Polishing pad for wafer polishing device, and apparatus and method for manufacturing same

Abstract

The present invention provides a method for manufacturing a polishing pad, the method comprising: a step for manufacturing a non-woven pad; a polyurethane impregnation step for impregnating the non-woven pad with polyurethane; and a surface polishing step for polishing the surface of the non-woven pad impregnated with polyurethane, wherein the polyurethane impregnation step and the surface polishing step are performed such that the density ratio between the surface layer and the inside of the polishing pad is uniform.

1 . A method of manufacturing a polishing pad for wafer polishing apparatuses, the method comprising:
 a step of manufacturing non-woven fabric;   a polyurethane impregnation step of impregnating the non-woven fabric with polyurethane; and   a surface finishing step of finishing a surface of the non-woven fabric impregnated with the polyurethane, wherein   the polyurethane impregnation step and the surface finishing step are performed such that a density ratio of a surface layer to an interior of a polishing pad is uniform.   
     
     
         2 . The method according to  claim 1 , wherein the polyurethane impregnation step comprises:
 a pretreatment step of pretreating the non-woven fabric;   a first drying step of removing moisture from the non-woven fabric;   an impregnation step of impregnating the non-woven fabric with polyurethane;   a second drying step of drying the polyurethane contained in the non-woven fabric by impregnation; and   a pressing process of pressing the non-woven fabric impregnated with the polyurethane.   
     
     
         3 . The method according to  claim 2 , wherein, in the impregnation step, a polyurethane impregnation process is performed at least twice. 
     
     
         4 . The method according to  claim 3 , wherein the impregnation step comprises:
 a first impregnation process of impregnating the non-woven fabric with hydrophilic polyurethane; and   a second impregnation process of impregnating the non-woven fabric with hydrophobic polyurethane.   
     
     
         5 . The method according to  claim 4 , wherein buffing is performed such that a density ratio of a porous layer containing the polyurethane to a porous layer containing no polyurethane in the surface layer of the polishing pad is 1:1. 
     
     
         6 . The method according to  claim 5 , wherein
 the non-woven fabric has a thickness of 4 mm to 6 mm, and   a thickness of the non-woven fabric removed by the buffing is 2.5 mm to 3.5 mm.   
     
     
         7 . The method according to  claim 6 , wherein the polishing pad has an overall density of 0.44 to 0.55 g/cm 3 . 
     
     
         8 . An apparatus for manufacturing a polishing pad for wafer polishing apparatuses, the apparatus comprising:
 a non-woven fabric manufacturing unit configured to manufacture non-woven fabric;   a polyurethane impregnation unit configured to impregnate the non-woven fabric with polyurethane; and   a surface finishing unit configured to finish a surface of the non-woven fabric impregnated with the polyurethane, wherein   the polyurethane impregnation unit comprises:   a first polyurethane water tank configured to receive hydrophilic polyurethane; and   a second polyurethane water tank configured to receive hydrophobic polyurethane for impregnation.   
     
     
         9 . The apparatus according to  claim 8 , wherein the surface finishing unit performs buffing such that a density ratio of a porous layer containing the polyurethane to a porous layer containing no polyurethane in the surface layer of the polishing pad is 1:1. 
     
     
         10 . The apparatus according to  claim 9 , wherein
 the non-woven fabric has a thickness of 4 mm to 6 mm, and   a thickness of the non-woven fabric removed by the buffing is 2.5 mm to 3.5 mm.