JPS6468474A - Formation of film - Google Patents

Abstract

PURPOSE:To form a W film while preventing the erosion by sublimation of Si by controlling the supply of the gas for forming the W film with time at the time of forming the W film by a CVD method using gaseous WF6 on an Si substrate having a patterned structure consisting of SiO2 and Si. CONSTITUTION:A semiconductor wafer 2 having the patterned structure composed of Si and SiO2 on the surface to be treated is installed in a vacuum chamber 1 and is heated by an IR lamp 7 via an installation base 3. A gaseous mixture composed of gaseous WF6 for film growth and carrier gas consisting of H2 and Ar is supplied to the chamber from gas introducing ports 10, 11. The first reduction of WF6 is executed by Si for pattern formation of the semiconductor wafer, by which reduced W 31 is formed on Si 30. After the W film 31 is formed thinly on the Si 30, the reduction of the WF6 is effected by the gaseous H2 in the gaseous mixture so that the subsequent growth of the W is contrived. The supply rate of the gaseous mixture in the final period of the reaction is decreased for the above-mentioned purpose to decrease the amt. of the Si to be used for reducing the WF6 as far as possible. After the W film is thinly formed on the Si, the WF6 is reduced by the H2 without consuming the Si and, therefore, the growth of the W on the Si is expedited by sharply increasing the supply of the gaseous mixture.