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. 18/360853 by Lee et al.
Claims 1-20 are currently pending and have been fully considered.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim 1-3 and 5-8 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Ikebe et al. (US 2019/0384157 A1), herein referred to as Ikebe.
Regarding claim 1, Ikebe teaches ([0035, 0037, 0083, 0088] and Figure 2(d) shown below) a reflective mask 200 having a phase shift pattern (attenuated phase-shifting mask (APSM)) comprising a substrate 1 having a first side and a second side opposite to the first side; a multilayer reflective film (multi-layer structure) 2 over the first side of the substrate; a protective layer (capping layer) over the multilayer reflective film; and an absorber pattern (absorber layer) 4a over a portion of the protective layer, which is formed from a reflective mask blank comprising the layers discussed above, an absorber film 4 and resist layer 11 (Figures 2(a-c) and [0155-0156]).
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Ikebe further teaches [0172-0174] the absorber film comprises a CoTa film (first material and a second material different from the first material), a thickness of the absorber film is 40.4 nm (between approximately 30 nm and approximately 65 nm), the refractive index of the CoTa film is 0.936 (a refractive index (n) of the absorber layer is between approximately 0.860 and approximately 0.945), and the extinction coefficient of the CoTa film is about 0.059 (an extinction coefficient (k) of the absorber layer is between approximately 0.015 and approximately 0.070).
Regarding claim 2, Ikebe teaches [0065] the multilayer reflective film comprises alternately laminated molybdenum (Mo) and silicon (Si) films.
Regarding claim 3, Ikebe teaches [0068] the protective film comprises materials such as ruthenium (Ru), molybdenum (Mo) or zirconium (Zr).
Regarding claims 5 and 6, Ikebe teaches [0105] a back side conductive film (coating layer) 5 is disposed on the side of the second main surface of substrate 1. The back side conductive film may comprise a chromium containing compound such as chromium nitride (CrN).
Regarding claim 7, Ikebe teaches [0076-0080] the absorber film may comprise an alloy of a first material and a second material.
Regarding claim 8, Ikebe teaches [0074 and 0087] the absorber film may be configured to be a two-layer structure (bi-layer structure) wherein the upper layer (first layer) can include the first material and the upper layer (second layer) can include the second material.
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.
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Ikebe et al. (US 2019/0384157 A1), herein referred to as Ikebe.
Regarding claim 4, Ikebe teaches [0071] the protective film (capping layer) may be configured to have a thickness of 1.5 nm to 6 nm. The range of thicknesses taught by Ikebe overlaps the claimed range of approximately 3 nm to approximately 5 nm.
MPEP Chapter 2144.05 Section I states “In the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)”. Since the claimed range of the capping layer thicknesses lies inside the range of protective film thicknesses taught by Ikebe, a prima facie case of obviousness exists and claim 4 is considered to be obvious in view of Ikebe.
Claims 18-20 are rejected under 35 U.S.C. 103 as being unpatentable over Ikebe (US 2022/0107557 A1).
Regarding claims 18 and 19, Ikebe teaches [0179-0181] a method of manufacturing a semiconductor device using a reflective mask (photomask) and a EUV light source (EUV lithography method). The reflective mask comprises [0064 and 0097-0099] a substrate, a multilayer reflective film (multi-layer structure) formed on the substrate, a protective film (capping layer) formed on the multilayer reflective film and a layered film (absorber layer) functioning as a phase shift film. Ikebe further teaches [0107-0110] the layered film is configured to comprise a first material and a second material that differs in composition from the first material.
With further regard to claim 19, Ikebe teaches (Figure 4 and [0182-0184]) a pattern transfer device (EUV lithography system) that receives a resist covered semiconductor substrate (resist coated wafer), directs light generated by a laser plasma X-ray source to a reflective mask and subsequently, EUV light reflected from the reflected mask is directed to the resist covered semiconductor substrate to form a pattern in the resist. Ikebe further teaches the resist layer is developed after being exposed to the EUV light and then an etching process is performed on the semiconductor substrate with the patterned resist functioning as an etching mask (performing a fabrication operation on the wafer through the patterned photoresist layer).
Ikebe does not appear to explicitly teach the limitation in claims 18 and 19 directed to “a first reflected light is obtained from the capping layer and a second reflected light is obtained from the absorber layer during the exposure, and the first reflected light and the second reflected light have a phase shift between proximately 1.1π and approximately 1.3π”.
However, Ikebe teaches [0104-0105] EUV light reflected by the multilayer reflective film with the protective film (capping layer) and EUV light reflected by the layered film (absorber layer) produces a phase difference of 160 to 200 degrees. In view of Applicant’s claimed range of phase shift (1.1π x 180/ π = 198 degrees to 1.3π x 180/ π = 234 degrees), the phase shift difference achieved by Ikebe overlaps Applicant’s claimed range.
MPEP Chapter 2144.05 Section I states “In the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)”. Since the claimed range of the phase shift overlaps the range of phase difference taught by Ikebe, a prima facie case of obviousness exists and claims 18 and 19 are considered to be obvious in view of Ikebe.
Regarding claim 20, Ikebe teaches [0192-0195] the layered film may be configured to have a total thickness of 61.8 nm (first layer thickness of 57.3 nm + second layer thickness of 4.5 nm), which falls within the claimed thickness range of approximately 30 to approximately 65 nm.
Claims 16 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Ikebe et al. (US 2019/0384157 A1), herein referred to as Ikebe, in view of Ikebe (US 2022/0107557 A1), herein referred to as Ikebe ‘557.
Ikebe teaches a reflective mask that satisfies the limitations of claim 1 as discussed above. Ikebe does not appear to explicitly teach the limitations of claims 16 and 17. However, from the same field of technology, Ikebe ‘557 recites the formation of a reflective mask for EUV lithography applications.
In view of claim 16, Ikebe ’557 teaches [0104-0105] the relative reflectance (ratio of reflectivity) of the layered film to the relative reflectance of the multilayer reflective film including the protective film is from 3 percent to 40 percent.
MPEP Chapter 2144.05 Section I states “In the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)”. Since the claimed ratios of reflectivity fall within the reflectivity range taught by Ikebe ‘557, a prima facie case of obviousness exists and claim 16 is considered to be obvious in view of Ikebe ‘557.
In view of claim 17, Ikebe ‘557 teaches [0104-0105] EUV light reflected by the multilayer reflective film with the protective film (capping layer) and EUV light reflected by the layered film (absorber layer) produces a phase difference of 160 to 200 degrees. In view of Applicant’s claimed range of phase shift (1.1π x 180/ π = 198 degrees to 1.3π x 180/ π = 234 degrees), the phase shift difference achieved by Ikebe ‘557 overlaps Applicant’s claimed range.
MPEP Chapter 2144.05 Section I states “In the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)”. Since the claimed range of the phase shift overlaps the range of phase difference taught by Ikebe ‘557, a prima facie case of obviousness exists and claim 17 is considered to be obvious in view of Ikebe ‘557.
Claims 9-14 are rejected under 35 U.S.C. 103 as being unpatentable over Ikebe et al. (US 2019/0384157 A1), herein referred to as Ikebe, in view of Kim et al. (US 2021/0318608 A1), herein referred to as Kim.
Ikebe teaches a reflective mask that satisfies the limitations of claim 1 as discussed above. Ikebe does not appear to explicitly teach the limitations of claims 9-14. However, from the same field of technology, Kim recites the formation of a reflective mask for EUV lithography applications.
In view of claims 9-11, Kim teaches (Claims 1 and 12, [0033, 0034,0053, 0054]) a phase shift mask comprising a phase shift layer disposed on the reflective mask wherein the phase shift layer is configured to have a stacked structure that may include alternately stacked upper absorption (high refractive index) layers and lower absorption (low refractive index) layers. The lower absorption layer may include ruthenium (Ru) and the upper absorption layer may include tantalum nitride (TaN). Therefore, 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 reflective mask taught by Ikebe to include the phase shift layer configuration taught by Kim in order to manufacture a phase shifting reflective mask with improved capability to form high resolution patterns when used in an EUV lithography process.
In view of claims 12-14, it would have been obvious to one of ordinary skill in the art to modify the reflective mask taught by Ikebe to include the phase shift layer configuration taught by Kim and further substitute known phase shifting materials, as recited in claims 12-14, because one of ordinary skill in the art would have a reasonable expectation of success in using various phase shifting materials to optimize the phase shifting capability of the reflective mask.
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Ikebe et al. (US 2019/0384157 A1), herein referred to as Ikebe, in view of Oh (US 2010/0304277 A1).
Ikebe teaches a reflective mask that satisfies the limitations of claim 1 as discussed above. Ikebe does not appear to explicitly teach the limitations of claim 15. However, from the same field of technology, Oh recites the formation of a photomask for EUV lithography applications.
In view of claim 15, Oh teaches [0040] a photomask with an absorber pattern that is subjected to oxygen doping. The oxygen doping reduces reflectivity properties in the absorber pattern. Therefore, 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 reflective mask taught by Ikebe to include an absorber pattern with oxygen doping taught by Oh in order to manufacture a phase shifting reflective mask with improved capability to form high resolution patterns when used in an EUV lithography process.
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/STEWART A FRASER/Primary Examiner, Art Unit 1724