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 .
Election/Restrictions
Applicant’s election without traverse of Group I (claims 1-18 and 27-33) and Species Groups B (claims 10, 11, and 27-33) and D (claim 29) in the reply filed on 10/22/2025 is acknowledged. However, it appears that the applicant’s response contains an inconsistency: claims 10 and 11 are identified as both elected (Group B) and withdrawn (amendment dated 10/22/2025). For the purpose of compact prosecution, the Examiner will treat claims 10 and 11 as being withdrawn in error.
Status of the Application
Claims 1-18, and 27-33 remain pending in this application. Acknowledgement is made of the amendment received 10/22/2025. Claims 19-26 are canceled, and claims 9 and 28 are withdrawn.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 2 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 2 recites the limitation "the dielectric barrier" in line 1. There is insufficient antecedent basis for this limitation in the claim. For the purpose of compact prosecution, the Examiner interprets this to mean “the lower dielectric barrier”.
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 1-4, 7, 8, 10-18, 27, and 29-33 are rejected under 35 U.S.C. 103 as being unpatentable over Akselrod et al (US 20190301025 A1, as cited in IDS dated 07/12/2023, hereafter Akselrod).
Regarding claim 1, Akselrod teaches: A method for fabricating an optical metasurface (Akselrod 100, ¶0004, 0007, 0039-0044, figs 1B, 6A-I), comprising: forming a reflective backplane structure (Akselrod 104, ¶0056-0058, “reflects optical waves”, fig 2, 3) to include:
a lower copper layer (Akselrod 614, ¶0088, fig 6D) deposited within a dielectric substrate (Akselrod 602, 610, ¶0084, fig 6D), and
a lower barrier layer (Akselrod 612, ¶0086, “barrier material”, claim 1, “a conducting or dielectric barrier layer”) between the lower copper layer and the dielectric substrate (Akselrod fig 6D);
forming an optically transparent dielectric spacer layer (Akselrod 618, ¶0089-0091, fig 6E, SiN, “SiCN, SiC, Al.sub.2O.sub.3, HfO.sub.2, SiO.sub.2 … optically transparent“) over the reflective backplane structure (Akselrod fig 6E);
forming an upper copper layer (Akselrod 622, ¶0091, 0096, fig 6F) with an upper barrier layer (Akselrod 620, ¶0091, fig 6F) over the dielectric spacer layer (Akselrod fig 6F) by a damascene process (Akselrod ¶0044-0045, 0091, “damascene process”), wherein the upper copper layer comprises a plurality of nano-gaps (Akselrod, 623, ¶0091 “formed with nano-gaps in between”) vertically extending from the dielectric spacer layer (Akselrod fig 6F), wherein the plurality of nano-gaps is filled with a dielectric fill material (Akselrod 624, ¶0091, “fills the space in the nano-gaps”), wherein the upper barrier layer is between the upper copper layer and the dielectric spacer layer (Akselrod fig 6F), and also between the upper copper layer and the dielectric fill material (Akselrod fig 6F);
removing the dielectric fill material and a portion of the upper barrier layer to expose the portions in the nano-gaps of the upper copper layer (Akselrod ¶0098-0099, fig 6G);
depositing a dielectric coating layer (Akselrod 625, ¶0100-0101, fig 6H) over a top portion and exposed side portions of the upper copper layer to form a protected upper copper layer (Akselrod fig 6H); and
filling the nano-gaps with an electrically tunable dielectric material (Akselrod 626, ¶0102-0103)(Akselrod fig 6I) that has an electrically tunable refractive index (Akselrod ¶0048, “electrically-tunable material has a refractive index that can be tuned by applying an electric voltage”).
Akselrod does not explicitly teach: a lower dielectric barrier layer.
Akselrod further teaches: a dielectric barrier layer (Akselrod 620) between a copper layer (Akselrod 622) and a dielectric substrate (Akselrod 602, 610, 618)(Akselrod fig 6F).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the lower barrier layer of Akselrod to include a dielectric material, in order to reduce absorption of optical light by the lower barrier layer, thereby improving metasurface efficiency (Akselrod ¶0105).
Further, the substitution of a dielectric barrier for liner 612 represents a simple substitution of one known element for another to obtain predicable results. MPEP 2143(I)(B). Akselrod claims 1 and 21 recite “conducting or dielectric barrier layer” as alternatives in optical metasurface fabrication, establishing that both were known in the art to perform the same function of preventing copper diffusion. A person of ordinary skill in the art would have found it obvious to select the dielectric barrier option because Akselrod recognizes that Ta/TaN barriers are “very absorptive to optical light” and cause “very low or nearly zero efficiency” (Akselrod ¶0105), whereas dielectric barrier maintain optical transparency (Akselrod ¶0091).
Regarding claim 2, Akselrod teaches: The method of claim 1, wherein the dielectric barrier layer (as best understood to mean “the lower dielectric barrier layer”, Akselrod 612 as modified by 620) operates to prevent copper diffusion into the dielectric substrate (Akselrod 602, 610)(Akselrod ¶0081, “barrier layer can reduce copper diffusivity … isolates the copper from the dielectric insulator”, ¶0091, “barriers to copper diffusion”).
Regarding claim 3, Akselrod teaches: The method of claim 1, wherein the lower dielectric barrier layer (Akselrod 612 as modified by 620) comprises one or more of SiN, SiC, SiCN, AL2O3, HfO2, and SiO2 (Akselrod ¶0091, “SiN … SiCN … SiC … AL2O3, HfO2 … SiO2”).
Regarding claim 4, Akselrod teaches: The method of claim 1, wherein the dielectric coating layer (Akselrod 625) comprises one or more of SiN, SiC, SiCN, AL2O3, HfO2, and SiO2 (Akselrod ¶0101, “SiN, SiCN, SiC, AL2O3, HfO2, SiO2).
Regarding claim 7, Akselrod teaches: The method of claim 1, wherein the dielectric spacer layer (Akselrod 618) comprises a plurality of optically transparent dielectric layers (Akselrod ¶0090-0091, “a plurality of dielectric layers … dielectric material, such as SiN, SiCN, SiC, AL2O3, HfO2, SiO2”, ¶0091, “optically transparent … dielectric material, such as SiN, SiCN, SiC, AL2O3, HfO2, SiO2”).
Regarding claim 8, Akselrod teaches: The method of claim 1, wherein the dielectric spacer layer (Akselrod 618) comprises a low-k dielectric layer (Akselrod claim 14, “dielectric spacer comprises at least … at least a thick low-k dielectric layer”).
Regarding claim 10, Akselrod, in at least one embodiment, teaches: The method of claim 1 wherein the upper barrier layer (Akselrod 720) is a conductive barrier layer (Akselrod ¶0106, “conducting barrier layer 720”).
Regarding claim 11, Akselrod teaches: The method of claim 10, wherein the upper barrier layer (Akselrod 720) comprises one or more of tantalum (Ta), tantalum nitride (TaN), and titanium nitride (TiN)(Akselrod ¶0106, “Ta and/or TaN”).
Regarding claim 12, Akselrod teaches: The method of claim 1, wherein the tunable dielectric material (Akselrod 626) comprises one or more of liquid crystal, an electro-optic polymer, a chalcogenide glass, and a semiconductor material (Akselrod ¶0048, “liquid crystals, Electro-optic (EO) polymer material, or Chalcogenide Glasses”).
Regarding claim 13, Akselrod teaches: The method of claim 1, further comprising: encapsulating the tunable dielectric material (Akselrod 626) with one or more of glass, a polymer, and sapphire (Akselrod ¶0104, “encapsulating the electrically-tunable material with an optically transparent material, such as glasses and polymers”).
Regarding claim 14, Akselrod teaches: The method of claim 1, wherein the upper copper layer (Akselrod 622) comprises a plurality of copper pillars vertically extending from the dielectric spacer layer (Akselrod 618)(Akselrod 622, ¶0091, fig 6F).
Regarding claim 15, Akselrod teaches: The method of claim 14, wherein the plurality of copper pillars (pillars comprising Akselrod 622) comprises a two-dimensional array of copper pillars (Akselrod ¶0040, “two-dimensional (2D) array … includes a pair of metal pillars”).
Regarding claim 16, Akselrod teaches: The method of claim 14, wherein the plurality of copper pillars (pillars comprising Akselrod 622) comprises a one-dimensional array of elongated copper rails. (Akselrod ¶0040, “one-dimensional (1D) array”, 0052, “columns of metallic holographic elements 106 arranged linearly on a wafer”, fig 1B).
Regarding claim 17, Akselrod, in at least one embodiment, teaches: The method of claim 14, wherein the lower copper layer (Akselrod 704) comprises copper patches (Akselrod 704, ¶0106) positioned under the nano-gaps (Akselrod 728, ¶0108) between adjacent copper pillars (pillars comprising Akselrod 718, ¶0108) of the upper copper layer (Akselrod 718)(Akselrod fig 7A-D).
Regarding claim 18, Akselrod teaches: The method of claim 17, wherein the copper patches (Akselrod 704) have a width corresponding to a pitch of the adjacent copper pillars (pillars comprising Akselrod 718) of the upper copper layer (Akselrod 718)(Akselrod claim 17, fig 7D).
Regarding claim 27, Akselrod, in at least one embodiment, teaches: A method for fabricating an optical metasurface (Akselrod 100, ¶0004, 0007, 0039-0044, 0083-0109, figs 1B, 6A-I, 7A-D), comprising:
forming an optically reflective metallic layer (Akselrod 104, ¶0056-0058, “reflects optical waves”, fig 2, 3, at least comprises a metal, copper) by:
etching a first dielectric layer (Akselrod 610) to form a first plurality of trenches (Akselrod 609, ¶0085) in the dielectric layer (Akselrod fig 6B, ¶0085),
depositing a barrier layer (Akselrod 612, ¶0086, “barrier material”, claim 1, “a conducting or dielectric barrier layer”) within the first plurality of trenches (Akselrod fig 6D, 7A, ¶0086), wherein the barrier layer operates to prevent metallic diffusion (Akselrod ¶0046, 0081, “prevents copper from diffusion”) or corrosion;
depositing a reflective metal (Akselrod 614, ¶0053, 0057) on top of the barrier layer within the first plurality of trenches to fill each of the first plurality of trenches (Akselrod fig 6D);
depositing an optically transparent dielectric spacer layer (Akselrod 618, ¶0089-0091, fig 6E, SiN, “SiCN, SiC, Al.sub.2O.sub.3, HfO.sub.2, SiO.sub.2 … optically transparent“) over the optically reflective metallic layer (Akselrod fig 6E);
depositing a dielectric etch layer (Akselrod 624) over the dielectric spacer layer (Akselrod ¶0091, fig 6F); and
forming an array of metallic holographic elements (Akselrod 106/102 ¶0039-0044) by:
etching the dielectric etch layer to form a second plurality of trenches (Akselrod 621) in the dielectric etch layer (Akselrod ¶0091, 0094, fig 6F, 7A),
depositing a conductive barrier layer (Akselrod 720, ¶0106, “conducting barrier layer 720”) within the second plurality of trenches (Akselrod ¶0091, fig 6F),
wherein the conductive barrier layer operates to prevent metallic diffusion (Akselrod ¶0046, 0081, “prevents copper from diffusion”) or corrosion,
depositing a conductive metal (Akselrod 622) on top of the conductive barrier layer (Akselrod ¶0091) within the second plurality of trenches to fill each of the second plurality of trenches (Akselrod fig 6F),
removing the dielectric etch layer and the conductive barrier layer between adjacent trenches (Akselrod ¶0098-0099, fig 6G) in the second plurality of trenches to form a plurality of nano-gaps (Akselrod, 623, ¶0091 “formed with nano-gaps in between”) between exposed metal pillars (Akselrod fig 6F),
depositing a dielectric coating layer (Akselrod 625, ¶0100-0101, fig 6H) over a top portion and exposed side portions of the exposed metal pillars to form protected metal pillars (Akselrod fig 6H), and
filling the nano-gaps with an electrically tunable dielectric material (Akselrod 626, ¶0102-0103)(Akselrod fig 6I) that has an electrically tunable refractive index (Akselrod ¶0048, “electrically-tunable material has a refractive index that can be tuned by applying an electric voltage”).
Akselrod does not explicitly teach: a dielectric barrier layer.
Akselrod further teaches: a dielectric barrier layer (Akselrod 620) between a copper layer (Akselrod 622) and a dielectric substrate (Akselrod 602, 610, 618)(Akselrod fig 6F).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the barrier layer of Akselrod to include a dielectric material, in order to reduce absorption of optical light by the barrier layer, thereby improving metasurface efficiency (Akselrod ¶0105).
Further, the substitution of a dielectric barrier for liner 612 represents a simple substitution of one known element for another to obtain predicable results. MPEP 2143(I)(B). Akselrod claims 1 and 21 recite “conducting or dielectric barrier layer” as alternatives in optical metasurface fabrication, establishing that both were known in the art to perform the same function of preventing copper diffusion. A person of ordinary skill in the art would have found it obvious to select the dielectric barrier option because Akselrod recognizes that Ta/TaN barriers are “very absorptive to optical light” and cause “very low or nearly zero efficiency” (Akselrod ¶0105), whereas dielectric barrier maintain optical transparency (Akselrod ¶0091).
Regarding claim 29, Akselrod teaches: The method of claim 27, wherein the dielectric barrier layer (Akselrod 612 as modified by Akselrod 620) is optically reflective (Akselrod ¶0091, “SiN … SiCN … SiC … AL2O3, HfO2 … SiO2”, similarly the Applicant discloses suitable materials for a dielectric barrier layer includes “SiN, SiC, SiCN, AL2O3, HfO2, and SiO2”, spec ¶0065-0066, therefore must have the same properties, including being “optically reflective.” see MPEP 2112.01).
Regarding claim 30, Akselrod teaches: The method of claim 27, wherein the reflective metal (Akselrod 614) comprises copper (Akselrod ¶0088).
Regarding claim 31, Akselrod teaches: The method of claim 27, wherein the conductive metal (Akselrod 622) comprises copper (Akselrod ¶0091, 0106).
Regarding claim 32, Akselrod teaches: The method of claim 27, wherein the conductive metal (Akselrod 622) comprises copper (Akselrod ¶0091, 0106) and wherein depositing the copper comprises:
depositing a copper seed layer on at least a base wall and sidewalls of each of the second plurality of trenches (Akselrod ¶0087), and
depositing copper to fill any remaining volume in each of the second plurality of trenches using an electrochemical plating (ECP) process (Akselrod ¶0087).
Regarding claim 33, Akselrod teaches: The method of claim 27, wherein the conductive barrier layer (Akselrod 720) comprises one of tantalum (Ta), tantalum nitride (TaN), and titanium nitride (TiN)(Akselrod ¶0106, “Ta and/or TaN”).
Claims 5 and 6 are rejected under 35 U.S.C. 103 as being unpatentable over Akselrod et al (US 20190301025 A1, as cited in IDS dated 07/12/2023, hereafter Akselrod) as applied to claim 1 above, and further in view of Shahrestani et al (US 20250216590 A1, here after Shahrestani).
Regarding claim 5, Akselrod teaches: The method of claim 1.
Akselrod does not teach: prior to filling the nano-gaps with the electrically tunable dielectric material, depositing an optically reflective metal coating layer over the dielectric coating layer.
Shahrestani, in the same field of endeavor of semiconductor device manufacturing, teaches: depositing an optically reflective metal coating layer (Shahrestani 113, ¶0101, 0065, “silver”, similarly the Applicant discloses suitable materials for an optically reflective metal coating layer includes “silver”, spec ¶0036, therefore must have the same properties, including being “optically reflective.” see MPEP 2112.01) over a dielectric nanostructure (Shahrestani 112, ¶0087)(Shahrestani ¶0087).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to modify the method of Akselrod to include “depositing an optically reflective metal coating layer over the dielectric coating layer”, prior to filling the nano-gaps, as taught by Shahrestani, in order to enable plasmonic resonances for additional spectral control and/or turning capabilities for the optical metasurface (Shahrestani ¶0105), and/or in order to improve a reflectivity of a pillar surface while maintaining electrical isolation between adjacent pillars (Akselrod ¶0057, 0092).
Regarding claim 6, Akselrod in view of Shahrestani teaches: The method of claim 5, wherein the optically reflective metal coating layer (Akselrod as modified to include Shahrestani 113) comprises silver (Shahrestani ¶0065, 0101, “silver”).
Conclusion
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/NICHOLAS B. MICHAUD/
EXAMINER
Art Unit 2818
/Mounir S Amer/Primary Examiner, Art Unit 2818