US Patent 7134946 Apparatus to treat and inspect a substrate

An apparatus for treating a substrate with a cryogenic impingement fluid includes a protective enclosure defining an internal cavity, a cryogenic fluid applicator positioned within the internal cavity and a snow generation system connected to the cryogenic fluid applicator. The snow generation system includes a condensing subsystem and a diluent or propellant gas subsystem. Each subsystem is connectable to a common gas source. The condensing subsystem includes a condenser for condensing liquid carbon dioxide into solid carbon dioxide particles, or dry ice snow. The condenser includes at least two segments of differing diameter connected to one another. Liquid carbon dioxide is introduced into the smaller diameter first segment and upon entering the larger diameter second segment, solidifies into dry ice particles. The dry ice particles, along with diluent or propellant gas produced from the diluent subsystem, are delivered to the cryogenic fluid applicator via a coaxial delivery tube.