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 arranged beneath the lower carrier body, and a flexure. The membrane assembly includes a membrane support and a flexible membrane secured to the membrane support to defining a plurality of pressurizable lower chambers, with the flexible membrane having a lower surface that provides a substrate mounting surface. A flexible seal forms a pressurizable upper chamber between the housing and the membrane support. The flexure connects the membrane support to the housing, and the flexure extends through the pressurizable upper chamber.

What is claimed is: 
     
         1 . A carrier head for chemical mechanical polishing, comprising:
 a housing for attachment to a drive shaft, wherein the housing includes an upper carrier body and a lower carrier body that is 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 arranged beneath the lower carrier body, the membrane assembly including a membrane support and a flexible membrane secured to the membrane support to defining a plurality of pressurizable lower chambers, the flexible membrane having a lower surface that provides 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 . The carrier head of  claim 1 , wherein a first portion of the second pressurizable chamber above the flexure is fluidically connected to a second portion of the second pressurizable chamber below the flexure. 
     
     
         3 . The carrier head of  claim 2 , wherein the flexure includes a plurality of apertures fluidically connecting the first portion of the second pressurizable chamber to the second portion of the second pressurizable chamber. 
     
     
         4 . The carrier head of  claim 2 , wherein the flexure comprises a plurality of arcuate pieces separated by a plurality of gaps. 
     
     
         5 . The carrier head of  claim 2 , wherein the first portion of the second pressurizable chamber and the second portion of the second pressurizable chamber are fluidically connected by a passage through the lower carrier body. 
     
     
         6 . The carrier head of  claim 1 , wherein the first portion of the second pressurizable chamber is an annular chamber surrounding a downward projection of the lower carrier body. 
     
     
         7 . The carrier head of  claim 6 , wherein the second portion of the second pressurizable chamber is a disk-shaped chamber extending across substantially all of the support plate. 
     
     
         8 . The carrier head of  claim 1 , wherein the flexure is arranged horizontally between the lower carrier body and the membrane support. 
     
     
         9 . The carrier head of  claim 8 , wherein the flexure is arranged between an annular upper portion of the membrane support and a downward projection of the lower carrier body. 
     
     
         10 . The carrier head of  claim 1 , wherein the membrane support comprises a plate horizontally spanning above the plurality of pressurizable lower chambers. 
     
     
         11 . The carrier head of  claim 10 , wherein the plate is more rigid than the flexible membrane. 
     
     
         12 . The carrier head of  claim 1 , further comprising a retaining ring connected to the lower carrier body, wherein wear on the retaining ring causes a distance between the membrane support and the lower carrier body to decrease. 
     
     
         13 . The carrier head of  claim 1 , wherein the flexure is sufficiently stiff to horizontally center the membrane assembly within the housing. 
     
     
         14 . The carrier head of  claim 1 , wherein the flexure is sufficiently stiff to vertically center the membrane assembly within the housing. 
     
     
         15 . A carrier head for chemical mechanical polishing, comprising:
 a housing for attachment to a drive shaft,   a membrane assembly arranged beneath the lower carrier body, the membrane assembly including a membrane support and a flexible membrane secured to the membrane support to defining a plurality of pressurizable lower chambers, the flexible membrane having a lower surface that provides 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 . The carrier head of  claim 15 , wherein a first portion of the pressurizable upper chamber above the flexure is fluidically connected to a second portion of the pressurizable upper chamber below the flexure. 
     
     
         17 . The carrier head of  claim 16 , wherein the flexure includes a plurality of apertures fluidically connecting the first portion of the pressurizable upper chamber to the second portion of the pressurizable upper chamber. 
     
     
         18 . The carrier head of  claim 16 , wherein the flexure comprises a plurality of arcuate pieces separated by a plurality of gaps. 
     
     
         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 fluidically connected by a passage through the lower carrier body. 
     
     
         20 . The carrier head of  claim 15 , wherein the first portion of the pressurizable upper chamber is an annular chamber surrounding a downward projection of the lower carrier body. 
     
     
         21 . The carrier head of  claim 20 , wherein the second portion of the pressurizable upper chamber is a disk-shaped chamber extending across substantially all of the support plate.