Polishing pad with oriented pore structure
The invention provides a polishing pad for chemical-mechanical polishing comprising a body, a polishing surface, and a plurality of elongated pores, wherein about 10% or more of the elongated pores have an aspect ratio of about 3:1 or greater and are substantially oriented in a direction that is coplanar with the polishing surface. The invention further provides a method of polishing a substrate.
1. A polishing pad for chemical-mechanical polishing comprising a body, a polishing surface, and a plurality of pores, wherein about 10% or more of the pores are elongated pores having an aspect ratio of about 3:1 or greater that are substantially oriented in a direction that is coplanar with the polishing surface, and wherein any remaining pores are secondary pores having an aspect ratio of about 2:1 or less that are not substantially oriented in a direction that is coplanar with the polishing surface.
2. The polishing pad of claim 1 , wherein about 10% or more of the pores are elongated pores having an aspect ratio of about 5:1 or greater.
3. The polishing pad of claim 1 , wherein about 50% or more of the pores are elongated pores having an aspect ratio of about 3:1 or greater.
4. The polishing pad of claim 1 , wherein the body of the polishing pad has a thickness defined by the distance between the polishing surface and a bottom surface of the polishing pad, and wherein the elongated pores are present in the upper about 20% or more of the thickness of the body of the polishing pad.
5. The polishing pad of claim 1 , wherein the polishing pad further comprises a polymer resin.
6. The polishing pad of claim 5 , wherein the polymer resin is a thermoplastic elastomeric polymer resin selected from the group consisting of polyurethanes, polyvinylalcohols, polyvinylacetates, polycarbonates, polyacrylic acids, polyacrylamides, polyolefins, polyethylenes, polypropylenes, nylons, fluorocarbons, polyesters, polyethers, polyamides, polyimides, polytetrafluoroethylenes, polyethcretherketones, copolymers thereof, and mixtures thereof.
7. The polishing pad of claim 6 , wherein the thermoplastic elastomeric polymer resin is a polyurethane resin.
8. The polishing pad of claim 5 , wherein the polymer resin has a viscosity of about 700 Pa-s or greater at a shear rate of about 18.6 s−1 and a temperature of about 210° C.
9. The polishing pad of claim 5 , wherein the polishing pad has a density that is about 70% or more of the maximum theoretical density of the polymer resin.
10. The polishing pad of claim 1 , wherein the polishing pad has a void volume of about 2% or more.
11. The polishing pad of claim 10 , wherein the polishing pad has a void volume of about 5% or more.
12. The polishing pad of claim 11 , wherein the polishing pad has a void volume of about 30% or less.
13. The polishing pad of claim 1 , wherein the polishing pad has a void volume of about 50% or less.
14. The polishing pad of claim 1 , wherein the polishing pad is a polishing layer and is mated to a polishing subpad.
15. The polishing pad of claim 1 , further comprising one or more regions having a light transmittance of about 10% or more at a wavelength of about 200 nm to about 10,000 nm.
16. The polishing pad of claim 1 , wherein the polishing surface has a surface roughness of about 1 to about 3 micron Ra.