US 12,506,460 B2Granted

Acoustic wave device

AssigneeMurata Manufacturing Co., Ltd.

InventorSho Nagatomo

Life of this patent

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Abstract

An IDT electrode includes first and second busbar electrodes opposed to each other, first and second electrode fingers extending respectively from the first and second busbar electrodes on a piezoelectric substrate. The first busbar electrode and a tip end of the second electrode finger are opposed to each other with a gap therebetween, and bottom surfaces of the first and second busbar electrodes are opposed to each other with a first gap therebetween. The first and second busbar electrodes respectively include portions opposed to each other with a second gap shorter than the first gap therebetween on the top surface side. In a first area located between a first side surface and a second side surface, a second area located between the piezoelectric substrate and the first busbar electrode or the second electrode finger includes a hollow portion.

Claims20

Dependent claims

An acoustic wave device comprising:

a piezoelectric substrate;
and
an IDT electrode on the piezoelectric substrate;
wherein
the IDT electrode includes:
a pair of busbar electrodes opposed to each other;
and
a plurality of electrode fingers;
each of the plurality of electrode fingers is connected at one end portion to one of the pair of busbar electrodes, and is opposed at another end portion to another one of the pair of busbar electrodes with a gap therebetween;
at least one of an opposing surface of at least one of the pair of busbar electrodes and an opposing surface of at least one of the plurality of electrode fingers, the opposing surfaces being opposed to each other with the gap therebetween, is provided with a convex portion projecting toward a gap side from a portion spaced away from the piezoelectric substrate such that a distance of the gap is shorter at the portion spaced away from the piezoelectric substrate compared to at a portion in contact with the piezoelectric substrate;
and
a hollow portion is provided between the convex portion and the piezoelectric substrate.

9 more elements

An acoustic wave device comprising:

a piezoelectric substrate;
and
an IDT electrode on the piezoelectric substrate;
wherein
the IDT electrode includes:
a first busbar electrode and a second busbar electrode opposed to each other;
a first electrode finger extending from the first busbar electrode toward the second busbar electrode;
and
a second electrode finger extending from the second busbar electrode toward the first busbar electrode;
when, in the first busbar electrode and the second electrode finger, a surface on a piezoelectric substrate side is a bottom surface, a surface opposed to the bottom surface is a top surface, and a surface connecting the top surface to the bottom surface is a side surface, a first side surface of the first busbar electrode and a second side surface of the second electrode finger are opposed to each other with a gap therebetween, the first side surface being the side surface on a second electrode finger side, the second side surface being the side surface on a first busbar electrode side;
and
when the gap from a first point, at which the first side surface contacts the piezoelectric substrate, to a second point, at which the second side surface contacts the piezoelectric substrate is a first gap, the gap from a first portion of the first side surface, the first portion being on a top surface side with respect to the first point, to a second portion of the second side surface, the second portion being on the top surface side with respect to the second point, is a second gap having a length shorter than a length of the first gap;
and
in a first area located between the first side surface and the second side surface, a second area located between the piezoelectric substrate and the first busbar electrode or the second electrode finger is provided with a hollow portion.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/953,379Filed 27 Sep 2022 · continuation
Priority: JP 2020-06220231 Mar 2020
Published: US 2023/0018882 A119 Jan 2023
Granted: 23 Dec 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

H03H 9/02818
Of surface acoustic wave devices: means for compensation or elimination of undesirable effects
H03H 9/02566
Characteristics of substrate, e.g. cutting angles: of semiconductor substrates
H03H 9/02724
Grating lines having particular arrangements: comb like grating lines
H03H 9/02992
Of surface acoustic wave devices: details of bus bars, contact pads or other electrical connections for finger electrodes