Appeal No. 2002-0697
Application No. 09/625,857
To operate the S1 diffusion apparatus, a quartz boat 24
containing untreated wafers W is mounted on the lid body 26 and
the lid body is raised to lift the boat 24 and wafers W into the
process tube 21 and to close the bottom of the tube.
Subsequently,
[a]ir is evacuated from within the process tube 21
through the exhaust openings [25] and the process tube
21 is also heated to the prescribed temperature of
between 900° C. and 1200° C. by the heater 22.
Reaction gas is then introduced into the process tube
21 from the reaction gas introduction pipe 33. The
reaction gas is supplied to the semiconductor wafers W
. . . from the plurality of supply orifices 34 drilled
in the reaction gas introduction pipe 33. A gas such
as POCl3 or O2 is used as the reaction gas to diffuse
phosphorous into the semiconductor wafers W. The
apparatus is then evacuated through the exhaust
openings 25 by an exhaust apparatus, to exhaust both
excess reaction gas and also any reaction products.
At this point, a circulation gas such as N2 or Ar
is supplied from the circulation gas introduction
opening 42 to the circulation path 41 for circulation
gas provided in the lid body 26. The circulation gas
is heated to the vaporization temperature of the
reaction products, from 100° C. to 150° C., passes from
the circulation gas introduction opening 42, through
inner surface portion 41b of the circulation path 41
formed . . . along the gap 41a by the shaft 38
connected to the motor shaft, and is exhausted from the
circulation gas exhaust opening 43. Therefore, the
inner wall portion of the lid body 26 by the process
tube 21 is heated to between 100 C. and 200 C., to
ensure that reaction products do not adhere to the lid
body 26. Circulation gas that does not exhaust from
the circulation gas exhaust opening 43 passes through
the gap 44 . . . and is discharged from the exhaust
openings 25. The gap 44 is arranged so as to bend, so
that reaction components such as Cl2 and HCl that are
generated in the process tube 21 do not intrude toward
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Last modified: November 3, 2007