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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 February 17, 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 19-28, 34, 36-38, 43, 45-49 and 51 are rejected under 35 U.S.C. 103 as being unpatentable over Sandstrom et al. [US 2005/0083983] in view of Algots et al. [US 2006/0114957].
For claims 19 and 23, Sandstrom teaches a photolithography system (lithography stepper/scanner, see [0060]) comprising:
a pulsed light source (20, see Fig. 1) comprising a spectral feature selection module (100 and LNM 26) positioned at a side of a gas discharge chamber (22), the spectral feature selection module comprising a plurality of prisms forming a beam expander (variably refractive optical elements 100 or 100' with multi prism expander, see Figs. 2-5 and [0056]-[0060]) arranged relative to a grating (variably refractive optical elements inserted in the optical path between the laser and the grating in existing line narrowing modules, see [0054] and [0087]); and
a communications interface (control signal interface between controller scanner 280 and controller 290 and LNM 26, see Figs. 16 and 17) coupled to a pulsed light source (LNM 26) and configured to receive a plurality of input signals (signals from scanner 280 and controller 290, see Figs. 16, 17 and [0085]-[0088]);
a processor (controller 290) coupled to the communications interface,
wherein: the input signals comprise indications of a timing of pulses of light to be emitted by the pulsed light source (signals indicative of pulse timing and repetition rate, see [0085]-[0088]) during a single exposure pass (both wavelengths exposed during a single exposure pass, λ1 during exposure via strips 310-318 and λ2 during exposure via strips 322-330, see Fig. 18 and [0069]-[0070]); and
the input signals comprise an indication of a spectral separation between a first plurality of pulses among the pulses of light and a second plurality of pulses among the pulses of light (signals indicative of desired peak wavelength separation, see [0085]-[0088]), both the first plurality of pulses and the second plurality of pulses provided during the single exposure pass (both wavelengths exposed during a single exposure pass, λ1 during exposure via strips 310-318 and λ2 during exposure via strips 322-330, see Fig. 18 and [0069]-[0072]), the second plurality of pulses being distinct from the first plurality of pulses (distinct pulse numbers with distinct wavelengths, see Figs. 7,8, and 18 and [0069]-[0072]); and
a control module (wavelength control module 220, see Figs. 16 and 17, and associated dose controller, see [0019] and [0090]) coupled to the communications interface and the processor and configured to generate adjustment signals in response to the input signals (signals for controlling the dose and wavelength, see Figs. 16 and 17, [0019], and [0085]-[0090]), the adjustment signals provided to the spectral feature selection module (signal provided to wavelength selecting by control the tuning mirror, see [0085]), wherein:
the adjustment signals are configured to initiate rotations to a tuning mirror of the spectral feature selection module between a first rotational state producing a first angle of light incident on the grating for the first plurality of pulses and a second rotational state producing a second angle of light incident on the grating for the second plurality of pulses (tuning mirror tilt angle adjusted to control location of light and thereby changing location on the dispersive wavelength selection optic, see [0054]-[0056], [0064]-[0066], [0071], and [0079]-[0089]) to thereby to adjust an amount of optical energy delivered with the first plurality of pulses and an amount of optical energy delivered with the second plurality of pulses (control signals for doses applied for each wavelength, see [0019], [0045]-[0047], where RELAX is implemented by the controller 290 based on signal from scanner, see [0085]-[0088]).
Sandstrom also teaches articulated optical elements, e.g., the variably refractive optical elements, e.g., inserted in the optical path between the laser and the grating in existing line narrowing modules in paragraphs [0042] and [0087], but fails to explicitly teach rotations to one of the prisms of the spectral feature selection module between a first rotational state producing a first angle of light incident on the grating for the first plurality of pulses and a second rotational state producing a second angle of light incident on the grating for the second plurality of pulses.
Algots teaches an expander (64 and 82-88, see Figs. 1-5) where controlled rotations to one of the prisms of the spectral feature selection module between a first rotational state producing a first angle of light incident on the grating for the first plurality of pulses and a second rotational state producing a second angle of light incident on the grating for the second plurality of pulses (pulse to pulse adjustment of center wavelength by rotating prisms 82-88, see [0043] and [0058]).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to include the rotation of the prism of a beam expander to change wavelength pulse to pulse as taught by Algots in the laser narrowing module as taught by Sandstrom in order to provide for “various levels of fine tuning of the angle of incidence on the grating to overcome issues engendered, e.g., by increasing repetition rate and/or mechanical resonances”.
For claims 20 and 26, Sandstrom teaches the input signals comprise an indication that a single primary wavelength is to be used for a series of pulses among the pulses of light (central wavelength, see Figs. 6-8 and 16-18 and [0085]-[0088]).
For claims 21 and 27, Sandstrom teaches the input signals comprise an indication of one or more primary wavelengths of the pulses of light (first and second center wavelengths, see Figs. 6-8 and 16-18 and [0085]-[0088]).
For claims 22 and 28, Sandstrom teaches the control module is configured to control a first primary wavelength of the first plurality of pulses and a second primary wavelength of the second plurality of pulses, such that spectra of the first and second set of pulses are spectrally distinct (first and second wavelength control based on pulse to pulse or series of pulses, see [0085]-[0088]).
For claim 24, Sandstrom teaches the processor is configured to identify, within the input signals, the indications of the timing of pulses and to trigger pulses of light emitted by the pulsed light source based on the indications of the timing of pulses (laser pulse timing and repetition rate, see Figs. 16 and 17 and [0085]-[0088]).
For claim 25, Sandstrom teaches the processor is configured to identify, within the input signals, the indication of the spectral separation and to dither or switch a wavelength of pulses of emitted by the pulsed light source based on the indication of the spectral separation (first and second wavelength control based on pulse to pulse or series of pulses, see [0085]-[0088]).
For claim 34 and 43, Sandstrom teaches the pulsed light source is a two-stage laser system comprising a master oscillator providing a seed light beam to a power amplifier (MOPA, see [0039]).
For claims 36 and 45, Sandstrom teaches a spectral separation between the first primary wavelength and the second primary wavelength is 200 femtometers to 5 picometers (20 pm, see [0057]).
For claims 37 and 46, Sandstrom teaches a first aerial image is formed at a first plane based on the first primary wavelength and a second aerial image is formed at a second plane based on the second primary wavelength (two different optimal focal planes, see [0017]).
For claims 38, 47, and 48, Sandstrom teaches a separation distance between the first plane and the second plane is based on: a desired depth of focus and dose variation at a lithography apparatus (desired DOF and exposure latitude, see [0017], for desired separation, see [0085]-[0088]); or a spectral separation between the first primary wavelength and the second primary wavelength and properties of a projection optical system through which the pulses of light pass prior to reaching the first plane and the second plane (desired peak separation from scanner, see [0085]-[0088], using the projection aligner for imaging two planes, see [0008]-[0012]).
For claims 49 and 51, Sandstrom teaches during the single exposure pass, aerial images at different locations along a z axis of a wafer are formed from the pulses of the light without moving a projection optical system through which the pulses of light pass relative to the wafer (expanded DOF by using two wavelengths providing different image points, se [0004]).
Response to Arguments
Applicant's arguments filed on February 17, 2026 have been fully considered but they are not persuasive.
The Applicant argues on page 8 of the Remarks that the variable wedges described in paragraph [0058] of Sandstrom are provided at a position prior to the beam expander and therefore cannot meet claim limitation of being used form a beam expander.
The Examiner respectfully disagrees. The position of the wedges 100 and 100’can be in a high magnification zone or a low magnification zone of the expander and therefore still be a part of the prism chain that adjusts the beam width. Also, the wedges inherently act to expand due to the nature of an optical wedge.
Additionally, the arguments are also 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. Algots is relied upon to teach the expander and associated rotational function of the prisms.
Conclusion
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/Steven H Whitesell/Primary Examiner, Art Unit 1759
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