Acoustic wave device and manufacturing method of acoustic wave device

An acoustic wave device comprising:

• an acoustic wave element including:
• an element substrate;
• a piezoelectric layer on the element substrate;
• a functional electrode on the piezoelectric layer;
• and
• a wiring electrode on the piezoelectric layer and electrically coupled to the functional electrode, in which the element substrate includes an air gap at a position overlapping a portion of the functional electrode in plan view in a stacking direction of the element substrate and the piezoelectric layer;
• a mounting substrate including an external terminal;
• a metal bump coupling the wiring electrode and the external terminal;
• sealing resin sealing the acoustic wave element and the metal bump;
• and
• a different material portion in at least a portion of an outer surface of the element substrate, except a surface of contact with the piezoelectric layer, and made of a material different from a material of the element substrate.

An acoustic wave device comprising:

• an acoustic wave element including:
• an element substrate;
• a piezoelectric layer on the element substrate;
• a functional electrode on the piezoelectric layer;
• and
• a wiring electrode on the piezoelectric layer and electrically coupled to the functional electrode, in which the element substrate is provided with an air gap at a position overlapping a part of the functional electrode in plan view in a stacking direction of the element substrate and the piezoelectric layer;
• a mounting substrate including an external terminal;
• a metal bump coupling the wiring electrode and the external terminal;
• sealing resin sealing the acoustic wave element and the metal bump;
• and
• an uneven portion in at least a portion of an outer surface of the element substrate, except a surface of contact with the piezoelectric layer, and including an uneven surface.

An acoustic wave device comprising:

• an acoustic wave element including:
• an element substrate;
• a piezoelectric layer on the element substrate;
• a functional electrode on the piezoelectric layer;
• and
• a wiring electrode on the piezoelectric layer and electrically coupled to the functional electrode, in which the element substrate includes an air gap at a position overlapping a portion of the functional electrode in plan view in a stacking direction of the element substrate and the piezoelectric layer;
• a mounting substrate including an external terminal;
• a metal bump coupling the wiring electrode and the external terminal;
• sealing resin sealing the acoustic wave element and the metal bump;
• and
• a low acoustic impedance portion in at least a portion of an outer surface of the element substrate, except a surface of contact with the piezoelectric layer, and including a low acoustic impedance layer.

A method of manufacturing an acoustic wave device that includes:

• an acoustic wave element including:
• an element substrate;
• a piezoelectric layer on the element substrate;
• a functional electrode on the piezoelectric layer;
• and
• a wiring electrode on the piezoelectric layer and electrically coupled to the functional electrode, in which the element substrate includes an air gap at a position overlapping a portion of the functional electrode in plan view in a stacking direction of the element substrate and the piezoelectric layer;
• a mounting substrate including an external terminal;
• a metal bump coupling the wiring electrode and the external terminal;
• sealing resin sealing the acoustic wave element and the metal bump;
• and
• an attenuator in at least a portion of an outer surface of the element substrate, except a surface of contact with the piezoelectric layer, and structured to attenuate unwanted emissions, the method comprising:
• forming the attenuator within the element substrate by laser irradiation.

A method of manufacturing an acoustic wave device that includes:

• an acoustic wave element including:
• an element substrate;
• a piezoelectric layer on the element substrate;
• a functional electrode on the piezoelectric layer;
• and
• a wiring electrode on the piezoelectric layer and electrically coupled to the functional electrode, in which the element substrate includes an air gap at a position overlapping a portion of the functional electrode in plan view in a stacking direction of the element substrate and the piezoelectric layer;
• a mounting substrate including an external terminal;
• a metal bump coupling the wiring electrode and the external terminal;
• sealing resin sealing the acoustic wave element and the metal bump;
• and
• an attenuator in at least a portion of an outer surface of the element substrate, except a surface of contact with the piezoelectric layer, and structured to attenuate unwanted emissions, the method comprising:
• forming the attenuator by performing chemical vapor deposition of a SiO2 film.

A method of manufacturing an acoustic wave device that includes:

• an acoustic wave element including:
• an element substrate;
• a piezoelectric layer on the element substrate;
• a functional electrode on the piezoelectric layer;
• and
• a wiring electrode on the piezoelectric layer and electrically coupled to the functional electrode, in which the element substrate includes an air gap at a position overlapping a portion of the functional electrode in plan view in a stacking direction of the element substrate and the piezoelectric layer;
• a mounting substrate including an external terminal;
• a metal bump coupling the wiring electrode and the external terminal;
• sealing resin sealing the acoustic wave element and the metal bump;
• and
• an attenuator in at least a portion of an outer surface of the element substrate, except a surface of contact with the piezoelectric layer, and structured to attenuate unwanted emissions, the method comprising:
• in a process of flip-chip bonding the acoustic wave element that is singulated, onto the mounting substrate, providing the attenuator in, of a pair of major surfaces of the element substrate that are transverse to the stacking direction, another major surface that is opposite to one major surface adjacent to the piezoelectric layer.