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 .
Status of Claims
Claims 1 and 3-6 are amended in view of applicant’s response filed 3/20/2026. Claim 2 is canceled. Claims 11-20 remain withdrawn from consideration. Therefore, claims 1 and 3-10 are currently under examination.
Claim Rejections - 35 USC § 103
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.
Claim(s) 1and 3-10 is/are rejected under 35 U.S.C. 103 as being unpatentable over “Study of Thin SiO2 and its Interface Formed by Thermal Oxidation of RF Hydrogen Plasma-Cleaned Silicon”, Szekeres et al. Vacuum, Vol. 61, Iss. 2-4, May 14th, 2004, pg 263-268(Szekeres), and further in view of Shinriki et al. US 2004/0251235 A1(Shinriki), and further in view of Lee et al. US 2020/0135900A1(Lee).
Szekeres teaches a process for forming a SiO2 film on the surface of a silicon wafer, comprising cleaning the surface of the Si wafer with RF hydrogen plasma to remove native oxide prior to thermally oxidizing the cleaned Si wafer to form a thin SiO2 film (Abstract and Introduction).
Regarding claim 1, the Si wafer of Szekeres is exposed to hydrogen plasma (implying generation of hydrogen radicals) in a reactor, wherein the Si wafer is kept at 300°C and 133Pa(i.e. 1Torr) for 15min, followed by thermally oxidizing the clean Si wafer in dry oxygen at 850°C and at atmospheric pressure (i.e. 760Torr)(pg 264, 1st and 2nd paragraphs under Experimental details).
However, Szekeres does not explicitly teach that the hydrogen plasma used in the cleaning step is generated by remote plasma.
Shinriki teaches a dry cleaning process for removing native oxide on the surface of a Si substrate(abstract, [0005]), wherein the Si substrate in a processing vessel is exposed to hydrogen radicals generated by remote plasma (Fig. 3A-3B, [0014-0023,0086]).
Therefore, it would have been obvious to one of ordinary skill in the art to have incorporated the remote hydrogen plasma cleaning as taught by Shinriki into the hydrogen plasma cleaning of Szekeres in order to efficiently remove native oxide in a shorter time as taught by Shinriki[0094].
However, Szekeres in view of Shinriki do not explicitly teach the claimed removal of hydrogen ions from an effluent of a remote plasma source.
Lee teaches performing plasma cleaning on a surface of a silicon substrate (abstract), wherein the plasma cleaning can be done by using a remote plasma generator[0050]. Lee further teaches a filter is applied at the effluent of the plasma generation chamber to filter hydrogen ions, which is generated by the plasma generator along with hydrogen radicals[0052].
Therefore, it would have been obvious to one of ordinary skill in the art to have incorporated the hydrogen ion filter as taught by Lee into the process of Szekeres in view of Shinriki in order to remove the hydrogen ions generated by the remote plasma since Lee teaches that hydrogen ions impinging on silicon can cause damage or defect and reducing the hydrogen ions improves results from plasma cleaning[0052].
Regarding claim 3, Fig. 1 of Shinriki further teaches that the cleaning process takes about 1.5minutes[0072], which reads on the claimed duration of 1sec to 5 min.
Regarding claim 4, Shinriki further teaches that the Si substrate is maintained at 300°C during the cleaning process[0088], which reads on the claimed 25-700°C.
Regarding claim 5, Shinriki teaches that hydrogen gas and argon gas are supplied to the remote plasma source to produce hydrogen radicals(Fig. 4A and 4B, [0089]), wherein hydrogen gas is provided at a flow of 100 SCCM and Ar gas is provided at a flow of 500-1000 SCCM[0089]. Therefore, the amount of hydrogen gas in the combined flow of argon and hydrogen reads on the claimed 1-100% total hydrogen in the gas flow as claimed.
Regarding claim 6, Shinriki further teaches that the pressure of the processing vessel is set at 13.3Pa – 4kPa (i.e. 0.1-300Torr) when hydrogen radicals are introduced to the processing vessel[0089], which encompasses the claimed pressure of 0.01Torr to 20Torr. Therefore, a prima facie case of obviousness exists. See MPEP 2144.05.
Regarding claim 7, Szekeres further teaches that oxygen flow was changed to nitrogen and the samples were pulled out(page 264, 2nd paragraph under Experimental Details). Szekeres’ teaching implies that the thermal oxidation step takes 20mins, which reads on the claimed oxidation duration of 1sec to 20 mins.
Regarding claim 8, the thermal oxidation temperature of Szekeres 850°C reads on the claimed oxidation temperature of 25-1200°C.
Regarding claim 9, since Szekeres teaches that dry oxygen with <3ppm water content is used in the thermal oxidation step(2nd paragraph under Experimental details), the examiner concludes that the concentration of the oxygen supplied in the thermal oxidation step of Szekeres is ≥97% which reads on the claimed 1-100%.
Regarding claim 10, Szekeres further teaches that the thermal oxidation takes place at atmospheric pressure(i.e. 760 Torr), which reads on the claimed 0.1-800Torr.
Response to Arguments
Applicant’s arguments in the response filed 3/20/026 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to LOIS L ZHENG whose telephone number is (571)272-1248. The examiner can normally be reached Mon-Fri 8:15-4:45.
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LOIS ZHENG
Primary Examiner
Art Unit 1733
/LOIS L ZHENG/Primary Examiner, Art Unit 1733
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