Polishing pad

Abstract

A polishing pad which comprises a laminate of an abrasive layer with a cushioning layer. The abrasive layer has a Microrubber A hardness of 75 degrees or higher and a thickness of 0.8-3.0 mm. The cushioning layer comprises an unfoamed elastomer and has a thickness of 0.05-1.5 mm. The abrasive layer has at least two kinds of grooves formed in the surface. One of the two kinds of grooves is first grooves and the other is second grooves. The first grooves each has a groove width of 0.5-1.2 mm, and has a groove pitch of 7.5-50 mm. The second grooves each has a groove width of 1.5-3 mm, and has a groove pitch of 20-50 mm. Each of the first grooves and each of the second grooves are open to side edge faces of the abrasive layer.

1 . A polishing pad comprising a laminate of an abrasive layer and a cushioning layer, wherein
 (a) said abrasive layer has a Microdurometer-A hardness of 75 or more and a thickness of 0.8 mm to 3.0 mm,   (b) said cushioning layer is formed of an unfoamed elastomer and has a thickness of 0.05 mm to 1.5 mm,   (c) the surface of said abrasive layer contains at least two groups of grooves, one of said two groups of grooves being referred to as a first groove group, and the other of said two groups of grooves being referred to as a second groove group,   (d) the grooves in said first groove group have a groove width of 0.5 mm to 1.2 mm, and are arranged at intervals of 7.5 mm to 50 mm,   (e) the grooves in said second groove group have a groove width of 1.5 mm to 3 mm, and are arranged at intervals of 20 mm to 50 mm, and   (f) the grooves in said first groove group and the grooves in said second groove group are open at side faces of said abrasive layer.   
     
     
         2 . The polishing pad as claimed in  claim 1 , wherein said Microdurometer-A hardness is 80 or more, and said cushioning layer has a thickness of 0.05 mm to 0.5 mm. 
     
     
         3 . The polishing pad as claimed in  claim 1 , wherein said cushioning layer has a tensile elastic modulus of 15 MPa to 50 MPa. 
     
     
         4 . The polishing pad as claimed in  claim 1 , wherein the shear adhesive strength between said abrasive layer and said cushioning layer is 3,000 gf/(20×20 mm 2 ) or more. 
     
     
         5 . The polishing pad as claimed in  claim 1 , wherein the grooves in said first groove group are arranged in a grid pattern while the grooves in said second groove group are arranged in a grid pattern. 
     
     
         6 . The polishing pad as claimed in  claim 5 , wherein the grooves in said first groove group and those in said second groove group are arranged linearly and parallel to each other. 
     
     
         7 . The polishing pad as claimed in  claim 1 , wherein said abrasive layer has a foam structure containing a polyurethane polymer and a vinyl compound polymer. 
     
     
         8 . The polishing pad as claimed in  claim 7 , wherein said polyurethane polymer and said vinyl compound polymer are in an integrated state. 
     
     
         9 . The polishing pad as claimed in  claim 7 , wherein said vinyl compound polymer accounts for 23 wt % to 66 wt %. 
     
     
         10 . The polishing pad as claimed in  claim 9 , wherein said vinyl compound is in the form of CH 2 ═CR 1 COOR 2  (R 1 : methyl group or ethyl group, R 2 : methyl group, ethyl group, propyl group, or butyl group).