Accuracy Estimation of Shape Measurement of Thin-Large Panel with Three-Point-Support Inverting Method

Abstract

This paper describes the error analysis and the repeatability of the shape measurement of thin-large panel by the three-point-support inverting method. In this measuring method, the stable measurement can be carried out because the measured object is supported horizontally by three points. Moreover, the true shape of the measured object can be obtained by cancelling the effects of gravity. However, accurate measurement of the shape of thin-large panel is difficult because there are many error factors originated from both the measuring system and measured object. It was found that the combined standard uncertainty due to the errors caused by the measuring system was 0.408µm and the motion accuracy of the measuring system was the dominant factor. Repeatability of the warp measurement was 0.254µm. Effects of the vibrations of the measuring system and the silicon wafer and the distortion of the silicon wafer due to the friction between the wafer and supports on the repeatability were equivalent. The influence of the data sampling interval was not insignificant when the warp was large.