Ex Parte Ko et al

Board of Patent Appeals and Interferences

Jul 31, 2006

09894230 (B.P.A.I. Jul. 31, 2006)

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publication in a law journal and is not binding precedent of the Board.

UNITED STATES PATENT AND TRADEMARK OFFICE

________________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
________________

Ex parte FRANCIS KO,
RICHARD CHEN,
and CHARLIE LEE
________________

Appeal No. 2006-0877
Application No. 09/894,230
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ON BRIEF
________________

Before PAK, KRATZ, and JEFFREY T. SMITH, Administrative Patent Judges.

JEFFREY T. SMITH, Administrative Patent Judge.

DECISION ON APPEAL
This is a decision on appeal from the Examiner's final rejection of claims 16 to 24 and
37 to 39, all of the pending claims. We have jurisdiction under 35 U.S.C. § 134.1

1 In rendering this decision we have considered Appellants' arguments presented in the Brief filed June 23, 2005
and the examiner's position presented in the Answer mailed October 17, 2005.
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CITATION OF REFERENCES
In rejecting the claimed subject matter on appeal the Examiner relies on the following
references:
George et al. (George) 4,980,563 Dec. 25, 1990
Kishimura 5,123,998 Jun. 23, 1992
Tsai et al. (Tsai) 5,899,748 May 4, 1999
Young et al. (Young) 6,255,022 B1 Jul. 03, 2001
Sato 6,337,163 B1 Jan. 08, 2002
Schroeder et al. (Schroeder) 6,379,869 B1 Apr. 30, 2002
Rangarajan et al. 6,451,512 B1 Sep. 17, 2002
Singh et al. (Singh) 6,479,820 B1 Nov. 12, 2002

The Examiner entered the following rejections:
(a) claims 16 and 17 stand rejected under 35 U.S.C. § 103(a) over the combined
teachings of Sato, Young, and Schroeder;
(b) claim 18 stands rejected under 35 U.S.C. § 103(a) over the combined teachings of
Sato, Young, Schroeder, and Tsai;
(c) claims 19 to 23 and 37 to 39 stand rejected under 35 U.S.C. § 103(a) over Sato,
Young, Schroeder, Tsai, Kishimura, Singh, and George; and
(d) claim 24 stands rejected under 35 U.S.C. § 103(a) over Sato, Young, Schroeder, and
Rangarajan (Answer, pages 3 to 24).
The invention on appeal relates to a method for increasing the selectivity of a
photoresist. According to Appellants (Brief, page 1), the claimed invention provides for
improved selectivity of silicon-containing photoresist which allows for amelioration of a
subsequent etch profile.
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Application No. 09/894,230

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Representative claim 16, as presented in the Brief, appears below:
16. A method for increasing a selectivity of a photoresist, comprising:

providing a substrate with a developed silicon-containing photoresist
layer disposed over a non-silicon containing photoresist layer, the developed
silicon-containing photoresist layer including polymer chains containing silicon;

exposing the substrate and the developed photoresist layer to an
ultraviolet (UV) light, the UV light emanating from a UV generating agent;

converting a top portion of the developed silicon-containing photoresist
layer to a hardened layer, the hardened layer being created by cross-linking the
polymer chains containing silicon, the cross-linking being activated by the UV
light; and

performing an etch using the hardened layer.

OPINION
Upon careful consideration of the entire record, we find that we are in agreement with
Appellants that the Examiner's rejections are not well founded. We will limit our consideration
to independent claims 16 and 37.
The Examiner determines that Sato discloses a method for improving etching resistance,
i.e., increasing selectivity of an organosilicon photoresist (Answer, pages 3 to 5). The
Examiner in discussing EXAMPLE 1 of Sato identifies the features that are similar to the
present invention. More specifically, Sato discloses the development of an organosilicon
underlying film (12) that contains hardened regions (16). Referring to Figure 1C, the Examiner
explains the resist pattern (14) and the electron beam hardened regions (16) function as etching
masks for dry etching of the unexposed/unhardened regions to form an underlying film pattern
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portion (17) (shown in Figure 1D). Figure 1D clearly exhibits that the hardened area (16)
functions as an etching mask. However, the process of Sato differs from the claimed invention
in that the developed silicon-containing photoresist layer is not disposed over a non-silicon-
containing photoresist layer. The Examiner relies on the Young and Schroeder references for
teaching that persons of ordinary skill in the art would have known that a resist could have been
formed having an organosilicon-containing photoresist layer disposed over a non-silicon-
containing photoresist layer. The Examiner further explains that Young and Schroeder disclose
the hardening/development of the top silicon-containing photoresist layer followed by a
subsequent etching (Answer, pages 6 to 8). The Examiner concludes that a person of ordinary
skill in the art would have found it obvious to form the process of Sato wherein the photoresist
comprised a developed silicon-containing photoresist layer over a non-silicon-containing
photoresist layer in the process of Sato.
Appellants argue that the Young reference is incompatible with the teachings of Sato
and would render Sato unsatisfactory for its intended purpose (Brief, pages 6 and 7). We agree.
While it may be known, as suggested by the Examiner, that a photoresist could be
formed comprising a silicon-containing organosiloxane over a non-silicon-containing
organosiloxane, this does not indicate that such structure would be suitable for the invention of
Sato.2 Specifically, Sato requires the underlying film to be a material whose etch rate is

2 We note that Appellants have not argued that it was not known to develop a
silicon-containing photoresist layer, or that the formation of a photoresist
comprising a silicon-containing photoresist layer over a non-silicon-
containing photoresist layer would not have been obvious (see Brief
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lowered by the irradiation of a charge beam (see column 5, lines 53-62). As such, if the
Examiner's exchange of the order of layers of Sato were achieved the resulting structure would
not meet the requirements as specified by Sato. Accordingly, we agree with Appellants'
argument (Brief, page 7) that the suggested modification would render Sato unsatisfactory for
its intended purpose.
In view of the foregoing, the Examiner has failed to establish a prima facie case of
obviousness to support the stated rejections. The Federal Circuit has held that "[i]t is
impermissible to use the claimed invention as an instruction manual or 'template' to piece
together the teachings of the prior art so that the claimed invention is rendered obvious." In re
Fritch, 972 F.2d 1260, 1266, 23 USPQ2d 1780, 1784 (Fed. Cir. 1992). Consequently, the
rejections of the Examiner are reversed.

generally). Appellants have also not argued that the developed/hardened
portion of a silicon-containing photoresist layer does not function as an
etch mask as suggested by the Examiner.
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Application No. 09/894,230

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REVERSED

CHUNG K. PAK
Administrative Patent Judge )
)
)
)
)
PETER F. KRATZ ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
)
JEFFREY T. SMITH )
Administrative Patent Judge )

JTS:clm

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Application No. 09/894,230

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