DETAILED ACTION
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
1- 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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 09/24/2026 has been entered.
Amendment
2- The Request for Continued Examination amendment filed on has been entered and fully considered. Claims 16-31 remain pending in the application, where the independent claims have been amended.
Response to Arguments
3- Examiner has considered applicants’ proposed amendments, and their corresponding arguments, and acknowledges they overcome the prior art as used the 35 USC 102 rejections of the pending claims, as set forth in the final office action mailed on 7/20/2026. The above rejections have been therefore withdrawn.
4- In addition, since the Applicants’ amendments to the previously filed claims have changed the scope of the invention, this necessitated, upon further consideration, new grounds of rejections made over Shmarev in view of DeGroot et al. (US Patent No. 8248617).
Claim Rejections - 35 USC § 103
5- 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 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 of this title, 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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.
In addition, the functional recitation in the claims (e.g. "configured to" or "adapted to" or the like) that does not limit a claim limitation to a particular structure does not limit the scope of the claim. It has been held that the recitation that an element is "adapted to", "configured to", "designed to", or "operable to" perform a function is not a positive limitation but only requires the ability to so perform and may not constitute a limitation in any patentable sense. In re Hutchinson, 69 USPQ 139. (See MPEP 2111.04).
Also, it should be noted that it has been held that a recitation with respect to the manner in which a claimed device is intended to be employed does not differentiate the claimed device from a prior art apparatus satisfying the claimed structural limitations Ex-parte Masham 2 USPQ2d 1647 1987).
The claimed system in the instant application is capable of performing the claimed functionality, as is the prior art used in the present office action. The Examiner notes that where the patent office has reason to believe that a functional limitation asserted to be critical for establishing novelty in the claimed subject matter may, in fact, be an inherent characteristic of the prior art, it possesses the authority to require the applicant to prove that the subject matter shown to be in the prior art does not possess the characteristic relied on. In re Swinehart and sfiligoj, 169 USPQ 226 (C.C.P.A. 1971).
6- Claims 16-31 are rejected under 35 U.S.C. 103 as being unpatentable over Shmarev et al. WO 2016096310 in view of DeGroot et al. (US Patent No. 8248617).
As to amended claims 16, 18 and 30, Shmarev teaches an illumination arrangement, and its method of making/using, for providing at least one radiation beam for use as an illumination beam and/or reference beam in a metrology device used to measure an overlay target (Abstract, Figs. 1-14, ¶ 5-9, 51, 54-58, 69), the illumination arrangement comprising: at least one radiation beam modifier module (Figs. 4-5, 7-8, ¶ 7-8 and 54-76; OPS 510 or 710, or equivalents) configured to receive source illumination (I) and output a modified radiation beam (O) comprising a first beam component and a second beam component (components 708a-b after 745), wherein the at least one radiation beam modifier module comprises at least one path length varying arrangement (module 417-416-414 in Fig. 4, or image rotators 732x/y, with the possibility of using polarized beams, ¶ 8 and 54) configured to vary an optical path length difference between the first beam component and the second beam component by modifying an optical path length of at least one of the first beam component and the second beam component; (claim 18) wherein the at least one path length varying arrangement comprises a respective path length varying arrangement for each of the first beam component and the second beam component (Figs. 4, 7-8; one of the two beams in both embodiments has its optical path length, construed as physical path length times the refractive index of the medium in which the optical beam propagates, modified with respect to the other of the two beams), the optical path length different between the first beam component and second beam component being based on a distance along a depth direction between a first periodic structure and a second periodic structure of the overlay target (¶ 5-9, 51, 54-58, 61, 69-70, 92 for ex.; the difference between the optical path along a depth of focus is controllably selected when setting up the module to measure OV errors between patterned layers, i.e. first/second periodic structures of the overlay target).
Shmarev does not teach expressly the arrangement configured to controllably vary the optical path length difference between the first beam component and the second beam component; (Claim 30) controllably varying an optical path length of at least one of the first beam component and the second beam component, to generate an optical path length difference between the first beam component and second beam component by moving an optical delay stage in at least one direction by a first distance.
However, in a similar field of endeavor, DeGroot teaches optical apparatuses for overlay measurements (Abstract and Figs. 1-16) wherein the arrangement controllably adjusts/varies optical length differences between a test beam and a reference beam by using translation stage 150 (Fig. 1 and Col/ll. 3/27-31 and 7/21-30).
Therefore, it would have been obvious to one with ordinary skills in the art before the effective filing date of the instant application to use the apparatus/method of Fig. 4 of Shmarev in view of DeGroot’s suggestions so that the arrangement configured to controllably vary the optical path length difference between the first beam component and the second beam component; controllably varying an optical path length of at least one of the first beam component and the second beam component, to generate an optical path length difference between the first beam component and second beam component by moving an optical delay stage in at least one direction by a first distance, with the advantage of effectively and accurately optimizing the optical delay between the test beam and the reference beam.
Moreover, Shmarev teaches/suggests:
(claim 17) wherein each of the at least one radiation beam modifier module comprises: a first beam splitter (741 or 841) configured to split source illumination into the first beam component and the second beam component; and a beam combiner (745 or 845) configured to recombine the first beam component and the second beam component, subsequent to the at least one path length varying arrangement, into the modified radiation beam (Figs. 7-8).
(claim 19) wherein each of the at least one path length varying arrangement comprises an adjustable optical delay stage (Fig. 7 for ex. each image rotator adjusts the image rotation in a different direction).
(claim 20) wherein the first beam splitter and the beam combiner are physically separate elements (Fig. 7).
(claim 21) wherein the first beam splitter and the beam combiner are comprised as a single element (Fig. 8).
(claim 22) comprising: an illumination beam or reference beam splitter (741) configured to split the source illumination into two illumination beams or reference beams (708a-b); and a respective radiation beam modifier module (732x-y) for each of the two illumination beams or reference beams, configured to provide two modified radiation beams (Fig. 7).
(claim 23) wherein the distance between the first periodic structure and the second periodic structure of the overlay target is greater than a coherence length of the source illumination (See rejection of claim 16, in addition to Abstract, ¶ 5-6, 8, 58, 61, 66-37, 69-70; considering overlay error between measuring and target gratings, where the distance is necessarily larger than the coherence length of the illumination source during a measurement to avoid unnecessary optical interferences that would reduce the SNR of the measurement signals).
(claim 24) comprising at least one reference beam splitter (741) to obtain at least one reference beam (708x-y).
(claim 25) wherein the at least one reference beam includes a plurality of reference beams and each modified radiation beam is configured to include the illumination beam or one of the plurality of reference beams (the reference beam(s) produced by 510).
(claim 26) wherein at least the first beam splitter is configurable to be switched in and out of the path of the source illumination (Fig. 7; the free space set up allows the components to be displaced off/removed from the optical path of the illumination).
(claim 27) comprising an illumination source (502) configured to provide the source illumination (Fig. 5, ¶ 60).
(claim 28) A metrology apparatus comprising the illumination arrangement of claim 16 and configured to use the modified radiation beam as measurement illumination or reference illumination to measure the overlay target (See rejection of claims 16, 23, 25).
(claim 29) comprising a digital holographic microscope or a scatterometry based metrology device (¶ 53-54, 58 for ex.)
(claim 31) A lithography system comprising the metrology apparatus of claim 28 (¶ 2-4, 40-42, 50-52, 87).
Conclusion
The prior art made of record and not relied upon is considered pertinent to Applicants’ disclosure:
Optical path length (from https://en.wikipedia.org/wiki/Optical_path_length)
Bottom of Form
In optics, optical path length (OPL, denoted Λ in equations), also known as optical length or optical distance, is the vacuum length that light travels over the same time taken to travel through a given medium length. For a homogeneous medium through which the light ray propagates, it is calculated as taking the product of the geometric length of the optical path followed by light and the refractive index of the medium. For inhomogeneous optical media, the product above is generalized as a path integral as part of the ray tracing procedure. A difference in OPL between two paths is often called the optical path difference (OPD). OPL and OPD are important because they determine the phase of the light and govern interference and diffraction of light as it propagates.
In a medium of constant refractive index, n, the OPL for a path of geometrical length s is just
Relevant Prior art
US 6512588 and US 6313918 appear relevant to the use of stages and controllably control relative movement between a reference beam and test beam.
US 20040114152 and US 20030043384 appear to teach most the elements of the claimed apparatus and its method of use but fail the claimed invention as a whole
Conclusion
The examiner has pointed out particular references contained in the prior art of record in the body of this action for the convenience of the applicant. Although the specified citations are representative of the teachings in the art and are applied to the specific limitations within the individual claim, other passages and figures may apply as well. Applicant should consider the entire prior art as applicable as to the limitations of the claims. It is respectfully requested from the applicant, in preparing the response, to consider fully the entire references as potentially teaching all or part of the claimed invention, as well as the context of the passage as taught by the prior art or disclosed by the examiner.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MOHAMED K AMARA whose telephone number is (571)272-7847. The examiner can normally be reached on Monday-Friday: 9:00-17:00.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Tarifur Chowdhury can be reached on (571-272-2287. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/Mohamed K AMARA/
Primary Examiner, Art Unit 2877
