Variable abrasive polishing pad for mechanical and chemical-mechanical planarization

Abstract

An abrasive polishing pad for planarizing a substrate. In one embodiment, the abrasive polishing pad has a planarizing surface with a first planarizing region and a second planarizing region. The first planarizing region has a first abrasiveness and the second planarizing region has a second abrasiveness different than the first abrasiveness of the first region. The polishing pad preferably has a plurality of abrasive elements at the planarizing surface in at least one of the first or second planarizing regions. The abrasive elements may be abrasive particles fixedly suspended in a suspension medium, contact/non-contact regions on the pad, or other elements that mechanically remove material from the wafer. In operation of a preferred embodiment, the lesser abrasive of the first and second planarizing regions contacts a first area of the wafer where the relative velocity between the wafer and the polishing pad is relatively high, and the more abrasive of the first and second planarizing regions contacts a second area of the wafer where the relative velocity between the wafer and the polishing pad is relatively low. The different abrasivenesses of the first and second planarizing regions compensate for variations in relative velocities across the face of the wafer to more uniformly planarize the wafer.