| 摘要 |
PROBLEM TO BE SOLVED: To suppress the dispersion of film thickness in a WF face and between WF by making a process tube for vertical furnace into the duplex structure of an outer tube and an inner tube, and installing holes on the upper part and the sides of the inner tube so that process gas in the process tube uniformly spreads to the whole inner tube. SOLUTION: A process tube 4 formed of quartz and SiC is stored in a vertical furnace 3, and the duplex structure of an outer tube 4A to which gas is introduced and an inner tube 4B where gas is reacted and exhausted is obtained. Process gas is introduced between the outer tube 4A and the inner tube 4B, which are uniformly heated by a heater 2, from a gas introduction tube 5 formed in the process tube 4 and the gas is uniformly heated. Holes 4C are installed in the whole inner tube 4B, heated gas is introduced into the inner tube 4B from the holes 4C, and it is uniformly spread to whole wf8 held by a board 7 in the inner tube 4B. Then, process gas is exhausted from an exhaust tube 6 installed below the inner tube 4B.
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