POLISHING PAD HAVING FILLED NON-POROUS SUB-PAD
A polishing pad for chemical mechanical polishing comprises a polishing layer and a subpad. The polishing layer has a polishing surface and a polishing layer interface surface opposite the polishing surface and comprises a polishing material. The subpad layer has a subpad interface surface adjacent to the polishing layer interface surface and a bottom surface opposite the subpad interface surface, and comprises a subpad material. The subpad layer has an average elastic modulus under compression at pressures of from 24 to less than 48 kPa of 1 to 5 MPa and an average elastic modulus under compression at pressures of 48 to 76 kPa of 5 to 20 MPa and a true strain of less than or equal to 10% over compression pressures of up to 1.2 MPa.
1 . A polishing pad for chemical mechanical polishing comprising:
a polishing layer having a polishing surface and a polishing layer interface surface opposite the polishing surface, the polishing layer comprising a polishing material,
a subpad layer having a subpad interface surface adjacent to the polishing layer interface surface and a bottom surface opposite the subpad interface surface, the subpad layer comprising a subpad material,
wherein the subpad layer has an average elastic modulus under compression at pressures of from 24 to less than 48 kPa of 1 to 5 MPa and an average elastic modulus under compression at pressures of 48 to 76 kPa of 5 to 20 MPa and a true strain of less than or equal to 10% over compression pressures of up to 1.2 MPa.
2 . The polishing pad of claim 1 wherein the subpad layer is non-porous.
3 . The polishing pad of claim 2 wherein the subpad layer comprises a particulate filler in a polymeric matrix material.
4 . The polishing pad of claim 3 wherein the particulate filler is an inorganic material.
5 . The polishing pad of claim 3 wherein the particulate filler is a thermally conductive material.
6 . The polishing pad of claim 3 wherein the particulate filler is present in an amount of 40 to 90 weight percent based on total weight of particulate filler and polymeric matrix material.
7 . The polishing pad of claim 3 wherein the polymeric matrix material comprises a silicone composition.
8 . The polishing pad of claim 7 wherein the silicone composition comprises 2 to 80 weight percent silicone adhesive and 20 to 98 weight percent silicone rubber based on total weight of the silicone composition.
9 . The polishing pad of claim 3 wherein the subpad material is provided on a woven or non-woven material scaffold.
10 . The polishing pad of claim 5 wherein the particulate filler is boron nitride.