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
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, 2, 4-6, 8 and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Kumar (US 5,399,238 B1) in view of Hill (US 20190108963 A1).
Regarding claim 1, Kumar teaches an emitter configured to emit electrons, the emitter comprising:
A body (base material 44) having a point (fig. 2E);
A metal layer (adhesion layer 68) of a first metal on at least the point (adhesion layer 16 may be formed of metal such as titanium, col. 5 lines 27-31; layer 68 is similar to layer 16, col. 8 lines 28-29); and
An electron source layer (low work-function material 60) on the metal layer,
Wherein the point comprises a second metal (Cu, col. 7 line 65) other than the first metal.
Kumar does not teach that the electron source layer comprises graphene.
Hill teaches an electron emitter having an electron source layer comprising graphene ([0022, 0051]).
It would have been obvious to one of ordinary skill in the art at the time of the invention to select graphene as the low-work function layer in the electron emitter of Kumar, based on the teaching of Hill that this is an appropriate electron emitter layer for use in an electron source which has high brightness ([0074]) and low chemical sensitivity ([0108]).
Regarding claim 2, Kumar teaches that the second metal (titanium) has a higher melting point than the first metal (copper), and the first metal and the second metal are configured to alloy (i.e. they are next to each other and capable of alloying).
Regarding claim 4, Kumar teaches that the second metal may be a refractory metal (tantalum, col. 5 lines 27-31).
Regarding claim 5, Kumar teaches that the second metal is titanium.
Regarding claim 6, Kumar teaches that the first metal is copper.
Regarding claim 8, Kumar teaches that the metal layer and the electron source layer are concentric layers on at least part of a surface of the body (fig. 2E).
Regarding claim 10, Kumar (as modified by Hill, above) teaches an electron source (field emitter device, fig. 3) comprising the emitter of claim 1.
Claims 11-12 are rejected under 35 U.S.C. 103 as being unpatentable over Kumar in view of Hill and in further view of Yasuda (US 20100019648 A1).
Regarding claim 11, Kumar and Hill teach all the limitations of claim 10 as described above. Kumar and Hill do not teach an electric field generator configured to generate an electric field at the point so as to lower a work function of the electron source layer.
Yasuda teaches an electron emitter having an electric field generator (“applying a strong electric field to front end portion of the electron source”, [0099]; implicitly some generator must exist) to generate an electric field at the point of the emitter so as to lower the work function of the front end ([0099]).
It would have been obvious to one of ordinary skill in the art on or before the effective filing date of the current claims to modify the system of Kumar and Hill to have the electric field generator for lowering a work function taught by Yasuda, in order to more easily extract electrons and increase the beam luminance (which inversely depends on the work function) with no unexpected result.
Regarding claim 12, Yasuda teaches an electrically conductive suppressor (24, fig. 2) comprising a hole through which the body extends such that the point is exposed, wherein the suppressor is configured to reduce emission of electrons from parts of the emitter other than the point ([0097]).
It would have been obvious to one of ordinary skill in the art on or before the effective filing date of the current claims to modify the system of Kumar and Hill to have the suppressor electrode taught by Yasuda, in order to prevent unwanted emission of electrons from side surfaces of the emitter.
Claims 13-16 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Kumar in view of Hill and in further view of Frosien (US 20060151711 A1).
Regarding claim 13, Kumar and Hill teach all the limitations of claim 10 as described above. Kumar and Hill do not teach an illumination apparatus comprising the electron source of claim 10.
Frosien teaches an illumination apparatus (charged beam column of inspection system 900, fig. 14) having a pointed field emitter electron source (132).
It would have been obvious to one of ordinary skill in the art on or before the effective filing date of the current claims to use the electron emitter of Kumar (as modified by Hill) in the inspection device of Frosien, as a matter of substituting a known effective electron source with a similar tip shape and configuration (i.e. a row of pointed tips) to that taught by Frosien, and which could be expected to function equivalently in producing multiple beams for a charged particle inspection system.
Regarding claim 14, Frosien teaches an aperture plate (41, fig. 14) comprising an aperture.
Regarding claim 15, Frosien teaches an electron beam inspection apparatus (900) comprising the illumination apparatus of claim 13.
Regarding claim 16, Kumar teaches an electron source comprising emitter configured to emit electrons, the emitter comprising:
A body (base material 44) having a point (fig. 2E);
A metal layer (adhesion layer 68) on at least the point (adhesion layer 16 may be formed of metal such as titanium, col. 5 lines 27-31; layer 68 is similar to layer 16, col. 8 lines 28-29); and
An electron source layer (low work-function material 60) on the metal layer,
Wherein the point comprises a different metal (Cu, col. 7 line 65) from the metal layer.
Kumar does not teach that the electron source layer comprises graphene.
Hill teaches an electron emitter having an electron source layer comprising graphene ([0022, 0051]).
It would have been obvious to one of ordinary skill in the art at the time of the invention to select graphene as the low-work function layer in the electron emitter of Kumar, based on the teaching of Hill that this is an appropriate electron emitter layer for use in an electron source which has high brightness ([0074]) and low chemical sensitivity ([0108]).
Kumar and Hill do not teach an illumination apparatus comprising the electron source.
Frosien teaches an illumination apparatus (charged beam column of inspection system 900, fig. 14) having a pointed field emitter electron source (132).
It would have been obvious to one of ordinary skill in the art on or before the effective filing date of the current claims to use the electron emitter of Kumar (as modified by Hill) in the inspection device of Frosien, as a matter of substituting a known effective electron source with multiple field emitter tips with no unexpected result.
Regarding claim 18, Frosien teaches an aperture plate (41, fig. 14) comprising an aperture.
Claims 1, 3, 7, 9, and 16-17 are rejected under 35 U.S.C. 103 as being unpatentable over Anazawa (US 20050212395 A1) in view of Khursheed (WO 2018217167 A1).
Regarding claim 1, Anazawa teaches an emitter configured to emit electrons, the emitter comprising:
A body (base body 2, fig. 1, [0094]) having a point (point filament structure, fig. 4B);
An electron source layer (carbon nanotube structure 1, fig. 1, [0092]), the electron source layer comprising graphene (carbon nanotubes comprise graphene, [0004]);
Where the point comprises a metal (tungsten, [0094], [0267]).
Anazawa does not teach a metal layer on the point, where the graphene layer is on the metal layer, comprising a different metal than the point.
Khursheed teaches that the work function of a graphene electron emission layer is lowered by placing it on a palladium, cobalt or nickel film (p. 3).
It would have been obvious to one of ordinary skill in the art on or before the effective filing date of the invention to modify the system of Anazawa to have a metal layer between the metal emitter and the graphite emission layer as taught by Khursheed, as Anazawa teaches that the system “may have any other layer” ([0192]) and one of ordinary skill in the art would be aware that adding a palladium, cobalt or nickel layer below the graphite layer would have the effect of increasing the work function of the electron emitter and produce a brighter electron beam with no unexpected result.
Regarding claim 3, Anazawa teaches that the first metal is tungsten and Khursheed teaches that the second metal is nickel, so that in the combination the first metal would have a lower remanence than the second metal.
Regarding claim 7, Khursheed teaches that the charged particle source layer is doped by the first metal (doping due to chemisorption, p. 12 line 32)
Regarding claim 9, Anazawa teaches a heating element (filament 22) configured to provide a heat load to the body to promote thermionic electronic emission (thermal-emission type electron gun, figs.3, 4A-4C, [0024-0025]).
Regarding claim 16, Anazawa teaches an illumination apparatus (electron microscope, [0002]) comprising an electron source comprising an emitter configured to emit electrons, the emitter comprising:
A body (base body 2, fig. 1, [0094]) having a point (point filament structure, fig. 4B);
An electron source layer (carbon nanotube structure 1, fig. 1, [0092]), the electron source layer comprising graphene (carbon nanotubes comprise graphene, [0004]);
Where the point comprises a metal (tungsten, [0094], [0267]).
Anazawa does not teach a metal layer on the point, where the graphene layer is on the metal layer, comprising a different metal than the point.
Khursheed teaches that the work function of a graphene electron emission layer is lowered by placing it on a palladium, cobalt or nickel film (p. 3).
It would have been obvious to one of ordinary skill in the art on or before the effective filing date of the invention to modify the system of Anazawa to have a metal layer between the metal emitter and the graphite emission layer as taught by Khursheed, as Anazawa teaches that the system “may have any other layer” ([0192]) and one of ordinary skill in the art would be aware that adding a palladium, cobalt or nickel layer below the graphite layer would have the effect of increasing the work function of the electron emitter and produce a brighter electron beam with no unexpected result. Regarding claim 17, Anaszawa teaches that the emitter comprises a heating element (filament 22) configured to apply a heat load to the body so as to promote thermionic electron emission (thermal emission-type electron gun, fig. 3, 4A-4C, [0024-0025]).
Claims 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over Anazawa in view of Yasuda and in further view of Khursheed.
Regarding claim 19, Anazawa teaches a method of emitting a beam of electrons, the method comprising:
Providing an emitter (electron-emission electrode, Abstract) configured to emit electrons, comprising an electron source layer (carbon nanotube structure 1, fig. 1) disposed on a body of the emitter, wherein the electron source layer comprises graphene (graphene in carbon nanotube layer, [0041]);
Heating the point so as to promote thermionic emission (thermal emission, [[0024]).
Anazawa does not teach heating the tip to at least 500 C.
Yasuda teaches a thermionic electron emitter in which a tip is heated to at least 500 C (1300 C, [0062]).
It would have been obvious to one of ordinary skill in the art on or before the effective filing date of the invention to heat the tip of Anazawa to the temperature taught by Yasuda, as a matter of selecting a known temperature range effective for promoting thermionic emission from a tip.
Anazawa and Yasuda do not teach a metal layer disposed on at least a point of the body of the emitter.
Khursheed teaches that the work function of a graphene electron emission layer is lowered by placing it on a palladium, cobalt or nickel film (p. 3).
It would have been obvious to one of ordinary skill in the art on or before the effective filing date of the invention to modify the system of Anazawa to have a metal layer between the metal emitter and the graphite emission layer as taught by Khursheed, as Anazawa teaches that the system “may have any other layer” ([0192]) and one of ordinary skill in the art would be aware that adding a palladium, cobalt or nickel layer below the graphite layer would have the effect of increasing the work function of the electron emitter and produce a brighter electron beam with no unexpected result.
Regarding claim 20, Anazawa (as modified by Khursheed, above) teaches that the metal layer comprises a first metal, and the point of the body comprises a second metal other than the first metal.
Response to Arguments
Applicant's arguments filed 13 July 2026 have been fully considered but they are not persuasive.
Regarding the rejection of claims 1, 2, 4-6, 8 and 10 as unpatentable over Kumar in view of Hill, it is true that a graphite layer is not contemplated by Kumar. However Hill teaches that graphene can successfully be used as an electron emission layer and it is known in the art that graphene possesses the properties necessary to be successfully substituted for the low work-function material of Kumar. Kumar teaches that the material must have a work function of less than 4.5 eV, which is a known property of some forms of graphene on metal surfaces (as seen in Giovanetti et al, “Doping Graphene With Metal Contacts”, PRL 101, 026803, 2008, Table 1, cited for reference only). One of ordinary skill in the art therefore would be motivated to substitute graphene for the emitter material of Kumar as a known low work-function material based on its art-recognized suitability for the intended use (MPEP 2144.07 [R-01.2024]). It is not clear from the disclosure of Kumar that there is any specific requirement for the material that is not met by graphene, as Kumar teaches a wide variety of possible materials (col. 5 lines 13-20). Applicant has not established that substituting graphene for the cited low-work-function material would require undue experimentation or would destroy the functionality of the device of Kumar. It is not clear that any different emission mechanism in graphene as opposed to the materials disclosed by Kumar is relevant to the current rejection, as the low-work function layer is only required to emit electrons by some mechanism to meet the limitation of the claim.
Regarding claim 2, the limitation “wherein the first metal and second metal are configured to alloy”, is interpreted to mean only that the metals are capable of alloying and the structure is arranged so that alloying is possible. The claim does not require that the metals actually form an alloy.
Regarding the rejection of claim 1 in view of Anazawa and Khursheed, the emission layer in Anazawa is a carbon nanotube device formed by coiling up graphene (which is interpreted as “comprising graphene”, i.e. it is formed of graphene; Anazawa cites a graphene layer within the carbon nanotube, [0041]). Regarding the combination with Khursheed, as stated above one of ordinary skill in the art would be motivated to add a metal layer to the system of Anazawa in order to improve the electrical emission properties of the graphene or graphene-based sheet due to adsorption of the metal. Placing a metal layer on the emitter of Anazawa is considered to be within the skill of one of ordinary skill in the art, for the purpose of improving the electron emission of the system of Anazawa with no unexpected result.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 DAVID E SMITH whose telephone number is (571)270-7096. The examiner can normally be reached M to F 8:30 AM-5:00 PM.
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/DAVID E SMITH/Examiner, Art Unit 2881
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