TUNING FOLK VIBRATION DEVICE AND METHOD FOR MANUFACTURING THE SAME

Abstract

A tuning folk vibration device includes: a SOI substrate having a substrate, an oxide layer formed above the substrate and a semiconductor layer formed above the oxide layer; a tuning folk type vibration section that is formed by processing the semiconductor layer and the oxide layer and composed of the semiconductor layer; and a driving section for generating flexural vibration of the vibration section, wherein the vibration section includes a support section and two beam sections formed in a cantilever shape with the support section as a base of the beam sections, and the driving section includes a pair of drivers formed on each of the two beam sections, each of the drivers including a first electrode layer, a piezoelectric layer formed above the first electrode layer and a second electrode layer formed above the piezoelectric layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view schematically showing the structure of a tuning folk vibration device in accordance with a first embodiment of the invention.

FIG. 2 is a cross-sectional view taken along lines A-A of FIG. 1.

FIG. 3 is a cross-sectional view schematically showing a step of a method for manufacturing a tuning folk vibration device in accordance with an embodiment of the invention.

FIG. 4 is a cross-sectional view schematically showing a step of the method for manufacturing a tuning folk vibration device in accordance with the embodiment of the invention.

FIG. 5 is a cross-sectional view schematically showing a step of the method for manufacturing a tuning folk vibration device in accordance with the embodiment of the invention.

Claims

1. A tuning fork vibration device comprising: a SOI substrate having a substrate, an oxide layer formed above the substrate and a semiconductor layer formed above the oxide layer;a tuning fork type vibration section that is formed by processing the semiconductor layer and the oxide layer and composed of the semiconductor layer; anda driving section for generating flexural vibration of the vibration section, wherein the vibration section includes a support section and two beam sections formed in a cantilever shape with the support section as a base of the beam sections, and the driving section includes a pair of drivers formed on each of the two beam sections, each of the drivers including a first electrode layer, a piezoelectric layer formed above the first electrode layer and a second electrode layer formed above the piezoelectric layer.

2. A tuning fork vibration device according to claim 1, wherein the thickness of the vibration section is 20 μm or less.

3. A tuning fork vibration device according to claim 1, wherein the length of the vibration section is 2 mm or less.

4. A tuning fork vibration device according to claim 1, wherein the resonance frequency of the vibration section is at a 32 kHz band.

5. A tuning fork vibration device according to claim 1, wherein the piezoelectric layer is composed of lead zirconate titanate, or solid solution of lead zirconate titanate.

6. A method for manufacturing a tuning fork vibration device the method comprising the steps of: successively forming a first electrode layer, a piezoelectric layer and a second electrode layer above a SOI substrate having a substrate, an oxide layer formed above the substrate and a semiconductor layer formed above the oxide layer;patterning the first electrode layer, the piezoelectric layer and the second electrode layer to form a driving section;patterning the semiconductor layer to form a vibration section; andpatterning the oxide layer to form an opening section below the vibration section,wherein the vibration section is formed to include a support section and two beam sections formed in a cantilever shape with the support section as a base of the beam sections, and the driving section is formed to have a pair of drivers provided on each of the two beam sections, wherein each of the drivers is formed to include a first electrode layer, a piezoelectric layer formed above the first electrode layer and a second electrode layer formed above the piezoelectric layer.