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 .
Response to Arguments
Applicant’s cancelation of claims 22-23 and addition of claims 24-25 is acknowledged.
Applicant’s arguments, see pages 9-10, filed 8 July 2026, with respect to the rejection(s) of claim(s) 1 and 7, as well as their dependent claims, under 35 U.S.C. 103 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of US 20210397075 A1 (hereby referred to as Lin).
Applicant has amended independent claims 1 and 7 to remove tantalum (Ta) as one of the additive elements included in the absorber film. Several dependent claims have been amended to change the additive element from tantalum (Ta) to alternative elements. Applicant argues that the previously cited prior art (Hsu) fails to teach or disclose an iridium-based absorber film comprising an additive element selected from boron (B), silicon (Si), phosphorus (P), titanium (Ti), germanium (Ge), arsenic (As), selenium (Se), niobium (Nb), molybdenum (Mo), and ruthenium (Ru). Upon review of the previously cited prior art, the Examiner finds the Applicant’s arguments persuasive, as Hsu only teaches absorber layers comprising iridium in combination with tantalum, and not iridium in combination with any of the aforementioned elements. Therefore, the previous rejection has been withdrawn. However, a new rejection is presented in view of US 20210397075 A1 (hereby referred to as Lin), as explained below.
Claim Rejections - 35 USC § 103
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, 3, 5, 7, 11, 13, 15, 18, and 24-25 are rejected under 35 U.S.C. 103 as being unpatentable over US 20210397075 A1 (hereby referred to as Lin).
The Examiner notes that the instant application claims priority from JP2020-217573, which has a filing date of 25 December 2020. Lin has a filing date of 01 December 2020 and thus qualifies as prior art under 35 U.S.C. 102(a)(2).
Regarding Claims 1 and 7, Lin teaches EUV photomasks and manufacturing methods thereof. The EUV photomask is formed from an EUV photomask blank, which comprises a substrate, a multilayer Mo/Si stack (a multilayer reflective film), and an absorber layer (Lin, paragraph 0023 and Fig. 1B). The EUV photomask is formed by patterning the absorber layer of the photomask blank (Lin, paragraph 0085). The absorber layer may be a tantalum-based material, a chromium-based material, an iridium-based material, a ruthenium-based material, or a platinum-based material (Lin, paragraph 0032). Examples of the iridium-based material include IrRu, IrSi, or IrTi (Lin, paragraph 0032). Lin explains that the term “X based” (wherein X is an element such as tantalum, chromium, iridium, etc.) means that element “X” is present in the material at an amount of 50 atomic% or more (Lin, paragraph 0032). Thus, an iridium-based material comprises 50 atomic% or more Ir. Lin does not provide an inventive example wherein the aforementioned iridium-based absorber layer is utilized. However, one having ordinary skill in the art would find a reflective mask blank comprising an absorber film comprising iridium (Ir) with ruthenium (Ru), silicon (Si), or titanium (Ti), wherein the Ir content is 50 atomic% or more, an obvious variant of Lin’s disclosure. Similarly, the reflective mask is produced by patterning the absorber layer (Lin, paragraph 0085). Thus, the broader disclosure of Lin renders obvious the invention of instant claims 1 and 7. Refer to MPEP 2143 I. B and/or 2143 I. E.
Regarding Claims 3, 11, 13, 18, and 24-25, Lin renders obvious the reflective mask blank and reflective mask of independent claims 1 and 7, respectively, as explained above. Lin states that the iridium content of the iridium-based absorber layer is 50 atomic% or more (Lin, paragraph 0032). Lin does not explicitly state the content of the additive element. However, Lin further teaches that the absorber layer may be represented by AxBy, wherein A and B are one or more of Ir, Pt, Ru, Cr, Ta, Os, Pd, Al, or Re and x:y is from 0.25:1 to 4:1 (Lin, paragraph 0033). For instance, the absorber layer may comprise IrxRuy, wherein the ratio of x:y may yield an Ir content of 50 atomic% or more and a Ru content of 2 to 49 atomic%. The absorber layer may further include Si, B, or N in an amount of up to 10 atomic% (Lin, paragraph 0033). Thus, the content amounts recited by instant claims 3, 11, 13, 18, and 24-25 are obvious in view of Lin’s broader disclosure.
Regarding Claims 5 and 15, Lin teaches that an intermediate layer may be formed under the absorber layer (Lin, paragraph 0040 and Fig. 2A). The intermediate layer functions as an etching stop layer and thus is analogous to a buffer layer (Lin, paragraph 0040). The intermediate layer may be formed of chromium-based materials (Lin, paragraph 0040).
Regarding Claims 6 and 16, Lin teaches that the intermediate layer has a thickness of about 0.5 nm to 5 nm (Lin, paragraph 0042). Lin further teaches that the absorber layer has a thickness of 25 nm to 100 nm (Lin, paragraph 0034). The thickness range of the absorber layer overlaps with the thickness range recited by instant claims 6 and 16, and thus a prima facie case of obviousness exists. Refer to MPEP 2144.05 I.
Regarding Claims 20-21, Lin teaches that the mask blank comprises a hard mask layer over the absorber layer (Lin, paragraph 0023 and Fig. 1B). The hard mask layer is analogous to the claimed etching mask film. The hard mask layer may be made of a chromium-based material, such as CrO, CrON, or CrCON (Lin, paragraph 0037). As the hard mask layer may be made of a different chromium-based material (such as CrCON) than the chromium-based material used for the buffer layer (which may be CrN, refer to paragraph 0040 of Lin), the two layers having different chromium content is obvious in view of Lin’s broader disclosure.
Claim(s) 4, 10, 12, 14, 17, and 19 are rejected under 35 U.S.C. 103 as being unpatentable over US 20210397075 A1 (hereby referred to as Lin) as applied to claims 1 and 7 above, and further in view of US 20140011123 A1 (hereby referred to as Okamura).
Regarding Claims 4, 10, 12, 14, 17, and 19, Lin renders obvious a reflective mask blank and a reflective mask accordingly to instant claims 1 and 7, respectively, as discussed above. However, Lin is silent in regards to an iridium-based absorber layer comprising oxygen in the amount recited by instant claims 4, 10, 12, 14, 17, and 19.
Okamura teaches photomasks and methods of using the same. The photomask comprises a substrate with a multilayer reflection film, a capping layer, a buffer layer, and a light absorber layer formed thereon (Okamura, paragraph 0044 and Fig. 1). Okamura prefers that oxygen is not present in the absorber layer (Okamura, paragraph 0078), but further states that the oxygen content in the absorber layer is preferably less than 25 atomic% (Okamura, paragraph 0079). Okamura recognizes that the oxygen content of the absorber layer has an effect on the etching rate (Okamura, paragraph 0080).
Lin and Okamura are analogous art because both references pertain to reflective masks and their manufacture. It would have been obvious to one having ordinary skill in the art before the filing date of the instant application to include oxygen in the absorber film taught by Lin in an amount within the range of 0 to 25 atomic%, as taught by Okamura, because it has been recognized by the prior art that oxygen content of the absorber layer has an effect on the etching rate during patterning via a dry etching process (see Okamura, paragraph 0080). Thus, one having ordinary skill in the art would be motivated to routinely optimize the oxygen content of the absorber layer, based upon the teachings of Lin and Okamura, in order to obtain a desired etching rate. One having ordinary skill in the art would wish to adjust the etching rate to ensure high accuracy etching whilst simultaneously preventing damage to other layers of the mask structure (see Okamura, paragraph 0079-0080). Refer to MPEP 2144.05 II.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, 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 nonprovisional extension fee (37 CFR 1.17(a)) 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 JAYSON D COSGROVE whose telephone number is (571)272-2153. The examiner can normally be reached Monday-Friday 10:00-18:00.
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, Jonathan Johnson can be reached at 571-272-1177. 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.
/JAYSON D COSGROVE/Examiner, Art Unit 1737
/JONATHAN JOHNSON/Supervisory Patent Examiner, Art Unit 1734
