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 .
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 12/14/2023, 02/14/2024, 06/2/2025, and 08/22/2025 are being considered by the examiner.
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.
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.
Claim(s) 1,4, 5, and 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al (US 20160357099 A1)
Regarding Claim 1, 5, and 7 Kim teaches a mask for an extreme ultraviolet lithography process and a method of manufacturing such (Abstract). The mask comprises a substrate, a reflection layer comprising first and second material layers that are alternatingly and repeatedly stacked on the substrate, a capping layer on the reflection layer, and a phase shift layer and an absorber layer sequentially stacked on the capping layer. Sidewalls of the phase shift layer and the absorber layer may be oblique to a top surface of the capping layer.
Kim however does not explicitly disclose an experimental embodiment comprising the mask.
These limitations are met by the general disclosure of the reference.
The mask of Kim is more specifically disclosed from [0007] [0043] and [0043]-[0092], wherein, as per Fig 1, the mask comprises a substrate 100, a reflection layer 120R thereon, a capping layer 130 on the reflection layer 120R, a phase shift layer 140 on the capping layer 130, and an absorber layer 150 on the phase shift layer 140.
The reflection layer is formed by a plurality of layers 120U stacked on the substrate, wherein a series of first material layer 121 and a second material layer 122 are used to form the reflection layer, as described from [0052]-[0056].
The capping layer 130 is formed atop the reflection layer 120R so as to protect the reflection layer, and may be formed of a different material than the layers of the reflection layer 120R.
The phase shift layer 140 and absorber layer 150 are used to defined the absorption and reflection regions of the mask for an EUV lithographic process, wherein the regions defined by these layers are absorption regions and the areas not defined are reflective regions.
The sidewalls of the phase shift layer and absorber layer may be oblique to a top surface of the capping layer or reflection layer, wherein figs 2-3 depict angles relative to the vertical (perpendicular), and Figs 6 and 7 describe these angles between 68 degrees and 92 degrees and their effect on processing parameters (claim 5, where the range of angles overlaps the claimed range from 68 to ‘less than’ 90 degrees). The material of the absorber layer may be TaN, which has an absorption coefficient (extinction coefficient) 0.0436.
Also discussed by the reference is a method of forming/fabricating ([0011] and [0024]) the mask, wherein the provided substrate has the reflection layer formed atop the substrate, the capping layer is formed atop the reflection layer to protect it, and the phase shift and absorber layers are formed by forming these layers atop the capping layer, then successively etching them to define a pattern having sidewall geometries desired (also see [0050]-[0074]) (claim 7).
Kim ascribes improved process margin and yield to EUV lithography processes using the mask taught therein ([0073]).
A person having ordinary skill in the art would have found it obvious to arrive at the claimed invention prior to the effective filing date from the disclosure of the reference by using the materials and methods of etching to arrive at an EUV lithographic mask for use in improving lithographic processing.
Regarding Claim 4, Kim teaches a mask for an extreme ultraviolet lithography process and a method of manufacturing such (Abstract). The mask comprises a substrate, a reflection layer comprising first and second material layers that are alternatingly and repeatedly stacked on the substrate, a capping layer on the reflection layer, and a phase shift layer and an absorber layer sequentially stacked on the capping layer. Sidewalls of the phase shift layer and the absorber layer may be oblique to a top surface of the capping layer.
Kim however does not explicitly disclose an experimental embodiment comprising the mask.
These limitations are met by the general disclosure of the reference.
The sidewalls of the phase shift layer and absorber layer may be oblique to a top surface of the capping layer or reflection layer, wherein figs 2-3 depict angles relative to the vertical (perpendicular), and Figs 6 and 7 describe these angles between 68 degrees and 92 degrees and their effect on processing parameters. The material of the absorber layer may be TaN, which has an absorption coefficient (extinction coefficient) of 0.0436.
Figure 4 and [0028] describes the thickness of the absorber layer (height), where the thickness of the absorber layer may be 5nm or greater. A width is not defined, though as per figures 2 and 3, the width of the layer is generally presumed to be greater than the thickness/height of the layer. When w>h, the value of 2(h/w) as required by the claim is less than 2 because h/w will be less than 1.
The limitations of the claim state that the side wall angle must satisfy the relationship where the tangent of the angle is greater than twice the ratio of the height to width. The angle may range from 68 to 88, where the tangent of this range is 2.47 to 28.63. The tangents of all angles in the reference’s range are greater than 2 and as such meet the limitations of the claim.
Kim ascribes improved process margin and yield to EUV lithography processes using the mask taught therein ([0073]).
A person having ordinary skill in the art would have found it obvious to arrive at the claimed invention prior to the effective filing date from the disclosure of the reference by using the materials and methods of etching to arrive at an EUV lithographic mask for use in improving lithographic processing.
Claim(s) 2, 3, 6, and 8-17 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al (US 20160357099 A1) as applied to claim 1 above, and further in view of Komizo et al (WO 2020100632 A1, published 05/22/2020, US 20220011662 A1 used in lieu of translation).
Regarding Claim 2, 3, 6, 8, and 11-17, Kim teaches the limitations of the claims as discussed above regarding claim 1, including but not limited to where the angles of the sidewall in the absorption layer is are less than 90 degrees and between 65 and 90 degrees (claims 11-13), .
However, Kim does not teach the etching of the absorption layer with a chlorine or fluorine gas, or the optical density and thickness of the absorption layer, or that the material of the absorption layer comprises 50 at% or more of a tin, indium, tellurium and/or cobalt metal/oxide/oxynitride/nitride.
These limitations are met by Komizo.
Komizo discloses a reflective photomask blank and a reflective photomask made therefrom having irradiation resistance and good transfer performance (Abstract).
The reflective photomask blank is illustrated in Fig. 1 and described as having a substrate 1, a reflective layer 2 (claimed reflective part), and an absorption layer 4 (claimed low reflective part configured to absorb incident light) deposited on the reflective layer 2. The reflective layer 2 has a component multilayer reflective layer 2a and an intermediate layer 2b (such as a capping layer – [0087]). See [0027]-[0031]. Atop the capping layer is an absorption layer.
In the examples, at [0092]-[0098], chlorine-based gas etching is used to pattern the absorption layer as part of a photolithographic patterning process (claims 6, and 14-17).
The absorption layer 4 ([0037]-[0083] ) contains a first material selected from tin, indium, and tellurium, and a second material containing two or more materials selected from the group consisting of transition metals, bismuth, and silicon. The first material may be determined according to the value of an extinction coefficient for optimal lithographic processing is to be performed – for when tin is present, 17 at% or greater should be tin, for tellurium and indium this value should be 21 or greater or 17 at% or greater respectively. The second material should comprise between 20 and 50 at% of the material in the layer. The layer should contain oxygen, such as in an oxide of the first material or second material, preferably an oxide of the first material.
The thickness of the film of the absorption layer should be between 18nm and 45nm (0043]). The optical density (OD) of the absorption layer should be at least 1 ([0045) (claim 3, 8)
The first material should include materials having high extinction coefficients - higher than 0.041. See [0056]-[0068], where tin oxide and tantalum together are described as enabling a reduction in film thickness needed for a particular optical density due to the high extinction coefficient of the tin oxide material, and indium oxide films comprising tantalum are also discussed. The reference points out indium (In), tellurium (Te), and tin (Sn) oxides as preferable materials for use as the high extinction coefficient material.
The transition metals of the second material may be selected from tantalum, gold, osmium, hafnium, tungsten, platinum, rhenium, and zirconium, and the metals may be present singly or in combinations of two or more within the absorption layer (examiner’s emphasis where bolded). The amount of secondary material, including transition metals, incorporated into the absorption layer should range from 20 at% to 50 at% in total. The reference ascribes maintenance of the aggregate layer material’s extinction coefficient above 0.050 when the content of the transition metal material is present in this range, and ascribes improved EUV resistance to inclusion in this amount ([0074]-[0087].
The reference teaches that the absorption layer may comprise, for example – one of indium oxide, tellurium oxide, or tin oxide in an amount ranging from 17 at% or greater (22% or greater for tellurium oxide), and the second material comprising tungsten and tantalum in a total amount ranging from 20 at% to 50 at%. As such, the reference contemplates the inclusion of SnO2/TeO2/InO2 in 17-80at% (or 22-80at% for TeO2) – overlapping the claimed range regarding the high extinction coefficient material of “50 at% or more” (interpreted as 50-100 at%) at 50 at% to 80 at%
A person having ordinary skill in the art would have found it obvious to arrive at the claimed invention prior to the filing date from the disclosure of the reference – incorporating the taught compositional materials of Komizo into the absorber layer of Kim to improved optical density and reduced thickness required to achieve such by the inclusion of SnO2/InO2/TeO2.
Regarding Claim 9 and 10, Kim teaches a mask for an extreme ultraviolet lithography process and a method of manufacturing such (Abstract). The mask comprises a substrate, a reflection layer comprising first and second material layers that are alternatingly and repeatedly stacked on the substrate, a capping layer on the reflection layer, and a phase shift layer and an absorber layer sequentially stacked on the capping layer. Sidewalls of the phase shift layer and the absorber layer may be oblique to a top surface of the capping layer.
Kim however does not explicitly disclose an experimental embodiment comprising the mask.
These limitations are met by the general disclosure of the reference.
The sidewalls of the phase shift layer and absorber layer may be oblique to a top surface of the capping layer or reflection layer, wherein figs 2-3 depict angles relative to the vertical (perpendicular), and Figs 6 and 7 describe these angles between 68 degrees and 92 degrees and their effect on processing parameters. The material of the absorber layer may be TaN, which has an absorption coefficient (extinction coefficient) of 0.0436.
Figure 4 and [0028] describes the thickness of the absorber layer (height), where the thickness of the absorber layer may be 5nm or greater. A width is not defined, though as per figures 2 and 3, the width of the layer is generally presumed to be greater than the thickness/height of the layer. When w>h, the value of 2(h/w) as required by the claim is less than 2 because h/w will be less than 1.
The limitations of the claim state that the side wall angle must satisfy the relationship where the tangent of the angle is greater than twice the ratio of the height to width. The angle may range from 68 to 88, where the tangent of this range is 2.47 to 28.63. The tangents of all angles in the reference’s range are greater than 2 and as such meet the limitations of the claims.
Kim ascribes improved process margin and yield to EUV lithography processes using the mask taught therein ([0073]).
A person having ordinary skill in the art would have found it obvious to arrive at the claimed invention prior to the effective filing date from the disclosure of the reference by using the materials and methods of etching to arrive at an EUV lithographic mask for use in improving lithographic processing.
Conclusion
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/A.P.T./Examiner, Art Unit 1737
/SALLY A MERKLING/SPE, Art Unit 1738
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