Micro electro mechanical system

Patent metadata

Field	Value
Publication number	US-10145686-B2
Application number	US-201615299772-A
Country	US
Kind code	B2
Filing date	Oct 21, 2016
Priority date	Aug 18, 2008
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

In order to provide a technology capable of suppressing degradation of measurement accuracy due to fluctuation of detection sensitivity of an MEMS by suppressing fluctuation in natural frequency of the MEMS caused by a stress, first, fixed portions 3 a to 3 d are displaced outward in a y-direction of a semiconductor substrate 2 by deformation of the semiconductor substrate 2 . Since a movable body 5 is disposed in a state of floating above the semiconductor substrate 2 , it is not affected and displaced by the deformation of the semiconductor substrate 2 . Therefore, a tensile stress (+σ 1 ) occurs in the beam 4 a and a compressive stress (−σ 2 ) occurs in the beam 4 b . At this time, in terms of a spring system made by combining the beam 4 a and the beam 4 b , increase in spring constant due to the tensile stress acting on the beam 4 a and decrease in spring constant due to the compressive stress acting on the beam 4 b are offset against each other.

First claim

What is claimed is:

1. A micro electro mechanical system comprising a sensor element,
the sensor element including:
a movable body displaceable in a predetermined displacement direction;
a first spring system having a first fixed portion fixed to the substrate, a first turning portion, an elastically deformable first beam connected at one end to the first fixed portion and at another end to the first turning portion, an elastically deformable second beam connected at one end to the first turning portion and at another end to the movable body, and an elastically deformable third beam connected at one end to the first turning portion and at another end to the movable body; and
a second spring system having a second fixed portion fixed to the substrate, a second turning portion, an elastically deformable fourth beam connected at one end to the second fixed portion and at another end to the second turning portion, an elastically deformable fifth beam connected at one end to the second turning portion and at another end to the movable body, and an elastically deformable sixth beam connected at one end to the second turning portion and at another end to the movable body,
wherein the first to sixth beams extend in a perpendicular direction perpendicular to the displacement direction, and
when a straight line passing through a center of the sensor element in the perpendicular direction and extending in the displacement direction is defined as a center line, the first fixed portion and the second fixed portion are disposed on opposite sides with respect to the center line.

2. A micro electro mechanical system comprising:
a substrate;
a movable body displaceable in a predetermined displacement direction;
a first spring system having a first fixed portion fixed to the substrate, a first turning portion, an elastically deformable first beam connected at one end to the first fixed portion and at another end to the first turning portion, an elastically deformable second beam connected at one end to the first turning portion and at another end to the movable body, and an elastically deformable third beam connected at one end to the first turning portion and at another end to the movable body; and
a second spring system having a second fixed portion fixed to the substrate, a second turning portion, an elastically deformable fourth beam connected at one end to the second fixed portion and at another end to the second turning portion, an elastically deformable fifth beam connected at one end to the second turning portion and at another end to the movable body, and an elastically deformable sixth beam connected at one end to the second turning portion and at another end to the movable body,
wherein the first to sixth beams extend in a perpendicular direction perpendicular to the displacement direction, and
when the substrate is deformed, the first fixed portion and the second fixed portion are displaced in opposite directions.

3. A micro electro mechanical system comprising a sensor element,
the sensor element including:
a movable body displaceable in a predetermined displacement direction;
a first spring system having a first fixed portion fixed to the substrate, a first turning portion, an elastically deformable first beam connected at one end to the first fixed portion and at another end to the first turning portion, an elastically deformable second beam connected at one end to the first turning portion and at another end to the movable body, and an elastically deformable third beam connected at one end to the first turning portion and at another end to the movable body; and
a second spring system having a second fixed portion fixed to the substrate, a second turning portion, an elastically deformable fourth beam connected at one end to the second fixed portion and at another end to the second turning portion, an elastically deformable fifth beam connected at one end to the second turning portion and at another end to the movable body, and an elastically deformable sixth beam connected at one end to the second turning portion and at another end to the movable body,
wherein the first to sixth beams extend in a perpendicular direction perpendicular to the displacement direction, and
when a straight line passing through a center of the sensor element in the perpendicular direction and extending in the displacement direction is defined as a center line, the first fixed portion and the second fixed portion are disposed at positions sandwiching the center line.

4. The micro electro mechanical system according to claim 1 , further comprising:
a substrate in which the first fixed portion and the second fixed portion are provided,
wherein when the substrate is deformed, the first fixed portion and the second fixed portion are displaced in opposite directions.

5. The micro electro mechanical system according to claim 1 ,
wherein the second beam and the third beam are provided outside the first beam, and
the fifth beam and the sixth beam are provided outside the fourth beam.

6. The micro electro mechanical system according to claim 1 ,
wherein a number of beams included in the first spring system is equal to a number of beams included in the second spring system.

7. The micro electro mechanical system according to claim 1 ,
wherein the first turning portion is provided outside the first fixed portion with respect to the center line, and the second turning portion is provided inside the second fixed portion with respect to the center line.

8. The micro electro mechanical system according to claim 1 ,
wherein the first spring system further has an elastically deformable seventh beam connected to the first fixed portion and the first turning portion, and
the second spring system further has an elastically deformable eighth beam connected to the second fixed portion and the second turning portion.

9. The micro electro mechanical system according to claim 1 ,
wherein the sensor element is formed on a first semiconductor chip, and
the first semiconductor chip is mounted on an underlayer substrate via an adhesive agent.

10. The micro electro mechanical system according to claim 9 ,
wherein the underlayer substrate is a second semiconductor chip in which an integrated circuit is formed.

11. The micro electro mechanical system according to claim 1 ,
wherein the sensor element is an angular velocity sensor.

Assignees

• Hitachi Ltd
• Hitachi Ltd

Inventors

• Degawa Munenori
• Jeong Heewon

Classifications

• B81B3/0072

  For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers · CPC title

• G01P2015/0814

  for translational movement of the mass, e.g. shuttle type · CPC title

• B81B2203/0109

  Bridges · CPC title

• B81B2201/025

  Inertial sensors not provided for in B81B2201/0235 - B81B2201/0242 · CPC title

• G01P15/0802

  Details · CPC title