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.
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 1-11 and 13-20 are rejected under 35 U.S.C. 103 as being unpatentable over Gordon et al (WO 2025/006215 A1).
Gordon discloses a semiconductor processing method [0049] comprising:
providing a fluorine-containing precursor (thermal etchant gas, e.g., F2 [0049]) and a secondary precursor (“radical generating gas” e.g., ozone O3, [0049]) to a processing region 202 (“lower chamber region” [0065], Fig. 1B) of a semiconductor processing chamber 201 (Fig. 1B), wherein the secondary precursor comprises a carbon-containing precursor (e.g., carbon monoxide, [0051]), a hydrogen-containing precursor (e.g., hypochlorous acid, hydrogen peroxide, hypobromous acid [0051]), a nitrogen-containing precursor (e.g., nitric acid, nitric oxide, nitrogen dioxide, nitrous oxide, [0051]), or an oxygen-containing precursor (e.g., ozone, nitrogen dioxide or nitric oxide [0049], dioxygen [0051]), wherein a substrate 226 is housed within the processing region [0069], and wherein a silicon-containing material and a silicon-and-germanium-containing material are disposed on the substrate [0080];
contacting the substrate with the fluorine-containing precursor and the secondary precursor [0079]; and
selectively removing at least a portion of the silicon-and-germanium-containing material from the substrate [0080].
Gordon discloses that the substrate temperature is kept at -40 to 500 °C [0081]. The upper range of this range, from 200° to 500°C, overlaps with the cited range. The temperature in the processing region above the substrate is expected to be similar to the temperature of the substrate. Further, Gordon teaches that “moving to higher temperatures can create more tunable selectivity where SiGe materials are etched close to 1:1 but remain highly selective to Si" [0087]. It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to provide the cited processing region temperature range in the method of Gordon because Gordon teaches similar temperatures are useful for processing, and because Gordon teaches that increasing the temperature provides for tunable selectivity, which can be used to optimize the process for best results.
As to claim 2, Gordon discloses that the fluorine-containing precursor may comprise nitrogen trifluoride (NF3) [0050].
As to claim 3, Gordon discloses that an additional secondary gas is methane (CH4) [0052].
As to claim 4, Gordon discloses that an additional secondary gas may comprise ammonia (NH3) [0052].
As to claim 5, Gordon fails to disclose the flow rate ratio. However, Gordon teaches that the ratio of the thermal etchant gas (equivalent to the instant invention’s “fluorine-containing precursor”) to the radical generating gas (equivalent to the instant invention’s “secondary precursor” or “chemical additive”) changes the nature of the etching from a radical regime to a molecular regime (see Fig. 4), which in turn relates to how the selectivity changes [0084]. Accordingly, it would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to provide the cited flow rate ratio in the method of Gordon because Gordon teaches that ratios of gases in general are important and useful for optimizing the process for desired etch selectivity.
As to claim 6, Gordon discloses that an additional secondary gas may comprise ammonia (NH3) [0052].
As to claim 7, Gordon discloses that the secondary gas is the oxygen-containing precursor; and the oxygen containing precursor comprises diatomic oxygen (O2) [0051].
As to claim 8, Gordon discloses that the processing region is maintained plasma-free (“thermal molecular etching (without plasma)” [0005]; “thermal etchant (without plasma)” [0047]; Fig. 3 “Thermal Radical” as opposed to “Plasma Radical” processing).
As to claim 9, Gordon discloses a pressure range of 100 mT to 10 Torr, or 200 mT to 7 Torr [0081], which overlaps with the cited range.
As to claim 10, Gordon discloses an etch rate of the silicon-and-germanium-containing material is greater than or about 0.5 Å/minute (Fig. 9).
As to claim 11, see the rejection of claim 1. Further, Gordon discloses providing an oxygen-containing precursor and a hydrogen containing precursor (H2O2 or HOCl) [0051].
As to claim 13, Gordon discloses to include diatomic oxygen (O2) [0051], which may be combined with a further secondary gas of a hydrogen-containing precursor such as NH3, H2, CH4, CH3F CH2F2, H2O, HF [0052]. It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to provide the cited combination of O2 and a hydrogen containing precursor in the method of Gordon because Gordon teaches that they are useful gases for SiGe etching and such is expected to give a predictable result of etching SiGe.
As to claim 14, Gordon teaches that an additional secondary gas includes diatomic hydrogen (H2) [0052].
As to claim 15, see the rejection of claim 8.
As to claim 16, see the rejection of claim 1. Gordon discloses a temperature range of up to 500 °C, which overlaps with the cited range from 400° to 500°C. It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to maintain the processing region at a temperature of greater than or about 400 °C in the method of Gordon because Gordon teaches similar temperatures are useful for processing, and because Gordon teaches that increasing the temperature provides for tunable selectivity, which can be used to optimize the process for best results.
As to claim 17, Gordon discloses a pressure range of 100 mT to 10 Torr, or 200 mT to 7 Torr [0081], which overlaps with the cited range.
As to claim 18, see the rejection of claims 1 and 8.
As to claim 19, Gordon discloses that the halogen-containing precursor comprises nitrogen trifluoride (NF3) [0050].
As to claim 20, Gordon discloses that the substrate temperature is kept at -40 to 500 °C [0081]. The upper range of this range, from 350° to 500°C, overlaps with the cited range. The temperature in the processing region above the substrate is expected to be similar to the temperature of the substrate. Further, Gordon teaches that “moving to higher temperatures can create more tunable selectivity where SiGe materials are etched close to 1:1 but remain highly selective to Si" [0087]. It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to provide the cited processing region temperature range in the method of Gordon because Gordon teaches similar temperatures are useful for processing, and because Gordon teaches that increasing the temperature provides for tunable selectivity, which can be used to optimize the process for best results.
Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Gordon et al (WO 2025/006215 A1), as applied to claim 11, and further in view of Cui et al (US 11,062,921 B1).
As to claim 12, Gordon discloses a fluorine-containing precursor such as NF3, but fails to disclose tungsten hexafluoride (WF6).
Cui teaches that a precursor similar to nitrogen trifluoride includes tungsten hexafluoride (col.12, lines 5-15) is useful for etching because of ease of dissociation at increased temperature (col.12, lines 18-19). It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to use tungsten hexafluoride for the fluorine-containing precursor in the method of Gordon because Cui teaches that it is a useful alternative for nitrogen trifluoride in etching methods and such is expected to be useful because of its ease of dissociation at increased temperatures, which is desired in the thermal process of Gordon.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Karolik et al (US 9,236,265 B2) is cited to show SiGe etching with a fluorine-containing precursor.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANITA K ALANKO whose telephone number is (571)270-0297. The examiner can normally be reached Monday-Friday, 9 am-5pm.
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/ANITA K ALANKO/Primary Examiner, Art Unit 1713
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