Patent ID: 8257545

Claim:
A chemical mechanical polishing pad comprising: a polishing layer having a polishing surface; and, a light stable polymeric endpoint detection window, comprising: a polyurethane reaction product of an aromatic polyamine containing amine moieties and an isocyanate terminated prepolymer polyol containing unreacted —NCO moieties; and, a light stabilizer component comprising at least one of a UV absorber and a hindered amine light stabilizer; wherein the aromatic polyamine and the isocyanate terminated prepolymer polyol are provided at an amine moiety to unreacted —NCO moiety stoichiometric ratio of <95%; wherein the light stable polymeric endpoint detection window exhibits a time dependent strain of ≦0.02% when measured with a constant axial tensile load of 1 kPa at a constant temperature of 60° C. at 100 minutes and an optical double pass transmission of ≧15% at a wavelength of 380 nm for a window thickness of 1.3 mm; and, wherein the polishing surface is adapted for polishing a substrate selected from a magnetic substrate, an optical substrate and a semiconductor substrate.