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 .
Drawings
The drawings are objected to as failing to comply with 37 CFR 1.84(p)(5) because they include the following reference character(s) not mentioned in the description: 151 in Figure 2. Corrected drawing sheets in compliance with 37 CFR 1.121(d), or amendment to the specification to add the reference character(s) in the description in compliance with 37 CFR 1.121(b) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
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.
Claim 6 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 pre-AIA the applicant regards as the invention.
Claim 6 recites the limitation "the halogen-containing precursor". There is insufficient antecedent basis for this limitation in the claim, and therefore the claim is indefinite.
Claim 6 is only dependent upon claim 1, however the term “halogen-containing precursor” was properly introduced within claim 5. For the purpose of compact prosecution, claim 6 will be examined as if it were dependent upon claim 5.
Claim Rejections - 35 USC § 102
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.
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale or otherwise available to the public before the effective filing date of the claimed invention.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1-4, 7-8, and 12 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Lee et al. (US-20230116213-A1).
Regarding Claim 1 Lee teaches a semiconductor processing method (Paragraphs [0015-0018] methods related to semiconductor device fabrication) comprising:
providing a boron-and-halogen-containing precursor and an oxygen-containing precursor to a processing region of a semiconductor processing chamber (Paragraph [0047] the absorber layer can be etched with a gas that includes BCl3 and O2. Paragraph [0058] the etching process can be a RIE etching process), wherein a substrate is housed in the processing region, wherein a layer of metal-containing hardmask material is disposed on the substrate, and wherein a layer of silicon-containing material is disposed on the layer of metal-containing hardmask material (Paragraphs [0041-0046] the absorber layer (element 140) can comprise a transition metal as the main alloy element within it. Paragraph [0048] Figure 3E a hard mask layer (element 160) is disposed over the absorber layer and can be silicon oxide. Paragraph [0061] Figure 3I the absorber layer is used as a mask in later processes step to etch the second capping layer (element 130));
forming plasma effluents of the boron-and-halogen-containing precursor and the oxygen-containing precursor (Paragraph [0047] the absorber layer can be etched with a gas that includes BCl3 and O2. Paragraph [0058] the etching process can be a RIE etching process); and
contacting the substrate with the plasma effluents of the boron-and-halogen-containing precursor and the oxygen-containing precursor, wherein the contacting etches a feature in the layer of metal-containing hardmask material (Paragraph [0047] the absorber layer can be etched with a gas that includes BCl3 and O2. Paragraph [0058] the etching process can be a RIE etching process), and wherein the contacting forms a layer of passivation material on sidewalls of the feature in the layer of metal-containing hardmask material (Lee is silent on the formation of a passivation material on sidewalls. However, given that the method based on the disclosure in Lee, as outlined above, is substantially similar to that in instant claims, it is the examiner's position that the formation of a passivation material on the sidewalls would have inherently occurred as part of the method as instantly claimed. Since PTO cannot conduct experiments the proof of burden is shifted to the applicants to establish a nonobviousness difference. See MPEP 2112. When the structure recited in the reference is substantially identical to that of the claims, claimed properties or functions are presumed to be inherent. The Courts have held that it is well settled that where there is a reason to believe that a functional characteristic would be inherent in the prior art, the burden of proof then shifts to the applicant to provide objective evidence to the contrary. See MPEP 2112.01(I)).
Regarding Claim 2, Lee teaches wherein the boron-and-halogen-containing precursor comprises boron trichloride (BCl3) (Paragraph [0047] BCl3 can be used in the dry etch).
Regarding Claim 3, Lee teaches wherein the oxygen-containing precursor comprises diatomic oxygen (O2) (Paragraph [0047] O2 can be used in the dry etch).
Regarding Claim 4, Lee teaches wherein the layer of metal-containing hardmask material comprises tungsten (Paragraphs [0041-0046] the absorber layer (element 140) can comprise a transition metal as the main alloy element within it).
Regarding Claim 7, Lee teaches wherein the layer of metal-containing hardmask material is characterized by a metal content of greater than or about 40 at.% (Paragraph [0045] the main alloy in the absorber comprises more than 50 atomic percent of the alloy).
Regarding Claim 8, Lee teaches wherein the layer of silicon-containing material comprises silicon oxide (Paragraph [0048] Figure 3E a hard mask layer (element 160) is disposed over the absorber layer and can be silicon oxide).
Regarding Claim 12, Lee teaches wherein the boron-and-halogen-containing precursor and the oxygen-containing precursor are silicon-free (Paragraph [0047] the absorber layer can be etched with a gas that includes BCl3 and O2, which do not contain silicon).
Claims 13-14 and 16-20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Yoon et al. (US-20160314981-A1).
Regarding Claim 13, Yoon teaches a semiconductor processing method (Paragraph [0002] methods of forming patterns for semiconductors) comprising:
i) providing a boron-and-halogen-containing precursor to a processing region of a semiconductor processing chamber (Paragraph [0052] Figure 1B an etch gas, that can be BCl3, which is boron-and-halogen-containing, is used in a plasma etch process to etch the metal-containing layer. Paragraph [0091] process gas is supplied to the plasma limitation area), wherein a substrate is housed in the processing region, wherein a layer of metal-containing hardmask material is disposed on the substrate, and wherein a layer of silicon-containing material is disposed on the layer of metal-containing hardmask material (Paragraphs [0049-0050] Figure 1A substrate is provided that comprises a metal layer (element 12) with a mask layer (element 13) over the metal layer, where the mask layer can be silicon oxide or silicon nitride. Paragraphs [0087-0091] process can be conducted within apparatus shown in Figure 6A, where the substrate (element 90) is provided to the region including plasma limitation area (element 1111) for the operations, where the precursors are supplied to the plasma limitation area for the operations);
ii) forming plasma effluents of the boron-and-halogen-containing precursor (Paragraph [0052] Figure 1B an etch gas, that can be BCl3, which is boron-and-halogen-containing, is used in a plasma etch process to etch the metal-containing layer. Paragraph [0096] plasma is generated and used to treat the substrate);
iii) contacting the substrate with the plasma effluents of the boron-and-halogen-containing precursor, wherein the contacting etches a feature in the layer of metal-containing hardmask material (Paragraph [0052] Figure 1B an etch gas, that can be BCl3, which is boron-and-halogen-containing, is used in a plasma etch process to etch the metal-containing layer. Paragraph [0096] plasma is generated and used to treat the substrate);
iv) providing an oxygen-containing precursor to the processing region of the semiconductor processing chamber (Paragraph [0056] Figure 1C oxygen (O2) is used in a plasma process to form a passivation layer (element 15a) over exposed portions of the metal-containing layer. Paragraphs [0087-0091] process can be conducted within apparatus shown in Figure 6A, where the substrate (element 90) is provided to the region including plasma limitation area (element 1111) for the operations, where the precursors are supplied to the plasma limitation area for the operations); and
v) contacting the substrate with the oxygen-containing precursor, wherein the contacting oxidizes a portion of sidewalls of the feature in the layer of metal-containing hardmask material (Paragraph [0056] Figure 1C oxygen (O2) is used in a plasma process to form a passivation layer (element 15a) over exposed portions of the metal-containing layer).
Regarding Claim 14, Yoon teaches that the method further comprises: providing one or more halogen-containing precursors to the processing region of the semiconductor processing chamber with the boron-and-halogen-containing precursor (Paragraph [0052] the etch gas can a mixed gas of the chlorine-containing gas and a fluorine-containing gas).
Regarding Claim 16, Yoon teaches wherein operations i) through v) are repeated for a second cycle (Paragraphs [0057-0059] the etch process step and passivation step are repeated as showing in Figures 1D and 1F. Paragraph [0062] process can be a cyclic process).
Regarding Claim 17, Yoon teaches wherein repeating operation iii) in the second cycle forms a layer of passivation material on the sidewalls of the feature in the layer of metal-containing hardmask material (Paragraph [0059] Figure 1F a second passivation layer (element 15b) is formed on sidewalls of metal layer (element 12)).
Regarding Claim 18, Yoon teaches a semiconductor processing method (Paragraph [0002] methods of forming patterns for semiconductors) comprising:
providing a boron-and-halogen-containing precursor to a processing region of a semiconductor processing chamber (Paragraph [0052] Figure 1B an etch gas, that can be BCl3, which is boron-and-halogen-containing, is used in a plasma etch process to etch the metal-containing layer. Paragraph [0091] process gas is supplied to the plasma limitation area), wherein a substrate is housed in the processing region, wherein a layer of metal-containing hardmask material is disposed on the substrate, and wherein a patterned layer of silicon-containing material is disposed on the layer of metal-containing hardmask material (Paragraphs [0049-0050] Figure 1A substrate is provided that comprises a metal layer (element 12) with a mask layer (element 13) over the metal layer, where the mask layer can be silicon oxide or silicon nitride. The mask layer is patterned to have an opening (element 17). Paragraphs [0087-0091] process can be conducted within apparatus shown in Figure 6A, where the substrate (element 90) is provided to the region including plasma limitation area (element 1111) for the operations, where the precursors are supplied to the plasma limitation area for the operations);
forming plasma effluents of the boron-and-halogen-containing precursor (Paragraph [0052] Figure 1B an etch gas, that can be BCl3, which is boron-and-halogen-containing, is used in a plasma etch process to etch the metal-containing layer. Paragraph [0096] plasma is generated and used to treat the substrate);
contacting the substrate with the plasma effluents of the boron-and-halogen-containing precursor, wherein the contacting etches a first portion of a feature in the layer of metal-containing hardmask material (Paragraph [0052] Figure 1B an etch gas, that can be BCl3, which is boron-and-halogen-containing, is used in a plasma etch process to etch the metal-containing layer. Paragraph [0096] plasma is generated and used to treat the substrate),
providing an oxygen-containing precursor to the processing region of the semiconductor processing chamber (Paragraph [0056] Figure 1C oxygen (O2) is used in a plasma process to form a passivation layer (element 15a), that can comprise oxidizing a tungsten layer, over exposed portions of the metal-containing layer. Paragraphs [0087-0091] process can be conducted within apparatus shown in Figure 6A, where the substrate (element 90) is provided to the region including plasma limitation area (element 1111) for the operations, where the precursors are supplied to the plasma limitation area for the operations);
contacting the substrate with the oxygen-containing precursor, wherein the contacting oxidizes sidewalls of the feature in the layer of metal-containing hardmask material (Paragraph [0056] Figure 1C oxygen (O2) is used in a plasma process to form a passivation layer (element 15a), that can comprise oxidizing a tungsten layer, over exposed portions of the metal-containing layer);
providing the boron-and-halogen-containing precursor to the processing region of the semiconductor processing chamber (Paragraph [0057] Figure 1D an etch gas, that can be BCl3, which is boron-and-halogen-containing, is used in a plasma etch process to etch the metal-containing layer and forms a polymer layer (element 16) on sidewalls of the feature. Paragraphs [0087-0091] process can be conducted within apparatus shown in Figure 6A, where the substrate (element 90) is provided to the region including plasma limitation area (element 1111) for the operations, where the precursors are supplied to the plasma limitation area for the operations);
forming plasma effluents of the boron-and-halogen-containing precursor (Paragraph [0057] Figure 1D an etch gas, that can be BCl3, which is boron-and-halogen-containing, is used in a plasma etch process to etch the metal-containing layer and forms a polymer layer (element 16) on sidewalls of the feature. Paragraph [0096] plasma is generated and used to treat the substrate); and
contacting the substrate with the plasma effluents of the boron-and-halogen-containing precursor, wherein the contacting etches a second portion of the feature in the layer of metal-containing hardmask material, and wherein the contacting forms a layer of passivation material on sidewalls of the feature in the layer of metal-containing hardmask material (Paragraph [0057] Figure 1D an etch gas, that can be BCl3, which is boron-and-halogen-containing, is used in a plasma etch process to etch the metal-containing layer and forms a polymer layer (element 16) on sidewalls of the feature. Paragraph [0096] plasma is generated and used to treat the substrate).
Regarding Claim 19, Yoon teaches wherein the boron-and-halogen-containing precursor comprises boron trichloride (BCl3) (Paragraphs [0052] and [0057] BCl3 can be used in the etch gas).
Regarding Claim 20, Yoon teaches that the method further comprises: forming plasma effluents of the oxygen-containing precursor (Paragraph [0056] Figure 1C oxygen (O2) is used in a plasma process to form a passivation layer (element 15a), that can comprise oxidizing a tungsten layer, over exposed portions of the metal-containing layer. Paragraph [0096] plasma is generated and used to treat the substrate).
Claim Rejections - 35 USC § 103
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.
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 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 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Lee in view of Ni et al. (US-6465159-B1).
Regarding Claim 1, (Note: Claim 1 was rejected above under an interpretation that the formation of a passivation material on sidewalls of the feature would be an inherent result of the etching method taught by Lee. An alternative rejection is formulated here for claim 1 where that claimed limitation is not interpreted as inherent) Lee teaches a semiconductor processing method (Paragraphs [0015-0018] methods related to semiconductor device fabrication) comprising:
providing a boron-and-halogen-containing precursor and an oxygen-containing precursor to a processing region of a semiconductor processing chamber (Paragraph [0047] the absorber layer can be etched with a gas that includes BCl3 and O2. Paragraph [0058] the etching process can be a RIE etching process), wherein a substrate is housed in the processing region, wherein a layer of metal-containing hardmask material is disposed on the substrate, and wherein a layer of silicon-containing material is disposed on the layer of metal-containing hardmask material (Paragraphs [0041-0046] the absorber layer (element 140) can comprise a transition metal as the main alloy element within it. Paragraph [0048] Figure 3E a hard mask layer (element 160) is disposed over the absorber layer and can be silicon oxide. Paragraph [0061] Figure 3I the absorber layer is used as a mask in later processes step to etch the second capping layer (element 130));
forming plasma effluents of the boron-and-halogen-containing precursor and the oxygen-containing precursor (Paragraph [0047] the absorber layer can be etched with a gas that includes BCl3 and O2. Paragraph [0058] the etching process can be a RIE etching process); and
contacting the substrate with the plasma effluents of the boron-and-halogen-containing precursor and the oxygen-containing precursor, wherein the contacting etches a feature in the layer of metal-containing hardmask material (Paragraph [0047] the absorber layer can be etched with a gas that includes BCl3 and O2. Paragraph [0058] the etching process can be a RIE etching process).
Lee fails to teach that the contacting forms a layer of passivation material on sidewalls of the feature in the layer of metal-containing hardmask material.
Ni teaches methods related to semiconductor processing and etching (Column 1 lines 5-7). Ni teaches a method of etching that utilizes an oxidizing gas, that comprises oxygen, and a passivation gas, where the passivation gas can be a boron containing gas, that react to form a passivation film on sidewalls during etching (Column 2 lines 26-46). Ni teaches that the boron containing gas can be BCl3 (Column 4 lines 14-17). Ni teaches that the passivation film formed can be B2O2 (Column 4 lines 18-28).
It would have been obvious to one of ordinary skill in the art to have modified the method of Lee by including within the etching process the formation of a passivation film made of byproducts of the etching gases on the sidewalls of the feature being etched, as taught by Ni.
This modification would have been obvious to one of ordinary skill in the art because it can be considered the combination of prior art elements according to known methods to yield predictable results. Lee teaches an etching process and Ni teaches that a similar etching process, utilizing similar etching gases, that a passivation film layer is formed on the sidewalls of the etched feature. This combination would have had the predictable result of forming a passivation layer on sidewalls during the etching process. See MPEP 2143(I)(A).
Regarding Claim 9, Lee teaches all the limitations of claim 1 as outlined above.
Lee fails to teach that the layer of passivation material comprises a boron-and-oxygen-containing material.
Ni teaches methods related to semiconductor processing and etching (Column 1 lines 5-7). Ni teaches a method of etching that utilizes an oxidizing gas, that comprises oxygen, and a passivation gas, where the passivation gas can be a boron containing gas, that react to form a passivation film on sidewalls during etching (Column 2 lines 26-46). Ni teaches that the boron containing gas can be BCl3 (Column 4 lines 14-17). Ni teaches that the passivation film formed can be B2O2 (Column 4 lines 18-28).
It would have been obvious to one of ordinary skill in the art to have modified the method of Lee such that the passivation material that formed on the sidewalls of the feature during the etching process comprised B2O2, as taught by Ni.
This modification would have been obvious to one of ordinary skill in the art because it can be considered the combination of prior art elements according to known methods to yield predictable results. This combination would have had the predictable result of forming a passivation layer on sidewalls during the etching process that comprised B2O2. See MPEP 2143(I)(A).
Claims 5-6 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Lee, as applied to claim 1 above, and further in view of Yoon.
Regarding Claims 5 and 6, Lee teaches all the limitations of claim 1 as outlined above.
Lee fails to teach that a halogen-containing precursor is provided to the processing region with the boron-and-halogen-containing precursor, as required by claim 5, or that the halogen-containing precursor comprises diatomic chlorine (Cl2), hydrogen bromide (HBr), or both, as required by claim 6.
Yoon teaches methods of forming patterns for semiconductors (Paragraph [0001]). Yoon teaches a method of etching where an etch gas, that can comprise BCl3, is supplied for a plasma etching process to etch a metal-containing layer (Paragraph [0052]). Yoon teaches that the etch gas can further comprise additional gases, for example a fluorine containing gas or an additional chlorine containing gas such as Cl2 (Paragraph [0052]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Lee by including an additional gas with the boron-and-halogen-containing precursor, as taught by Yoon.
This modification would have been obvious as it could be considered the combination of prior art elements according to known methods to yield predictable results. This combination would have had the predictable result of supplying a gas suitable for use in a plasma etching process to etch and metal containing layer. See MPEP 2143(I)(A).
Regarding Claim 11, Lee teaches all the limitations of claim 1 as outlined above.
Lee fails to teach wherein the semiconductor processing chamber operating temperature is greater than or about 20 °C.
Yoon teaches methods of forming patterns for semiconductors (Paragraph [0001]). Yoon teaches a method of etching where an etch gas, that can comprise BCl3, is supplied for a plasma etching process to etch a metal-containing layer (Paragraph [0052]). Yoon teaches that the etching process can be conducted with a temperature set to be in the range of 50-150°C (Paragraph [0097]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Lee by using a temperature for the process with the range taught by Yoon.
One of ordinary skill the art would have been motivated to make this modification because Lee teaches that the etching temperature used will affect the etching selectivity and the etching rate. Additionally, this modification would have been obvious as it could be considered the combination of prior art elements according to known methods to yield predictable results. This combination would have had the predictable result of supplying a suitable temperature for use in a plasma etching process to etch and metal containing layer. See MPEP 2143(I)(A).
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Lee, as applied to claim 1 above, and further in view of Raley et al. (US-20230260801-A1).
Regarding Claim 10, Lee teaches all the limitations of claim 1 as outlined above.
Lee fails to teach wherein the feature in the layer of metal-containing hardmask material is characterized by a critical dimension of less than or about 20 nm.
Raley teaches methods related to processing a substrate (Paragraph [0002]). Raley teaches a method where a hard mask that can comprise tungsten is etched to form a recess (Paragraphs [0025-000029] Figures 1A and 1B hard mask layer (element 140) can comprise tungsten and is etched to form recesses (element 155)). Raley teaches that the critical dimension of the recess can be 8-40nm (Paragraph [0029]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Lee by selecting as a critical dimension for the feature etched in the metal-containing layer, a critical dimension within the range taught by Raley.
This modification would have been obvious as it can be considered the combination of prior art elements according to known methods to yield predictable results. Lee teaches a method of etching a feature in a metal-containing layer, but does not teach the critical dimension of feature etched, while Raley teaches a critical dimension that can be etched into a metal-containing feature. This combination would have had the predictable result of setting a particular critical dimension for the feature etched. See MPEP 2143(I)(A).
It would have been obvious to one of ordinary skill in the art to have selected and incorporated a critical dimension of the feature at a level within the disclosed range of 8-40nm, including at amounts that overlap with the claimed range of less than or about 20nm. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I).
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Yoon, as applied to claims 13 and 14 above, and further in view of Liu et al. (US-20220382772-A1) and Leung et al. (WO-2022231815-A1).
Regarding Claim 15, Yoon teaches all the limitations of claims 13 and 14 as outlined above.
Yoon further teaches that one or more halogen-containing precursors can be supplied with the boron-and-halogen precursor, and that CF4 and CHF3 can be used as the additional halogen-containing precursors (Paragraph [0052]).
Yoon fails to teach wherein a flow rate ratio of the one or more halogen-containing precursors relative to the boron-and-halogen-containing precursor is greater than or about 50:1.
Leung teaches method relating to semiconductor processes (Paragraph [0002]). Leung teaches a method of etching photomask layers that comprise a plasma etching process where the etching gas comprises a first fluorine-containing precursor and a second halogen-containing precursor (Paragraphs [0006-0008]). Leung teaches that the first fluorine-containing precursor can be CF4 or CHF3 and that the second-halogen-containing precursor can be BCl3 (Paragraph [0046]). Leung teaches that the flow rate ratio between the first fluorine-containing precursor and the second halogen-containing precursor can be greater than 10:1 (Paragraph [0048]).
Liu teaches a method of plasma etching where the etching gases used include BCl3 and fluorine-containing gas ([Abstract]). Liu teaches that by adjusting the flow rate ratio of the gases used during etching the desired etching rate and desired shaped created by the etching process can be achieved (Paragraph [0044]).
It would have been obvious to one of ordinary skill in the art to have modified the method of Yoon by adjusting the flow rate ratios of the etching gases such that a selection was made of a flow rate ratio of CF4 and/or CHF3, which can be considered the one or more halogen-containing precursors, relative to BCl3, which can be considered the boron-and-halogen-containing precursor, to be within the flow rate ratio range taught by Leung.
One of ordinary skill in the art would have been motivated to make this modification because the Liu teaches that the flow rate ratios are result effective variable. Specifically, Liu teaches that the etching rate and the etching shape created depend on flow rate ratio of the etching gases used in the process. Since this particular parameter is recognized as result-effective variable, i.e. a variable which achieves a recognized result, the determination of the optimum or workable ranges of said variable can be characterized as routine experimentation. See In re Boesch, 617 F. 2d 272, 205 U.S.P.Q. 215 (C.C.P.A. 1980). Additionally, this modification would have been obvious as it can be considered the combination of prior art elements according to known methods to yield predictable results. Yoon teaches the use of a multiple gases within the etching gas provided, while Leung teaches a suitable flow rate ratio of multiple gases in a similar etching process. This combination would have had the predictable result of providing a flow rate ratio suitable for completing the etching process as desired. See MPEP 2143(I)(A)
It would have been obvious to one of ordinary skill in the art to have selected and incorporated a flow rate ratio at a level within the disclosed range of greater than 10:1, including at amounts that overlap with the claimed range of greater than or about 50:1. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Yu et al. (US-20080160771-A1) teaches a method of etching metal layer utilizing a process gas that comprises BCl3 and O2 (Paragraphs [0037-0040]).
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANDREW KEELAN LAOBAK whose telephone number is (703)756-5447. The examiner can normally be reached Monday - Friday 8:00am - 5:30pm.
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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.
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/A.K.L./Examiner, Art Unit 1713 /DUY VU N DEO/Primary Examiner, Art Unit 1713
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