CN-121986010-A - Polishing head with flexure extending through pressure chamber

Abstract

A carrier head for chemical mechanical polishing includes a housing for attachment to a drive shaft, a membrane assembly disposed below a lower carrier body, and a flexure. The membrane assembly includes a membrane support and a flexible membrane secured to the membrane support to define a plurality of pressurizable lower chambers, wherein the flexible membrane has a lower surface that provides a substrate mounting surface. The flexible seal forms a pressurizable upper chamber between the housing and the membrane support. A flexure connects the membrane support to the housing, and the flexure extends through the pressurizable upper chamber.

Inventors

• A. J. nagenggast
• W. R. Fernando
• WU ZHENGXUN
• CHEN KUNXIANG
• S.M. Suniga
• FUJIKAWA TAKASHI
• J. Gurusami
• E.A. Mikhailichenko
• E.L.Liu
• ZHANG HUANBO

Assignees

• 应用材料公司

Dates

Publication Date

20260505

Application Date

20240926

Priority Date

20231003

Claims (20)

1. 1. A carrier head for chemical mechanical polishing, comprising: A housing for attachment to a drive shaft, wherein the housing comprises an upper carrier body and a lower carrier body vertically movable relative to the upper carrier body, A first flexible seal forming a first pressurizable chamber between the upper carrier body and the lower carrier body; a membrane assembly disposed below the lower carrier body, the membrane assembly including a membrane support and a flexible membrane secured to the membrane support to define a plurality of pressurizable lower chambers, the flexible membrane having a lower surface providing a substrate mounting surface, and A second flexible seal forming a second pressurizable chamber between the lower carrier body and the membrane support, and A flexure connecting the membrane support to the lower carrier body, the flexure extending through the second pressurizable chamber.
2. 2. The carrier head of claim 1, wherein a first portion of the second pressurizable chamber above the flexure is fluidly connected to a second portion of the second pressurizable chamber below the flexure.
3. 3. The carrier head of claim 2, wherein the flexure comprises a plurality of apertures fluidly connecting the first portion of the second pressurizable chamber to the second portion of the second pressurizable chamber.
4. 4. The carrier head of claim 2, wherein the flexure comprises a plurality of arcuate members separated by a plurality of gaps.
5. 5. The carrier head of claim 2, wherein the first portion of the second pressurizable chamber is fluidly connected to the second portion of the second pressurizable chamber by a passageway through the lower carrier body.
6. 6. The carrier head of claim 1, wherein the first portion of the second pressurizable chamber is a downwardly protruding annular chamber surrounding the lower carrier body.
7. 7. The carrier head of claim 6, wherein the second portion of the second pressurizable chamber is a disc-shaped chamber extending across substantially all of the support plate.
8. 8. The carrier head of claim 1, wherein the flexure is disposed horizontally between the lower carrier body and the membrane support.
9. 9. The carrier head of claim 8, wherein the flexure is disposed between an annular upper portion of the membrane support and a downward projection of the lower carrier body.
10. 10. The carrier head of claim 1, wherein the membrane support comprises a plate that horizontally spans over the plurality of pressurizable lower chambers.
11. 11. The carrier head of claim 10, wherein the plate is stronger than the flexible membrane.
12. 12. The carrier head of claim 1, further comprising a retaining ring connected to the lower carrier body, wherein wear on the retaining ring results in a reduction in a distance between the membrane support and the lower carrier body.
13. 13. The carrier head of claim 1, wherein the flexure is sufficiently rigid to horizontally center the membrane assembly within the housing.
14. 14. The carrier head of claim 1, wherein the flexure is sufficiently rigid to vertically center the membrane assembly within the housing.
15. 15. A carrier head for chemical mechanical polishing, comprising: A housing for attachment to a drive shaft; a membrane assembly disposed below the lower carrier body, the membrane assembly including a membrane support and a flexible membrane secured to the membrane support to define a plurality of pressurizable lower chambers, the flexible membrane having a lower surface providing a substrate mounting surface, and A flexible seal forming a pressurizable upper chamber between the housing and the membrane support, and A flexure connecting the membrane support to the housing, the flexure extending through the pressurizable upper chamber.
16. 16. The carrier head of claim 15, wherein a first portion of the pressurizable upper chamber above the flexure is fluidly connected to a second portion of the pressurizable upper chamber below the flexure.
17. 17. The carrier head of claim 16, wherein the flexure comprises a plurality of apertures fluidly connecting the first portion of the pressurizable upper chamber to the second portion of the pressurizable upper chamber.
18. 18. The carrier head of claim 16, wherein the flexure comprises a plurality of arcuate members separated by a plurality of gaps.
19. 19. The carrier head of claim 16, wherein the first portion of the pressurizable upper chamber and the second portion of the pressurizable upper chamber are fluidly connected by a passageway through the lower carrier body.
20. 20. The carrier head of claim 15, wherein the first portion of the pressurizable upper chamber is a downwardly protruding annular chamber surrounding the lower carrier body.

Description

Polishing head with flexure extending through pressure chamber Technical Field The present disclosure relates to a carrier head for use in Chemical Mechanical Polishing (CMP). Background Integrated circuits are typically formed on a substrate by sequentially depositing conductive, semiconductive, or insulative layers over a semiconductor wafer. Various fabrication processes require planarization of layers on a substrate. For example, one fabrication step involves depositing a fill layer on a non-planar surface and then planarizing the fill layer. In some applications, the fill layer is planarized until the top surface of the pattern layer is exposed. For example, a metal layer may be deposited on the patterned insulating layer to fill the trenches and holes in the insulating layer. After planarization, the trenches and the remaining portions of the metal in the holes of the pattern layer form vias, plugs, and lines to provide conductive paths between the film circuits on the substrate. As another example, a dielectric layer may be deposited over the patterned conductive layer and then planarized to enable subsequent photolithography steps. Chemical Mechanical Polishing (CMP) is a well-known planarization method. Such planarization methods typically require the substrate to be mounted on a carrier head. The exposed surface of the substrate is typically placed against a rotating polishing pad. The carrier head provides a controllable load on the substrate to urge the substrate against the polishing pad. Polishing slurry containing abrasive particles is typically supplied to the surface of the polishing pad. Disclosure of Invention In one aspect, a carrier head for chemical mechanical polishing includes a housing for attachment to a drive shaft, a membrane assembly disposed below a lower carrier body, and a flexure. The membrane assembly includes a membrane support and a flexible membrane secured to the membrane support to define a plurality of pressurizable lower chambers, wherein the flexible membrane has a lower surface that provides a substrate mounting surface. The flexible seal forms a pressurizable upper chamber between the housing and the membrane support. A flexure connects the membrane support to the housing, and the flexure extends through the pressurizable upper chamber. In another aspect, a chemical mechanical polishing system includes a platen, a carrier head, and a controller. The carrier head includes a housing for attachment to the drive shaft, and the housing includes an upper carrier body and a lower carrier body vertically movable relative to the upper carrier body. The first flexible seal forms a first pressurizable chamber between the upper carrier body and the lower carrier body. A membrane assembly is disposed below the lower carrier body, the membrane assembly including a membrane support and a flexible membrane secured to the membrane support to define a plurality of pressurizable lower chambers. The flexible film has a lower surface that provides a substrate mounting surface. The second flexible seal forms a second pressurizable chamber between the upper carrier body and the lower carrier body. The controller is configured to receive a signal from a sensor arranged to generate data indicative of a pressure in the second pressurizable chamber and configured to control the pressure source to pressurize the second pressurizable chamber based on the signal. In another aspect, a method for chemical mechanical polishing includes loading a substrate into a carrier head having a housing with an upper carrier body and a lower carrier body, and a membrane assembly below the lower carrier body, wherein a space between the lower carrier body and the membrane assembly defines a pressurizable chamber, measuring a distance from a sensor in the lower carrier body to the membrane assembly, and controlling a pressure in the pressurizable chamber based on the measured distance. Controlling the pressure in the pressurizable chamber includes the step of maintaining a consistent total downforce on the membrane assembly as the distance between the sensor and the membrane assembly changes. Advantages may include, but are not limited to, the following. The sensor may detect a change in the distance between the carrier body and the membrane assembly. Such a change in distance may occur even if the chamber pressure is unchanged, for example, due to wear of the retaining ring. The controller may reduce the pressure in the chamber above the membrane assembly to maintain a consistent load on the substrate during multiple polishing operations, thereby improving wafer-to-wafer uniformity. The vertical position of the membrane assembly can be changed without skewing the pressure distribution across the membrane. The details of one or more implementations are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description and drawings, an