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US-20260130174-A1 - ELECTROSTATIC CHUCK PEDESTAL HEATER FOR HIGH BOW WAFERS

US20260130174A1US 20260130174 A1US20260130174 A1US 20260130174A1US-20260130174-A1

Abstract

An electrostatic chuck (ESC) pedestal heater that includes a pedestal body and a surface on the pedestal body for receiving a substrate such as a high bow wafer. An electrode is embedded in the pedestal body to selectively generate an electrostatic force. The ESC pedestal heater includes a substrate contact surface that is raised to a height above the surface on the pedestal body and includes an inner seal band, an intermediate seal band, and an outer seal band extending. In the substrate contact surface, main spokes are provided that extend outward from the inner seal band to the outer seal band, and ancillary spokes may be provided between the main spokes in the region between the intermediate and outer seal bands. Additionally, contact areas or dots are provided in the substrate contact surface in the spaces between the bands and spokes.

Inventors

  • Shubham Garg
  • Jaeyong Cho
  • Amit MISHRA
  • Akshay Phadnis

Assignees

  • ASM IP HOLDING B.V.

Dates

Publication Date
20260507
Application Date
20251222

Claims (20)

  1. 1 . A pedestal, comprising: a pedestal body; and a substrate contact surface that is raised to a height above, and protruding from, the pedestal body, wherein the substrate contact surface comprises: a first seal band extending circumferentially at a first diameter on the pedestal body; and a second seal band extending circumferentially at a second diameter on the pedestal body, wherein the second diameter is one of greater or less than the first diameter, wherein at least one of: the first seal band has a first width that is greater than a second width of the second seal band, or the second width of the second seal band is greater than the first width of the first seal band.
  2. 2 . The pedestal of claim 1 , further comprising a third seal band extending circumferentially at a third diameter on the pedestal body, wherein the second diameter is greater than the first diameter, wherein the third diameter is greater than the second diameter, and wherein the first seal band is an inner seal band, the second seal band is an intermediate seal band, and the third seal band is an outer seal band, wherein the first width of the inner seal band is greater than the second width of the intermediate seal band.
  3. 3 . The pedestal of claim 2 , wherein a third width of the outer seal band is greater than at least one of the first width of the inner seal band or the second width of the intermediate seal band.
  4. 4 . The pedestal of claim 2 , wherein the inner seal band and the intermediate seal band each comprise a first section arranged proximate to and separated from a second section by a gap.
  5. 5 . The pedestal of claim 2 , wherein the substrate contact surface further comprises a plurality of contact areas disposed in an intermediate region between the inner seal band and the intermediate seal band and in an outer region between the intermediate seal band and the outer seal band.
  6. 6 . The pedestal of claim 2 , wherein the substrate contact surface further comprises a set of spokes each extending radially outward from the inner seal band to the outer seal band.
  7. 7 . The pedestal of claim 1 , further comprising a third seal band extending circumferentially at a third diameter on the pedestal body, wherein the second diameter is greater than the third diameter, wherein the first diameter is greater than the second diameter, and wherein the first seal band is an outer seal band, the second seal band is an intermediate seal band, and the third seal band is an inner seal band, wherein the first width of the outer seal band is greater than the second width of the intermediate seal band.
  8. 8 . The pedestal of claim 7 , wherein the substrate contact surface further comprises a set of ancillary spokes each extending radially outward from the intermediate seal band to the outer seal band.
  9. 9 . The pedestal of claim 8 , wherein a third width of the inner seal band is greater than the second width of the intermediate seal band.
  10. 10 . The pedestal of claim 1 , wherein a ratio of an area of the substrate contact surface to an area of a surface on the pedestal body from which the substrate contact surface protrudes is less than 10 percent.
  11. 11 . A pedestal, comprising: a pedestal body; and a substrate contact surface that is raised to a height above, and protruding from, the pedestal body, wherein the substrate contact surface includes a first seal band extending circumferentially at a first diameter about a point on the pedestal body, and a second seal band extending circumferentially at a second diameter greater than the first diameter about the point on the pedestal body, and wherein the substrate contact surface further comprises a set of spokes each extending radially outward from the first seal band to the second seal band.
  12. 12 . The pedestal of claim 11 , wherein the set of spokes includes six spokes.
  13. 13 . The pedestal of claim 11 , wherein the first seal band has a width greater than a width of the second seal band.
  14. 14 . The pedestal of claim 11 , wherein the first seal band and the second seal band each comprise a first section arranged proximate to and separated from a second section by a gap.
  15. 15 . The pedestal of claim 11 , wherein the substrate contact surface further comprises a plurality of contact areas disposed in a region of the pedestal body between the first seal band and the second seal band.
  16. 16 . The pedestal of claim 11 , further comprising a third seal band extending circumferentially at a third diameter about the point on the pedestal body, wherein the third diameter is greater than the first diameter and less than the second diameter, wherein the substrate contact surface further comprises a set of ancillary spokes each extending radially outward from the third seal band to the second seal band.
  17. 17 . An apparatus, comprising: a pedestal; and a substrate contact surface extending outward, and protruding, from the pedestal, wherein the substrate contact surface comprises a set of spokes each extending radially outward from a point on the pedestal, and wherein the set of spokes is configured to contact a substrate when the substrate is disposed on the pedestal.
  18. 18 . The apparatus of claim 17 , wherein the substrate contact surface includes a first seal band extending circumferentially at a first diameter about a point on the pedestal and a second seal band extending circumferentially at a second diameter, which is greater than the first diameter, about the point on the pedestal, wherein each spoke of the set of spokes extends between the first seal band and the second seal band.
  19. 19 . The apparatus of claim 18 , wherein a width of the second seal band is greater than a width of the first seal band.
  20. 20 . The apparatus of claim 18 , further comprising a third seal band extending circumferentially at a third diameter about the point on the pedestal body, wherein the third diameter is greater than the second diameter, wherein the substrate contact surface further comprises a set of ancillary spokes each extending radially outward from the second seal band to the third seal band.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of, and claims priority to and the benefit of, U.S. patent application Ser. No. 18/138,776, filed Apr. 25, 2023 and entitled “ELECTROSTATIC CHUCK PEDESTAL HEATER FOR HIGH BOW WAFERS,” which is a nonprovisional of, and claims priority to and the benefit of, U.S. Provisional Patent Application No. 63/335,811, filed Apr. 28, 2022 and entitled “ELECTROSTATIC CHUCK PEDESTAL HEATER FOR HIGH BOW WAFERS,” all of which are hereby incorporated by reference herein. FIELD OF THE DISCLOSURE The present disclosure relates generally to methods and systems for heating wafers in a wafer processing or reactor system, and, more particularly, to an electrostatic chuck (ESC) pedestal heater, for use in a reaction chamber, that is adapted for use with high bow wafers. BACKGROUND OF THE DISCLOSURE Semiconductor processing techniques, including atomic layer deposition (ALD) and chemical vapor deposition (CVD), are often used for forming thin films of materials on substrates, such as silicon wafers. To carry out such processing, reactor systems or tools are used that have a reaction chamber in which a substrate holder is positioned and used for holding wafers during wafer processing steps. In many situations, the substrate holder is provided as the upper portion of a pedestal heater that is used to heat the substrate and includes lift pins to raise and lower the received wafer relative to the upper surface of the substrate holder. In particular, electrostatic chucks (ESCs) are used as the substrate holder of pedestal heaters in many semiconductor processing applications including etching, CVD, ion implantation, and other processing in reactor system or tools. ESCs are typically made of bulk ceramics and have high resistance to plasma and process gas. The built-in heater ensures high in-plane temperature uniformity and contributes to the semiconductor manufacturing processes that are required to support further miniaturization of semiconductors. An internal electrode in the ESC is embedded to utilize the electrostatic force generated between this structure and the wafer (e.g., a silicon wafer) placed on the ESC surface. In addition to their use for silicon wafer mounting, ESCs are used to provide flatness correction during the semiconductor manufacturing process as bowing may occur in some wafer-based device designs. For example, NAND flash memory devices have one of the highest number of film stacks, which can lead to high stress on wafers and can cause these wafers to bow. During processing, bowed wafers may not make good thermal contact with the pedestal heater surface, which can create an undesirably large thermal gradient that can cause less desirable deposition quality. Additionally, when deposited, bowed wafers can get higher backside deposition levels that may eventually need to be cleaned resulting in unwanted additional steps being included in device manufacturing involving bowed wafers. Some ESC designs include minimum contact area (MCA) dots on the chuck's upper surface, and the MCA dots have, in some applications, been useful in flattening a wafer received on the ESC. However, MCA dots are often not efficient in providing uniform clamping force on a wafer or clamping saddle-shaped wafers. Hence, there is a demand for improved ESC pedestal heater designs for use in reactor systems that facilitate more efficient processing involving bowed wafers and that minimize the need for added cleaning steps to remove backside deposition. SUMMARY OF THE DISCLOSURE This summary is provided to introduce a selection of concepts in a simplified form. These concepts are described in further detail in the detailed description of example embodiments of the disclosure below. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. In some embodiments of the description, an electrostatic chuck (ESC) pedestal heater is provided for use in a variety of reactor systems and/or reaction chamber assemblies. The ESC pedestal heater includes a pedestal body and a surface (which may be labeled an ESC surface) on the pedestal body for receiving a substrate (such as, but not limited to a high bow wafer). An electrode is embedded in the pedestal body that operable to selectively generate an electrostatic force between the substrate and the surface to secure the substrate to the pedestal body. The ESC pedestal heater includes substrate contact surface that is raised to a height above the surface on the pedestal body, and this surface includes: (a) an inner seal band extending at a first diameter about a center of the surface on the pedestal body; (b) an intermediate seal band extending at a second diameter greater than the first diameter about the center of the surface on the pedestal body; and (c) an outer seal band extending at a third diameter greater