Appeal No. 1997-4027
Application No. 08/300,111
from claim 1 in that claim 1 requires that the susceptor has an extension between the
support surface and the backside thereof to form a reactant gas barrier preventing
reaction gases from reaching the backside surface of said susceptor. (Brief, page 4,
second paragraph).
As stated above, in claim 1, the extension between the support surface and the
backside thereof refers to the portion of the susceptor not covered by the substrate that
extends outward toward the surrounding heat ring. Anderson discloses a pedestal (15)
which has a portion of the pedestal not covered by the substrate (16) that extends
outward toward the surrounding heat ring (36). (See Figure 3). Anderson discloses it is
important to control the distribution of gases across the wafer. Consequently,
Anderson discloses the vapor deposition chamber should have small spacing between
the gas inlet port and the nearest edge of the wafer as well as the exhaust port and the
nearest edge of the wafer. (Column 2, lines 1-10). Anderson also discloses it is
important to prevent reactant gases from flowing to the backside of the reaction
chamber. (Column 4, lines 5-9). To solve this problem, nitrogen or hydrogen gas is
added to the bottom of the reaction chamber to prevent the reactant gases from flowing
to the backside of the reaction chamber through the space between the pedestal and the
preheat ring. One of
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