Method for fabricating resonator structure and resonator structure

Patent metadata

Field	Value
Publication number	US-11233493-B2
Application number	US-201815934387-A
Country	US
Kind code	B2
Filing date	Mar 23, 2018
Priority date	Apr 6, 2017
Publication date	Jan 25, 2022
Grant date	Jan 25, 2022

Abstract

Methods for manufacturing resonator structures and corresponding resonator structures are described. A first wafer including a first piezoelectric material is singulated and bonded to a second wafer.

First claim

The invention claimed is:

1. A method for manufacturing a coupled resonator structure, comprising:
processing a first wafer to form a processed first wafer comprising a first piezoelectric material;
processing a second wafer to form a processed second wafer comprising a second piezoelectric material, wherein the second piezoelectric material has a lower piezoelectric coupling constant then the first piezoelectric material;
singulating the first wafer to form at least one singulated wafer chip;
bonding the at least one singulated wafer chip to the second wafer to form a joint wafer; and
processing the joint wafer to form a resonator structure comprising a first resonator including the first piezoelectric material and a second resonator including the second piezoelectric material such that the first and second resonators are acoustically coupled with each other.

2. The method of claim 1 , wherein the processing the second wafer comprises forming the second resonator on the second wafer.

3. The method of claim 1 , wherein the second piezoelectric material comprises aluminum nitride or scandium aluminum nitride.

4. A resonator structure, comprising:
a diced first wafer piece comprising a first piezoelectric material; and
a substrate comprising an acoustic termination at a first side thereof,
wherein the diced first wafer piece is bonded to a second wafer piece comprising a second piezoelectric material having a lower piezoelectric coupling constant than the first piezoelectric material, such that the first side of the substrate faces the diced first wafer piece.

5. The method of claim 1 , wherein the processed second wafer comprises an acoustic termination at a first side thereof, and the bonding is performed such that the first side of the second wafer faces the singulated wafer chip.

6. A method for manufacturing a resonator structure, comprising:
processing a first wafer to form a processed first wafer comprising a first piezoelectric material, wherein the processing the first wafer comprises providing a first dielectric layer on the first wafer;
processing a second wafer to form a processed second wafer comprising an acoustic termination at a first side thereof, wherein the processing the second wafer comprises providing a second dielectric layer on the second wafer;
singulating the first wafer to form at least one singulated wafer chip;
bonding the at least one singulated wafer chip to the second wafer such that the first side of the second wafer faces the singulated wafer chip to form a joint wafer, wherein the bonding comprises bonding the first and second dielectric layers; and
processing the joint wafer to form a resonator structure comprising a first resonator including the first piezoelectric material.

7. The method of claim 6 , wherein the acoustic termination comprises a cavity or an acoustic mirror.

8. The method of claim 6 , wherein the acoustic termination is encapsulated in the resonator structure.

9. The method of claim 1 , wherein the first wafer is made of the first piezoelectric material.

10. The method of claim 1 , wherein the first piezoelectric material is monocrystalline.

11. The method of claim 1 , wherein the processing the first wafer comprises depositing a conductive material on the first wafer, at least part of the conductive material forming an electrode of the first resonator.

12. The method of claim 11 , further comprising structuring the conductive material.

13. The method of claim 1 , wherein the first piezoelectric material comprises lithium niobate or lithium tantalate.

14. The method of claim 1 , wherein the processing of the joint wafer comprises electrode deposition, electrode structuring or providing electrode connections.

15. The method of claim 6 , wherein the first and second dielectric layers comprise an oxide.

16. The method of claim 1 , further comprising encapsulating the joint wafer.

17. The method of claim 1 , wherein the processing of the joint wafer comprises thinning the first piezoelectric layer.

Assignees

• Infineon Technologies Ag

Inventors

• Timme Hans-Joerg
• Ahrens Carsten
• Bauder Ruediger

Classifications

• H03H9/02015 Primary

  Characteristics of piezoelectric layers, e.g. cutting angles · CPC title

• H03H9/02086

  Means for compensation or elimination of undesirable effects · CPC title

• H03H3/02 Primary

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

• H03H9/205

  having multiple resonators (crystal tuning forks H03H9/21) · CPC title

• H03H9/17 Primary

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