摘要 |
PROBLEM TO BE SOLVED: To provide a wet etching device, wherein final point detection accuracy is improved without increasing the number of optical sensors. SOLUTION: Rays from a light source 18 is made to vibrate by a vibration mirror 22, and vibration rays from the vibration mirror 22 are turned on a substrate 11 by a turning mirror 23. Rays reflected by the turning mirror 23 is enlarged linearly on the substrate 11 by a capacitor lens 24. Since the detection area on the substrate 11 is enlarged, dependence of a pattern and dispersion of etching rate on in-plane irregularities of film quality and film thickness can be averaged, and final point detection accuracy can be improved.
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