Etching

Abstract

Abstract PURPOSE:To avoid partial accelerated oxidation caused by light application at the time of anode oxidation and make the thickness of an N-type conductive layer uniform. CONSTITUTION:In an electrochemical etching method wherein a positive polarity DC voltage is applied to the N-type conductive layer of a silicon substrate 5 which is composed of the N-type conductive layer and a P-type conductive layer and the P-type conductive layer is removed by etching, etching is performed while an external light is shut off by a light shielding box 8. At that time, the N-type conductive layer side of the P-N junction silicon substrate 5 is connected to the anode side of a variable electric source 6 and the parts of the P-type conductive layer of the P-N junction silicon substrate 5 which are not etched are covered with a predetermined protective film 7. When a number of diaphragm patterns exist on the substrate 5 surface, the instants when anode oxidation reactions are started at the respective diaphragms are varied but, as the light shielding is provided, times required for forming oxide films are identical with each other. With this constitution, the thickness of the remaining N-type conductive layers can be made uniform.

Inventors

• 👤 Masaki Hirata
• 👤 平田　雅規

Bibliographic Details