摘要 |
<p>MASKING PORTIONS OF A SUBSTRATE Certain mask materials, such as gold, are difficult to remove without damaging the underlying workpiece. This problem is solved in a process wherein, as a first step, a "parting" layer of a metal selected from the group consisting of nickel, aluminum, indium and tin is applied to the substrate to be masked. Over the parting layer is applied the masking layer. After processing,the parting layer is treated to detach it along with the mask from the substrate. For proton bombardment of a substrate which included gallium arsenide, the parting layer is preferably nickel, the mask is preferably gold, and the detaching agent includes hydrochloric acid.</p> |