WO2022076740A1

WO2022076740A1 - Heated substrate support to minimize heat loss and improve uniformity

Info

Publication number: WO2022076740A1
Application number: PCT/US2021/054047
Authority: WO
Inventors: Pavankumar Ramanand HARAPANHALLI; Gangadhar Sheelavant; Sudhir R. Gondhalekar
Original assignee: Applied Materials, Inc.
Priority date: 2020-10-09
Filing date: 2021-10-07
Publication date: 2022-04-14
Also published as: JP2023545067A; KR20230079218A; TW202226413A; CN116420218A

Abstract

Embodiments of substrate support for use in a process chamber are provided herein. In some embodiments, a substrate support for use in a process chamber includes: a heater plate having an upper surface to support a substrate and a lower surface opposite the upper surface, wherein the heater plate comprises a first material having a first coefficient of thermal conductivity, and wherein sidewalls of the heater plate and the lower surface of heater plate are covered with a cover plate comprising a second material having a second coefficient of thermal conductivity less than the first coefficient of thermal conductivity; a hollow shaft coupled to the heater plate, wherein the hollow shaft comprises a third material having a third coefficient of thermal conductivity less than the first coefficient of thermal conductivity; and one or more heating elements disposed in the heater plate.

Description

HEATED SUBSTRATE SUPPORT TO MINIMIZE HEAT LOSS AND IMPROVE UNIFORMITY

FIELD

[0001] Embodiments of the present disclosure generally relate to substrate processing equipment.

BACKGROUND

[0002] Substrate processing equipment generally includes a process chamber configured to perform certain processes on a substrate, for example, chemical vapor deposition, atomic layer deposition, annealing, or the like. Substrate supports for use in the process chamber typically include a pedestal to support a substrate coupled to a hollow shaft that provides a conduit for fluids, power, gas, or the like to the pedestal. The pedestal may also include a heater embedded therein to provide heat to the substrate for certain substrate processes. With conventional pedestals, the inventors have observed that heat from the heater is transferred away from the substrate, resulting in heat loss to a bottom surface of the pedestal and the shaft. Also, with conventional pedestals, the inventors have observed that temperature varies across an upper surface of the pedestal.

[0003] Accordingly, the inventors have provided embodiments of improved substrate supports.

SUMMARY

[0004] Embodiments of substrate support for use in a process chamber are provided herein. In some embodiments, a substrate support for use in a process chamber includes: a heater plate having an upper surface to support a substrate and a lower surface opposite the upper surface, wherein the heater plate comprises a first material having a first coefficient of thermal conductivity, and wherein sidewalls of the heater plate and the lower surface of heater plate are covered with a cover plate comprising a second material having a second coefficient of thermal conductivity less than the first coefficient of thermal conductivity; a hollow shaft coupled to the heater plate, wherein the hollow shaft comprises a third material having a third coefficient of thermal conductivity less than the first coefficient of thermal conductivity; and one or more heating elements disposed in the heater plate.

[0005] In some embodiments, a substrate support for use in a process chamber includes: a heater plate that includes an upper surface for supporting a substrate and a lower surface opposite the upper surface, wherein the heater plate comprises a first material having a first coefficient of thermal conductivity greater than 100 watts per meter-kelvin (W/(m-K)), and wherein sidewalls of the heater plate and the lower surface of heater plate are covered with a cover plate comprising a second material having a second coefficient of thermal conductivity less than the first coefficient of thermal conductivity; a hollow shaft coupled to the heater plate, wherein the hollow shaft comprises the second material; and one or more heating elements disposed in the heater plate.

[0006] In some embodiments, a process chamber includes: a chamber body defining an interior volume; and a substrate support at least partially disposed in the interior volume, wherein the substrate support comprises: a heater plate that includes one or more heating elements disposed therein and includes an upper surface for supporting a substrate, wherein the heater plate comprises a first material having a first coefficient of thermal conductivity, and wherein sidewalls of the heater plate and a lower surface of the heater plate are covered with a cover plate comprising a second material having a second coefficient of thermal conductivity less than the first coefficient of thermal conductivity; and a hollow shaft coupled to the heater plate, wherein the hollow shaft comprises a third material having a third coefficient of thermal conductivity less than the first coefficient of thermal conductivity.

[0007] Other and further embodiments of the present disclosure are described below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Embodiments of the present disclosure, briefly summarized above and discussed in greater detail below, can be understood by reference to the illustrative embodiments of the disclosure depicted in the appended drawings. However, the appended drawings illustrate only typical embodiments of the disclosure and are therefore not to be considered limiting of scope, for the disclosure may admit to other equally effective embodiments.

[0009] Figure 1 is a schematic side view of a process chamber in accordance with at least some embodiments of the present disclosure.

[0010] Figure 2 is a schematic cross-sectional side view of a substrate support in accordance with at least some embodiments of the present disclosure.

[0011] Figure 3 is a schematic cross-sectional side view of a substrate support in accordance with at least some embodiments of the present disclosure.

[0012] Figure 4 is a schematic cross-sectional side view of a substrate support in accordance with at least some embodiments of the present disclosure.

[0013] Figure 5 is a schematic cross-sectional side view of a substrate support in accordance with at least some embodiments of the present disclosure.

[0014] Figure 6 is a partial schematic cross-sectional side view of a heater plate in accordance with at least some embodiments of the present disclosure.

[0015] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The figures are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

DETAILED DESCRIPTION

[0016] Embodiments of a substrate support are provided herein. The substrate support generally includes a heater plate coupled to a hollow shaft. The inventors have observed that radiative heat loss and conductive heat loss from the heater plate negatively affects substrate processing uniformity and power consumption. The embodiments of substrate supports provided herein comprise the heater plate made of a material having a first coefficient of thermal conductivity. The heater plate is covered on the sidewalls and lower surface thereof with a second material having a second coefficient of thermal conductivity lower than the first coefficient of thermal conductivity to advantageously reduce heat loss from the heater plate. Reduced heat loss from the heater plate advantageously improves heat uniformity provided to a substrate disposed on the substrate support.

[0017] Figure 1 is a schematic side view of a process chamber 100 in accordance with at least some embodiments of the present disclosure. The configuration and arrangement of components of the process chamber 100 shown in Figure 1 is merely exemplary and not meant to be limiting. In addition, conventional components or other details not necessary for the understanding of the disclosure are omitted from the Figures so as not to obscure the disclosure. In addition, upper, lower, top, and bottom, as used in the disclosure, are relative to the orientation in the drawings and not meant to be limiting. As depicted in Figure 1 , the process chamber 100 includes a chamber body 138 having an interior volume 132. A substrate support 150 is disposed in the interior volume 132. The substrate support 150 may generally comprise a heater plate 140, or pedestal, and a hollow shaft 134 for supporting the heater plate 140. In some embodiments, the heater plate 140 is circular in shape. In some embodiments, the heater plate 140 comprises a ceramic material. The hollow shaft 134 provides a conduit to provide, for example, backside gases, process gases, vacuum chucking, fluids, coolants, power, or the like, to the heater plate 140.

[0018] A substrate 102 is shown disposed on the heater plate 140. In some embodiments, the substrate support 150 is coupled to a gas element 110. In some embodiments, the substrate support 150 is a vacuum chuck and the gas element 110 is a vacuum pump or other suitable vacuum source. In such embodiments, a vacuum region 104 is formed between an upper surface of the heater plate 140 and the substrate 102. In some embodiments, a pressure sensor, such as a pressure gauge 130 is operatively coupled to the vacuum region 104 to measure the backside pressure in the vacuum region 104. In some embodiments, the gas element 110 is a gas supply configured to provide a backside gas to an upper surface of the heater plate 140. In some embodiments, the heater plate 140 includes a first gas channel 108 to provide at least one of vacuum pressure or backside gas to an upper surface of the heater plate 140. The heater plate 140 includes one or more heating elements 112, such as resistive heating elements, coupled to a heater power source 114. [0019] The chamber body 138 includes an opening, such as a slit valve 106 that selectively opens the chamber body 138 to facilitate moving substrates into and out of the interior volume 132 of the chamber body 138, for example, via a substrate transfer robot 142. In some embodiments, control of the substrate transfer robot 142 facilitates control of the position of the substrate 102 over the substrate support 150, and ultimately, of the position of the substrate 102 on the substrate support 150 when transferred from the substrate transfer robot 142 to the substrate support 1500. A plurality of lift pins 128 may be provided to assist in the transfer of the substrate 102 between the substrate transfer robot 142 and the substrate support 150.

[0020] The process chamber 100 is configured for performing one or more of a variety of processes, such as deposition processes, for example, chemical vapor deposition (CVD) or plasma enhanced chemical vapor deposition (PECVD). A gas source 116 is coupled to the interior volume 132 of the chamber body 138 to provide process gases for substrate processing (e.g., deposition). In some embodiments, the gas source 116 provides at least one inert gas, such nitrogen gas or a noble gas (such as argon or the like). A pump 126 is coupled to the interior volume 132 to maintain a desired pressure within the chamber body 138 and to remove process gases and processing byproducts during processing.

[0021] In some embodiments, to facilitate control of the process chamber 100, a controller 118 is coupled to components of the process chamber 100, including the pressure gauge 130, the substrate transfer robot 142, and the like. The controller 118 may be any form of general-purpose computer processor that can be used in an industrial setting for controlling various chambers and sub-processors. The controller includes a central processing unit (CPU) 120, memory 122, and support circuits 124. The memory, or computer-readable medium, 122 of the CPU 120 may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. The support circuits 124 are coupled to the CPU 120 for supporting the processor. [0022] Figure 2 is a schematic cross-sectional side view of the substrate support 150 in accordance with at least some embodiments of the present disclosure. The substrate support 150 includes the heater plate 140 having an upper surface 210 to support a substrate 102 and a lower surface 212 opposite the upper surface 210. The heater plate 140 comprises a first material having a first coefficient of thermal conductivity. In some embodiments, the first coefficient of thermal conductivity is greater than 130 watts per meter-kelvin (W/(m-K)). In some embodiments, the first coefficient of thermal conductivity is between about 130 and about 190 watts per meter-kelvin (W/(m-K)).

[0023] At least one of the sidewalls 214 of the heater plate 140 and the lower surface 212 of heater plate 140 are covered with a cover plate 220 comprising a second material having a second coefficient of thermal conductivity less than the first coefficient of thermal conductivity. In some embodiments, an upper surface of the cover plate 220 is coplanar with the upper surface 210 of the heater plate 140. In some embodiments, the second coefficient of thermal conductivity is less than 100 watts per meter-kelvin (W/(m-K)). In some embodiments, the second coefficient of thermal conductivity is about 20 percent to about 70 percent of the first coefficient of thermal conductivity.

[0024] In some embodiments, a hollow shaft 206 is coupled to the heater plate 140. In some embodiments, the hollow shaft 206 may be the hollow shaft 134. The hollow shaft 206 comprises a third material having a third coefficient of thermal conductivity less than the first coefficient of thermal conductivity. In some embodiments, the third coefficient of thermal conductivity is less than 100 watts per meter-kelvin (W/(m-K)). In some embodiments, the third material of the hollow shaft 206 comprises the second material. In some embodiments, the hollow shaft 206 is coupled to the heater plate 140 vertically below the heater plate 140. The substrate support may include one or more lift pin openings 230 extending through the heater plate 140 and the cover plate 220 to accommodate lift pins such as the lift pins 128. In some embodiments, the one or more lift pin openings 230 are disposed radially outward of the hollow shaft 206. [0025] In some embodiments, the heater plate 140 is made of aluminum nitride (AIN), aluminum oxide (AI2O3), beryllium oxide (BeO), boron nitride (BN), silicon nitride (Si3N4), or silicon carbide (SiC). In some embodiments, the second material of the cover plate 220 comprises aluminum nitride (AIN), aluminum oxide (AI2O3), beryllium oxide (BeO), boron nitride (BN), silicon nitride (Si3N4), or silicon carbide (SiC). In some embodiments, the heater plate 140 and the cover plate 220 are made of a same material, but with different coefficients of thermal conductivity (/.e., heater plate 140 material having first coefficient of thermal conductivity and cover plate 220 having second coefficient of thermal conductivity). For example, in some embodiments, the heater plate 140 is made of aluminum nitride having the first coefficient of thermal conductivity and the cover plate 220 is made of aluminum nitride having the second coefficient of thermal conductivity.

[0026] Figure 3 is a schematic cross-sectional side view of the substrate support 150 in accordance with at least some embodiments of the present disclosure. In some embodiments, the substrate support 150 includes a hollow shaft 306. In some embodiments, the hollow shaft 306 is the hollow shaft 134. In some embodiments, the hollow shaft 306 comprises the same material as the hollow shaft 206. The hollow shaft 306 has a lower portion 308 and an upper portion 310 coupled to the heater plate 140. In some embodiments, the upper portion 310 extends radially outward from the lower portion 308 and then vertically upward to the heater plate 140. In some embodiments, the hollow shaft 306 is coupled to the heater plate 140 along an outer peripheral edge 316 of the heater plate 140. In some embodiments, the upper portion 310 is coupled to the cover plate 220 at a location radially outward of the heater plate 140 to advantageously reduce heat transfer from the heater plate 140 to the hollow shaft 206. In some embodiments, the one or more lift pin openings 230 extend through the heater plate 140, the hollow shaft 306, and the cover plate 220 to accommodate lift pins such as the lift pins 128.

[0027] Figure 4 is a schematic cross-sectional side view of the substrate support 150 in accordance with at least some embodiments of the present disclosure. In some embodiments, the substrate support 150 includes a hollow shaft 406. In some embodiments, the hollow shaft 406 is the hollow shaft 134. In some embodiments, the hollow shaft 406 comprises the same material as the hollow shaft 206. In some embodiments, the hollow shaft 406 has a lower portion 408 and an upper portion 410 coupled to the heater plate 140. In some embodiments, the upper portion 410 extends radially outward and upward substantially linearly from the lower portion 408 to the heater plate 140. In some embodiments, the upper portion 410 has a conical shape. In some embodiments, the upper portion 410 is coupled to the cover plate 220 at a location radially outward of the heater plate 140 to advantageously reduce heat transfer from the heater plate 140 to the hollow shaft 406. In some embodiments, the one or more lift pin openings 230 extend through the heater plate 140, the hollow shaft 406, and the cover plate 220 to accommodate lift pins such as the lift pins 128.

[0028] Figure 5 is a schematic cross-sectional side view of the substrate support 150 in accordance with at least some embodiments of the present disclosure. In some embodiments, the substrate support 150 includes a hollow shaft 506. In some embodiments, the hollow shaft 506 is the hollow shaft 134. In some embodiments, the hollow shaft 506 comprises the same material as the hollow shaft 206. In some embodiments, the hollow shaft 506 has a lower portion 508 and an upper portion 510 coupled to the heater plate 140. In some embodiments, the upper portion 510 extends radially outward and upward from the lower portion 508 to the heater plate 140. In some embodiments, the upper portion 510 extends radially outward and upward in a non-linear, or rounded, manner. In some embodiments, the upper portion 510 is coupled to the cover plate 220 at a location radially outward of the heater plate 140 to advantageously reduce heat transfer from the heater plate 140 to the hollow shaft 506. In some embodiments, the one or more lift pin openings 230 extend through the heater plate 140, the hollow shaft 506, and the cover plate 220 to accommodate lift pins such as the lift pins 128.

[0029] Figure 6 is a partial schematic cross-sectional side view of a heater plate 140 in accordance with at least some embodiments of the present disclosure. In some embodiments, the heater plate 140 includes an electrode 644 disposed or embedded within the heater plate 140 for generating a plasma in the interior volume 132. The electrode 644 may comprise an RF mesh and coupled to an RF power source 650. In some embodiments, the heater plate 140 comprises a plurality of plates 602 that are bonded, fastened, or otherwise coupled together. For example, in some embodiments, the one or more heating elements 112 may be sandwiched between two of the plurality of plates 602. In some embodiments, the electrode 644 may be sandwiched between two of the plurality of plates 602. In some embodiments, the one or more heating elements 112 are disposed between a first plate 610 and a second plate 620 of the plurality of plates 602. In some embodiments, and the electrode 644 is disposed between the second plate 620 and a third plate 630 of the plurality of plates 602.

[0030] 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.

Claims

Claims:

1. A substrate support for use in a process chamber, comprising: a heater plate having an upper surface to support a substrate and a lower surface opposite the upper surface, wherein the heater plate comprises a first material having a first coefficient of thermal conductivity, and wherein sidewalls of the heater plate and the lower surface of heater plate are covered with a cover plate comprising a second material having a second coefficient of thermal conductivity less than the first coefficient of thermal conductivity; a hollow shaft coupled to the heater plate, wherein the hollow shaft comprises a third material having a third coefficient of thermal conductivity less than the first coefficient of thermal conductivity; and one or more heating elements disposed in the heater plate.

2. The substrate support of claim 1 , wherein the hollow shaft is coupled to the heater plate vertically below the heater plate.

3. The substrate support of claim 1 , wherein the hollow shaft is coupled to the heater plate along an outer peripheral edge of the heater plate.

4. The substrate support of claim 1 , wherein the hollow shaft has a lower portion and an upper portion coupled to the heater plate, wherein the upper portion extends radially outward from the lower portion and then vertically upward to the heater plate.

5. The substrate support of claim 1 , wherein the hollow shaft has a lower portion and an upper portion coupled to the heater plate, wherein the upper portion extends radially outward and upward from the lower portion to the heater plate.

6. The substrate support of any of claims 1 to 5, wherein the first coefficient of thermal conductivity is greater than 130 watts per meter-kelvin (W/(m-K)).

7. The substrate support of any of claims 1 to 5, wherein the heater plate includes one or more lift pin openings.

8. The substrate support of any of claims 1 to 5, wherein the heater plate is made of aluminum nitride (AIN), aluminum oxide (AI2O3), beryllium oxide (BeO), boron nitride (BN), silicon nitride (SisN4), or silicon carbide (SiC).

9. The substrate support of any of claims 1 to 5, wherein the second material comprises aluminum nitride (AIN), aluminum oxide (AI2O3), beryllium oxide (BeO), boron nitride (BN), silicon nitride (Si3N4), or silicon carbide (SiC).

10. The substrate support of any of claims 1 to 5, wherein the first material and the second material comprise the same material.

11. The substrate support of any of claims 1 to 5, wherein the first coefficient of thermal conductivity is greater than 100 watts per meter-kelvin (W/(m-K)).

12. The substrate support of any of claims 1 to 5, wherein the second coefficient of thermal conductivity and the third coefficient of thermal conductivity are less than 100 watts per meter-kelvin (W/(m-K)).

13. The substrate support of any of claims 1 to 5, wherein the second material is a same material as the third material.

14. The substrate support of any of claims 1 to 5, wherein the heater plate is made of aluminum nitride having the first coefficient of thermal conductivity and the cover plate is made of aluminum nitride having the second coefficient of thermal conductivity.

15. A process chamber, comprising: a chamber body defining an interior volume; and a substrate support as described in any of claims 1 to 5 disposed in the interior volume.

16. The process chamber of claim 15, wherein the first coefficient of thermal conductivity is greater than 100 watts per meter-kelvin (W/(m-K)).

17. The process chamber of claim 15, wherein the second coefficient of thermal conductivity and the third coefficient of thermal conductivity are less than 100 watts per meter-kelvin (W/(m-K)).

18. The process chamber of claim 15, wherein at least one of the first material and the second material comprises aluminum nitride (AIN), aluminum oxide (AI2O3), beryllium oxide (BeO), boron nitride (BN), silicon nitride (Si3N4), or silicon carbide (SiC).

19. The process chamber of claim 15, further comprising one or more lift pins disposed in the interior volume and configured to extend through one or more lift pin openings in the heater plate.

20. The process chamber of claim 15, wherein the substrate support is a vacuum chuck.