| 摘要 |
PURPOSE:To enable to detect an endpoint without fail by a method wherein the amount of fluctuations per prescribed time of the level of an electric signal is calculated, said amount of fluctuations is discriminated with the passage of time, and a judgement wherein the layer thickness has become zero is given when the fact that the above is in the first condition is detected in prescribed number of times. CONSTITUTION:A developing solution 52 is filled up in a developing vessel 51, and the lower layer 60 having the surface layer (the photoresist layer whereon a pattern is exposed) to be developed is fixed. A sideviewing lens barrel 20 is fixed in such a manner that the incident light sent from a prism 42 will be intersecting at right angle with the surface of the surface layer 61 using a fittings 36. The incident light coming from the prism 42 is reflected to the surface of the surface layer 61 and on the surface of the lower layer 60, and the intensity of the entire reflected light is changed. This reflected light reaches the tip of an optical fiber code 10, and it is conducted to an O/E converter 3 through the intermediary of an optical fiber code 12. The O/E converter 3 converts the incident optical signal, i.e., the change in intensity of the reflected light, into an analog electric signal using the photoelectric conversion element such as a photodiode and the like. Said analog electric signal is converted into a digital electric signal by an A/D converter 4, and it is inputted to a central processing unit (CPU)1. |
