum system 114 that includes a throttle valve (not shown) and a vacuum pump (not shown) for evacuating the chamber 100. The pressure inside the chamber 100 can be adjusted by adjusting the throttle valve and / or the vacuum pump. The chamber 100 is also coupled to and in fluid communication with a process gas supplier 118 that can supply one or more process gases to the chamber 100 for processing a substrate disposed therein. In some embodiments, the substrate support 124 includes a conduit 150 extending from the upper surface 115 of the base 136 to a vacuum system 141. In some embodiments, the vacuum system 141 includes a vacuum pump configured to provide vacuum clamping at the upper surface 115 of the base 136.

[0021] The temperature of the base 136 can be adjusted to control the temperature of the substrate. For example, the base 136 can be heated using one or more embedded heating elements 148 (such as resistance heaters). The one or more heating elements 148 are coupled to a heater power supply 146 to supply power to the one or more heating elements 148.

[0022] In operation, for example, a plasma 102 can be generated in the chamber interior space 120 to perform one or more processes. The plasma 102 can be generated by coupling power from a plasma power source (e.g., an RF plasma power source 130) to a process gas via one or more electrodes proximate to or within the chamber interior space 120 to ignite the process gas and generate the plasma 102.

[0023] Figure 2 Depicts an isometric view of a pedestal according to some embodiments of the present disclosure. The pedestal 200 may be relative to Figure 1 the pedestal 136 described above. In some embodiments, the pedestal 200 includes a first plate 226 disposed on and coupled to a second plate 228. In some embodiments, the first plate 226 defines an upper portion and the second plate 228 defines a lower portion of the pedestal 200. In some embodiments, the first plate 226 is welded to the second plate 228. The upper surface 216 of the first plate 226 of the pedestal 200 includes an upper surface configured to support a substrate. In some embodiments, the second plate 228 is coupled to the hollow support rod 112.

[0024] In some embodiments, the first plate 226 has a diameter smaller than that of the second plate 228 to create a notch 218 at the upper peripheral edge of the pedestal 200. The notch 218 is defined by the upper peripheral surface 222 of the second plate 228 and the outer sidewall 220 of the first plate 226. In some embodiments, the upper peripheral surface 222 is defined by a portion of the second plate 228 that extends radially outward from the outer sidewall 220 of the first plate 226. In some embodiments, the lip is defined by a portion of the second plate 228 that extends radially outward from the first plate 226.

[0025] The pedestal 200 includes a first annular region 232 near the edge of the pedestal 200 and a second annular region 230 disposed between the first annular region 232 and the center of the pedestal 200. In some embodiments, the pedestal 200 includes a central opening 202 at the center of the pedestal. The central opening 202 may be fluidly coupled to the conduit 150. In some embodiments, one or more openings 206 are arranged adjacent to the central opening 202. One or more openings 206 are configured to receive fasteners to couple the pedestal 200 to other components of the substrate support 124. In some embodiments, the upper surface 216 includes grooves 234 having a suitable pattern to provide vacuum clamping. In some embodiments, the upper surface 216 does not include grooves 234.

[0026] In some embodiments, the pedestal 200 includes one or more grooves 214 that extend radially inward from the outer sidewall 212 of the pedestal 200. In some embodiments, one or more grooves 214 extend into both the first plate 226 and the second plate 228. One or more grooves 214 are configured to receive one or more lifting rods 109. In some embodiments, as Figure 2 shown, one or more grooves 214 include three grooves 214 to receive three lifting rods 109. In some embodiments, two of the one or more grooves 214 are closer to each other than the third groove 214.

[0027] In some embodiments, the base 200 includes a first plurality of holes 205 extending from the upper surface 216. In some embodiments, the first plurality of holes 205 are arranged at regular intervals along a first annular region 232. In some embodiments, the base 200 includes a second plurality of holes 210 extending at regular intervals from the upper surface 216 along a second annular region 230. In some embodiments, the first plurality of holes 205 are six holes. In some embodiments, the second plurality of holes 210 are four holes.

[0028] In some embodiments, a plurality of pins 208 extend upward from the upper peripheral surface 222 of the second plate 228. In some embodiments, at least one pin 208 of the plurality of pins 208 is disposed between adjacent grooves 214 in one or more grooves 214. In some embodiments, a plurality of third holes 204 extend from the upper peripheral surface 222 to at least partially penetrate the second plate 228. In some embodiments, at least one hole 204 of the plurality of third holes 204 is disposed between adjacent pins 208 of the plurality of pins 208. In some embodiments, each hole 204 of the plurality of third holes 204 is disposed between adjacent pins 208 of the plurality of pins 208. In some embodiments, a focusing ring is disposed on the upper peripheral surface 222 of the second plate 228 and is held in place via the plurality of pins 208 and the plurality of holes 204.

[0029] Figure 3 A top view of a base according to some embodiments of the present disclosure is depicted. In some embodiments, the base 200 may include a groove for vacuum clamping (e.g., groove 234), which, for the sake of clarity, is omitted from Figure 3 The base 200 includes a plurality of non-metallic elements 310 disposed in each of the first plurality of holes 205 and the second plurality of holes 210. The plurality of non-metallic elements 310 extend away from the upper surface 216 of the first plate 226 to define a support surface configured to support a substrate. In some embodiments, the plurality of non-metallic elements 310 are non-metallic balls. In some embodiments, the plurality of non-metallic balls 310 are made of alumina (Al2O3) (e.g., sapphire).

[0030] In some embodiments, a plurality of non-metallic elements 310 in the first plurality of holes 205 are arranged at regular intervals around the center of the base 200 along the first ring 308. In some embodiments, the first ring 308 is about 10.5 inches to about 11.5 inches from the center of the base. In some embodiments, the plurality of non-metallic elements 310 are arranged at regular intervals along a second ring 304 concentric with the first ring. In some embodiments, the second ring 304 is about 4.0 inches to about 5.0 inches from the center of the base. The plurality of non-metallic elements 310 are arranged at regular intervals along each of the first ring 308 and the second ring 304, advantageously providing a low contact area between the substrate 108 and the base 200 while providing sufficient support to reduce or avoid deformation of the substrate 108. The plurality of non-metallic elements 310 are advantageously positioned to provide sufficient support to reduce or avoid deformation of the substrate 108 while providing sufficient thermal coupling with the substrate 108.

[0031] Figure 4 A partial cross-sectional view of a base according to some embodiments of the present disclosure is depicted. The lower surface 412 of the second plate 228 may be coupled to the hollow support rod 112. As Figure 4 shown, non-metallic elements 310 having a spherical shape are disposed in the holes 210 of the second plurality of holes 210. The non-metallic elements 310 are placed on the bottom surface 406 of the holes 210 and fit between the side walls 408 of the holes 210.

[0032] The non-metallic elements 310 have an upper surface 404 that is at a lift distance 410 from the upper surface 216 of the base 200. In some embodiments, the upper surface 404 of the non-metallic elements 310 is lifted from the upper surface 216 of the base 200 by a distance 410 of about 0.005 inches to about 0.015 inches. In some embodiments, the holes 210 have a diameter that is slightly smaller than the diameter of the non-metallic elements 310. In some embodiments, the non-metallic elements 310 have a diameter of about 0.10 inches to about 0.20 inches.

[0033] 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 of the present disclosure.

Claims

1. A substrate support, comprising: A base, the base having an upper surface configured to receive a lifting rod, a first annular region at an edge of the upper surface of the base, and a second annular region disposed between the first annular region and the center of the base, wherein the base includes a first plurality of holes extending at regular intervals along the first annular region from the upper surface, and a second plurality of holes extending at regular intervals along the second annular region from the upper surface, wherein the base includes a first plate and a second plate, the first plate having an upper surface defining the upper surface of the base, the second plate being coupled to a lower surface of the first plate, wherein the second plate has an outer diameter larger than the outer diameter of the first plate, the base includes a notch at an upper peripheral edge of the base, the notch being defined by an upper peripheral surface of the second plate and an outer sidewall of the first plate, wherein the upper peripheral surface includes a plurality of third holes, and further includes a plurality of pins extending upward from the upper peripheral surface at a plurality of positions separated from the plurality of third holes, and wherein at least one third hole is disposed between adjacent pins among the plurality of pins; and Non-metallic balls, the non-metallic balls containing alumina, the non-metallic balls being disposed in each of the first plurality of holes and the second plurality of holes, wherein an upper surface of each of the non-metallic balls is lifted relative to the upper surface of the base to define a support surface.

2. The substrate support according to claim 1, further comprising a heating element disposed in the base.

3. The substrate support according to claim 1, wherein the first plurality of holes are six holes.

4. The substrate support according to claim 3, wherein each of the non-metallic balls disposed in the first plurality of holes is 10.5 inches to 11.5 inches from the center of the base.

5. The substrate support according to claim 1, wherein the second plurality of holes are four holes.

6. The substrate support according to claim 5, wherein each of the non-metallic balls disposed in the second plurality of holes is 4.0 inches to 5.0 inches from the center of the base.

7. The substrate support according to any one of claims 1 to 6, further comprising a second groove and a third groove extending radially inward from an outer sidewall of the base to receive a second lifting rod and a third lifting rod, respectively.

8. The substrate support according to any one of claims 1 to 6, wherein the base includes an upper portion and a lower portion, and a lip extending radially outward from the lower portion of the base.

9. The substrate support according to any one of claims 1 to 6, wherein the upper surface of the non-metallic balls is lifted 0.005 inches to 0.015 inches from the upper surface of the base.

10. The substrate support according to any one of claims 1 to 6, wherein the upper surface includes a groove extending radially inward from an outer sidewall of the base, the groove being configured to receive the lifting rod.

11. A processing chamber, comprising: A chamber body having an internal space; A substrate support as claimed in any one of claims 1 to 6, the substrate support being disposed in the internal space; and A lifting mechanism having a lifting rod configured to lift or lower a substrate relative to the support surface, wherein the lifting rod is capable of passing through a groove of the base extending from an outer sidewall of the base towards the center of the base.

12. The processing chamber as claimed in claim 11, wherein the first annular region and the second annular region are concentric.

13. The processing chamber as claimed in claim 11, wherein the plurality of non-metallic balls have a diameter of 0.10 inches to 0.20 inches.

14. The processing chamber as claimed in claim 11, wherein the upper surface of the plurality of non-metallic balls is lifted 0.005 inches to 0.015 inches from the upper surface of the base.

15. A processing chamber, comprising: A chamber body having an internal space; A substrate support as claimed in any one of claims 1 to 6, the substrate support being disposed in the internal space, wherein the base of the substrate support comprises a rod coupled to the second plate.

16. The processing chamber as claimed in claim 15, wherein the plurality of pins extend upward from the upper peripheral surface of the second plate.

17. The processing chamber as claimed in claim 16, further comprising a focusing ring disposed on the upper peripheral surface of the second plate and held in place by a plurality of pins.

18. The processing chamber as claimed in any one of claims 15 to 17, wherein the non-metallic balls are made of sapphire.

19. The processing chamber as claimed in any one of claims 15 to 17, wherein the plurality of non-metallic balls extend 0.005 inches to 0.015 inches away from the upper surface of the first plate.

20. The processing chamber as claimed in any one of claims 15 to 17, wherein the plurality of non-metallic balls have a diameter of 0.10 inches to 0.20 inches.

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