Patent ID: 6638145
Filing Date: 2003-10-28
Classification: B24B,H01L

Abstract:
A method of reducing defects on a wafer surface undergoing chemical mechanical planarization, comprising:(a) providing a wafer input/output area including a wet transfer mechanism; (b) providing a first polishing platen; (c) providing a second polishing platen; (d) providing a low pH rinsing station; (e) transferring a first wafer to said first polishing platen using said wet transfer mechanism, said wet transfer mechanism keeping said first wafer wet with a high pH solution; (f) polishing said first wafer on said first platen with a high pH slurry; (g) rinsing said first wafer and said first platen with a high pH solution after step (f); (h) transferring said first wafer to said second platen after step (g); (i) polishing said first wafer on said second platen with a high pH slurry; (j) rinsing said first wafer and said second platen with a high pH solution after step (i); (k) transferring said first wafer to said low pH rinsing station after step (j); (l) rinsing said first wafer with a lower pH solution having a pH lower than said high pH solution at said rinsing station; and wherein the pH at the surface of said first wafer is maintained substantially constant during steps (a)-(k).