Method of manufacturing chemical mechanical polishing layers having a window

A method of forming a polishing layer for a chemical mechanical polishing pad, comprising:

• providing a mold, having a mold base and a surrounding wall attached to the mold base;
• providing a liner with a top surface, a bottom surface and an average thickness of 2 to 10 cm;
• providing a liner adhesive;
• providing a window block;
• providing a window adhesive;
• providing a curable material comprising a liquid prepolymer;
• providing a nozzle, having a nozzle opening;
• providing a skiver blade with a cutting edge;
• providing a strop;
• providing a stropping compound;
• bonding the bottom surface of the liner to the mold base using the liner adhesive, wherein the top surface of the liner and the surrounding wall define a mold cavity;
• bonding the window block to the top surface of the liner using the window adhesive;
• charging the curable material through the nozzle opening to the mold cavity during a charging period, CP;
• allowing the curable material in the mold cavity to cure into a cake;
• separating the surrounding wall from the mold base and the cake;
• applying the stropping compound to the cutting edge;
• stropping the skiver blade with the strop;
• and,
• slicing the cake into multiple chemical mechanical polishing layers, wherein each polishing layer has an integral window.