| 摘要 |
PURPOSE:To enable a film thickness to be measured in an etching liquid and to obtain a high-reliable film thickness, by a method wherein a silicon wafer is irradiated with glow to detect light in which a transmitting light is separated into a wavelength region of 0.8-1.2mum. CONSTITUTION:An etching liquid 2 is leaked into a quartz etching vessel 1, a silicon wafer 3 is held, and a light irradiating portion 4 and a detection portion 8 are located at the outside. Glow forms a parallel light 6 by means of a convex lens 5 and an iris diaphragm 6, light transmitting the wafer 3 is separated into a wavelength region of 0.8-1.2mum, which reduces light absorption of the etching liquid and is suited to measurement of a film thickness, through a filter 7, and an electric output corresponding to intensity of a wavelength is detected by a detecting portion 8. This enables a film thickness to be measured in the etching liquid, and permits obtaining of a high-precise film thickness by causing the wafer to stop being etched when it is etched to a given film thickness. |
