Abstract: A method for cleaning metallic impurities from a silicon surface of a semiconductor device is described. The first method includes, in sequence, the steps of:(a) exposing the silicon surface for a first time to a plasma afterglow anhydrous cleaning gas mixture containing nitric oxide and hydrogen chloride together with an inert carrier gas to remove metallic impurities, and then either;(b) exposing that surface for a second time to a plasma afterglow gas mixture of a fluorocarbon gas and hydrogen or carbon dioxide to remove the silicon oxynitrochloride film which is formed by step (a), leaving a fluorocarbon polymer film; and(c) exposing the surface for a third time to a plasma afterglow gas of oxygen to remove the fluorocarbon polymer film deposited in step (b); or(d) exposing that surface for a second time to a plasma afterglow gas mixture of inorganic fluorine compound gas, O.sub.2 and carrier gas to remove the silicon oxynitrochlorine film which is formed in step (a).

Abstract: A method for cleaning the surface of a silicon semiconductor device comprising the steps of:(a) exposing, for a first time, said device for a predetermined time period to an anhydrous cleaning gas mixture containing nitric oxide and hydrogen chloride together with an inert carrier gas; and(b) exposing, for a second time, said device for a predetermined second time period to a gaseous plasma formed of CF.sub.4, H.sub.2 and N.sub.2 at RF power.