ウエハ上微粒子およびウエハ内結晶空洞(COP)からの散乱光の理論的解析

概要

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In this study, the optical technology to detect small particles adhering to a wafer and crystal originated particles (COPs) existing in the wafer, whose diameters are approximately 0.1μm, is theoretically developed. The technology to separate COPs from detected particles is also developed. The intensity distribution of light scattered by particles and COPs is calculated using the Maxwell equation under the assumption that they are illuminated by laser light. The finite difference-time domain (FD-TD) method is used to solve the Maxwell equation. The following results were obtained by these calculations. Both particles and COPs are detected when an Ar-ion laser (λ= 488nm) with P-polarization is illuminated perpendicularly downward onto the wafer. and the obliquely scattered light is detected. Only particles are detected when a YAG Iaser (λ=532nm) with S-polarization is illuminated obliquely and the light scattered perpendicularly upward is detected. On the basis of the abovementioned results. it is theoretically verified that both particles and COPs Larger than 0.1μm in diameter are detected and recognized independently.
公益社団法人精密工学会の論文
2000-07-05