ACOUSTIC WAVE RESONATOR USING MULTILAYER TRANSDUCTION MATERIALS WITH LOW/ZERO COUPLING BORDER REGION

Application No. 18/150,627

• Filed: Jan 05, 2023
• Priority: Jan 11, 2022 — provisional 63/298,251
  • Mar 29, 2022 — provisional 63/324,968
• Examiner: MATA, SARA M
• Art Unit: 2837
• Tech Center: 2800 — Semiconductors & Electrical Systems
• Assignee: Qorvo US Inc.
• OA Round: 2 (Final)

Office Action

Response After Non-Final
This Office action is in response to the amendment filed on 5/14/2026.
Claims 1-24 are pending in the application.
Claims 1-15 and 24 are rejected.
Claims 16-23 are withdrawn.
Claims 13-14 are amended.
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 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.
Response to Arguments
The applicant's arguments filed May 14, 2026 have been fully considered
and are respectfully found persuasive in part and unpersuasive in part.
The applicant argues the following:
[1] Drawing and claim objections have been addressed and should be withdrawn.

[2] Prior art of record fails to teach “the transduction BO section has a first electromechanical coupling coefficient, and the transduction central section has a second electromechanical coupling coefficient, which is larger than the first electromechanical coupling coefficient of the transduction BO section” in Claims 1 and 24.

Regarding [1], the examiner respectfully agrees and the drawing and claim objections raised in the most recent office action are hereby withdrawn.
Regarding [2], the examiner respectfully disagrees because Burak teaches distinct central and edge regions with distinct material properties and functions. First, while the prior art of record does not explicitly disclose the electromechanical coupling coefficient of each region it is clear that the central and edge regions have different electromechanical coupling coefficients. This is clear because one region, the edge region 153 is etched and the central region is not etched and electromechanical coupling coefficients are a function of material thickness. The etching would necessarily alter thickness, and therefore, the electromechanical coupling coefficients as the material thickness would be altered. Second, while the prior art of record does not explicitly disclose that the central region has a larger electromechanical coupling coefficient than the edge region it is clear that the two regions have different electromechanical coupling coefficients and that the central unetched region would have the higher electromechanical coupling coefficient. As previously stated, electromechanical coupling coefficients are a function of material thickness, and therefore, an unetched thicker material would have a higher electromechanical coupling coefficient than and etched thinner material.
DETAILED ACTION
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of AIA 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)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.

Claims 1-15 and 24 are rejected under AIA 35 U.S.C. 102(a)(2) as being
anticipated by Burak et al. (U.S. Publication No. 20230170876; hereinafter “Burak”).
Regarding claim 1, Burak discloses a Bulk Acoustic Wave (BAW) resonator, comprising: a bottom electrode (Fig. 1A, 121); a top electrode structure (Fig. 1A, 137/139/141/143/145/147/149/151); and a multilayer transduction structure (Fig. 1A, 111/109/107/105/158) sandwiched between (Fig. 1A) the bottom electrode (Fig. 1A, 121) and the top electrode structure (Fig. 1A, 137/139/141/143/145/147/149/151), wherein: the multilayer transduction structure (Fig. 1A, 111/109/107/105/158) is composed (Fig. 1A) of a plurality of transduction layers (Fig. 1A, 111/109/107/105/158); at least one of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158; [0087]; [0091]) is formed (Fig. 1A) of a first ferroelectric material (Fig. 1A; [0087]; [0091]), whose polarization (Fig. 1A) varies (Fig. 1A) with an electric field (Fig. 1A; [0156] – “The stress 173 is excited by the oscillating electric field applied via the top acoustic reflector 115 stack of the plurality of top metal electrode layers 137, 139, 141, 143, 145, 147, 149, 151, and the bottom acoustic reflector 113 stack of the plurality of bottom metal electrode layers 119, 121, 123, 125, 127, 129, 131, 133.”) across (Fig. 1A) the first ferroelectric material (Fig. 1A; [0091] – “ScxAl1-xN”); each of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158) includes (Fig. 1A) a transduction border (BO) portion (Fig. 1A, 153 border portion of 111/109/107/105/158) positioned (Fig. 1A) at a periphery (Fig. 1A, periphery 153) of a corresponding transduction layer (Fig. 1A, corresponding layer 111/109/107/105/158) and a transduction central portion (Fig. 1A, central portion of 111/109/107/105/158) surrounded by (Fig. 1A) the transduction BO portion (Fig. 1A, 153 border portion of 111/109/107/105/158), wherein a combination (Fig. 1A, combination 153 border portion of each 111/109/107/105/158) of the transduction BO portion (Fig. 1A, 153 border portion of 111/109/107/105/158) of each of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158) forms (Fig. 1A) a transduction BO section (Fig. 1A, combination 153 border portion of each 111/109/107/105/158) of the multilayer transduction structure (Fig. 1A, 111/109/107/105/158), and a combination (Fig. 1A, combination of central portion of 111/109/107/105/158) of the transduction central portion (Fig. 1A, central portion of 111/109/107/105/158) of each of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158) forms (Fig. 1A) a transduction central section (Fig. 1A, combination of central portion of 111/109/107/105/158) of the multilayer transduction structure (Fig. 1A, 111/109/107/105/158); and the transduction BO section (Fig. 1A, combination 153 border portion of each 111/109/107/105/158) has a first electromechanical coupling coefficient (Fig. 1A, electromechanical coupling coefficient of combination 153 border portion of each 111/109/107/105/158), and the transduction central section (Fig. 1A, combination of central portion of 111/109/107/105/158) has a second electromechanical coupling coefficient (Fig. 1A, electromechanical coupling coefficient of combination of central portion of 111/109/107/105/158), which is larger (Fig. 1A; [0146] – “The etched edge region may, but need not, assist with acoustic isolation of the resonators. The etched edge region may, but need not, help with avoiding acoustic losses for the resonators.” ) than the first electromechanical coupling coefficient (Fig. 1A, electromechanical coupling coefficient of combination 153 border portion of each 111/109/107/105/158) of the transduction BO section (Fig. 1A, combination 153 border portion of each 111/109/107/105/158), wherein the transduction central section (Fig. 1A, combination of central portion of 111/109/107/105/158) is configured to provide (Fig. 1A) a resonance (Fig. 1A, 100 resonance) of the BAW resonator (Fig. 1A, 100).
Regarding claim 2, Burak discloses the BAW resonator of claim 1 wherein the first electromechanical coupling coefficient of the transduction BO section (Fig. 1A, combination 153 border portion of each 111/109/107/105/158) is a zero electromechanical coupling coefficient (Fig. 1A; [0146] – “The etched edge region may, but need not, assist with acoustic isolation of the resonators. The etched edge region may, but need not, help with avoiding acoustic losses for the resonators.” ).
Regarding claim 3, Burak discloses the BAW resonator of claim 1 wherein the first ferroelectric material (Fig. 1A; [0087]; [0091]) used (Fig. 1A) to form (Fig. 1A) the at least one of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158; [0087]; [0091]) has a box-shaped polarization-electric field (P-E) curve (Fig. 1A; [0087]; [0091]; Examiner’s Note: The P-E curve for a ferroelectric is box-shaped.).
Regarding claim 4, Burak discloses the BAW resonator of claim 3 wherein the first ferroelectric material (Fig. 1A; [0091] – “ScxAl1-xN”) is scandium aluminum nitride (ScxAl1-xN) (Fig. 1A; [0091] – “ScxAl1-xN”) and the P-E curve (Fig. 1A; [0091]) of ScxAl1-N (Fig. 1A; [0091] – “ScxAl1-xN”) is dependent (Fig. 1A; [0091]) on a scandium concentration x (Fig. 1A; [0091]).
Regarding claim 5, Burak discloses the BAW resonator of claim 3 wherein the first ferroelectric material (Fig. 1A; [0087]; [0091]) is one of a group consisting of Zirconate Titanate (PZT), Lead titanate (PTO), Hafnium oxide (HfO2), Barium titanate (BTO), Lithium niobate (LiNbO3) (Fig. 1A; [0087]).
Regarding claim 6, Burak discloses the BAW resonator of claim 3 wherein at least one of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158; [0087] – “Lithium Niobate”) is formed (Fig. 1A) of a second ferroelectric material (Fig. 1A; [0087] – “Lithium Niobate), which has a different P-E curve (Fig. 1A; [0087] – “Lithium Niobate”; Examiner’s Note: The P-E curve for SCALN is different from the P-E curve of Lithium Niobate.) compared to (Fig. 1A; [0087]; [0091]) the first ferroelectric material (Fig. 1A; [0087]; [0091] – “ScxAl1-xN”).
Regarding claim 7, Burak discloses the BAW resonator of claim 6 wherein at least one of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158) is formed (Fig. 1A) of a piezoelectric material (Fig. 1A, 111/109/107/105/158; [0087] – “ZnO”), whose polarization does not vary with an electric field (Fig. 1A; Examiner’s Note: The piezoelectric ZnO has a strong covalent bond preventing polarization switching.) across the piezoelectric material (Fig. 1A, 111/109/107/105/158; [0087] – “ZnO”).
Regarding claim 8, Burak discloses the BAW resonator of claim 1 wherein each of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158) is formed (Fig. 1A) of a different ferroelectric material (Fig. 1A; [0087] – “Lithium Niobate…Lithium Tantalate”; [0091] – “ScxAl1-xN”).
Regarding claim 9, Burak discloses the BAW resonator of claim 1 wherein at least one of the plurality of transduction layers at least one of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158) is formed (Fig. 1A) of a piezoelectric material (Fig. 1A, 111/109/107/105/158; [0087] – “ZnO”), whose polarization does not vary with an electric field (Fig. 1A; Examiner’s Note: The piezoelectric ZnO has a strong covalent bond preventing polarization switching.) across the piezoelectric material (Fig. 1A, 111/109/107/105/158; [0087] – “ZnO”).
Regarding claim 10, Burak discloses the BAW resonator of claim 1 wherein the top electrode structure (Fig. 1A, 137/139/141/143/145/147/149/151) comprises a top electrode base (Fig. 1A, 137) over the multilayer transduction structure (Fig. 1A, 111/109/107/105/158) and a BO ring protruding (Fig. 1A, border ring protruding from periphery of 137) protruding (Fig. 1A) from a periphery (Fig. 1A, periphery of 37) of the top electrode base (Fig. 1A, 137), wherein: a region (Fig. 1A, region of 100)of the BAW resonator (Fig. 1A, 100), within which (Fig. 1A) the BO ring (Fig. 1A, border ring protruding from periphery of 137) is located (Fig. 1A) is a BO region (Fig. 1A, location in 100 within which border ring protruding from periphery of 137 is located); and the ferroelectric BO portion (Fig. 1A, 153 border portion of ScxAl1-xN layer) is confined within (Fig. 1A) the BO region (Fig. 1A, location in 100 within which border ring protruding from periphery of 137 is located) and aligned underneath (Fig. 1A) the BO ring (Fig. 1A, border ring protruding from periphery of 137), while the ferroelectric central portion (Fig. 1A, central portion of ScxAl1-xN layer) is not covered (Fig. 1A) by the BO ring (Fig. 1A, border ring protruding from periphery of 137).
Regarding claim 11, Burak discloses the BAW resonator of claim 1 wherein each of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158) has a different thickness (Figs. 1A/1D-E/4H-I; [Abstract]; [0068]).Regarding claim 12, Burak discloses the BAW resonator of claim 1 wherein each of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158) has a same thickness (Fig. 1A; [0175] – “In bulk acoustic SHF or EHF wave resonator 2001A, respective layer thicknesses of the four piezoelectric layer stack may be substantially equal.”).
Regarding claim 13, Burak discloses the BAW resonator of claim 1 further comprising a bottom Bragg reflector (Fig. 1A, 113; [0121]) formed underneath (Fig. 1A) the bottom electrode (Fig. 1A, 121).
Regarding claim 14, Burak discloses the BAW resonator of claim 13 further comprising a top Bragg reflector (Fig. 1A, 115; [0132]) formed over (Fig. 1A) the top electrode structure (Fig. 1A, 137/139/141/143/145/147/149/151).
Regarding claim 15, Burak discloses the BAW resonator of claim 1 wherein the multilayer transduction structure (Fig. 1A, 111/109/107/105/158) further comprises (Fig. 1A) a plurality of internal electrodes (Fig. 1A, 163/161/159), which are alternated (Fig. 1A) with the plurality of transduction layers (Fig. 1A, 111/109/107/105/158).
Regarding claim 24, Burak discloses a system, comprising: a radio-frequency (RF) input circuitry(Figs. 1A/11; Fig. 11, 9515N input circuitry); a RF output circuitry (Figs. 1A/11; Fig. 11, 9515N output circuitry); and a filter circuitry (Figs. 1A/11A; Fig. 11, 9112J/9114J/9116J/9118J), which includes at least one Bulk Acoustic Wave (BAW) resonator (Figs. 1A/11; Fig. 1A, 100; Fig. 11, 9112J/9114J/9116J/9118J; [0433]), connected between the RF input circuitry (Figs. 1A/11; Fig. 11, 9515N input circuitry) and the RF output circuitry (Figs. 1A/11; Fig. 11, 9515N output circuitry), wherein the at least one BAW resonator (Figs. 1A/11; Fig. 1A, 100; Fig. 11, 9112J/9114J/9116J/9118J; [0433]) comprises: a bottom electrode (Fig. 1A, 121); a top electrode structure (Fig. 1A, 137/139/141/143/145/147/149/151); and a multilayer transduction structure (Fig. 1A, 111/109/107/105/158) sandwiched between (Fig. 1A) the bottom electrode (Fig. 1A, 121) and the top electrode structure (Fig. 1A, 137/139/141/143/145/147/149/151), wherein: the multilayer transduction structure (Fig. 1A, 111/109/107/105/158) is composed (Fig. 1A) of a plurality of transduction layers (Fig. 1A, 111/109/107/105/158); at least one of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158; [0087]; [0091]) is formed (Fig. 1A) of a ferroelectric material (Fig. 1A; [0087]; [0091]), which has a box-shaped polarization-electric field (P-E) curve (Fig. 1A; ; [0087]; [0091]; Examiner’s Note: The P-E curve for a ferroelectric is box-shaped.); each of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158) includes (Fig. 1A) a transduction border (BO) portion (Fig. 1A, 153 border portion of 111/109/107/105/158) positioned (Fig. 1A) at a periphery (Fig. 1A, periphery 153) of a corresponding transduction layer (Fig. 1A, corresponding layer 111/109/107/105/158) and a transduction central portion (Fig. 1A, central portion of 111/109/107/105/158) surrounded by (Fig. 1A) the transduction BO portion (Fig. 1A, 153 border portion of 111/109/107/105/158), wherein a combination (Fig. 1A, combination 153 border portion of each 111/109/107/105/158) of the transduction BO portion (Fig. 1A, 153 border portion of 111/109/107/105/158) of each of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158) forms (Fig. 1A) a transduction BO section (Fig. 1A, combination 153 border portion of each 111/109/107/105/158) of the multilayer transduction structure (Fig. 1A, 111/109/107/105/158), and a combination (Fig. 1A, combination of central portion of 111/109/107/105/158) of the transduction central portion (Fig. 1A, central portion of 111/109/107/105/158) of each of the plurality of transduction layers (Fig. 1A, 111/109/107/105/158) forms (Fig. 1A) a transduction central section (Fig. 1A, combination of central portion of 111/109/107/105/158) of the multilayer transduction structure (Fig. 1A, 111/109/107/105/158); and the transduction BO section (Fig. 1A, combination 153 border portion of each 111/109/107/105/158) has a first electromechanical coupling coefficient (Fig. 1A, electromechanical coupling coefficient of combination 153 border portion of each 111/109/107/105/158), and the transduction central section (Fig. 1A, combination of central portion of 111/109/107/105/158) has a second electromechanical coupling coefficient (Fig. 1A, electromechanical coupling coefficient of combination of central portion of 111/109/107/105/158), which is larger (Fig. 1A; [0146] – “The etched edge region may, but need not, assist with acoustic isolation of the resonators. The etched edge region may, but need not, help with avoiding acoustic losses for the resonators.” ) than the first electromechanical coupling coefficient (Fig. 1A, electromechanical coupling coefficient of combination 153 border portion of each 111/109/107/105/158) of the transduction BO section (Fig. 1A, combination 153 border portion of each 111/109/107/105/158), wherein the transduction central section (Fig. 1A, combination of central portion of 111/109/107/105/158) is configured to provide (Fig. 1A) a resonance (Figs. 1A/11; Fig. 1A, resonance of 100; Fig. 11, resonance of 9112J/9114J/9116J/9118J; [0433]) of the BAW resonator (Figs. 1A/11; Fig. 1A, 100; Fig. 11, 9112J/9114J/9116J/9118J; [0433]).

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 extension fee 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 date of this final action.
Any inquiry concerning this communication should be directed to MONICA MATA
whose telephone number is [phone]. The examiner can normally be reached on Monday thru Friday from 7:30 AM to 5:00 PM.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s
supervisor, Dedei Hammond, can be reached on [phone]. The fax phone number for the organization where this application or proceeding is assigned is [phone].
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/MONICA MATA/
Patent Examiner, Art Unit 2837

23 July 2026

/EMILY P PHAM/Primary Examiner, Art Unit 2837

Prosecution Timeline

• Jan 05, 2023: Application Filed
• Mar 03, 2026: Non-Final Rejection mailed — §102
• May 14, 2026: Response Filed
• Jul 28, 2026: Final Rejection mailed — §102 (current)