Process for passivating treatment of piping system for high- purity gas

摘要

A high-concentration ozone gas having a concentration of at least 50 VOL % of ozone in the ozone-oxygen system is acted within the temperature range of a normal temperature to 60° C. on an ultrapurity- gas piping system for use in a semiconductor manufacturing apparatus and the like or on a metal component part for use in an ultrahigh-vacuum apparatus to form a passivation film on the interior metal surface thereof.