Bulk acoustic wave resonator filters with integrated capacitors

Patent metadata

Field	Value
Publication number	US-11870422-B2
Application number	US-202017110675-A
Country	US
Kind code	B2
Filing date	Dec 3, 2020
Priority date	Dec 3, 2020
Publication date	Jan 9, 2024
Grant date	Jan 9, 2024

Abstract

A device includes a piezoelectric layer on a substrate and including a portion included in an acoustic resonator, a first conductive layer on the piezoelectric layer and including a first electrode of the acoustic resonator on a first side of resonator portion of the piezoelectric layer, and a second conductive layer on the piezoelectric layer and including a second electrode of the acoustic resonator on a second side of the resonator portion of the piezoelectric layer. An insulating layer is disposed on the second conductive layer and an interconnection metal layer is electrically connected to the second conductive layer or the first conductive layer and has a portion extending onto the insulating layer and overlapping a portion of the second conductive layer to provide a capacitor electrode of a capacitor coupled to the first electrode and/or the second electrode.

First claim

What is claimed:

1. A device comprising:
a piezoelectric layer on a substrate and comprising a portion included in an acoustic resonator;
a first conductive layer on the piezoelectric layer and comprising a first electrode of the acoustic resonator on a first side of resonator portion of the piezoelectric layer;
a second conductive layer on the piezoelectric layer and comprising a second electrode of the acoustic resonator on a second side of the resonator portion of the piezoelectric layer;
an insulating layer on the second conductive layer; and
an interconnection metal layer electrically connected to the second conductive layer or the first conductive layer and having a portion extending onto the insulating layer and overlapping a portion of the second conductive layer to provide a first capacitor electrode of a capacitor disposed laterally adjacent the acoustic resonator, coupled to the first electrode and/or the second electrode and having a portion of the second conductive layer as a second capacitor electrode of the capacitor and a portion of the insulating layer between the first and second capacitor electrodes as a dielectric of the capacitor, wherein the acoustic resonator comprises a first acoustic resonator and a second acoustic resonator coupled in series and wherein the capacitor is coupled across the series combination of the first acoustic resonator and the second acoustic resonator.

2. The device of claim 1 , further comprising a conductive via that electrically connects the interconnection metal layer to the first electrode or the second electrode and wherein the portion of the interconnection metal layer extends onto the insulating layer adjacent a location where the interconnection layer is disposed on and contacts the conductive via.

3. The device of claim 2 , wherein the conductive via passes through the insulating layer and the piezoelectric layer to contact the first electrode.

4. The device of claim 3 , wherein the first capacitor electrode overlaps a portion of the second electrode.

5. The device of claim 2 :
wherein the piezoelectric layer comprises a first portion included in a first acoustic resonator and a second portion included in a second acoustic resonator;
wherein the first electrode overlaps the first and second portions of the piezoelectric layer; and
wherein the second electrode comprises an electrode overlapping the first portion of the piezoelectric layer and an electrode overlapping the second portion of the piezoelectric layer and the capacitor electrode.

6. The device of claim 5 , wherein the capacitor is coupled between an input of the first acoustic resonator and an output of the second acoustic resonator.

7. The device of claim 1 , wherein the capacitor electrode comprises a capacitor electrode of a capacitor coupled between the first and second electrodes of the acoustic resonator.

8. A method comprising:
forming a piezoelectric layer on a substrate;
forming a first conductive layer on a first side of the piezoelectric layer;
patterning the first conductive layer to form a first electrode for an acoustic resonator;
forming a second conductive layer on a second side of the piezoelectric layer;
patterning the second conductive layer to form a second electrode of the acoustic resonator;
forming an insulating layer on the second conductive layer; and
forming an interconnection metal layer electrically connected to the second electrode layer or the first electrode layer and having a portion extending onto the insulating layer and overlapping a portion of the second conductive layer to provide a first capacitor electrode of a capacitor coupled to the first electrode and/or the second electrode, disposed laterally adjacent the acoustic resonator, and having a portion of the second conductive layer as a second capacitor electrode of the capacitor and a portion of the insulating layer between the first and second capacitor electrodes as a dielectric of the capacitor, wherein the acoustic resonator comprises a first acoustic resonator and a second acoustic resonator coupled in series and wherein the capacitor is coupled across the series combination of the first acoustic resonator and the second acoustic resonator.

9. The method of claim 8 , wherein forming the interconnection metal layer is preceded by forming a conductive via electrically connected to the first electrode or the second electrode, wherein forming the interconnection metal layer comprises forming the interconnection layer on the conductive via, and wherein the portion of the interconnection metal layer extends onto the insulating layer adjacent a location where the interconnection layer contacts the conductive via.

10. The method of claim 9 , wherein forming the conductive via comprises forming a conductive via that passes through the insulating layer and the piezoelectric layer to contact the first electrode.

11. The method of claim 10 , wherein the first capacitor electrode overlaps a portion of the second electrode.

12. The method of claim 9 :
wherein the piezoelectric layer comprises a first portion included in a first acoustic resonator and a second portion included in a second acoustic resonator;
wherein the first electrode overlaps the first and second portions of the piezoelectric layer; and
wherein the second electrode comprises an electrode overlapping the first portion of the piezoelectric layer and an electrode overlapping the second portion of the piezoelectric layer and the first capacitor electrode.

13. The method of claim 12 , wherein the capacitor is coupled between an input of the first acoustic resonator and an output of the second acoustic resonator.

14. The method of claim 8 , wherein the capacitor is coupled between the first and second electrodes of the acoustic resonator.

15. A device comprising:
an acoustic resonator comprising a first electrode, a second electrode and a piezoelectric region between the first and second electrodes;
an insulating layer on the second electrode; and
an interconnection metal layer on the acoustic resonator, connected by a via to the first electrode or the second electrode and having a portion extending onto the insulating layer adjacent the via that serves as a first capacitor electrode of a capacitor disposed laterally adjacent the acoustic resonator and having a portion of the second electrode as a second capacitor electrode of the capacitor and a portion of the insulating layer between the first and second capacitor electrodes as a dielectric of the capacitor, wherein the first electrode is formed from a first conductive layer, wherein the second electrode is formed from second conductive layer, wherein the via connects the interconnection metal layer to a portion of the second conductive layer electrically connected to the first electrode and wherein the first capacitor electrode overlaps the portion of the second conductive layer electrically connected to the first electrode.

16. The device of claim 15 , wherein the first electrode is formed from a first conductive layer, wherein the second electrode is formed from a second conductive layer, wherein the via connects the interconnection metal layer to the first conductive layer and wherein the first capacitor electrode overlaps a portion of the second conductive layer.

17. The device of claim 15 , wherein the piezoelectric region is formed from a piezoelectric layer and wherein the via passes through the piezoelectric layer.

Assignees

• Akoustis Inc

Inventors

• Gupta Saurabh
• Bi Zhiqiang
• Mehdizadeh Emad
• Kim Dae Ho
• Patel Pinal

Classifications

• H03H9/542 Primary

  including passive elements (H03H9/545 takes precedence) · CPC title

• H03H3/02

  for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) · CPC title

• H03H9/0561 Primary

  consisting of a multilayered structure · CPC title

• H03H9/173

  Air-gaps · CPC title

• H03H2003/021

  the resonators or networks being of the air-gap type · CPC title