Slotted cantilever diffusion tube system and method and apparatus for loading

An apparatus for carrying a plurality of spaced semiconductor wafers into and out of a furnace and also for holding said wafers during a wafer processing operation at elevated temperatures inside said furnace, said apparatus comprising in combination:

• (a) a tube for holding said wafers therein and having a wall and a first end and a second end;
• (b) cantilever supporting means attached to said first end of said tube for effectuating supporting of said tube in cantilever fashion during insertion and withdrawal of said tube into and out of said furnace;
• (c) an opening in said wall of said tube for effectuting loading of said wafers into said tube;
• (d) means for covering said opening while said wafers are in said tube;
• (e) means for effectuating flow of gas into and out of said tube, through said plurality of spaced wafers located inside said tube, and out of said tube while said tube is being moved in and out of said furnace and while said wafers are being held in said furnace;
• (f) wafer transfer means for effectuating transfer of said plurality of wafers into and out of said tube;
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• (g) soft landing means included in said cantilever supporting means for effectuating gently lowering said second end of said first tube onto a bottom inner surface of said furnace after insertion of said first tube into said furnace and before lowering said first end of said first tube onto said bottom inner surface of said furnace to avoid excessive stresses near said first end of said first tube.

A method for carring a plurality of spaced semiconductor wafers into and out of a furnace and also for holding said wafers during a wafer processing operation at elevated temperatures inside said furnace, said method comprising the steps of:

• (a) holding a rigid first tube in cantilever fashion at a first end thereof, said first tube having an open second end, a wall, and an elongated slot in a bottom portion of said wall, said elongated slot extending from said second end along said bottom portion of said wall to a portion of said first tube in which wafer boats are to be positioned;
• (b) placing a first wafer boat on a platform adjacent to said open second end of said first tube, said platform being sufficiently narrow to pass through said elongated slot without touching said first tube;
• (c) moving said platform and said first wafer boat therein so that said platform passes through said elongated slot without touching said first tube and said first wafer boat moves into said first tube thorugh said open end without touching said first tube;
• (d) lowering said platform through said elongated slot to clear said first tube and thereby set said first wafer boat on a bottom inner surface of said first tube so that the bottom surface of said first wafer boat sealabley covers a predetermined portion of said elongated slot;
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• (e) causing gas to flow into said first tube through said wafers and out of said first tube and concurrently moving said first tube with said first wafer boat therein into said furnace.

An apparatus for effectuating carrying of a plurality of spaced semiconductor wafers into and out of a furnace and also for holding said wafers during a wafer processing operation at elevated temperatures inside said furnace, said apparatus comprising in combination:

• (a) a first tube for holding said wafers therein, said first tube having a first end and an open second end, and a wall, said first tube having an elongated slot in a bottom portion of said wall, said elongated slot extending from said open second end along said bottom portion of said wall to a portion of said first tube in which wafer boats are to be positioned;
• (b) cantilever supporting means attached to said first end of said first tube for effectuating supporting of said first tube in cantilever fashion during insertion and withdrawal of said first tube into and out of said furnace;
• (c) removable first wafer boat means supporting at least some of said wafers, for supporting those wafers over said elongated slot when said first wafer boat means is positioned inside said first tube on the bottom inner surface thereof;
• (d) means for effectuating flow of gas into said first tube, through said plurality of spaced wafers inside said first tube, and out of said tube while said first tube is in said furnace and while said wafers are being held over said elongated slot;
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• (e) boat carrying means extendable through said elongated slot for lifting said first wafer boat means above the bottom inner surface of said first tube, laterally moving said first wafer boat along the interior of said first tube above said elongated slot without any portion of said first wafer boat, without any of said wafers, or any portion of said boat carrying means touching any portion of said first tube, to effectuate transferring said first wafer boat and wafers therein into and out of said first tube.