CTFR 17/908,177 CTFR 87601 DETAILED ACTION This is the Office action based on the 17908177 application filed August 30, 2022, and in response to applicant’s argument/remark filed on March 20, 2026. Claims 1-6 are currently pending and have been considered below. Notice of Pre-AIA or AIA Status 07-03-aia AIA 15-10-aia The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA. 07-06 AIA 15-10-15 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 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. Claim Rejections - 35 USC § 103 07-20-aia AIA 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 of this title, 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. 07-23-aia AIA The factual inquiries set forth in Graham v. John Deere Co. , 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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. Claims 1-6 rejected under 35 U.S.C. 103 as obvious over Lin et al. (U.S. PGPub. No. 20220293594), hereinafter “Lin’594”, in view of Lebby et al. (U.S. Pat. No. 5034092), hereinafter “Lebby”. --Claims 1, 5, 6: Lin’594 teaches a method of fabricating a Gate All Around stacked transistor ([0011]), comprising providing a substrate 302 comprising silicon germanium ([0018], Fig. 3B), then patterning the substrate 302 to form fins 402 and 404 ([0020], Fig. 4B);forming dummy fins 602 and 604 over the substrate 302, the dummy fins comprise hafnium oxide ([0033], Fig. 6B);forming a gate structure layer 702 over the fins and dummy fins ([0038-0043], Fig. 7B);forming a photoresist mask 902 that cover a dummy fin 602 ([0021, 0049-0051], Fig. 9A);performing a first etching the gate structure layer 702 to expose the dummy fin 604 ([0059]), then performing a second etching to completely remove the dummy fin while fins 402 and 404 remain intact ([0059], Fig. 12B), wherein second etching may comprise a plasma of a mixture of an etch gas and a passivation gas, wherein the etch gas may comprise chlorine, hydrogen bromide, carbon tetrafluoride, fluoroform, difluoromethane, fluoromethane, hexafluoro-1,3-butadiene, boron trichloride, sulfur hexafluoride, hydrogen, nitrogen trifluoride, and the passivation gas may comprise nitrogen (N 2 ), oxygen (O 2 ), carbon dioxide (CO 2 ), sulfur dioxide (SO 2 ), carbon monoxide (CO), methane (CH 4 ), silicon tetrachloride (SiCl 4 )” ([0070]). It is noted that Fig. 11B and 12B shows that the dummy fin layer 604-1 is completely etched away while the layer 404 remains intact. Therefore, the hafnium oxide dummy fin 604-1 is selectively etched with respect to the silicon germanium layer 404. Lin’594 further teaches to use boron trichloride as the etch gas when etching a dummy fin comprising hafnium oxide ([0071]), and that the etch gas and/or the passivation gas may be diluted with a gas such as Ar, He, Ne or other suitable dilutive gas ([0070]). Lin’594 fails to teach the claimed feature that the second etch uses a mixed gas of BCl 3 and SiCl 4 , and wherein the flow rate of the SiCl 4 is smaller than a flow rate of the BCl 3 gas. Lebby, also directed to plasma etching a semiconductor substrate, teaches that the etching may be advantageously performed by using a plasma comprising silicon tetrachloride and boron trichloride to provide an etching that has less etch damage, a greater degree of anisotropy and a more controlled etch (abstract). Lebby further teaches that “(s)ilicon tetrachloride gas is injected into the plasma reactor so that a range between 20 percent and 90 percent by volume is maintained” and “(b)oron trichloride gas is also injected into the plasma reactor so that a range between 10 percent and 90 percent by volume is maintained” (Col. 3, Lines 24-33). It is noted that this is equivalent to a ratio SiCl4:BCl3 of 25% to 900%, and a ratio of SiCl 4 :total gas flow of 20 vol .% to 90 vol.% Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention to select SiCl 4 from the list of the passivation gases to be used with the BCl 3 gas in the invention of Lin’594 because Lebby teaches that this would provide an etching that has less etch damage, a greater degree of anisotropy and a more controlled etch. It would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to select a ratio SiCl 4 :BCl 3 of 25% or a ratio of SiCl 4 :total gas flow of 20 vol .% because Lin’594 is silent about the gas flow amount and Lebby teaches that such gas flows would be effective. It is noted this reads on the gas ratio recited in claims 1 and 5--Claim 2: Since the dummy fin is etched completely from the substrate, it would have been obvious, in routine experimentations, that it is etched from all directions, one of which is perpendicular to the direction that the layer 404 is formed.--Claims 3, 4: Since Lin’594 teaches that the SiCl 4 is a passivation gas and the etching is selective to the dummy fin layer 604-1, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention to flow the passivation gas and the etch gas such as the passivation layer formed by the passivation gas is thicker on the other layers and thinner on the dummy fin layer 604-1 since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. In re Aller, 105 USPQ 233. Claims 1-6 rejected under 35 U.S.C. 103 as obvious over Peng et al. (U.S. PGPub. No. 20220302257), hereinafter “Peng”, in view of Liu et al. (U.S. PGPub. No. 20090004870), hereinafter “Liu” and Lebby: --Claims 1, 5, 6: Peng teaches a method of fabricating a FinFET transistor in an Gate All Around structure ([0014]), comprising forming a stack of SiGe layers 102a alternate with Si layers 102b (Fig. 1, [0018]);forming a dummy gate dielectric layer 618 on the stack, the dummy gate dielectric layer 618 may be made of HfO 2 (Fig. 6, [0033-0034]);removing a top Si layer 102b to expose a SiGe layer 102a on the stack (Fig. 15-16, [0050]);selectively etching the dummy gate dielectric layer 618 along the sidewall of the stack (Fig. 17-18, [0051-0052]). Fig. 17-18 show that the hafnium layer 618 is completely removed while the SiGe layer 102a remains intact; therefore, the hafnium oxide layer 618 is selectively etched with respect to the silicon germanium layer 102a. Peng is silent about a method for the selectively etching. Liu, also directed to a method of etching a hafnium oxide layer 304 ([0031, 0040]) in the presence of a silicon-containing layer 306 ([0057]) by using BCl 3 ([0052-0053], Fig. 4B-C)) during fabricating a semiconductor device, teaches that a silicon and halogen containing gas, such as SiCl 4 , may be used to passivate and protect the sidewall of the silicon-containing layer ([0050]) Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to select SiCl 4 from the list of the passivation gas in the invention of Lin’594 because Liu teaches that this would advantageously passivate and protect the sidewall of the other silicon-containing layers that are exposed to the etching. Peng and Liu fail to teach the claimed feature a flow rate of SiCl 4 is smaller than a flow rate of the BCl 3 gas. Lebby, also directed to plasma etching a semiconductor substrate, teaches that the etching may be advantageously performed by using a plasma comprising silicon tetrachloride and boron trichloride to provide an etching that has less etch damage, a greater degree of anisotropy and a more controlled etch (abstract). Lebby further teaches that “(s)ilicon tetrachloride gas is injected into the plasma reactor so that a range between 20 percent and 90 percent by volume is maintained” and “(b)oron trichloride gas is also injected into the plasma reactor so that a range between 10 percent and 90 percent by volume is maintained” (Col. 3, Lines 24-33). It is noted that this is equivalent to a ratio SiCl 4 :BCl 3 of 25% to 900%, and a ratio of SiCl 4 :total gas flow of 20 vol .% to 90 vol.% Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention to select SiCl 4 from the list of the passivation gases to be used with the BCl 3 gas in the invention of Lin’594 because Lebby teaches that this would provide an etching that has less etch damage, a greater degree of anisotropy and a more controlled etch. It would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to select a ratio SiCl 4 :BCl 3 of 25% or a ratio of SiCl 4 :total gas flow of 20 vol .% because Lin’594 is silent about the gas flow amount and Lebby teaches that such gas flows would be effective. It is noted this reads on the gas ratio recited in claims 1 and 5--Claim 2: it is noted that the dummy gate dielectric layer 618 is etched from the lateral direction, which is perpendicular to the vertical direction that the layer 102a is formed.--Claims 3, 4: Since Liu teaches that the SiCl 4 is a passivation gas and the etching is selective to the dummy gate dielectric layer 618, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention to flow the passivation gas and the etch gas such as the passivation layer formed by the passivation gas is thicker on the other layers and thinner on the dummy gate dielectric layer 618 since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. In re Aller, 105 USPQ 233. Response to Arguments Applicant's arguments filed March 20, 2026 have been fully considered as follows:--Regarding Applicant’s argument that the previously cited prior arts do not teach all features of claim 1 or 6 because Lin’594 and Peng do not teach all of the features, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Furthermore, see In re McLaughlin, 443 F.2d 1392, 1395 (CCPA 1971) (“[T]he test for combining references is not what the individual references themselves suggest but rather what the combination of disclosures taken as a whole would suggest to one of ordinary skill in the art.”). Appellant’s arguments also fail to adequately consider the skill and creativity of the ordinary artisan. See KSR, 550 U.S. at 421 (“A person of ordinary skill is also a person of ordinary creativity, not an automaton.”). In this case in the first ground of rejection Lin’594 modified by Lebby teaches all features of claims 1-6. In the second ground of rejection Peng modified by Liu and Lebby teaches all features of claims 1-6.--Regarding Applicant’s argument that Lebby fails to disclose HfO 2 and SiGe films, these films are disclosed by Lin’594 and Peng. Specifically, a) Lin’594 teaches to perform a second etching to completely remove the dummy fin while fins 402 and 404 remain intact ([0059], Fig. 12B), wherein second etching may comprise a plasma of a mixture of an etch gas and a passivation gas, wherein the etch gas may comprise chlorine, hydrogen bromide, carbon tetrafluoride, fluoroform, difluoromethane, fluoromethane, hexafluoro-1,3-butadiene, boron trichloride , sulfur hexafluoride, hydrogen, nitrogen trifluoride, and the passivation gas may comprise nitrogen (N 2 ), oxygen (O 2 ), carbon dioxide (CO 2 ), sulfur dioxide (SO 2 ), carbon monoxide (CO), methane (CH 4 ), silicon tetrachloride (SiCl 4 ) ” ([0070]). It is noted that Fig. 11B and 12B shows that the dummy fin layer 604-1 is completely etched away while the layer 404 remains intact. Therefore, the hafnium oxide dummy fin 604-1 is selectively etched with respect to the silicon germanium layer 404 . Lin’594 further teaches to use boron trichloride as the etch gas when etching a dummy fin comprising hafnium oxide ([0071]), and that the etch gas and/or the passivation gas may be diluted with a gas such as Ar, He, Ne or other suitable dilutive gas ([0070]). Lin’594 fails to teach the claimed feature that the second etch uses a mixed gas of BCl 3 and SiCl 4 , and wherein the flow rate of the SiCl 4 is smaller than a flow rate of the BCl 3 gas. Lebby, also directed to plasma etching a semiconductor substrate, teaches that the etching may be advantageously performed by using a plasma comprising silicon tetrachloride and boron trichloride to provide an etching that has less etch damage, a greater degree of anisotropy and a more controlled etch (abstract). Lebby further teaches that “(s)ilicon tetrachloride gas is injected into the plasma reactor so that a range between 20 percent and 90 percent by volume is maintained” and “(b)oron trichloride gas is also injected into the plasma reactor so that a range between 10 percent and 90 percent by volume is maintained” (Col. 3, Lines 24-33). It is noted that this is equivalent to a ratio SiCl4:BCl3 of 25% to 900%, and a ratio of SiCl 4 :total gas flow of 20 vol.% to 90 vol.% Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention to select SiCl 4 from the list of the passivation gases to be used with the BCl 3 gas in the invention of Lin’594 because Lebby teaches that this would provide an etching that has less etch damage, a greater degree of anisotropy and a more controlled etch.b) Peng teaches etching a hafnium layer 618 with respect to a SiGe layer 102a but is silent about a method for the selectively etching. Liu, also directed to a method of etching a hafnium oxide layer 304 ([0031, 0040]) in the presence of a silicon-containing layer 306 ([0057]) by using BCl 3 ([0052-0053], Fig. 4B-C)) during fabricating a semiconductor device, teaches that a silicon and halogen containing gas, such as SiCl 4 , may be used to passivate and protect the sidewall of the silicon-containing layer ([0050]) Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to select SiCl 4 from the list of the passivation gas in the invention of Lin’594 because Liu teaches that this would advantageously passivate and protect the sidewall of the other silicon-containing layers that are exposed to the etching. Peng and Liu fail to teach the claimed feature a flow rate of SiCl 4 is smaller than a flow rate of the BCl 3 gas. Lebby, also directed to plasma etching a semiconductor substrate, teaches that the etching may be advantageously performed by using a plasma comprising silicon tetrachloride and boron trichloride to provide an etching that has less etch damage, a greater degree of anisotropy and a more controlled etch (abstract). Lebby further teaches that “(s)ilicon tetrachloride gas is injected into the plasma reactor so that a range between 20 percent and 90 percent by volume is maintained” and “(b)oron trichloride gas is also injected into the plasma reactor so that a range between 10 percent and 90 percent by volume is maintained” (Col. 3, Lines 24-33). It is noted that this is equivalent to a ratio SiCl 4 :BCl 3 of 25% to 900%, and a ratio of SiCl 4 :total gas flow of 20 vol .% to 90 vol.% Therefore, it would have been obvious to one of ordinary skill in the art at the effective filing date of the invention to select SiCl 4 from the list of the passivation gases to be used with the BCl 3 gas in the invention of Lin’594 because Lebby teaches that this would provide an etching that has less etch damage, a greater degree of anisotropy and a more controlled etch. It would have been obvious to one of ordinary skill in the art at the effective filing date of the invention, in routine experimentations, to select a ratio SiCl 4 :BCl 3 of 25% or a ratio of SiCl 4 :total gas flow of 20 vol .% because Lin’594 is silent about the gas flow amount and Lebby teaches that such gas flows would be effective. It is noted this reads on the gas ratio recited in claims 1 and 5.--Regarding Applicant’s argument that Lebby teaches “the preferred ratio of the SiCl 4 gas to the BCl ₃ gas is equal, to wit: "Silicon tetrachloride (SiCl 4 ) and boron trichloride (BCl ₃ ) gases are used to generate a plasma that etches exposed surfaces on substrate 10. Silicon tetrachloride gas is injected into the plasma reactor so that a range between 20 percent and 90 percent by volume is maintained. It is referred however that a 50 percent by volume of silicon tetrachloride gas be maintained. Boron trichloride gas is also injected into the plasma reactor so that a range between 10 percent and 90 percent by volume is maintained. It is preferred however that a 50 percent by volume of boron trichloride gas be maintained.", which implies Lebby teaches against setting the flow rate ratio of SiCl 4 in a range from 3 to 20% as in Applicant’s claimed method, this argument is not persuasive. See In re Lemelson, 397 F.2d 1006, 1009 (CCPA 1968) (“The use of patents as references is not limited to what the patentees describe as their own inventions or to the problems with which they are concerned. They are part of the literature of the art, relevant for all they contain.”) Moreover, a reference is not limited to its preferred embodiment, but must be evaluated for all of its teachings, including its teachings of non-preferred embodiments. See In re Burckel, 592 F.2d 1175, 1179 (CCPA 1979). In this instance, that a single example/embodiment describes ranges that fall outside the claimed ranges is not sufficient to overcome the prima facie case of obviousness set forth by the Examiner. Conclusion 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 extension fee 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 THOMAS PHAM whose telephone number is (571) 270-7670 and fax number is (571) 270-8670. The examiner can normally be reached on MTWThF9to6 PST. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Joshua Allen can be reached on (571) 270-3176. 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If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /THOMAS T PHAM/Primary Examiner, Art Unit 1713 Application/Control Number: 17/908,177 Page 2 Art Unit: 1713 Application/Control Number: 17/908,177 Page 3 Art Unit: 1713 Application/Control Number: 17/908,177 Page 4 Art Unit: 1713 Application/Control Number: 17/908,177 Page 5 Art Unit: 1713 Application/Control Number: 17/908,177 Page 6 Art Unit: 1713 Application/Control Number: 17/908,177 Page 7 Art Unit: 1713 Application/Control Number: 17/908,177 Page 8 Art Unit: 1713 Application/Control Number: 17/908,177 Page 9 Art Unit: 1713
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