Method of manufacturing micro-optic device

A method of manufacturing a micro-optic device including a mirror and a structure other than the mirror on a single crystal silicon substrate, comprising the steps of:

• providing an SOI substrate including a first and a second single crystal silicon layer and an intermediate insulating layer interposed between the single crystal silicon layers and forming a mask layer on the top surface of the first layer;
• patterning the mask layer by photolithography to form a mask having a pattern which defines a mirror forming surface which is perpendicular to a sheet surface of the substrate formed by the first single crystal layer and which is aligned with either (100) plane or (111) plane of the first single crystal layer, and sidewall surfaces which are perpendicular to the sheet surface of the substrate;
• removing portions of the first single crystal layer which are not covered by the mask by an anisotropic gas reactive dry etching until the intermediate insulating layer becomes exposed;
• smoothening the mirror forming surface and the sidewall surfaces exposed by the dry etching of the first single crystal layer which are aligned with either the (100) plane or the (111) plane by a wet etching which exhibits an anisotropy with respect to the silicon;
• and
• coating the smoothened mirror forming surface with a metal having a high reflectivity.