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 .
Prosecution Status
This Office Action is non-final rejection since the Examiner has changed the art and advanced new arguments.
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 1-20 are rejected under 35 U.S.C. 103 as being unpatentable over Schwab et al (US 2018/0074303 A1).
With respect to claims 1 and 17-20, Schwab discloses an imaging EUV optical unit configured to image an object field into an image field. In particular, Schwab discloses a projection exposure apparatus including a projection optical unit having a plurality of mirrors arranged along an imaging beam path from the object field to the image field. Schwab further discloses use of EUV imaging radiation having a wavelength of 13.5 nm (see figure 1 and associated description of the projection apparatus and projection optical unit; paragraph [0053]). Schwab further expressly distinguishes between normal incident mirrors (NI) and grazing incident mirrors (GI). In the embodiment of the projection optical unit (30) according to figures 21-25, Schwab teaches ten mirrors M1-M10, including three NI mirrors (M1; M9; M10) and seven GI mirrors (M2-M8). Thus, Schwab discloses substantially all limitations of the instant claims. Schwab further expressly teaches that the projection optical unit (30) has an overall transmission of 9.88% (see table 5 for figure 23). Schwab therefore differs from the claims, if at all, in that Schwab expressly reports an overall transmission of 9.88% whereas the claims require a total transmission of more than 10%. It would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention to optimize the reflectivity and associated optical parameters of one or more of the mirrors of Schwab so as to increase the overall transmission from the expressly disclose 9.88% to greater than 10% for the purpose of improving the efficiency of the projection exposure apparatus. Increasing the overall transmission from 9.88% to slightly greater than 10% requires only a minor improvement in the cumulative reflectivity of the mirror train and would have been a predictable result of routine optimization directed toward reducing optical losses and increasing the amount of usable EUV radiation reaching the image field and improving the quality of the printed images onto the substrate.
As to claim 2, Schwab expressly discloses the embodiment of figures 23-25 that the last two mirrors in the imaging beam path are mirrors M9 and M10 and that both M9 and M10 are NI mirrors.
As to claim 3, it would have been obvious to a skilled artisan to select the imaging unit (30) with exactly two NI mirrors since the claimed selection represents no more than the predictable selection of one of the alternative mirror configuration expressly taught by Schwab.
As to claims 4-5, 10-15, Schwab teaches multiple alternative EUV projection arrangements having different numbers of NI and GI mirrors. It would have been obvious to one of ordinary skill to select among the expressly disclosed mirror number arrangements of Schwab according to the desired numerical aperture, aberration correction, package size, object image offset, working distance and optical transmission, as recited in the mentioned claims for the purpose of improving the quality of the projection exposure apparatus.
As to claims 6 and 16, Schwab teaches folded projection optical arrangements in which imaging beam path sections extend between successive mirrors and through or past regions of other optical components, including arrangements employing passage openings and intermediate-image regions. The various folded beam-path conjurations disclosed by Schwab demonstrate that the relative positioning of successive imaging beam-path sections is an optical-layout parameter selected in accordance with packaging, intermediate-image placement, obscuration and aberration requirements. It would have been obvious to one of ordinary skill in the art before the effective filling date of the claimed invention, when arranging the folded imaging beam path of Schwab, to permit two imaging beam path sections to cross where appropriate in order to obtain the desired compact optical packaging and imaging geometry, such crossing representing a predictable geometrical arrangement of the known folded beam path rather than a change in the principle of operation of the EUV projection optical unit.
Response to Arguments
Applicant’s arguments filed July 17, 2026 have been carefully reviewed but have been traversed in view of a new ground of rejection as set forth above.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to HUNG HENRY NGUYEN whose telephone number is (571)272-2124. The examiner can normally be reached Monday-Friday 7:00AM-4:30PM.
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HUNG HENRY NGUYEN
Primary Examiner
Art Unit 2882
Hvn
8/22/26
/HUNG V NGUYEN/Primary Examiner, Art Unit 2882
Prosecution Insights