JPS5630739A - Formation of polycrystalline silicon wiring layer - Google Patents

Abstract

PURPOSE:To enable multilayer wiring by a method wherein a polycrystalline Si at the unrequired portion of the wiring is oxidized, and make it an insulator to form an even wiring. CONSTITUTION:The polycrystalline Si 2 is vapor phased grown on an insulator 1 and a mask 3 is formed for an ion injection. As or other is injected after the polycrystalline Si 2 is etching eliminated as much as the expanded thickness by the oxidizing. When the mask 3 is eliminated and oxidized at a low temperature, a diffusion to the lateral direction is prevented and the oxidizing is accelerated by the As injection, the SiO2 film 4 is formed in thick at the injected part and in thin at the noninjected part, and the polycrystalline Si 2 is remained at the noninjected part. Since As is segregated and accumulated at the bottom of the SiO2 film, the density of As becomes thin at a side of the SiO2 film, the pattern conversion difference of the SiO2 film 4 becomes as much as the standard deviation of the projected range of As, the concave and the convex on the surface becomes also extremly even. By the injection of As or other to the remained polycrystalline Si 2 and the adding of a heat processing, a conductive layer 5 is obtained. According to this constitution, the fine wiring layer having a rectangular cross can be obtained in a high precision and the disconnection can be prevented and the high integration can be realized in the multilayer wiring.