Polyurethane polishing pad

Abstract

The polishing pad is suitable for planarizing at least one of semiconductor, optical and magnetic substrates. The polishing pad includes a cast polyurethane polymeric material formed with an isocyanate-terminated reaction product formed from a prepolymer reaction of a prepolymer polyol and a polyfunctional isocyanate. The isocyanate-terminated reaction product has 4.5 to 8.7 weight percent NCO reaction group; and the isocyanate-terminated reaction product is cured with a curative agent selected from the group comprising curative polyamines, curative polyols, curative alcoholamines and mixtures thereof. The polishing pad contains at least 0.1 volume percent filler or porosity.

1 . A polishing pad suitable for planarizing at least one of semiconductor, optical and magnetic substrates, the polishing pad comprising a cast polyurethane polymeric material formed from a prepolymer reaction of a prepolymer polyol and a polyfunctional isocyanate to form an isocyanate-terminated reaction product, the isocyanate-terminated reaction product having 4.5 to 8.7 weight percent NCO reaction group, the isocyanate-terminated reaction product being cured with a curative agent selected from the group comprising curative polyamines, curative polyols, curative alcoholamines and mixtures thereof; and the polishing pad containing at least 0.1 volume percent filler or porosity.  
     
     
         2 . The polishing pad of  claim 1  wherein the prepolymer polyol is selected from the group comprising polytetramethylene ether glycol, polyester polyols, polypropylene ether glycols, polycaprolactone polyols, copolymers thereof and mixtures thereof.  
     
     
         3 . The polishing pad of  claim 2  wherein the curative agent contains curative amines that cure the isocyanate-terminated reaction product and the isocyanate-terminated reaction product has an NH 2  to NCO stoichiometric ratio of 80 to 120 percent.  
     
     
         4 . A polishing pad suitable for planarizing semiconductor substrates, the polishing pad comprising a cast polyurethane polymeric material formed from a prepolymer reaction of a prepolymer polyol selected from the group comprising polytetramethylene ether glycol, polyester polyols, polypropylene ether glycols, copolymers thereof and mixtures therof and a polyfunctional isocyanate to form an isocyanate-terminated reaction product, the isocyanate-terminated reaction product having 4.5 to 8.7 weight percent NCO reaction group, the isocyanate-terminated reaction product being cured with a curative agent with expandable polymeric microspheres, the curative agent selected from the group comprising curative polyamines, curative polyols, curative alcoholamines and mixtures thereof; and the polishing pad containing a porosity of at least 0.1 volume percent.  
     
     
         5 . The polishing pad of  claim 4  wherein the curative agent contains curative amines that cure the isocyanate-terminated reaction product and the isocyanate-terminated reaction product has an NH 2  to NCO stoichiometric ratio of 80 to 120 percent.  
     
     
         6 . The polishing pad of  claim 4  wherein the prepolymer polyol contains polytetramethylene ether glycol, copolymer thereof or a mixture thereof.  
     
     
         7 . The polishing pad of  claim 4  wherein the prepolymer polyol contains polyester polyols, copolymer thereof or a mixture thereof.  
     
     
         8 . The polishing pad of  claim 4  wherein the prepolymer polyol contains polypropylene ether glycols, copolymer thereof or a mixture thereof.  
     
     
         9 . A method of forming a polishing pad suitable for planarizing semiconductor substrates comprising casting polyurethane polymeric material from a prepolymer reaction of a prepolymer polyol and a polyfunctional isocyanate to form an isocyanate-terminated reaction product, the isocyanate-terminated reaction product having 4.5 to 8.7 weight percent NCO reaction group, the isocyanate-terminated reaction product being cured with a curative agent selected from the group comprising curative polyamines, curative polyols, curative alcoholamines and mixtures thereof, and the polishing pad containing at least 0.1 volume percent filler or porosity.  
     
     
         10 . The polishing pad of  claim 1  wherein the polymeric material includes expandable polymeric microspheres and including the step of limiting the exotherm to a temperature below 120° C.