DETAILED ACTION
Information Disclosure Statement
The information disclosure statement (IDS) submitted 4/15/2026 is in compliance with the provisions of 37 CFR 1.97 and being considered by the examiner.
Response to Amendment
The amendment filed 4/2/2026 has been entered. Claims 1-20 remain pending in the application. Applicant’s amendment of claim 11 has overcome the rejections of claims 11-13 set forth in the Non-Final Office Action mailed 1/2/2026 (“FAOM”), which are hereby withdrawn.
Response to Argument
Applicant's arguments, see pages 7-12 of the Remarks filed 4/2/2026 (“Remarks”), with respect to the remaining rejections of record have been fully considered and found partially persuasive, as set forth below.
Regarding the rejection of claims 1 and 16 over Burak (PGPUB 2016/0087186), the applicant argues (Remarks at 7-8):
The "support frames""960" and "950" disclosed in Burak include "air-gaps" 961-964 and "air-gaps" 951-954 described in paragraphs 0080 and 0082. Applicant respectfully submits that nothing in Burak discloses that such support frames with air gaps could correspond to a temperature compensation layer (e.g., air gaps may disrupt coupling to the piezoelectric layer and would fail to provide opposing temperature dependent strain in the piezoelectric layer in such regions). Burak fails to disclose temperature compensation of frequency or that the support frames include characteristics of a temperature compensation layer.
The examiner respectfully disagrees. First, in response to the applicant's argument that Burak fails to show certain features of the invention, it is noted that the features upon which the applicant relies (i.e., temperature compensation layers without any gaps) are not recited in the rejected claims. Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). Even layers with air-gaps disclosed in Burak meet the claim limitations, as currently recited.
Second, it does not matter whether a layer is called a “dielectric layer” or a “temperature compensation layer” because its physical properties and temperature characteristics are determined by the disclosed materials and positions, regardless of labels used in prior art. As set forth in the FAOM (pp. 2-4) and below, Burak discloses a first layer (support frame 960 formed of SiC) and a second layer (support frame 950 formed of SiC) disposed on the first and second surfaces of the piezoelectric layer, respectively, as required by claims 1 and 16. Because the two SiC layers have a temperature coefficient of frequency different from that of the piezoelectric layer, the two SiC layers provide temperature compensation of frequency due to their material properties and positions. The rejected claims, as recited, require nothing else.
The applicant’s argument for claims 2-5 and 17-19, dependent on claims 1 and 16, respectively, was not found persuasive for the same reasons. Therefore, the rejections of claims 1-10 and 14-20 over Burak are maintained.
Regarding the rejection of claims 11-13 over Burak, the examiner agrees with the applicant's argument that the feature of "the cavity is between the first TCF compensation layer and the electrode structure in the third direction," in combination with the remaining limitations of the amended claim 11, is not disclosed in the prior art of record. See “Allowable Subject Matter” section below.
Regarding the rejection of claims 1 and 16 over Jachowski (PGPUB 2023/0283256) in view of McHugh (PGPUB 2022/0231658) the applicant argues (Remarks at 9-11):
Applicant respectfully submits that it would not have been obvious to modify the "shear wave XBAR" of Jachowski with a "decoupling dielectric layer" because a significant feature of the "shear wave XBAR" appears to be the coupling strength but adding the "decoupling dielectric layer" of McHugh would reduce that coupling strength. Accordingly, the suggested combination would render the "shear wave XBAR resonator" of Jachowski unsatisfactory for its intended purpose. Under MPEP 2143.01 (V), "If a proposed modification would render the prior art invention being modified unsatisfactory for its intended purpose, there may be no suggestion or motivation to make the proposed modification." For at least this reason, Applicant respectfully submits that it would not have been obvious to modify Jachowski based on McHugh, as suggested. Accordingly, the features of claim 1 would not have been obvious based on Jachowski in view of McHugh.
The examiner respectfully disagrees. The applicant does not provide any evidence that Jachowski could not be modified as taught by McHugh (FAOM at 6-7). Even assuming the applicant is correct that the proposed modification “would reduce that coupling strength” of the XBAR disclosed in Jachowski, there is no evidence that the modification would render it inoperable (MPEP 2143.01.V) or would change its principle of operation (MPEP 2143.01. VI). In fact, McHugh’s decoupling dielectric layer is used in an XBAR disclosed therein, which remains satisfactory for its intended purpose. McHugh explicitly teaches that “the decoupling dielectric layer 450 provides an important secondary benefit of lowering the temperature coefficient of frequency (TCF) of the XBAR 400 as compared to XBAR 100.” (¶¶41-42). For the foregoing reasons, the applicant has failed to rebut the prima facie case of obviousness and the rejections of claims 1-8, 10, 14-18 over Jachowski in view of McHugh are maintained.
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 1-5, 16-20 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by U.S. Patent Application Publication No. 2016/0087186 A1, published March 24, 2016 (“Burak”), of record.
Burak discloses in Fig. 9 and the corresponding description:
Claims 1 and 16
A microacoustic filter (Fig. 9C, annotated below, device 900C, ¶¶80-84), comprising:
a piezoelectric layer (930) having a crystalline structure operative to laterally excite a plate mode (¶¶52, 75, 80; Burak teaches using the same piezoelectric layer/material having a crystalline structure operative to laterally excite a plate mode, ¶75 “two Lamb modes exists,” in all the disclosed resonators and therefore teaches this limitation.);
an electrode structure (831, 835, 841, 845) disposed adjacent a first surface (Fig. 9C, as annotated) of the piezoelectric layer (930);
a first temperature coefficient of frequency (TCF) compensation layer (support frame 960, ¶42 “support frame is formed of dielectric materials”) disposed on the first surface of the piezoelectric layer between the electrode structure and the piezoelectric layer; and
a second TCF compensation layer (support frame 950) disposed on a second surface of the piezoelectric layer opposite to the first surface.
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Claims 2 and 17
further comprising a substrate (205), wherein the electrode structure (831, 835, 841, 845) is between the substrate (205) and the first TCF compensation layer (960).
Claims 3 and 18
further comprising a dielectric under-layer (¶¶53, 80, a dielectric planarization layer) disposed between the electrode structure (831, 835, 841, 845) and the substrate (205).
Claims 4-5
further comprising an interstitial dielectric material (833, 834), wherein:
the electrode structure comprises electrode fingers (831, 841) disposed on the dielectric under-layer (¶¶53, 80, a dielectric planarization layer) and extending in a first direction (Fig. 8 showing the direction of the fingers); and
the interstitial dielectric material (833, 934) is disposed on the dielectric under-layer between the electrode fingers in a second direction orthogonal to the first direction (Fig. 8).
Claim 19
further comprising forming a cavity (airgaps 961-964, ¶¶43, 82-83) formed between the first TCF compensation layer (960) and the electrode structure (831, 841).
Claim 20
A microacoustic filter (Fig. 9C, device 900C, ¶¶80-84) comprising:
a piezoelectric layer (930) having a crystalline structure operative to laterally excite a plate mode (¶¶52, 75, 80; Burak teaches using the same piezoelectric layer/material having a crystalline structure operative to laterally excite a plate mode, ¶75 “two Lamb modes exists,” in all the disclosed resonators and therefore teaches this limitation.);
a first dielectric layer (support frame 960) disposed on a first surface of the piezoelectric layer;
a second dielectric layer (support frame 950) disposed on a second surface of the piezoelectric layer opposite to the first surface; and
an electrode structure (845, 831, 841, 835) disposed on a carrier stack (substrate 205) and spaced from the piezoelectric layer (930) by a gap (airgaps 961-964).
Claim Rejections - 35 USC § 103
Claims 1-8, 10, 14-18 are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Patent Application Publication No. 2023/0283256 A1, published Sep. 7, 2023 (“Jachowski”) in view of U.S. Patent Application Publication No. 2022/0231658 A1, published July 21, 2022 (“McHugh”), both of record.
Jachowski discloses in Figs. 1-5, 10 and the corresponding description:
Claims 1 and 16
A microacoustic filter (Fig. 5, filter 500 using XBARs, ¶54), comprising:
a piezoelectric layer (Fig. 2C, piezoelectric plate 110) having a crystalline structure operative to laterally excite a plate mode (Fig. 4, ¶51-52, XBARs use a bulk shear mode, a type of a plate mode, as their primary acoustic mode);
an electrode structure (Fig. 2C, fingers 238c-d) disposed adjacent a first surface (back-side surface 114) of the piezoelectric layer (110);
a second TCF compensation layer (front-side dielectric layer 212) disposed on a second surface (front-side surface 112) of the piezoelectric layer (110) opposite to the first surface (114) (¶¶44-47).
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Jachowski does not disclose a first temperature coefficient of frequency (TCF) compensation layer disposed on the first surface of the piezoelectric layer between the electrode structure and the piezoelectric layer.
However, McHugh, in the same field of endeavor and the same XBAR technology, teaches to dispose a decoupling dielectric layer between the IDT fingers and the piezoelectric layer (¶¶41-42, “decoupling dielectric layer may be silicon dioxide, which provides an important secondary benefit of lowering the temperature coefficient of frequency (TCF) of the XBAR”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device of Jachowski by having a TCF compensation layer disclosed in McHugh disposed on the first surface of the piezoelectric layer between the electrode structure and the piezoelectric layer for the benefit of lowering the TCF of the XBAR, as taught by McHugh (¶42).
Regarding claim 16, Jachowski in view of McHugh discloses methods of manufacturing the claimed microacoustic filter (Jachowski, Fig. 10; ¶¶77-88; McHugh, Fig. 9, ¶¶ 56-78).
Jachowski in view of McHugh discloses:
Claims 2 and 17
further comprising a substrate (Jachowski, Fig. 3A-B, substrate 320; ¶48), wherein the electrode structure (Fig. 2C, fingers 238c-d) is between the substrate (320) and the first TCF compensation layer (the decoupling layer of McHugh disposed on 114).
Claims 3 and 18
further comprising a dielectric under-layer (Jachowski, Fig. 2C, portions of back-side dielectric layer 214 disposed on fingers 238c-d, as annotated) disposed between the electrode structure and the substrate (¶46).
Claim 4
further comprising an interstitial dielectric material (Fig. 2C, portions of back-side dielectric layer 214 disposed between fingers 238c-d, as annotated), wherein:
the electrode structure comprises electrode fingers (238c-d) disposed on the dielectric under-layer (as annotated) and extending in a first direction (Fig. 1, IDT fingers extend parallel to the piezolayer along B-B); and
the interstitial dielectric material (as annotated) is disposed on the dielectric under-layer between the electrode fingers in a second direction orthogonal to the first direction (Fig. 1, along A-A; ¶38).
Jachowski teaches that “both of the front-side and back-side dielectric layers 212, 214 may be formed of multiple layers of two or more materials” (¶38). Jachowski therefore teaches the interstitial dielectric material (first material of 214) is disposed on the dielectric under-layer (second material of 214).
Claim 5
the first direction is parallel to the first surface of the piezoelectric layer (Fig. 1, IDT fingers extend parallel to the piezolayer along B-B); and
each of the interstitial dielectric material and the electrode fingers have a first thickness orthogonal to the first surface of the piezoelectric layer (Fig. 2C, back-side layer 214 and electrode fingers 238c-d each has a thickness, ¶47). This limitation does not appear to require that the thickness of the interstitial dielectric material be equal to the thickness of the electrode fingers. To the extent it does, Jachowski teaches to planarize the surface of the front-side dielectric layer, which makes each of the interstitial dielectric material and the electrode fingers having an equal first thickness (Fig. 2D, ¶37). In that modification, “a thin layer of dielectric material having a thickness tp” (¶47) used to “seal and passivate the fingers” would read on the claimed dielectric under-layer.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use the well-known technique of planarization to improve a similar device (the embodiments of Fig. 2C) in the same way. MPEP 2143.I.D.
Claims 6-8
further comprising a first passivation layer disposed on the [claim 6: second; claim 7: first] TCF compensation layer (McHugh, passivation and tuning layer 755, Fig. 9, step 950; ¶¶43, 49-51, 70, 74). McHugh teaches that the “passivation/tuning dielectric layer may cover the entire surface of the filter” (¶70), and therefore discloses these limitations. Jachowski and McHugh also teach using silicon nitride (Si3N4) as a dielectric material, as required by claim 8 (Jachowski, ¶49; McHugh, ¶¶31, 65).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device of Jachowski by having a silicon nitride passivation layer disposed on over the first and second TCF compensation layers for the benefit of sealing the surface of the device, as taught by McHugh (¶43).
Claim 10
wherein the first TCF compensation layer has a thickness orthogonal to the first surface of the piezoelectric layer in a range of five (5) to forty (40) nanometers (nm) (McHugh, Figs. 5-6, ¶¶45-47, 64; claim 19). McHugh teaches the ratio of the decoupling (first TCF compensation) layer thickness to the piezoelectric plate thickness to be greater than or equal to 0.02 (¶47). The thickness of the piezoelectric plate disclosed in Jachowski ranges from 100nm to 1500nm (¶36) and in McHugh from 300 to 1000 nm (¶38, 64), which means Jachowski in view of McHugh teaches the first TCF compensation layer thickness is in the range from 2 to 30 nm, as required by the claim. In addition, McHugh discloses that the decoupling layer thickness may range from zero to the thickness of the piezoelectric plate (Claim 19).
Claim 14
wherein: the first direction of the electrode fingers of the electrode structure is parallel to a second axis that is perpendicular to a first axis;
a third axis is perpendicular to the first axis and the second axis;
an orientation of the first axis, the second axis, and the third axis is relative to the crystalline structure of the piezoelectric layer as defined by Euler angles lambda, mu, and theta; and
the piezoelectric layer comprises lithium niobate (Jachowski, ¶27; McHugh, ¶¶37) with the Euler angle lambda being approximately 0°, the Euler angle mu being approximately 32.5°, and the Euler angle theta being approximately 0°, or at least one symmetrical equivalent thereof (McHugh, ¶¶37).
While Jachowski is silent on the Euler angles used in its devices, McHugh teaches using lithium niobate rotated Y-cut with Euler angles 0°, 30°-38°,0° (¶37).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the device of Jachowski by having the Euler angle lambda being approximately 0°, the Euler angle mu being approximately 32.5°, and the Euler angle theta being approximately 0° for the benefit of higher electromechanical coupling, as taught by McHugh (¶37).
Claim 15
The microacoustic filter of claim 1 integrated into a device selected from the group consisting of: a set-top box; an entertainment unit; a navigation device; a communications device; a fixed location data unit; a mobile location data unit; a global positioning system (GPS) device; a mobile phone; a cellular phone; a smartphone; a session initiation protocol (SIP) phone; a tablet; a phablet; a server; a computer; a portable computer; a mobile computing device; a wearable computing device; a desktop computer; a personal digital assistant (PDA); a monitor; a computer monitor; a television; a tuner; a radio; a satellite radio; a music player; a digital music player; a portable music player; a digital video player; a video player; a digital video disc (DVD) player; a portable digital video player; an automobile; a vehicle component; an avionics system; a drone; and a multicopter (Jachowski, ¶4, the disclosed microacoustic filters can be used in “cellular base stations, mobile telephone and computing devices, satellite transceivers and ground stations, IoT (Internet of Things) devices, laptop computers and tablets, fixed point radio links, and other communications systems”).
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Jachowski in view of McHugh and further in view of U.S. Patent Application Publication No. 2016/0126930 A1, published May 5, 2016 (“Zou”).
Regarding claim 9, Jachowski in view of McHugh discloses all the limitations, except “the first TCF compensation layer and the second TCF compensation layer each comprise a layer of carbon-doped silicon dioxide (SiO2C).”
Zou, in the same field of endeavor, teaches using carbon doped silicon dioxide as dielectric material (¶¶56, 80, 127, 142, 161, 221).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to substitute the dielectric materials disclosed in Jachowski and McHugh for carbon-doped silicon dioxide (SiO2C) disclosed in Zou as a simple substitution of one known dielectric element for another to obtain predictable results. MPEP 2143.I.B.
Allowable Subject Matter
Claims 11-13 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter: applicant’s amendment of claim 11 overcomes the closest prior art reference of Burak, of record, by requiring the feature of "the cavity is between the first TCF compensation layer and the electrode structure in the third direction," in combination with the remaining limitations of the claim. Claims 12-13 are allowable as dependent on the allowable claim 11.
Conclusion
THIS ACTION IS MADE FINAL. 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 VICTOR COLE, telephone number (571) 272-4686. The examiner can be reached Monday-Friday, 9AM-5PM ET.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, ANDREA LINDGREN BALTZELL, can be reached at (571) 272-5918. The fax phone number for the organization where this application or proceeding is assigned is (571) 273-8300.
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/VICTOR COLE/
Examiner, Art Unit 2843
/ANDREA LINDGREN BALTZELL/Supervisory Patent Examiner, Art Unit 2843
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