二焦点レンズを用いたシリコンウェーハの厚み測定

概要

論文の詳細を見る
The realization of on-machine measurement, in accuracy of under 0.1 μm, of the Total Thickness Variation (TTV) of large-diameter silicon wafers after grinding on a vacuum chuck is strongly required. In this paper, a thickness measuring method by using a double focus lens and the infrared ray that can transmit through the silicon wafer was proposed for high-precision in-site measurement of the TTV, without being affected by the flatness and structure of the vacuum chuck surface. In this method the focusing position was relatively moved from a rear surface of the wafer to a front surface by the objective lens, and the thickness was calculated from this moving distance. Refractive index of wafer became necessary in calculation so that the value was identified by using a double focus lens. The usage of a double focus lens enabled shortening of moving distance which resulted in short measuring time and high measuring accuracy.
社団法人日本機械学会の論文
2001-06-25