Systems, apparatus, and methods for an improved polishing head gimbal using a spherical ball bearing

Abstract

Embodiments of the present invention provide systems, apparatus, and methods for an improved polishing head including an upper portion and a lower portion, the lower portion adapted to hold a substrate and to tilt relative to the upper portion, the tilt enabled by a spherical bearing, wherein the lower portion is adapted to tilt while rotating the substrate against a rotating polishing pad so that the lower portion remains flush against the rotating polishing pad while resisting lateral friction force generated by the rotating polishing pad contacting the substrate and pushing the substrate laterally against the lower portion. Numerous additional aspects are disclosed.

The invention claimed is: 
     
         1 . A system for chemical-mechanical planarization comprising:
 a platen supporting a polishing pad and adapted to rotate the polishing pad; and   a polishing head adapted to rotate and including an upper portion and a lower portion, the lower portion adapted to hold a substrate and to tilt relative to the upper portion, the tilt enabled by a spherical bearing,   wherein the lower portion is adapted to tilt while rotating the substrate against the polishing pad so that the lower portion remains flush against the rotating polishing pad while resisting lateral friction force generated by the rotating polishing pad contacting the substrate and pushing the substrate laterally against the lower portion.   
     
     
         2 . The system of  claim 1  wherein the lower portion includes a retaining ring adapted to tilt relative to the upper portion. 
     
     
         3 . The system of  claim 2  wherein the spherical bearing includes an inner portion and an outer ring. 
     
     
         4 . The system of  claim 3  wherein the inner portion is disposed on a shaft coupled to the upper portion and the outer ring is coupled to the lower portion. 
     
     
         5 . The system of  claim 3  wherein the outer ring is coupled to a shaft coupled to the upper portion and the inner portion is coupled to the lower portion. 
     
     
         6 . The system of  claim 3  wherein the retaining ring of the lower portion is adapted to tilt while the substrate is rotated against the polishing pad so that a lower surface of the retaining ring remains flush against the rotating polishing pad. 
     
     
         7 . The system of  claim 6  wherein lateral friction force generated by the rotating polishing pad contacting the substrate is resisted by the retaining ring. 
     
     
         8 . A chemical-mechanical planarization polishing head comprising:
 an upper portion and a lower portion, the lower portion adapted to hold a substrate and to tilt relative to the upper portion, the tilt enabled by a spherical bearing,   wherein the lower portion is adapted to tilt while rotating the substrate against a rotating polishing pad so that the lower portion remains flush against the rotating polishing pad while resisting lateral friction force generated by the rotating polishing pad contacting the substrate and pushing the substrate laterally against the lower portion.   
     
     
         9 . The chemical-mechanical planarization polishing head of  claim 8  wherein the lower portion includes a retaining ring adapted to tilt relative to the upper portion. 
     
     
         10 . The chemical-mechanical planarization polishing head of  claim 9  wherein the spherical bearing includes an inner portion and an outer ring. 
     
     
         11 . The chemical-mechanical planarization polishing head of  claim 10  wherein the inner portion is disposed on a shaft coupled to the upper portion and the outer ring is coupled to the lower portion. 
     
     
         12 . The chemical-mechanical planarization polishing head of  claim 10  wherein the outer ring is coupled to a shaft coupled to the upper portion and the inner portion is coupled to the lower portion. 
     
     
         13 . The chemical-mechanical planarization polishing head of  claim 10  wherein the retaining ring of the lower portion is adapted to tilt while the substrate is rotated against the polishing pad so that a lower surface of the retaining ring remains flush against the rotating polishing pad. 
     
     
         14 . The chemical-mechanical planarization polishing head of  claim 13  wherein lateral friction force generated by the rotating polishing pad contacting the substrate is resisted by the retaining ring. 
     
     
         15 . A method for chemical-mechanical planarization comprising:
 providing a polishing head including an upper portion and a lower portion, the lower portion adapted to hold a substrate and to tilt relative to the upper portion, the tilt enabled by a spherical bearing;   rotating the polishing head while holding the substrate against a moving polishing pad; and   tilting the lower portion while rotating the substrate against the polishing pad so that the lower portion remains flush against the moving polishing pad while resisting lateral friction force generated by the moving polishing pad contacting the substrate and pushing the substrate laterally against the lower portion.   
     
     
         16 . The method of  claim 15  wherein the lower portion includes a retaining ring adapted to tilt relative to the upper portion. 
     
     
         17 . The method of  claim 16  wherein the spherical bearing includes an inner portion and an outer ring. 
     
     
         18 . The method of  claim 17  wherein the inner portion is disposed on a shaft coupled to the upper portion and the outer ring is coupled to the lower portion. 
     
     
         19 . The method of  claim 17  wherein the outer ring is coupled to a shaft coupled to the upper portion and the inner portion is coupled to the lower portion. 
     
     
         20 . The method of  claim 17  wherein the retaining ring of the lower portion is adapted to tilt while the substrate is rotated against the polishing pad so that a lower surface of the retaining ring remains flush against the rotating polishing pad,
 wherein lateral friction force generated by the rotating polishing pad contacting the substrate is resisted by the retaining ring.