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 § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 3-8 and 10-17 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claim 3, line 3, the phrase "in which the acid catalyst is a stronger acid than the acetic acid" renders the claim indefinite because it is unclear when the hydrogen, acetic acid being used as “acid catalyst”, how this acid catalysts could be stronger acid than acetic acid?
Regarding claim 4, lines 5-6, the phrase “ in order to increase the etch selectivity of the silicon germanium to the material, the proportion of the etching inhibitor is decreased”? because, in lines 3-4, increasing etch selectivity of SiGe to the material, the proportion of the etching inhibitor is increased, such limitation is contradictory.
Claim 6 recites the limitation "the first removal operation" in line 4. There is insufficient antecedent basis for this limitation in the claim.
Claims 7 and 8 depends on the claim 6 and therefore, also include the limitation.
Claim 10 recites the limitation "the pull etching operation" in the last line of claim 10. There is insufficient antecedent basis for this limitation in the claim.
Claim 12 recites the limitation "the etching inhibitor" in the lines 1-2. There is insufficient antecedent basis for this limitation in the claim.
Claims 11-17 directly or indirectly depends on the claim 10 and therefore, also include the limitation.
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.
Claim(s) 1-5, 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Liu et al (US 2024/0271040) in view of Woo et al (US 12,630,764).
Regarding claim 1, Liu et al disclose a process of selectively removing/etching of silicon-germanium over silicon with good compatibility to SiO.sub.2 from a microelectronic device that includes: [0011] (i) water; [0012] (ii) at least one oxidizer; [0013] (iii) at least one fluoride ion source; [0014] (iv) at least one polyfunctional acid; [0015] (v) at least one corrosion inhibiting surfactant; [0016] (vi) at least one silane silicon oxide etch inhibitor; and [0017] (vii) optionally at least one water-miscible organic solvent [0010], [0036]; the oxidizing agent comprises hydrogen peroxide ([0062]; and claim 47).
Liu et al disclose that the fluoride ion source includes hydrofluoric acid [0064] reads on the claimed “etchant” and the at least one silane silicon oxide etch inhibitor reads on the claimed “etching inhibitor”.
Liu et al also disclose that the etching solutions employ an effective silicon oxide corrosion inhibitor, therefore the SiGe etch rate can be increased at higher HF concentration, and the silicon and silicon oxide etch rates are not affected [0134].
Unlike the instant invention, Liu et al fail to teach the etch rate and/or the etch selectivity for the silicon germanium is controlled by adjusting a proportion of at least one of the etching chemicals and the etching inhibitor used in the preparation of the etchant.
However, one of ordinary skill in the art would have been easily recognize that a proportion of the etching chemicals including the silicon oxide etch inhibitor be controlled by adjusting the components used during the etching as taught by Liu et al [0134].
Additionally, in the same field of endeavor, Woo et al disclose that if the content of the fluorine-based compound is excessively low in less than 0.1% by weight based on 100% by weight of the total composition, the etching rate is too slow to meet general process conditions. If the content of the fluorine-based compound is excessively high in excess of 20% by weight based on 100% by weight of the total composition, the etching rate is too fast and an etching variation in the substrate increases (col.5, lines 50-60).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to employ Woo et al's teaching of increasing or decreasing the etchant content in an etching solution can affect the etching rate into the teaching of Liu et al because increasing or decreasing the etchant content in an etching solution can affect the etching rate as taught by Woo et al.
Regarding claim 2, Liu et al also disclose that the etching solutions employ an effective silicon oxide corrosion inhibitor, therefore the SiGe etch rate can be increased at higher HF concentration, and the silicon and silicon oxide etch rates are not affected [0134].So, one of ordinary skill in the art would decrease the etching chemical or lower the HF concentration to decrease the etch rate of SiGe layer.
Regarding claim 3, Liu et al disclose that etching solution comprises water; (ii) at least one oxidizer; [0013] (iii) at least one fluoride ion source; [0014] (iv) at least one polyfunctional acid; [0015] (v) at least one corrosion inhibiting surfactant; [0011]-[0016] and the oxidizing agent includes hydrogen peroxide [0061],[0062].
Regarding claim 4-5, Liu et al disclose that the etching solution of the disclosed and claimed subject matter exhibit (i) high selectivity of the etch for silicon-germanium over silicon and (ii) high selectivity of the etch for silicon-germanium over silicon oxide [0108]; wherein the silicon and the silicon oxide reads on the claimed “material”; and aforesaid teaching easily motivated to one of ordinary skill in the art in order to increase the etching selectivity of SiGe to other material (silicon or silicon oxide), the proportion of the etching inhibitor is increased.
Regarding claim 6, modified Liu et al may not disclose the selective etching or removal of SiGe from silicon material in two-step processes, namely a first removal operation and a second removal operation, wherein the proportion of the etching chemical is adjusted to be a first proportion and a second proportion, respectively; and the second proportion is lower than the first proportion; and for the claim 7, the proportion of the etching inhibitor is adjusted to be a “A proportion” and a second proportion “B proportion”, respectively; and the “B proportion” is higher than the “A proportion”.
However, in the modified teach above appears to teach that etching solutions employ an effective silicon oxide corrosion inhibitor, therefore the SiGe etch rate can be increased at higher HF concentration, and the silicon and silicon oxide etch rates are not affected (see Liu et al [0134]). Woo et al disclose above that if the content of the fluorine-based compound is excessively low in less than 0.1% by weight based on 100% by weight of the total composition, the etching rate is too slow to meet general process conditions. If the content of the fluorine-based compound is excessively high in excess of 20% by weight based on 100% by weight of the total composition, the etching rate is too fast and an etching variation in the substrate increases (col.5, lines 50-60).
Therefore, one of ordinary skill in the art easily motivated to optimize the content of the etching chemical and etching inhibitor for desired selectivity and additionally, in general, the transposition of process steps or the splitting of one step into two, where the processes are substantially identical or equivalent in terms of function, manner and result, was held to be not patentably distinguish the processes. Ex parte Rubin 128 USPQ 440 (PTO BdPatApp 1959).
Regarding claim 9, from the above modified teaching, one of ordinary skill in the art would have been easily recognized that to keep the content or the proportion of the etching chemicals during the selective etching of SiGe, the flow rate of the chemicals would have been adjusted to maintain the desired selectivity as taught by Liu et al in view of Woo et al.
Claim(s) 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Liu et al (US 2024/0271040) in view of Woo et al (US 12,630,764) as applied to claims 1 and 6 above, and further in view of LOPEZ VILLANUEVA et al; herein in after, Lopez et al (US 2024/0282584).
Modified Liu et al disclose above for the claims 1 and 6 but fail to teach a pre-etching step.
However, in the same field of endeavor, Lopez et al disclose a composition and process of selective etching of silicon/SiGe, wherein etching is performed with etch batch preparation along with pre-etching [0187]-[0189].
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to employ Lopez et al's teaching of pre-etching step into the teaching of modified Liu et al for effectively initiating the etching process.
Claim(s) 10-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Liu et al (US 2024/0271040) in view Chao et al (US 2022/0406920).
Regarding claims 10-11 and 16-17, Liu et al disclose a process of selectively removing/etching of silicon-germanium over silicon with good compatibility to SiO.sub.2 from a microelectronic device that includes: [0011]; Li et al focusing semiconductor device manufacturing, wherein the device having GAA structure [0003], an epi-stack can be formed of alternating silicon (Si) and silicon germanium (SiGe) layers, wherein the SiGe layers are the sacrificial layers and the Si layers are the channel layers. The SiGe layers can then be removed by selective etching (for example via a wet etching process such as a hydrogen peroxide containing solution) [0005].
Unlike the instant invention, Liu et al fail to teach the etching is performed in sequentially two step process, namely a indent etching to remove only a portion of the first layer (SiGe) and a full etching operation to remove the reminder of the first layer, wherein the etchant proportion is different from each other.
However, in the same field of endeavor, Chao et al disclose a method for fabricating a non-planar transistor device, which includes a sequential combination of at least a first etching process and a second etching process to pattern the cladding layer, wherein the cladding layer also containing SiGe [0011]; aforesaid teaching easily reads on the limitation of indent etching to remove a portion of the first layer and full etching the reminder of the first layer.
Chao et al may not disclose the proportion of the first etching and the second etching process is different but one of ordinary skill in the art would have been obviously optimize the proportion of the etchant, such as the proportion should be higher at the initial etching process than the final or the second etching process in order to remove the reminder or rest of the layer to be etched.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to employ Chao et al's teaching of sequential etching operations into the teaching of Liu et al for effective removal of the first layer (SiGe) as suggested by Chao et al.
Regarding claim 12, Liu et al disclose that the fluoride ion source includes hydrofluoric acid [0064] reads on the claimed “etchant” and the at least one silane silicon oxide etch inhibitor reads on the claimed “etching inhibitor”; and without showing any criticality of such proportion, the content or proportion could be optimized by one of ordinary skill in the art for predictable result or desired etching or removal rate.
Regarding claims 13-15, without showing any criticality of such proportion of the etchant and etching inhibitor and temperature of the etchant would have been optimized for predictable results because such are result-effective variables.
In general, the selection of reaction parameters such as temperature and concentration would have been obvious: More particularly, where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller 105 USPQ 233, 255 (CCPA 1955).See also In re Waite 77 USPQ 586 (CCPA 1948); In re Scherl 70 USPQ 204 (CCPA 1946).
Conclusion
The prior art made of record, listed in the PTO892 and not relied upon is considered pertinent to applicant's disclosure. Park et al (US 2025/0157825) discoes an etching process using an etching composition comprises fluorine-containing acid and a catalyst, can enhance SiGe removal, selectively. It is also believed that the catalyst can significantly inhibit the removal of certain dielectric materials (e.g., SiOx) in the semiconductor substrate during the etching process [0021], [0028].
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SHAMIM AHMED whose telephone number is (571)272-1457. The examiner can normally be reached M-TH (8-5:30pm).
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Joshua Allen can be reached at 571-270-3176. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format.
For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
SHAMIM AHMED
Primary Examiner
Art Unit 1713
/SHAMIM AHMED/ Primary Examiner, Art Unit 1713
Prosecution Insights