Murata Manufacturing Co., Ltd.

Naohiro Nodake

Tetsuya Kimura

Hideaki Takahashi

Shin Saijo

Hajime Kando

Sho Nagatomo

Kazunori Inoue

Toshiyuki Fuyutsume

Masahiko Saeki

Yuta Ishii

An acoustic wave device includes a piezoelectric film and an IDT electrode on the piezoelectric film. The IDT electrode includes first and second busbars, at least one first electrode finger, and at least one second electrode finger. When an overlap region is defined as a region in which the first and second electrode fingers overlap each other in an acoustic wave propagation direction, points A, B, C, and D, defined as follows, are all outside the cavity when, at the points A, B, C, and D, xa>about 25 μm, ya>about 25 μm, xb>about 25 μm, yb>about 25 μm, xc>about 25 μm, yc>about 25 μm, xd>about 25 μm, and yd>about 25 μm.

Acoustic wave device

An elastic wave device includes a piezoelectric film made of lithium niobate or lithium tantalate, and a first electrode finger and a second electrode finger opposing each other in a direction intersecting a thickness direction of the piezoelectric film. When an average thickness of the piezoelectric film is d and a distance between centers of the first electrode finger and the second electrode finger is p, d/p is about 0.5 or less. The first electrode finger and the second electrode finger are connected to the first and second bus bars, respectively. The first and second bus bars include corner portions. At least one of corner portions of the first and second bus bars is outside a cavity portion when viewed in plan view.

Elastic wave device and ladder filter

A manufacturing method for a boundary acoustic wave device is provided which includes, an IDT electrode, a first dielectric layer, and a second dielectric layer on a piezoelectric substrate. The first dielectric layer is made of a deposited film. A thickness of the IDT electrode is about 10% or more of &#x3bb;. A difference between a height of the first dielectric layer, measured from an upper surface of the piezoelectric substrate, above a center of an electrode finger of the IDT electrode and a height of the first dielectric layer, measured from the upper surface of the piezoelectric substrate, above a center of a gap between adjacent electrode fingers, i.e., a magnitude of unevenness in an upper surface of the first dielectric layer, is about 5% or less of &#x3bb;.

Method of manufacturing a boundary acoustic wave device

In the boundary acoustic wave device, an IDT electrode, a first dielectric layer, and a second dielectric layer are provided on a piezoelectric substrate. The first dielectric layer is made of a deposited film. A thickness of the IDT electrode is about 10% or more of &#x3bb;. A difference between a height of the first dielectric layer, measured from an upper surface of the piezoelectric substrate, above a center of an electrode finger of the IDT electrode and a height of the first dielectric layer, measured from the upper surface of the piezoelectric substrate, above a center of a gap between adjacent electrode fingers, i.e., a magnitude of unevenness in an upper surface of the first dielectric layer, is about 5% or less of &#x3bb;.

Boundary acoustic wave device and method of manufacturing same

A method for manufacturing a boundary acoustic wave device prevents formation of discontinuous portions in a dielectric film without a significant decrease in the thickness of an IDT when the dielectric film is formed by deposition and without deterioration of electrical characteristics. The method includes the steps of forming an IDT on a piezoelectric substrate, forming a lower dielectric film so as to cover the IDT, conducting a planarizing step so as to smooth the rough surface of the lower dielectric film, and forming an upper dielectric film so as to cover the lower dielectric film of which the rough surface is smoothed.

Growing community of inventors

Nagaokakyo, Japan

Naohiro Nodake