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 .
Response to Amendment
Applicant’s amendments with respect to claims 1, 6, 7, and 9, filed on 07/10/2025, are acknowledged and considered by the examiner. No new matter is introduce by the claim amendments.
Response to Arguments
Applicant’s arguments, see pages 8-9, filed 07/10/2025, with respect to the rejections of claims 1-9 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 Therefore, the rejection has been withdrawn.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 over Ikebe (US 2019/0384158 A1) in view of Liu et al. (US 2021/0341828 A1) and Ikebe (US 2019/0384158 A1) in view of Liu et al. (US 2021/0341828 A1) in further view of Mikami (US 8927179 B2), as further explained below.
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 1-3 and 5-9 are rejected under 35 U.S.C. 103 as being unpatentable over Ikebe (US 2019/0384158 A1) in view of Liu et al. (US 2021/0341828 A1).
Regarding claim 1, Ikebe teaches a reflective mask blank in which a multilayer reflection film that reflects EUV light, a protection film, and an absorber film that absorbs a part of incident EUV light and reflects the remainder of the EUV light are formed in this order on one main surface of a substrate ([83] and Fig. 1) wherein:
the range of reflectance of the surface of the phase film with respect to EUV light to be between 3-20% [72],
the phase shift difference is between 170-190 degrees [72],
the absorber film is a multi-element alloy that “can be obtained by selecting multiple elements from Group A, selecting multiple elements from Group B” [79], defined below as “first, second, and third elemental groups” to each claim element accordingly for clarity; examples of the multi-element alloy include a ternary alloy example of TaPdMo [80] that “can be obtained by selecting, for example, Pd and Ta belonging to Group A and Mo belonging to Group B to obtain a ternary alloys of TaPdMo alloys or NiPdMo alloys” [108]; further, “the reflective mask blank described in any one of Configurations 1 to 7, wherein the alloy is a multi-element alloy containing three or more metal elements” [45]; see below for definitions and explanation of the first, second, and third elemental groups,
each of the metal and metalloid elements from groups A and B are “a group of metal elements for which refractive index n and extinction coefficient k” [73] wherein group B contains metal elements that satisfy the expression (1): k≤0.01, namely Mo, Nb, Zr, Y, and Si herein defined as the “first elemental group” (Fig. 2); group A contains metal elements that satisfy the expression (2): n+2k≥0.99, namely W, Au, Ir, V, Pt, Cr, Ta, Hf, Co, Ni, Sn and Te herein defined as the “second elemental group” (Fig. 2); and Group A and B contain metal elements that satisfy the expression (3): n≤0.89, namely Ru, Rh, and Pd, herein defined as the “third elemental group” [79], teaches using a material comprised of a multi-element alloy containing multiple metal elements for the phase shift alloys can be made by selecting multiple elements from groups A and B, as referenced above, along with examples of ternary alloys that involve exactly one metal from each of the now defined elemental groups.
Regarding claim 2, modified Ikebe teaches the metal or metalloid elements included in the first elemental group (group B, as defined above) are Mo, Nb, Zr, Si and Y ([77], Fig. 2); the metal or metalloid elements included in the second elemental group (group A, as defined above) are W, Au, Ir, V, Pt, Cr, Ta, Hf, Co, Ni, Sn and Te ([77], Fig. 2); and the metal or metalloid elements included in the third elemental group (combination of group A and B, as defined above) are Ru, Rh, and Pd (Fig. 2).
Regarding claim 3, modified Ikebe teaches using a material comprised of a multi-element alloy containing multiple metal elements for the phase shift alloys can be made by selecting multiple elements from groups A and B, as explained above, along with examples of ternary alloys that involve exactly one metal from each of the now defined elemental groups, such as the possibility of using Mo, W, and Ru as metal elements in the phase shift film (absorber film) [79]).
Regarding claim 5, modified Ikebe teaches a conductive film is formed “on a main surface of the substrate 12 (main surface on the opposite side from the side where the back side conductive film 11 has been formed) and reflects exposure light in the form of EUV light”, where the back side conductive film 11 correlates to the claimed “conductive film” [83].
Regarding claims 7-9, modified Ikebe teaches “a method of manufacturing a semiconductor device that uses the reflective mask” (Ikebe [2]) and a conductive film formed on an opposite surface of the substrate [83].
However, Ikebe fails to teach the shift in phase of the reflected light from the absorber film is in a range of 200° to 260° (claims 1 and 7) or 200° to 240° (claims 6 and 9).
Regarding claims 1, 6, 7, and 9, Liu et al. teaches EUV mask blanks comprising a substrate, a multilayer stack of reflective layers on the substrate, a capping layer on the multilayer stack of reflecting layers, and an absorber on the capping layer (abstract). The absorber layer 420 comprises a bilayer wherein: the first layer 420a is of silicon and the second layer 420b is of a material with an extinction coefficient (k value) higher than 0.035 and refractive index (n value) lower than 0.95 [0069]; the absorber 420 is comprised of a range of materials that when used together in the absorber bilayer could achieve close to 215 degrees of phase shift [0073]; and the absorber layers can be three absorber layer pairs in a range of 1 to 40 absorber layer pairs (2 to 80 total layers) [0083]. Further, Table 1 on pg. 7 teaches a TaSbSi system wherein the phase shift ranges from approximately 178 degrees to 216 degrees.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have combined the reflective mask blank of Ikebe with the absorber layer phase shifting degree range of Liu et al. because using an absorber with the disclosed phase shift “could lead to significant improvement in the performance of the mask in terms of depth of focus (DOF), normalized image log slope (NILS) and telecentricity error (TCE) comparing with the state-of-art Ta based absorbers” [0071]. See MPEP § 2143, rationale (A). See also KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007). Further, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have selected 200 degrees to 216 degrees, regarding claims 1 and 6-7, and 9, as the overlapping portion of the phase shifting degree range, as disclosed by the Ha because selection of overlapping portion of ranges has been held to be a prima facie case of obviousness. See MPEP § 2144.05.I. In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d 1362, 1365-66 (Fed. Cir. 1997). Furthermore, it would have been obvious to have selected Ru, W and Mo to form the ternary alloy for the phase shift film of modified Ikebe, as it would simply involve the selection of a different element from each of the first, second, and third elemental groups (Mo for the first group, W for the second group, and Pd for the third group), as mentioned above, which is in line with Ikebe’s teaching of selecting one or more from each of the groups of metals [79]. In picking a combination from multiple lists or possible combinations, it has been held that though a specific embodiment is not taught as preferred makes it no less obvious, also, that the mere fact that a reference suggests a multitude of possible combinations does not in and of itself make any one of those combinations less obvious, see Merck v. Biocraft, 10 USPQ2d 1843 (Fed Cir 1985).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Ikebe (US 2019/0384158 A1) in view of Liu et al. (US 2021/0341828 A1), as applied to claim 1 above, and in further view of Mikami (US 8927179 B2).
Regarding claim 4, modified Ikebe in view of Liu et al. teaches the reflective mask blank of claim 1, as explained above and an example using TaPdMo, as discussed above (Fig.3, [177], example 2). However, Ikebe in view of Liu et al. fails to teach the content of said three kinds of elements selected from the elemental groups is not less than 5 at% (claim 4).
Mikami teaches the ternary alloy TaBSi, which is similar to the claimed invention by using 1 metals and 2 metalloid, where the 1 metal is Ta (listed in the second elemental group) and the two metalloids are B and Si (listed in the first elemental group, including element Mo) are taught in modified Ikebe, as defined in claim 1. Column 13, lines 16-18 teaches the composition ranges of TaBSi where Ta is from 50 to 94 at%, Si is from 5 to 30 at % and B is from 1 to 20 at %. Further, the one target compositional ratio is listed as Ta 80 at%, B 10 at%, Si 10 at% (column 19, lines 32-33 and 46-47).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the invention to take the elemental composition of TaPdMo from modified Ikebe and set the composition ratio as taught by Mikami to be Ta at 80% and Mo at 10% (seeing as both Mo and Si can be selected from the first elemental group). This would result in the Pd of the TaPdMo being 10%, and therefore all the contents have values that fall within the claimed “are not less than 5 at%” range, as claimed. Additionally, the chosen elemental composition ratio range is used to prevent destabilization of discharge or variations in the composition of a film or film thickness (Mikami, section 13, lines 13-15). Using the elemental composition of modified Ikebe as the base product combined with the composition ratio of Mikami is seen as an improvement, as one of ordinary skill in the art would have recognized that applying the known technique would have yielded predictable results and resulted in an improved system (KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007) (see MPEP § 2143(I)(D)). Further, one of ordinary skill in the art could have substituted the composition ratio of Ikebe for the ratio in Mikami, and the results of the substitution would have been predictable (KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007) (see MPEP § 2143(I)(B)).
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 Christine Curiac whose telephone number is (703)756-1375. The examiner can normally be reached M-F 9:00-6:00 ET.
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/CHRISTINE CURIAC/Examiner, Art Unit 1737
/MARK F. HUFF/Supervisory Patent Examiner, Art Unit 1737
