DETAILED ACTION
FOURIER FILTERING OF SPECTRAL DATA FOR MEASURING LAYER
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
The amendment filed 10-21-2025 has been entered. Claims 1-4,6,9-14,16-20 are currently pending and have been examined. Applicant’s amendment overcome 101 rejection previously set forth in the Final Office action mailed 04-22-2025. The previous rejection has been updated due to applicant’s amendments.
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 10-21-2025 has been entered.
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.
Claim(s) 1-4,6,9-14,16-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Seo (US20180156604A1) in view of Suehira (US20100007894A1).
Regarding claim 1, Seo teaches polishing the layer on the wafer using the CMP process (para 0003,0006,0018,0040);
monitoring the wafer during the CMP process with an in-situ spectrographic monitoring system (150, figure 2) to generate spectral data reflected from the wafer (para 0019,0020,0040); identifying a frequency range corresponding to the layer on the wafer (para 0043, 0057-0058); matching spectral data (S”’, figures 5-6; para 0047-0060) to a reference spectral data (Sg”’, figures 5-6; para 0047-0060), wherein the reference spectral data is associated with a thickness of the layer (para 0048-0049,0054,0058) ; and operating the CMP process based on the thickness of the layer reference spectral data until the layer on the wafer reaches a target thickness. (para 0045-0058)
Seo fails to teach applying a bandpass filter operation to the spectral data to generate filtered spectral data, wherein the bandpass filter is configured to pass the frequency range corresponding to the layer on the wafer and to reject frequencies corresponding to patterned features on the wafer or layers below the layer on the wafer, matching the filtered spectral data to a reference filtered spectral data, wherein the reference filtered spectral data has been filtered using the bandpass filter operation, and the reference filtered spectral data is associated with a thickness of the layer; and operating the CMP process based on the reference filtered spectral data until the layer on the wafer reaches a target thickness.
Suehira discloses an image measuring method for an apparatus that measures a multilayer structure by using optical-coherence optical system that includes applying a bandpass filter operation to the spectral data to generate filtered spectral data, wherein the bandpass filter is configured to pass the frequency range corresponding to the layer on the wafer and to reject frequencies corresponding to patterned features on the wafer or layers below the layer on the wafer (para 0008, para 0029-0031,0039,0065-0066,0080; figure 3b-3d).
It would have been obvious to one of ordinary skill in the art before effective filing date of the claimed invention to have modified Seo to include applying a bandpass filter operation to the spectral data. This modification would improve the measuring precision of layers. (see Suehira abstract, para 0065-0066).
Further, Seo as modified by Suehira would disclose applying a bandpass filter (see Suehira para 0008, para 0029-0031,0039,0065-0066,0080; figure 3b-3d) operation to the spectral data to generate filtered spectral data, wherein the bandpass filter is configured to pass the frequency range corresponding to the layer on the wafer and to reject frequencies corresponding to patterned features on the wafer or layers below the layer on the wafer, matching the filtered spectral data (see Seo S”’, figures 5-6; para 0047-0060 and see Suehira para 0008, para 0029-0031,0039,0065-0066,0080; figure 3b-3d) to a reference filtered spectral data (see Seo Sg”’, figures 5-6; para 0047-0060 and see Suehira para 0008, para 0029-0031,0039,0065-0066,0080; figure 3b-3d), wherein the reference filtered spectral data has been filtered using the bandpass filter operation (see Suehira para 0008, para 0029-0031,0039,0065-0066,0080; figure 3b-3d), and the reference filtered spectral data is associated with a thickness of the layer; and operating the CMP process (see Seo para 0045-0058) based on the reference filtered spectral data until the layer on the wafer reaches a target thickness.
Regarding claim 2, modified Seo teaches generating a plurality of reference filtered spectral data by simulating a model corresponding to the wafer. (see Seo para 0027- 0036 and see Suehira para 0058-0059,0099-0101)
Regarding claim 3, modified Seo teaches wherein matching the filtered spectral data to the reference filtered spectral data (see Seo para 0042-0058) comprises:
calculating a similarity between the filtered spectral data and each of the plurality of reference filtered spectral data to identify the reference filtered spectral data as the most similar to the filtered spectral data (see Seo para 0042-0058).
Regarding claim 4, modified Seo teaches wherein the model corresponding to the wafer comprises a simplified model that removes patterned features and/or layers below the layer on the wafer. (see Seo para 0058-0059,0065-0068)
Regarding claim 6, modified Seo teaches the reference filtered spectral data is derived from spectral data measurements and thickness measurements from a setup wafer. (see Seo para 0027- 0036 and see Suehira para 0058-0059,0099-0101)
Regarding claim 9, modified Seo teaches converting the spectral data into wavenumber space to generate wavenumber data
representing a number of in-layer waves in the layer, wherein the wavenumber space depends on a wavelength-dependent refractive index of the layer for each data point in the spectral data. (see Suehira abstract, para 0010-0013,0060-0071,0084)
Regarding claim 10, modified Seo teaches interpolating the wavenumber data onto an evenly spaced distribution of wavenumber values. (see Suehira para 0057)
Regarding claim 11, modified Seo teaches wherein the evenly spaced distribution of wavenumber values comprises a power-of-2 number of wavenumber values. (see Suehira para 0058,0080)
Regarding claim 12, modified Seo teaches further comprising: calculating a Discrete Fourier Transformer (DFT) of the wavenumber data to generate
DFT data. (see Suehira para 0058-0059,0067,0080-0085)
Regarding claim 13, modified Seo teaches identifying a window in the DFT data corresponding to an estimated thickness of the layer. (see Suehira para 0058-0059,0067,0080-0085)
Regarding claim 14, modified Seo teaches wherein applying the bandpass filter operation comprises setting values in the DFT data outside of the window to zero. (see Suehira para 0058-0059,0067,0080-0085).
Regarding claim 16, modified Seo teaches wherein the spectral data comprises a plurality of peaks that are associated with layers other than the layer on the wafer. (see Suehira para 0040,0059-0070)
Regarding claim 17, modified Seo teaches wherein applying the bandpass filter operation to the spectral data comprises: identifying a frequency corresponding to a peak associated with the layer (see Suehira para 0040,0059-0070); and
applying the bandpass filter operation to the spectral data in a wavenumber domain or a wavelength domain, wherein the bandpass filter operation is centered on the frequency corresponding to the peak. (see Suehira para 0065-0070)
Regarding claim 18, modified Seo teaches wherein applying the bandpass filter operation comprises: converting the spectral data into wavenumber space to generate wavenumber data representing a number of in-layer waves in the layer, wherein the wavenumber space depends on a wavelength-dependent refractive index of the layer for each data point in the spectral data; and
interpolating the wavenumber data onto an evenly spaced distribution of wavenumber
values. (see Suehira abstract, para 0010-0013,0057-0071,0084)
Regarding claim 19, modified Seo teaches applying the bandpass filter operation further comprises: calculating a Discrete Fourier Transformer (DFT) of the wavenumber data to generate DFT data . (see Suehira para 0058-0059,0067,0080-0085);
identifying a window in the DFT data corresponding to an estimated thickness of the layer . (see Suehira para 0058-0059,0067-0071,0080-0085); and
setting values in the DFT data outside of the window to zero.
see Suehira para 0058-0062 0067-0071,0080-0085)
Regarding claim 20, modified Seo teaches applying the bandpass filter operation further comprises: calculating an inverse DFT from the DFT data. (see Suehira para 0067-0068,0071,0080,0084)
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Kim (US20040246493A1) discloses an
Schietinger (US6654132B1) discloses optical techniques for measuring layer thicknesses.
David (US8892568B2) discloses building a library of spectra for optical monitoring.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SARAH AKYAA FORDJOUR whose telephone number is (571)272-0390. The examiner can normally be reached Monday - Thursday 9:30am - 5:30pm and Friday 6:00am-3:00pm.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Monica Carter can be reached at 571-272-4475. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/SARAH AKYAA FORDJOUR/Examiner, Art Unit 3723
/MONICA S CARTER/Supervisory Patent Examiner, Art Unit 3723
Prosecution Insights