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 .
Response to Amendment
Applicant’s amendment filed on May 08, 2026 has been acknowledged and entered.
Currently, claims 1-13 are pending.
Response to Arguments
Applicant's arguments filed on 05/08/026 have been fully considered but they are not persuasive.
First of all, a reference need not disclose every claim limitation in the same words. It is enough if the reference teaches the same or closely related problem, discloses the same or closely related technical approach, and make the claimed modification a predictable use of prior art elements. (See generally KSR Int’l Co. v. Teleflex Inc., 550 US 398 (2007); MPEP § 2141 and § 2143.
Nagahama clearly teaches: an illumination optical system with a lens array; a measurement sensor that measures light quantity/intensity; stage movement of the lens array or measurement platform; the problem of ghost images caused by periodic illumination / phase grating / stray diffraction; using measured light values and threshold-based control; recording values at different positions and comparing/sorting them. relevant passages include: ¶0022, ¶0031–¶0044: optical image acquisition mechanism, lens array stage, light amount sensor, illumination optics; ¶0050–¶0056: lens-array-induced concentrated irradiation causing phase grating and ghost image; ¶0064–¶0072: shifting lens array based on integrated light threshold to suppress ghost image; ¶0129–¶0146: measuring ghost-image gradation values and recording them by position; sorting and selecting based on those values. So, Nagahama unquestionably addresses ghost-image suppression/monitoring in an optical illumination context.
Further, applicant argues that Nagahama is “just mask inspection” and not “the illumination unit of a lithography machine.” That argument is too narrow for obviousness. Nagahama’s background explicitly concerns semiconductor lithography-type optical exposure contexts: ¶0002: semiconductor elements are manufactured by exposing and transferring patterns using a reduction projection exposure apparatus (stepper/reticle/mask environment). Even though the detailed embodiments are framed as pattern inspection, the optical principles and components are the same family of lithographic illumination systems. The claim language is also broad: “illumination unit of a lithography machine”; “lens”; “measurement platform”; “light intensity uniformity sensor”. The examiner does not need Nagahama to describe a finished production scanner with wafer exposure shot stitching. It is enough if Nagahama teaches the same optical physics and control approach in an adjacent lithography-related optical system.
Applicant argues that Nagahama does not disclose lens area/peripheral area/central area. Even if those exact labels do not appear, the prior art teaches spatially distinct regions of the illumination field, a reference measurement region, outer regions associated with stray/ghost effects, repeated position-specific measurements. Under 103, an artisan would have found it obvious to define and use a central/reference area and peripheral measurement area for normalization of ghost-related intensity.
The applicant is arguing that the cited reference solves a different problem. But that does not defeat obviousness if the cited art teaches: the same optical phenomenon (ghosting caused by concentrated illumination / phase grating), the same need to monitor/avoid it, and the same kind of sensor/stage-based measurement methodology.
That is enough to support an obviousness combination or adaptation.
The applicant argues that Nagahama’s light quantity sensor does not move. That is true in a literal sense, but not fatal. The claim requires a movable measurement platform, not necessarily a sensor with internal mobility. The prior art teaches movable stages and spatially indexed measurements. If needed, the Office can rely on the general principle that moving the sensor on a stage to sample different regions of an optical field is a routine and predictable design choice.
Applicant argues that Nagahama does not disclose dividing second intensity by reference value. Nagahama repeatedly measures values, compares them to reference values, records them by position, sorts and uses them for control. Normalizing by a reference intensity is a routine analytical step. The claim’s ratio is an expected way to express relative scattered light / ghost strength.
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1-13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Nagahama et al., (hereinafter Nagahama), JP 2023-105899.
As to claim 1, Nagahama discloses a method for monitoring ghost image of an illumination unit of a lithography machine, comprising:
Step 1: the illumination unit of the lithography machine comprising a lens and a measurement platform with light-intensity uniformity sensor provided on the measurement platform; (Fig. 1 is a configuration diagram showing the configuration of the pattern inspection apparatus according to first embodiment. In Fig. 1, an inspection apparatus 100…includes an optical image acquisition mechanism 150 and a control system circuit 160…”[¶0021]; “The optical image acquisition mechanism 150 includes a light source 103 that generates laser light, a Koehler illumination optical system 300, a lens array stage 320, a drive mechanism 322, a relay lens 31, a beam splitter 32, a reflected illumination optical system 270, an XYθ table 102, and an objective lens 104, ….and a light amount sensor 324.” [¶0022]; Fig. 1. This teaches the claimed illumination unit (lens 104) and a measurement platform/stage (lens array stage 320/XYθ table 102) carrying a light-intensity sensor (light amount sensor 324).
setting a lens are, a peripheral area, and a central area on a moving plane of the measurement platform; the lens area being located in an internal area of an edge line formed after illuminating an edge of the lens, the central area being a selected area within the lens area, a center point of the central area being a center point of the lens area; the peripheral area being located on an outer side of the lens area, light leakage in the peripheral area causing the ghost image; (Nagahama explains ghost images arising from lens illumination/phase gratings and defines measurement/shift regions (lens-area interior, central, and surrounding/outer positions): “In the first embodiment, irradiation traces (degraded images) degraded to such an extent that the corresponding condensing points 34 (intermediate images) form a phase grating are formed in a shift region 36 surrounded by four adjacent condensing points 34 (intermediate images).” [¶0067]; Figs. 7–11. “In contrast, in Embodiment 1 … each irradiation position of the objective lens 104 is shifted by shifting the lens array 304 each time the integrated amount of light reaches the threshold value… the entire area surrounding the condensing point 12 … is filled with the condensing point 12. Therefore, formation of irradiation traces on the objective lens 104 can be prevented.” [¶0071]; Figs. 10–11.“In the mark scanning step (S108), an image of the substrate 101 obtained by irradiating the substrate 101 on which the mark pattern is formed with inspection illumination light (first light) is captured by the imaging sensor 105…” [¶0122]; Fig. 22. Taken together, Nagahama teaches measuring within the illuminated lens area (interior of the edge line), using a central region within that area, and measuring in outer/peripheral positions where stray illumination leads to ghosting (see Figs. 3–6, 22–26 and the accompanying explanation of ghost image formation by phase gratings and stray light).
step 2: turning on the illumination unit, moving the measurement platform to move the light intensity uniformity sensor to the central area, measuring first light intensity in the central area, and obtaining a reference value from the first light intensity (Nagahama describes establishing a baseline/reference from mark images acquired when no ghosting is present, and then using that reference for subsequent ghost-value calculations: “As the reflection gradation value calculation step (S110), the reflection gradation value calculation unit 51 calculates the gradation value of the ghost image reflected in the mark image. Specifically, the difference value obtained by subtracting the gradation value at the same position in the reference mark image in which the ghost image does not occur from the gradation value of the pixel straddling the edge portion of the imaged mark pattern shown in FIG. calculate.” [¶0129]; Fig. 22. “In the mark image obtained in the first mark scanning step (S108) after shifting the lens array 304, no ghost image is reflected yet, so it is preferable to use this mark image as the reference mark image.” [¶0129]. These passages correspond to moving to and measuring central-area intensities and using the initial central measurement(s) as the reference.)
step 3: moving the measurement platform to move the light intensity uniformity sensor to a selected position in the peripheral area, and measuring second light intensity at the selected position in the peripheral area; (Nagahama teaches acquiring and recording pre-position measurement values (ghost gradations) for different coordinates (peripheral positions) associated with the stage/lens array location: “As a recording processing step (S112), the recording processing unit 52 records the calculated gradation value of the ghost image (reflection gradation value) in the storage device 53 in association with the arrangement position coordinates of the lens array 304 [¶0132]. “As the lens array shift step (S120), the shift processing unit 58 controls the stage control circuit 140 to shift the position of the lens array 304 to the next position…..The lens array 304 is shifted so that each position in the shift region 36 corresponding to the condensing point 12 of each split light is irradiated once in a random order.” [¶0138–¶0139]; Fig. 23 (movement table), Gig. 24 (sorted table). These disclosures teach acquiring measurements at selected positions (coordinates) in the region outside the central area (peripheral portions) and recording the pre-position values.
Step 4: dividing the second light intensity by the reference value to obtain a ratio as a scattered-light monitoring value for the ghost image. (Nagahama discloses comparing/normalizing per-position ghost values against baseline/reference, and processing/sorting those values. “As the sorting process (S130), the sorting unit 59 sorts the gradation values of the ghost images recorded at each position of the k-th lens array 304 in ascending order [¶0142]; Fig. 24. “As the order determination step (S132), the order determination unit 61 ….determines the order of movement of each position of the k+1-th round of the lens array 304 in ascending order of the gradation value of the ghost image.” [¶0144]. Nagahama further shows normalized/relative plotting of ghost intensity versus position (see Figs. 25-26; “relationship between shift position and reflection intensity”).
Although Nagahama does not explicitly recite, “dividing”, he teaches computing and comparing per-position ghost metrices relative to a reference. Forming a ratio (peripheral value divided by central reference value) is a routine normalization step in optical metrology that would have been obvious to a person of ordinary skill in the art in view of the cited processing (recording, comparison, sorting, and normalization/plotting of ghost-related gradation values. See, e.g., Nagahama [¶0142–¶0144]; Fig. 24) and Figs. 25–26 (plots relating position to reflection intensity).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to divide the second light intensity by the reference value to obtain a first ratio as a scattered light monitoring value for the ghost image because such an element represents a routine data-processing or presentation choice that would yield predictable results.
As to claim 2, Nagahama discloses method for monitoring ghost image of an illumination unit of a lithography machine according to claim 1, wherein in step 4, the first ratio is multiplied by 100 or 100% as the scattered light monitoring value. (Nagahama discloses normalized/relative metrices and plotting (see “sorted movement table” and reflection-intensity plots at Fog. 24’ Figs. 25-26; [¶0142–¶0148]). Even though Nagahama doesn’t explicitly disclose, “the first ratio is multiplied by 100 or 100% as the scattered light monitoring value”, converting a computed ratio to percentage is a routine, expected data-presentation step and thus would have been obvious to achieve predictable result.
As to claim 3, Nagahama discloses the method for monitoring ghost image of an illumination unit of a lithography machine according to claim 1, wherein the measurement platform is moved stepwise along an X direction or a Y direction. (“The drive mechanism 322 has, for example, an x-axis motor, a Y-axis motor, and a θ-axis motor….The lens array stage 320 is driven by X/Y/θ motors.” [¶0033]. “In the first embodiment, the order of irradiating a plurality of small regions is determined randomly…the condensing point (intermediate image) is also shifted to the remaining positions in the shift area 36 in any order after the sixth shift.” [¶0069]. Flowcharts (Figs. 21, 28-29) depict stepwise scanning and repeated movement measurement cycles.
As to claim 4, Nagahama discloses the method for monitoring ghost image of the illumination unit of the lithography machine according to claim 3, wherein a step size for moving the measurement platform along the X direction is a first step size, and the first step size is pre-set before step 2 and is adjustable; and a step size for moving the measurement platform along the Y direction is a second stepsize, and the second step size is pre-set before step 2 and is adjustable. (Nagahama discloses controlled stage motions (stepwise and continuous), and the selection/configuration of scan parameters is a routine design choice. “Further when the lens array 304 is shifted by parallel movement and/or rotational movement, the movement is not limited to step movement. It may be a case of shifting by continuous movement.” [¶0078]. Setting and adjusting step size (before scanning) is an obvious parameterization of the disclosed stage control (see [¶0033], [¶0078]) and would have been obvious to one of ordinary skill in the art to achieve predictable result.
As to claim 5, Nagahama discloses the method for monitoring the ghost image of the illumination unit of the lithography machine according to claim 4, wherein coordinates of the selected position in step 3 are changed, and then step 3 and step 4 are repeated to obtain scattered light monitoring values at selected positions with different coordinates. (Nagahama expressly teaches recording ghost values at different coordinates and building a movement table. “records the calculated gradation value…in association with the arrangement position coordinates of the lens array 304” [¶0132]; Fig. 23; Further, repeating steps 3 and 4 at different coordinates is an obvious way to gather more data and thus would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to repeat steps 3 and 4 at different coordinates to achieve predictable results.
As to claim 6, Nagahama discloses the method for monitoring the ghost image of the illumination unit of the lithography machine according to claim 5, wherein the coordinates of the selected position in step 3 are continuously changed by moving stepwise along the X direction or the Y direction to achieve a measurement of a scattered light monitoring value at each position in a sub-area of the peripheral area. (Nagahama teaches stepwise scanning of positions within the shift region and recording per-position values (see [¶0138–¶0139], Fig. 23).
As to claim 7, Nagahama discloses the method for monitoring the ghost image of the illumination unit of the lithography machine according to claim 6, wherein the coordinates of the selected position in step 3 are continuously changed by moving stepwise along the X direction or the Y direction to achieve the measurement of scattered light monitoring values at all positions in the peripheral area. (Nagahama teaches completing full rounds of positions within shift regions and recording values at each position (see [¶0138–¶0139], [¶0141–¶0146]; Figs. 21, 23–24).
As to claim 8, Nagahama discloses he method for monitoring the ghost image of the illumination unit of the lithography machine according to claim 1, wherein the illumination unit further comprises a light source, and a wavelength of the light source comprises 365nm, 248nm, or 193nm. (Nagahama discloses DUV laser illumination for inspection. “The light source 103 emits, for example, a laser light (for example, DUV light) having a wavelength of about 190 to 200 nm …” [¶0040]). The enumerated lithography wavelengths (365/248/193 nm) are conventional industry wavelengths within the domain taught by Nagahama. Selecting such wavelengths would have been an obvious design choice in this context to achieve predictable results.
As to claim 9, Nagahama discloses the method for monitoring the ghost image of the illumination unit of the lithography machine according to claim 1, wherein the lithography machine is a scanner lithography machine. (Nagahama’s background places the invention squarely in stepper/scanner environments: “These semiconductor elements are manufactured by exposing and transferring the pattern onto a wafer using a reduction projection exposure apparatus called a stepper using an original image pattern (also called a mask or reticle…).” [¶0002].
As to claim 10, Nagahama discloses the method for monitoring the ghost image of the illumination unit of the lithography machine according to claim 1, wherein a size of a wafer exposed by the lithography machine comprises 200nm, 300nm, or 450nm. Such wafer sizer are standard in lithography practice and are within the general environment disclosed in Nagahama (see [¶0002]–[¶0004]). Selection among standard wafer sizes is an obvious design choice and thus would have been obvious to obtain predictable result.
As to claim 11, Nagahama discloses The method for monitoring the ghost image of the illumination unit of the lithography machine according to claim 4, wherein, in step 2, a moving direction and distance of the measurement platform are continuously changed by moving stepwise along the X direction or the Y direction to achieve a measurement of the first light intensity at all positions in the central area, and an average value of the first light intensity at all positions in the central area is used as the reference value. (Nagahama teaches multi-point central measurements and using reference mark images to establish baseline values (see [¶0129]; Figs. 21–22). Averaging across central-area data points is a routine data-reduction step within ordinary skill and consistent with Nagahama’s multi-point recording/processing (see [¶0132], [¶0136]).
As to claim 12, Nagahama discloses the method for monitoring the ghost image of the illumination unit of the lithography machine according to claim 4, wherein the method further comprises: step 5: moving the measurement platform to move the light intensity uniformity sensor to the lens area outside the central area to achieve a measurement of third light intensity in the lens area outside the central area. (Nagahama teaches scanning across positions within the lens/shift regions beyond the central location and recording per-position values (see [¶0136], [¶0138–¶0139]; Fig. 23).
As to claim 13, Nagahama discloses the method for monitoring the ghost image of the illumination unit of the lithography machine according to claim 12, wherein, in step 5, a moving direction and distance of the measurement platform are continuously changed by moving stepwise along the X direction or the Y direction to achieve the measurement of the third light intensity at all positions in the lens area outside the central area. (Nagahama teaches repeated scanning and recording across the region (see Figs. 21, 23–24) renders the limitation obvious.
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 TARIFUR RASHID CHOWDHURY whose telephone number is (571)272-2287. The examiner can normally be reached M-F: 8 am-5 pm.
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/TARIFUR R CHOWDHURY/Supervisory Patent Examiner, Art Unit 2877
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