DETAILED ACTION
Claims 1-2 and 4-11 are pending before the Office for review.
In the response filed August 28, 2026:
Claim 1 was amended.
Claim 3 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.
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on August 28, 2026 has been entered.
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 1, 4-6 and 10-11 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 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
However, Karlin does not explicitly disclose wherein removing the solid silicon residue comprises reacting the solid silicon residue with an additional gas.
Partridge discloses a method for etching a sacrificial 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, the modified teachings of Karlin renders obvious 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 (Partridge 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 Karlin as modified by 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)
With regards to claim 10, the modified teachings of Karlin disclose wherein the microstructure comprises a micro electromechanical systems (MEMS). (Karlin Paragraphs [0002], [0004]).
With regards to claim 11, the modified teachings of Karlin discloses wherein the microstructure comprises a semiconductor device. (Karlin Paragraphs [0002]-[0005], [0018]-[0019]).
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 PARTRIDE et al (U.S. Patent Application Publication 2005/0106318), as applied to claims 1, 4-6 and 10-11, in further view of O’HARA (U.S. Patent Application Publication 2009/0308843).
With regards to claims 2 and 9, the modified teachings of Karlin renders obvious the limitations of claim 1 as previously discussed.
However, the modified teachings Karlin are 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 further modify the modified 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 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 PARTRIDE et al (U.S. Patent Application Publication 2005/0106318), as applied to claims 1, 4-6 and 10-11, in further view of KORZENSKI et al (U.S. Patent Application Publication 2005/0118832).
With regards to claims 7 and 8, the modified teachings of Karlin renders obvious the limitations of claim 1 as previously discussed.
However, the modified teachings of Karlin are 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 further modify the modified 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, see pages 5-6 of Applicant’s response, filed August 28, 2026, with respect to the rejection(s) of claim(s) 1 and 10-11 under 102 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of PARTRIDE et al (U.S. Patent Application Publication 2005/0106318).
Applicant's remaining arguments filed August 28, 2026 have been fully considered but they are not persuasive.
Applicant argues on pages 5-10 of Applicant’s response that the cited prior art fails to teach or render obvious Applicant’s claimed invention. In particular, Applicant argues that the cited prior art fails to teach or render obvious “…once the HF vapour etch is complete, subsequently removing a solid silicon residue formed by the HF vapour etch, wherein removing the solid silicon residue comprises reacting the solid silicon residue with an additional gas.” Applicant argues that Karlin does not disclose to remove the residue 56 by reacting with an additional gas. Applicant argues that during fabrication the effect of stiction is difficult to overcome. Applicant argues that the prior art does not recognize this disadvantage.
In addition, Applicant argues that prior art does not recognize that the residue formed by the HF vapour etch comprises solid silicon and rather attributes any presence of silicon to the underlying silicon substrate. Aa key inventive, non-obvious concept comprises performing a "dry" process of removing the residue to avoid the risk of stiction. Applicant maintains that Karlin fails to disclose or render obvious Applicant’s solid residue. In addition, Karlin silent with regard to such modifications and so clearly does not recognize the problem solved by the present invention. Applicant argues that any modification is based on impermissible hindsight reasoning.
It is Applicant’s position that based on the teachings of Karlin, the skilled person may have been motivated to perform a HF vapour etch followed by a hydrogen peroxide rinse. As such, Applicant maintains that the cited prior art fails to teach or render obvious Applicant’s claimed invention as presented in claim 1. As to the dependent claims they are allowable based on their dependencies. This is found unpersuasive.
It is the Examiner’s position that the cited prior art renders obvious Applicant’s claimed invention including “…once the HF vapour etch is complete, subsequently removing a solid silicon residue formed by the HF vapour etch, wherein removing the solid silicon residue comprises reacting the solid silicon residue with an additional gas.”
In response to applicant's argument that the examiner's conclusion of obviousness is based upon improper hindsight reasoning, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971).
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 discloses that it would not be beneficial to keep the residue and further that such residue can be removed by techniques commonly known for cleaning after performing and etch. While Karlin, in particular discloses rinsing with a hydrogen peroxide rinse, the prior art is not limited to this particular example. "The use of patents as references is not limited to what the patentees describe as their own inventions or to the problems with which they are concerned. They are part of the literature of the art, relevant for all they contain." In re Heck, 699 F.2d 1331, 1332-33, 216 USPQ 1038, 1039 (Fed. Cir. 1983) (quoting In re Lemelson, 397 F.2d 1006, 1009, 158 USPQ 275, 277 (CCPA 1968)). MPEP 2123(I) It is the Examiner’s position that Karlin discusses removing the residue and further one of ordinary skill in the art would look to Patridge because Partridge teaches that such oxidizing allows for the removal of the residue in a less time consuming manner (Paragraph [0074]). While the prior art does not recognize the issue of striction, Applicant’s reasoning for modification is not required but rather one of ordinary skill in the art would be motivated to perform the modification without the benefit of Applicant’s invention. It is the Examiner’s position that one of ordinary skill in the art would be motivated to modify Karline with the teachings of Partridge for the reasons provided.
In addition, the Examiner maintains that the prior art renders obvious the formation of a solid silicon residue. 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)
Finally Applicant’s representative discuss the effects of stiction but the Examiner has not found support for the attorney’s arguments. Arguments presented by applicant cannot take the place of evidence in the record. See In re De Blauwe, 736 F.2d 699, 705, 222 USPQ 191, 196 (Fed. Cir. 1984). MPEP 2145(I) Applicant’s speciation does not appear to discuss the effects of stiction nor has Applicant’s representative pointed to support for the attorney’s arguments.
As such the Examiner maintains the rejection on record. As to the dependent claims they remain rejected as no separate arguments have been provided.
Conclusion
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.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Joshua Allen can be reached at 571-270-3176. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/STEPHANIE P DUCLAIR/Primary Examiner, Art Unit 1713
Prosecution Insights