Bulk acoustic wave filter structure with conductive bridge forming electrical loop with an electrode

Patent metadata

Field	Value
Publication number	US-2025062743-A1
Application number	US-202418939706-A
Country	US
Kind code	A1
Filing date	Nov 7, 2024
Priority date	Oct 26, 2020
Publication date	Feb 20, 2025
Grant date	—

Abstract

Disclosed is a Bulk Acoustic Wave (BAW) filter structure with a conductive bridge forming an electrical loop with an electrode for reduced electrical losses. In exemplary aspects disclosed herein, the BAW filter structure includes a transducer with electrodes, a piezoelectric layer between the electrodes, and at least one conductive bridge offset from at least a portion of one of the electrodes by an insulating volume. The conductive bridge forms a first electrical loop between a medial end and a distal end of the electrode. Such a configuration reduces electrical resistance, heat resistance, and/or ohmic losses for improved electrical loss of the BAW filter structure.

First claim

What is claimed is:

1 . A bulk acoustic wave (BAW) filter structure, comprising:
a substrate; at least one transducer over the substrate, the at least one transducer comprising:
a first electrode comprising a first electrical medial end and a first electrical distal end;
a second electrode;
a piezoelectric layer between the first electrode and the second electrode; and
a first conductive bridge offset from at least a portion of the first electrode by a first insulating volume;
a first Bragg reflector positioned proximate the first electrode, the first Bragg reflector comprising a proximate metallic layer; wherein the first conductive bridge comprises metallic vias extending between the first electrode and the proximate metallic layer of the first Bragg reflector; and wherein the first conductive bridge is electrically connected to the first electrical medial end and the first electrical distal end to form a first electrical loop between the first electrical medial end and the first electrical distal end of the first electrode.

2 . The BAW filter structure of claim 1 , wherein the first electrode is a top electrode and the second electrode is a bottom electrode.

3 . The BAW filter structure of claim 1 , wherein the first electrode is a bottom electrode and the second electrode is a top electrode.

4 . The BAW filter structure of claim 1 , wherein the first conductive bridge comprises:
a span portion; a first medial conductive via electrically connecting the span portion to the first electrical medial end of the first electrode; and a first distal conductive via electrically connecting the span portion to the first electrical distal end of the first electrode.

5 . The BAW filter structure of claim 4 , wherein the first conductive bridge further comprises first side conductive vias extending between the first medial conductive via and the first distal conductive via to enclose the first insulating volume between the span portion and the first electrode.

6 . The BAW filter structure of claim 1 , wherein the first conductive bridge comprises:
a span portion; peripheral conductive vias enclosing a second insulating volume; and internal conductive vias within the second insulating volume enclosed by the peripheral conductive vias.

7 . The BAW filter structure of claim 1 , wherein the first insulating volume comprises an air cavity.

8 . The BAW filter structure of claim 1 , wherein the first insulating volume comprises at least a portion of the first Bragg reflector.

9 . A bulk acoustic wave (BAW) filter structure, comprising:
a substrate; a first medial via; and at least one transducer over the substrate, the at least one transducer comprising:
a first electrode comprising a first electrical medial end and a first electrical distal end, a first active region portion, a first medial via portion external to the first active region portion and aligned with the first medial via, and a first distal via portion within the first active region portion and aligned with a first distal via;
a second electrode;
a piezoelectric layer between the first electrode and the second electrode;
a first conductive bridge offset from at least a portion of the first electrode by a first insulating volume; and
wherein the first conductive bridge is electrically connected to the first electrical medial end and the first electrical distal end to form a first electrical loop between the first electrical medial end and the first electrical distal end of the first electrode, the first conductive bridge including the first medial via.

10 . The BAW filter structure of claim 9 , wherein the first electrode is a top electrode and the second electrode is a bottom electrode.

11 . The BAW filter structure of claim 9 , wherein the first electrode is a bottom electrode and the second electrode is a top electrode.

12 . The BAW filter structure of claim 9 , wherein the first conductive bridge comprises:
a span portion; a first distal conductive via electrically connecting the span portion to the first electrical distal end of the first electrode; and wherein the first medial via electrically connects the span portion to the first electrical medial end of the first electrode.

13 . The BAW filter structure of claim 12 , wherein the first conductive bridge further comprises first side conductive vias extending between the first medial via and the first distal conductive via to enclose the first insulating volume between the span portion and the first electrode.

14 . The BAW filter structure of claim 9 , wherein the first conductive bridge comprises:
a span portion; peripheral conductive vias enclosing a second insulating volume; and internal conductive vias within the second insulating volume enclosed by the peripheral conductive vias.

15 . The BAW filter structure of claim 9 , wherein the first insulating volume comprises an air cavity.

16 . The BAW filter structure of claim 9 , wherein the first insulating volume comprises at least a portion of a first Bragg reflector.

17 . A bulk acoustic wave (BAW) filter structure, comprising:
a substrate; and at least one transducer over the substrate, the at least one transducer comprising:
a first electrode comprising a first electrical medial end and a first electrical distal end wherein the first electrode further comprises a first active region portion, a first medial via portion external to the first active region portion and aligned with a first medial via, and a first distal via portion external to the first active region portion and aligned with a first distal via, the first medial via portion being a greater size than the first distal via portion;
a second electrode;
a piezoelectric layer between the first electrode and the second electrode;
a first conductive bridge offset from at least a portion of the first electrode by a first insulating volume; and
wherein the first conductive bridge is electrically connected to the first electrical medial end and the first electrical distal end to form a first electrical loop between the first electrical medial end and the first electrical distal end of the first electrode, the first conductive bridge including the first medial via.

18 . The BAW filter structure of claim 17 , wherein the first electrode is a top electrode and the second electrode is a bottom electrode.

19 . The BAW filter structure of claim 17 , wherein the first electrode is a bottom electrode and the second electrode is a top electrode.

20 . The BAW filter structure of claim 17 , wherein the first insulating volume comprises at least a portion of the first Bragg reflector.

Assignees

• Qorvo Us Inc

Inventors

• Yusuf Yazid
• Modarres-Zadeh Mohammad J
• Tag Andreas
• Stokes Paul
• Aigner Robert
• Fattinger Gernot

Classifications

• H03H9/02086

  Means for compensation or elimination of undesirable effects · CPC title

• H03H9/132

  characterized by a particular shape · CPC title

• H03H9/13

  for networks consisting of piezoelectric or electrostrictive materials (for networks using surface acoustic waves H03H9/145) · CPC title

• H03H9/54

  comprising resonators of piezoelectric or electrostrictive material (comprising resonators using surface acoustic waves H03H9/64) · CPC title

• H03H9/17

  having a single resonator (crystal tuning forks H03H9/21) · CPC title