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 polishing pad for polishing a semiconductor substrate, the polishing pad comprising:
a molded homogeneous polishing body comprising a front side having a polishing surface, and comprising a back side having a back surface;
a pattern of grooves disposed in the polishing surface, the pattern of grooves having a bottom depth; and
an end-point detection region formed in the molded homogeneous polishing body, the end-point detection region having a first surface at the front side of the molded homogeneous polishing body, and having a second surface at the back side of the molded homogeneous polishing body, at least a portion of the first surface being co-planar with the bottom depth of the pattern of grooves and interrupting the pattern of grooves, and the second surface being recessed into the molded homogeneous polishing body relative to the back surface.
2. The polishing pad of claim 1 , wherein the entire first surface of the end-point detection region is essentially co-planar with the bottom depth of the pattern of grooves.
3. The polishing pad of claim 1 , 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.
4. The polishing pad of claim 3 , 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 pattern of grooves by a distance greater than the width.
5. The polishing pad of claim 1 , wherein the molded homogeneous polishing body comprises a thermoset, closed cell polyurethane material.
6. The polishing pad of claim 1 , wherein the molded homogeneous polishing body, including the end-point detection region, is opaque.
7. A method of fabricating a polishing pad for polishing a semiconductor substrate, the method comprising:
forming, by a molding process, a polishing pad comprising:
a homogeneous polishing body comprising a front side having a polishing surface, and comprising a back side having a back surface;
a pattern of grooves disposed in the polishing surface, the pattern of grooves having a bottom depth; and
an end-point detection region formed in the molded homogeneous polishing body, the end-point detection region having a first surface at the front side of the molded homogeneous polishing body, and having a second surface at the back side of the molded homogeneous polishing body, at least a portion of the first surface being co-planar with the bottom depth of the pattern of grooves and interrupting the pattern of grooves, and the second surface being recessed into the molded homogeneous polishing body relative to the back surface.
8. The method of claim 7 , wherein the entire first surface of the end-point detection region is essentially co-planar with the bottom depth of the pattern of grooves.
9. The method of claim 7 , 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.
10. The method of claim 9 , 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 pattern of grooves by a distance greater than the width.
11. The method of claim 7 , wherein the molded homogeneous polishing body comprises a thermoset, closed cell polyurethane material.
12. The method of claim 7 , wherein the molded homogeneous polishing body, including the end-point detection region, is opaque.