Abstract: A process is described for plating gold on metal surfaces electrically attached to a compound semiconductor. The procedure is particularly valuable where gold is to be in small holes or crevices in semiconductor structure since electroplating on the semiconductor surface is avoided. The process is useful for providing low inductance electrical connection to various parts of semiconductor devices such as to the source in gallium arsenide field-effect transistors.

Abstract: A mask structure is described which is extremely useful for use in various photoetching processes where etching rate depends on radiation intensity on the etched surface. Such processes are extremely useful for producing various geometrical patterns on surfaces. The mask is made up of alternate areas of opaque and transparent areas which when introduced into an optical imaging system ordinary aberrations produce a pattern on the surface to be etched with the desired continuous spatial variation of radiation intensity. A particular advantage of the mask structure is that it can easily be made using an Electron Beam Exposure System. The mask is particularly useful for electrochemical photoetching processes carried out on compound semiconductors. The mask structure is usefully used to photoetch integral lenses on light emitting diodes. This photoetching process produces a variety of lens structures on LED devices with great accuracy.

Abstract: A spray plating method is shown wherein a multiplicity of spray nozzles mounted on a feed pipe direct a high velocity spray at an article to be plated. The spray is deflected onto portions of the article by metal deflectors located near the article. The deflectors serve as the anode of the plating process. This results in a high current density and a high plating rate. The method is advantageously used for hard plating gold onto connector pins or other articles on a continuous strip-plating line. In another application, metal may be selectively removed from an article. Different portions of an article may have different amounts of metal deposited or removed.