Membrane for applying pressure to pad in chemical mechanical polishing

Abstract

A chemical mechanical polishing system includes a chuck assembly that has a chuck to hold a substrate, a motor to rotate the chuck about a first axis, and a pad carrier assembly. The pad carrier assembly includes a support that is movably along a radial direction relative to the first axis, a lateral actuator coupled the support to cause the support to move along the radial direction, a support arm extending from the support over the chuck, a pad carrier suspended from the support arm, the pad carrier configured to receive and hold a polishing pad, and a flexible membrane secured to the support arm to form a plurality of individually pressurizable chambers between the pad carrier and the support arm such that variation of a pressure difference between the chambers adjusts a radial distribution of pressure on the pad carrier.

1 . A chemical mechanical polishing system, comprising:
 a chuck assembly comprising a chuck configured to hold a substrate during a polishing operation;   a motor configured to rotate the chuck about a first axis; and   a pad carrier assembly including
 a support that is moveable along a radial direction relative to the first axis, 
 a lateral actuator coupled to the support and configured to cause the support to move along the radial direction, 
 a support arm extending from the support over the chuck, 
 a pad carrier suspended from the support arm, the pad carrier configured to receive and hold a polishing pad, and 
 a flexible membrane secured to the support arm to form a plurality of individually pressurizable chambers between the pad carrier and the support arm such that variation of a pressure difference between the chambers adjusts a radial distribution of pressure on the pad carrier. 
   
     
     
         2 . The system of  claim 1 , wherein the pad carrier is an arcuate body, and the plurality of chambers are arcuate chambers. 
     
     
         3 . The system of  claim 1 , wherein the plurality of chambers includes an inner chamber closer to the first axis, a central chamber, and an outer chamber farther from the first axis. 
     
     
         4 . The system of  claim 1 , wherein the flexible membrane comprises a substantially planar bottom portion forming an arcuate area. 
     
     
         5 . The system of  claim 4 , wherein the flexible membrane comprises an inner wall extending upward from an inner edge of the bottom portion and an outer wall extending upward from an outer edge of the bottom portion. 
     
     
         6 . The system of  claim 5 , wherein the flexible membrane comprises an upper inner flap extending inwardly from the inner wall and having an end secured to the support arm and upper outer flap extending outwardly from the outer wall and having an end secured to the support arm. 
     
     
         7 . The system of  claim 6 , wherein the flexible membrane comprises a lower inner flap extending inwardly from the inner wall at a location between the upper inner flap and the bottom portion and having an end secured to the support arm, and wherein a volume between the and the lower inner flap and the upper inner flap provides an inner chamber. 
     
     
         8 . The system of  claim 7 , wherein a volume between the inner wall and outer wall and above the upper inner flap and upper outer flap provides a central chamber. 
     
     
         9 . The system of  claim 8 , wherein the membrane is configured such that a pressure differential between the inner chamber and the central chamber adjusts a vertical position of the inner wall. 
     
     
         10 . The system of  claim 7 , wherein the flexible membrane comprises a lower outer flap extending outwardly from the outer wall at a location between the upper outer flap and the bottom portion and having an end secured to the support arm, and wherein a volume between the lower outer flap and the upper outer flap provides an outer chamber. 
     
     
         11 . The system of  claim 8 , wherein a volume between the inner wall and outer wall and above the upper inner flap and upper outer flap provides a central chamber. 
     
     
         12 . The system of  claim 9 , wherein the membrane is configured such that a pressure differential between the inner chamber and the central chamber adjusts a vertical position of the inner wall and a pressure differential between an outer chamber and the central chamber adjusts a vertical position of the outer wall. 
     
     
         13 . The system of  claim 6 , wherein the flexible membrane comprises a lower outer flap extending outwardly from the outer wall at a location between the upper outer flap and the bottom portion and having an end secured to the support arm, and wherein a volume between the lower outer flap and the upper outer flap provides an outer chamber. 
     
     
         14 . The system of  claim 13 , wherein a volume between the inner wall and outer wall and above the upper inner flap and upper outer flap provides a central chamber. 
     
     
         15 . The system of  claim 14 , wherein the membrane is configured such that a pressure differential between the outer chamber and the central chamber adjusts a vertical position of the outer wall. 
     
     
         16 . A chemical mechanical polishing system, comprising:
 a chuck assembly comprising a chuck configured to hold a substrate during a polishing operation;   a motor configured to rotate the chuck about a first axis; and   a pad carrier assembly including
 a support arm extending from the support over the chuck, 
 a pad carrier suspended from the support arm, the pad carrier configured to receive and hold a polishing pad, and 
 a flexible membrane secured to the support arm to form a plurality of individually pressurizable annular chambers between the pad carrier and the support arm such that variation of a pressure difference between the chambers adjusts a radial distribution of pressure on the pad carrier.