A multi-step wafer-level run-to-run controller with sampled measurements for furnace deposition and CMP process flows: APC: Advanced process control

This paper describes a multi-step Run-to-Run controller design for a class of furnace deposition and CMP process flows. The wafer-to-wafer thickness variation introduced by the furnace deposition process has been compensated for by a wafer-level CMP controller. To avoid measuring all wafers in a lot and to reduce metrology cost, knowledge of upstream furnace process was employed and a piecewise linear function has been utilized to interpolate missing metrology data. Results are shown to illustrate the effectiveness of the described control method.