Low density polishing pad
Low density polishing pads and methods of fabricating low density polishing pads are described. In an example, a polishing pad for polishing a substrate includes a polishing body having a density approximately in the range of 0.4-0.55 g/cc. The polishing body includes a thermoset polyurethane material and a plurality of closed cell pores dispersed in the thermoset polyurethane material. Each of the plurality of closed cell pores has a shell composed of an acrylic co-polymer.
1. A polishing pad for polishing a substrate, the polishing pad comprising:
a polishing body having a density approximately in the range of 0.4-0.55 g/cc and comprising:
a thermoset polyurethane material; and
a plurality of closed cell pores dispersed in the thermoset polyurethane material, each of the plurality of closed cell pores having a shell comprising an acrylic co-polymer, wherein the plurality of closed cell pores has a multi-modal distribution of diameters, and wherein the plurality of closed cell pores provides a total pore volume in the thermoset polyurethane material approximately in the range of 50-60% of the total volume of the thermoset polyurethane material.
2. The polishing pad of claim 1 , wherein the polishing body has a density approximately in the range of 0.44-0.52 g/cc.
3. The polishing pad of claim 1 , wherein the polishing body is a homogeneous polishing body.
4. The polishing pad of claim 1 , wherein the polishing body further comprises:
a first, grooved surface; and
a second, flat, surface opposite the first surface.
5. The polishing pad of claim 1 , wherein each of the plurality of closed cell pores is essentially spherical.
6. The polishing pad of claim 1 , wherein the polishing body is a molded polishing body.
7. The polishing pad of claim 1 , wherein the polishing body further comprises:
an opacifying filler distributed approximately evenly throughout the polishing body.
8. The polishing pad of claim 1 , further comprising:
a support layer disposed on a back surface of the polishing body.
9. The polishing pad of claim 1 , further comprising:
a detection region disposed in a back surface of the polishing body.
10. The polishing pad of claim 1 , further comprising:
a sub pad disposed on a back surface of the polishing body.
11. The polishing pad of claim 1 , further comprising:
a local area transparency (LAT) region disposed in, and covalently bonded with, the polishing body.