Patent ID: 8864859

Claim:
An article comprising a unitary chemical mechanical polishing pad formed of a thermosetting polymer, wherein said pad contains hard polymeric domains and soft polymeric domains in a polishing surface of said pad, wherein said polymer contains hard segments and soft segments, the hard segments forming the hard polymeric domains and the soft segments forming said soft polymeric domains upon curing, wherein said polymer comprises poly(urethaneurea), wherein said pad contains a boundary at the polishing surface between first and second regions of the polishing surface, wherein said first and second regions of the polishing surface are first and second polymeric regions, the first and second regions each including both said hard and said soft domains, and wherein said first region has a porosity property for pores consisting of hollow microelements, the porosity property having a value different from a value for said porosity property in said second region, the porosity property selected from the group consisting of pore size and pore distribution.