Soft and conditionable chemical mechanical polishing pad with window

A chemical mechanical polishing pad, comprising:

• a polishing layer having a polishing surface, a base surface and an average thickness, TP-avg, measured in a direction perpendicular to the polishing surface from the polishing surface to the base surface;
• and,
• an endpoint detection window incorporated into the polishing layer;
• wherein the polishing layer comprises a reaction product of ingredients, comprising:
• a polishing layer prepolymer, wherein the polishing layer prepolymer is selected from the group consisting of isocyanate terminated urethane prepolymers having 2 to 12 wt % unreacted NCO groups;
• and,
• a polishing layer curative system, comprising:
• at least 5 wt % of a polishing layer amine initiated polyol curative having at least one nitrogen atom per molecule and an average of at least three hydroxyl groups per molecule;
• 25 to 95 wt % of a polishing layer high molecular weight polyol curative having a number average molecular weight, MN, of 2,500 to 100,000 and an average of three to ten hydroxyl groups per molecule;
• and,
• 0 to 70 wt % of a polishing layer difunctional curative;
• wherein the endpoint detection window comprises a reaction product of ingredients, comprising:
• a window prepolymer, wherein the window prepolymer is selected from the group consisting of isocyanate terminated urethane prepolymers having 2 to 6.5 wt % unreacted NCO groups;
• and,
• a window curative system, comprising:
• at least 5 wt % of a window difunctional curative;
• at least 5 wt % of a window amine initiated polyol curative having at least one nitrogen atom per molecule and an average of at least three hydroxyl groups per molecule;
• and,
• 25 to 90 wt % of a window high molecular weight polyol curative having a number average molecular weight, MN, of 2,000 to 100,000 and an average of three to ten hydroxyl groups per molecule;
• wherein the polishing layer exhibits a density of ≧0.6 g/cm3;
• a Shore D hardness of 5 to 40;
• an elongation to break of 100 to 450%;
• and, a cut rate of 25 to 150 μm/hr.