PURPOSE: To manufacture a semiconductor without using gold by a method wherein a resist is applied on a substrate, and after a resist pattern has been formed by vapor-depositing Sn and the like, Sn and the like is etched by performing an RIE (reactive ion etching), the lower layer resist is removed using the Sn and the like as a mask, and ions are implanted.

CONSTITUTION: An epitaxial layer 12 is formed on a semiconductive GaAs substrate 11, a resist 13 is applied on the substrate 11 in the prescribed thickness, and baked by applying heat. Then, an Sn layer 14 is formed by vapor- depositing Sn, a resist 15 is applied thereon, and a pattern developing operation is performed. Subsequently, Sn is etched by performing an RIE (reactive ion etching) using CCl2F2-containing gas. At this point, protons are projected under the prescribed condition using Sn as a mask, and when the resist is dissolved, the GaAs epitaxial layer can be separated. As a result, a mask can be formed easily, because the surface of the substrate becomes flat by resist coating even when the substrate 11 has a stepping.