Ex Parte Mui et al

Board of Patent Appeals and Interferences

Jul 25, 2007

09905172 (B.P.A.I. Jul. 25, 2007)

The opinion in support of the decision being entered today was not written
for publication and is not binding precedent of the Board.

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte DAVID S. MUI, WEI LIU, THORSTEN LILL,
CHRISTOPHER DENNIS BENCHER,
and YUXIANG MAY WANG
____________

Appeal 2007-0706
Application 09/905,172
Technology Center 1700
____________

Decided: July 25, 2007
____________

Before CHUNG K. PAK, CATHERINE Q. TIMM, and
JEFFREY T. SMITH, Administrative Patent Judges.

PAK, Administrative Patent Judge.

DECISION ON APPEAL
This is a decision on an appeal from the Examiner's final rejection of
claims 8 through 11, 13, and 15 through 40, all of the claims pending in the
above-identified application. We have jurisdiction pursuant to 35 U.S.C. §§
6 and 134.
Appeal 2007-0706
Application 09/905,172

STATEMENT OF THE CASE
The subject matter on appeal is directed to anti-reflection coatings and
hard masks for use in defining etch patterns within an underlying substrate
structure. (Specification 1). Further details of the appealed subject matter
are recited in representative claim 8 reproduced below:
8. A method of forming a multilayer antireflective hard mask
structure, said method comprising:

providing a substrate structure;

depositing a CVD organic layer over said substrate structure by a
plasma enhanced chemical vapor deposition process using a feed stream that
comprises a hydrocarbon species, said CVD organic layer comprising
carbon and hydrogen;

depositing a dielectric layer over said CVD organic layer;

providing a patterned organic photoresist layer over said dielectric
layer;

etching said dielectric layer through apertures in said patterned
photoresist layer in a first plasma etching step until apertures are formed in
said dielectric layer; and

etching said CVD organic layer through said apertures in said
dielectric layer in a second plasma etching step until apertures are formed in
said CVD organic layer.

As evidence of unpatentability of the claimed subject matter, the
Examiner has relied upon the following prior art references:
Cheng US 5,873,984 Feb. 23, 1999
Chapman US 5,976,769 Nov. 2, 1999
Tsai US 6,083,815 Jul. 4, 2000
Huang US 6,171,940 B1 Jan. 9, 2001
Lou US 6,200,881 Mar. 13, 2001
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Hasegawa US 6,452,274 B1 Sep. 17, 2002

The Examiner has rejected the claims on appeal as follows:
1. Claims 8 through 11, 13, 15 through 21, and 27 through 29
under 35 U.S.C. § 103(a) as unpatentable over the combined disclosures of
Huang and Hasegawa;
2. Claims 22 through 24 under 35 U.S.C. § 103(a) as unpatentable
over the combined disclosures of Huang, Hasegawa, and Tsai;
3. Claims 25 and 26 under 35 U.S.C. § 103 as unpatentable over
the combined disclosures of Huang, Hasegawa, and Lou;
4. Claims 30, 31, 33, and 34 under 35 U.S.C. § 103(a) as
unpatentable over the combined disclosures of Huang, Hasegawa, and
Chapman; and
5. Claims 14, 32, and 35 through 40 under 35 U.S.C. § 103(a) as
unpatentable over the combined disclosures of Huang, Hasegawa, and either
Cheng or Chang and Chapman.
IV. ISSUE
Has the Examiner demonstrated that a person having ordinary skill in
the art would have been led to employ the CVD (chemical vapor deposition)
of the low dielectric organic material disclosed in Hasegawa as the low
dielectric organic material taught by Huang in Huang’s semiconductor
making process within the meaning of 35 U.S.C. § 103?

V. RELEVANT FACTUAL FINDINGS
1. The Examiner has found, and the Appellants have not disputed, that:
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Application 09/905,172

Huang describes a method for forming a semiconductor device
comprising: providing a substrate structure; forming an organic
layer with low dielectric constant over the substrate; depositing
a dielectric layer, SiON, over the organic layer; providing a
patterned photoresist (claimed organic photoresist: please see
cited art below) over the dielectric layer; etching the dielectric
layer with dry etch (claimed first plasma etching) until
apertures are formed in the dielectric layer; etching the organic
layer using an anisotropic etching (claimed second plasma
etching) until apertures are formed in the organic layer (col. 2,
line 47-co1. 3, line 17). (Compare Answer 3 with Brief and
Reply Brief in their entirety.)
2. According to the Appellants at page 6 of the Brief:
Huang describes a semiconductor device and method of
formation thereof. The device has a semiconductor substrate,
an insulating layer, which may be organic, thereon, a dielectric
layer thereon and a patterned photoresist thereon. The
insulating layer is not described as comprising carbon and
hydrogen and is not deposited by CVD. In fact there is no
disclosure of any specific organic material.
3. Huang’s organic layer with low dielectric constant is known to
provide an insulation function (referred to by the Appellants as an insulation
layer), but is not said to contain carbon and hydrogen and is not said to be
deposited by CVD. (Compare Answer 3 with Brief 6.)
4. Hasegawa describes employing an organic layer with low dielectric
constant comprising carbon and hydrogen as an insulation layer in producing
a semiconductor device. (Compare Answer 3, with Brief 6.)
5. Hasegawa teaches (col. 9, ll. 4-12) that:
The dielectric layer can be formed, for example, by forming a
precursor of the polymer by a spin coater and then baking at
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Application 09/905,172

300 to 500oC. In the case of a material such as amorphous
carbon, the dielectric layer may be formed by using acetylene
[carbon and hydrogen containing organic material] or, if
necessary, a fluorocarbon gas and using a plasma enhanced
CVD system.
6. The Appellants have not challenged the Examiner’s official notice at
page 8 of the Answer that “the CVD method is known to one skilled in the
art at the time of the invention to deposit material[s] such as organic layer[s],
used by Huang.” (Compare Answer 8, with Br. in its entirety).
7. Huang discloses that one possible object of the invention is to use the
low dielectric organic material for a purpose “analogous to a hard mask.”
(Col 1, ll. 48-51 and Col. 3, ll. 15-25).
8. Huang, by virtue of not specifically mentioning the names of low
dielectric organic materials and deposition techniques, leaves one of
ordinary skill in the art to appropriately choose conventional low dielectric
organic (insulation) materials and deposition techniques. (Col. 2, ll. 49-65).
Implicit in this teaching is that the selection of appropriate (known) low
dielectric organic (insulation) materials and (known) deposition techniques
is well within the ambit of one of ordinary skill in the art.
VI. PRINCIPLE OF LAW
Under 35 U.S.C. § 103, the factual inquiry into obviousness requires a
determination of: (1) the scope and content of the prior art; (2) the
differences between the claimed subject matter and the prior art; (3) the level
of ordinary skill in the art; and (4) secondary consideration (e.g., the
problem solved). Graham v. John Deere Co. of Kansas City, 383 U.S. 1,
17-18, 148 USPQ 459, 467(1966). “[A]nalysis [of whether the subject
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matter of a claim is obvious] need not seek out precise teachings directed to
the specific subject matter of the challenged claim, for a court can take
account of the inferences and creative steps that a person of ordinary skill in
the art would employ.” KSR Int’l v. Teleflex, Inc., 127 S. Ct. 1727, 1740-41,
82 USPQ2d 1385, 1396 (2007) quoting In re Kahn, 441 F.3d 977, 988, 78
USPQ2d 1329, 1336-37 (Fed. Cir. 2006); see also DyStar Textilfarben
GmBH & Co. Deutschland KG v. C.H. Patrick Co., 464 F.3d 1356, 1361, 80
USPQ2d 1641, 1645 (Fed. Cir. 2006)(“The motivation need not be found in
the references sought to be combined, but may be found in any number of
sources, including common knowledge, the prior art as a whole, or the
nature of the problem itself.”); In re Bozek, 416 F.2d 1385, 1390, 163 USPQ
545, 549 (CCPA 1969)(“Having established that this knowledge was in the
art, the examiner could then properly rely, as put forth by the solicitor, on a
conclusion of obviousness ‘from common knowledge and common sense of
the person of ordinary skill in the art without any specific hint or suggestion
in a particular reference.’”); In re Hoeschele, 406 F.2d 1403, 1406-07, 160
USPQ 809, 811-812 (CCPA 1969) (“[I]t is proper to take into account not
only specific teachings of the references but also the inferences which one
skilled in the art would reasonably be expected to draw therefrom . . .”).
VII. ANALYSIS
The Examiner’s rejections all hinge upon the combinability of
primary reference Huang and secondary reference Hasegawa as the
Appellants’ arguments are limited to these two references. In essence, the
Appellants only contend that one of ordinary skill in the art would not have
been led to employ the claimed CVD organic layer as the organic layer of
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the semiconductor taught by Huang. The dispositive question is, therefore,
whether the use of Hasegawa’s organic material having low dielectric
constant (used as an insulation layer) as the low dielectric organic material
(admittedly known insulation material) in Huang’s process would have been
obvious to a person of ordinary skill in the art. On this record, we answer
this question in the affirmative.
Here, Huang teaches a method for forming a semiconductor device
comprising: a substrate structure; forming an organic layer with a low
dielectric constant over the substrate; depositing a dielectric layer (SiON),
over the organic layer; providing a patterned photoresist over the dielectric
layer; etching the dielectric layer with dry etch (claimed first plasma
etching) until apertures are formed in the dielectric layer; and etching the
organic layer using an anisotropic etching (claimed second plasma etching)
until apertures are formed in the organic layer. (Compare Answer 3 with Br.
and Reply Br. in their entirety). As stated by the Appellants, “[t]he
insulating [low dielectric organic] layer [of Huang] is not described as
comprising carbon and hydrogen and is not deposited by CVD. In fact there
is no disclosure of any specific organic material [and any deposition
technique].” (Br. 6). Rather, Huang leaves one of ordinary skill in the art to
conventionally deposit appropriate (known) low dielectric organic materials
(admittedly known insulation materials in a semiconductor device).
Hasegawa describes conventional low dielectric organic materials (used as
an insulation layer for a semiconductor device), some of which contain
carbon and hydrogen (col. 3, l. 45 to col. 4, l. 28, col. 1, ll. 9-10, and 8. l. 66
to col. 9, l. 12). See, e.g., Merck & Co. v. Biocraft Laboratories, Inc., 874
F.2d 804, 807, 10 USPQ2d 1843, 1846 (Fed. Cir.) cert. denied, 493 U.S. 975
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(1989). Hasegawa teaches conventional deposition techniques, including
CVD (col. 8, l. 66 to col. 9, l. 12). Moreover, there is no dispute that CVD is
a known technique for depositing an organic insulation layer on a
semiconductor substrate. (Compare Answer 8, with Br. and Reply Br. in
their entirety).
Given that the selection of appropriate low dielectric organic
(insulation) layers, including the claimed conventional low dielectric organic
layer, and appropriate deposition techniques, including known CVD, is well
within the ambit of one of ordinary skill in the art, we concur with the
Examiner that one of ordinary skill in the art would have been led to employ,
inter alia, the claimed CVD organic layer as the organic layer in Huang’s
process, motivated by a reasonable expectation of successfully forming the
semiconductor device taught by Huang. KSR Int’l Co. v. Teleflex, Inc., 127
S. Ct. at 1739, 82 USPQ2d at 1395 (“The combination of familiar elements
according to known methods is likely to be obvious when it does no more
than yield predictable results.”); Hoeschele, 406 F.2d at 1406-07, 160 USPQ
at 811-812 (“[I]t is proper to take into account not only specific teachings of
the references but also the inferences which one skilled in the art would
reasonably be expected to draw therefrom . . .”).
In reaching this determination, we are cognizant of the Appellants’
arguments which appear to be directed to the claimed preamble limitation
“forming a multilayer antireflective hard mask structure.” (Br. 2).
However, as indicated supra, Huang and Hasegawa would have taught or
suggested forming the claimed multilayer structure in the claimed manner
(i.e., employing the claimed process steps). Moreover, Huang discloses that
one possible object of the invention is to use the low dielectric organic
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material over a polysilicon layer “analogous to a hard mask.” (Col. 1, ll. 48-
51 and Col. 3, ll. 15-25). However, on this record, the Appellants have not
demonstrated that the claimed preamble limitation renders the claimed
process steps materially different from those taught and/or suggested by the
prior art references.
In view of the foregoing, we determine that the Examiner has
established a prima facie case of obviousness and the Appellants have not
sufficiently rebutted the prima facie case.

VIII. ORDER
Accordingly, the decision of the Examiner is affirmed.
No time period for taking any subsequent action in connection with
this appeal maybe extended under 37 C.F.R. § 1.136(a)(1)(iv).

AFFIRMED

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