DETAILED ACTION
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.
Claim(s) 1-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Weidman et al. (US 2006/0246217) in view of Ozaki (US 2007/0163617) and Kumar et al. (WO 2006/091510).
Regarding Claims 1-2, 5-6, 11, and 15-16, Weidman et al. (US’217) teach a method of exposing a substrate surface having at least one feature thereon to a preclean process, the at least one feature defining a via having a top surface, a bottom surface, and two opposed sidewalls (Figs. 1A-2F; [0005-0007,0032-0034]), the preclean process comprising exposing the top surface, the bottom surface, and the two opposed sidewalls to a precleaning process for removing a metal oxide (e.g. molybdenum, ruthenium, or tungsten oxide) from a substrate surface [0012, 0013,0034,0053], the method comprising: exposing the substrate surface to a cleaning plasma, comprising hydrogen to form a clean metal surface (e.g. tungsten, ruthenium, silicon) [0034,0038,0053,0060].
US’217 fails to teach a cleaning plasma comprising hydrogen (H2) and oxygen (O2) in a range of from 1 % to 20% oxygen (O2) to remove metal oxide. Ozaki (US’617) teach an analogous method for cleaning oxides (e.g. tungsten oxide) off of a surface (chamber wall) with a cleaning plasma (Abstract), the cleaning plasma comprising hydrogen (H2) and oxygen (O2) in a range including 11 %and 20% oxygen (O2) (e.g. H2 is four times O2, or 80:20,[0018, 0079]; H2 is six times O2, or 86:14 [0079]; H2 is eight times O2, or 89:11 [0018]) to improve cleaning [0074,0079]. It would have been obvious to a person of ordinary skill in the art at the time of invention to modify the process of US’217 with the composition of cleaning plasma within the recited range, because US’617 suggests a plasma comprising a mixture of H2 and O2 within the recited range to clean surfaces containing a metal oxide, including those like tungsten oxide. Although US’617 fails to expressly teach chemical reactions occurring between the mixture of H1 and O-2 plasma at the suggested concentrations (ratio of H1 and O-2 plasma of 4 or more, most preferably 8 for sublimating tungsten oxide), the chemical reactions occurring between the claimed oxides and the plasma at the suggested concentrations would be expected to be the same both in the claims and in US’617. Moreover, the excess H-2 (by 4x to 8x) would be expected to reduce the metal oxide to metal to at least some extent during sublimation.
The combination of US’217 in view of US’617 fails to teach an unbiased plasma. Kumar et al. (WO’510) is analogous art, pertinent to the problem of providing a plasma to treat a substrate, and suggests that an unbiased plasma permits treatment of an entire or substantially all surfaces of a trench and vias, including sides and bottom, including removing metal oxides (p. 16, last paragraph through p. 17, second paragraph). It would have been obvious to a person of ordinary skill in the art at the time of invention to modify the process of the combination of US’217 in view of US’617 with an unbiased plasma, because WO’510 suggests that an unbiased plasma permits improved cleaning of an entire or substantially all surfaces of a trench and vias, including sides and bottom, including the removal of metal oxides.
Regarding Claims 3 and 13, US’617 teaches H2 is eight times O2, or 89:11 [0018]), which is obviously close to the claimed range of 90% H2. In addition, US’617 provides evidence that choosing a specific ratio of H2 O2 is a matter of routine optimization (Fig. 8; [0045]); thus, the recited range of 90:10 is obvious as a result of routine optimization. Also, generally, differences in concentration will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration is critical.
Regarding Claims 4 and 14, US’217 teaches that a surface is free or substantially free of oxide such as by cleaning it with plasma [0034-0035].
Regarding Claims 7 and 17, US’217 [0036] teaches an inductively coupled plasma, and US’617 teaches an inductively coupled plasma [0017].
Regarding Claims 8 and 18, US’217 teaches a temperature of 20-150 C [0035,0042]. US’217 fails to teach a temperature of 300 to 750 C. US’617 teaches a cleaning temperature of about 600 C [0018] or 400 C [0093]. Also, WO’510 suggests a substrate temperature of 200-400 C (p. 17, third paragraph). Additionally, US’617 provides evidence that cleaning temperature is an optimizable variable [0100], since chamber temperature was varied to test the effect of temperature on the concentration of tungsten (Fig. 10; [0100]). Thus, it would have been obvious to a person of ordinary skill in the art at the time of invention to modify the process of the combination of references by heating the substrate to a temperature to within the recited range through routine optimization. Also, generally, differences in concentration will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration is critical, and the claims do not require any specific substrate.
Regarding Claims 9 and 19, US’217 teaches a pressure of 100 mTorr (0.1 Torr) to about 450 Torr [0035,0038]. US’617 suggests 502 mTorr (67 Pa) [0018], including 50 mTorr or greater [0071]. It would have been obvious to a person of ordinary skill in the art at the time of invention to modify the process of the combination of references with a pressure within the recited range, because the combination of references suggests a plasma at the recited pressure, including one with the recited composition. Moreover, because temperature and pressure are state variables that determine the state of plasma, it would have been obvious to a person of ordinary skill in the art at the time of invention to modify the process of the combination of references with a pressure within the recited range to obtain a plasma.
Regarding Claim 10 and 20, US’217 teaches depositing a metal film after precleaning [0005,0007,0010].
Regarding Claim 12, US’217 teaches an aspect ratio of 10:1 or greater [0005].
Response to Arguments
Applicant's arguments filed 1 May 2026 have been fully considered but they are not persuasive.
In response to Applicant’s argument Ozaki (US ‘617) merely states that H2 can cause WOx to be more easily sublimated because WOx is deoxidized into a more unstable state [0077] such as ions and therefore does not constitute a complete reduction to metallic tungsten W, but rather still in an oxidized form (Remarks, p. 7), the argument is not convincing, because US’617 exposes tungsten oxide at a ratio of H2/O2 of 4 to 8, equivalent to 11% to 20% O2, which is within the claimed concentration for the same material; therefore, even though US’617 does not speculate on specific reaction mechanisms, the identity or obvious similarity between the claimed and taught oxides and the preferred concentrations of O-2 to H2 in US’617 within the recited ranges suggests the identical or obviously similar reactions. That Applicant may recognize a reaction occurring in the process taught in US’617 that US’617 does not recognize does not make the process patentable. Applicant has not provided sufficient reason to think that the preferred concentration of H2 and O2 in plasmas acting on WOx in US’617 would not react in the same way with WOx within the same range of concentration. Moreover, as Applicant acknowledges, US’617 specifically says that WOx is deoxidized, even though Applicant has argued that this still means tungsten in an oxidized form without providing support for the claim that this still means that tungsten, deoxidized, is still in an oxidized form. Also, the excess of H2 in O2 of 4x to 8x would have been expected to result in at least some reduction of WOx to provide metal gas during sublimation.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Ozaki et al. (US 7,887,637) (cleaning WOx from surface with a mixture of H2 and O2 at concentrations greater than 2 times, preferably 4 or more, most preferably 8 or more)
No claim is allowed.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALEXANDER M WEDDLE whose telephone number is (571)270-5346. The examiner can normally be reached 9:30-6:30.
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ALEXANDER M WEDDLE
Examiner
Art Unit 1712
/ALEXANDER M WEDDLE/Primary Examiner, Art Unit 1712
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