Polishing pad and method

Abstract

A polishing pad for polishing a notch on a circumferential edge portion of a wafer has a disk-shaped center pad of a synthetic resin material and holder plates secured to both surfaces of the center pad so as to expose circumferential portions of the center pad. The circumferential portion of the center pad is sectionally shaped so as to be fittingly insertable into the notch. A foamed resin such as foamed urethane is preferably used as the synthetic resin material. The average diameter of air bubbles in the foamed material is in the range of 10 μm-500 μm. The hardness of the foamed material is in the range of 25-95 degrees in the Shore hardness A scale. Such a polishing pad is rotated and the circumferential portion of its center pad is fittingly inserted into and pressed against the notch while slurry is supplied to their contact part through a nozzle to polish the notch.

What is claimed is:  
     
         1 . A disk-shaped polishing pad for polishing a notch formed on a circumferential edge portion of a wafer, said polishing pad comprising: 
 a disk-shaped center pad of a synthetic resin material; and    holder plates secured to both surfaces of said center pad so as to expose circumferential portions of said center pad, said circumferential portion of said center pad being sectionally so shaped as to be fittingly insertable into said notch.    
     
     
         2 . The polishing pad of  claim 1  wherein said synthetic resin material is a foamed resin and said center pad comprises a foamed material.  
     
     
         3 . The polishing pad of  claim 2  wherein said foamed material has air bubbles with an average diameter of 10 μm-500 μm.  
     
     
         4 . The polishing pad of  claim 2  wherein said foamed material has hardness in the range of 25-95 degrees in the Shore hardness A scale.  
     
     
         5 . The polishing pad of  claim 2  wherein said foamed material is foamed urethane.  
     
     
         6 . A method of polishing a notch formed on a circumferential edge portion of a wafer, said method comprising the steps of: 
 preparing a polishing pad comprising a disk-shaped center pad of a synthetic resin material and holder plates secured to both surfaces of said center pad so as to expose circumferential portions of said center pad, said circumferential portion of said center pad being sectionally so shaped as to be fittingly insertable into said notch;    rotating said polishing pad;    inserting said circumferential portion of said center pad fittingly into and pressing said notch; and    supplying slurry having abrading particles dispersed therein to a contact part between said circumferential portion of said center pad and said notch.    
     
     
         7 . The method of  claim 6  wherein said synthetic resin material is a foamed resin and said center pad comprises a foamed material.  
     
     
         8 . The method of  claim 7  wherein said foamed material has air bubbles with an average diameter of 10 μm-50 μm.  
     
     
         9 . The method of  claim 7  wherein said foamed material has hardness in the range of 25-95 degrees in the Shore hardness A scale.  
     
     
         10 . The method of  claim 7  wherein said foamed material is foamed urethane.  
     
     
         11 . The method of  claim 6  further comprising the step of tilting said wafer while said circumferential portion of said center pad is pressed into said notch.  
     
     
         12 . The method of  claim 7  further comprising the step of tilting said wafer while said circumferential portion of said center pad is pressed into said notch.  
     
     
         13 . The method of  claim 8  further comprising the step of tilting said wafer while said circumferential portion of said center pad is pressed into said notch.  
     
     
         14 . The method of  claim 9  further comprising the step of tilting said wafer while said circumferential portion of said center pad is pressed into said notch.  
     
     
         15 . The method of  claim 10  further comprising the step of tilting said wafer while said circumferential portion of said center pad is pressed into said notch.