摘要 |
A preconditioning mechanism for preconditioning a polishing pad is described. The preconditioning mechanism includes an arm capable of being disposed over the polishing pad and a head section located on a distal end of the arm and rotatable about a central axis. Furthermore, the head section includes at least two heads oriented about the central axis and have surfaces for either conditioning or preconditioning the polishing pad, whereby rotation of the head section about the central axis by defined amounts presents at least two heads to the polishing pad so that different of the two heads can engage the polishing pad for conditioning or preconditioning depending upon how far rotation has proceeded.
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