Polishing pad and method of producing the same

A method of polishing a semiconductor wafer, which comprises:

• providing a semiconductor wafer polishing pad having a polishing layer constituted by resin foam of closed-cell type, wherein the number of closed cells in the polishing layer is 200 to 600 per mm2 and the average diameter of the closed cells is 30 to 60 μm;
• and
• rotating the polishing pad and simultaneously positioning the polishing pad to abut on a semiconductor wafer while supplying an abrasive between the polishing layer and the semiconductor wafer;
• wherein
• a resin constituting the resin foam consists of a polyurethane resin produced by mixing a first component containing an isocyanate group-containing compound with a second component containing an active hydrogen group-containing compound followed by hardening the mixture by heating, said mixture containing a curing agent and a silicone-based surfactant
• the resin foam has a hardness of 45 or more and less than 65 as measured using a D-type rubber hardness meter, and
• the closed cells solely contain gas selected from the group consisting of nitrogen, oxygen, a rare gas, dry air, and a mixed gas of the foregoing.