Method capable of forming a fine pattern without crystal defects

Abstract

In a method of processing a compound semiconductor wafer to deposit or form a specific layer on a wafer surface, to partially remove the specific layer to partially expose the wafer surface, and to etch a partially exposed area of the wafer, etching is performed by irradiating an electron beam and a specific gas which may be, for example, chlorine gas, bromine gas, iodine, or their compounds. Portions subjected to irradiation of both the electron beam and the specific gas are etched from the wafer. The specific layer is deposited or formed in the form of an oxide layer on the wafer surface by spraying an oxygen gas onto the wafer surface with light irradiated on the wafer surface. Such an oxide layer may be either an adsorbed molecular layer of the oxygen gas or a chemically reacted layer which results from reaction of the oxygen gas with the wafer by the help of irradiation of the light. Alternatively, the specific layer may be either a sulphide layer or a nitride layer. The specific layer and the wafer may be removed and etched by the use of different gases which may be a hydrogen gas and a chlorine gas, respectively. In addition, the above-mentioned processing may be carried out without exposure of the wafer to air by the use of an apparatus which comprises a plurality of rooms or chambers airtightly coupled to one another.