JPS5557807A - Production of diffraction grating - Google Patents

Abstract

PURPOSE:To obtain the diffraction grating of superior performance by subsequently laminating a metal layer and photosensitive resin layer on the surface of inorganic material, forming a diffraction grating in the resin layer and etching the metal layer with said diffraction grating as a mask thence etching the inorganic material with the metal film as a mask. CONSTITUTION:For example, a glass substrate 10 is vacuum-evaporated thereon with a metal film 6 of Al or the like, on which is then coated and formed a photosensitive resin layer. A grating 15 is formed by radiating laser light followed by developing, thence with the grating 15 as a mask the metal film is ion-etched to form a metal grating 16. With the grating 16 as a mask, the substrate 1 is worked by reactive plasma etching to obtain a grating 17 thereon. The metal film 6 is removed to complete a glass diffraction grating 17. Since the metal film 6 reflects the laser 14, production of ghosts in the photosensitvie resin layer as with conventional methods wherein no metal film 6 is used is obviated and the patterns of the photosensitive resin will not collapse at the etching of the metal film. In addition, the good directivity of the reactive plasma etching enables the precision diffraction grating to be obtained.