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
Claims 3, 7, 11-12 and 15 are objected to because of the following informalities:
Claim 3 recites “remove residues potentially present after step d on the one or more scanning probe microscopy tip,” should be “one or more …tips”.
Claim 7 recites “The method according to claim 1, comprising on its surface,” should be “The method according to claim 1, wherein the substrate comprises on its surface…”
Claim 11 recites “…wherein either the top surface of the substrate is made of … each step alternating etching with SF6, CF4, or a mixture thereof with etching with C4F8,” which is grammatically confusing, the claimed element should be read as “wherein 6, CF4, or a mixture thereof, with etching with C4F8.”
Claim 12 recites “wherein in steps a and d the flow rate used for SF6, CF4, or the mixture thereof is larger than the flow rate used for C4F8 while in step b, the flow rate used for SF6, CF4, or the mixture thereof is lower than the flow rate used for C4F8,” which is grammatically confusing, the claimed element should be read as “wherein in steps a and d the flow rate used for SF6, CF4, or the mixture thereof is larger than the flow rate used for C4F8 ; while in step b, the flow rate used for SF6, CF4, or the mixture thereof is lower than the flow rate used for C4F8.”
Claim 15 recites “performing said scanning probe microscopy measure,” should be “performing…. measurement.”
Appropriate correction is required.
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.
Claims 6 and 8-10 are 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 6 recites “The method according to claim 1, further comprising, after the last of steps d, and the one or more sharpening and/or cleaning steps…,” There is insufficient antecedent basis for this limitation in the claim since claim 1 does not require sharpening/cleaning steps.
Claim 8 recites “The method according to claim 1, …as well as the one or more sharpening and/or cleaning steps if performed…” There is insufficient antecedent basis for this limitation in the claim since claim 1 does not require sharpening/cleaning steps. Also, the phrase “if performed” makes the claim unclear whether the sharpening/cleaning steps are required by the claim.
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 1-2, 4-6, 8-10, and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Shin, Y., et al., (2018). Single‐mask fabrication of micro‐probe electrode array with various tip heights and sharpness using isotropic and anisotropic etching. Micro & Nano Letters, 13(9), 1245–1247. [hereinafter Shin].
Regarding Claim 1:
Shin teaches a method of fabricating a substrate comprising on its surface one or more scanning probe microscopy tips (Abstract: a silicon-based micro-probe array was fabricated using multi-step deep reactive ion etching (DRIE) and reactive ion etching (RIE) processes), the method comprising:
a) underetching beneath one or more hardmasks, present on a substrate, thereby forming a corresponding number of pre-tip structures having an upper part, a lower part, and a neck region linking the upper part to the lower part (annotated Fig. 1 (a)-(b) and Page 1: “A silicon wafer with the thickness of 525 µm and the diameter of 4 in. was used as the substrate for the micro-probe array… This SiO2 film is used as a hard mask in all the dry etching steps to form the micro probe structure… the vertical silicon pillar is formed using standard anisotropic DRIE…The vertical silicon pillar is then etched isotropically using the RIE process to form the cone-shaped tip part,” including an upper part, a neck, and a lower part, as shown in annotated Fig. 1 (b) below);
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b) then, etching the substrate underneath each pre-tip structure in a vertical manner using the respective hardmask as an etching mask, thereby forming a pedestal beneath the lower part of each pre-tip structure (annotated Fig. 1(c) and Page 1: “Next, the silicon was anisotropically etched using the second DRIE process with oxide mask on top of the pillar,” forming a pedestal/base beneath the pre-tip as shown in annotated Fig. 1(c) above);
c) then, selectively removing the hardmask from each pre-tip structure (Fig. 1(d) and Page 2: “The micro probe structure was completed through the second RIE process (Fig. 1d).” As shown in Fig. 1(d), the oxide mask/top cap on each pre-tip structure is removed at/after this step); and
d) then, thinning down the neck region until the upper part is physically detached from the lower part, thereby forming the substrate comprising on its surface the one or more scanning probe microscopy tips (Fig. 1(d) and Pages 1-2: “The conical tip height and sharpness were
primarily controlled using the first DRIE and RIE processes… [until] the top part on the conical silicon tip was detached from the micro-probe’s body and the sharp tip end was formed after the second RIE process”).
Although Shin does not expressly state their hardmask as “rotationally symmetric,” Shin describes the vertical silicon pillar formed underneath the hardmask as having a “diameter” of 80µm and shows cylindrical micro-probes, which suggests a circular mask. Therefore, it would have been obvious for an ordinary skilled person in the art, before the effective time of filing, to uses a circular/ rotationally symmetric mask in light of Shin’s teaching, since Shin seeks to form a conical sharp tip, and a circular mask would predictably produce a centered conical tip during isotropic etching.
Regarding Claim 2:
Shin teaches the method of Claim 1. Shin further teaches the method comprising one or more sharpening and/or cleaning steps after step d, thereby forming the substrate comprising on its surface the one or more scanning probe microscopy tips (Page 2: after the top part of the tip is detached, perform “the RIE process to remove the Parylene-C at the tip-end,” i.e., a cleaning step).
Regarding Claim 4:
Shin teaches the method of Claim 1. Shin further teaches wherein the method is executed in the same etch tool (Shin uses a single fabrication flow with first DRIE, first RIE, second DRIE, and second RIE, the expressly states the isotropic RIE was conducted under silicon etching conditions in the standard DRIE process without polymer deposition/removing steps, indicating the RIE/DRIE steps can be implemented in the same DRIE/ICP tool by changing recipes).
Regarding Claim 5:
Shin teaches the method of Claim 1. Shin further teaches wherein the top surface of the substrate comprises one or more layers selected from layers made of silicon, silicon-germanium, germanium, silicon carbide, diamond, quartz and glass (Shin uses a silicon wafer).
Regarding Claim 6:
Shin teaches the method of Claim 1. Shin further teaches after the last of steps d, and the one or more sharpening and/or cleaning steps, applying a coating to the fabricated scanning probe microscopy tips, wherein said coating is one of diamond, doped diamond, a metal, a metal alloy, an oxide, or a nitride (after the tip is formed (step d), “Cr/Au (100/1000 Å) was deposited as a conductive layer on the micro-probe,” where Cr/Au is a metal/metal alloy coating).
Regarding Claim 8:
Shin teaches the method of Claim 1. Shin further teaches wherein steps a, b, c, and d, as well as the one or more sharpening and/or cleaning steps if performed, are dry etching steps (Shin’s main shaping steps are DRIR and RIE, both are dry etching processes).
Regarding Claim 9:
Shin teaches the method of Claim 8. Shin further teaches wherein the dry etching steps are inductively coupled plasma etching steps (Page 1: “the vertical silicon pillar is formed using standard anisotropic DRIE in an inductively coupled plasma etcher”).
Regarding Claim 10:
Shin teaches the method of Claim 9. Shin further teaches wherein either the top surface of the substrate is made of silicon, silicon-germanium, germanium, silicon carbide, or glass and steps a, b, and d are inductively coupled plasma etching steps making use of halogen-containing etching gases (Page 12: In Shin, “the vertical silicon pillar is formed using standard anisotropic DRIE in an inductively coupled plasma etcher ” with SF6 and C4F8 gas flow, both are halogen-containing gases), or the top surface of the substrate is made of diamond and steps a, b, and d are inductively coupled plasma etching steps making use of oxygen-containing gases.
Regarding Claim 14:
Shin teaches the method of Claim 2.
Shin further teaches wherein the one or more sharpening steps are inductively coupled plasma etching steps making use of halogen-containing etching gases (Page 1: “The gas flow rate of SF6, C4F8 and Ar is 100, 0.5…The silicon pillars were sharpened in this process due to the etch rate variation at the sidewall of the pillar”).
Although Shin’s sharpening is performed before the final detachment step, it would be obvious to perform the same sharpening process again after the top-part detachment if the formed tip apex required further sharpening.
Claims 7, 11-13 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Shin in view of SCAMPORRINO, G., "Design, fabrication and evaluation of silicon tip chips for reverse tip sample scanning probe microscopy.," Master's Thesis, Nanotechnologies for ICTs, pp. 1-89 (2021) [hereinafter Scamporrino].
Regarding Claim 7:
Shin teaches the method of claim 1. Shin expressly discloses fabricating a “a silicon-based micro-probe array.” However, Shin does not specially note that wherein the substrate comprises on its surface on array of at least 100, at least 1,000, at least 10,000, or at least 500,000 scanning probe microscopy tips, wherein the one or more hardmasks are an array of at least 100, at least 1,000, at least 10,000, or at least 500,000 hardmasks.
Scamporrino teaches an array of at least 500,000 scanning probe microscopy tips, wherein the one or more hardmasks are an array of at least 500,000 hardmasks (Page 36: Fig. 3.4 shows a 5mm * 5mm tip chip with tips arranged 10 rows and 3 columns matrices, for a total of 5400 tips. Scamporrino also explains that “lithographic mask will then be used … to transfer its geometry into the resist…[then] transferred to the substrate.” Since the disclosed chip has 5400 tips, it necessarily requires to use a corresponding array of mask/resist features for those tips).
Therefore, it would have been obvious for an ordinary skilled person in the art, before the effective time of filing, to fabricate Shin’s silicon micro-probe array with at least 100 or 1,000 probes/tips, as taught by Scamporrino, because both references use silicon lithography/dry-etch process to form sharp probe-tip arrays, and Scamporrino demonstrates that the same type of process is suitable for mass-producing thousands of tips on a single tip chip.
Regarding Claim 11:
Shin teaches the method of claim 1. Shin teaches its top surface of the substrate is made of silicon, and steps a, b, and d are inductively coupled plasma etching steps, as discussed in claim 10. Shin also states both SF6 and C4F8 are used in their etching steps. However, Shin does not specially note their etching steps comprising alternating between an etching sub-step using SF6, CF4, or a mixture thereof, and C4F8.
Scamporrino teaches that, for silicon dry etching, fluorine gases such as SF6/CF4 etch silicon, while C4F8 is used as a passivating gas to deposit polymer protecting the sidewalls, Scamporrino also explains that SP6 alone gives almost isotropic etching, so C4F8 is needed for high aspect ratio structures (Pages 41-42: “Fluorine-based gases, such as SF6 have a high etching rate on silicon since fluorine reacts more effectively with silicon producing SiF4, … To obtain high-aspect-ratio structures, SF6 cannot be used alone as it performs an almost isotropic etching… For this reason it is also necessary to use a passivating gas that protects the sidewalls making the etching more anisotropic. The passivation gas used is C4F8 and the process in which it is used is called Pseudo Bosch process”).
Therefore, it would have been obvious for an ordinary skilled person in the art, before the effective time of filing, to implement Shin’s DRIE/RIE silicon-tip etches as alternating SF6/C4F8 ICP etching steps so that during the fabrication, the SF6 provides silicon etching while C4F8 provides sidewall passivation, and that adjusting the SF6/C4F8 balance controls anisotropy, tapering, and underetching in silicon tip fabrication.
Regarding Claim 12:
Shin in view of Scamporrino teach the method of claim 11. The combined references further teach wherein in steps a and d the flow rate used for SF6, CF4, or the mixture thereof is larger than the flow rate used for C4F8 while in step b, the flow rate used for SF6, CF4, or the mixture thereof is lower than the flow rate used for C4F8 (Since Scamporrino teaches that SF6 promotes silicon etching while C4F8 deposits passivating polymer on the sidewall and increase etch anisotropy, it would be obvious to use a higher SF6 flow than C4F8 in Shin’s underetching/sharpening steps a and d, and a higher C4F8 flow than SF6 in the vertical pedestal-forming step b).
Regarding Claim 13:
Shin teaches the method of claim 2. However, Shin does not specially note that wherein the one or more cleaning steps are inductively coupled plasma etching steps making use of oxygen-containing gases. Scamorrino teaches wherein the one or more cleaning steps are inductively coupled plasma etching steps making use of oxygen-containing gases (Pages 51-52 and 40: “The resist mask…can be easily reduced in size through an oxygen plasma etching… The size reduction of the resist mask and the final resist removal were carried out by means of oxygen stripping tool,” and identifies the tool sued for the dry etching work as an Oxford Plasmalab 100 inductively coupled plasma (ICP) reactive ion etcher (RIE)”).
Regarding Claim 15:
Scamorrino teaches a method for performing a scanning probe microscopy measurement of a sample (Page 27: “RTS SPM working principle”), the method comprising:
providing a substrate comprising on its surface a plurality of scanning probe microscopy tips (Page 27: “the tip is located on the stage,” Fig. 2.12 shows a sample surface having “thousands of tips available during the measurement”);
attaching a sample to the end of a cantilever (Page 27: “The sample is…placed at the end of the cantilever”); and
moving said sample relative to one or more of said scanning probe microscopy tips (Pages 27: “In this way the tip will remain fixed while the sample will be scanned, moving the cantilever, on it”); and
performing said scanning probe microscopy measure on said sample (performing the RTS-SPM measurement).
However, Scamporrino does not specially not the tip is produced by the method of claim 1. Shin teaches fabricating a silicon micro-probe array using the method of claim 1, as discussed.
Therefore, it would have been obvious for an ordinary skilled person in the art, before the effective time of filing, to use the plurality of sharp silicon tips produced by Shin in the RTS SPM measurement configuration taught by Scamporrino, because both references concern silicon/probe-tip array fabricated using semiconductor microfabrication technique, and use Shin’s sharp silicon tip array as the tip substrate in Scamporrino’s RTS-SPM method would obtain the predictable benefits of rapid tip switching, reduced manual probe replacement, and improved SPM measurement throughput.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Shin in view of US20140134336A1 [hereinafter Ha].
Regarding Claim 3:
Shin teaches the method of 2. Shin further teaches a sharpening process during its tip fabrication (page 1: “The silicon pillars were sharpened in this process due to the etch rate variation at the sidewall of the pillar,” using SF6 and C4F8 gas flow, forming the cone-shaped tip part as shown in Fig. 1(b))). Although Shin’s sharpening is performed before the final detachment step, it would be obvious to perform the same sharpening process again after the top-part detachment if the formed tip apex required further sharpening.
However, Shin does not teach a repeated cleaning process. Ha teaches a repeated tip-cleaning process (para. [0040]: “The AFM tip cleaning may include repeatedly cleaning the AFM tip with the first and second cleaning portions which comprise two or more cleaning portions”).
Therefore, it would have been obvious for an ordinary skilled person in the art, before the effective time of filing, to modify the fabrication process of Shin with the repeated cleaning steps as taught by Ha, to clean the formed tip before additional sharpening to remove fabrication residuals, then perform the sharpening if additional tip sharpness is desired, and clean the tip again to remove any residuals from fabrication and the additional sharpening process, thus the sharpening acts uniformly on the tip after the pre-sharpen cleaning, and the final tipis both sharper and cleaner for reliable SPM measurement.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JING WANG whose telephone number is (571)272-2504. The examiner can normally be reached M-F 7:30-17:00.
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/JING WANG/Examiner, Art Unit 2881
/DAVID E SMITH/Examiner, Art Unit 2881
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