Apparatus and method for removing minute particles from a substrate.

摘要

Apparatus for removing small particles from a substrate comprises a source of fluid carbon dioxide, a first orifice (10) for expanding a portion of the fluid carbon dioxide and find droplets of liquid carbon dioxide, a coalescing chamber (14) for converting the first mixture into a second mixture containing gaseous carbon dioxide and larger liquid droplets of carbon dioxide, a second expansion orifice (16) for converting said second mixture into a third mixture containing solid particles of carbon dioxide and gaseous carbon dioxide, and a divergent channel 20 having an exit port arranged to direct mixture toward the substrate. In using the apparatus, a source of fluid carbon dioxide having an enthalpy below about 135 BTU per pound (based on an enthalpy of zero at 150 psia for a saturated liquid) is employed.