Method and apparatus for combining reactive gases while delaying reaction between same

Abstract

This invention is directed to a method and apparatus of delaying the reaction between a first reactive gas and a second reactive gas as the first reactive gas flows into the second reactive gas. The method comprises the steps of surrounding the first reactive gas with a non-reactive gas to form an insulated first reactive gas; and flowing the insulated first reactive gas into the second reactive gas. A sweep gas is used to impart momentum to the insulated first reactive gas. The apparatus comprises three coaxial tubular members which are used to introduce the first reaction gas, the non-reactive gas, and the sweep gas. The apparatus may be installed in a semiconductor device fabrication process either just upstream of the house exhaust line or upstream of an ODC or air pollution abatement device.

1 . A method of delaying the reaction between a first reactive gas and a second reactive gas as said first reactive gas flows into said second reactive gas, comprising: 
 surrounding said first reactive gas with a non-reactive gas to form an insulated first reactive gas; and    flowing said insulated first reactive gas into said second reactive gas.    
     
     
         2 . A method as set forth in claim I further comprising the step of sweeping the insulated first reactive gas with a sweep gas to provide it with increased momentum during the flowing step.  
     
     
         3 . The method of    claim 2    wherein prior to said surrounding and sweeping steps, the first reactive gas, the non-reactive gas, and the sweep gas flow through a set of three coaxial tubes; the first reactive gas flowing through the innermost tube, the sweep gas flowing through an annulus formed by the outermost tube and the intermediate tube, and the non-reactive gas flowing through an annulus formed by the intermediate tube and the innermost tube.  
     
     
         4 . The method of    claim 3    wherein the flow of said non-reactive gas through said annular space is laminar.  
     
     
         5 . The method of    claim 2    wherein said non-reactive gas comprises nitrogen or argon.  
     
     
         6 . The method of    claim 2    wherein said first reactive gas comprises one or more materials selected from the group consisting of BCl 3 , HBr, SiBr 4 , SiHBr 3 , BBr 3 , SiH 4 , tetra ethyl ortho silicate WF 6  and the like.  
     
     
         7 . The method of    claim 2    wherein said second reactive gas comprises water vapor, oxygen, or a mixture thereof.  
     
     
         8 . The method of    claim 2    wherein said sweep gas comprises nitrogen, air, or a mixture thereof.  
     
     
         9 . An apparatus for combining a first reactive gas with a second reactive gas and delaying reaction between reactive components in each of said gases, comprising: 
 first and second coaxial tubular members, the first tubular member being positioned within the second tubular member and forming an annular space therebetween;    means for flowing a first reactive gas through said first tubular member;    means for flowing a non-reactive gas through said annular space; and    a chamber through which a second reactive gas flows.    
     
     
         10 . An apparatus as set forth in    claim 9    further comprising: 
 a third coaxial tube member, the second tubular member being positioned within the third tubular member and forming an annulus therebetween; and  
 means for flowing a sweep gas through the annulus between the second and third tubular members to impart momentum.  
 
     
     
         11 . A semiconductor device fabrication process comprising a vacuum pump, a house exhaust line, and the apparatus of    claim 10   .  
     
     
         12 . A semiconductor device fabrication process as set forth in    claim 11    wherein the apparatus is installed just upstream of the house exhaust line.  
     
     
         13 . A semiconductor device fabrication process as set forth in    claim 11    further comprising an abatement device or other air pollution abatement device installed between the vacuum pump and the house exhaust line.  
     
     
         14 . A semiconductor device fabrication process as set forth in    claim 13    wherein the apparatus is installed upstream of the abatement device.  
     
     
         15 . A semiconductor device fabrication process as set forth in    claim 14    wherein the abatement device comprises a wet scrubber, a dry scrubber, or a thermal oxidation unit.