Patent ID: 8694144

Claim:
A computer-implemented method of polishing, comprising: measuring a first pre-polish thickness of a layer of a first substrate at an in-line metrology station; measuring a second pre-polish thickness of a layer of a second substrate at the in-line metrology station; simultaneously contacting the first substrate and the second substrate to the same polishing pad, wherein pressures applied to the first substrate and the second substrate are independently controllable; determining a difference between a first expected required polish time for the first substrate and a second expected required polish time for the second substrate using the first pre-polish thickness and the second pre-polish thickness; determining a duration of an initial period based on the difference between the first expected required polish time and the second expected required polish time; for the initial period at a beginning of a polishing operation, applying no pressure to whichever of the first substrate and the second substrate has a lesser expected required polish time while simultaneously applying pressure to whichever of the first substrate and the second substrate has a greater expected required polish time; and after the initial period, applying pressure to both the first substrate and the second substrate.