Patent ID: 8075372

Claim:
A polishing pad for chemical-mechanical polishing comprising a pad body comprising a porous polymeric material, the pad body having at least one first region and at least one second region adjacent to the at least one first region, the pad body including pores having a first void volume in the at least one first region and pores having a second void volume in the at least one second region, wherein the pores in the at least one first region have a void volume of about 5% to about 50%, and the pores in the at least one second region have a void volume of about 20% to about 80%, and wherein the at least one first region or the at least one second region comprises about 5% or more closed cells, and wherein: (a) the first void volume and second void volume are non-zero, (b) the first void volume is less than the second void volume, (c) the porous polymeric material in the at least one first region and the at least one second region has the same polymer formulation, (d) the pad body does not have a structurally distinct boundary between the at least one first region and the at least one second region, and (e) the pores in the at least one first region or the at least second region have a multi-modal pore size distribution, wherein the multi-modal distribution has about 20 or fewer pore size maxima.