MANUFACTURE OF DIELECTRIC INSULATED AND ISOLATED SUBSTRATE

PURPOSE:To produce the titled dielectric insulated and islated substrate with island type single crystal regions subject to different depth and high precision by a method wherein the first etching mask film and the second etching mask film made of different material are laminated to be utilized as successive etching mask for etching operation. CONSTITUTION:The first etching mask film 11 is formed on a single crystal silicon substrate 1 to make openings. The second etching mask film 12 is formed by means of photoetching process so that the film 12 may be composed of a coated part to produce the second shallow etching surface with openings corresponding to the first film 11 and specified depth. Then the substrate 1 is etched to provide the openings with specified depth. Next the second film 12 is removed utilizing acid without doing damage to the first film 11. Then anisotropic etching process is repeated. Later after removing the first etching mask 11, a dielectric film 7 is formed to be coated with polycrystalline silicon 8 as a supporter. Thus island type single crystal regions with different depth may be produced by means of parallel grinding operation.