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
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, 3, 6, 7, 12-14, 16, 23, and 24 are rejected under 35 U.S.C. 103 as being unpatentable over Kroyan et al. [US 2002/0048288] in view of Robles et al. [US 2004/0005089], and Finders [US 2006/0170898].
For claims 1 and 16, Kroyan teaches a computer program product (see claim 1) comprising a non-transitory computer-readable medium having method instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to perform the method, the method (see Fig. 2I) comprising:
providing an optical spectrum (laser illumination spectrum), a mask pattern (OPC), and a pupil design (OAI), that together are configured to provide a lithography system with a depth of focus (lithography results DOF);
iteratively varying the optical spectrum to provide a modified optical spectrum that increases the depth of focus (optimization of spectrum S, see Fig. 2I), wherein the optical spectrum comprises a plurality of wavelength peaks (peak separation for dual and triple peak illumination spectra, see Figs. 2E-2I and [0050]-[0054]), and wherein the iteratively varying further comprises performing the variation at least until a product of the depth of focus and an exposure latitude is increased (optimization including DOF and EL which define process window, see Figs. 2B-2D and [0042]-[0046], where there is an increase in product of EL and DOF between monochromatic and engineered polychromatic, see also Figs. 2H2 and 2I, and [0051]-[0054]); and
configuring a component of the lithography system based on the modified optical spectrum (optimized illumination added to constant process).
Kroyan teaches providing optimized lithography process inputs including optical proximity resolution, numerical aperture with fill factor, and off-axis illumination that can be used in conjunction with RELAX (see [0030] and [0053]-[0054] and Fig. 2I), but fails to explicitly teach providing a mask pattern having a sub-resolution assist feature; iteratively varying a separation distance of the assist feature from an associated main feature in the mask pattern to provide a modified mask pattern to increase the depth of focus, wherein the varying of the separation distance increase of maintains optical contrast.
Robles teaches a method (see Figs. 5A-5E) of providing a mask pattern (a photolithographic design, see [0062]) having a sub-resolution assist feature (SRAF, see [0071]); iteratively varying a separation distance of the assist feature from an associated main feature in the mask pattern to provide a modified mask pattern (spacing between the SRAF and edge or multiple SRAFs, see [0071], varying spacing through multiple loop backs, see [0074]) to increase the depth of focus (local contrast and depth of focus are directly related, and that by improving ILS it is possible to improve the depth of focus, see [0161]), wherein the varying of the separation distance increase or maintains optical contrast (improve contrast, see [0087]).
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 iterative SRAF spacing adjustment as taught by Robles in the iterative exposure optimization as taught by Kroyan, in order to identify an optimal RET approach that guarantees a stable process under focus variation based on desired illumination conditions, so that both the iterative variation of mask pattern to increase the depth of focus and contrast as taught by Robles and the iterative variation of optical spectrum to increase the depth of focus as taught by Kroyan, together in the combination, collectively provide an increased depth of focus.
Kroyan teaches a normal peak separation of at least 500 femtometers (see [0137] and claim 7, pulse to pulse adjustment, see [0048]-[0049]), but fails to explicitly teach varying the optical spectrum comprises varying a separation between at least two wavelength peaks of the plurality of wavelength peaks within a range of, or selected from, 1000 femtometers or less.
Finders teaches varying the optical spectrum comprises varying a separation between at least two wavelength peaks of the plurality of wavelength peaks within a range of, or selected from, 1000 femtometers or less (repeated varying of the separation between peaks along discrete points along the parabolic between 0 and 200 femtometers shown in Fig. 3 based on the measured pattern bias, see Figs. 3 and 4 and [0076]-[0086], the example shows all variation is within 0-1000 femtometer range, see Fig. 5).
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 variation range in the optimization of the peak separation as taught by Finders in the optimization algorithm for lithography process control as taught by Kroyan in order to apply a spectrum peak separation solution to correct for pitch dependent diffraction effects at the mask that result CD variation.
For claim 3, Kroyan teaches the optical spectrum is provided in a series of pulses, and wherein a center wavelength in at least one peak in the optical spectrum is further varied in every other pulse to shift by approximately 500 fm (two or more peaks are separated by at least 0.5 picometer, see [0137] and claim 7, pulse to pulse adjustment, see [0048]-[0049]).
For claim 6, Kroyan teaches delivering light corresponding to the spectrum by a light source, wherein multiple colors of light are delivered at different times (pulse to pulse adjustment, see [0048]-[0049]).
For claims 7 and 23, Kroyan teaches the iteratively varying further comprises iteratively varying a bandwidth of a peak in the optical spectrum (iterative spectrum optimization with bandwidth control, see [0011], [0027]-[0035], [0041]-[0042], [0050]-[0054] and Fig. 3-4C).
For claims 12 and 24, in the combination of Kroyan and Robles, Robles teaches the iteratively varying further comprises introducing a sub-resolution assist feature in the mask pattern to increase the depth of focus (SRAF placement can also be included in the iterative process, see [0071] and [0090]).
For claim 13, in the combination of Kroyan and Robles, Robles teaches the iteratively varying further comprises varying of the sub-resolution assist feature by changing a width of the sub-resolution assist feature (SRAF feature selection includes width, see [0071] and [0074]).
For claim 14, Kroyan teaches the iteratively varying further comprises performing the iteratively varying at least until a process window, based on a parameter space defined at least partly by a dose and an exposure latitude, is increased (Figs. 2B-2D and [0042]-[0045]).
Claims 2, 17, and 19-22 are rejected under 35 U.S.C. 103 as being unpatentable over Kroyan et al. [US 2002/0048288] in view of Arai et al. [US 2013/0268902], Robles et al. [US 2004/0005089], and Finders [US 2006/0170898].
For claims 2, 17, 19, and 20, Kroyan teaches a computer program product (see claim 1) comprising a non-transitory computer-readable medium having method instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to perform the method, the method (see Fig. 2I) comprising:
providing an optical spectrum (laser illumination spectrum), a mask pattern (OPC), and a pupil design (OAI), that together are configured to provide a lithography system with a depth of focus (lithography results DOF);
iteratively varying the optical spectrum to provide a modified optical spectrum that increases the depth of focus (optimization of spectrum S, see Fig. 2I), wherein the optical spectrum comprises a plurality of wavelength peaks (peak separation for dual and triple peak illumination spectra, see Figs. 2E-2I and [0050]-[0054]), wherein the iteratively varying further comprises performing the variation at least until a product of the depth of focus and an exposure latitude is increased (optimization including DOF and EL which define process window, see Figs. 2B-2D and [0042]-[0046], where there is an increase in product of EL and DOF between monochromatic and engineered polychromatic, see also Figs. 2H2 and 2I, and [0051]-[0054]); and
configuring a component of the lithography system based on the modified optical spectrum (optimized illumination added to constant process).
Kroyan teaches providing optimized lithography process inputs including optical proximity resolution, numerical aperture with fill factor, and off-axis illumination that can be used in conjunction with RELAX (see [0030] and [0053]-[0054] and Fig. 2I).
Kroyan fails to teach iteratively varying an assist feature in the mask pattern to provide a modified optical spectrum and a modified mask pattern that collectively increase the depth of focus; iteratively varying the optical spectrum and the pupil design to provide a modified optical spectrum and a modified pupil design that collectively increase the depth of focus; and configuring a component of the lithography system based on the modified optical spectrum, a modified pupil design, and the modified mask pattern that collectively increase the depth of focus, wherein the iteratively varying further comprises iteratively varying, concurrently, the optical spectrum, the mask pattern, and the pupil design to provide the modified optical spectrum, the modified mask pattern, and the modified pupil design.
Arai teaches a non-transitory computer-readable medium (see [0026]) having method instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to perform the method of iteratively varying an assist feature in the mask pattern to provide a modified mask pattern that increases the depth of focus (optimized patterns of the mask to meet evaluation function, see Fig. 1, iterative changes by step 109); iteratively vary the pupil design to provide a modified pupil design that collectively increase the depth of focus (exposure condition includes an effective light source at the pupil, see Fig.1 and [0027], iterative changes by step 109); and configuring a component of the lithography system based on the modified mask pattern that collectively increase the depth of focus (applied to the exposure apparatus, see [0036] and Figs. 5A-6D), wherein the iteratively varying further comprises iteratively varying, concurrently, the mask pattern, and the pupil design to provide the modified mask pattern and the modified pupil design (exposure condition includes an effective light source at the pupil and mask parameter value, see Fig.1).
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 optimization of the mask pattern and the pupil source to expand DOF as taught by Arai in the optimization as taught by Kroyan because optimization of the mask pattern and other exposure conditions allow for extending the depth of focus further increasing imaging performance.
Kroyan teaches providing optimized lithography process inputs including optical proximity resolution, numerical aperture with fill factor, and off-axis illumination that can be used in conjunction with RELAX (see [0030] and [0053]-[0054] and Fig. 2I), but fails to explicitly teach providing a mask pattern having a sub-resolution assist feature; iteratively varying a separation distance of the assist feature from an associated main feature in the mask pattern to provide a modified mask pattern to increase the depth of focus, wherein the varying of the separation distance increase of maintains optical contrast.
Robles teaches a method (see Figs. 5A-5E) of providing a mask pattern (a photolithographic design, see [0062]) having a sub-resolution assist feature (SRAF, see [0071]); iteratively varying a separation distance of the assist feature from an associated main feature in the mask pattern to provide a modified mask pattern (spacing between the SRAF and edge or multiple SRAFs, see [0071], varying spacing through multiple loop backs, see [0074]) to increase the depth of focus (local contrast and depth of focus are directly related, and that by improving ILS it is possible to improve the depth of focus, see [0161]), wherein the varying of the separation distance increase or maintains optical contrast (improve contrast, see [0087]).
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 iterative SRAF spacing adjustment as taught by Robles in the iterative exposure optimization as taught by Kroyan, in order to identify an optimal RET approach that guarantees a stable process under focus variation based on desired illumination conditions, so that both the iterative variation of mask pattern to increase the depth of focus and contrast as taught by Robles and the iterative variation of optical spectrum to increase the depth of focus as taught by Kroyan, together in the combination, collectively provide an increased depth of focus.
Kroyan teaches a normal peak separation of at least 500 femtometers (see [0137] and claim 7, pulse to pulse adjustment, see [0048]-[0049]), but fails to explicitly teach varying the optical spectrum comprises varying a separation between at least two wavelength peaks.
Finders teaches varying the optical spectrum comprises varying a separation between at least two wavelength peaks of the plurality of wavelength peaks (repeated varying of the separation between peaks along discrete points along the parabolic between 0 and 200 femtometers shown in Fig. 3 based on the measured pattern bias, see Figs. 3 and 4 and [0076]-[0086], the example shows all variation is within 0-1000 femtometer range, see Fig. 5).
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 variation range in the optimization of the peak separation as taught by Finders in the optimization algorithm for lithography process control as taught by Kroyan in order to apply a spectrum peak separation solution to correct for pitch dependent diffraction effects at the mask that result CD variation.
For claim 21, Kroyan teaches the iteratively varying further comprises iteratively varying a bandwidth of a peak in the optical spectrum (iterative spectrum optimization with bandwidth control, see [0011], [0027]-[0035], [0041]-[0042], [0050]-[0054] and Fig. 3-4C).
For claim 22, in the combination of Kroyan and Robles, Robles teaches the iteratively varying further comprises introducing a sub-resolution assist feature in the mask pattern (SRAF, see [0071]) to increase the depth of focus (local contrast and depth of focus are directly related, and that by improving ILS it is possible to improve the depth of focus, see [0161]).
Claims 9-11 are rejected under 35 U.S.C. 103 as being unpatentable over Kroyan, Robles and Finders as applied to claim 1 above, and further in view of Yuan et al. [US 2012/0252199].
For claims 9-11, Kroyan fails to teach the iteratively varying further comprises varying a main feature in the mask pattern to increase the depth of focus, wherein the main feature includes an edge location and a mask bias location, and the iteratively varying further comprises varying the edge location and/or the mask bias location, wherein two mask bias locations are symmetrically varied about a center of the main feature.
Yuan teaches the iteratively varying further comprises varying a main feature in the mask pattern to increase the depth of focus (mask bias included in iterative process, see [0026]-[0031]), wherein the main feature includes an edge location and a mask bias location, and the iteratively varying further comprises varying the edge location and/or the mask bias location (mask bias included in iterative process, see [0026]-[0031]), wherein two mask bias locations are symmetrically varied about a center of the main feature (mask biasing of edges in feature 92 to increase width to new pattern 96, see Figs. 6-9).
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 iterative variation of the mask main pattern as taught by Yuan in the optimization algorithm for lithography process control as taught by Kroyan in order to provide a target geometry that is substantially identical to the design target and an image intensity dip that is minimized.
Response to Arguments
Applicant's arguments filed on July 6, 2026 have been fully considered but they are not persuasive. The Applicant argues on pages 7-11, regarding claims 1, 16, 19, and 20, that in the combination of Kroyan and Robles there is no teaching of performing the claimed variation at least until a product of the depth of focus and an exposure latitude is increased, in particular, Kroyan fails to teach the product of any two values and Robles does not recognize maintaining optical contrast in the face of varying the optical spectrum that increases the depth of focus.
The Examiner respectfully disagrees. Kroyan teaches in Fig. 2I that the depth of focus (DOF) and the exposure latitude (EL) are results that are relied upon to determine the need for further optimization in the iterative process. Fig. 2D and paragraphs [0042]-[0045] teaches the engineered polychromatic process window area is increased relative to the conventional spectra when forming contact hole patterns. Further, in paragraphs [0046] and [0052] and Fig. 2H2 teaches improvement in the overall process window area through tuning of the optimization process. In both cases the area of the process window is a measure of the product between the EL and the DOF. None of the claims 1, 16, 19, and 20 recite any limitation that includes performing a calculation of the product or how the computation may be performed. Only that it is the case that the product is increased. Kroyan teaches that spectral change variation results in a change in the DOF and the EL, where the DOF increases at a rate faster than a reduction rate of the EL. Fig. 2D shows the change in spectrum where the product of the Monochromatic process window boundary points (approx. 20% EL and 0.5 um DOF) is less than the product of the Polychromatic process window boundary points (approx. 10% EL and 1.4 um DOF), thereby teaching the Polychromic product increases relative to the Monochromatic product. In the iterative process taught in Fig. 2I, spectrum optimization results in an increase in the product of the EL and that DOF for at least a contact hole pattern as shown in Fig. 2D.
Kroyan teaches in paragraph [0052] minimization of contrast loss. Robles teaches in paragraph [0116] that contrast optimization can be performed such that process window area is increased. Accordingly, in the combination, Kroyan teaches that spectrum can be changed to adjust process window area to increase DOF and minimize contrast loss and Robles teaches adjusting the mask pattern sub-resolution assist features to optimize a contrast increase while further increasing the process window area.
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Steven H Whitesell whose telephone number is (571)270-3942. The examiner can normally be reached Mon - Fri 9:00 AM - 5:30 PM (MST).
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, Curt Mayes can be reached at 571-272-1234. 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.
/Steven H Whitesell/ Primary Examiner, Art Unit 1759
Prosecution Insights