Polyurethane composition with (meth)acrylate end groups useful in the manufacture of polishing pads

A method of polishing the surface of a silicon semi-conductor wafer which method comprises contacting the surface of the silicon semi-conductor wafer with a polishing pad, which polishing pad comprises a polyurethane photopolymer resin which photopolymer resin has been cured by exposure to actinic radiation and wherein said photopolymer resin, prior to said curing, comprises:

• (i) prepolymer;
• (ii) at least one ethylenically unsaturated monomer;
• and (iii) at least one photopolymerization initiator;
• and wherein said prepolymer is the reaction product of X, Y and P and which prepolymer has the following structure:
• Y'-X'.paren open-st.P'-X'.paren close-st..sub.n Y'
• wherein P is selected from the group consisting of polyesters polybutadienes, polyethers and mixtures thereof, X is selected from the group consisting of aromatic diisocyanates, aliphatic diisocyanates, Y is selected from the group consisting of acrylates, methacrylates and mixtures thereof, wherein n is an integer of from 2 to 20, wherein P', X' and Y' are the reaction residues of P, X and Y respectively;
• wherein the polishing pad moves across the surface of the silicon semi-conductor wafer during said contact;
• wherein a slurry of fine particles is present at the interface between the polishing pad and the surface of the silicon semi-conductor wafer, and wherein the surface of the silicon semi-conductor wafer is polished as a result of the motion of the polishing pad across said surface.