Aerodynamic aerosol chamber

Abstract

An aerosol cleaning apparatus and a method of treating a substrate within such an apparatus prevent contaminant recirculation by controlling the post-impingement exhaust flow through control of the aerodynamic behavior of the contaminant laden exhaust stream. By the present invention, the post-impingement exhaust flow is divided into two streams. A first stream is the main stream flowing initially over the contaminated side of the wafer and carrying most of the suspended contaminants into the exhaust. The second stream flows initially over the cleaned side of the wafer and eventually into the exhaust stream. A flow separator is provided for dividing the post-impingement aerosol spray into plural flow streams. Additionally, the aerosol chamber can advantageously include a shroud positioned within the aerosol chamber just to the side of the nozzle but further away from the exhaust than the nozzle for restricting flow from the second post-impingement stream around the nozzle and into the first post-impingement stream. In accordance with a preferred embodiment, the apparatus is designed for cleaning the surface of a semiconductor wafer by impinging the surface with a cryogenic aerosol spray.