MICROCLUSTER-SURFACE INTERACTIONS - A NEW METHOD FOR SURFACE CLEANING

Surfaces contaminated by solid particulates and organic films can be c leaned by exposing substrates to a beam of energetic microclusters. Mi croclusters are defined here as multiply charged, initially liquid agg regates with prevalent radii in the range 0.01-0.5 mu m. An in-situ va cuum surface cleaning process is described using microcluster beams fo rmed by electrohydrodynamic emission from capillary emitters. Surface cleaning mechanisms are proposed including a model based on transferen ce of impulsive forces during collisions between microclusters and sol id particles. Microshocks induced in thin contaminant films impacted b y microclusters are also discussed. Implications of this novel technol ogy for cleaning semiconductor wafers is emphasized. (C) 1998 Elsevier Science B.V.