Ex parte Moslehi

Board of Patent Appeals and Interferences

Jan 28, 2000

08847319 (B.P.A.I. Jan. 28, 2000)

Application for patent filed April 23, 1997. According1
to the appellant, this application is a continuation of
Application No. 08/332,528, filed October 31, 1994, now
abandoned.
1
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today
(1) was not written for publication in a law journal and
(2) is not binding precedent of the Board.
Paper No. 38
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte MEHRDAD M. MOSLEHI
_____________
Appeal No. 1999-1666
Application 08/847,3191
______________
ON BRIEF
_______________
Before HAIRSTON, FLEMING and GROSS, Administrative Patent
Judges.
HAIRSTON, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal under 35 U.S.C. § 134 from
Appeal No. 1999-1666
Application No. 08/847,319
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the examiner’s final rejection of claims 4, 47-52, and 54
which represent all of the claims remaining in the
application.
Appeal No. 1999-1666
Application No. 08/847,319
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Appellant’s After Final Amendment (Paper No. 28) to claim
4 was entered by the examiner (Paper No. 30).
The invention pertains to the fabrication of
microelectronics devices and integrated circuits. More
specifically, the invention relates to a method of directly
doping a semiconductor wafer by exposing a surface of the
wafer to a non-ionized process medium in order to directly
dope at least a portion of the surface of the wafer. The non-
ionized process medium comprises a dopant gas having an
organic compound of a dopant species. The organic compound in
the dopant gas is a material selected from the group
consisting of (CH ) B, (C H ) B, (OCH ) B, (CH S) BCH ,3 3 2 5 3 3 3 3 2 3
(CH ) BN(CH ) (CH ) BOCH and CH SB(CH ) . The process includes3 2 3 2, 3 2 3 3 3 2
the step of heating the wafer, thermally activating the dopant
species and causing solid state diffusion of the dopant
species into the semiconductor wafer surface. At least
portions of the semiconductor wafer surface are doped with p-
type doping, where the dopant species is boron.
Claim 4 is illustrative of the claimed invention, and
reads as follows:
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4. A direct doping method for semiconductor wafers,
comprising the steps of:
providing a semiconductor wafer having a surface;
exposing said surface of said wafer to a non-ionized
process medium in order to directly dope at least a portion of
said surface of said wafer, wherein said process medium
comprises a dopant gas, and wherein said dopant gas comprises
an organic compound of a dopant species; and
heating said wafer, thermally activating said dopant
species and causing solid state diffusion of said dopant
species into said semiconductor wafer surface, wherein said
doping is performed without the presence of plasma, wherein
said organic compound is a material selected from the group
consisting of (CH ) B, (C H ) B, (OCH ) B, (CH S) BCH ,3 3 2 5 3 3 3 3 2 3
(CH ) BN(CH ) , (CH ) BOCH , and CH SB(CH ) in order to dope at3 2 3 2 3 2 3 3 3 2
least portions of said surface of said semiconductor wafer
with p type doping, wherein said dopant species is boron,
wherein said semiconductor wafer is heated to a temperature in
the range of 650 C and 1150 C. o o
The prior art relied upon by the examiner as evidence of
obviousness are:
Melas et al. 4,734,514 Mar. 29, 1988
(Melas)
Bohling et al. 4,904,616 Feb. 27, 1990
(Bohling)
Kiyota et al. 5,387,545 Feb. 7, 1995
(Kiyota) (filed Dec. 12,
1991) Zhang et al. 5,424,244 Jun.
13, 1995
(Zhang) (filed Nov. 4,
1992)
The appealed claims stand rejected under 35 U.S.C. § 103
as follows:
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a) Claims 4, 47, 48, 50-52 and 54 stand rejected under
35 U.S.C. § 103(a) as being unpatentable over Kiyota in view
of Melas.
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b) Claim 49 stands rejected under 35 U.S.C. § 103(a) as
being unpatentable over Kiyota in view of Melas, Bohling and
Zhang.
Rather than reiterate the examiner’s full statement of
the above-noted rejections and the conflicting viewpoints
advanced by the examiner and appellant regarding those
rejections, we make reference to the examiner’s answer (Paper
No. 34) for the examiner’s reasoning in support of the
rejections, and appellant’s brief and reply brief (Paper No.
33 and Paper
No. 35, respectively) for appellant’s arguments thereagainst.
On page 4 of the brief, appellant indicated that claims
4, 47, 48, 50-52 and 54 stand or fall together and that claim
49 stands or falls alone. In keeping with appellant’s
groupings, we hereby select claims 4 and 49 from the separate
rejections for review, and we shall decide the appeal as to
the respective grounds of rejection on the basis of these
selected claims;
37 CFR § 1.192 (c)(7).
OPINION
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Application No. 08/847,319
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In reaching our decision in this appeal, we have given
careful consideration to appellant’s specification and claims,
to the applied prior art references, and to the respective
positions articulated by appellant and the examiner. As a
consequence of our review, we have made the determinations
which follow.
We will not sustain the examiner’s rejection of claims 4,
47, 48, 50-52 and 54 under 35 U.S.C. § 103(a). Likewise, it
follows that we also will not sustain the examiner’s rejection
of claim 49 under 35 U.S.C. § 103(a).
We first consider the rejection of claims 4, 47, 48,
50-52 and 54 under 35 U.S.C. § 103(a). The examiner (Answer,
page 4) basically relies on Kiyota for teaching all of the
features of independent claim 4 except for the use of an
organic compound of a dopant species. The examiner points to
Melas for its teaching of using an organic compound of a
dopant species for doping a semiconductor wafer. From there,
the examiner reasons that it would have been obvious to one of
ordinary skill in the art at the time the invention was made
to use a dopant species as taught by Melas in Kiyota’s direct
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doping process because the dopant species are conventional
dopant sources during gas phase doping.
The appellant responds to the rejection of page 6 of the
brief by indicating that the examiner’s proposed combination
of teachings is improper. In support thereof, the appellant
notes that Melas teaches a chemical vapor deposition method
which is not a direct doping method as required by the claims.
The examiner did not present any specific arguments addressing
the above-noted argument by the appellant. The appellant
followed-up with a reply brief reiterating the objection to
the examiner’s combination of prior art teachings.
Based on the record before us, we are in general
agreement with the appellant that the collective evidence
relied upon and the level of skill in the particular art would
not have suggested to one of ordinary skill in the art the
obviousness of the invention as set forth in claims 4, 47, 48,
50-52 and 54. Although Melas (col. 1, lines 14-25) does teach
doping a semiconductor wafer and the use of an organic
compound of a dopant species containing (CH ) B and (C H ) B,3 3 2 5 3
Melas teaches in column 6, lines 1-5 that these materials are
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used in a metal organic chemical vapor deposition
(MOCVD)process. Melas fails to teach or suggest that these
materials are used in any other processes other than MOCVD for
fabricating a semiconductor wafer or that these materials
offer any benefit that is independent of the MOCVD process and
could be carried over into other processes of fabricating
semiconductor wafers. Furthermore, we find that the examiner
has failed to substantiate the allegation that the dopant
species taught by Melas are conventional dopant sources used
in a gas phase doping process.
Accordingly, we find that the examiner’s rejection fails
to point to some teaching, suggestion, or motivation found
either in the prior art relied upon or in knowledge generally
available to one of ordinary skill in the art that would
support using an organic compound like that taught by Melas in
place of the compound taught by Kiyota for directly doping a
semiconductor wafer. In re Fine, 837 F.2d 1071, 1074; 5
USPQ2d 1596, 1598 (Fed. Cir. 1988); In re Jones, 958 F.2d 347,
351; 21 USPQ2d 1941,
1943-44 (Fed. Cir. 1992).
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Turning now to the rejection of claim 49, the examiner
asserts at page 4 of the answer that “Zhang (col. 4, lines 52-
61) teaches to use an organic compound of a dopant species,
and Bohling (col. 10, lines 13-38 and col. 19, lines 33-56)
teaches to use organic compounds of dopant species with a
halogen species for diffusion.”
At page 5 of the answer, the examiner derives therefrom
that “[i]t would have been obvious to one of ordinary skill in
the art at the time the invention was made to use dopant
species as taught by Zhang and Bohling in Kiyota’s process
because the species are well known and conventional dopant
sources during gas phase doping” (emphasis added).
In response, appellant argues at page 8 of the brief the
following three points: (1) that combining Kiyota with Melas
does not produce or render obvious the claimed novel doping
method recited in claim 4; (2) that both Zhang and Bohling
fail to teach the limitation of an organic compound comprising
a halogen species in its molecular structure as required by
claim 49; and (3) that Zhang teaches temperatures no higher
than 550 C. We agree with the examiner that Zhang (col. 4,o
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lines 52-61) teaches the use of an organic compound of a
dopant species in a gas phase process for doping a
semiconductor wafer and that Bohling teaches the use of an
organic compound of a dopant species with a halogen species
for diffusion. However, the examiner’s rejection of claim 49
suffers from the same deficiency mentioned above with respect
to claim 4, that is, the examiner’s rejection again fails to
point to some teaching, suggestion, or motivation found either
in the prior art relied upon or in knowledge generally
available to one of ordinary skill in the art that would
compel a practitioner in the art to replace the compound
taught by Kiyota with the compound taught by Zhang or Bohling
for directly doping a semiconductor wafer. Moreover, it
appears that the examiner’s obviousness rejection hinges
solely on the fact that the compounds are known dopant sources
and are therefore obvious. When the motivation to combine the
teachings of the references is not immediately apparent, it
becomes the duty of the examiner to explain why the
combination of the teachings is proper. Ex parte Skinner, 2
USPQ2d 1788, 1790 (Bd. Pat. App. & Inter. 1986). We do not
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believe that the examiner has properly established motivation
for the suggested combination.
In summary, we will not sustain the examiner’s rejection
of claims 4, 47-52, and 54.
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DECISION
The decision of the examiner is reversed.
REVERSED
)
KENNETH W. HAIRSTON )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
MICHAEL R. FLEMING )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
ANITA PELLMAN GROSS )
Administrative Patent Judge )
KWH:hh
Appeal No. 1999-1666
Application No. 08/847,319
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KAY HOUSTON
TEXAS INSTRUMENTS INCORPORATED
PATENT DEPARTMENT MS 219
PO BOX 655474
DALLAS, TX 75265