Patent ID: 9597769
Date: 2017-03-21
CPC Classifications: B24B,B24D

Claim:
1. A polishing pad for polishing a substrate, the polishing pad comprising: a foundation layer having a global top surface and a transparent region; a polishing surface layer attached to the global top surface of the foundation layer, the polishing surface layer having a polishing surface and a back surface; and an aperture disposed in the polishing pad from the back surface through to the polishing surface of the polishing surface layer and aligned with the transparent region of the foundation layer, wherein the transparent region of the foundation layer provides an impermeable seal for the aperture at the back surface of the polishing surface layer, wherein the aperture is disposed over a trench formed in but not through the transparent region of the foundation layer, and wherein the trench comprises side surfaces and a bottom surface that acts as a slurry deflection feature comprising the bottom surface as a single planar surface with an uppermost height at a first side of the trench sloped down to a lowermost height at a second side of the trench.