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 arguments, see pages 7-9, filed 6 March 2026, with respect to the rejection(s) of claim(s) 1-3 and 6-19 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 Therefore, the rejection has been withdrawn.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 20210096456 A1 (hereby referred to as Suzuki).
Applicant has amended independent claims 1-3 and 15. Claim 1 has been amended to remove boron (B) from the list of additive elements. Claims 2 and 15 have been amended to reduce the upper limit on the film density from 14.0 g/cm3 to 12.0 g/cm3. Claim 3 has been amended to remove zirconium (Zr) from the list of additive elements. Applicant argues that the previous rejection of claims 1-3 and 15 should be withdrawn because the previously cited prior art (Mikami) fails to disclose, teach, or otherwise render obvious the reflective mask blanks of claims 1-3 and the method of manufacturing a mask blank according to instant claim 15. Regarding claims 1 and 3, Applicant argues that Mikami fails to disclose or render obvious a reflective mask blank comprising a rhodium-based protective film comprising Rh and one of the elements recited by instant claims 1 and 3, such that the content ratios are satisfied. Upon review of Mikami’s disclosure, the Applicant’s arguments are found persuasive regarding claims 1 and 3, as amended, due to Mikami failing to render obvious the combination of Rh with the elements recited by instant claims 1 and 3. Regarding claims 2 and 15, Applicant argues that since rhodium metal has a density of 12.41 g/cm3, the amendment reducing the upper limit of the film density to 12.0 g/cm3 overcomes the embodiment wherein the protective film comprises only rhodium (Rh). Regarding claims 2 and 15, Applicant’s arguments, in light of the claim amendments, are found to be persuasive. Therefore, the previous rejection is withdrawn. However, a new rejection is presented in view of US 20210096456 A1 (hereby referred to as Suzuki), 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, 6, and 10-14 are rejected under 35 U.S.C. 103 as being unpatentable over US 20210096456 A1 (hereby referred to as Suzuki).
The Examiner notes that Suzuki was published on 1 April 2021 but has a filing date of 23 September 2020, which is earlier than the effective filing date of the instant application. Therefore, Suzuki qualifies as prior art per 35 U.S.C. 102(a)(2).
Regarding Claims 1 and 3, Suzuki teaches a multilayered reflective film provided substrate, a reflective mask blank, a reflective mask, and a method of manufacturing the same. The mask blank comprises a substrate (1), a multilayered reflective film (5), a protective film (6), and an absorber film (7) (Suzuki, paragraph 0046 and 0048, see Fig. 3). The multilayered reflective film reflects EUV light (Suzuki, paragraph 0066) and the absorber film absorbs EUV light (Suzuki, paragraph 0109). The protective film enables inhibition of damage of the surface of the multilayered reflective film (Suzuki, paragraph 0073). The protective film includes ruthenium (Ru) and an additive material, wherein the additive material may be rhodium (Rh) (Suzuki, paragraph 0074). The content of the additive material may be up to 50 atomic% (Suzuki, paragraph 0075). In particular, when the protective film is a RuRh film, the rhodium concentration is 15 atomic% to 50 atomic% (Suzuki, paragraph 0081). It is preferable that the protective film including Ru and Rh further includes nitrogen (N) (Suzuki, paragraph 0089). When the protective film includes nitrogen (N), the content of nitrogen in the protective film is preferably larger than 1 atomic% and 20 atomic% or less, and more preferably 3 atomic% or more and 10 atomic% or less (Suzuki, paragraph 0098).
Suzuki fails to disclose a specific example wherein the reflective mask blank comprises rhodium (Rh) and one of the additive elements recited by instant claim 1, wherein the protective film comprises a Rh content of 40 atomic% or more and 99 atomic% or less and at least one element selected from the group consisting of N, O, and C at a content of 1 atomic% or more and 60 atomic% or less. However, the broader disclosure of Suzuki teaches a protective film comprising ruthenium (Ru) and rhodium (Rh), wherein the rhodium content can be as high as 50 atomic%. Suzuki further teaches that the protective film comprising Ru and Rh further comprises nitrogen (N) having a content of 1 atomic% to 20 atomic%. Thus, Suzuki’s broader disclosure renders the inventions of claims 1 and 3 of the instant application prima facie obvious. Refer to MPEP 2143 I. E. Alternatively, Example 4-3 of Suzuki teaches a protective film comprising 65 atomic% Ru, 30 atomic% Rh, and 5 atomic% N (refer to Table 1 on page 13 of Suzuki). These amounts do not satisfy the contents recited by instant claims 1 and 3. However, Suzuki teaches that the amount of rhodium present can be varied to obtain a desired extinction coefficient of the protective film and provide etching resistance (Suzuki, paragraph 0081). Furthermore, the nitrogen content of the protective film can be varied to achieve a desired decrease in crystallinity, thereby adjusting the etching resistance of the protective film (Suzuki, paragraph 0098). Thus, the protective film of instant claims 1 and 3 is also prima facie obvious because Suzuki provides teaching and motivation to routinely optimize the rhodium, ruthenium, and nitrogen contents of the protective film to achieve desired etching and optical characteristics. Refer to MPEP 2144.05 II.
Regarding Claim 6, Suzuki teaches that the protective film preferably has a thickness of 1.0 to 8.0 nm, and more preferably the thickness is 1.5 nm to 6.0 nm (Suzuki, paragraph 0105).
Regarding Claims 10-11, Suzuki teaches that the absorber film comprises a material selected from the group of palladium (Pd), silver (Ag), platinum (Pt), gold (Au), iridium (Ir), tungsten (W), chromium (Cr), cobalt (Co), manganese (Mn), tin (Sn), tantalum (Ta), vanadium (V), nickel (Ni), hafnium (Hf), iron (Fe), copper (Cu), tellurium (Te), zinc (Zn), magnesium (Mg), germanium (Ge), aluminum (Al), rhodium (Rh), ruthenium (Ru), molybdenum (Mo), niobium (Nb), titanium (Ti), zirconium (Zr), yttrium (Y), and silicon (Si), or any compound thereof (Suzuki, paragraph 0111). Particularly, a tantalum (Ta) compound including light elements like boron (B), nitrogen (N), oxygen (O), or combinations thereof may be used as the absorber film (Suzuki, paragraph 0114).
Regarding Claims 12-13, Suzuki teaches that an etching mask film may be formed on the absorber film (Suzuki, paragraph 0120 and Fig. 4). The etching mask film may be formed of chromium (Cr) or chromium compounds (Suzuki, paragraph 0121). In particular, the chromium compound may be Cr with at least one element selected from N, O, C, and H (Suzuki, paragraph 0121). Examples include CrN, CrO, CrC, CrON, CrOC, CrCN, or CrOCN (Suzuki, paragraph 0122).
Regarding Claim 14, Suzuki teaches that the reflective mask blank is converted to a reflective mask by patterning the absorber film (Suzuki, paragraph 0130 and Fig. 8F).
Claim(s) 7 is rejected under 35 U.S.C. 103 as being unpatentable over US 20210096456 A1 (hereby referred to as Suzuki) as applied to claim 1 above, and further in view of US 20150160548 A1 (hereby referred to as Mikami).
Regarding Claim 7, Suzuki renders obvious a reflective mask blank according to instant claim 1, wherein the protective film comprises Rh, Ru, and N. However, Suzuki is silent in regards to the surface roughness of the protective film.
Mikami teaches a reflective mask blank for EUV lithography. As shown in Fig. 1 of Mikami, the mask blank comprises a substrate (11) having a reflective multilayer film (12) formed upon the substrate, as well as a protective layer (13) formed over the reflective multilayer film and an absorber layer (14) formed over the protective layer (Mikami, paragraph 0041-0042). The layout of the mask blank taught by Mikami matches the layout described by Suzuki. Preferably, the protective layer is formed of a metal such as ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt), or a compound containing one of these metal elements (Mikami, paragraph 0093). Mikami teaches that the surface roughness of the surface of the protective layer is preferably at most 0.3 nm RMS (Mikami, paragraph 0095).
Suzuki and Mikami are analogous art because both references pertain to reflective mask blanks 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 produce a protective film having a surface roughness (RMS) of 0.3 nm or less, as taught by Mikami, in the mask blank taught by Suzuki because such a surface roughness allows for the surface of the absorber layer to be formed on the protective layer to be sufficiently smooth, and thus being free from deterioration of the dimensional precision of the pattern due to edge roughness (Mikami, paragraph 0095).
Claim(s) 8-9 are rejected under 35 U.S.C. 103 as being unpatentable over US 20210096456 A1 (hereby referred to as Suzuki) as applied to claim 1 above, and further in view of US 20160147139 A1 (hereby referred to as Onoue).
Regarding Claims 8-9, Suzuki renders obvious the reflective mask blank according to instant claim 1, as explained above. However, Suzuki is silent in regards to the presence of a diffusion barrier layer disposed between the reflective multilayer film and the protective layer.
Onoue teaches a reflective mask blank for EUV lithography and a reflective mask produced from the same. Onoue teaches a substrate with a multilayer reflective film comprising a substrate (12), a reflective multilayer film (14), a block layer (16), and a protective film (18), in that order (Onoue, paragraph 0076 and Fig. 1). A mask blank is formed by applying an absorber film (20) over the protective layer (18) (Onoue, paragraph 0121 and Fig. 2). The block layer, which is disposed between the protective layer and the reflective multilayer, is made of a material that can prevent the migration of silicon (Si) from the reflective multilayer to the protective film (Onoue, paragraph 0095), and thus acts as a diffusion barrier layer. Examples of suitable materials include metals selected from Ti, Al, Ni, Pt, Pd, W, Mo, Co, and Cu, as well as alloys of two or more of the aforementioned metals, nitrides, silicides, and silicide nitrides thereof (Onoue, paragraph 0095). Onoue explicitly names TiN (titanium nitride) as a suitable block layer material (Onoue, paragraph 0095).
Suzuki and Onoue are analogous art because both references pertain to reflective mask blanks 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 a block layer formed of titanium nitride (TiN) that acts as a diffusion barrier layer, as taught by Onoue, in the reflective mask blank taught by Suzuki because a diffusion barrier layer prevents the migration of silicon from the reflective multilayer to the protective layer (Onoue, paragraph 0093), which mitigates stripping of the film and yields a reflective mask having high reflectance and excellent cleaning resistance (Onoue, paragraph 0094).
Claim(s) 17-19 are rejected under 35 U.S.C. 103 as being unpatentable over US 20210096456 A1 (hereby referred to as Suzuki) as applied to claim 1 above, and further in view of US 20160377769 A1 (hereby referred to as Hamamoto).
Regarding Claims 17-19, Suzuki renders obvious the reflective mask blank according to instant claim 10, as explained above. Suzuki teaches that the absorber film may comprise ruthenium (Ru), tantalum (Ta), and/or tungsten (W) (Suzuki, paragraph 0111). However, Mikami does not teach or suggest the use of a RuW (ruthenium-tungsten alloy) or RuTa (ruthenium-tantalum alloy) absorber layer, and is further silent in regards to the contents of the metals in the absorber film alloy.
Hamamoto teaches a reflective mask blank. The mask blank comprises a substrate (10), a reflective multilayer film (21), a protective film (22), and an absorber layer (24), in that order (Hamamoto, paragraph 0064 and Fig. 3). The material of the absorber film is not particularly limited (Hamamoto, paragraph 0134). Further, the absorber film can be provided with a phase shift function (Hamamoto, paragraph 0136). The absorber film having a phase shift functionality is not particularly limited in terms of material (Hamamoto, paragraph 0137). As the absorber film material, tantalum (Ta) alone or a tantalum-based alloy/compound may be used, or another material may be selected (Hamamoto, paragraph 0137). Alternative materials to Ta include Ti, Cr, Nb, Mo, Ru, Rh, and W, and an alloy containing two or more elements chosen from Ta, Ti, Cr, Nb, Mo, Ru, Rh, and W can be used as the absorber film material (Hamamoto, paragraph 0137).
Suzuki and Hamamoto are analogous art because both references pertain to reflective mask blanks 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 use an absorber film formed of RuW or RuTa, as taught by Hamamoto, in place of the absorber film taught by Suzuki because the absorber materials used by Suzuki (such as TaN, TaB, TaON, and the like, per paragraph 0114 of Suzuki) are taught to be equivalent to alloys formed from Ta, Ru, and/or W for the purposes of forming absorber layers for reflective mask blanks (see Hamamoto, paragraph 0134 and 0137). Furthermore, alloys formed from Ta, Ru, and/or W can provide a phase shift functionality to the absorber layer (Hamamoto, paragraph 0137), which helps reduce shadowing effects for the reflective mask blank (Hamamoto, paragraph 0136). Whilst Hamamoto does not explicitly teach the content ratios recited by instant claims 18 and 19, one having ordinary skill in the art would arrive at the metal element content ratios through routine optimization to achieve a desired EUV light reflectance value and/or a phase difference of the absorber film (Hamamoto, paragraph 0132).
Allowable Subject Matter
Claims 2 and 15-16 are allowed.
The following is an examiner’s statement of reasons for allowance: Independent claims 2 and 15 are directed towards a reflective mask blank and a method of manufacturing a reflective mask blank, respectively. Both claims recite that the reflective mask blank comprises a protective film over the reflective multilayer film of the mask blank, wherein the protective film comprises rhodium (Rh) or a Rh-based compound including an element selected from N, O, C, B, Ru, Nb, Mo, Ta, Ir, Pd, Zr, and Ti. Both claims further recite that the protective film comprises Rh in an amount of 90 atomic% or more and has a film density between 10.0 g/cm3 and 12.0 g/cm3. A search of the prior art was performed, but a singular reference disclosing the mask blank or the method of manufacturing a mask blank was not found. The closest prior art includes US 20210096456 A1 (hereby referred to as Suzuki) and US 20150160548 A1 (hereby referred to as Mikami). Suzuki teaches reflective mask blanks and methods of producing the same. The protective film of Suzuki’s invention may comprise rhodium compounds, such as a combination of rhodium and ruthenium. However, Suzuki fails to teach or suggest an embodiment wherein the protective film comprises rhodium in an amount of 90 atomic% or more. Mikami teaches a reflective mask blank and methods of producing the same. Mikami suggests that the protective layer may be formed of rhodium or compounds thereof. Mikami is silent in regards to rhodium content of the protective film, as Mikami prefers using ruthenium for the protective layer. Nonetheless, Mikami’s disclosure suggests the use of a protective layer comprising just rhodium (see Mikami, paragraph 0093). However, rhodium’s bulk density is known to be 12.41 g/cm3 (refer to the PubChem Compound Summary for Rhodium cited in the office action filed 16 December 2025). Thus, Mikami’s suggestion of a rhodium protective layer similarly fails to satisfy all the limitations of independent claims 2 and 15, due to the density of the produced film not falling within the claimed range. It is apparent from the Applicant’s disclosure (see Example 2, paragraph 0065 of the instant application’s specification), that a rhodium protective layer has a density within the claimed range when different film formation conditions are utilized. Upon review of the prior art, there exists no prior art prior to the effective filing date of the instant application that renders obvious a reflective mask blank (or a method of manufacturing the same) wherein the reflective mask blank comprises a protective layer comprising rhodium or a rhodium compound at a content of 90 atomic% or more and having the claimed film density. Therefore, independent claims 2 and 15 are allowable over the prior art. Claim 16 is allowable due to claim 16 depending from an allowable independent claim.
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”
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
Prosecution Insights