US 2002/0053191 A1 · Method for removing condensable aluminum chloride vapor from aluminum etch effluent

Abstract

A method and apparatus for trapping AlCl3 from an aluminum etch effluent includes a housing containing disposable trapping medium with a first trapping stage and a second trapping media positioned radially outward and axially downward, respectively, from the strap inlet at respective distances to take advantage of differences in heat exchange efficiencies between the trapping media and solid AlCl3 build-up on the trapping media and of resulting changes in partial vapor pressure of AlCl3 adjacent condensation surfaces as solid AlCl3 build-up occurs to initially induce condensation and build-up near the inlet, but then preferentially flow vapor to more distant trapping media as build-up occurs before the build-up clogs the inlet. The first stage trapping media has less surface density than the second stage trapping media, so that the first stage trapping media collect more than half, preferably 90-95% of the AlCl3 vapor with the media at ambient temperature, and so that the second stage trapping media remove the remaining AlCl3 vapor with the media at ambient temperature.

Claims39

Dependent claims

A method of trapping condensable AlCl3 from a gas flow effluent from an aluminum etch reaction chamber comprising a mixture comprising AlCl3 and Cl2, comprising:

directing the gas flow at a volume flow rate, a mass flow rate, and a temperature into a first stage of a trap chamber that comprises first trapping media with sufficient microsurface areas and of sufficient surface density for the volume flow rate, mass flow rate, and temperature of the gas flow to cause sufficient physical collisions of the AlCl3 with the microsurface areas when temperature of the first trapping media is ambient, to cool and condense more than half of the AlCl3 in the gas flow on the first trapping media;
directing the gas flow with the Cl2 and any remaining AlCl3 that was not condensed on the first trapping media into a second stage of the trap chamber that comprises second trapping media with a microsurface density that is greater than the microsurface density of the first trapping media and that has sufficient microsurface areas for the volume flow rate, mass flow rate, and temperature of the gas flow, to cause sufficient physical collisions of the AlCl3 in the gas flow, when temperature of the second trapping media is ambient, to cool and condense the remaining 5-10% of the AlCl3 in the gas flow on the second trapping media, leaving the gas flow after the second stage substantially free of AlCl3.

Dependencies are inferred from the claim text.

Method for removing condensable aluminum chloride vapor from aluminum etch effluent

Life of this patent

Method for removing condensable aluminum chloride vapor from aluminum etch effluent

Life of this patent

Abstract

Claims39