Coated compressive subpad for chemical mechanical polishing
Coated compressive subpads for polishing pad stacks and methods of fabricating coated compressive subpads for polishing pad stacks are described. In an example, a polishing pad stack for polishing a substrate includes a polishing pad having a polishing surface and a back surface. The polishing pad stack also includes a compressive subpad with a first surface having a first pressure sensitive adhesive layer coated thereon. The first surface of the compressive subpad is coupled directly to the back surface of the polishing pad by the first pressure sensitive adhesive layer.
1. A subpad for a polishing pad stack, the subpad comprising:
a compressive subpad material having a first surface and a second, opposite, surface;
a first pressure sensitive adhesive layer coated on the first surface of the compressive subpad material, and a first release liner disposed on the first pressure sensitive adhesive layer; and
a second pressure sensitive adhesive layer coated on the second surface of the compressive subpad material, wherein the compressive subpad material is a compressive foam subpad material, and wherein the first and second surfaces of the compressive foam subpad material each have a surface energy approximately in the range of 30-40 dyne/cm 2 , and the first pressure sensitive adhesive layer is in direct contact with at least 90% of the total surface area of the first surface of the compressive subpad material.
2. The subpad of claim 1 , further comprising:
a second release liner disposed on the second pressure sensitive adhesive layer.
3. The subpad of claim 1 , wherein the first pressure sensitive adhesive layer is a removable pressure sensitive adhesive layer, and wherein the second pressure sensitive adhesive layer is a permanent pressure sensitive adhesive layer.
4. The subpad of claim 3 , wherein the permanent pressure sensitive adhesive layer is for coupling to a hack surface of a polishing pad, and wherein the removable pressure sensitive adhesive layer is for coupling the subpad to a platen of a chemical mechanical polishing apparatus.
5. The subpad of claim 1 , wherein the second pressure sensitive adhesive layer has a peel strength of greater than approximately 4.5 pounds per inch at 25 degrees Celsius, and wherein the first pressure sensitive adhesive layer has a peel strength of less than approximately 4 pounds per inch at 25 degrees Celsius.
6. The subpad of claim 1 , wherein the compressive subpad material is a compressive foam subpad material comprising a material selected from the group consisting of an ethylene vinyl acetate closed cell foam material, a polyethylene closed cell foam material, and a polyurethane mostly closed cell foam material.
7. The subpad of claim 1 , wherein the compressive subpad material has a thickness approximately in the range of 10 mils to 40 mils.
8. The subpad of claim 1 , wherein the second pressure sensitive adhesive layer comprises a first material selected from the group consisting of an acrylic material, a rubber, ethylene vinyl acetate, a silicone material, and a block co-polymer, and wherein the first pressure sensitive adhesive layer comprises a second material selected from the group consisting of an acrylic material, a rubber, ethylene vinyl acetate, a silicone material, and a block co-polymer.
9. The subpad of claim 1 , wherein the first surface of the compressive subpad material has a surface roughness of at least 3 microns and has a total surface area, and the first pressure sensitive adhesive layer is in direct contact with at least 95% of the total surface area of the first surface of the compressive subpad material.
10. The subpad of claim 9 , wherein the second surface of the compressive subpad material has a surface roughness of at least 3 microns and has a total surface area, and the second pressure sensitive adhesive layer is in direct contact with at least 90% of the total surface area of the second surface of the compressive subpad material.