JPH10115527A - Resonator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve detection sensitivity and make a resonator compact by arranging an electrostatic impressing means for impressing an electrostatic bending tension to a vibration body composed of a weight part and a beam to face the vibrating body via a gap. SOLUTION: An electrostatic impressing means for impressing an electrostatic attraction 15 is arranged to face via a gap 9 a vibrating body 10 formed of a weight part 2 fixed at both ends thereof and a beam 3 by dry etching of a silicon substrate 1 or the like manner. The electrostatic impressing means is constituted of a conductive layer 12 and connected to a conductive pad 14 via a conductive pattern 13. A d.c. voltage is applied to the conductive layer 12 via the conductive pad 14, thereby impressing a force attracting the vibrating body 10 opposed to the conductive layer 12 towards the substrate 1 by an electrostatic attraction. A resonant frequency of the vibrating body is accordingly agreed with a resonant frequency at the design stage. Since the electrostatic attraction is adjusted and the resonant frequency of the vibrating body 10 is adjusted to agree with the resonant frequency set beforehand at the design stage, the resonator 10 is enhanced in sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resonator such as a gyro.

[0002]

2. Description of the Related Art FIG. 3 is a perspective view of a conventional resonator. The resonator 16 is a microelement resonator manufactured using a conventional silicon micromachining technology or the like.
It is 16. Referring to FIG. 1, a nitride film 7 and a polysilicon film 5 are formed on a silicon substrate 1. A vibrating body 10 composed of the beam 3 is formed.

[0003] On both sides of the weight portion 2 at the center of the vibrating body 10, a comb-shaped electrode 6B is formed outwardly in the horizontal direction (perpendicular to the beam 3), and faces the comb-shaped electrode 6B. At the position, that is, at the position on both sides of the polysilicon film 5, the comb-shaped electrode 6 </ b> A
B are arranged so as to mesh with each other. These comb-shaped electrodes 6
Drive conductor layers 11A and 11B are connected to A and 6B, respectively, and are connected to external electrode pads (not shown) via conductor patterns (not shown) to form the exciter 4. When an AC voltage is applied to the driving conductor layers 11A and 11B of the exciter 4, an electrostatic force is generated between the comb-shaped electrodes 6A and 6B, and the vibrating body 10 composed of the weight 2 and the beam 3 is caused by the electrostatic force. It vibrates in the lateral direction of F (in the direction perpendicular to the beam 3).

[0004] Comb-shaped electrodes 6A, 6B of the resonator 16 having the above configuration.
Is driven to vibrate the vibrating body 10 composed of the weight 2 and the beam 3 in the lateral direction, and when the resonator 16 is rotated about the Z axis as a rotation axis, a Coriolis force is generated in a direction perpendicular to the plane of FIG. Then, this Coriolis force is applied to the vibrating body 10 composed of the weight 2 and the beam 3, and the vibrating body 10 vibrates in the direction of the Coriolis force. By measuring an electric signal corresponding to the magnitude of the vibration amplitude due to the Coriolis force of the vibrating body 10 at this time, for example, the magnitude of the angular velocity of rotation is detected.

[0005]

When the resonator 16 is manufactured, the frequency in the direction of the Coriolis force (perpendicular to the paper surface) of the vibrating body 10 is set to the resonance frequency in the design stage in advance, and the vibrating body 16 is set. The shape, size, weight, etc. of 10 are designed and manufactured so as to be at the resonance frequency.
The weight or the like is often not produced as designed due to the processing accuracy of the silicon micromachining technology, and the resonance frequency of the vibrating body 10 often deviates from the designed frequency. If the vibration of the vibrating body 10 is in a resonance state, the amplitude is dramatically increased by the value of Q (Quality Factor) due to the structure. However, when the frequency is shifted, the amplification is hardly caused, and the sensitivity of the resonator is remarkably increased. There is a problem of lowering.
For this reason, it is necessary to trim the weight portion 2 and the beam 3 by, for example, troublesome machining or the like, and adjust the resonance frequency of the vibrating body 10 to a design frequency.

However, since the resonator 16 is a fine resonator 16 manufactured by applying a silicon micromachining technique, a minute trimming adjustment necessary for obtaining a desired resonance frequency by using machining is used. Even if an attempt is made to trim the portion, it is almost impossible to cut the fine weight portion 2 or the beam 3 into a desired size, shape, weight, etc. from the viewpoint of processing accuracy by complicated machining. Therefore, it was extremely difficult to adjust the resonance frequency of the resonator 16 to the set value.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an extremely small-sized resonator which does not require troublesome trimming processing, has good detection sensitivity, and has a good detection sensitivity. It is in.

[0008]

The present invention is configured as follows to achieve the above object. That is, the resonator of the present invention has a weight portion arranged in a floating state on the substrate, a beam supporting the weight portion from both sides, and vibrating the weight portion in a direction orthogonal to the length direction of the beam. A resonator having an exciter, wherein electrostatic applying means for applying an electrostatic bending tension to the vibrating body composed of the weight portion and the beam is provided opposite to the vibrating body via a gap. Have been.

In the present invention, an electrostatic applying means for applying an electrostatic force is provided on a vibrating body comprising a weight portion and a beam so as to face the vibrating body with a gap therebetween. By driving this electrostatic application means,
When an electrostatic force is applied to the vibrating body, the vibrating body is pulled toward the electrostatic application unit, and the direction of the vibration body decreases. Therefore, by controlling the electrostatic force of the electrostatic application means, the vibrating body is adjusted to a desired resonance frequency, and the sensitivity of the resonator is increased.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a resonator according to this embodiment. In the description of the present embodiment, the same reference numerals are given to the same names as those in the conventional example, and detailed description thereof will be omitted. The resonator 16 of the present embodiment is a fine element resonator manufactured using a silicon micromachining technique or the like, similarly to the conventional example.

In the resonator 16 of this embodiment, the vibrating body 10 composed of the weights 2 and the beams 3 fixed to both ends of the silicon substrate 1 is formed by dry etching or the like as in the conventional example. On both sides of 10, there are provided exciters 4 using the electrostatic force of the comb-shaped electrodes 6 </ b> A and 6 </ b> B that vibrate the weight 2 in a direction perpendicular to the length direction of the beam 3.

The characteristic feature of the resonator 16 of this embodiment is that the vibrator 10 composed of the weights 2 and the beams 3 fixed at both ends and formed by dry etching of the silicon substrate 1 is shown in FIG. As shown in (1), the electrostatic applying means for applying the electrostatic attractive force 15 is arranged to face the vibrating body 10 with the gap 9 therebetween. This electrostatic application means is composed of a conductive layer 12 and is connected to a conductive pad 14 via a conductive pattern 13 as shown in FIG.

FIG. 2 shows a manufacturing process of the resonator of this embodiment. First, as shown in FIG. 2A, a nitride film 7 is formed on the outer peripheral side on the silicon substrate 1, and a central portion on the substrate 1 is formed as an electrostatic application means doped with phosphorus P or boron B. Of the conductive layer 12 is formed. This conductive layer 12
As shown in FIG. 2B, a sacrificial layer 8 such as an oxide film is formed over the nitride film 7 on the outer peripheral side. Then
As shown in FIG. 2C, a polysilicon film 5 is formed on the nitride film 7 and the sacrificial layer 8, and as shown in FIG. 2D, the sacrificial layer 8 is removed by, for example, dry etching. Then, the weight 2 serving as a vibrating body is attached to the substrate 1 via the gap 9.
The resonator 16 is fabricated by being arranged opposite to the conductive layer 12 while floating.

The resonator 16 of the present embodiment does not require trimming of the vibrating body 10, and applies a DC voltage to the conductive layer 12 via the conductive pad 14 as shown in FIG. By applying a force to pull the vibrating body 10 on the opposing surface toward the substrate 1 by electrostatic attraction, the vibrating body 10 is pulled with a larger force displacing in the direction of the substrate 1 and displaced in the direction opposite to the substrate side. Sometimes the pulling force is small. With this force, the resonance frequency of the vibrator can be adjusted to the resonance frequency at the design stage. Therefore, the sensitivity of the resonator 16 can be enhanced by adjusting the electrostatic attractive force by the electrostatic application means and adjusting the resonance frequency of the vibrating body 10 to be the resonance frequency set in advance in the design stage.

By driving the exciter 4 of the resonator 16, the vibrating body 10 vibrates in a direction (lateral direction) perpendicular to the length of the beam 3,
When rotated about the Z axis as a rotation axis, a Coriolis force is generated in a direction perpendicular to the plane of FIG. 1, and this Coriolis force is applied to the vibrating body 10, and the vibrating body 10 oscillates in the direction of the Coriolis force. By measuring the magnitude of this amplitude, the angular velocity is detected as in the conventional case.

According to this embodiment, the conductive layer 12 as an electrostatic application means for applying an electrostatic attraction 15 to the vibrating body 10 composed of the weight 2 and the beam 3 is interposed between the vibrating body 10 and the gap. Since it is arranged opposite, by adjusting the electrostatic attractive force 15, the resonance frequency that vibrates in the vertical direction of the vibrating body 10 is set in the design stage in advance even for the fine resonator 16 created by the silicon micromachining technology It can be adjusted to the resonance frequency. That is, by adjusting the resonance frequency of the vibrating body to vibrate in the vertical direction to a frequency close to the driving frequency of vibrating in the horizontal direction, the vibration in the vertical direction due to Coriolis force generated at the same frequency as the driving frequency is caused by resonance. Increased by amplification. As a result, the resonator 16 can detect angular velocity with high sensitivity and high accuracy, for example, irrespective of errors caused in the manufacturing process and changes in the use environment.

The present invention is not limited to the above embodiment, but can adopt various embodiments. For example, in the above embodiment, the weight 2 and the beam 3 are floated on the substrate 1.
Although the vibrating body 10 is fixed at both ends, the vibrating body 10 may be of a one-side fixed type (a cantilever type).

Further, in the above embodiment, the gyro resonator has been described, but the resonator of the present invention can be used in other fields other than the gyro.

Furthermore, in the above embodiment, the conductive layer 12 as the electrostatic applying means is provided on the substrate 1 side located below the vibrating body 10, but the conductive layer 12 as the electrostatic applying means is provided.
May be provided above the vibrating body 10 with a gap therebetween.

[0020]

According to the present invention, the electrostatic force is applied to the vibrating body consisting of the weight and the beam by providing the electrostatic applying means for applying an electrostatic force to the vibrating body with a gap therebetween. By doing so, even a fine resonator manufactured by silicon micromachining technology can be adjusted to the desired resonance frequency, and this resonator is not subject to errors caused in the manufacturing process and changes in the use environment Thus, it is possible to detect, for example, angular velocity with high sensitivity and high accuracy, for example.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a resonator according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a manufacturing process of the resonator of the embodiment.

FIG. 3 is an explanatory diagram of a conventional resonator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Weight part 3 Beam 4 Exciter 5 Polysilicon film 7 Nitride film 10 Vibration body 12 Conductive layer as electrostatic applying means 15 Electrostatic attraction between weight part, beam and electrostatic applying means

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kazufumi Moriya 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Stock Company Murata Manufacturing Co., Ltd. (72) Tomoho Hasegawa 2-26-10 Tenjin Nagaokakyo-city, Kyoto Stock Murata Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. A vibrating body having a weight portion floating on a substrate and beams supporting the weight portion from both sides, and vibrating the vibrating body in a direction orthogonal to its length direction. A resonator comprising: an exciter to be driven; and an electrostatic applying means arranged opposite to the vibrating body with an interval therebetween, and applying electrostatic attraction to the vibrating body to adjust a resonance frequency of the vibrating body.