しまパターン投影式自動焦点合わせ法(第1報) : 理論解析と実験的検証

概要

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The stripe pattern projection system is analyzed theoretically and experimentally in order to improve detection precision in automatic focusing which is included in the visual inspection equipments used for semiconductor. The design guide for the best system is also described. In the theoretical analysis, the mask defocus, the size of illumination source, the pupil diameter, the wafer defocus and the wavelength for illumination are considered. The contrast variations of projected patterns are calculated in case that the wafer is assumed to have a diffusing or mirror surface. In the experiment using wafers in production, the detected contrast exists between the ones calculated in the afore mentioned two surfaces. The theoretical values coincide with the experimental ones qualitatively. By this suitable design, it is possible to obtain 0.3 μm precision in automatic focusing.
公益社団法人精密工学会の論文
1990-07-05