DETAILED ACTION
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 .
Claim Rejections - 35 USC § 103
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 1-3, 5-13, 15, 17-18 are rejected under 35 U.S.C. 103 as being unpatentable over Adel et al (U.S.Pat. 7,804,994) in view of Chang et al (U.S.Pat. 10,866,524).
With respect to claims 1, 5 and 10-12 and 17, Adel discloses a method of manufacturing a semiconductor device comprising substantially all limitations of the instant claims such as: dividing a wafer (100) into a plurality of fields (see figure 3) , wherein the plurality of fields are arranged in rows and column (see figures 3, 5, 6 and corresponding description discussing throughout the field); measuring an overlay errors of a pattern in each of the plurality of fields (see figure 4A; 206) and collecting overlay data and measuring the overlay error of the pattern in the first field among the plurality of fields wherein the correcting the overlay error of the pattern in the first field has dividing the first field into a first region (102) and a second region (104); (see col.5, lines 10-33; col.7, lines 55-67). Adel further teaches using measured overlay information from different locations within a field to establish a mathematical relationship capable of predicting overlay error throughout the field. Specifically, Adel forms calibration relationships between locations and predicts overlay error at device location with the field using those relationships (see figures 2 and 5). Adel further teaches obtaining a correction parameter using the overlay information through mathematical analysis and calculation of correction values (figure 3). Adel does not expressly disclose comparing the overlay error of the first region with the overlay of the second region wherein the second region has an overlay that is greater than an overlay error of the first region; defining a first weight for the first region and a second weight for the second region; obtaining a correction parameter by executing regression using the overlay error data and providing the correction parameter to a scanner. Chang teaches selecting different groups of fields, selecting measurement points within fields, generating overlay correction maps form selected measurement regions and combining overlay correction information from different field groups to improve overlay control (see figures 2A, 2B, 3A-4F, 5A-6b and 7A-7C). Chang therefore teaches treating different portions of measurement data differently depending upon measurement strategy, field grouping, and point selection in order to improve overlay correction accuracy. Finally, Chang expressly teaches providing the generated overlay correction information for lithographic exposure control using the exposing (scanner) (see Figures 1A, 1B, 2A AND 7A). In view of such teachings, it would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to combine the teachings of Adel and Chang to come up with the claimed invention as specified in the claims of the present application. It would have been obvious to a skilled artisan to partition a filed into multiple regions and compare overlay information associated with the respective regions before generating the overlay correction model, since Chang teaches that different field portions and measurement locations may independently selected and combined to improve overlay correction accuracy while reducing measurement burden. Such partitioning merely represents the predictable subdivision of measurement data for improved model accuracy. Furthermore, assigning different weighting significance to measurement regions according to their measured overlay characteristics constitutes an obvious implementation choice for constructing the mathematical overlay model taught by Adel because mathematical modeling routinely allows measurements from different sampling regions to contribute differently to the resulting correction model depending upon their measured characteristics.
As to claim 2, Adel teaches evaluating overlay measurement results to determine overlay characteristics and using the measurement results to establish calibration relationships and determine correction values for lithographic processing. Adel therefore teaches analyzing measured overlay values before determining the correction model. Chang teaches selecting wafers, fields, and measurement points according to computer-generated selection models for the purpose of improving overlay correction accuracy while reducing unnecessary measurements. Chang additionally teaches generating overlay correction maps only from selected measurement data that satisfy the desired measurement strategy (see for examples, Figure 2A, 1B, 5A, 6A and 7A). Although neither Adel nor Chang expressly discloses comparing the overlay error with a specifically named “overlay error limit” before assigning different weights, it would have been obvious to one of ordinary skill in the art to determine whether measured overlay error exceeds an acceptable overlay tolerance before allowing such measurements to have greater influence in the correction model. Such threshold-based decision making merely represents a well-known quality control technique that prevent insignificant overlay measurements form unnecessarily affecting the resulting correction model while allowing larger overlay deviations to receive greater consideration. Accordingly, claim 2 would have been obvious over Adel in view of Chang.
As to claims 3 and 9, the claims recite the difference between the second weight and the first weight increase as the difference between the overlay error of the second region and the overlay error of the first region increases. As discussed, Adel teaches constructing a mathematical relationship between measured overlay values and correction values, wherein measured overlay information directly influences the resulting correction model. Chang teaches selectively utilizing different measurement data depending upon the selected field groups and measurement points in order to improve overlay correction accuracy. It would have been obvious to one of ordinary skill that, once different measurement regions are permitted to contribute differently to the mathematical correction model, increasing the weighting difference in response to increasing overlay differences merely represents a predictable optimization intended to improve correction accuracy. The claimed relationship merely defines the degree to which measurement significance changes as measurement error changes, which constitutes an obvious matter of mathematical optimization. Accordingly, claims 3 and 9 would have been obvious.
As to claims 6 and 18, the claim recites defining the weights is performed by an automatic process control (APC) system or an offline tool, and data are automatically input to the APC system while data are input to the offline tool by a user. Chang teaches that overlay correction maps are generated using computer-generated selection models and computer-readable media for overlay monitoring and control, thereby performing overlay correction using automated computer processing. Chang further teaches real-time overlay monitoring and control based upon the generated correction maps (See Figs 1A, 2A, 7A and the corresponding description). Adel likewise teaches computer-based overlay metrology, calibration, prediction, and correction processing. Utilizing an APC system or an offline analysis tool to implement the disclosed mathematical overlay correction merely represents the routine implementation of known computer-based process control techniques and would have been obvious to one of ordinary skill in semiconductor manufacturing. Accordingly, claim 6 would have been obvious.
With respect to claim 7, Adel as modified by Chang, lacks to show the first field has a plurality of unit points; the first region has one or more unit points; the second region has one or more remaining unit points and each unit point being a measurement point. However, Chang expressly discloses selecting one or more measuring points within each selected field and measuring overlay errors at the selected points (see figure 2A, 5A, 5B and the corresponding descriptions) and Adel teaches determining overlay values at different locations within a field for constructing the mathematical calibration relationship. In view of such teachings, it would be obvious to a skilled artisan that defining regions using one or more measured points merely presents an obvious subdivision of the known measurement locations disclosed by the combined references. Therefore, claim 7 would have been obvious.
As to claim 8, the claim recites the outermost unit points of the first region contact the outermost unit points of the second region. It is the Examiner’s position that once the field is partitioned into adjacent regions as discussed above, arranging adjacent boundary measurement points between neighboring regions merely represents an obvious geometric implementation dictated by the physical subdivision of the filed and does not produce any unexpected technical result. Therefore, claim 8 would have been obvious as an obvious matter of design choice.
As to claim 13, Chang expressly disclose a EUV lithographic device (see col.1, lines 30-43) wherein the performing photolithography has: applying EUV photoresist to the patterning target; exposing the EUV photoresist using the scanner and forming a photoresist pattern by developing the EUV photoresist.
Allowable Subject Matter
Claims 4, 14 and 16 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Claims 19-20 are allowed.
The following is a statement of reasons for the indication of allowable subject matter: Claims 4, 14, 16 and 19-20 have been found allowable since the prior art of record, alone or in combination, fails to teach or reasonable suggest the specifically claimed regression-based correction schemes, including the weighted regression formulations as recited in claims 4 and 14, the conditional use of the unweighted regression correction parameter as recited in claim 16 and the combination of threshold-based regional weighting and the specifically defined weighted correction parameter as recited in claims 19-20.
Prior Art Made of Record
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Huang (U.S.Pat. 12,306,546 B2); Lee et al (U.S.Pat. 11,537,042 B2) and Izikson et al (U.S.Pat. 9,620,426 B2) disclose methods and systems for overlay control and have been cited for technical background.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to HUNG HENRY NGUYEN whose telephone number is (571)272-2124. The examiner can normally be reached Monday-Friday 7:00AM-4:30PM.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Toan Minh Ton can be reached at 571-272-2303. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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HUNG HENRY NGUYEN
Primary Examiner
Art Unit 2882
Hvn
8/9/26
/HUNG V NGUYEN/ Primary Examiner, Art Unit 2882
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