Polishing head and chemical mechanical polishing process using the same

Abstract

A polishing head for a chemical mechanical polishing process is provided. The polishing head includes an inner circle part and an outer circle part. The outer circle part is a ring-like structure that is connected to the inner circle part. The inner circle part and the outer circle part are an integrated structure. There is a level difference between the respective surfaces of the outer circle part and the inner circle part. Further, the surface of the outer circle part is higher than that of the inner circle part.

1 . A polishing head suitable for use in a chemical mechanical polishing process, comprising:
 an inner circle part; and   an outer circle part, wherein the outer circle part is a ring-like structure that is connected to the inner circle part, the inner circle part and the outer circle part are an integrated structure, and there is a level difference between the surface of the outer circle part and the surface of the inner circle part such that the surface of the outer circle part higher than the surface of the inner circle part.   
     
     
         2 . The polishing head of  claim 1 , wherein the level difference is between 5 μm and 35 μm. 
     
     
         3 . The polishing head of  claim 2 , wherein the level difference is 10 μm. 
     
     
         4 . The polishing head of  claim 1 , wherein the inner circle part is a circle and the outer circle part is a ring. 
     
     
         5 . The polishing head of  claim 4 , wherein the ratio of the radius of the circle to the width of the ring is between 2:1 and 5:1. 
     
     
         6 . The polishing head of  claim 5 , wherein the ratio of the radius of the circle to the width of the ring is 3:1. 
     
     
         7 . The polishing head of  claim 1 , wherein the outer circle part is adjacent to the edge of the inner circle part and a junction between the inner circle part and the outer circle part is perpendicular. 
     
     
         8 . The polishing head of  claim 1 , further comprising a connecting ring between the inner circle part and the outer circle part that connects the inner circle part to the outer circle part. 
     
     
         9 . The polishing head of  claim 8 , wherein a surface of the connecting ring is slanted. 
     
     
         10 . A chemical mechanical polishing process, comprising:
 holding a wafer on a polishing pad by a polishing head, wherein the polishing head has a concave-convex configuration.   applying a fixed backside pressure to the polishing head to apply different pressures to the different regions of the wafer through the concave-convex configuration of the polishing head; and   moving the polishing pad and the wafer relatively.   
     
     
         11 . The chemical mechanical polishing process of  claim 10 , wherein the polishing head having the concave-convex configuration comprises a concave part and a convex part, and there is a level difference between the concave part and the convex part. 
     
     
         12 . The chemical mechanical polishing process of  claim 11 , wherein the level difference is between 5 μm and 35 μm. 
     
     
         13 . The chemical mechanical polishing process of  claim 11 , wherein the concave part is an inner circle part, the convex part is an outer circle part, and the inner circle part is connected to the outer circle part. 
     
     
         14 . The chemical mechanical polishing process of  claim 13 , wherein the inner circle part is a circle and the outer circle part is a ring. 
     
     
         15 . The chemical mechanical polishing process of  claim 14 , wherein the ratio of the radius of the circle to the width of the ring is between 2:1 and 5:1. 
     
     
         16 . The chemical mechanical polishing process of  claim 13 , wherein the outer circle part is adjacent to the edge of the inner circle part and a junction between the inner circle part and the outer circle part is perpendicular. 
     
     
         17 . The chemical mechanical polishing process of  claim 13 , further comprising a connecting ring between the inner circle part and the outer circle part that connects the inner circle part to the outer circle part. 
     
     
         18 . The chemical mechanical polishing process of  claim 17 , wherein a surface of the connecting ring is slanted.