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 Rejections - 35 USC § 112
The previous rejection under 35 USC 112(b) has been overcome by amendment.
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 1-9, 11-12, 14-20 are rejected under 35 U.S.C. 103 as being unpatentable over Hsu et al. (US 20200057363 A1), herein referred to as Hsu 1, in view of Hsu et al. (US 20210033960 A1), herein referred to as Hsu 2, as evidenced by Houmes et al. (Chem. Mater. 1996, 8, 2551-2553).
Hsu 1 teaches fabricating a photomask comprising of forming a protection layer over a substrate; a plurality of multilayers of reflecting films are formed over the protection layer; a capping layer is formed over the plurality of multilayers; an absorption layer is formed over capping layer; a first photoresist layer is formed over portions of absorption layer; portions of the first photoresist layer and absorption layer are patterned, forming first openings in absorption layer wherein the first openings expose portions of the capping layer (abstract). The photoresist layer 202 functions with the same purpose as the hard mask of the instant application, wherein the photoresist layer 202 is formed over the light-absorbing layer (absorption layer 110) and is patterned using desired patterning techniques such as electron-beam lithography, photolithography, or any other suitable process [0023] and the absorption layer 110 is etched to form a first opening 204, exposing portions of the capping layer 108 [0023] (claim 1). The capping layer 108 is composed of a material such as ruthenium (Ru), ruthenium nitride (RuN), ruthenium Oxide (RuO), RuNb rich with Nb [0021].
However, Hsu 1 fails to teach performing a treatment to convert the top portion into a ruthenium nitride (RuN) layer (claim 1) wherein the treatment is a nitriding reaction using a plasma treatment (claims 6 and 7).
Hsu 2 teaches an extreme ultraviolet lithography (EUVL) mask, a method of treating the EUVL mask with nitrogen plasma, and a method of forming the EUVL mask consisting of a substrate, a reflective multilayer over the substrate, a capping layer over the reflective multilayer, and an absorber layer over the capping layer (abstract) wherein the capping layer 230 includes ruthenium (Ru) or Ru compounds such as ruthenium boron (RuB), ruthenium silicon (RuSi), ruthenium nitride (RuN) ruthenium oxide (RuO2), or ruthenium niobium oxide (RuNbO) [0026] (claims 1, 9, and 15). Referring to FIG. 1B, the absorber layer 250 is patterned with one or more photolithography processes to form a trench 251, wherein a top portion of the capping layer 230 is exposed [0028] (claim 9). Method 318 (Fig. 2A) teaches treating the exposed capping layer of trench 251 with O2 plasma to generate a metal oxide layer, RuO [0045], and is then treated with N2 plasma [0047] (claims 1 and 9). Further, Hsu 2 teaches the lithography process may also include a post exposure bake (PEB), a post-develop bake (PDB), or a combination [0022].
However, Hsu 2 fails to namely teach the N2 plasma reaction to be a nitriding reaction using a plasma treatment (claims 1, 6-7, and 9).
Houmes et al. teaches the use of N2 plasma for nitriding metal oxides wherein TiO2 was heated under a N2/H2 plasma and resulted in the production of TiN (pg. 2551, left column, last paragraph) with the synthetic technique being applicable for other oxide starting materials to produce bulk nitrides (pg. 2552-2553, left column, last paragraph) (claims 1, 6-7, 9, and 15).
It would have been obvious to one of ordinary skill in the art at the time to have combined the photomask of Hsu 1 with the method of patterning and the N2 treatment of Hsu 2 as evidenced by Houmes et al. because the use of N2 plasma for nitridation reactions of oxides “can be easily and quickly converted to a nitride product” (Houmes et al., pg. 2552-2553, left column, last paragraph). Therefore, it would have been obvious to incorporate the post-exposure bake [0022] of Hsu 2 during the N2 plasma treatment of the exposed RuO capping layer to yield RuN, as evidenced by Houmes et al. See MPEP § 2143, rationales (A). See also KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007). Furthermore, when the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP § 2112.01(I).
Regarding claim 2, Hsu 2 teaches the absorber layer 250, deposited over the capping layer 230 [0023], is patterned with one or more photolithography processes to form a trench 251 [0028] and extended into the absorber layer 250 [0034] by etching and removing the portions of the absorber layer 250 wherein the trench is etched laterally [0046].
Regarding claims 3, 11-12, 16-18, and 20, Hsu 2 as evidenced by Houmes et al., as applied to claims 1, 9, and 15 above, teaches forming the RuN layer from the N2- treatment of the formed RuO layer in trench 251 atop the capping layer 230 composed of RuO [0026 and 0047] wherein the nitriding reaction causes N atoms to insert into the capping layer 230 protecting the layer from oxidation, thereby including a deoxygenation reaction [0049]. Although Hsu 2 as evidenced by Houmes et al. is silent regarding the shape of the profile of the RuO layer from a cross-sectional view, it would have been obvious to one of ordinary skill in the art at the time that nitriding the top portion of the RuO layer of the capping layer to form a RuN layer would change the shape of the remaining RuO layer. Similarly, though Hsu 2 as evidenced by Houmes et al. is silent regarding the thickness of the RuN layer, it would have been obvious to one of ordinary skill in the art at the time that the RuN layer would have a thickness associated with the overall composition of the capping layer.
Regarding claims 4 and 14, Hsu 2 teaches the N2 plasma treatment removes surface contamination, such as carbon, thereby preventing a carbon atom or other contamination from reacting with the RuO capping layer 230 [0081]. Further, forming the RuN layer (Hsu 2 in view of Houmes et al.) over the RuO layer prevents the RuO layer from interacting with any ambient atoms present.
Regarding claim 5, Hsu 2 teaches trench 251 wherein the absorber layer 250 is removed, exposing the capping layer 230, thereby forming two absorbing regions on either side of trench 251 and a reflective region within trench 251 ([0028] and Fig. 1B).
Regarding claim 8, the nitriding reaction time ranges from about 20 to about 240 s [0048]. It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have selected the overlapping portion of the ranges of 100 s to 240 s, as disclosed by Hsu 2 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).
Regarding claim 19, Hsu 2 in view of Houmes et al., as applied to claim 15 and explained above, further teaches the absorber layer 250 includes a layer of TaBO over a layer of TaBN [0026].
Claim 10 are rejected under 35 U.S.C. 103 as being unpatentable over Hsu 1 (US 20200057363 A1) in view of Hsu 2 (US 20210033960 A1) as evidenced by Houmes et al. (Chem. Mater. 1996, 8, 2551-2553) and in further view of Shoki et al. (KR 20140121812 A).
Hsu 1 in view of Hsu 2 as evidenced by Houmes et al. teaches fabricating a photomask, as applied to claim 9 and explained above. Further, Hsu 2 teaches the absorber layer 250 includes a layer of tantalum boron oxide (TaBO) over a layer of tantalum boron nitride (TaBN) [0026] and using a plasma etcher on EUVL mask 200 [0038].
However, Hsu 1 in view of Hsu 2 as evidenced by Houmes et al. fails to teach a first etch gas to etch the TaBO material and a second etch gas different first etch gas to etch the TaBN material (claim 10).
Regarding claim 10, Shoki et al. teaches a multilayer reflection film on a substrate [0001] wherein the absorber layer comprises of a TaBO film and a TaBN film [0192] which are etched using a fluorine-based gas (CF4 gas) and a chlorine gas (Cl2 gas), respectively, to form an absorber layer pattern on the capping layer [0197].
It would have been obvious to one of ordinary skill in the art at the time to have combined the photomask of Hsu 1 in view of Hsu 2 as evidenced by Houmes et al. with the etch gases of Shoki et al. to yield good pattern transfer without any defects [0200]. See MPEP § 2143, rationales (A). See also KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007).
Claim 13 are rejected under 35 U.S.C. 103 as being unpatentable over Hsu 1 (US 20200057363 A1) in view of Hsu 2 (US 20210033960 A1) as evidenced by Houmes et al. (Chem. Mater. 1996, 8, 2551-2553) and in further view of Nam et al. (KR 101579843 B1).
Hsu 1 in view of Hsu 2 as evidenced by Houmes et al. teaches fabricating a photomask, as applied to claim 9 and explained above.
However, Hsu 1 in view of Hsu 2 as evidenced by Houmes et al. fails to teach the method used for nitriding the top portion (claim 13).
Regarding claim 13, Nam et al. teaches a photomask and a method of heat treatment or plasma treatment, such as atmospheric pressure plasma, using one or more gases, such as nitrogen [0055].
It would have been obvious to one of ordinary skill in the art at the time to have combined the photomask of Hsu 1 in view of Hsu 2 as evidenced by Houmes et al. with the atmospheric pressure plasma treatment of Nam et al. because using a surface treatment such as the atmospheric pressure plasma treatment improves adhesion with a resist film disposed thereon [0055]. See MPEP § 2143, rationales (A). See also KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007).
Response to Arguments
Applicant's arguments filed 9/16/25 have been fully considered but they are not persuasive. Applicant argues that the references do not disclose a ruthenium nitride layer. The argument is unconvincing because Hsu ‘960 teaches treating the capping layer (which may be made of ruthenium oxide) with a nitrogen plasma that reacts with top surface of the capping layer [0048]. Houmes explains that the reaction converts the oxide to nitride.
Conclusion
THIS ACTION IS MADE FINAL. 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.
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Lin et al. (US 20210397075 A1) teaches a reflective mask including a substrate, a reflective multilayer, a capping layer, an intermediate layer, and a cover layer (abstract). Lin et al. further teaches the capping layer includes two or more layers of different Ru based materials [0031].
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/MICHAEL B CLEVELAND/Supervisory Patent Examiner, Art Unit 1712
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