Polishing pad, polishing apparatus, and method for making the polishing pad

Abstract

The present invention relates to a polishing pad comprising a polishing surface. The polishing surface comprises a first polishing area and a second polishing area. The first polishing area comprises a plurality of first foaming holes, and the second polishing area comprises a plurality of second foaming holes, and an average pore diameter of the first foaming holes is less than an average pore diameter of the second foaming holes. The polishing pad according to the present invention uses the polishing areas with the different pore diameters of the holes to avoid unevenly removing the edge and central part of a substrate when polishing, so that a thickness of the substrate becomes uniform.

What is claimed is: 
     
         1 . A method for making a polishing pad, wherein the polishing pad comprises a polishing surface having a foaming resin, and the polishing surface comprises:
 a first polishing area comprising a plurality of first foaming holes; and   a second polishing area comprising a plurality of second foaming holes;   wherein an average pore diameter of the first foaming holes is less than an average pore diameter of the second foaming holes; and   wherein the method comprises:   (a) providing a first polymer composition and a second polymer composition, wherein a viscosity of the first polymer composition is less than a viscosity of the second polymer composition;   (b) forming the second polishing area with the second polymer composition; and   (c) forming the first polishing area with the first polymer composition.   
     
     
         2 . The method according to  claim 1 , comprising:
 (1) providing a first mold and a second mold; wherein the first mold corresponds to the first polishing area, and the second mold corresponds to the second polishing area;   (2) filing a cavity of the second mold with the second polymer composition;   (3) filing a cavity of the first mold with the first polymer composition; and   (4) curing the first polymer composition and the second polymer composition and removing the first mold and the second mold.   
     
     
         3 . The method according to  claim 1 , comprising:
 (i) providing a first mold and a second mold; wherein the first mold corresponds to the first polishing area, and the second mold corresponds to the second polishing area;   (ii) filing a cavity of the second mold with the second polymer composition, and removing the second mold;   (iii) filing a cavity of the first mold with the first polymer composition, and removing the first mold, and curing the first polymer composition and the second polymer composition.   
     
     
         4 . The method according to  claim 1 , comprising:
 (I) providing a first mold, wherein the first mold corresponds to the first polishing area;   (II) forming the second polishing area with the second polymer composition, and curing the second polymer composition; and   (III) placing the cured second polymer composition in a cavity of the first mold, and filing the cavity of the first mold with the first polymer composition, and curing the first polymer composition and removing the first mold.   
     
     
         5 . The method according to  claim 4 , wherein the step (II) comprises:
 (II-1) forming the second polishing area comprising a plurality of second polishing parts with the second polymer composition; and   wherein the step (III) comprises:   (III-1) placing the second polishing parts formed of the cured second polymer composition in a cavity of the first mold.   
     
     
         6 . The method according to  claim 5 , wherein the step (II-1) comprises:
 (II-1-1) providing a second mold;   (II-1-2) filling a cavity of the second mold with the second polymer composition;   (II-1-3) curing the second polymer composition and removing the second mold; and   (II-1-4) skiving the cured second polymer composition into the plurality of second polishing parts.   
     
     
         7 . The method according to  claim 1 , wherein the first polishing area surrounds the second polishing area. 
     
     
         8 . The method according to  claim 1 , wherein the polishing surface further comprises a third polishing area, the third polishing area comprises a plurality of third foaming holes, an average pore diameter of the third foaming holes is greater than the average pore diameter of the second foaming holes, and the step (a) further comprises providing a third polymer composition, a viscosity of the second polymer composition is less than a viscosity of the third polymer composition; and the step (c) further comprises forming the third polishing area with the third polymer composition. 
     
     
         9 . The method according to  claim 8 , wherein the second polishing area surrounds the third polishing area. 
     
     
         10 . The method according to  claim 1 , wherein the first polishing area and the second polishing area are concentric. 
     
     
         11 . The method according to  claim 1 , wherein the second polishing area comprises a plurality of second polishing parts; and the step (b) comprises forming the second polishing parts of the second polishing area with the second polymer composition. 
     
     
         12 . The method according to  claim 1 , wherein the first polishing area comprises a plurality of first polishing parts and the second polishing area comprises a plurality of second polishing parts, the first polishing parts and the second polishing parts extend radially from a center of the polishing pad, and the step (b) comprises forming the second polishing parts of the second polishing area with the second polymer composition, and the step (c) comprises forming the first polishing parts of the first polishing area with the first polymer composition. 
     
     
         13 . The method according to  claim 1 , wherein a porosity of the first polishing area is less than a porosity of the second polishing area.