Low-temperature in-situ dry cleaning process for semiconductor wafer

Abstract

A low-temperature (350.degree. C. to 750.degree. C.) in-situ dry cleaning process for removing native oxide (and other contaminants) from a semiconductor wafer surface, that can be used with either batch or single-wafer semiconductor device manufacturing reactors. A wafer is contacted with a dry cleaning mixture of digermane Ge.sub.2 H.sub.6 and hydrogen gas (51). The digermane-to-hydrogen flow ratio is small enough (usually between 1 ppm to 100 ppm) to ensure effective wafer surface cleaning without any germination deposition. Moreover, the dry cleaning mixture can include a halogen-containing gas (such as HCl or HBr) (52, 54) to enhance removal of metallic contaminants, and/or anhydrous HF gas (53, 54) to further enhance the native oxide removal process. The dry cleaning process can be further activated by introducing some or all of the hydrogen and/or an inert additive gas as a remote plasma. The digermane-based cleaning process of this invention can also be further activated by photo enhancement effects. This dry cleaning process is adaptable as a precleaning step for multiprocessing applications that, during transitions between process steps, reduce thermal cycling (FIGS. 3a-c) by reducing wafer temperature only to an idle temperature (350.degree. C.), and by reducing vacuum cycling via maintaining constant flow rates for carrier gases (FIG. 3a), thereby substantially reducing thermal stress and adsorption of residual impurities, while limiting dopant redistribution.

Dependencies are inferred from the claim text.