| 摘要 |
PURPOSE:To apply wiring to a step difference part having favorable reproducibility without damaging a ground semiconductor layer by a method wherein an insulating film having openings for contact is formed on a substrate having step differences, a plating layer is formed using a metal thin film exposed in a wirng pattern type according to a resist as a cathode, and the metal thin film is etched using the plated layer thereof as a mask. CONSTITUTION:An emitter contact layer and an emitter layer 5 are formed in stripe mesa types by etching on a substrate 1. Then a base layer 4 is formed in a stripe mesa type by etching, moreover collector layer 3 is formed in a nesa type by etching, and a collector contact layer 2 is formed in a stripe mesa type by etching finally. Then AuGe electrodes 7 are formed on the collector and emitter layers, an AuZn electrode 8 is formed on the base layer, an SiO2 film 9 is deposited by the CVD method on the whole surface, openings are formed by etching the electrode parts, and a Ti film 10 and an Au film 11 are laminated in order on the whole surface of the wafer. A wiring pattern is formed out of a photo resist, gold plating 12 is performed using the Ti film 10, the Au film 11 as a cathode, and after the photo resist is removed, the Au film 11, the Ti film 10 are etched respectively according to ion etching using the wiring formed according to gold plating 12 as a mask.
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