DETAILED ACTION
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on January 7, 2026 has been entered.
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, 8-12, and 23 are rejected under 35 U.S.C. 103 as being unpatentable over Hauf et al. [US 2013/0176544] in view of Phillips et al. [US 2009/0122428].
For claim 1, Hauf teaches an optical system and associated method (a mirror in a microlithographic projection exposure apparatus, see [0075]), comprising:
at least one mirror (701, see Fig. 7) having an optical effective surface (701a) and a mirror substrate (701);
at least one cooling channel (751) configured to receive a cooling fluid for dissipating heat that is generated in the mirror substrate as a thermal load due to absorption of electromagnetic radiation incident from a light source on the optical effective surface (see [0076]-[0078] and [0086]);
a heater (760a-762a) arranged to heat the mirror in a spatially variable manner (selectively actuatable array, see [0085]),
a controller (regulating device, see [0070], [0076]-[0077], and [0086]) configured to adjust a temperature and/or a flow rate of the cooling fluid in accordance with either a measured quantity that characterizes the thermal load in the mirror substrate (regulating procedure to non-homogenous heat inputs in the mirror 701 by a corresponding variation in the heat or infrared radiation emitted by the low-temperature radiating mechanisms 760, 761, see [0086]) or an estimated thermal load determined for the mirror substrate for a given power of the light source, and configured to control the heater to differently heat two or more spatial regions of the optical effective surface to locally deform the optical effective surface mirror (heating the optically effective surface 701a, see [0083]) and simultaneously control the cooling channel to globally cool the mirror substrate (operated simultaneously, see [0088]).
Hauf fails to teach a mirror substrate (701) with at least one cooling channel formed within the mirror substrate material of the mirror substrate configured to receive a cooling fluid that flow within the mirror substrate material.
Phillips teaches an optical system (see Figs. 2(A), 2(B), 2(D), and 21), comprising: at least one mirror (30) having an optical effective surface (36) and a mirror substrate (body of the mirror) with at least one cooling channel (38) formed within the mirror substrate material of the mirror substrate (conduits are defined by the mirror body, see [0078]-[0082]) configured to receive a cooling fluid that flow within the mirror substrate material for dissipating heat that is generated in the mirror substrate as a thermal load due to absorption of electromagnetic radiation incident from a light source on the optical effective surface (liquid coolant is circulated through the conduits to remove heat caused by radiant energy, see [0077]), a controller comprises a feedback control unit that controls the temperature and/or the flow rate of the cooling fluid (maintained at a desired temperature using a feedback-controlled temperature-regulating device is circulated desirably at a controlled flow rate, see [0077]).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to provide the cooling channels and control as taught by Phillips in the cooling arrangement as taught by Hauf, because the cooling channels of Phillips allow for directly cooling the mirror substrate at desired temperature to counter act undesired heating of the mirror.
For claim 8, Hauf teaches an average zero-crossing-temperature of the mirror substrate material, at which a coefficient of thermal expansion of the mirror substrate material has a zero crossing in temperature dependence, is substantially equal to a manufacturing temperature at which the optical effective surface of the mirror has been shaped (zero crossing temperature can be set by the material manufacturer according to the desired properties of the thermal design, typical values being between 22C and 40C, see [0071]).
For claims 9 and 10, Hauf teaches the optical system is designed for an operating wavelength of less than 30 nm (13.5 nm, see [0004]).
For claims 11 and 12, Hauf teaches a microlithographic optical system comprising an illumination device and a projection lens, wherein at least one of the illumination device and the projection lens comprises the optical system (see [0021]).
For claim 23, Hauf teaches the heater comprises a plurality of irradiation sources (light sources 760a, 761a, see Fig. 7) configured to irradiate the substrate via paths through the substrate that do not include the at least one cooling channel (channels 751). Phillips teaches the cooling channels are within the substrate.
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to offset the light path of the source relative to a cooling channel as taught by Hauf, when the cooling channels are provided within the substrate as taught by Phillips in order to reduce the likelihood of deforming the substrate at the cooling channels changing the cross sectional area of the channels and unintentionally altering the flow path, creating an undesired temperature distribution.
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Hauf in view of Phillips as applied to claim 1 above, and further in view of Gellrich et al. [US 2009/0135385].
For claim 2, Hauf fails to teach the controller comprises a feedforward control unit that controls the temperature and/or the flow rate of the cooling fluid based on a prior estimation of the thermal load determined for the mirror substrate for different values of the power of the light source.
Gellrich teaches a controller (111.1, see Fig. 2) comprises a feedforward control unit that controls the temperature control device including a flow rate controller (110.1, 112.1, 113.1, 114.1, 114.4, 114.5, and 119.1 control the temperature of lens 109, see [0050]-[0054], [0063]) based on a prior estimation of the thermal load determined for the optical element for different values of the power of the light source (parameter includes light power, see [0044], parameters previously captured, [0046], known relation between parameter and temperature gathered by simulation or empiric data provides estimation with behavior model, see [0065], [0074], and [0136]).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to provide the feedforward control as taught by Gellrich in the control of the temperature of the mirror as taught by Hauf, because applying a temperature behavior model based on variable parameters that influence the temperature of the mirror will allow for predicting and mitigating temperature induced errors during the imaging process to maintain accuracy and throughput.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Hauf in view of Phillips as applied to claim 1 above, and further in view of Miyajima [US 2005/0128446].
For claim 3, Hauf fails to explicitly describe the controller comprises a feedback control unit that controls the temperature and/or the flow rate of the cooling fluid based on a measurement of a quantity that characterizes the thermal load in the mirror substrate
Miyajima teaches the controller comprises a feedback control unit that controls the temperature and/or the flow rate of the cooling fluid based on a measurement of a quantity that characterizes the thermal load in the mirror substrate (temperature feedback control, see Fig. 4 and [0064]).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to provide the Feedback control using temperature measurement as taught by Miyajima in the temperature regulation as taught by Hauf in order to ensure the desired homogeneous heat load is provided to the mirror.
Claims 5, 6, and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Hauf in view of Phillips as applied to claim 1 above, and further in view of Baer et al. [US 2013/0141707].
For claims 5 and 6, Hauf fails to teach the light source has a power of at least 1 kW.
Baer teaches an EUV light source has a power of at least 1 kW (see [0078]).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to provide the power to the light source as taught by Baer as the exposure power of the EUV light source of Hauf in order to provide the required dose to meet desired resolution and maintain sufficient throughput.
For claim 22, Hauf fails to explicitly teach the heater comprises a plurality of electrode heaters arranged between the substrate and the optical effective surface or a plurality of irradiation sources arranged to direct radiation with a wavelength at which the substrate is substantially transparent.
Baer teaches the heater comprises a plurality of electrode heaters arranged between the substrate and the optical effective surface or a plurality of irradiation sources arranged to direct radiation with a wavelength at which the substrate is substantially transparent (IR transparent material with matrix of IR sources, see [0189]-[0191] and Fig. 13).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to provide the IR transparent material of the substrate as taught by Baer in the substrate as taught by Hauf in order to homogenize the temperature distribution in the mirror body as well as the mirror surface.
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Hauf in view of Phillips as applied to claim 1 above, and further in view of Kamiya et al. [JP H11-176730].
For claim 7, Hauf fails to explicitly teach the temperature of the cooling fluid is set to vary in steps of at least 0.1 K.
Kamiya teaches the temperature of the cooling fluid is set to vary in steps of at least 0.1 K (liquid temperature control controller 6a performs control such that the temperature of the temperature control fluid is lowered, for example, by about 0.01 ° C. to 0.05 ° C, see page 11 of the translation).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to provide the fluid temperature control interval as taught by Kamiya in the coolant as taught by Hauf in order to provide a precise desired temperature of the cooling fluid so that the mirror temperature can be controlled with better resolution.
Claims 13 and 16-18 are rejected under 35 U.S.C. 103 as being unpatentable over Phillips in view of Gellrich and Hauf.
For claims 13 and 16-18, Phillips teaches method for operating an optical system (see Figs. 2(A), 2(B), 2(D), and 21), wherein the optical system has at least one mirror (30) having an optical effective surface (36) and a mirror substrate (body of the mirror), comprising:
providing at least one cooling channel (38) in mirror substrate material of the mirror substrate (conduits are defined by the mirror body, see [0078]-[0082]);
flowing a cooling fluid in the mirror substrate material cooling channel (conduits are defined by the mirror body, see [0078]-[0082]) to dissipate heat generated in the mirror substrate as a thermal load due to absorption of electromagnetic radiation incident from a light source on the optical effective surface (liquid coolant is circulated through the conduits to remove heat caused by radiant energy, see [0077]); and
adjusting a temperature and/or a flow rate of the cooling fluid (maintained at a desired temperature using a feedback-controlled temperature-regulating device is circulated desirably at a controlled flow rate, see [0077]).
Phillips fails to teach adjusting a temperature and/or a flow rate of the cooling fluid in accordance with an estimated thermal load determined for the mirror substrate for a given power of the light source, wherein said adjustment of the temperature and/or the flow rate of the cooling fluid comprises a feedforward control based on a prior estimation of the thermal load determined for the mirror substrate for different values of the power of the light source, wherein the prior estimation of the thermal load determined for the mirror substrate for different values of the power of the light source is made based on calibration measurements, wherein the prior estimation of the thermal load determined for the mirror substrate for different values of the power of the light source is made based on a simulation.
Gellrich teaches adjusting a temperature and/or a flow rate of the cooling fluid in accordance with an estimated thermal load determined for the optical element for a given power of the light source (temperature of the lens 109 is established with actual light power, see [0044], [0066], [0075], and [0135]), wherein said adjustment of the temperature and/or the flow rate of the cooling fluid comprises a feedforward control (control the temperature of lens 109, see [0050]-[0054], [0063]) based on a prior estimation of the thermal load determined for the optical element for different values of the power of the light source (parameter includes light power, see [0044], parameters previously captured, [0046] , known relation between parameter and temperature gathered by simulation or empiric data provides estimation with behavior model, see [0065], [0074], and [0136]), wherein the prior estimation of the thermal load determined for the optical elements for different values of the power of the light source is made based on calibration measurements (parameters previously captured, [0046], known relation between parameter and temperature gathered by simulation or empiric data provides estimation, see [0065], [0074], and [0136]), wherein the prior estimation of the thermal load determined for the optical element for different values of the power of the light source is made based on a simulation (simulation, see [0136]).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to provide the feedforward control as taught by Gellrich in the control of the temperature of the mirror as taught by Phillips, because applying a temperature behavior model based on variable parameters that influence the temperature of the mirror will allow for predicting and mitigating temperature induced errors during the imaging process to maintain accuracy and throughput.
Phillips fails to teach providing a heater arranged to heat the mirror in a spatially variable manner; and simultaneously operating the heater to locally deform the optical effective surface.
Hauf teaches a heater arranged to heat the mirror in a spatially variable manner (760a-762a in a selectively actuatable array, see [0085] and Fig. 7); and cooling while simultaneously operating the heater to locally deform the optical effective surface (operated simultaneously, see [0088]).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to provide the heater and simultaneous control as taught by Hauf in the mirror arrangement as taught by Phillips in order to account for different illumination settings, adjusting the temperature of the mirror to a uniform temperature along the coolant flow path and correcting for temporal mirror temperature inconsistencies that may occur during step and repeat exposure processing thereby maintaining or increasing throughput.
Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Phillips in view of Gellrich and Hauf as applied to claim 13 above, and further in view of Miyajima.
For claim 19, Phillips fails to explicitly describe said adjustment of the temperature and/or the flow rate of the cooling fluid comprises a feedback control based on measurements of a quantity that characterizes the thermal load of the mirror substrate during operation of the optical system.
Miyajima teaches said adjustment of the temperature and/or the flow rate of the cooling fluid comprises a feedback control based on measurements of a quantity that characterizes the thermal load of the mirror substrate during operation of the optical system (temperature feedback control, see Fig. 4 and [0064]).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to provide the feedback control using temperature measurement as taught by Miyajima in the temperature regulation as taught by Phillips in order to provide control that ensures that the mirror has reached a desired temperature relative to the temperature of the coolant to maintain desired mirror shape.
Claims 14 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Phillips in view of Gellrich and Hauf as applied to claim 13 above, and further in view of Baer.
For claims 14 and 15, Phillips fails to teach an average zero-crossing-temperature of the mirror substrate material, at which a coefficient of thermal expansion of the mirror substrate material has a zero crossing in temperature dependence, is substantially equal to a manufacturing temperature at which the optical effective surface of the mirror has been shaped, wherein said adjustment is made to maintain an average mirror temperature in a predefined temperature band, wherein a zero-crossing-temperature of the mirror substrate material, at which a coefficient of thermal expansion has a zero crossing in temperature dependence, is within the predefined temperature band.
Baer teaches teach an average zero-crossing-temperature of the mirror substrate material, at which a coefficient of thermal expansion of the mirror substrate material has a zero crossing in temperature dependence, is substantially equal to a manufacturing temperature at which the optical effective surface of the mirror has been shaped (heated to zero cross temperature to maintain shape, see [0198]), wherein said adjustment is made to maintain an average mirror temperature in a predefined temperature band (heated to keep mirror temperature above the lower bound, see [0197]-[0198]) wherein a zero-crossing-temperature of the mirror substrate material, at which a coefficient of thermal expansion has a zero crossing in temperature dependence, is within the predefined temperature band (temperature controlled within a small range at the zero cross temperature, see [0090], [0091], [0150], and [0179]).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to provide a mirror material and operate a heater to maintain the mirror material shape at desired temperature dependent on the zero crossing temperature of the material as taught by Baer in the control of the mirror temperature as taught by Phillips in order to more accurately control minimal temperature fluctuations of the mirror body and minimize the thermally induced optical aberrations.
Claim 20 is rejected under 35 U.S.C. 103 as being unpatentable over Phillips in view of Gellrich and Hauf as applied to claim 13 above, and further in view of Tsuji et al. [US 2005/0140959].
For claim 20, Phillips fails to teach the adjustment of the temperature and/or the flow rate of the cooling fluid comprises intervention of said feedback control in time intervals of less than 120 seconds.
Tsuji teaches temperature adjustment intervention of said feedback control should be short to reduce time wastage (shortened time wastage using PID controller optimized with FF controller, see [0103]-[0120]).
There is no evidence showing the criticality of the claimed control time interval.
The control time interval determines how quickly a controller can remedy out of band operation conditions. Accordingly, control time interval is a result effective parameter.
According to well established patent law precedent (see, for example, M.P.E.P. §2144.05) it would have been obvious to one of ordinary skill in the art at prior to the effective filing date of the claimed invention to determine (for example by routine experimentation) the optimum control time interval to maintain a temperature of a lithographic element within normal operating condition to maintain accuracy and throughput.
Response to Arguments
Applicant’s arguments with respect to claims 1 and 13 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument. Phillips is now relied upon to teach the salient features of the claims.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Hofstra et al. [US 2021/0165336] teaches in Fig. 3f and Sogard [US 2005/0099611] teaches in Figs. 4 and 12-16 a system for heating a backside of a mirror with cooling channels within the mirror.
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/Steven H Whitesell/Primary Examiner, Art Unit 1759