Simultaneous Measurement of Warp and Thickness of Silicon Wafer Using Three-Point-Support Inverting Method

This paper proposes a method to measure thickness and warp of silicon wafer simultaneously. Warp was measured using the three-point-support inverting method. Then, thickness was obtained from the measured shapes of both top and back surfaces and the wafer deflection due to gravity which was calculated by numerical analysis. Since the calculated wafer deflection is affected by the thickness distribution, the self-consistent solution of the thickness was obtained by iteration. As a result, the error of the thickness measurement was ±0.72μm, indicating that the warp and thickness of the silicon wafer can be measured simultaneously.