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 .
Specification
The title of the invention is not descriptive. A new title is required that is clearly indicative of the invention to which the claims are directed.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim(s) 1-2, 5-7, 10, 12-15 and 18 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Kusunose et al. (U.S. PGPub No. 2015/0204729 A1).
As to claim 1, Kusunose discloses and shows in figure 4, a mask characterization apparatus comprising:
a light source (10) arranged to illuminate a reflective (17, reflective as shown in figure 4) or transmissive mask with light whereby mask-reflected or mask-transmitted light is generated ([0070], ll. 1-3; [0074], ll. 11-14);
an optical grating (19) arranged to convert the mask-reflected or mask-transmitted light into an interference pattern ([0077], ll. 20-45); and
an optical detector array (23) arranged to generate an interference signal by measuring the interference pattern ([0077], ll. 35-49).
As to claim 15, Kusunose discloses and shows in figure 4, a mask characterization apparatus comprising:
an extreme ultraviolet (EUV) light source (10) arranged to illuminate a reflective EUV mask (17) with EUV light whereby mask-reflected EUV light is generated ([0070], ll. 1-3; [0074], ll. 11-14);
a reflection EUV grating (19, where the grating is being taken as “EUV” in that it reflect EUV light inherently do to the EUV source 10 used) arranged to convert the mask-reflected EUV light into an interference pattern ([0077], ll. 20-45);
an optical detector array (23) arranged to measure the interference pattern ([0077], ll. 35-49); and
an electronic processor (24) programmed to determine a quality metric (phase shift amount which as explicitly disclosed when incorrect reduces resolution, as such phase shift is clearly a quality metric of the printed mask) for the reflective EUV mask by comparing the measured interference pattern with a reference interference pattern ([0004], ll. 24-34; [0078]).
As to claim 18, Kusunose discloses and shows in figure 4, a mask characterization apparatus comprising:
a light source (10) arranged to illuminate a reflective (17, reflective as shown in figure 4) or transmissive mask with light whereby mask-reflected or mask-transmitted light is generated ([0070], ll. 1-3; [0074], ll. 11-14);
an optical grating (19) arranged to convert the mask-reflected or mask-transmitted light into an interference pattern ([0077], ll. 20-45); and
an optical detector array (23) arranged to generate an interference signal by measuring the interference pattern ([0077], ll. 35-49); and
an electronic processor (24) programmed to determine a quality metric (phase shift amount which as explicitly disclosed when incorrect reduces resolution, as such phase shift is clearly a quality metric of the printed mask) for the reflective or transmissive mask based on the measured interference pattern ([0004], ll. 24-34; [0078]).
As to claim 2, Kusunose discloses and shows in figure 4, a mask characterization apparatus further comprising: an electronic processor (24) programmed to determine a quality metric (phase shift amount which as explicitly disclosed when incorrect reduces resolution, as such phase shift is clearly a quality metric of the printed mask) for the reflective or transmissive mask based on the interference signal ([0004], ll. 24-34; [0078]).
As to claim 5, Kusunose discloses a mask characterization apparatus wherein the light source comprises a coherent light source having spatial coherence effective for the interference pattern to have interference fringes at least in a central region of the interference pattern ([0076], this is implied by the use of the fringe scan method of Kusunose).
As to claim 6, Kusunose discloses a mask characterization apparatus wherein:
the reflective or transmissive mask is a reflective mask (explicitly shown in figure 4) ([0077], ll. 18-20);
the light source comprises an extreme ultraviolet (EUV) light source arranged to illuminate the reflective mask with EUV light whereby mask-reflected EUV light is generated ([0070], [0077], ll. 18-20);
the optical grating (19) is arranged to convert the mask-reflected EUV light into the interference pattern ([0077], ll. 20-45); and
the optical detector (23) is an EUV-sensitive optical detector array arranged to generate the interference signal by measuring the interference pattern [0077], ll. 35-49, as explicitly disclosed the detector 23 responds and has sensitivity to EUV light).
As to claim 7, Kusunose discloses a mask characterization apparatus wherein the EUV light source does not comprise a synchrotron ([0070], where the examiner notes that Kusunose explicitly discloses that a “synchrotron can be used”, as such it is not required and therefore the source can explicitly not comprise one as claimed).
As to claim 10, Kusunose discloses a mask characterization apparatus wherein the EUV light source comprises a laser-produced plasma (LPP) EUV light source ([0047]; where an Sn+ plasma source is a laser-produced plasma).
As to claim 12, Kusunose discloses a mask characterization apparatus wherein the light source is arranged to illuminate a reflective or transmissive mask with a single light beam (e.g. the beam is singular between optics 11 and 14; further the claim is constructed with the transitional phrase “comprising” as such explicitly the prior art includes at least a single light beam) whereby mask-reflected or mask-transmitted light is generated ([0070], ll. 1-3; [0077], ll. 20-45).
As to claim 13, Kusunose discloses a mask characterization apparatus wherein the mask characterization apparatus includes a single optical grating (19, where again the claim is constructed with the transitional phrase “comprising” as such explicitly the prior art includes at least a single grating 19) arranged to convert the mask-reflected or mask-transmitted light into the interference pattern ([0077], ll. 20-45).
As to claim 14, Kusunose disclose a mask characterization apparatus wherein the mask characterization apparatus includes a single optical grating (19, where again the claim is constructed with the transitional phrase “comprising” as such explicitly the prior art includes at least a single grating 19) ([0070], ll. 1-3; [0077], ll. 20-45).
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.
Claim(s) 3 and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Kusunose et al. in view of Lee et al (U.S. PGPub No. 2010/0001199 A1).
As to claims 3 and 19, Kusunose does disclose in ([0078]; [0096], ll. 22-28) the use/measurement of reference data and using phase shift to determine a quality metric.
Kusunose does not explicitly disclose wherein the electronic processor is programmed to determine the quality metric for the reflective or transmissive mask by comparing the interference signal with a reference interference signal for a reference reflective or transmissive mask obtained using the light source, the optical grating, and the optical detector array.
However, Lee does disclose in ([0049]) the basic concept of using a reference interference fringe pattern in EUV phase mask analysis for comparison with a measurement interference fringe pattern to determine a phase shift amount.
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Kusunose wherein the electronic processor is programmed to determine the quality metric for the reflective or transmissive mask by comparing the interference signal with a reference interference signal for a reference reflective or transmissive mask obtained using the light source, the optical grating, and the optical detector array in order to provide the advantage of increased accuracy and efficiency as using a common comparison between a reference value and a measurement value allowed for an efficient and rapid means by which one can characterize the quality of a phase mask ([0004] from Lee).
Claim(s) 4 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Kusunose et al. in view of Lee et al further in view of Ando et al. (U.S. PGPub No. 2016/0123810 A1).
As to claims 4 and 20, Kusunose in view of Lee does not explicitly disclose a mask characterization apparatus wherein the electronic processor is programmed to compare the interference signal with the reference interference signal by computing a mean squared error (MSE) between the measured interference signal and the reference interference signal.
However, Ando does disclose in ([0118]) the use of the common MSE two
dimensional image based equation (EQ5) relative to image signals. It would have been obvious to apply a known mathematical image analysis technique to interference patterns (as disclosed MSE is commonly used to compare a known (i.e. example) to a reference (i.e. comparative example)) of Kusunose in a predictable manner in order to allow efficient image analysis.
It would have been obvious to one having ordinary skill in the art before the
effective filing date of the claimed invention to modify Kusunose in view of Lee with a mask characterization apparatus wherein the electronic processor is programmed to compare the interference signal with the reference interference signal by computing a mean squared error (MSE) between the measured interference signal and the reference interference signal in order to provide the advantage of increased accuracy in using a common technique one can compare images to get a more correct answer on the differences between the two images as disclosed in Ando.
Claim(s) 8-9 and 16 are rejected under 35 U.S.C. 103 as being unpatentable over Kusunose et al. in view of Boonzajer Flaes et al. (U.S. PGPub No. 2017/0269482 A1).
As to claims 8-9 and 16, Kusunose does not explicitly disclose a mask characterization apparatus wherein the EUV light source comprises a free electron laser (FEL) source or wherein the EUV light source comprises a high harmonic generation (HHG) EUV source which outputs spatially coherent light.
However, Boonzajer Fales does disclose in ([0070], ll. 1-11) the use of both HHG and FEL sources in place of plasma sources as each being a known alternative in EUV materials under inspection.
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to modify Kusunose with a mask characterization apparatus wherein the EUV light source comprises a free electron laser (FEL) source or wherein the EUV light source comprises a high harmonic generation (HHG) EUV source which outputs spatially coherent light in order to provide the advantage of increased efficiency and expected results in using common and predictable alternative sources one can account for differing materials/layers of the sample under test and measure all based on specific needs as explicitly taught by Boonzajer Fales.
Claim(s) 11 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Kusunose et al. in view of Park et al. (U.S. Patent No. 11,635,371 B2).
As to claim 11, Kusunose does not explicitly disclose a mask characterization apparatus wherein the EUV light source further a spatial filter arranged to increase spatial coherence of the EUV light.
However, Park does disclose and show in figure 1 and in (col. 3, II. 18-24; col. 3,
I. 38-62) the basic concept of using a plasma based EUV laser light source (100) that is
filtered with a spatial filter (200, and sub-part 210) in order to output as explicitly
disclosed an improved coherent of light.
It would have been obvious to one having ordinary skill in the art before the
effective filing date of the claimed invention to modify Kusunose a mask characterization apparatus wherein the EUV light source further a spatial filter arranged to increase spatial coherence of the EUV light in order to provide the advantage of
expected results in using a common EUV configuration to provide a more spatially
coherent light to the sample under test resulting in higher quality interference fringes for
measurement.
As to claim 17, Kusunose does disclose a mask characterization apparatus wherein the EUV light source comprises a laser-produced plasma (LPP) EUV light source ([0047]; where an Sn+ plasma source is a laser-produced plasma).
Kusunose does not explicitly disclose a mask characterization apparatus wherein the EUV light source further a spatial filter arranged to increase spatial coherence of the EUV light.
However, Park does disclose and show in figure 1 and in (col. 3, II. 18-24; col. 3,
I. 38-62) the basic concept of using a plasma based EUV laser light source (100) that is
filtered with a spatial filter (200, and sub-part 210) in order to output as explicitly
disclosed an improved coherent of light.
It would have been obvious to one having ordinary skill in the art before the
effective filing date of the claimed invention to modify Kusunose a mask characterization apparatus wherein the EUV light source further a spatial filter arranged to increase spatial coherence of the EUV light in order to provide the advantage of
expected results in using a common EUV configuration to provide a more spatially
coherent light to the sample under test resulting in higher quality interference fringes for
measurement.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MICHAEL P LAPAGE whose telephone number is (571)270-3833. The examiner can normally be reached Monday-Friday 8-5:30.
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/Michael P LaPage/Primary Examiner, Art Unit 2877