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 .
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 07/30/2026 has been entered.
Response to Amendment
Applicant’s amendment filed on 07/10/2026, amending claim 1 has been acknowledged and entered.
Currently claims 1-13 are pending.
Response to Arguments
Applicant's arguments filed on 07/10/2026 have been fully considered but they are not persuasive.
Applicant’s arguments:
a) Applicant argues that amended claim 1 further limits the lens area by the main pattern area of the mask and defines a one-to-one correspondence among the lens area, main pattern area, and shot during exposure; and further defines the relationship between the peripheral area at the measurement platform and scattered light / ghost image.
b) Applicant argues that Nagahama does not disclose main pattern area and peripheral pattern area related to the mask, and therefore does not disclose the claimed lens area and peripheral area defined by those mask areas.
c) Applicant contends that if a reference only discloses light intensity measurement generally, without limiting the measurement areas, then the first and second light intensities of claim 1 cannot be obtained.
d) Applicant argues that the second light intensity is related to ghost image of another shot on the wafer, and that only the claimed ratio can serve as a monitoring value.
e) Applicant argues that Nagahama does not specifically disclose using light sensor 324 to separately measure the lens area and peripheral area at the measurement platform.
Examiner’s response:
a) In response, it is respectfully pointed out to applicant that the admitted prior art of the instant application expressly describes the conventional lithography exposure relationship in which: a main pattern area on the mask is transferred to a shot on a wafer; a peripheral pattern area exists on the mask; scattered light passing through the peripheral pattern area can enter an adjacent shot and create a ghost image.
That disclosure teaches the exact exposure-context relationship applicant relies on. The fact that applicant has restated that known lithography environment in the claim does not confer patentability. These added statements merely describe the known operating environment of a lithography machine and the known ghost-image mechanism. Nagahama A already discloses the monitoring structure: a lens area, a central area, a peripheral area, measurement of first and second light intensity, and computation of a ratio as a ghost-image monitoring value. In view of the admitted prior art, it would have been obvious to understand the Nagahama monitoring method as being applied within the conventional lithography exposure environment.
14. b) In response, it is respectfully pointed out to applicant that first, the current rejection does not rely on Nagahama alone. The rejection relies on Nagahama in view of the admitted prior art. The admitted prior art supplies the lithography exposure context, including the main pattern area and peripheral pattern area relationship. Second, applicant’s argument improperly reads the claim too narrowly. The claim does not require the lens area and peripheral area to be explicitly labeled in the prior art with the same terminology. Rather, the question is whether the combined teachings would have made the claimed arrangement obvious to one of ordinary skill. Nagahama teaches: measuring intensity in a central area and peripheral area on the moving plane of the measurement platform; using the ratio of those measured values to monitor ghost image. The admitted prior art teaches: central exposure effects from the main pattern area; peripheral leakage from the peripheral pattern area; ghost image in an adjacent shot. A person of ordinary skill would have understood that the central-area/peripheral-area monitoring of Nagahama is directed to the same physical phenomenon described in the admitted prior art, namely ghost image caused by peripheral leakage in lithography exposure.
15. c) It is respectfully pointed out to applicant that the argument is not persuasive because Nagahama expressly discloses the required measurement areas. Nagahama teaches: setting a central area on the moving plane; moving the sensor to the central area and measuring first light intensity; moving the sensor to a selected position in the peripheral area and measuring second light intensity; dividing the second by the first to obtain a monitoring value. Thus, the exact structure of the measurement areas and the ratio calculation are expressly taught by Nagahama. The admitted prior art is being used not for the measurement-steps themselves, but for the lithographic exposure relationship and ghost-image mechanism that applicant has newly added. Accordingly, applicant’s assertion that the references do not support comparison of the first and second intensities is incorrect.
16. d) In response, it is respectfully pointed out to applicant that the argument also does not overcome the rejection. Nagahama already teaches that light measured in the peripheral area is used as a scattered light monitoring value for the ghost image. The admitted prior art explains why such scattered light is relevant to ghost image, namely because peripheral-pattern-area light leakage produces unwanted exposure in an adjacent shot. Therefore, the combination of Nagahama and the admitted prior art makes the claimed relationship between peripheral-area measurement and ghost-image monitoring obvious. The claim’s recitation that the ratio is “used as the scattered light monitoring value for the ghost image” is consistent with, and suggested by, the combined teachings of the references.
17. e) It is respectfully pointed out to applicant that the argument is not persuasive. Nagahama does disclose use of a light intensity uniformity sensor on a measurement platform to measure: first light intensity in the central area, second light intensity in a peripheral area, and in some embodiments, third light intensity in the lens area outside the central area. Thus, Nagahama expressly teaches separate measurement of intensities at different areas of the platform. Even if the numerals are not identical to applicant’s terminology, the functional disclosure is the same. Moreover, the admitted prior art supplies the lithography exposure context in which those areas correspond to the mask’s main pattern region and peripheral pattern region. The combined teachings therefore support the claim language.
18. In summary, the newly added limitations are largely explanatory context. Much of the added language in amended claim 1 describes the conventional lithography exposure process and the origin of ghost image. Those statements do not materially distinguish the claim from the cited art because they describe the environment in which the monitoring method operates. The core monitoring method is already taught by Nagahama teaching the essential monitoring steps: measure reference intensity in a central area, measure scattered intensity in a peripheral area, calculate a ratio, use that ratio as a ghost-image monitoring value. The admitted prior art supplies the exposure mechanism. The exact conventional mechanism of ghost image formation: mask main pattern area, peripheral pattern area, transfer to wafer shots, leakage into adjacent shot. Thus the combination is a predictable use of prior art elements. Combining Nagahama’s direct measurement method with the conventional exposure environment taught in the admitted prior art would have yielded predictable results. No new or unexpected technical effect is shown for the added exposure-context language.
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.
19. 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 in view of the applicant’s admitted prior art (AAPA).
20. 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.
Nagahama does not explicitly disclose "using the lithography machine for exposure, and during the exposure, a light from the illumination unit is used to transfer a pattern of a main pattern area on a mask to a shot on a wafer; the measurement platform is located on an optical path through which the light of the illumination unit passes during the exposure, and the lens area is located in a projection area of the main pattern area; during the exposure, the light passing through the edge of the main pattern area of the mask will also pass through the edge of the lens area at the measurement platform and the edge of the shot on the wafer; on a peripheral side of the main pattern area of the mask, there is also a peripheral pattern area; in an exposure process, light passing through the peripheral pattern area of the mask will also pass through the peripheral area at the measurement platform and another shot adjacent to the shot on the wafer, and form a ghost image in the other shot;"
However, the AAPA, particularly Figs. 1 and 2, describes the conventional lithography exposure environment in which: a mask includes a main pattern area and a peripheral pattern area; light from the illumination unit transfers a pattern from the main pattern area to a shot on a wafer; during exposure, light passing through the peripheral pattern area can scatter and be transferred to an adjacent shot, thereby forming a ghost image; and the ghost image results from light leakage/scattered light in the peripheral region during the exposure process. These teachings are admitted prior art because they are set forth in the background of the applicant’s own application and describe the conventional lithography exposure mechanism underlying the invention.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine Nagahama’s sensor-based ghost-image monitoring technique with the conventional lithography exposure context described in the admitted prior art because both references relate to the same field lithography and address the same problem of ghost image caused by peripheral light leakage during exposure and the combination merely applies a known quantitative monitoring method to a known exposure arrangement with predictable results. Therefore, the additional limitations concerning the mask main pattern area, peripheral pattern area, shot, and ghost image in the adjacent shot do not patentably distinguish the claim over the applied references.
21. 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.
22. 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.
23. 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.
24. 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.
25. 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).
26. 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).
27. 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.
28. 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].
29. 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.
30. 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]).
31. 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).
32. 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
33. The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
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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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Allana L. Bidder can be reached at (571)2725560. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/TARIFUR R CHOWDHURY/Supervisory Patent Examiner, Art Unit 2877
