Etching

Abstract

Abstract PURPOSE:To conduct patterning having an anisotropic etching shape by doping, with an impurity, only the surface layer section of a layer to be etched, performing patterning by means of charged particles and etching by optical pumping, diffusing the impurity in the surface layer section into the layer to be etched and activating the impurity. CONSTITUTION:A thin oxide film 2 is formed onto an Si substrate 1, and a polysilicon layer 3 is shaped onto the whole surface. Phosphorus ions are implanted by controlling the energy of ion implantation, phosphorus ions are doped to the surface layer section 3a of the polysilicon layer 3, the concentration of phosphorus only in the surface layer section 3a is increased. Photo-resist layers 4 are formed onto a required pattern, and unnecessary sections in the polysilicon layer 3 are etched up to immediately before the oxide film 2 as a foundation is exposed through an etching method employing plasma. The layers 3 and 4 are patterned to specified shapes through optical pumping etching by irradiating the polysilicon layer 3 with ultraviolet rays in a chlorine atmosphere. The photo-resist layers 4 are removed, and phosphorus is diffused to other sections through heat treatment, and activated, thus forming anisotropic etching shape without damage.

Inventors

• 👤 Keiji Shinohara

Bibliographic Details