Ex Parte Hwang et al

Board of Patent Appeals and Interferences

Aug 16, 2003

09354459 (B.P.A.I. Aug. 16, 2003)

The opinion in support of the decision being entered today was not written
for publication and is not binding precedent of the Board.
Paper No. 20
UNITED STATES PATENT AND TRADEMARK OFFICE
____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________
Ex parte MING JANG HWANG, KEIZO HOSODA,
SHINTARO AOYAMA, TADASHI TERASAKI and TSUYOSHI TAMARU
____________
Appeal No. 2002-1178
Application No. 09/354,459
____________
ON BRIEF
____________
Before HAIRSTON, GROSS, and BARRY, Administrative Patent Judges.
HAIRSTON, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal of claims 1 through 4, 6 through 8 and 21 through 28.
The disclosed invention relates to a method of reducing by-product deposition inside a wafer
processing chamber by introducing a heated gas into the chamber concurrently with the introduction
of reactant gases into the chamber to maintain the inner wall of the chamber at a temperature
sufficiently high to maintain a reaction product formed by the reactant gases in a gaseous phase of
the sublimation curve for the reaction product when contacting the inner wall.
Appeal No. 2002-1178
Application No. 09/354,459
1 A copy of the translation of this reference is attached.
2
Claim 1 is the only independent claim on appeal, and it reads as follows:
1. A method of reducing by-product deposition inside wafer processing equipment,
comprising:
providing a chamber having a peripheral inner wall;
placing a semiconductor wafer within the chamber;
providing a plurality of reactant gases;
introducing said plurality of reactant gases into the chamber and reacting the gases to form a
reaction product having a solid and a gaseous phase, said solid phase being present at known
pressure/ temperature levels in relation to a known sublimation curve for said reaction product;
providing a heated gas; and
introducing said heated gas into the chamber concurrently with said step of introducing a
plurality of reactant gases into the chamber to maintain the peripheral inner wall at a temperature
sufficiently high to maintain said reaction product in the gaseous phase of said sublimation curve
when contacting the peripheral inner wall.
The references relied on by the examiner are:
Mikoshiba et al. (Mikoshiba) 4,989,541 Feb. 5, 1991
Ohashi et al. (Ohashi) 6,059,885 May 9, 2000
(filed Dec. 16, 1997)
Nozaki et al. (Nozaki) 61-1178241 June 5, 1986
(Japanese Patent Application)
Pierson, “Handbook of Chemical Vapor Deposition (CVD),” Noyes Publications (1992), pages 222
through 226.
Appeal No. 2002-1178
Application No. 09/354,459
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Claims 4 and 24 stand rejected under the second paragraph of 35 U.S.C. § 112 as indefinite
because hydrogen chloride is claimed as a reactant gas that is introduced into the chamber as
opposed to a by-product gas produced from the reaction of the reactant gases.
Claims 1 through 3, 6 through 8, 21 through 23 and 25 through 28 stand rejected under 35
U.S.C. § 103(a) as being unpatentable over Mikoshiba in view of Nozaki.
Claims 1 through 3, 6 through 8, 21 through 23 and 25 through 28 stand rejected under 35
U.S.C. § 103(a) as being unpatentable over Ohashi in view of Nozaki.
Claims 4 and 24 stand rejected under 35 U.S.C. § 103(a) as being unpatentable over
Mikoshiba in view of Nozaki, appellants’ admitted prior art and Pierson, or Ohashi in view of
Nozaki, appellants’ admitted prior art and Pierson.
Reference is made to the second supplemental brief and reply brief (paper numbers 15 and
17) and the answer (paper number 16) for the respective positions of the appellants and the
examiner.
OPINION
We have carefully considered the entire record before us, and we will sustain the
indefiniteness rejection of claims 4 and 24, and reverse the obviousness rejections of claims 1
through 4, 6 through 8 and 21 through 28.
Turning first as we must to the indefiniteness rejection, appellants argue (reply brief, pages 2
and 3) that:
Appeal No. 2002-1178
Application No. 09/354,459
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The fact that hydrogen chloride is stated to be reacted with ammonia (page 2, lines
10 and 11) indicates that reactant gases introduced into the chamber can include
these gases. Furthermore, some of the class of possible reactant gases is clearly set
forth in the paragraph bridging pages 7 and 8 of the specification as reactant gases 22
and these gases specifically include ammonia and hydrogen chloride among other
gases.
Appellants’ arguments to the contrary notwithstanding, the examiner correctly concludes
(answer, page 6) that:
. . . HCl is not one of the plurality of reactant gases introduced into the reaction
chamber, as presently claimed, but is instead a by-product of the reaction of the
reactant gases fed into the chamber -- specifically of ammonia and chlorine-
containing reactants. One of ordinary skill knows from Applicant’s [sic,
Applicants’] specification that HCl is not introduced to the reaction chamber but is,
instead, formed within the chamber as a by-product, itself, that goes on to react
with more ammonia to produce the undesired-but-unavoidable ammonium chloride .
. . .
Inasmuch as hydrogen chloride is not introduced into the chamber as a reactant gas, claims 4
and 24 are rendered indefinite by the claim limitation that hydrogen chloride is one of the plurality
of reactant gases introduced into the chamber. As a result thereof, the indefiniteness rejection of
claims 4 and 24 is sustained.
In claim 1 on appeal, the heated gas introduced into the chamber maintains the peripheral
inner wall of the chamber at a temperature sufficiently high to maintain the reaction product in the
gaseous phase of its sublimation curve when contacting the peripheral inner wall. In Mikoshiba, the
control gas 8 from nozzle 6 functions to keep the material gas flow from ever touching the
peripheral inner wall of the chamber 1 (Figure 1A; column 2, lines 19 through 23, 40 and 41;
column 4, lines 10 through 14; column 5, lines 1 through 3 and 21 through 26). By relying on the
Appeal No. 2002-1178
Application No. 09/354,459
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heated gas teachings of Nozaki, the examiner tacitly admits (answer, pages 8 and 9) that the control
gas 8 in Mikoshiba is not a heated gas. Although Nozaki introduces a heated carrier gas into the
chamber 7 via supply port 23, Nozaki, like Mikoshiba, uses the heated gas to prevent the reaction
gas from coming into contact with the side walls of the chamber (translation, page 5). Even if the
reactant gases in Mikoshiba and Nozaki are maintained on the gaseous sides of their respective
sublimation curves, as argued by the examiner (answer, pages 9 and 10), neither Mikoshiba nor
Nozaki teaches or would have suggested to the skilled artisan maintaining “said reaction product in
the gaseous phase of said sublimation curve when contacting the peripheral inner wall.” Thus, the
obviousness rejection of claims 1 through 3, 6 through 8, 21 through 23 and 25 through 28 is
reversed.
In the alternative rejection of claims 1 through 3, 6 through 8, 21 through 23 and 25 through
28, Ohashi, like Mikoshiba and Nozaki, does not want the reactant gas to contact the inner wall of
the chamber (column 12, lines 65 through 67; column 15, lines 35 through 38). The examiner
acknowledges (answer, page 12) that Ohashi does not disclose the claimed heated gas. Thus, the
obviousness rejection of claims 1 through 3, 6 through 8, 21 through 23 and 25 through 28 is
reversed because the reactant gases in the references do not contact the “peripheral inner wall” of
either chamber.
The obviousness rejections of claims 4 and 24 are reversed because neither the admitted
prior art nor the teachings of Pierson cure the noted shortcomings in the teachings of Mikoshiba,
Nozaki and Ohashi.
Appeal No. 2002-1178
Application No. 09/354,459
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DECISION
The decision of the examiner rejecting claims 4 and 24 under the second paragraph of 35
U.S.C. § 112 is affirmed, and the decision of the examiner rejecting claims 1 through 4, 6 through 8
and 21 through 28 under 35 U.S.C. § 103(a) is reversed. Accordingly, the decision of the examiner
is affirmed-in-part.
No time period for taking any subsequent action in connection with this appeal may be
extended under 37 CFR § 1.136(a).
AFFIRMED-IN-PART
KENNETH W. HAIRSTON )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
ANITA PELLMAN GROSS ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
)
LANCE LEONARD BARRY )
Administrative Patent Judge )
KWH/lp
Appeal No. 2002-1178
Application No. 09/354,459
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