DETAILED ACTION
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, 2, 4, 6-11, 13, 19, 20, and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Slotboom et al [US 2018/0373162] in view of Sho [US 2017/0263508].
For claims 1, 19, and 20, Slotboom teaches a metrology system and associated method (see Figs. 4-7) comprising:
a controller (SCS 328 and LIS control systems, see Figs. 4 and 7) communicatively coupled to an optical metrology sub-system (scatterometer, see [0081], [0087], and [0108]) and an additional metrology sub-system (SEM, see [0110]) including at least one of a particle-beam metrology system or an x-ray metrology system,
wherein the optical metrology sub-system is configurable in accordance with a first metrology recipe to generate optical metrology measurements of one or more optical metrology targets on one or more samples (measurement of overlay targets using measurement recipe, step 116, see [0106]-[108]),
wherein the optical metrology measurements are based on features of the optical metrology targets associated with at least one optical pitch (metrology targets having grating pitch, see Fig. 5 and [0085]),
wherein the optical metrology measurements are based on the features of the optical metrology targets with the at least one optical pitch (captured scatter diffraction patterns, see [0081]);
wherein the additional metrology sub-system is configurable in accordance with a second metrology recipe to generate additional metrology measurements of the one or more optical metrology targets (configuration of the reference technique, see [0110]),
wherein the additional metrology measurements have a higher resolution than the optical metrology measurements (scanning electron microscopy has a higher resolution than scatterometry),
wherein the controller includes one or more processors configured to execute program instructions causing the one or more processors (processors for performing process, see [0140]) to:
compare the optical metrology measurements with the additional metrology measurements to generate accuracy measurements for the one or more optical metrology targets (metrology data compared with reference data using PCA, see [0110]-[0112]);
and adjust at least one of the optical metrology sub-system, a lithography tool, or the reference design based on a correlation with the overlay comparison (correlate the variation in metrology data, see [0112] and the iterative process of changing the recipe in Fig. 6),
wherein the adjustment includes modifying the first metrology recipe (the best combination of metrology target type and metrology recipe is identified as the one which has the least variation between its overlay values and those reported by the reference technique, see [0112] and the iterative process of changing the recipe in Fig. 6).
Slotboom teaches that known asymmetry can be introduced to provide further control using the reference technique (see [0110]), and that sidewall angle and critical dimension can be used for further process control (see [0079]-[0080]), but fails to explicitly teach the additional metrology sub-system in configured to measure deviations of the one or more optical metrology targets from a reference design, wherein the deviations include measurements of feature asymmetry within the one or more optical metrology targets, wherein the deviations include deviations of the optically-resolvable features from the reference design, wherein the comparison includes evaluating feature asymmetry, identify variations of a lithography process for fabricating the one or more samples based on the deviations of the one or more optical metrology targets from the reference design; correlate the accuracy measurements of the one or more optical metrology targets to the variations of the lithography process based on the deviations of the one or more optical metrology targets from the reference design; and the adjustment includes modifying the first metrology recipe to account for detected feature asymmetry.
Sho teaches the additional metrology sub-system in configured to measure deviations of the one or more optical metrology targets from a reference design, wherein the deviations include measurements of feature asymmetry within the one or more optical metrology targets (asymmetry measurement by SEM apparatus 107, see [0039]-[0041]),
wherein the deviations include deviations of the optically-resolvable features from the reference design (asymmetry of target used for optical overlay measure, see [0038]-[0040] and Fig. 2A-2B and 7A-7B),
wherein the comparison includes evaluating feature asymmetry (determining asymmetry relation with overlay measurement, see [0041]),
identify variations of a lithography process for fabricating the one or more samples based on the deviations of the of the one or more optical metrology targets from the reference design (process condition associations with overlay and asymmetry, see [0042] and Figs. 8 and 9);
correlate the accuracy measurements of the one or more optical metrology targets to the variations of the lithography process based on the deviations of the one or more optical metrology targets from the reference design (generate calibration curve, see Fig. 8 and [0045]);
adjust at least one of the optical metrology sub-system, a lithography tool, or the reference design based on the correlation (process correction see Fig. 9),
wherein the adjustment includes modifying the first metrology recipe to account for detected feature asymmetry (measurement correction, see [0051]).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to use a correlation relationship between overlay measurement accuracy, asymmetry target data collected from the SEM , and process conditions as taught by Sho in the recipe optimization using correlated component vectors with overlay data and reference data as taught by Slotboom, because Sho recognizes that asymmetry of the target caused by process conditions influences measurement error of overlay shift and can be used to determine corrections and correlations in order to provide more accurate overlay shift measurement.
For claim 2, in the combination of Slotboom and Sho, Sho teaches measuring deviations of the one or more optical metrology targets from reference designs based on the additional measurements comprises: measuring at least one of sidewall angles, asymmetries (asymmetry, see [0040]), pattern placement errors, or etch bias of the features associated with the at least one optical pitch.
For claim 4, in the combination of Slotboom and Sho, Sho teaches measuring deviations of the one or more optical metrology targets from reference designs based on the additional measurements comprises: measuring layer-specific deviations of the one or more optical metrology targets (measuring calibration for each layer/film, see Fig. 10).
For claim 6, in the combination of Slotboom and Sho, Sho teaches identifying variations of the lithography process for fabricating the one or more samples based on the deviations of the of the one or more optical metrology targets from the reference design comprises: identifying variations of the lithography process between different spatial locations across a particular one of the one or more samples (asymmetry measure at marks at different locations across wafer, see Fig. 1).
For claim 7, in the combination of Slotboom and Sho, Sho teaches the one or more samples includes two or more samples, wherein identifying variations of the lithography process for fabricating the one or more samples based on the deviations of the of the one or more optical metrology targets from the reference design comprises: identifying variations of the lithography process across time for at least two of the two or more samples (control for a plurality substrates, see [0032] and [0056]).
For claim 8, Slotboom teaches adjusting at least one of the optical metrology sub-system, the lithography tool, or the reference design based on the correlations comprises: adjusting the first metrology recipe to decrease a sensitivity of the optical metrology measurements to the variations of the lithography process (robustness of mark optimization including different recipes, see [0093], [0106], and [0127]).
For claim 9, Slotboom teaches adjusting the first metrology recipe to decrease a sensitivity of the optical metrology measurements to the excursions comprises: adjusting at least one of an illumination wavelength, an illumination polarization, an illumination angle, or a field of view of the optical metrology sub- system (parameters of the scatterometer are recipe elements, see [0081]).
For claim 10, Slotboom teaches adjusting at least one of the optical metrology sub-system, the lithography tool, or the reference design based on the correlations comprises: adjusting the lithography tool to compensate for the variations of the lithography process (exposure apparatus process correction, see [0132]).
For claim 11, Slotboom teaches adjusting at least one of the optical metrology sub-system, the lithography tool, or the reference design based on the correlations comprises: switching the reference design to an alternative reference design; and directing the lithography tool to fabricate one or more additional optical metrology targets on one or more additional samples based on the alternative reference design (optimization with different the alignment mark type, see [0112]-[0116]).
For claims 13 and 22, Slotboom teaches the optical metrology sub-system generates the optical metrology measurements based on one or more scatterometry measurements (see [0108]) of the one or more optical metrology targets.
Claims 3, 12, 14-16, 21, and 23-25 are rejected under 35 U.S.C. 103 as being unpatentable over Slotboom in view of Sho as applied to claims 1 and 20 above, and further in view of Amir et al. [US 2014/0065736].
For claim 3, Slotboom teaches measuring at least one of sidewall angles, asymmetries, pattern placement errors, or etch bias of the features (see [0079]-[0080]) and Sho teaches measuring at least one of sidewall angles, asymmetries, pattern placement errors, or etch bias of the features (asymmetry measurement by SEM apparatus 107, see [0039]-[0041]).
Slotboom fails to teach the one or more optical metrology targets further include features associated with a fine pitch smaller than the at least one optical pitch, wherein measuring deviations of the one or more optical metrology targets from reference designs based on the additional measurements is associated with the fine pitch.
Amir teaches the one or more optical metrology targets further include features associated with a fine pitch smaller than the at least one optical pitch, wherein measuring deviations of the one or more optical metrology targets from reference designs based on the additional measurements is associated with the fine pitch (fine pitch for measurement with the SEM that is smaller than coarse pitch, see [0026]-[0031]).
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 fine pitch for measurement used to calibrate the optical metrology device as taught by Amir in the optimization as taught by Slotboom in order to increase the accuracy of the overlay measurement by using calibration targets that are designed to provide a device feature sized pitch.
For claims 12 and 21, Slotboom fails to teach the optical metrology sub-system generates the optical metrology measurements based on one or more images of the one or more optical metrology targets.
Slotboom teaches the optical metrology sub-system generates the optical metrology measurements based on one or more images of the one or more optical metrology targets (scatterometry or imaging overlay optical tools, see [0023] 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 provide the imaging metrology as taught by Amir as the optical tool as taught by Slotboom because of the art recognized suitability for providing either imaging or scatterometry type metrology for optically measuring the lithographically formed targets.
For claims 14-16 and 23-25, Slotboom fails to teach the at least one optical pitch includes a single optical pitch, wherein the one or more optical metrology targets include features with the single optical pitch on at least two layers, wherein the at least one optical pitch includes a first optical pitch and a second optical pitch, wherein the first and second optical pitches are resolvable with the optical metrology sub-system.
Amir teaches the at least one optical pitch includes a single optical pitch, wherein the one or more optical metrology targets include features with the single optical pitch on at least two layers, wherein the at least one optical pitch includes a first optical pitch and a second optical pitch, wherein the first and second optical pitches are resolvable with the optical metrology sub-system (optical pitches used for imaging and scatterometry overlay measurement, see claims 9-12).
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 overlay optical targets as taught by Amir in the targets to measure process variables as taught by Slotboom because overlay targets allow for determining systematic lithographic process errors that are determined by optical metrology.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Slotboom in view of Sho as applied to claim 1 above, and further in view of Martin et al. [US 2003/0124439].
For claim 5, Slotboom fails to teach the one or more optical metrology targets include features distributed with one or more pitches, wherein measuring deviations of the one or more optical metrology targets from reference designs based on the additional measurements comprises: measuring pitch-specific deviations of the one or more optical metrology targets.
Martin teaches the one or more optical metrology targets include features distributed with one or more pitches, wherein measuring deviations of the one or more optical metrology targets from reference designs based on the additional measurements comprises: measuring pitch-specific deviations of the one or more optical metrology targets (see [0019]).
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 measurement of pitch deviation as taught by Martin in the optimization as taught by Slotboom because identifying pitch walk allows for identifying process control error in stage movement and pattern placement.
Claims 17 and 26 are rejected under 35 U.S.C. 103 as being unpatentable over Slotboom in view of Sho as applied to claims 1 and 20 above, and further in view of Yang et al. [US 2019/0219930].
For claims 17 and 26, Slotboom fails to teach the one or more optical metrology targets include features with a first pitch and a second pitch, wherein at least one of the first or the second pitches are not resolvable with the optical metrology sub-system, wherein the optical pitch comprises a Moiré pitch based on the first and second pitches and is resolvable by the optical metrology sub-system.
Yang teaches the one or more optical metrology targets include features with a first pitch and a second pitch, wherein at least one of the first or the second pitches are not resolvable with the optical metrology sub-system, wherein the optical pitch comprises a Moiré pitch based on the first and second pitches and is resolvable by the optical metrology sub-system (see [0025]).
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 Moiré pitch of the target as taught by Yang in the target as taught by Slotboom in order to minimize the interference between the signal from top/bottom gratings to Moiré pitches, and this enhances the Moiré pitch contrast significantly to accurately measure overlay in an imaging tool and control of processes associated with overlay error.
Response to Arguments
Applicant's arguments filed on November 14, 2025 have been fully considered but they are not persuasive. The Applicant argues on pages 10-12, regarding claims 1, 19, and 20, that the combination of Slotboom and Sho fails to teach “adjust at least one of the optical metrology sub-system, a lithography tool, or the reference design based on the correlations, wherein the adjustment includes modifying the metrology recipe to account for detected feature asymmetry,” because A) Slotboom does not dynamically rewrite the first optical metrology recipe in production in response to asymmetry measurements from a higher-resolution tool, B) Sho teaches post-measurement numerical offsets and not changes to the optical microscope's recipe parameters, and C) the rationale to combine supports Sho's numerical correction of measured overlay values, not the claimed reconfiguration of the optical metrology recipe parameters (e.g., wavelength, polarization, angle, FOV) expressly to account for detected asymmetry.
The Examiner respectfully disagrees.
A) Slotboom teaches in Fig. 6 at step 620 iteratively changing optical metrology recipes (which include the identified parameters, see [0081] and [0108]) and marks until the minimum distance between the measurement by optical metrology device and the reference technique is achieved. Each change of recipe is a modification to the first metrology recipe.
B) There is no special definition for the claimed “first metrology recipe”. A metrology recipe can include scaling or shifting based on external information about the metrology error that is inherent to the recipe, including modification by numerical correction. Further, Slotboom recites in paragraph [0081] that the manner of analyzing any captured scatter diffraction patterns, can be specified in a metrology recipe. A correction that occurs before the application of the metrology output to correct the lithographic process can be considered a part of the metrology recipe. The numerical correction as taught by Sho can be appended to the metrology recipe optimization of Slotboom. The correlation shown in Figs. 8 and 9 of Sho can be used in the combination as the correlation information between the optical measurement and the reference technique to incorporate process condition information in the correction, increasing the accuracy of the correlation information used by Slotboom in paragraph [0112].
C) Slotboom is relied upon to teach the modification of the recipe through the iterative process. Sho is relied upon to teach the correlation information based on deviation from the reference design that is then used to modify a measurement recipe. In the combination, the correlation information as taught by Sho is used in the analysis for recipe modification as taught by Slotboom.
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.
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/Steven H Whitesell/Primary Examiner, Art Unit 1759