A polishing pad has an excellent polishing rate and is superior in longevity without generating center slow. A method of manufacturing a semiconductor device with the polishing pad is also provided. The polishing pad has a polishing layer consisting of a polyurethane foam having fine cells, wherein a high-molecular-weight polyol component that is a starting component of the polyurethane foam contains a hydrophobic high-molecular-weight polyol A having a number-average molecular weight of 550 to 800 and a hydrophobic high-molecular-weight polyol B having a number-average molecular weight of 950 to 1300 in an A/B ratio of from 10/90 to 50/50 by weight.
1. A polishing pad having a polishing layer consisting of a polyurethane foam having cells with an average cell diameter of 70 μm or less, wherein a high-molecular-weight polyol component that is a starting component of the polyurethane foam contains a hydrophobic high-molecular-weight polyol A having a number-average molecular weight of 550 to 800 and a hydrophobic high-molecular-weight polyol B having a number-average molecular weight of 950 to 1300 in an A/B ratio of from 10/90 to 50/50 by weight,
the polyurethane foam of the polishing layer being a cured product produced by reacting, with a chain extender, an isocyanate-terminated prepolymer A containing the polyol A and an isocyanate component, and an isocyanate-terminated prepolymer B containing the polyol B and an isocyanate component.
2. The polishing pad according to claim 1 , wherein the polyurethane foam is a cured product produced by reacting, with a chain extender, an isocyanate-terminated prepolymer containing a polyol component and an isocyanate component.
3. The polishing pad according to claim 1 , wherein the hydrophobic high-molecular-weight polyols A and B are polytetramethylene glycol.
4. The polishing pad according to claim 2 , wherein the chain extender is an aromatic diamine.
5. The polishing pad according to claim 4 , wherein the aromatic diamine is a non-halogen aromatic diamine.
6. The polishing pad according to claim 1 , wherein the polyurethane foam contains 0.05 wt % to less than 5 wt % hydroxyl group-free silicon-based nonionic surfactant.
7. The polishing pad according to claim 1 , wherein the specific gravity of the polyurethane foam is 0.7 to 0.88.
8. The polishing pad according to claim 1 , wherein the Asker D hardness of the polyurethane foam is 45° to 60° .
9. The polishing pad according to claim 1 , wherein the tensile strength of the polyurethane foam is 15 MPa to 25 MPa.
10. The polishing pad according to claim 1 , wherein the tensile elongation at break of the polyurethane foam is 50% to 150%.
11. A method of producing a semiconductor device, which comprises a step of polishing the surface of a semiconductor wafer with the polishing pad according to claim 1 .