Semiconductor device having a silicon oxide film containing fluorine

Abstract

The semiconductor device has a multilayer structure wherein a substantially pure silicon dioxide film containing substantially no fluorine atom and a silicon dioxide film containing fluorine atoms are sequentially laminated on a substrate. Etching rate of a silicon dioxide film depends on a fluorine concentration in the film, so that a suitable etch selectivity of the silicon dioxide film containing fluorine atoms from the substantially pure silicon dioxide film can be obtained to form an oxide trench used for a trench interconnection and a via-hole used for a via-plug. The oxide film containing fluorine atoms has as good a quality as the silicon dioxide film not containing impurities has, thereby obtaining a superior characteristic of the semiconductor device. Addition of fluorine atoms reduces a specific permittivity to thereby obtain a higher speed.