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 Status
Claims 1-20 are under consideration.
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 1-20 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.
Claim 1 recites the limitation "selectively dry etching first portions of the metal-free polymer film using an etch gas in the processing chamber to form a plurality of features comprising the remaining second portions". There is insufficient antecedent basis for “the remaining second portions” in the claim.
Claim 19 recites the limitation "wherein an etch rate of the exposed region is greater than an etch rate of a region that is masked". There is insufficient antecedent basis for "the exposed region" in the claim.
Claim 16 recites the limitation "wherein an etch rate of the masked region is greater than an etch rate of the exposed region", which is unclear. "The exposed region" could be interpreted to refer to either the region exposed to plasma or the region exposed to EUV irradiation, which are two different regions. For the sake of examination, the examiner will interpret “the exposed region" as the region exposed to EUV irradiation.
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.
The factual inquiries 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.
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 1-2, 4-8, and 14-16 are rejected under 35 U.S.C. 103 as being unpatentable over Park (US20160159974A1, published 2016).
Regarding claims 1-2, 4-8, and 14-16,
Park teaches spin-coating (spin-on process) a photoresist layer onto an underlying layer [0108], where an EUV exposure is performed on a photoresist layer where unexposed portions may be removed by dry etching (dry developing, negative tone) [abstract, 0032, 0037], reading on instant claim 15.
Park teaches the photoresist polymer may include a carbon chain, without mention of a metal-containing moiety [00075-0084].
Park teaches a decarboxylation reaction caused by a photo-chemical reaction induced by an EUV exposure process [0098, 0086], reading on instant claim 8.
Park teaches dry etching to remove unexposed portions of the resist layer and further transferring the pattern into an underlayer using the same process chamber [0175-0179], forming a plurality of features in the unetched portions [fig 11], and may be performed using a plasma [0139], reading on instant claims 2, 6, and 14.
Park teaches Ohnish (onishi) parameter for etch resistance, which is a function of (Total number of atoms)/{(Number of carbon atoms)−(Number of oxygen atoms)}. As a value of the Ohnish parameter calculated by the Experimental Equation becomes larger, the etch-resistance with respect to the dry etching process may be reduced. Conversely, when the value of the Ohnish parameter is decreased, the etch-resistance may be increased [0133-0134].
Park teaches etching rates of the exposed portion and the non-exposed portion may be different from each other because of the differences in chemical structures. Various patterns may be formed using the photoresist polymer based on the difference of the etching rates [0100].
While silent to the explicit Ohnishi parameter values, it would have been obvious to a person of ordinary skill in the art that the portions removed by dry etching would have a significantly higher Ohnishi parameter, such as a factor of 2, to ensure a sufficient difference in etching rate between exposed and unexposed regions during dry etching, reading on instant claim 7.
Regarding the instant claim limitation “wherein a pitch of the plurality of features is below the feature size achievable with a 193nm immersion lithography tool in a single patterning process”, it would be obvious to a person of ordinary skill in the art that EUV exposure (~13nm), with a much lower wavelength, would be capable of forming a pitch lower than what is achievable with a 193nm immersion lithography tool in a single patterning process, reading on instant claims 1 and 16.
It would have been obvious to a person of ordinary skill that while dry etching is in progress, by-products would be expected to be formed, thus changing the composition of the etch gas. Further, it would be obvious to a person of ordinary skill in the art that adjustments to the etch gas composition may be made across multiple processing steps in an effort to optimize the etch process in forming desired pattern dimensions and shapes, as well as control line edge or width roughness, reading on instant claim 4.
Park teaches in example embodiments, a photoacid generator (PAG) may be excluded from the photoresist composition. Accordingly, the exposed portion may be formed only by the photo-chemically induced elimination reaction without an intermediation of an acid (proton: H+) in the exposure process [0120]. However, Park does not teach that a PAG must be excluded. It would have been obvious to a person of ordinary skill in the art to try including a PAG in an effort to further optimize the composition, reading on instant claim 5.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Park (US20160159974A1, published 2016) as applied to claim 1 above, and further in view of Katsumata (US20080076261A1, published 2008).
Regarding claim 3,
Park teaches the above limitations set forth.
Katsumata, analogous art, teaches a patterning process [0011] including a step of etching an organic lower resist layer [0054, 0061], where the etching gas may contain O2, H2, and CO.
As both teach dry etching a resist layer using a plasma, it would be obvious to a person of ordinary skill in the art that using the etching gas of Katsumata as the etching gas of Park would result in a comparable and expected dry etching process, reading on instant claim 3. Further, it would be obvious to a person of ordinary skill in the art to adjust the etching gas components in order to optimize the dry etching process.
Claims 1-2, 5, 10, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Hirano (US20180239255A1, published 2018).
Regarding claims 1-2, 5, 10, and 15,
Hirano teaches a pattern forming process comprising steps of applying a chemically amplified positive resist composition comprising (A) a base resin, (B) a photoacid generator, (C) an organic solvent, and (D) a polyvinyl alcohol or polyvinyl alkyl ether onto a substrate to form a resist film thereon, (ii) exposing the resist film to radiation, and (iii) dry etching the resist film with an oxygen-containing gas for development [abstract], reading on instant claim 5.
Hirano teaches examples of their base resin (polymer A) which are metal-free [0025, 0052].
Hirano teaches spin coating their resist composition onto the substrate, which may include antireflective coatings [0114], reading on instant claim 15.
While Hirano is silent to etching the substrate, they do teach using the resulting photoresist pattern, a circuit forming step including plating, sputtering, evaporation or the like may be carried out to form a semiconductor substrate [0131].
It would be obvious to a person of ordinary skill in the art that a subsequent etching step (patterning), such as into an underlying antireflective coating, may be performed in an effort to form a circuit (which would be expected to contain a plurality of features) [0131].
Hirano teaches a sufficient difference in etching rate between exposed and unexposed regions during dry etching in a process chamber using an oxygen gas plasma where the resist film in the unexposed region is left behind, yielding a positive pattern [0086, 0130], reading on instant claims 2 and 10.
Regarding the instant claim limitation “wherein a pitch of the plurality of features is below the feature size achievable with a 193nm immersion lithography tool in a single patterning process”, it would be obvious to a person of ordinary skill in the art that EUV exposure (~13nm), with a much lower wavelength, would be capable of forming a pitch lower than what is achievable with a 193nm immersion lithography tool in a single patterning process, reading on instant claim 1.
Claims 11-12 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Hirano (US20180239255A1, published 2018) as applied to claims 1 and 10 above, and further in view of Park (US20160159974A1, published 2016).
Regarding claims 11-12 and 19,
Hirano teaches the above limitations set forth.
Park, analogous art, teaches an Ohnish (onishi) parameter for etch resistance, which is a function of (Total number of atoms)/{(Number of carbon atoms)−(Number of oxygen atoms)}. As a value of the Ohnish parameter calculated by the Experimental Equation becomes larger, the etch-resistance with respect to the dry etching process may be reduced. Conversely, when the value of the Ohnish parameter is decreased, the etch-resistance may be increased [0133-0134].
As both teach dry etch development processes, it would have been obvious to a person of ordinary skill in the art that the portions removed by dry etching would have a significantly higher Ohnishi parameter, such as a factor of 2, to ensure a sufficient difference in etching rate between exposed and unexposed regions during dry etching as desired by Hirano [0086], reading on instant claim 11.
Further, as the exposed portions are rendered dry developable, where the Ohnishi parameter is expected to increase, the number of oxygen atoms would be expected to increase in order to ensure a sufficient difference in etching rate between exposed and unexposed regions during dry etching as desired by Hirano, reading on instant claim 12 and 19.
Claims 1-2, 4-6, 9, and 14-15 are rejected under 35 U.S.C. 103 as being unpatentable over Lee (US20020061461A1, published 2002) in view of Park (US20160159974A1, published 2016).
Regarding claims 1-2, 4-6, 9, and 14-15,
Lee teaches a photoresist composition comprising of a polymer of formula 1 (metal-free) [abstract, claim 1], where exposure may be made with an EUV light source.
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Lee teaches coating their photoresist composition onto a substrate to form a photoresist film, selectively exposing the photoresist film, and etching the non-exposed portion of the photoresist film to form a plurality of features in the unetched portions [0046-0048, fig 1, 0011], which implies the etch rate of the etched portions would necessarily be greater that unetched portions, reading on instant claim 6.
Lee teaches the photoresist may be spin-coated (spin-on process) [0074], reading on instant claim 15.
Regarding the instant claim limitation “wherein a pitch of the plurality of features is below the feature size achievable with a 193nm immersion lithography tool in a single patterning process”, it would be obvious to a person of ordinary skill in the art that EUV exposure (~13nm), with a much lower wavelength, would be capable of forming a pitch lower than what is achievable with a 193nm immersion lithography tool in a single patterning process.
Lee teaches the dry development (etching) step is performed in a (process) chamber using an O2 plasma [0056, 0074], reading on instant claim 2.
Lee teaches their dry development process includes breakthrough, etching, and over-etching steps [0074]. It would have been obvious to a person of ordinary skill in the art that the separate steps may include different etch gas compositions, in an effort to optimize the different etch processes. Additionally, as etching in progress, by-products would be expected to be formed, thus changing the composition of the etch gas. Further, it would be obvious to a person of ordinary skill in the art that adjustments to the etch gas composition may be made across multiple processing steps in an effort to optimize the etch process in forming desired pattern dimensions and shapes, as well as control line edge or width roughness, reading on instant claim 4.
Lee teaches including a photoacid generator [claim 8], which would be expected to generate an acid during EUV exposure and further react with acid labile groups in the polymer [0021], reading on instant claim 5.
Lee fails to teach subsequently etching an underlying layer.
Park, analogous art, teaches dry etching to remove unexposed portions of the resist layer and further transferring the pattern into an underlayer using the same process chamber [0175-0179], reading on instant claims 1 and 14.
As both teach dry development processes, it would have been obvious to a person of ordinary skill in the art that the dry developed resist pattern of Lee could be used to further etch an underlying layer as taught by Park in an effort to reduce manufacturing costs associated with separate processing steps.
While Lee is silent to cyclizing the exposed polymer, it would be obvious to a person of ordinary skill in the art that the polymer of Lee may further crosslink with itself, which may result in additional rings formed between two polymer chains, which may interpreted as cyclizing the polymer, reading on instant claim 9.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. US20040169009A1 teaches a dry development method using silicon-containing resist film (may be considered non-metallic) which may be positive or negative. US 4307178 A teaches an organic photoresist layer developed by plasma (dry etching), which may be positive or negative.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Alexander Lee whose telephone number is (571)272-2261. The examiner can normally be reached M-Th 7:30-5:30 EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Mark Huff can be reached at (571) 272-1385. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/A.N.L./Examiner, Art Unit 1737
/JONATHAN JOHNSON/Supervisory Patent Examiner, Art Unit 1734