Polyurethane polishing pad

Abstract

The invention provides a polishing pad suitable for planarizing semiconductor, optical and magnetic substrates. The polishing pad includes a cast polyurethane polymeric material formed from a prepolymer reaction of a polypropylene glycol and a toluene diisocyanate to form an isocyanate-terminated reaction product. The toluene diisocyanate has less than 5 weight percent aliphatic isocyanate; and the isocyanate-terminated reaction product having 5.55 to 5.85 weight percent unreacted NCO. The isocyanate-terminated reaction product being cured with a 4,4′-methylene-bis(3-chloro-2,6-diethylaniline) curative agent. The non-porous cured product having a tan delta of 0.04 to 0.10, a Young's modulus of 140 to 240 MPa and a Shore D hardness of 44 to 56.

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 polypropylene glycol and a toluene diisocyanate to form an isocyanate-terminated reaction product, the toluene diisocyanate having less than 5 weight percent aliphatic isocyanate and the isocyanate-terminated reaction product having 5.55 to 5.85 weight percent unreacted NCO, the isocyanate-terminated reaction product being cured with a 4,4′-methylene-bis(3-chloro-2,6-diethylaniline) curative agent, the cured polymer as measured in a non-porous state having a tan delta of 0.04 to 0.10 from 20 and 100° C. with a torsion fixture (ASTM 5279), a Young's modulus of 140 to 240 MPa at room temperature (ASTM-D412) and a Shore D hardness of 44 to 56 at room temperature (ASTM-D2240). 
     
     
         2 . The polishing pad of  claim 1  wherein the polishing pad is non-porous. 
     
     
         3 . The polishing pad of  claim 1  wherein the isocyanate-terminated reaction product and the 4,4′-methylene-bis(3-chloro-2,6-diethylaniline) has an NH 2  to NCO stoichiometric ratio of 80 to 120 percent. 
     
     
         4 . The polishing pad of  claim 1  wherein the polishing pad includes pores having an average diameter of less than 200 μm. 
     
     
         5 . The polishing pad of  claim 4  wherein the polishing pad includes polymeric microspheres to form pores. 
     
     
         6 . 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 polypropylene glycol and a toluene diisocyanate to form an isocyanate-terminated reaction product, the toluene diisocyanate having less than 5 weight percent aliphatic isocyanate and the isocyanate-terminated reaction product having 5.55 to 5.85 weight percent unreacted NCO, the isocyanate-terminated reaction product being cured with a 4,4′-methylene-bis(3-chloro-2,6-diethylaniline) curative agent, the cured polymer as measured in a non-porous state having a tan delta of 0.04 to 0.10 from 20 and 100° C. with a torsion fixture (ASTM 5279), a Young's modulus of 180 to 240 MPa at room temperature (ASTM-D412) and a Shore D hardness of 46 to 54 at room temperature (ASTM-D2240). 
     
     
         7 . The polishing pad of  claim 6  wherein the polishing pad is non-porous. 
     
     
         8 . The polishing pad of  claim 6  wherein the isocyanate-terminated reaction product and the 4,4′-methylene-bis(3-chloro-2,6-diethylaniline) has an NH 2  to NCO stoichiometric ratio of 100 to 112 percent. 
     
     
         9 . The polishing pad of  claim 6  wherein the polishing pad includes pores having an average diameter of 5 to 100 μm. 
     
     
         10 . The polishing pad of  claim 9  wherein the polishing pad includes polymeric microspheres to form the pores.