Polishing pad and method of making the same

Abstract

The disclosure is directed to polishing pads with porous polishing layers, methods of making such polishing pads, and methods of using such pads in a polishing process. The polishing pad includes a compliant layer having first and second opposing sides and a porous polishing layer disposed on the first side of the compliant layer. The porous polishing layer includes a crosslinked network comprising a thermally cured component and a radiation cured component, wherein the radiation cured component and the thermally cured component are covalently bonded in the crosslinked network. The porous polishing layer also includes polymer particles dispersed within the crosslinked network, wherein the polymer particles comprise at least one of thermoplastic polymers or thermoset polymers. The porous polishing layer typically also includes closed cell pores dispersed within the crosslinked network.

1 . A polishing pad comprising:
 a compliant layer having first and second opposing sides; and   a porous polishing layer disposed on the first side of the compliant layer, the porous polishing layer comprising:
 a crosslinked network comprising a thermally cured component and a radiation cured component, wherein the radiation cured component and the thermally cured component are covalently bonded in the crosslinked network; 
 polymer particles dispersed within the crosslinked network; and 
 closed cell pores dispersed within the crosslinked network. 
   
     
     
         2 . The polishing pad according to  claim 1 , further comprising a support layer interposed between the compliant layer and the porous polishing layer. 
     
     
         3 . The polishing pad according to  claim 1 , wherein the thermally cured component comprises at least one of a polyurethane or a polyepoxide, and wherein the radiation cured component comprises at least one of a polyacrylate, a polymethacrylate, a poly(vinyl ether), a polyvinyl, or a polyepoxide. 
     
     
         4 . The polishing pad according to  claim 1  or  2 , wherein thermally cured component and the polymer particles each independently comprise a polyurethane, and wherein the radiation cured component comprises at least one of a polyacrylate or a polymethacrylate. 
     
     
         5 . The polishing pad according  claim 1 , wherein the polymer particles are covalently bonded to at least one of the thermally cured component or the radiation cured component in the crosslinked network. 
     
     
         6 . The polishing pad according to  claim 4 , wherein the polyacrylate or polymethacrylate is covalently bonded to the thermally cured component through urethane or urea linking groups. 
     
     
         7 . A method of making a polishing pad, the method comprising:
 providing a composition comprising a thermally curable resin composition, a radiation curable resin composition, and polymer particles;   forming pores in the composition;   positioning the composition on a support layer; and   forming a porous polishing layer on the support layer by exposing the composition to radiation to at least partially cure the radiation curable resin composition and heating the composition to at least partially cure the thermally curable resin composition.   
     
     
         8 . The method according to  claim 7 , further comprising adhesively bonding a compliant layer to a surface of the support layer opposite the porous polishing layer. 
     
     
         9 . The method according to  claim 7 , wherein the thermally curable resin composition comprises a first resin having at least two isocyanate groups or at least two epoxide groups and at least a second resin having at least two hydroxyl, amino, carboxy, or mercaptan groups, and wherein the radiation curable composition comprises at least two acrylate, methacrylate, vinyl, or epoxide groups. 
     
     
         10 . The method according to  claim 9 , wherein the first resin has at least two isocyanate groups, wherein the second resin has at least two hydroxyl groups or at least two amino groups, wherein the radiation curable composition comprises at least two acrylate or methacrylate groups, and wherein the radiation curable composition further comprises at least one of an isocyanate group or a hydroxyl group. 
     
     
         11 . The method according to  claim 7 , wherein the composition further comprises a surfactant. 
     
     
         12 . The method according to  claim 7 , wherein the pores are closed cell pores. 
     
     
         13 . The polishing pad according to  claim 1 , wherein the porous polishing layer has a hardness of at least 40 Shore D as measured by Test Method 2. 
     
     
         14 . The polishing pad according to  claim 1 , wherein the polymer particles have at least one of the following features:
 an average particle size in a range from 5 micrometers to 500 micrometers,   the polymer particles are present up to 20 percent by weight, based on the total weight of the porous polishing layer; or   the polymer particles are substantially spherical.   
     
     
         15 . (canceled) 
     
     
         16 . The polishing pad according to  claim 1 , wherein the polymeric particles are fibers. 
     
     
         17 . (canceled) 
     
     
         18 . The polishing pad according to  claim 1 , wherein the pores have at least one of the following features:
 a pore size non-uniformity up to 75 percent, or   an average pore size in a range from 5 microns to 100 microns.   
     
     
         19 . (canceled) 
     
     
         20 . The polishing pad according to  claim 2 , wherein the polishing layer comprises separated polishing elements protruding from the support layer or the compliant layer. 
     
     
         21 . The polishing pad according to  claim 2 , wherein at least one of the support layer or compliant layer comprises at least one of silicone, natural rubber, styrene-butadiene rubber, neoprene, polyolefin, or polyurethane. 
     
     
         22 . The polishing pad according to  claim 1 , wherein at least a portion of the polishing pad is transparent. 
     
     
         23 . A method of polishing comprising:
 contacting a surface of a substrate with the porous polishing layer of the polishing pad according to  claim 1 ; and   relatively moving the polishing pad with respect to the substrate to abrade the surface of the substrate.