Ex Parte Lindfors

Board of Patent Appeals and Interferences

Mar 17, 2010

10615332 (B.P.A.I. Mar. 17, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte SVEN LINDFORS
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Appeal 2009-013982
Application 10/615,332
Technology Center 1700
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Decided: March 17, 2010
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Before CHARLES F. WARREN, TERRY J. OWENS, and
MARK NAGUMO, Administrative Patent Judges.

NAGUMO, Administrative Patent Judge.

DECISION ON APPEAL
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Application 10/615,332

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A. Introduction1, 2
Sven Lindfors (“Lindfors”) timely appeals under 35 U.S.C. § 134(a)
from the final rejection3 of claims 12-17, 19-26, and 30-34. We have
jurisdiction under 35 U.S.C. § 6. We AFFIRM.
The subject matter on appeal relates to methods of depositing films on
semiconductor wafers, particularly by atomic layer deposition (“ALD”).
According to Lindfors, many of the reactants used in ALD are low-vapor
pressure liquids that require heating to high temperatures to obtain
significant vaporization. Once vaporized, the materials must be maintained
at high temperatures to prevent condensation before they react with other
components and form films on the intended substrate. Because the high
temperatures can accelerate thermal decomposition of the low-vapor
pressure liquids, and because the dose introduced to the reaction chamber
must be controlled carefully, it is desirable to limit the amount of liquid that
is vaporized. Moreover, because the reactants are typically mutually very
reactive, even at room temperature, it is important to keep the different
reactants confined to the reaction chamber, to introduce them separately, and
to keep them apart from one another elsewhere in the apparatus.

1 Application 10/615,332, Method and Apparatus for the Pulse-Wise Supply
of a Vaporized Liquid Reactant, filed 8 July 2003, claiming the benefit of a
provisional application filed 12 July 2002. The specification is referred to as
the “332 Specification,” and is cited as “Spec.” The real party in interest is
listed as ASM International N.V. (Appeal Brief, filed 23 February 2009
(“Br.”), 3.)
2 The oral argument scheduled for 11 March 2010 was waived.
3 Office action mailed 15 July 2008 (“Final Rejection”; cited as “FR”).
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To accomplish these goals, the two or more reactants are introduced in
alternating pulses to the reaction chamber. The production of alternating
pulses involves sophisticated schemes such as “inert gas valving,” in which
inert gases are used to create “inert gas diffusion barriers” by establishing
higher pressures in certain gas lines of the apparatus to keep gases in lower
pressure regions from invading the higher pressure regions.
Lindfors claims a method in which a liquid precursor, typically held at
ambient temperature in a storage chamber, is introduced to a vaporization
chamber at a higher temperature. The vapor is then introduced to a reaction
chamber, in alternating pulses with another reactant, to deposit a film on a
substrate. Unevaporated liquid in the evaporating chamber is then returned
to the storage chamber, whence it can be used in a subsequent vaporization
and reaction-deposition cycle.
Representative Claim 12 is reproduced from the Claims Appendix to
the Principal Brief on Appeal, with labels to Figure 1 of Lindfors’s
supporting 332 Specification (reproduced below at 7) added to illustrate—
but not to limit—the claimed invention:
12. A method for providing vapor phase reactant from solid
or liquid source, comprising:
supplying a liquid comprising a precursor from a storage
container [100] to a vaporization chamber [312];
maintaining the vaporization chamber [312] at a higher
temperature [T2] than the storage container [100];
vaporizing the precursor in the vaporization chamber;
transporting the vaporized precursor to a reaction
chamber [410];
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conducting a vapor deposition process using the
vaporized precursor in the reaction chamber;
draining unvaporized liquid from the vaporization
chamber [310] after conducting the vapor deposition
process without opening the vaporization chamber;
returning the unvaporized liquid to the storage
container [100]; and
returning the unvaporized liquid to the vaporization
chamber
wherein transporting comprises
supplying pulses of the vaporized precursor to the
reaction chamber alternatingly with pulses of at
least one other precursor and
stopping and allowing flow of the vaporized
precursor from the vaporization chamber to the
reaction chamber with an inert gas diffusion
barrier and wherein stopping and allowing flow
with an inert gas diffusion barrier comprises
controlling valves for an inert gas flow
outside of a hot zone accommodating the
vaporization chamber.
(Claims App., Br. 17; indentation, paragraphing, emphasis, and bracketed
labels added.)4
The Examiner has maintained the following grounds of rejection:5
A. Claims 12-14, 19-23, 26, and 30 stand rejected under
35 U.S.C. § 103(a) in view of the combined teachings of
Murakami,6 Modisette,7 and Bondestram.8

4 Labels are shown in bold font throughout, for clarity, regardless of their
presentation in the original document.
5 Examiner’s Answer mailed 28 April 2009. (“Ans.”).
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B. Claims 15 and 16 stand rejected under
35 U.S.C. § 103(a) in view of the combined teachings of
Murakami, Modisette, Bondestram, and Kaloyeros.9
C. Claims 17, 31, and 32 stand rejected under
35 U.S.C. § 103(a) in view of the combined teachings of
Murakami, Modisette, Bondestram, Kaloyeros, and
Sturm.10
D. Claims 24 and 25 stand rejected under
35 U.S.C. § 103(a) in view of the combined teachings of
Murakami, Modisette, Bondestram, and Van Buskirk.11
E. Claims 33 and 34 stand rejected under
35 U.S.C. § 103(a) in view of the combined teachings of
Murakami, Modisette, Bondestram, and Gauthier.12
Lindfors contends there is no reason in the references to modify the
structure described by Murakami and to use the modified structure to return
liquid reactants from evaporator 8 to reservoir 4. (Br. 12.) According to
Lindfors, Murakami is concerned with reactants clogging the liquid supply
lines, and therefore teaches away from returning reactants to the reservoir.
(Br. 11, first full para.) Lindfors argues that Modisette does not cure this

6 Seishi Murakami and Tatsuo Hatano, Liquid Material Supply Apparatus
and Method, U.S. Patent 6,126,994 (2000).
7 Jerry L. Modisette and Otto F. Schkade, Vapor Recovery System and
Method, U.S. Patent 3,981,156 (1976).
8 Niklas Bondestram and Menso Hendriks, Active Pulse Monitoring in a
Chemical Reactor, U.S. Patent 7,063,981 B2 (2006) based on an application
filed 30 January 2002.
9 Alain E. Kaloyeros et al., U.S. Patent 5,476,409 (1994).
10 Edward A. Sturm et al., U.S. Patent 6,178,925 B1 (2001).
11 Peter C. Van Buskirk et al., U.S. Patent 5,882,416 (1999).
12 Scott Gautier, U.S. Patent 6,007,330 (1999).
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deficiency because Modisette teaches condensing vapor from a storage tank
by processes, presumably in the presence of air, that are returned to the
storage tank. Because the contact with air is the specific problem that
Murakami seeks to avoid, Lindfors argues, “the combination [with
Murakami] does not work.” (Br. 13, first para.)
The Examiner maintains that it would have been obvious to adapt the
liquid delivery system described by Murakami to perform the ALD process
described by Bondestram. (FR 6.) According to the Examiner, the
difference between the claimed process and such a process is that Murakami
directs unvaporized low-vapor pressure liquid remaining in the evaporator to
a cold trap, rather than recycling the unevaporated liquid to the initial
storage container. (Id. at 5.) Modisette, in the Examiner’s view, shows that
the re-use of materials is well-known in the chemical arts. (Id.) Moreover,
according to the Examiner, the structures described by Murakami are
capable of being used to perform the claimed method. (Id. at 2.) Thus, the
Examiner concludes, it would have been obvious to modify the apparatus
described by Murakami to return the unevaporated low vapor pressure liquid
to the reservoir, while performing an ALD process as described by
Bondestram. (Id. at 6.)
The dispositive issues in this case are whether Lindfors has shown
that Murakami teaches away from recycling the unevaporated liquid left in
evaporator 8; and whether the Examiner’s reliance on Modisette is faulty.
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B. Findings of Fact
Findings of fact throughout this Opinion are supported by a
preponderance of the evidence of record.
The 332 Specification
The disputed portions of the appealed method are readily understood
with reference to Figure 1 from the 332 Specification, which is reproduced
below:

{Figure 1 is said to show an apparatus}
In the claimed process, storage container 100 is charged with liquid
reactant 102. (Spec. 8, ¶ [0025].) The remainder of the container 104 is
filled with inert gas via feed line 110. Upon pressuring storage
container 100 with inert gas, liquid reactant 312 is advanced into
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vaporization chamber 310 via transfer line 124. (Id.) Vaporization
chamber 312 is held in hot zone 300 at temperature T2, which is higher than
the ambient temperature T1 of the storage container. (Id. at ¶ [0026].)
Vaporized reactant 314 collects above the unvaporized liquid 312, and is
introduced to reaction chamber 410 in hot zone 400 by a pulse of inert gas
passed through pulse valve 138 in inert gas supply line 136. (Id.
at 9, ¶ [0029]-10, ¶ [0030].) Details of the inert gas diffusion barrier are not
necessary to understanding this appeal. Similarly, the mechanisms for
generating the alternating pulses of the other reactant, which are not shown
in the Figures, are not necessary to resolve this appeal.
According to the 332 Specification, vaporization chamber 310 can be
drained at any suitable time (Spec. 9, ¶ [0028]) by setting appropriate valves
and raising the pressure in vaporization chamber 310 above the pressure in
storage chamber 100, which may be evacuated by vacuum pump 116
(Id. at 8-9, ¶ [0027]).
Murakami
Murakami describes an apparatus and method for providing a low
vapor pressure liquid material via an evaporation chamber to a film
deposition chamber. (Murakami, Abstract; col. 2, ll. 34-52.) In Murakami’s
words, “[t]he deposition chamber 30 is applicable to any deposition
apparatus.” (Id. at col. 4, ll. 38-39.) Murakami does not mention atomic
layer deposition processes or apparatuses.
According to Murakami, the liquid materials used for making films
typically have low vapor pressures and are very reactive and are readily
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oxidized upon contact with air. (Murakami, col. 1, ll. 43-50.) Heating is
said to provide the needed amount of vapor, but also to cause thermal
decomposition problems. Moreover, reaction of residual liquid materials in
pipes and connections with oxygen is said to “produce solid byproducts on
replacement of liquid tanks,” which clogs those pipes and connections. (Id.
at col. 2, ll. 11-13.) Yet another problem is said to arise because the amount
of liquid needed to provide the desired mount of gas is very small, making it
“very difficult to supply stably and accurately the low vapor pressure liquid
materials from the liquid tank to the deposition chamber.” (Id. at col. 2,
ll. 23-25.)
Murakami provides an apparatus, shown in Figure 1, reproduced
below, and processes of using the apparatus, that are said to address these
problems.

{Murakami Figure 1 is said to show an apparatus}
Low vapor pressure liquid L in reservoir 4 is moved, under pressure of
helium gas provided via line 10, through discharge nozzle 20 and lines 24B
and 24A to evaporator 8. (Murakami, col. 4, ll. 6-32.) The transfer lines and
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the evaporation chamber are heated by heaters 68 and 70. (Id. at col. 5,
ll. 56-67.) The liquid is vaporized, and the vapor then moved to reactor 30
via line 34 under helium pressure provided via line 38. (Id. at col. 4,
ll. 34-38.)
According to Murakami, “evaporator 8 of this type has a dead
space 50[13] unavoidably formed by its structure.” (Murakami, col. 5,
ll. 10-11.) As a result, residual liquid collets in the dead space 50, and when
the next deposition cycle starts, the residual liquid is vaporized and
deposited on the substrate, in addition to the liquid transferred deliberately
from reservoir 4. As a result, too much material is provided, and proper
films cannot be deposited on the wafers. (Id. at ll. 15-21.) To solve this
problem, Murakami provides discharge passage 54A, which permits the
residual liquid to be discharged via line 52 to cold trap 60. (Id. at ll. 26-40
and at col. 7, ll. 47-59.) In Murakami’s words, “before a liquid material for
deposition is actually flowed and fed, residual liquid material in the
evaporator 8, etc. can be expelled.” (Id. at ll. 47-50.) Moreover, Murakami
teaches that “[t]he pre-expelling operation need not be conducted
immediately before a deposition, but may be conducted immediately after a
preceding deposition is over.” (Id. at ll. 56-58.) According to Murakami,
“[o]ccurrence of overshoots of a liquid material supply amount can be
precluded in deposition, whereby the deposition material can be fed stably
and accurately,” resulting in higher quality films. (Id. at col. 10, ll. 45-50.)

13 Dead space 50 is shown in Figure 2, but not reproduced here.
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Murakami provides additional discharge passages 54B and 54C to
remove of low vapor pressure liquid from the transfer lines via inert gas
pressure and solvent washes when reservoir 4 needs to be changed.
(Murakami at col. 5, ll. 26-40 and at col. 7, l. 50 to col. 9, l. 21.) Murakami
explains the advantages of these features as follows:
liquid material in the passages can be substantially perfectly
expelled without contact of the liquid material with air for
maintenance of the respective members and replacement of
the reservoir. Accordingly production of byproducts by
oxidation of the liquid material, and clogging of the passages
with the byproducts can be precluded. Liquid material supply
can be stable.
(Id. at col. 10, ll. 52-58; emphasis added.)
C. Discussion
As the Appellant, Lindfors bears the procedural burden of showing
harmful error in the Examiner’s rejections. See, e.g., Shinseki v. Sanders,
129 S. Ct. 1696, 1706 (2009) (“the burden of showing that an error is
harmful normally falls upon the party attacking the agency’s
determination.”).
Initially, we note that Lindfors has expressly waived argument in this
appeal regarding the fitness of Bondestram as prior art in the rejection under
§ 103. Although Lindfors reserves the option of removing Bondestram by
swearing behind or “asserting common co-ownership under
35 U.S.C. § 103(c),” Lindfors states that “we do not need to remove
Bondestram at this time in view of the arguments in the body of the appeal
brief.” (Br. 12 n.1.) Thus, Lindfors concedes that Bondestram is, on the
present record, properly applied as a reference under § 103. We note further
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that Lindstrom has not advanced any substantive arguments regarding the
teachings of Bondestram or the propriety of combining those teachings with
the teachings of Murakami or Modisette, save that Bondestram does not cure
the alleged defects of those references. (Id. at 12, 14.) Thus, Lindfors has
also waived substantive argument regarding Bondestram. Finally, with
regard to each of the obviousness rejections relying in part Kaloyeros (id.
at 14), Sturm (id. at 15), van Buskirk (id.), or Gauthier (id. at 16), Lindfors
states that “[t]he Appellant neither admits nor denies these allegations by the
Examiner.” (Br. 14, 15, and 16.) Rather, Lindfors merely asserts that the
additional references do not remedy the deficiencies of the rejection of
independent claim 12. Thus, Lindfors has also waived all substantive
arguments regarding the additional references. Accordingly, all claims stand
or fall with claim 12.
Lindfors’ principal argument, that Murakami “teaches away from
returning reactants to the liquid reservoir” (Br. 12, second full para.), is
without merit. The Federal Circuit has explained that “[a] reference may be
said to teach away when a person of ordinary skill, upon reading the
reference . . . would be led in a direction divergent from the path that was
taken by the applicant.” In re Gurley, 27 F.3d 551, 553 (Fed. Cir. 1994).
There is no indication in Murakami that contact of the highly reactive low
vapor pressure liquid with oxygen is a problem in the “pre-expelling” step of
removing the residual low vapor pressure liquid from the evaporator. It is
clear from the disclosure that the evaporator and the transfer lines attached
to it are maintained in an oxygen-free state during use. The passages that
Lindfors cites relate to the desirability of preventing contact of the low vapor
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pressure liquid with oxygen during exchange of an empty reservoir 4 for a
full reservoir. The purpose of the helium-driven liquid expelling operations
and the purge liquid operations described in columns 8-9 is precisely to
insure maintenance of oxygen-free conditions in the apparatus during such
an exchange. Thus, Murakami cannot be said to teach away from recycling
the unevaporated low vapor pressure liquid in the absence of oxygen.
The critical differences, according to the Examiner, between the
teachings of Murakami and the claimed process are the inert gas valving
steps (which are associated with Atomic Layer Deposition processes), for
which the Examiner relies on Bondestram, and the recycling of the low
vapor pressure liquid, for which the Examiner relies on Modisette for
evidence supporting motivation. As already noted, Lindfors has not argued
error in the Examiner’s reliance on Bondestram.
Lindfors’ criticisms of the Examiner’s reliance on Modisette are not
well taken. We understand the Examiner to have relied on Modisette as
evidence that recycling materials is a well known procedure in chemical
processing. Modisette’s illustration of the recovery of a solvent, and return
of the solvent to the reservoir from whence it came, stands as evidence that a
person having ordinary skill in the chemical arts would have been motivated
to recycle a reagent, such as the unevaporated liquid collected by Murakami,
in order to conserve materials. Such a person would have taken precautions
to avoid known degradative conditions, such as exposure to oxygen, as a
matter of routine. Thus, the Examiner’s reliance on Modisette was not
harmful, as a chemist of ordinary skill would have adopted the general
teaching of recycling, but not the specific conditions described by Modisette.
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Similarly, Lindfors has not shown harmful error in the Examiner’s
suggestion (FR 5, Ans. 5) that the valve VB and nozzle 20 could be used to
return the low vapor pressure liquid to reservoir 4. Lindfors has not directed
our attention to any credible evidence that the skilled reactor designer would
not have been able to add components or to adopt existing components to
perform the obvious recycling step.
We therefore AFFIRM the Examiner’s rejections.
D. Order
We AFFIRM the rejection of claims 12-14, 19-23, 26, and 30 under
35 U.S.C. § 103(a) in view of the combined teachings of Murakami,
Modisette, and Bondestram.
We AFFIRM the rejection of claims 15 and 16 under
35 U.S.C. § 103(a) in view of the combined teachings of Murakami,
Modisette, Bondestram, and Kaloyeros.14
We AFFIRM the rejection of claims 17, 31, and 32 under
35 U.S.C. § 103(a) in view of the combined teachings of Murakami,
Modisette, Bondestram, Kaloyeros, and Sturm.15
We AFFIRM the rejection of claims 24 and 25 under
35 U.S.C. § 103(a) in view of the combined teachings of Murakami,
Modisette, Bondestram, and Van Buskirk.16

14 Alain E. Kaloyeros et al., U.S. Patent 5,476,409 (1994).
15 Edward A. Sturm et al., U.S. Patent 6,178,925 B1 (2001).
16 Peter C. Van Buskirk et al., U.S. Patent 5,882,416 (1999).
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We AFFIRM the rejection of claims 33 and 34 under
35 U.S.C. § 103(a) in view of the combined teachings of Murakami,
Modisette, Bondestram, and Gauthier.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1).

AFFIRMED

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