MASKING PORTIONS OF A SUBSTRATE

摘要

A removable mask (22) protects at least one portion of a substrate (10) during treatment such as irradiation thereof. To obtain mask (22), there is applied over said portion of substrate (10) a parting layer (44) of a metal selected from the group consisting of nickel, aluminum, indium and tin. Over the parting layer (44), there is applied the removable mask (22) of a material which is adherent and harmless to the parting layer (44) and is substantially impenetrable by the treatment. After irradiation, the parting layer (44) is treated with at least a detaching agent sufficiently to detach said parting layer (44) and the mask (22) from substrate (10). For proton bombardment of a substrate (10) which includes gallium arsenide, the parting layer (44) is preferably nickel, the mask is preferably gold and the detaching agent includes hydrochloric acid.