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
Acknowledgment is made of applicant's claim for foreign priority based on an application filed in Korea on Jan. 2, 2024. It is noted, however, that applicant has not filed a certified copy of the Korean application as required by 37 CFR 1.55.
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.
Claim(s) 1, 3, 4 and 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hayashi et al. (Hayashi) (2011/0104595) in view of Franke et al. (Franke) (2022/0236645) and Conley et al. (Conley) (2024/0045341).
Regarding claim 1, Hayashi discloses a method of configuring an extreme ultraviolet (EUV) illumination system, the method comprising: measuring a phase of an EUV mask (para 0011 and 0014, measuring the phase of EUV reflected light from a surface of absorber layer and the phase of EUV reflected light from a surface of reflective layer). Hayashi discloses improving contrast by phase shifting (para 0008, 0011). However, Hayashi does not disclose correcting a wavefront based on the phase of the EUV mask; optimizing a cost function; and configuring an EUV illumination system with a combination of EUV light sources based on the optimized cost function. Franke discloses mask 3D effect of M3D which causes phase shifting and modulation (para 0010, 0043, 0044). Franke discloses correcting wavefront based on the phase of the mask (para 0010, 0011, 0038, 0040, 0062). Conley discloses optimizing a cost function (para 0076, 0092); and configuring an EUV illumination system with a combination of EUV light sources based on the optimized cost function (para 0092, illumination optimization to minimize or maximize the cost function). Therefore, it would have been obvious to one of ordinary skill in the art to improve contrast and pattern shifting by modifying wavefront based on the phase of EUV mask as taught by Franke and to optimize a cost function and configure an EUV illumination system based on a combination of EUV light sources based on the optimized cost function as taught by Conley by adjust multiple variables to improve imaging while balancing the physical mask constraints.
Regarding claim 3, Hayashi discloses wherein the EUV mask (Fig. 1, 9) comprises a multi-layer (3) with a first reflectivity (para 0035) and an absorber layer (4) with second reflectivity that is lower than the first reflectivity (para 0035).
Regarding claim 4, Hayashi does not disclose wherein the wavefront is corrected based on a 6th term of Zernike polynomials. Franke discloses wherein the wavefront is corrected based on a 6th term of Zernike polynomials (para 0038-0040). Therefore, it would have been obvious to one of ordinary skill in the art to correct wavefront based on a 6th term of Zernike polynomials for the reasons stated above.
Regarding claim 17, Hayashi discloses an extreme ultraviolet (EUV) exposure method comprising: preparing an EUV mask (Fig. 1, 9, para 0011, 0032-0035); configuring an EUV illumination system corresponding to the EUV mask (inherent to EUV lithography, abstract, para 0001); and performing EUV exposure on a wafer using the EUV illumination system (inherent to EUV lithography); wherein the configuring of the EUV illumination system comprises: measuring a phase of the EUV mask (para 0011 and 0014, measuring the phase of EUV reflected light from a surface of absorber layer and the phase of EUV reflected light from a surface of reflective layer). Hayashi discloses improving contrast by phase shifting (para 0008, 0011). However, Hayashi does not disclose performing a first correction of a wavefront based on the phase of the EUV mask; optimizing a cost function; and configuring the EUV illumination system with a combination of EUV light sources based on the optimized cost function. Franke discloses correcting wavefront based on the phase of the mask (para 0010, 0011, 0038, 0040, 0062). Conley discloses optimizing a cost function (para 0076, 0092); and configuring an EUV illumination system with a combination of EUV light sources based on the optimized cost function (para 0092, illumination optimization to minimize or maximize the cost function). Therefore, it would have been obvious to one of ordinary skill in the art to improve contrast and pattern shifting by modifying wavefront based on the phase of EUV mask as taught by Franke and to optimize a cost function and configure an EUV illumination system based on a combination of EUV light sources based on the optimized cost function as taught by Conley by adjust multiple variables to improve imaging while balancing the physical mask constraints.
Claim(s) 2 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hayashi et al. (Hayashi) in view of Franke et al. and Conley et al. as applied to claim 1 above, and further in view of Park et al. (Park) (2021/0293701).
Regarding claim 2, the further difference between the claimed invention and the modified Hayashi is wherein the phase of the EUV mask is measured based on an intensity of light reflected from the EUV mask. Park discloses measuring a phase of EUV mask based on intensity of light reflected from EUV mask (abstract, para 0036). Therefore, it would have been obvious to one of ordinary skill in the art to measure the phase of the EUV mask based on an intensity of reflected light for fabrication of EUV mask as taught by Park.
Allowable Subject Matter
Claims 8-16 are allowed.
Claims 5-7 and 18-20 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Regarding claim 8, none of the prior art of record teaches or discloses performing a first correction of a wavefront based on the contrast loss; optimizing a cost function; performing a second correction of the wavefront; and configuring an EUV illumination system with a combination of EUV light sources based on the optimized cost function in combination with the rest of the limitations.
Regarding claim 5, none of the prior art of record teaches or discloses wherein the cost function is determined based on an edge placement error (EPE), illumination efficiency, and rotational symmetry in combination with the rest of the limitations.
Regarding claim 18, none of the prior art of record teaches or discloses wherein the configuring of the EUV illumination system further comprises: determining a contrast loss based on the phase of the EUV mask; and performing a second correction of the wavefront in combination with the rest of the limitations.
Franke et al. discloses modifying wavefront to correct pattern shift, which is related to contrast loss, but Franke does not disclose a first wavefront correction, optimizing a cost function and performing a second correction of the wavefront.
Conley et al. discloses cost function determined based on an edge placement error (para 0112). However, Conley et al. does not disclose cost function based on EPE, illumination efficiency and rotational symmetry.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Blumrich et al. (2018/0164207) discloses an EUV mask (Fig. 4) comprising reflecting multilayer (440) and absorption layer (460) and determining phase (para 0034). However, Blumrich et al. does not disclose correcting wavefront based on the phase and optimizing a cost function.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to PETER B KIM whose telephone number is (571)272-2120. The examiner can normally be reached M-F 8:00 AM - 4:00 PM.
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/PETER B KIM/Primary Examiner, Art Unit 2882 May 30, 2026
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