METHOD OF MANUFACTURING SILICON MEMBRANE WITH ADJUSTED RESIDUAL STRESS

摘要

PROBLEM TO BE SOLVED: To obtain a designed residual stress accurately by producing a lightly doped stress free silicon membrane and then doping the membrane with impurities at an appropriate dose. SOLUTION: A ring pattern of film for blocking implantation of boron is formed on a silicon substrate 1. Boron is then implanted onto the substrate 1 to form a layer 2 heavily doped with boron and free from potential mismatch surrounded by the substrate 1 on which the ring pattern of film for blocking implantation of boron is formed. Subsequently, a local region of the substrate 1 is etched from the lower surface to form a membrane composed of a boron doped layer. According to the method, a membrane having accurate value of residual stress required for a very precise micromachine can be produced and the stress distribution is regulated to a desired value in the planar direction and thickness direction.