Homogeneous polishing pad for eddy current end-point detection
View Patent ↗Homogeneous polishing pads for polishing semiconductor substrates using eddy current end-point detection are described. Methods of fabricating homogeneous polishing pads for polishing semiconductor substrates using eddy current end-point detection are also described.
1. A method of fabricating a polishing pad for polishing a semiconductor substrate, the method comprising:
forming a polishing pad precursor mixture in a formation mold;
positioning a lid of the formation mold into the polishing pad precursor mixture, the lid having a pattern of grooves disposed thereon, the pattern of grooves having an interrupted region;
curing the polishing pad precursor mixture to provide a molded homogeneous polishing body comprising a polishing surface and a back surface, wherein the pattern of grooves from the lid is disposed in the polishing surface, the pattern of grooves having a bottom depth; and
providing an end-point detection region in the molded homogeneous polishing body, the end-point detection region having a first surface oriented with the polishing surface and a second surface oriented with the back surface, at least a portion of the first surface co-planar with the bottom depth of the pattern of grooves and including the interrupted region of the pattern of grooves, and the second surface recessed into the molded homogeneous polishing body relative to the back surface, wherein the first surface of the end-point detection region comprises a second pattern of grooves having a depth essentially co-planar with the bottom depth of the pattern of grooves disposed in the polishing surface of the molded homogeneous polishing body.
2. The method of claim 1 , wherein providing the end-point detection region is performed by routing out a portion of the molded homogeneous polishing body.
3. The method of claim 1 , wherein providing the end-point detection region is performed by removing a sacrificial layer embedded in the molded homogeneous polishing body.
4. The method of claim 1 , wherein individual grooves of both the pattern of grooves and the second pattern of grooves are spaced apart by a width, and wherein the second pattern of grooves is offset from the first pattern of grooves by a distance greater than the width.
5. The method of claim 1 , wherein the molded homogeneous polishing body comprises a thermoset, closed cell polyurethane material.
6. The method of claim 1 , wherein the molded homogeneous polishing body, including the end-point detection region, is opaque.