JPS6453550A - Etching of metal thin-film substrate - Google Patents

Abstract

PURPOSE:To decide an end point of an etching operation accurately by a method wherein a metal thin-film substrate is irradiated with an infrared beam, a quantity of a transmitted beam at the metal thin-film substrate with reference to the irradiated beam is detected and the end point of the etching operation is decided by a change in the detected quantity of the transmitted beam. CONSTITUTION:An infrared light source 5 for irradiation use is arranged at the lower part and a fiber 4 for photodetection use is arranged at the upper part in such a way that a metal thin-film substrate 1 is sandwiched. In addition, the fiber 4 for photodetection use is connected to a detection unit which converts a photodetected transmitted beam into a voltage corresponding to a light quantity. An etching liquid is sprayed from a spray nozzle 3 onto the metal thin-film substrate 1 fixed to a spin fixture 2 while the spin fixture 2 is being turned; the metal thin-film substrate 1 is irradiated with an infrared beam from the infrared light source 5; an irradiated beam transmitting the metal thinfilm substrate 1 from the irradiated beam is photodetected by using the fiber 4 for photodetection use. The photodetected transmitted beam is detected after it has been converted into the voltage corresponding to the light quantity. When the voltage has been changed and has reached a definite value, this value is decided an as end point of an etching operation; a spraying operation of the etching liquid from the spray nozzle 3 is stopped.