Effects of Mixing of Air with Etching Solution on Characteristics of Spray Etching

It is an old and a new problem to be solved to reduce the side etch as small as possible in the photo chemical machining. Several countermeasures for reducing the side etch, for example, increasing the adherence between a photoresist and a work material, increasing a spray pressure, selection and adjustment of a spray nozzle, increasing the concentration of an etching solution etc. have been trying in a long period. But there are hardly epochmaking countermeasures to reduce the side etch. While the powderless etching processes are useful for specified materials, it has not become a usual process for the common materials used generally in the photo chemical machining. In this research, a spray etching method in which a compressed air is mixed into the etching solution was tried and the effects of the mixing of air on the etching characteristics of the spray etching, especially, on the etch rate and the side etch were studied.