Patent ID: 7708621

Claim:
A polishing apparatus comprising: a head that holds a semiconductor wafer; a polishing pad that polishes a surface to be polished of the semiconductor wafer held by the head; a disk-shaped dresser that reconditions the polishing pad by cutting the polishing pad; and a dresser oscillator that supports at least two said disk-shaped dressers so that the disk-shaped dressers can rotate on their own axes, and that simultaneously oscillates the disk-shaped dressers on the polishing pad, wherein the dresser oscillator separately supports each of the disk-shaped dressers and has a dresser position controller that controls the position of each of the disk-shaped dressers so that oscillations of each of the disk-shaped dressers are in synchronization with each other, and wherein a rotation axis of each of the disk-shaped dressers is rotatably supported in a dresser supporting plate, the dresser supporting plate has another rotation axis that differs from the rotation axis of each of the disk-shaped dressers, and the dresser supporting plate rotates on its own rotation axis.