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. 18/692007 by Umezawa et al.
Claims 1-7, 9, 10 and 12-25 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 § 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 1-3, 9, 10, 12, 13, 16, 19, 20 and 23 are rejected under 35 U.S.C. 103 as being unpatentable over Mikami (US 2015/0160548 A1).
Regarding claims 1, 6, 9, 10, 16 and 23, Mikami teaches [0018] a reflective layer-coated substrate for EUV lithography, a reflective mask blank for EUV lithography [0023] that includes the aforementioned reflective layer-coated substrate and a reflective mask for EUV lithography [0143] that is obtained by patterning the absorber layer of the aforementioned reflective mask blank.
As seen in Figure 1 of Mikami, the reflective layer-coated substrate and the reflective mask blank include a substrate 11, a multilayer reflective film 12 positioned on the substrate, a protective layer 13 formed on the multilayer reflective film and an absorber layer 14 formed on the protective layer.
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Mikami proceeds to teach [0041] the multilayer reflective film includes a low refractive index layer (molybdenum (Mo) layer 12c) and a high refractive index layer (silicon (Si) layer 12a) that are stacked in an alternating configuration. Mikami further teaches an intermediate layer (layer 12b) is formed between the low and high refractive index layers. The intermediate layer is disclosed by Mikami to be a thin film that contains silicon (Si) and an additive element nitrogen (N). In addition, the silicon (Si) contained in the intermediate layer is the same material as the material contained in the high refractive index layer.
Mikami does not appear to explicitly disclose the limitation of “the content of the additive element in the multilayer reflective film is 40 atom% or less”.
However, Mikami does teaches [0070] the amount of nitrogen (N) contained in the intermediate layer is preferably in a range of 0.5 to 25 atomic percent. Due to the range of nitrogen (N) taught by Mikami, it would be obvious to one of ordinary skill in the art that the total nitrogen (N) content contained in the multilayer reflective film of Mikami to be less than 40 atomic percent because the constituent low and high refractive index layers of the multilayer film, containing molybdenum (Mo) and silicon (Si) respectively, would lower the overall nitrogen (N) content of the multilayer reflective film. Mikami indicates [0070] that maintaining the amount of nitrogen (N) contained in the intermediate layer between 0.5 and 25 atomic percent is advantageous to suppress mixing of elements at the interfaces of the low and high refractive index layers of the multilayer film while also ensuring sufficient reflectivity of the multilayer film. Therefore, claims 1, 6, 9, 10, 16 and 23 would have been obvious at the time of the filing date of the present application.
Regarding claims 2, 12 and 19, Mikami as discussed above, teaches the amount of nitrogen (N) contained in the intermediate layer is preferably in a range of 0.5 to 25 atomic percent. Due to the range of nitrogen (N) taught by Mikami, it would be obvious to one of ordinary skill in the art to configure the multilayer film to have a nitrogen (N) content of at least 1 atomic percent because incorporating nitrogen in the intermediate layer of the multilayer film provides the benefits of suppressing mixing of elements at the interfaces of the low and high refractive index layers of the multilayer film while also ensuring sufficient reflectivity of the multilayer film. Therefore, claims 2 and 12 would have been obvious at the time of the filing date of the present application
Regarding claims 3, 13 and 20, Mikami teaches [0070] the intermediate layer includes silicon (Si) and nitrogen (N), thereby the intermediate layer being configured to be composed of SiN. Therefore, claims 3 and 13 would have been obvious at the time of the filing date of the present application.
Claims 4, 5, 14, 15, 21 and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Mikami (US 2015/0160548 A1) in view of Mikami (US 2016/0109792 A1), herein referred to as Mikami ‘792.
Mikami does not appear to explicitly teach the limitations of claims 4, 5, 14, 15, 21 and 22. However, from the same field of technology, Mikami ‘792 recites the formation of a reflective mask blank and substrate for EUV lithography applications.
In view of claims 4, 14 and 21, Mikami ‘792 teaches [0070] employing ruthenium (Ru) as a material for a low refractive index layer that is then employed in a multilayer reflective film along with a silicon (Si) high refractive index layer.
In view of claims 5, 15 and 22, Mikami ‘792 teaches [0072 and 0074] the low and high refractive index layers may be stacked to form a multilayer film comprising 30 to 60 cycles (periods). Since the range of 30 to 60 cycles overlaps the range of 40 periods or less, a prima facie case of obviousness is established (MPEP Chapter 2144.05).
At the time of the filing date of the present application, it would have been obvious to one of ordinary skill in the art to modify the reflective layer-coated substrate, reflective mask blank and reflective mask taught by Mikami to include the teachings of Mikami ‘792 directed to substituting ruthenium (Ru) as a material for a low refractive index layer and the teachings of being able to forming a reflective multilayer film with less than 40 cycles in order to improve the reflectivity properties of the multilayer film. Therefore, claims 4, 5, 14, 15, 21 and 22 would have been obvious at the time of the filing date of the present application.
Claims 7, 17, 18, 24 and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Mikami (US 2015/0160548 A1) in view of Lin (US 2021/0397075 A1).
Mikami does not appear to explicitly teach the limitations of claims 7, 17, 18, 15, 24 and 25. However, from the same field of technology, Lin recites the formation of an EUV photomask for EUV lithography applications.
In view of claim 7, Lin teaches (Figures 2A, 2B and [0044]) forming a barrier layer (protection layer) on a multilayer reflective film of a EUV photomask blank. Lin further teaches the barrier layer can include silicon nitride (SiN).
In view of claims 17, 18, 24 and 25, Lin teaches [0040] an intermediate layer of the EUV photomask blank can include additive compounds such as carbon and oxygen. Although Lin does not explicitly teach the recited atomic percent ranges of carbon and oxygen, it would be obvious to one of ordinary skill in the art to modify the aforementioned atomic percent ranges because such modifications are known in the art.
At the time of the filing date of the present application, it would have been obvious to one of ordinary skill in the art to modify the reflective layer-coated substrate, reflective mask blank and reflective mask taught by Mikami to include the teachings of Lin directed to substituting silicon nitride as a material for a protective and the teachings of including carbon and oxygen in the intermediate layer in order to improve the reflectivity properties of the multilayer film. Therefore, claims 7, 17, 18, 24 and 25 would have been obvious at the time of the filing date of the present application.
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
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