Patent ID: 9555518
Date: 2017-01-31
CPC Classifications: B24B

Claim:
1. A method of fabricating a polishing pad for polishing a semiconductor substrate, the method comprising: mixing a pre-polymer and a curative to form a mixture in a formation mold; and curing the mixture to provide a molded homogeneous polishing body comprising a thermoset polyurethane material and a plurality of closed cell pores disposed in the thermoset polyurethane material, the plurality of closed cell pores having a multi-modal distribution of diameters, wherein the molded homogeneous polishing body further comprises a first, grooved surface and a second, flat surface opposite the first surface, and wherein curing the mixture comprises grading the multi-modal distribution of diameters throughout the thermoset polyurethane material with a gradient from the first, grooved surface to the second, flat surface, wherein the mixing further comprises adding a plurality of porogens to the pre-polymer and the curative to provide a first portion of the closed cell pores, each having a physical shell, and wherein the mixing further comprises injecting a gas into the pre-polymer and the curative, or into a product formed there from, to provide a second portion of the closed cell pores, each having no physical shell.