Cantilever diffusion tube apparatus and method

Abstract

A cantilever diffusion tube apparatus includes a quartz cantilever tube having a support end clamped to a laterally movable carriage mechanism and an outer end portion containing a plurality of spaced semiconductor wafers. The cantilever tube is coaxially aligned with a diffusion tube of a diffusion furnace. The support end of the cantilever tube is sealed by a door plate through which a gas tube extends. The wafers are loaded into the cantilever tube through a window opening. The carriage then moves the cantilever tube and wafers therein into the diffusion tube. Reactant gases are caused to flow into the cantilever tube, between the heated wafers therein, and out of the cantilever tube. Then purging gas is caused to flow through the cantilever tube and wafers therein. Withdrawal of the cantilever tube from the diffusion tube is then performed as the purging gas flow continues, avoiding excessive thermal shock, premature exposure of wafers to ambient oxygen and exposure of the wafers to air containing defect-causing particles. The cantilever tube, when contaminated after a number of runs, is easily exchanged for a clean one, avoiding the need for frequent cleaning of the diffusion tube.

Dependencies are inferred from the claim text.