Ex parte Kusunoki et al.

Board of Patent Appeals and Interferences

Jul 16, 2001

08622327 (B.P.A.I. Jul. 16, 2001)

1 Application for patent filed March 26, 1996.
1
The opinion in support of the decision being entered today was not written for
publication in a law journal and is not binding precedent of the Board.
Paper No. 29
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte SHIGERU KUSUNOKI and
HIDEKAZU ODA
_____________
Appeal No. 1998-0088
Application 08/633,3271
______________
ON BRIEF
_______________
Before THOMAS, MARTIN, and FLEMING, Administrative Patent Judges.
MARTIN, Administrative Patent Judge.
DECISION ON APPEAL
Appeal No. 1998-0088
Application 08/622,327
2 Paper No. 17.
3 Claims 2 and 17-20 were indicated as allowed, claims 5 and 6
were indicated as objected to for depending from rejected claims, and
claim 9 was indicated as canceled.
2
This appeal was taken from the October 24, 1996, Office action2
finally rejecting claims 1, 3, 4, 7, 8, 10, 11, and
15-16. We reverse and remand.
. Reasons for the remand
In the final Office action, the foregoing claims were rejected
on the following grounds:3
(a) claim 8 under 35 U.S.C. § 112, first paragraph;
(b) claims 10 and 11 under § 112, second paragraph;
(c) claims 15 and 16 under § 102(b) for anticipation by, and
alternatively under § 103 for obviousness over, Fujii et al. (Fujii);
(d) claims 1 and 3 under § 103 for obviousness over Kusunoki et
al. (Kusunoki);
(e) claims 1, 3, and 4 under § 103 for obviousness over
Kusunoki in view of Shinada et al. (Shinada);
(f) claims 7, 8, 10, 11, 15, and 16 under § 103 for obviousness
over Yamauchi et al. (Yamauchi) in view of Fujii; and
Appeal No. 1998-0088
Application 08/622,327
4 Paper No. 20.
5 Paper No. 19.
3
(g) claims 7, 8, 10, 11, 15, and 16 for obviousness-type double
patenting in view of claims 1 and 2 of Patent 5,369,297.
On January 2, 1997, appellants filed an amendment after final4
pursuant to 37 CFR § 1.116 and on January 9, 1997, filed a terminal
disclaimer5 to obviate the double patenting rejection.
In an Advisory Action mailed January 27, 1997, the examiner
indicated that the amendment after final would be entered upon the
filing of an appeal and would be effective to overcome the rejection
of claims 10 and 11 on reference grounds and the rejections of claims
8, 10, and 11 on non-reference grounds.
In the Answer (at 1) the examiner, citing the persuasiveness of
appellants' arguments at pages 12-17 of the Brief concerning the §
103 rejection of claims 1 and 3 based on Kusunoki and the § 103
rejection of claims 1, 3, and 4 based on Kusunoki in view of Shinada,
the examiner withdrew the rejections of claims 1, 3, and 4. Also,
citing the persuasiveness of some of the arguments at pages 17-19 of
the Brief, wherein appellants discussed the § 103 rejection of claims
7, 8, 15, and 16 based on Yamauchi in view of Fujii, the examiner
Appeal No. 1998-0088
Application 08/622,327
4
withdrew that ground of rejection only with respect to claims 7 and 8
(Answer at 1). As a result, the failure of the Answer to repeat that
ground of rejection with respect to claims 15 and 16 or to address
appellants' arguments directed thereto appears to have been an
oversight on the examiner's part, which the examiner is invited to
correct on remand in a Second Supplemental Examiner's Answer.
Accordingly, this application is remanded to the examiner to correct
this apparent oversight.
B. The invention
Appellants' application discloses a number of embodiments of
nonvolatile semiconductor memory devices employing transistors having
nitrided oxide films. The Figure 1 embodiment includes two types of
such films. Film 22, referred to as a nitrided oxide (NO) film,
contains nitrogen at a content not less than 2.5x1020/cm3 and hydrogen
at a content of 3x1020/cm3 or more (Spec. at 18, ll. 10-13). Film 22
overlies the channel hot electron (hole) carrier injection region 20
in order to increase the injection efficiency of the channel hot
electrons (Spec. at 18, ll. 15-17 and at 19, ll. 13-16). This
improves the writing efficiency without increasing the drain and gate
Appeal No. 1998-0088
Application 08/622,327
5
voltages, thereby permitting the writing operation to be performed at
a high speed even with a low voltage supply (Spec. at 19,
ll. 16-20).
Film 12, referred to as a re-oxidized nitrided oxide (RNO)
film, contains nitrogen at a content not less than 2.5x1020/cm3 and
hydrogen at a content less than 3x1020/cm3 (Spec. at 18, ll. 2 and 8-
10). Film 12 overlies the drain avalanche hot carrier injection
region 10 in order to suppress the injection of drain avalanche hot
carriers (Spec. at 18, ll. 17-19 and at 19, ll. 21-25). As a result,
even if the electric field near the drain region 7 increases due to
miniaturization, generation of an interface level due to implantation
of drain avalanche hot carriers can be effectively prevented (Spec.
at 19, l. 25 to p. 20, l. 5).
In addition to the embodiment depicted in Appellants' Figure 1,
the drawings show ten other embodiments (Spec. at 15-16).
C. The claims
Claim 15, the sole independent claim on appeal, reads as
follows:
15. A semiconductor memory device comprising:
a semiconductor substrate; and
Appeal No. 1998-0088
Application 08/622,327
6
a single transistor comprising:
a source region and a drain region formed on said main
surface of said semiconductor substrate with a predetermined
space between each other and are located at opposite sides of a
channel region;
a nitrided oxide film formed at least at a drain
avalanche hot carrier injection region on said main
surface of said semiconductor substrate, and containing
nitrogen at a content not less than 2.5x1020/cm3 and
hydrogen at a content less than 3x1020/cm3;
a gate electrode formed on said channel region; and
a silicon oxide film formed on said channel region
continuous to said nitrided oxide film.
In view of the way the term "continuous to" is used in the
specification (see page 18, lines 5-7, page 25, lines 15-17, page 35,
lines 22-24, page 40, lines 8-10, page 41, lines 4-5, and page 41,
lines 3-4), that term is understood to mean "in direct contact with."
Claim 15 recites a silicon oxide formed on the channel region
continuous to a nitrided oxide film having a nitrogen content not
less than 2.5x1020/cm3 and a hydrogen content less than 3x1020/cm3),
which as noted above is referred to in the specification as an RNO
Appeal No. 1998-0088
Application 08/622,327
6 Claim 15 does not also require a nitrided oxide of the NO
type.
7 Paper No. 17.
7
film (12 in Figure 1).6 Consequently, claim 15 reads on the "eighth"
embodiment shown in Figure 44, which includes a silicon oxide film 2d
that is located between and in direct contact with RNO films 12d.
D. The reference and rejections
The only rejections argued in the answer are based on the
following reference:
Fujii et al. (Fujii) 5,063,423 Nov. 5, 1991
Claims 15 and 16 stand rejected under § 102 as anticipated by
Fujii and, alternatively, under § 103 for obviousness over Fujii.
E. The merits of the rejections
The examiner contends that claims 15 and 16 are anticipated by
the semiconductor device shown in Fujii's Figures 1A-1G.
Specifically, in the Final Office action7 the examiner reads the
claimed nitrided oxide film on tunneling layer 14, which the examiner
describes as located over drain region 13 and continuous with the
silicon dioxide layer 17. The examiner further contends that the
claimed nitrogen content is shown in Figures 12A-12C and that the
Appeal No. 1998-0088
Application 08/622,327
8
claimed hydrogen content "is considered to be inherent in the RNO
tunneling layer 14 of Fujii et al. or obvious to one of ordinary
skill in the art since Fujii et al. teach that eliminating nonreacted
hydrogen and hydrogen compounds from the film is desirable to prevent
film breakdown" (Final Office action at 4).
We are reversing the rejection because we agree with appellants
that the examiner has not cited any evidence which prima facie
establishes that Fujii's tunneling layer 14, which is located
entirely over and near the center of drain region 13, is located "at
least at a drain avalanche hot carrier injection region on said main
surface of said semiconductor substrate," as required by claim 15.
In fact, the location requirement in this limitation is not even
addressed by the examiner, who argues with respect to this
limitation only that Fujii's device inherently includes a drain
avalanche hot carrier injection region (Answer at 5). The examiner's
failure to explain why the claimed location requirement is inherently
satisfied fails to satisfy the PTO's initial burden of proof when
arguing inherency. Cf. In re King, 801 F.2d 1324, 1326, 231 136, 138
(Fed. Cir. 1986) (where the Patent Office has reason to believe that
a functional limitation asserted to be critical for establishing
Appeal No. 1998-0088
Application 08/622,327
9
novelty in claimed subject matter may, in fact, be an inherent
characteristic of the prior art, it possesses the authority to
require the applicant to prove that the subject matter shown to be in
the prior art does not possess the characteristic relied on). While
not argued by the examiner, we note that even if Fujii's description
of layer 14 as a "tunneling" layer and reference to "electron
injection" at column 1, line 49 can be understood to mean that
electrons are injected from drain 13 through tunneling layer 14 to
floating gate 181 (Fig. 1G; col. 4, ll. 45-46), it does not follow
that the injected electrons inherently are "avalanche" carriers, as
required by claim 15. In fact, such a conclusion is contrary to
appellants' disclosure. In Appellants' Figure 1 embodiment, the
drain avalanche hot carrier injection region 10 is located within the
channel region 35 and adjacent to the junction of the channel region
and drain 7. Thus, a drain avalanche hot carrier injection region
developing in the corresponding location in Fujii's device would not
Appeal No. 1998-0088
Application 08/622,327
8 Min-Liang Chen et al., "Suppression of Hot-Carrier Effects in
Submicrometer CMOS Technology," 35 IEEE Transactions on Electron
Devices 2210-20 (December 1998), of which a copy was provided with
the Brief, shows (at 2211, Fig. 1) that the drain avalanche hot
carrier injection region is located within the channel region and
adjacent to the lightly doped (N-) drain region when the drain
includes a lightly doped (N-)region and a heavily doped (N+) region,
which is not the case in Fujii's device. The positional relationship
shown in Chen et al. also appears in appellants' Figure 20 (Spec. at
29, l. 21 to p. 30, l. 3).
10
lie under Fujii's tunneling layer 14, as in necessary for Fujii to
inherently satisfy claim 15.8
For the foregoing reasons, we are reversing the § 102(b)
rejection of claims 15 and 16 for anticipation by Fujii.
We are reversing the § 103 rejection of claims 15 and 16 based
on Fujii because the examiner has not explained how or why it would
have been obvious to modify Fujii's device in order to satisfy the
requirement that the nitrided oxide layer be at least at the drain
avalanche hot carrier injection region.
This decision contains a new ground of rejection pursuant to
37 CFR § 1.196(b) (amended effective Dec. 1, 1997, by final rule
notice, 62 Fed. Reg. 53,131, 53,197 (Oct. 10, 1997), 1203 Off. Gaz.
Pat. & Trademark Office 63, 122 (Oct. 21, 1997)). 37 CFR
Appeal No. 1998-0088
Application 08/622,327
11
§ 1.196(b) provides, "[a] new ground of rejection shall not be
considered final for purposes of judicial review."
37 CFR § 1.196(b) also provides that the appellants, WITHIN TWO
MONTHS FROM THE DATE OF THE DECISION, must exercise one of the
following two options with respect to the new ground of rejection to
avoid termination of proceedings (37 CFR § 1.197(c) as to the
rejected claims:
(1) Submit an appropriate amendment of the claims so
rejected or a showing of facts relating to the claims so
rejected, or both, and have the matter reconsidered by the
examiner, in which event the application will be remanded
to the examiner . . . .
(2) Request that the application be reheard under
§ 1.197(b) by the Board of Patent Appeals and
Interferences upon the same record . . . .
Appeal No. 1998-0088
Application 08/622,327
12
No time period for taking any subsequent action in connection
with this appeal may be extended under 37 CFR
§ 1.136(a).
REVERSED; 37 CFR § 1.196(b)
JAMES D. THOMAS )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
JOHN C. MARTIN ) APPEALS AND
Administrative Patent Judge ) INTERFERENCES
)
)
)
MICHAEL R. FLEMING )
Administrative Patent Judge )
JCM/sld
Appeal No. 1998-0088
Application 08/622,327
13
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