The present invention is a method of forming micro through holes in printed wiring board substrate materials by means of chemical etching.In a typical printed wiring board substrate material consisting of a resinous dielectric base material, (which may or may not incorporate glass fibers), clad on both sides by a conductive layer, after the dielectric material in specific locations where through holes are to be formed is exposed by typical processes in which the conductor layer is selectively removed by etching, said exposed dielectric material is first softened, then removed by chemical etching involving several steps and procedures as well as a variety of chemical solutions, under vibratory agitation, forming through holes in said locations of 100 microns diameter or less.Employing the method of the present invention it is possible to determine the position, size and shape of the through hole required and also by means of plating to connect the conductive layers through the dielectric forming micro plated through holes in printed wiring boards.