ETCHING METHOD AND MANUFACTURE OF SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To restrain dispersion of characteristics of a semiconductor device by removing an oxide layer by using a removal agent of an oxide layer after saturation of increase of thickness of an oxide layer in a surface of an etching member, by bringing oxidizer into contact with a surface of an etching member. SOLUTION: A resist 8 is formed on an active layer 3 excepting a region wherein a recess is to be formed. An 80Å-thick oxide layer 9 is formed in a surface of the active layer 3 which is an etching member by immersing it in hydrogen chloride water as an oxidizer of concentration of 20%, for example for about two minutes. Since enough oxidation of a surface of the active layer 3 is carried out by taking fully long oxidation time in this way, increase of film thickness of the oxide layer 9 is saturated and film thickness of the oxide layer 9 becomes uniform in an in-plane direction in parallel to a major plane of a semiconductor substrate 1. Then, the oxide layer 9 is removed by immersing the oxide layer 9 in tartraric acid solution of concentration of 50%. Accordingly, a recess part 6 of uniform depth of 80Åis formed.