DETAILED ACTION
Claim Objections
Applicant is advised that should claim 30 be found allowable, claim 8 will be objected to under 37 CFR 1.75 as being a substantial duplicate thereof. When two claims in an application are duplicates or else are so close in content that they both cover the same thing, despite a slight difference in wording, it is proper after allowing one claim to object to the other as being a substantial duplicate of the allowed claim. See MPEP § 608.01(m).
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.
Claims 1-11 and 29-37 are rejected under 35 U.S.C. 103 as being unpatentable over Kaller et al. [US 2013/0120863] in view of Eva [DE 10 2017 221 388] and Phillips et al. [US 2009/0122428].
For claims 1, 5, 6, 11, 30, and 32-37, Kaller teaches an apparatus, comprising: an illumination optical unit; and a projection optical unit, wherein the apparatus is a microlithographic projection exposure apparatus, and a member selected from the group consisting of the illumination optical unit (illumination systems, see [0009]). and the projection optical unit (projection system, see [0009]) comprises a mirror (lithographic apparatus, see [0009]); the mirror, comprising:
a first mirror part (one of the material sections of the substate formed by rectangle R1-R3, see Fig. 12a-12b); and
a second mirror part (another of one of the adjacent material sections of the substate formed by rectangle R1-R2, see Fig. 12a-12b), wherein:
the first and second mirror parts comprises a material with a very low coefficient of thermal expansion (a titanium-doped quartz glass blank in the form of a boule, see [0084]);
the second first mirror parts are permanently connected to one another in a region of a first connecting surface of the first mirror part and a second connecting surface of the second mirror part (material sections cut and connected to form substrate, see [0087] and Figs. 12a-12b);
the first mirror part has a first mean value of a zero crossing temperature in a first volume region extending up to a distance of 10 mm into the first mirror part from the first connecting surface (average zero crossing temperature along surfaces of sections R1-R3, where scale is given in inches, the thickness of each section is approximately 50 mm, see [0084]-[0085] and Figs. 10, and 12a-12b);
the second mirror part has a second mean value of the zero crossing temperature in a second volume region extending up to a distance of 10 mm into the second mirror part from the second connecting surface (average zero crossing temperature along surfaces of sections R1-R3, where scale is given in inches, the thickness of each section is approximately 50 mm, see [0084]-[0085] and Figs. 10, and 12a-12b);
the first and second mirror parts comprise fault zones within which at least one material parameter deviates from a specified value by more than a minimum deviation (the distribution of the zero-crossing temperature in the boule is periodic with a period of about 4-5 inches, see [0084] and [0085]); and
the fault zones of the first mirror part adjoin fault zones of the second mirror part with at least 50% of the overall area taken up by them at the location of the first connecting surface (section cut at approximately 5-6 inch steps, see Fig. 12a)
Kaller fails to teach that the first mean value of the zero crossing temperature is within 1 Kelvin from the second mean value of the zero crossing temperature.
Eva teaches the first mean value of the zero crossing temperature is within 1 Kelvin from the second mean value of the zero crossing temperature (the zero crossing temperature in the substrate spatially varies by not more than 1.0 K (in absolute value), to a distance of 3 cm from the surface, see page 9 and Fig. 4).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to limit variation around the average zero-crossing temperature over a 30 mm range in the mirror as taught by Eva in the substrate section arrangement having a 20 mm range as taught by Kaller in order to minimize temperature-induced deformations of the substrate that translate to the surface of the mirror.
Kaller fails to teach the first connecting surface and the second connecting surface are curved, wherein a curvature of the first curved connecting surface is the same as a curvature of the second curved connecting surface.
Phillips teaches the first connecting surface and the second connecting surface are curved (surfaces of 32a and 32b, see Fig. 2(D) and [0078]), wherein a curvature of the first curved connecting surface is the same as a curvature of the second curved connecting surface (matching radius of curvature, see Fig. 2D).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to introduce the curved surfaces in the bonding of two elements of mirror substrate as taught by Phillips in the manufacture of a mirror blank as taught by Kaller, because the curved surfaces allow for introducing channels between the two surface that are equidistant from the optical surface of the mirror to provide uniform cooling while providing the desired optical power.
For claims 2, 8, and 29, Kaller teaches the blank comprises a material selected from the group consisting of a fused silica, a titanium-doped fused silica (a titanium-doped quartz glass blank in the form of a boule, see [0084]), and a glass ceramic.
For claims 3 and 9, Kaller teaches a unit, comprising: the mirror, wherein the unit is an illumination optical unit (illumination systems, see [0009]).
For claims 4 and 10, Kaller teaches a unit, comprising: the mirror, wherein the unit is a microlithographic projection optical unit (projection system, see [0009]).
For claims 7 and 31, Kaller teaches the fault zones continue from the first mirror part into the second mirror part (shift of location where sections R1-R3 are cut align with the period length, see [0084] and [0085] and Figs. 10 and 12a-12b).
Response to Arguments
Applicant's arguments filed January 23, 2026 have been fully considered but they are not persuasive.
The Applicant argues on pages 6 and 7 of the Remarks, regarding claim 1, that Kaller teaches the contacting surface of the mirror substrate are planar and not curved in the embodiment described with respect to Fig. 12A and 12B, and that a curved contacting surface would be contrary to the arrangement of the periodic arrangement of the zero crossing temperature relative to the surface of the substrate.
The Examiner respectfully disagrees. In the combination with Phillips, a curved surface would still allow for optimizing the period length along the substrate surface such that the zero-crossing distribution is longer than in the direction normal to the surface for the cut-out substrate because the curved surface would still have the periodic arrangement either along a secant or some other function that describes the mirror surface. Further, by using curved surfaces, the combination provides a desired optical power and cooling channels at optimal locations within the optical element, reducing the need for machining the surface after joining which may introduce undesired deformation.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Steven H Whitesell whose telephone number is (571)270-3942. The examiner can normally be reached Mon - Fri 9:00 AM - 5:30 PM (MST).
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Duane Smith can be reached at 571-272-1166. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/Steven H Whitesell/Primary Examiner, Art Unit 1759