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 Objections
Claim 17 is objected to because of the following informalities: “XF2” should recite - - XeF2 - - in order to refer to the chemical symbol for xenon. Appropriate correction is required.
Claim Rejections - 35 USC § 102
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 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.
Claims 1-8 and 10-16 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Gutierrez (“Multiplexing of electrospray sources for space propulsion and physical sputtering” 2015).
Gutierrez discloses a fabrication method for an emitter electrode of an electrospray thruster (page 24, Fig. 10) configured to provide electrostatic acceleration of charged droplets and ions produced by electrospraying a liquid propellant (page 29, Fig. 15, “integrated electrospray head”), the method comprising:
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Gutierrez, Fig. 10
etching at least one microfluidic channel on a backside of a wafer (Fig. 10, step (3)), wherein the at least one microfluidic channel provides hydraulic impedance to the flow of the liquid propellant (page 23, last paragraph “channels responsible for the hydraulic impedance”; the same structure is constructed as in the instant invention, and therefore the same results are expected, inherently);
etching an emitter array on a front side of the wafer (see page 23, section titled “Emitter array fabrication” and Fig. 10, step (6)), wherein the emitter array comprises at least one emitter:
wherein the liquid propellant reaches a tip of the at least one emitter through an inner channel etched through the at least one emitter (“central hole is pre-etched” and “then carved for 300 μm” Fig. 10, step 10); and
wherein each channel of the at least one microfluidic channel feeds liquid propellant to the at least one emitter of the emitter array via a hole communicating the at least one microfluidic channel with the inner channel of the at least one emitter (as depicted and described in Fig. 15, page 29, in the integrated electrospray source head, a capillary is for feeding the liquid propellant).
As to claim 2, Gutierrez discloses that the wafer is a double-polished silicon wafer (page 23, last paragraph).
As to claim 3, Gutierrez discloses patterning on the backside using photoresist as cited (page 23, “Shipley 1827 photoresist” step (2)).
As to claim 4, Gutierrez discloses etching with DRIE for 20 μm and stripping the photoresist (page 23, description of step (3)). Gutierrez fails to explicitly disclose that the “20 μm” DRIE is a “timed DRIE” as cited in claim 4. However, one with ordinary skill in the art would immediately envisage that a timed etch is meant by the description of 20 μm etch, and thus this description anticipates the claimed invention.
As to claims 5 and 7, Gutierrez discloses providing SiO2 by PECVD on the backside of the wafer (Fig. 10, step (5) with the wafer flipped; page 24, line 1; the wafer is “flipped” and the new topside is the original backside).
As to claim 6, Gutierrez discloses “steamed oxidized at 1100 °C for 2 hours growing a layer of 1 μm Silicon Dioxide” at step 4 (page 23, last two lines). This would inherently also grow SiO2 by thermal oxidation as cited because an extra masking is not provided to protect the backside from thermal oxidation.
As to claim 8, the thermal oxidation as described with respect to claim 6 also inherently provides thermal oxide on the front side of the wafer as cited because an extra masking is not provided to protect the front side from thermal oxidation.
As to claim 10, Gutierrez discloses an “AZ4620 layer” which is a lithography mask that is used to etch the SiO2 on the front side of the wafer (page 24, step (6)). As depicted in Fig. 10, step (9), the SiO2 mask is for pattering the well and emitter geometry on the front side of the wafer.
As to claim 11, as depicted in Fig. 10, steps (10) and (11), the well and emitter geometry on the front side and microfluidic channel on the back side are aligned.
As to claim 12, Gutierrez discloses DRIE as cited (page 24, Fig. 10, step (10)).
As to claim 13, Gutierrez discloses partially etching as cited (Fig. 10, step (9)).
As to claim 14, Gutierrez discloses that the well and inner channels are etched as cited (Fig. 10, step (9)).
As to claim 15, Gutierrez discloses connecting by DRIE as cited (“last DRIE etch” page 24, step (10)).
As to claim 16, as broadly interpreted, the DRIE also shapes the emitter tip.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Gutierrez (“Multiplexing of electrospray sources for space propulsion and physical sputtering” 2015), as applied to claim 8, and further in view of Sarrut et al (US 2010/0018864 A1).
As to claim 9, Gutierrez discloses to form SiO2 on the front side by thermal oxidation. Gutierrez fails to disclose depositing SiO2 by PECVD. Sarrut teaches that in methods of etching to form microstructures in silicon substrates, similar to Gutierrez, that a silicon plate 41 is coated with PECVD oxide to form an etch mask [0076]. It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to form the silicon dioxide in the method of Gutierrez by PECVD because Sarrut teaches that it is a known and useful technique for forming silicon oxide layers, and such is expected to give the predictable result of a mask layer useful for further etching of the silicon substrate.
Claims 17-18 are rejected under 35 U.S.C. 103 as being unpatentable over
Gutierrez (“Multiplexing of electrospray sources for space propulsion and physical sputtering” 2015), as applied to claim 16, and further in view of Perna et al (US 2020/00373141 A) and Espinosa et al (US 2007/0151989 A1).
As to claim 17, Gutierrez fails to disclose xenon difluoride etching. Perna teaches that in forming electrospray emitter tips (see abstract), that the edge of the shape can usefully be linear, curved, or of other shapes [0042]. However, Perna fails to disclose how form the different shapes.
Espinosa teaches that tips can be shaped by various etching techniques such as xenon difluoride etching [0042].
It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to form a shaped tip in the method of Gutierrez because Perna teaches that various tip geometries are useful for electrospray emitter tips and such are expected to give the predictable results of an electrospray emitter for the tip formed in the method of Gutierrez.
It would have been further obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to shape the tip by xenon difluoride etching in the modified method of Gutierrez because Espinosa teaches that it is a useful etchant for forming the tip shapes taught by Gutierrez as modified by Perna to be useful for electrospray emitter tips.
As to claim 18, Espinosa teaches that tips can be shaped by various etching techniques such as HNA etching (hydrofluoric acid, nitric acid, and acetic acid) [0042]. It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to shape the tip by wet etching with hydrofluoric acid, nitric acid, and acetic acid in the modified method of Gutierrez because Espinosa teaches that it is a useful etchant for forming the tip shapes taught by Gutierrez as modified by Perna to be useful for electrospray emitter tips.
Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over
Gutierrez (“Multiplexing of electrospray sources for space propulsion and physical sputtering” 2015) in view of Perna et al (US 2020/00373141 A) and Espinosa et al (US 2007/0151989 A1), as applied to claim 18, and further in view of Jung-Kubiak et al (US 10,384,810 B2).
As to claim 19, Gutierrez fails to disclose coating with a noble metal. Jung-Kubiak teaches that it is useful to coat electrospray emitter tips with gold, which is a noble metal, to encourage the flow of propellant along the emitters during operation (col.10, lines 24-27). Encouraging flow encompasses eliminating clogging because the same material is formed as in the instant invention, therefore the same results are expected.
It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to provide a noble metal such as gold as cited in the modified method of Gutierrez because Jung-Kubiak teaches that to do so is useful for encouraging flow of propellant along the emitters during operation.
Claim 20 is rejected under 35 U.S.C. 103 as being unpatentable over Gutierrez (“Multiplexing of electrospray sources for space propulsion and physical sputtering” 2015), as applied to claim 20, and further in view of Perna et al (US 2020/00373141 A).
As to claim 20, Gutierrez discloses to remove the silicon oxide with hydrofluoric acid (page 24, step (11)), but fails to explicitly disclose a buffered oxide etch (BOE). Perna teaches that a BOE is useful for removing silicon oxide [0062]. It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to remove with BOE in the method of Gutierrez because Perna teaches that it is a useful technique for removing silicon oxide layer and such is expected to give the predictable result of a removed layer.
Claim 21 is rejected under 35 U.S.C. 103 as being unpatentable over
Gutierrez (“Multiplexing of electrospray sources for space propulsion and physical sputtering” 2015), as applied to claim 1, and further in view of Jung-Kubiak et al (US 10,384,810 B2).
As to claim 21, Gutierrez fails to disclose coating with a noble metal. Jung-Kubiak teaches that it is useful to coat electrospray emitter tips with gold to encourage the flow of propellant along the emitters during operation (col.10, lines 24-27). Encouraging flow encompasses eliminating clogging because the same material is formed as in the instant invention, therefore the same results are expected.
It would have been obvious to one with ordinary skill in the art before the effective filing date of the claimed invention to provide a noble metal such as gold as cited in the modified method of Gutierrez because Jung-Kubiak teaches that to do so is useful for encouraging flow of propellant along the emitters during operation.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Smith et al (US 2022/0068623 A1) is cited to show a method of forming electrospray devices, including also various deposition techniques [0054] and BOE [0062].
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/ANITA K ALANKO/Patent Examiner, Art Unit 1713