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 .
This is the initial office action for US Patent Application No. 18/187529 by Kim et al.
Claims 1-15 are currently pending and have been fully considered.
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
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 1-15 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, Line 9 and Claim 13, Line 9 recite the limitation "formed at the portion where the protective layer is exposed". There is insufficient antecedent basis for this limitation in the claims.
Claim 1, Line 13 and Claim 13, Line 13 recite the limitation "second intagliated part formed at the other where the protective layer is exposed". There is insufficient antecedent basis for this limitation in the claims. Also, it is unclear what is meant by “at the other”.
Claims 2-12, 14 and 15 are concurrently rejected because they depend from rejected claims 1 and 13.
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.
Claims 1, 2, 4 and 13-15 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (US 2021/0318608 A1), herein referred to as Kim, in view of Shiobara (US 2021/0072634 A1).
Regarding claims 1 and 13, Kim teaches (Figure 3) a phase shift mask (photomask) for extreme ultraviolet lithography.
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As seen in Figure 3 of Kim, the phase shift mask includes a conductive layer (feature 110); a substrate disposed on the conductive layer (feature 100); a multilayer comprising different metals alternately stacked on the substrate (feature 120); a protective layer disposed on the multilayer (feature 130); and a low-reflectance part (feature 150) disposed on a portion of the protective layer, wherein the low-reflectance part comprises a first absorbent layer (feature 152) disposed on the portion of the protective layer, a low-reflectance layer (feature 154) formed on the first absorbent layer, and a first intagliated part (openings denoted by feature 150P) formed at the portion where the protective layer is exposed.
With further regard to claim 13, Kim teaches the phase shift mask described above and also teaches [0028] the multilayer comprises alternately stacked layers of molybdenum and silicon.
Kim does not appear to explicitly teach the limitations of claims 1 and 13 directed to a photomask for extreme ultraviolet lithography that includes a high-reflectance part disposed on another portion of the protective layer, wherein the high-reflectance part comprises a second absorbent layer disposed on the other portion of the protective layer, a high-reflectance layer disposed on the second absorbent layer, and a second intagliated part formed at a different portion where the protective layer is exposed. However, from the same field of technology, Shiobara discloses [0017] the formation of a reflective mask for EUV lithography applications.
In view of claims 1 and 13, Shiobara teaches (Figure 3) a reflective mask comprising higher reflecting pattern regions.
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As seen in Figure 3 above, Shiobara teaches [0052] reflective patterns (features IP1) formed in region 1a11 comprising a capping layer (feature 26) which includes a reflective material such as ruthenium. The reflective patterns formed in region 1a11 are positioned on protective layer (feature 23) in a region that is different from absorber patterns 30 positioned in region 1a12. A recessed portion HP1 is formed between the reflective patterns and is considered to be analogous to a second intagliated part as recited in claims 1 and 13.
At the time of the filing date of the instant application, it would have been obvious to one of ordinary skill in the art to modify the phase shift mask taught by Kim to include the teachings of Shiobara directed to forming reflective patterns on a reflective mask that are positioned in a region over a protective layer separate from absorber patterns in order to devise a photomask for EUV lithography applications that produces high resolution patterns with reduced optical interference effects.
Regarding claim 2, the combination of Kim and Shiobara teaches (Kim [0028]) the multilayer comprises alternately stacked layers of molybdenum and silicon.
Regarding claim 4, the combination of Kim and Shiobara teaches (Kim [0030]) the protective layer (capping layer) comprises ruthenium.
Regarding claim 14, the combination of Kim and Shiobara teaches (Kim [0028]) the number of alternating layers that constitute the multilayer is between 40 and 60 layers.
Regarding claim 15, the combination of Kim and Shiobara teaches (Kim [0028]) the number of alternating layers that constitute the multilayer is between 40 and 60 layers. The range taught by Kim and Shiobara overlaps the claimed range of 50 to 160 layers and therefore, a prima facie case of obviousness exists (MPEP Chapter 2144.05).
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (US 2021/0318608 A1), herein referred to as Kim, in view of Shiobara (US 2021/0072634 A1) as applied to claim 1, and further in view of Tanady et al. (US 2022/0121101 A1), herein referred to as Tanady.
The combination of Kim and Shiobara does not appear to explicitly teach the limitations of claim 3 directed to the film thicknesses of the layers that constitute the multilayer. However, from the same field of technology, Tanady discloses an extreme ultraviolet mask.
In view of claim 3, Tanady teaches [0068] the thickness of each Mo/Si pair, comprised of a Mo layer and a Si layer, is from about 2 nm to about 7 nm. Based on the ranges of thicknesses recited in claim 3, the first and second layers would have a combined thickness of 3 to 11 nm when the first and second layers are formed in pairs. Therefore, the thickness range for the Mo/Si pair taught by Tanady overlaps the claimed range and therefore a prima facie case of obviousness exists (MPEP Chapter 2144.05).
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (US 2021/0318608 A1), herein referred to as Kim, in view of Shiobara (US 2021/0072634 A1) as applied to claim 1, and further in view of Shoki et al. (US 2022/0121102 A1), herein referred to as Shoki.
The combination of Kim and Shiobara does not appear to explicitly teach the limitations of claim 5 directed to the protective layer thickness. However, from the same field of technology, Shoki discloses a reflective mask for EUV lithography applications.
In view of claim 5, Shoki teaches [0080] a protective film for a reflective mask having a thickness in the range of 1.5 nm to 6 nm. The protective film thickness range taught by Shoki overlaps the claimed range and therefore a prima facie case of obviousness exists (MPEP Chapter 2144.05).
Claims 6-9 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (US 2021/0318608 A1), herein referred to as Kim, in view of Shiobara (US 2021/0072634 A1) as applied to claim 1, and further in view of Lin et al. (US 2021/0063865 A1), herein referred to as Lin.
The combination of Kim and Shiobara does not appear to explicitly teach the limitations of claims 6-9. However, from the same field of technology, Lin discloses an extreme ultraviolet mask.
In view of claims 6-9, Lin teaches [0031] an extreme ultraviolet mask comprising an anti-reflection layer disposed over an absorber layer. The anti-reflection layer can include a metal oxide such as tantalum oxide which is known to have reflective properties.
At the time of the filing date of the instant application, it would have been obvious to one of ordinary skill in the art to modify the phase shift mask taught by Kim and Shiobara to further include the teachings of Lin directed to employing metal oxide anti-reflective layers on an extreme ultraviolet mask because such layers are known in the art to provide improved pattern resolution while reducing unwanted stray light effects that cause critical dimension variations when patterns on the mask are exposed to EUV light.
Claims 10-12 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al. (US 2021/0318608 A1), herein referred to as Kim, in view of Shiobara (US 2021/0072634 A1) as applied to claim 1, and further in view of Ishibashi et al. (US 2008/0248409 A1), herein referred to as Ishibashi.
The combination of Kim and Shiobara does not appear to explicitly teach the limitations of claims 10-12. However, from the same field of technology, Ishibashi discloses the formation of a reflective mask.
In view of claims 10-12, Ishibashi teaches [0085] a reflective mask comprising a low-reflectivity layer as a light absorbing layer wherein the light absorbing layer may include tantalum nitride. Ishibashi further teaches [0108] the light absorbing layer comprises an upper light absorbing layer and a lower light absorbing layer and that the thicknesses of the upper and lower light absorbing layers can be adjusted to optimize the light absorbing properties thereof.
At the time of the filing date of the instant application, it would have been obvious to one of ordinary skill in the art to modify the phase shift mask taught by Kim and Shiobara to further include the teachings of Ishibashi directed to forming absorbing layers with different light absorbing properties because such layers are known in the art to provide improved pattern resolution while suppressing blurring defects at pattern edge portions when patterns on the mask are exposed to EUV light.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to STEWART A FRASER whose telephone number is (571)270-5126. The examiner can normally be reached M-F, 7am-4pm, EST.
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/STEWART A FRASER/Primary Examiner, Art Unit 1724