Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 3, and 5 are rejected under 35 U.S.C. 103 as being unpatentable over Shinriki et al. (US 2004/0251235 A1) in view of O’Hara (US 2014/0017901 A1), and further in view of Lubomirsky et al. (US 2018/0358244 A1).
Regarding claim 1, Shinriki teaches an etching method for etching a silicon oxide film (native oxide formed on the surface of silicon substrate W is removed using hydrogen fluoride generated in processing vessel 11B; paragraphs [0002]-[0007], [0065]-[0068], and [0091]).
Shinriki teaches using a processing gas containing hydrogen fluoride and water vapor (hydrogen radicals H* and fluorine radicals F* generate hydrogen fluoride HF*, and water vapor is simultaneously provided as a catalyst during removal of the native oxide film; paragraphs [0065]-[0072], [0097]-[0098], and [0106]).
Shinriki continues to teach supplying a precursor gas of the processing gas to a chamber in which a substrate having the silicon oxide film on a surface thereof is disposed (substrate W having native oxide on its surface is retained on mount 12 within processing vessel 11B, and precursor gases are supplied into processing vessel 11B; paragraphs [0077]-[0086] and [0091]).
Shinriki further teaches supplying water vapor to the chamber (water vapor is supplied through water-vapor line 14m to processing vessel 11 during removal of the native oxide film; paragraphs [0096]-[0098]).
Shinriki teaches etching the silicon oxide film using the processing gas in the chamber to which the water vapor is supplied (native oxide on substrate W is removed in processing vessel 11B using generated hydrogen fluoride while water vapor is supplied to the processing vessel; paragraphs [0065]-[0072], [0091], [0097]-[0098], and [0106]).
Shinriki further teaches that supplying the precursor gas to the chamber includes supplying a first precursor gas containing a hydrogen radical to the chamber from a first gas supply line (hydrogen gas supplied through hydrogen line 14d is excited in remote plasma source 13 to generate hydrogen radicals H*, which are introduced into processing vessel 11B; paragraphs [0079], [0084], and [0089]).
Shinriki teaches supplying a second precursor gas containing a gas containing fluorine to the chamber from a second gas supply line (fluorine gas diluted with argon is separately supplied through fluorine line 14i, mass-flow controller 14L, and processing-gas port 14 into processing vessel 11B; paragraphs [0080], [0085], and [0090]).
Shinriki further teaches producing the hydrogen fluoride by reaction of the first precursor gas and the second precursor gas with each other in the chamber (hydrogen radicals H* and fluorine radicals F* react in processing vessel 11B to generate hydrogen fluoride HF*, which removes the native oxide film; paragraphs [0065]-[0068] and [0086]).
Shinriki does not expressly teach that the processing gas further contains ammonia.
O’Hara teaches that the processing gas further contains ammonia (ammonia is employed as a hydrogen-compound gas during hydrogen fluoride vapor etching and provides increased etch selectivity; paragraphs [0013] and [0056]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Shinriki to include ammonia in the processing gas because O’Hara teaches that ammonia has been employed as a hydrogen-compound additive during hydrogen fluoride vapor etching to provide increased etch selectivity (paragraph [0056]), and use of a known technique to improve similar methods in the same way is obvious, see MPEP § 2141 III(C).
Modified Shinriki does not expressly teach supplying the water vapor to the whole of a surface of the substrate in the chamber.
Lubomirsky teaches supplying the water vapor to the whole of a surface of the substrate in the chamber (water-vapor source 693 supplies water vapor through the plurality of apertures 683 extending across shower plate 625 above substrate 302, thereby directing the water vapor across the substrate surface; paragraphs [0055] and [0062]; Figures 6B and 8B).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the modified method of Shinriki to supply the water vapor through apertures extending across a shower plate above the substrate because Lubomirsky teaches supplying water vapor through a plurality of apertures 683 extending across shower plate 625 above substrate 302 (paragraphs [0055] and [0062]; Figures 6B and 8B), and combining prior art elements according to known methods to yield predictable results is obvious, see MPEP § 2141 III(A).
Regarding claim 3, modified Shinriki teach the limitations of claim 1 above.
Lubomirsky teaches wherein the chamber includes a processing chamber in which the substrate is disposed (substrate 302 is disposed on chuck 650 within first chamber region 684; paragraphs [0054]-[0055]; Figures 6B and 8B).
Lubomirsky further teaches the chamber includes a gas supply chamber connected to the first gas supply line and the second gas supply line (NF₃ source 691 and NH₃ source 692 are connected through gas inlet 676 to second chamber region 681; paragraphs [0054]-[0055]; Figures 6B and 8B).
Lubomirsky also teaches a shower plate that includes a plurality of through holes and is disposed between the gas supply chamber and the processing chamber (first showerhead 625 including apertures 682 is disposed between second chamber region 681 and first chamber region 684; paragraphs [0055] and [0062]; Figures 6B and 8B).
Lubomirsky further teaches the processing gas is supplied to the substrate in the processing chamber from the gas supply chamber through the shower plate (reactive process gas supplied to second chamber region 681 passes through apertures 682 of first showerhead 625 into first chamber region 684 toward substrate 302; paragraphs [0055] and [0062]; Figures 6B and 8B).
Regarding claim 5, Lubomirsky teach the limitations of claim 3 above. Lubomirsky further teaches wherein the water vapor is supplied to the processing chamber (water vapor source 693 supplies water vapor through apertures 683 toward first chamber region 684, where substrate 302 is disposed; paragraph [0062]; Figures 8A and 8B).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Shinriki et al. in view of O’Hara and Lubomirsky et al., as applied to claim 3 above, and further in view of Chebi et al. (US 2012/0064686 A1).
Regarding claim 4, modified Shinriki teaches the limitations of claim 3 above.
Modified Shinriki does not expressly teach wherein the water vapor is supplied to the gas supply chamber.
Chebi teaches wherein the water vapor is supplied to the gas supply chamber (water vapor is supplied through gas lines 130 into the chamber above showerhead 124, corresponding to the gas supply chamber; paragraphs [0065]-[0066]; Figures 9-11B).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the modified method of Shinriki to supply the water vapor to the gas supply chamber because Chebi teaches supplying water vapor above the showerhead into the gas supply chamber to provide different control over the solvation zone, the reaction of the plasma and water, and the formation of clusters (paragraphs [0065]-[0066]), and use of a known technique to improve similar methods in the same way is obvious, see MPEP § 2141 III(C).
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Shinriki et al. in view of O’Hara and Lubomirsky et al., as applied to claim 1 above, and further in view of Park et al. (US 2014/0080309 A1).
Regarding claim 2, Shinriki, O’Hara, and Lubomirsky teach the limitations of claim 1 above.
Modified Shinriki does not expressly teach controlling the water vapor to have a partial pressure of 0.1 Pa or more and 100 Pa or less.
Park teaches etching silicon oxide using water vapor and a fluorine-containing precursor, wherein the combined flow rates of the water vapor and the fluorine-containing precursor account for about 0.05 volume percent to about 20 volume percent of the overall gas mixture (paragraph [0043]), and the substrate processing region has a pressure of about 500 mTorr to about 30 Torr, including about 5 Torr to about 15 Torr (paragraph [0045]). Park further teaches that the fluorine-containing precursor and the water vapor are each flowed at about 25 sccm to about 200 sccm (paragraph [0042]).
Using the ideal gas law and Dalton’s law of partial pressure the partial pressure
(
P
i
)
of a gas is determined according to
P
i
=
V
i
V
t
o
t
a
l
P
t
o
t
a
l
where
V
i
represents the volumetric flow of the gas,
V
t
o
t
a
l
represents the total volumetric flow, and
P
t
o
t
a
l
represents the total chamber pressure.
Park’s disclosed combined volume fraction of 0.05 percent to 20 percent corresponds to
V
i
V
t
o
t
a
l
values of 0.0005 to 0.2.
For
V
i
V
t
o
t
a
l
=
0.005
and
P
t
o
t
a
l
ranging from 500 mTorr to 30 Torr,
P
i
ranges from 0.25 mTorr, approximately 0.033 Pa, to 0.015 Torr, approximately 2 Pa. For
V
i
V
t
o
t
a
l
=
0.2
and
P
t
o
t
a
l
ranging from 500 mTorr to 30 Torr,
P
i
ranges from 100 mTorr, approximately 13 Pa, to 6 Torr, approximately 800 Pa. Thus, the combined partial pressure of the water vapor and fluorine-containing precursor ranges from approximately 0.033 Pa to 800 Pa.
Using Park’s narrower total-pressure range of 5 Torr to 15 Torr results in a combined partial-pressure range of approximately 0.33 Pa to 400 Pa. Park further teaches identical volumetric flow-rate ranges of about 25 sccm to about 200 sccm for the fluorine-containing precursor and the water vapor (paragraph [0042]). Selecting equal flow rates within these disclosed ranges results in each gas representing approximately one-half of the combined gas fraction. The calculated water-vapor partial-pressure range is therefore approximately 0.017 Pa to 400 Pa using Park’s broader total-pressure range, or approximately 0.17 Pa to 200 Pa using Park’s narrower total-pressure range. Each calculated range overlaps the claimed water-vapor partial-pressure range of 0.1 Pa to 100 Pa.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of modified Shinriki to supply the water vapor at a partial pressure of 0.1 Pa to 100 Pa because Park teaches supplying water vapor during silicon oxide etching under operating conditions that result in water-vapor partial pressures overlapping the claimed range, and where the claimed range overlaps or lies within a range disclosed by the prior art, a prima facie case of obviousness exists. See MPEP § 2144.05.
Conclusion
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/JONATHAN L CARTER/Examiner, Art Unit 1713
/ERIN F BERGNER/Primary Examiner, Art Unit 1713
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