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 § 101
35 U.S.C. 101 reads as follows:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
Claims 1-20 are rejected under 35 U.S.C. 101 because the claimed invention is directed to a judicial exception (abstract idea) without significantly more.
Under Step 1 of the 2019 Revised Patent Subject Matter Eligibility Guidance, the claims are directed to a process (claim 1, a method) or a machine (claims 10 and 19, a system,), which are statutory categories.
However, evaluating claim 1, under Step 2A, Prong One, the claim is directed
to the judicial exception of an abstract idea using the grouping of a mathematical relationship/mental process. The limitations include:
collecting a plurality of measured spectrums including a spectroscopic ellipsometry (SE) Mueller spectrum matrix or two spectroscopic reflectometry (SR) spectrums from a standard wafer measured by the optical metrology tool; evaluating a performance index of the optical metrology tool, wherein the performance index is a fitting residue for a single wavelength or an area under curve (AUC) for a wavelength interval; and continuously tracking and identifying an instrumental error according to the performance index.
These limitations, under their broadest reasonable interpretation, recite an abstract idea, namely mathematical concepts and data analysis, including evaluation of mathematical relationships (e.g., residuals and integrals) and analysis of information to determine a result. Such activities fall within the category of abstract ideas identified in the 2019 Revised Patent Subject Matter Eligibility Guidance as mathematical concepts and mental processes.
Next, Step 2A, Prong Two evaluates whether additional elements of the claim “integrate the abstract idea into a practical application” in a manner that imposes a meaningful limit on the judicial exception, such that the claim is more than a drafting effort designed to monopolize the exception. The claim does not recite additional elements that integrate the judicial exception into a practical application.
Although the claim recites an “optical metrology tool” and collection of spectral data, these elements are recited at a high level of generality and merely serve as data-gathering environment for the abstract idea. The claim does not specify any technological improvement to the hardware itself or any particularized implementation that improves the operation of the metrology tool. The claim does not recite how the identified instrumental error is used to control, calibrate, or modify the operation of the optical metrology tool. Instead, the claim merely uses the metrology system as a tool to obtain and analyze data, which is insufficient to integrate the abstract idea into a practical application. See MPEP § 2106.05(g) (insignificant extra-solution activity).
Furthermore, the claimed evaluation of a performance index (residual or AUC) and identification of error constitute result-oriented functional language that does not impose meaningful limits on the abstract idea. The claim does not recite a specific technological improvement in how spectra are measured or processed, nor does it recite a specific transformation of the system based on the identified error. Accordingly, the claim is directed to an abstract idea.
At Step 2B, consideration is given to additional elements that may make the abstract idea significantly more. Under Step 2B, there are no additional elements that make the claim significantly more than the abstract idea.
The additional element, such as an optical metrology tool is well understood, routine, and conventional components in the field of optical metrology. The claim merely requires this component to perform its conventional functions of collecting and processing measurement data. The recited mathematical operations (e.g., residual calculation, AUC integration) are also well-understood and routine.
There is no indication in the claim that the combination of elements provides an unconventional technical solution or improves the functioning of the optical metrology tool itself. Instead, the claims simply apply known mathematical techniques to data obtained from a conventional measurement system. As such, the claims amount to no more than instructions to apply an abstract idea using generic and conventional components, which does not constitute significantly more under Step 2B. See MPEP § 2106.05(f).
Dependent claims 2-9 do not add anything which would render the claimed invention a patent eligible application of the abstract idea. The claims do not integrate the judicial exception into a practical application nor add significantly more under 35 U.S.C. § 101. Rather, the additional limitations fall into three categories: (i) types of input data (e.g., specifying bare-Si, isotropic, or blank wafers), which constitute mere data-gathering and thus insignificant extra-solution activity (MPEP § 2106.05(g)); (ii) mathematical relationships and physical laws (e.g., Miller matrix elements equal to 0 or 1, symmetry conditions, TE/TM equivalence, residuals based on sums of squared errors, and AUC via integration), which merely refine the abstract mathematical analysis without imposing meaningful limits (see MPEP 2106.04(a)); and (iii) generic optical metrology components (e.g., light source, polarizer, compensators, lenses, analyzer, detector), which are recited at a high level of generality and perform only well-understood, routine, and conventional functions, thereby amounting to no more than a field-of-use limitation (MPEP §2106.05(h)). None of these additional elements improve the functioning of the metrology tool, effect a transformation based on identified error, or otherwise apply the analysis in a manner that meaningfully limits the abstract idea.
Accordingly, the dependent claims, individually and in combination, fail to add an inventive concept and do not render the claims patent-eligible.
Claims 10 and 19 are rejected 35 USC § 101 for the same rationale as in claim
1.
Although the claim recites an “optical metrology” and collection of spectral data, these elements are recited at a high level of generality and merely serve as data-gathering environment for the abstract idea. The claimed “collecting”, evaluating”, and “tracking” units (claim 10), as well as the integration into an “optical metrology tool” (claim 19), are described functionally without specifying any technological improvement to the hardware itself or any particularized implementation that improves the operation of the metrology tool. The claims do not recite how the identified instrumental error is used to control, calibrate, or modify the operation of the optical metrology tool. Instead, the claims merely use the metrology system as a tool to obtain and analyze data, which is insufficient to integrate the abstract idea into a practical application. See MPEP § 2106.05(g) (insignificant extra-solution activity).
The additional elements, such as an optical metrology tool, light source, polarized, analyzer, detector, and corresponding system units, are well understood, routine, and conventional components in the field of optical metrology. The claims merely require these components to perform their conventional functions of collecting and processing measurement data. The recited mathematical operations (e.g., residual calculation, AUC integration) are also well-understood and routine.
The limitations have been considered individually and as a whole and do not amount to significantly more than the abstract idea itself.
Dependent claims 11-18 and 20, either dependent directly or indirectly from claims 10 or 19, do not add anything which would render the claimed invention a patent eligible application of the abstract idea. The claims do not integrate the judicial exception into a practical application nor add significantly more under 35 U.S.C. § 101. Rather, the additional limitations fall into three categories: (i) types of input data (e.g., specifying bare-Si, isotropic, or blank wafers), which constitute mere data-gathering and thus insignificant extra-solution activity (MPEP § 2106.05(g)); (ii) mathematical relationships and physical laws (e.g., Miller matrix elements equal to 0 or 1, symmetry conditions, TE/TM equivalence, residuals based on sums of squared errors, and AUC via integration), which merely refine the abstract mathematical analysis without imposing meaningful limits (see MPEP 2106.04(a)); and (iii) generic optical metrology components (e.g., light source, polarizer, compensators, lenses, analyzer, detector), which are recited at a high level of generality and perform only well-understood, routine, and conventional functions, thereby amounting to no more than a field-of-use limitation (MPEP §2106.05(h)). None of these additional elements improve the functioning of the metrology tool, effect a transformation based on identified error, or otherwise apply the analysis in a manner that meaningfully limits the abstract idea.
Accordingly, the dependent claims, individually and in combination, fail to add an inventive concept and do not render the claims patent-eligible.
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, 7, 9, 10, 16 and 18 are rejected under 35 U.S.C. 103 as being
unpatentable over Kwak et al. (Pub. No. US 2014/0340682) (hereinafter Kwak ) in view of Kim et al. (Pub. No. US 2016/0322267) (hereinafter Kim).
As per claims 1 and 10, Kwak teaches an instrumental error tracking and identification method for an optical metrology tool in semiconductor fabrication facility, comprising: collecting a plurality of measured spectrums including a spectroscopic ellipsometry (SE) Mueller spectrum matrix or two spectroscopic reflectometry (SR) spectrums from a standard wafer measured by the optical metrology tool (see Abstract, ¶¶ [0004]-[0005], [0012], and [0042], disclose an optical metrology system in a semiconductor fabrication environment that acquires spectral measurement (e.g., ellipsometry or reflectometry-type spectral)).
However, Kwak fails to explicitly teach evaluating a performance index of the optical metrology tool, wherein the performance index is a fitting residue for a single wavelength or an area under curve (AUC) for a wavelength interval; and continuously tracking and identifying an instrumental error according to the performance index.
Kim, however, teaches evaluating measurement quality using goodness-of-fit metrics and residual analysis, including SSE, RMSE, R-squared, and normalized goodness-of-fit, to quantify mismatch between measured spectra and model spectra (see ¶ [0047]), and further teaches application of such fitting and regression techniques in semiconductor optical metrology systems including spectroscopic ellipsometry and reflectometry (see ¶¶ [0009], [0047], [0067] and claim 6). It would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to modify the metrology performance evaluation of Kwak to utilize the explicit residual-based or goodness-of-fit performance indices of Kim, because such quantitative metrics provide a well-known and reliable measure of mismatch between measured and modeled spectral responses, thereby enabling more precise, objective, and continuous tracking and identification of instrumental error and calibration drift in the optical metrology tool.
As per claims 7 and 16, the combination of Kwak and Kim teaches the system as stated above. Kim further teaches evaluating fitting quality using sum of squared errors (SSE) and related residual metrics (see ¶ [0047]), which corresponds directly to “average sum of squared differences between measured intensities and theoretical intensities”.
As per claims 9 and 18, the combination of Kwak and Kim teaches the system as stated above. Kim further teaches spectroscopic ellipsometry/reflectometry systems, which inherently include a light source, polarizer, compensator, optics, analyzer, and detector arranged along an optical path (see ¶¶ [0053]-[0054] and claim 6). It is well known in optical metrology that calibration and error analysis may be attributed to individual components within such systems. It would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to identify instrumental error at specific components, because each component contributes to the overall optical response, thereby allowing localization and correction of faults within the metrology tool.
Claims 2-6, 8, 11-15 and 17 are rejected under 35 U.S.C. 103 as being
unpatentable over Kwak in view of Kim and further in view of Garcia-Caurel et al. (NPL: “Application of Spectroscopic Ellipsometry and Mueller Ellipsometry to Optical Characterization”, APPLIED SPECTROSCOPY OA (2012)) (hereinafter Garcia-Caurel).
As per claims 2 and 11, the combination of Kwak and Kim teaches the system as stated above except that the standard wafer is a bare-Si wafer, an isotropic wafer, or a blank wafer.
Garcia-Caurel, however, teaches using bare-Si, isotropic, or blank wafers as reference samples due to their well-defined optical response (see Abstract, page 2, third column, last paragraph and page 17, third column). It would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to incorporate Garcia-Caurel’s teaching into the combination of Kwak and Kim to utilize such wafers, because they provide predictable baseline spectra, thereby enabling more accurate detection of instrumental deviations.
As per claims 3-5 and 12-14, the combination of Kwak and Kim teaches the system as stated above except that he SE Mueller spectrum matrix includes a spectrum whose theoretical value is 0 or 1 or a constant value or includes two spectrums which are symmetry theoretically or identical theoretically.
Garcia-Caurel, however, teaches that Mueller-matrix elements are normalized by M11 and therefore exhibit constrained normalized values (see page 18, first column). Garcia-Caurel further teaches that for symmetric diffracting structures, the Mueller matrix satisfies symmetry and invariance relationships, including that the sign of the off-diagonal blocks changes under azimuth inversion while absolute values remain unchanged, and that the Mueller matrix remains invariant under 180o azimuth rotation (see page 19, first-second columns). Garcia-Caurel additionally teaches that, for special case of φ = 90o, the off-diagonal blocks become zero (seepage 19 second column). These disclosures teach Mueller-matrix spectra having theoretical zero values, normalized/constant relationships, and theoretically symmetric or identical spectra. It would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to use such known Mueller-matrix theoretical constraints in evaluating optical metrology measurements, because deviations between measured Mueller-matrix values and theoretically expected zero, normalized, or symmetric values provide a known indication of polarization distortion, calibration drift, or optical-component-induced measurement error in ellipsometry systems, thereby enabling identification and tracking of instrumental faults in optical metrology tool.
As per claims 6 and 15, the combination of Kwak and Kim teaches the system as stated above except that the SR spectrums include a transverse electric (TE) spectrum and a transverse magnetic (TM) spectrum which are identical theoretically.
Garcia-Caurel, however, defines the ellipsometric response in terms of the Fresnel reflection coefficient rp and rs for p-polarized (TM ) and s-polarized (TE) light, respectively (see page 3, column 1). Garcia-Caurel further teaches ellipsometric analysis of isotropic optical structures and teaches symmetry-constrained Mueller-matrix behavior for symmetric diffracting structures, including invariant Mueller-matrix relationships and off-diagonal Mueller-matrix elements becoming zero under specific symmetry conditions (see pages 14-15, equation (34), and page 19). It would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention that from the Fresnel-based ellipsometric formation that, under symmetric or normal-incidence isotropic conditions, the corresponding TE and TM reflection responses can become theoretically equivalent. It would have therefore been obvious to use such theoretically equivalent TE/TM spectra as baseline condition in evaluating metrology measurements, because deviations from the expected equivalence indicate polarization distortion, optical misalignment, or calibration drift, thereby enabling identification of instrumental faults.
As per claims 8 and 17, the combination of Kwak and Kim teaches the system as stated above except that the area under curve (AUC) is evaluated according to an integral operation on measured intensities.
Garcia-Caurel, however, teaches wavelength-dependent ellipsometric measurements and extracting optical characterization information from spectral ellipsometry data (see page 4, third column). However, Garcia-Caurel does not explicitly disclose evaluating an area under the curve (AUC) according to an integral operation on measured intensities. Nevertheless, it would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to compute an AUC of measured spectral intensities over a wavelength interval, because integration of intensity-versus-wavelength spectral data is a well-known mathematical operation used to summarize aggregate spectral behavior and quantify overall spectral response, thereby providing an additional performance index useful for detecting instrumental variation, calibration drift, or optical-system error.
Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Kwak
in view of Kim and further in view of Chen et al. (Patent No. US 5,581,350) (hereinafter Chen).
The combination of Kwak and Kim teaches the system as discussed above. Kim teaches optical metrology tool including ellipsometry/reflectometry optical components such as a light source, polarizer, analyzer, and detector arranged along an optical path for spectroscopic ellipsometric measurements (see claim 6 and ¶¶ [0053]-[0054]). Kwak teaches monitoring metrology-system performance by comparing measured and expected spectral responses to evaluate calibration quality, tool matching, and drift over time (see ¶ [0012]), thereby teaching tracking and monitoring framework for identifying instrument variation in an optical metrology environment. Kim further reaches evaluating spectral measurements using goodness-of-fit and residual-based metrics including SSE, RMSE, and normalized goodness-of-fit (see ¶ [0047]), corresponding to the claimed evaluating unit configured to evaluate a performance index. However, the combination of Kwak and Kim does not explicitly teach integrating the instrument-error tracking functionality into the specific optical metrology tool architecture recited in claim 19.
Chen, however, calibration and identification of optical-component-related errors within an ellipsometer, including determination of analyzer and polarizer offsets (A0 and P0) based on minimizing differences between measured and theoretical responses (see col. 9, lines 43-65). It would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to integrate the methodology monitoring framework of Kwak and the residual-based evaluation techniques of Kim into the optical metrology tool architecture of Chen, because combining known metrology calibration, spectral fitting, and optical-component diagnostic techniques would have predictably enabled real-time monitoring and identification of instrumental error within the optical metrology tool, thereby improving calibration reliability and metrology accuracy.
Claim 20 is rejected under 35 U.S.C. 103 as being unpatentable over Kwak
in view of Kim and further in view of Chen and Garcia-Caurel.
The combination of Kwak, Kim and Chen teach the system as discussed above. Garcia-Caurel further teaches Fresnel-based ellipsometric analysis using the reflection coefficients rp and rs for p-polarized and s-polarized light, respectively (see page 3), and further teaches symmetry-constrained Mueller-matrix behavior for symmetric optical structures, including invariant Mueller-matrix relationships and off-diagonal Mueller-matrix elements becoming zero under particular symmetry conditions (see page 19). It would have been obvious to one having ordinary skill in the art from these teachings that the optical response measured by the ellipsometry system depends on the combined behavior of the optical-path components, including the light source, polarizers, compensators, lenses, analyzer, and detector. It would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to extend the component-level calibration/error-identification techniques of Chen to additional optical-path components recited in claim 20, because deviations between measured spectral responses and theoretically expected polarization relationships provide known indicators of polarization distortion, optical misalignment , or calibration drift attributable to optical-system components, thereby enabling identification and tracking of instrumental faults across the optical metrology tool.
Prior art
The prior art made record and not relied upon is considered pertinent to applicant’s
disclosure:
Di et al. [‘191] discloses methods and systems for measuring values of one or more parameters of interest, including changes in values of one or more parameters of interest, based on measured spectral differences are presented herein. A trained spectral difference-based measurement model determines changes in the values of one or more parameters of interest based on a measure of differences in spectra measured before and after one or more process steps. In some examples, a measure of spectral difference is determined based on a difference in measured intensity, a difference in harmonic signal values, or a difference in value of one or more Mueller Matrix elements. A measure of spectral difference may be expressed as a set of difference values, a scalar value, or coefficients of a functional fit to difference values. A measure of spectral difference may be determined based on a weighting of spectral differences according to wavelength.
Lin et al. [‘941] discloses methods and systems for calibrating simulated measurement signals generated by a parametric measurement model are described herein. Regression on real measurement signals is performed using a parametric model. The residual fitting error between the real measurement signals and simulated measurement signals generated by the parametric model characterizes the error of the parametric model at each set of estimated values of the one or more floating parameters. Simulated measurement signals are generated by the parametric model at specified values of the floating parameters. A residual fitting error associated with the simulated measurement signals generated at the specified values of the floating parameters is derived from the residual fitting errors calculated by the regression on the real measurement signals. The simulated measurement signals are calibrated by adding the residual fitting error to the uncalibrated, simulated measurement signals. The calibrated, simulated measurement signals improve the accuracy of measurements and measurement recipe development.
Adel et al. [‘198] discloses a method for determining an overlay error between at least two layers in a multiple layer sample. An imaging optical system is used to measure multiple measured optical signals from multiple periodic targets on the sample, and the targets each have a first structure in a first layer and a second structure in a second layer. There are predefined offsets between the first and second structures A scatterometry overlay technique is used to analyze the measured optical signals of the periodic targets and the predefined offsets of the first and second structures of the periodic targets to thereby determine an overlay error between the first and second structures of the periodic targets. The scatterometry overlay technique is a phase-based technique, and the imaging optical system is configured to have an illumination and/or collection numerical aperture (NA) and/or spectral band selected so that a specific diffraction order is collected and measured for the plurality of measured optical signals. In one aspect, the number of periodic targets equals half the number of unknown parameters.
Contact information
Any inquiry concerning this communication or earlier communications from the
examiner should be directed to MOHAMED CHARIOUI whose telephone number is (571)272-2213. The examiner can normally be reached Monday through Friday, from 9 am to 6 pm.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Andrew Schechter can be reached on (571) 272-2302. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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Mohamed Charioui
/MOHAMED CHARIOUI/Primary Examiner, Art Unit 2857
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