Fluorine passivation of stainless steel

Abstract Fluorine passivation technology of metal surface for ULSI process equipments is investigated and the passivated film quality is evaluated. Well-polished and pretreated bare surfaces of stainless steel are passivated with oxygen-free high pure fluorine (O2 and HF less than 1 wppm) and a uniform and stable passivated surface is obtained by direct fluoridation and succeeding thermal modification (heat-treatment in nitrogen) (1) (2). It has been confirmed that the nonstoichiometric structure produced by the first step fluoridation is converted to the stoichiometric structure by the thermal modification. Passivation performance such as corrosion-free and outgas-free is achieved as a result of this thermal modification effect.