DETAILED ACTION
Claims 1-11 are pending before the Office for review.
In the response field February 27, 2026:
Claims 1-9 were amended.
Claim 12 was canceled.
No new matter is present.
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 .
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Claim Rejections - 35 USC § 102
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1 and 10-11 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by KARLIN et al (U.S. Patent Application Publication 2012/0107993).
With regards to claim 1, Karlin discloses a method of producing a microstructure that comprises silicon nitride (Si3N4) (44), the method comprising: -employing a hydrogen fluoride (HF) vapour to etch a sacrificial layer of silicon dioxide (SiO2) wherein the HF vapour also etches the silicon rich silicon nitride (Si2N4); and -once the HF vapour etch is complete, subsequently removing a solid silicon residue (56) formed by the HF vapour etching the silicon nitride (Si3N4) (44) (Figures 5-8 Paragraphs [0020]-[0028] discloses etching the silicon oxide layer with an HF vapour to form the residue 56 which is removed and further silicon nitride layer is removed). While Karlin does not explicitly disclose the residue is a solid silicon residue, Karlin’s residue would inherently comprise a solid silicon residue as Karlin’s process etches the same material, with the same processing vapour, at the same processing conditions (temperature and pressure) and would form residue of the same composition. Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). MPEP 2112.01
With regards to claim 10, Karlin discloses wherein the microstructure comprises a micro electromechanical systems (MEMS). (Paragraphs [0002], [0004]).
With regards to claim 11, Karlin discloses wherein the microstructure comprises a semiconductor device. (Paragraphs [0002]-[0005], [0018]-[0019]).
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 2 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over KARLIN et al (U.S. Patent Application Publication 2012/0107993) in view of O’HARA (U.S. Patent Application Publication 2009/0308843).
With regards to claims 2 and 9, Karlin discloses the limitations of claim 1 as previously discussed.
However Karlin is silent as to wherein the vapour etching of the sacrificial layer of silicon dioxide (SiO2) and the removal of the solid silicon residue are performed sequentially within separate processing chambers and employing a vacuum pumping system to remove by products formed when removing the solid silicon residue.
O’Hara discloses a method of etching a sacrificial oxide layer comprising performing the etching and residue removal step in the same or separate dedicated processing chambers (Paragraphs [0067]-[0068]) wherein volatile gases produced may be pumped away by a vacuum system (Paragraph [0067], [0075]) which renders obvious wherein the vapour etching of the sacrificial layer of silicon dioxide (SiO2) and the removal of the solid silicon residue are performed sequentially within separate processing chambers and employing a vacuum pumping system to remove by products formed when removing the solid silicon residue.
It would have been prima facie obvious to one of ordinary skill in the art prior to the effective filing date of the invention to modify the method of Karlin to include the separate chambers and pumping away as rendered obvious by O’Hara because the reference of O’Hara teaches that such pumping removes unwanted residues without rendering the MEMS structure susceptible to stiction (Paragraph [0068]) and one of ordinary skill in the art prior to the effective filing date of the invention would have had a reasonable expectation of predictably achieving the desired microstructure using the separate chamber and pumping as rendered obvious by O’Hara. MPEP 2143D
Claims 3-6 are rejected under 35 U.S.C. 103 as being unpatentable over KARLIN et al (U.S. Patent Application Publication 2012/0107993) in view of PARTRIDE et al (U.S. Patent Application Publication 2005/0106318).
With regards to claim 3, Karlin discloses the limitations of claim 1 as previously discussed.
However Karlin is silent as to wherein removing the solid silicon residue comprises reacting the solid silicon residue with a first additional gas.
Partridge discloses a method for etching a surficial silicon oxide layer comprising etching the silicon oxide layer with a HF vapour etching wherein subsequently the residue is treated in an ambient oxygen environment (Paragraphs [0073]-[0075]) which renders obvious wherein removing the solid silicon residue comprises reacting the solid silicon residue with a first additional gas
It would have been prima facie obvious to one of ordinary skill in the art prior to the effective filing date of the invention to modify the method of Karlin to include the reacting the solid silicon residue with a first additional gas (oxygen) as rendered obvious by Partridge because the reference of Partridge teaches that such oxidizing allows for the removal of the residue in a less time consuming manner (Paragraph [0074]) and one of ordinary skill in the art prior to the effective filing date of the invention would have had a reasonable expectation of predictably achieving the desired microstructure using the reaction with an additional gas as rendered obvious by Partridge. MPEP 2143D
With regards to claims 4-6, Karlin discloses the limitations of claim 1 as previously discussed.
However Karlin is silent as to wherein removing the solid silicon residue comprises reacting the solid silicon with a hydrogen or hydrogen compound gas to produce silane (SiH4), wherein removing the solid silicon residue comprises reacting the solid silicon with an oxygen or oxygen compound gas to produce a silicon dioxide (SiO2) and wherein removing the solid silicon residue further comprise employing a hydrogen fluoride (HF) vapour to etch the silicon dioxide (SiO2).
Partridge discloses a method for etching a surficial silicon oxide layer comprising etching the silicon oxide layer with a HF vapour etching wherein subsequently the residue is treated in an ambient oxygen environment to from an oxide layer and following oxidation is removed with an HF vapor etching (Paragraphs [0073]-[0075]) which renders obvious wherein removing the solid silicon residue comprises reacting the solid silicon with an oxygen or oxygen compound gas to produce a silicon dioxide (SiO2) and wherein removing the solid silicon residue further comprise employing a hydrogen fluoride (HF) vapour to etch the silicon dioxide (SiO2). While Partridge does not explicitly disclose the formation of silane (SiH4), the prior art render obvious removing the silicon residual by reaction a hydrogen compound gas of HF vapour which would produce silane. Where applicant claims a composition in terms of a function, property or characteristic and the composition of the prior art is the same as that of the claim but the function is not explicitly disclosed by the reference, the examiner may make a rejection under both 35 U.S.C. 102 and 103. "There is nothing inconsistent in concurrent rejections for obviousness under 35 U.S.C. 103 and for anticipation under 35 U.S.C. 102." In re Best, 562 F.2d 1252, 1255 n.4, 195 USPQ 430, 433 n.4 (CCPA 1977). This same rationale should also apply to product, apparatus, and process claims claimed in terms of function, property or characteristic. MPEP 2112(III)
It would have been prima facie obvious to one of ordinary skill in the art prior to the effective filing date of the invention to modify the method of Karlin to include the reacting the solid silicon residue with an oxygen compound and etchings with an HF vapour as rendered obvious by Partridge because the reference of Partridge teaches that such oxidizing allows for the removal of the residue in a less time consuming manner (Paragraph [0074]) and one of ordinary skill in the art prior to the effective filing date of the invention would have had a reasonable expectation of predictably achieving the desired microstructure using the oxygen gas and HF vapour etching as rendered obvious by Partridge. MPEP 2143D
Claims 7 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over KARLIN et al (U.S. Patent Application Publication 2012/0107993) in view of KORZENSKI et al (U.S. Patent Application Publication 2005/0118832).
With regards to claims 7 and 8, Karlin discloses the limitations of claim 1 as previously discussed.
However Karlin is silent as to wherein removing the solid silicon residue comprises reacting the solid silicon with a fluorine or fluorine compound gas to produce silicon tetrafluoride (SiF4) and wherein removing the solid silicon residue comprises etching the solid silicon with a Xenon Difluoride (XeF2) vapour.
Korzenski discloses a method of producing a microstructure wherein a sacrificial oxide layer may be etching using an HF vapour to produce a residue wherein the residue may be removed xenon difluoride vapour wherein the reacting forms volatile silicon tetrafluoride SiF4 (Paragraphs [0027]-[0032]) which renders obvious wherein removing the solid silicon residue comprises reacting the solid silicon with a fluorine or fluorine compound gas to produce silicon tetrafluoride (SiF4) and wherein removing the solid silicon residue comprises etching the solid silicon with a Xenon Difluoride (XeF2) vapour.
It would have been prima facie obvious to one of ordinary skill in the art prior to the effective filing date of the invention to modify the method of Karlin to include the fluorine compound gas and xenon difluoride vapour as rendered obvious by Korzenski because one of ordinary skill in the art prior to the effective filing date of the invention would have had a reasonable expectation of predictably achieving the desired microstructure using the fluorine compound gas and xenon difluoride vapour as rendered obvious by Korzenski. MPEP 2143D
Response to Arguments
Applicant's arguments filed February 27, 2026 have been fully considered but they are not persuasive.
In particular Applicant argues on pages 9-15 of Applicant’s response filed February 27, 2026 that the cited prior art fails to teach or render obvious Applicant’ claimed invention. Applicant argues that the cited prior art fails to teach or render obvious “… employing a hydrogen fluoride (HF) vapour to etch a sacrificial layer of silicon dioxide (SiO2) wherein the HF vapour also etches the silicon rich silicon nitride (Si3N4); and -once the HF vapour etch is complete, subsequently removing a solid silicon residue formed by the HF vapour etch.” Applicant argues that while Karlin discloses a method of manufacturing a MEMS device wherein an HF vapour etch of various oxide portions and layers is performed and wherein the silicon rich silicon nitride layer acts as an etch stop. In addition, Applicant argues that Karlin does not explicitly disclose that the residue 56 comprises solid silicon. In addition, Karlin does not disclose any method of removing a solid silicon residue. Applicant notes that while a residue is formed the methods recognized are not useful for removing a solid silicon. As such claim 1 must be considered as exhibiting the require novelty over the prior art. Claims 2-11 are allowable based on their dependency. This is found unpersuasive.
It is the Examiner’s position that the cited prior art teaches and renders obvious Applicant’s claimed invention including “… subsequently removing a solid silicon residue formed by the HF vapour etch.” There is no requirement that a person of ordinary skill in the art would have recognized the inherent disclosure at the relevant time, but only that the subject matter is in fact inherent in the prior art reference. Schering Corp. v. Geneva Pharm. Inc., 339 F.3d 1373, 1377, 67 USPQ2d 1664, 1668 (Fed. Cir. 2003) (MPEP 2112 (II)). "In relying upon the theory of inherency, the examiner must provide a basis in fact and/or technical reasoning to reasonably support the determination that the allegedly inherent characteristic necessarily flows from the teachings of the applied prior art." Ex parte Levy, 17 USPQ2d 1461, 1464 (Bd. Pat. App. & Inter. 1990) (emphasis in original). MPEP 2112(IV)
Karlin Paragraph [0025]
[0025] Shown in FIG. 6 is MEMS device after an oxide etch using vapor phase HF which removes oxide portions 30, 32, and 34 as well as oxide layers 46 and 40. Oxide portions 30, 32, and 34 may be considered sacrificial. SiRN layer 44 functions as an etch stop so that metal layer 42 does not receive the HF etch and is thus a protection layer as it protects metal layer 42. SiRN layer 44 is also etched but the vapor phase HF etch is tuned so that the oxide is etched much faster than SiRN. A consequence of this etch is residue 58 on nitride portions 24, 26, and 28 and a residue 56 on SiRN layer 44. The removal of oxide portions 32 and 34 has the effect of releasing the movable member portion of polysilicon layer 36 to be movable. Thus, the etch of oxide that has this effect in a MEMS device is sometimes called a release etch. Region 33 functions as a base for the movable member portion of polysilicon layer 36. At region 31 the portion of polysilicon layer 36 that is part of contact stack 54 makes contact to polysilicon portion 18 which in turn contacts the movable member at region 33. The HF etch, if it contacts metal layer 42, has been found to form a layer that is a compound comprising oxygen, aluminum, and fluorine. This compound makes it difficult to form a good electrical contact to metal layer 42. For example, gold does not adhere well to this compound. Further this compound is not easily removed. Residue 56 is also not good for forming electrical contact but residue is easily removed using techniques commonly used for cleaning after performing an etch. For example a rinse in hydrogen peroxide followed by a 350 degree Celsius bake is effective and which also is effective in removing residue 58. Vapor phase HF processes may include tools wherein either an anhydrous HF liquid mixture is evaporated to form HF vapor or gaseous nitrogen is bubbled through a highly concentrated solution of HF and water. An effective process diluent is nitrogen gas. Gaseous isopropyl alcohol or similar hydrophobic compounds may be also added to the process in order to promote effective drying of the MEMS device. Processing chambers may operate at atmospheric pressure or at sub-atmospheric pressures. The temperature of the reaction may be held at room temperature or be performed at elevated temperatures (25-50 deg C.). Further the process parameters are adjustable to achieve different rates for SiRN compared to deposited oxide. For example, the rate of oxide etching can be more than four times that of SiRN. This allows for flexibility in selecting the thickness of the SiRN layer.
It is the Examiner’s position that Karlin is etching Applicant’s claimed material, using Applicant’s claimed HF vapor under processing conditions that fall within Applicant’s processing conditions (see Paragraphs [0030]-[0031] of Applicant’s published specification. As such it is the Examiner’s position that Karlin would inherently form Applicant’s claimed solid silicon residue as Karlin anticipates Applicant’s claimed method. Applicant has not provided evidence that discredits the Examiner’s assertion that Karlin would inherently form Applicant’s claimed solid silicon residue. "[T]he PTO can require an applicant to prove that the prior art products do not necessarily or inherently possess the characteristics of his [or her] claimed product. Whether the rejection is based on ‘inherency’ under 35 U.S.C. 102, on ‘prima facie obviousness’ under 35 U.S.C. 103, jointly or alternatively, the burden of proof is the same." In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433-34 (CCPA 1977) (footnote and citation omitted). The burden of proof is similar to that required with respect to product-by-process claims. In re Fitzgerald, 619 F.2d 67, 70, 205 USPQ 594, 596 (CCPA 1980) (citing Best, 562 F.2d at 1255). MPEP 2112(V) Applicant argues that a hydrogen peroxide rinse would not be capable of removing a solid silicon residue however Applicant has not provided evidence to support this assertion. "[T]he PTO can require an applicant to prove that the prior art products do not necessarily or inherently possess the characteristics of his [or her] claimed product. Whether the rejection is based on ‘inherency’ under 35 U.S.C. 102, on ‘prima facie obviousness’ under 35 U.S.C. 103, jointly or alternatively, the burden of proof is the same." In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433-34 (CCPA 1977) (footnote and citation omitted). The burden of proof is similar to that required with respect to product-by-process claims. In re Fitzgerald, 619 F.2d 67, 70, 205 USPQ 594, 596 (CCPA 1980) (citing Best, 562 F.2d at 1255). MPEP 215 (I) Therefore it is the Examiner’s position that Karlin anticipates Applicant’s currently presented claim 1. As to the dependent claims they remain rejected based on their dependency as no separate arguments have been provided.
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 STEPHANIE P. DUCLAIR whose telephone number is (571)270-5502. The examiner can normally be reached 9-6:30 M-F.
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/STEPHANIE P DUCLAIR/Primary Examiner, Art Unit 1713
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