JP2002048553A - Vibrating type gyroscopic sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of reducing the electric cross talk between electrode leads on the drive side and the detection side of a vibrating type gyroscopic sensor and its detection noise. SOLUTION: The electric cross talk between the drive side and the detection side can be reduced by extracting a driving wire and a detecting electrode through the through holes formed on the glass faces of different fixed substrates. The detection noise is reduced and the sensor can be miniaturized by mounting a separately manufactured amplifier on the extracting face side of the detecting electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration type gyro sensor manufactured using a silicon substrate, and more particularly to a driving structure and a detection side electrode in a conductive structure for taking out wiring through a through hole. The present invention relates to a vibration gyro sensor having a configuration in which electrical crosstalk between leads and detection noise are reduced.

[0002]

2. Description of the Related Art As a capacitance-type acceleration sensor, a plurality of pairs of capacitance elements are provided opposite to each other by attaching electrodes to opposing surfaces of a fixed substrate and a flexible substrate. XY
A plane is set, and changes in acceleration in the three-dimensional directions of the X, Y, and Z axes of the Z axis orthogonal to the plane are calculated based on capacitance changes between a plurality of pairs of capacitance elements. There has been proposed a configuration for detecting an error (Japanese Patent Laid-Open Nos. 4-148833 and 4-33).
7431, Japanese Patent Laid-Open No. 5-188079).

[0003] A vibration-type acceleration detector or angular velocity detector constructed and manufactured by a micromachine or the like using a silicon substrate includes a flexible substrate of a vibrator made of a silicon substrate and a fixed substrate such as a glass plate. A bonding substrate is formed by electrostatic bonding (anodic bonding) or the like in which bonding is performed without using an adhesive or a bonded object.

An electrode is attached to each of the opposing surfaces of the fixed substrate and the flexible substrate so as to oppose each other. An extremely narrow space of several μm to several tens μm is set between the substrates. In order to detect a change in the gap between the fixed electrodes and a change in the capacitance generated between the electrodes, it is necessary to draw out a conductive means such as a wiring (electrode lead) connected to the electrodes.

[0005] Further, since the pressure of the air in the narrow space fluctuates depending on the temperature, even a very small amount of air is not negligible for a minute vibrator, and it is desirable to reduce the pressure inside the sensor. However, there has been a problem that the inside of the sensor is easily brought into a state of communication with the outside by the electrode lead or the like, or a special process for sealing is required, resulting in poor productivity.

[0006]

Therefore, by providing a through hole in a fixed substrate such as a glass plate to achieve conduction with the electrode on the flexible substrate side and sealing the through hole, the arrangement and sealing of the electrode leads are achieved. A configuration and a process for performing the stop are proposed (for example, JP-A-6-160420, JP-A-8-122359, and JP-A-10-90299). Thus, the inside of the sensor can be reduced in pressure or set to a desired atmosphere, and a semiconductor acceleration sensor that is easy to manufacture and has high reliability can be provided.

However, as the demand for high precision and high sensitivity for today's vibration type gyro sensors has further increased, in a configuration in which the conducting means is arranged through the through hole, the electric connection between the electrode leads on the drive side and the detection side has been increased. There has been a problem that the effects of dynamic crosstalk and detection noise cannot be ignored.

It is an object of the present invention to provide a vibration type gyro sensor having a configuration capable of reducing electric crosstalk between a drive side and a detection side electrode lead and detection noise in such a vibration type gyro sensor.

[0009]

Means for Solving the Problems The inventors of the present invention have provided various means for conducting between the drive-side and detection-side electrodes for the purpose of reducing electrical crosstalk between the drive-side and detection-side electrode leads and detection noise. As a result of the investigation, it has been found that the electrical crosstalk between the drive side and the detection side can be reduced by extracting the drive wiring and the detection electrode through the through holes formed in the glass surface of the different fixed substrate.

[0010] In addition, in the above-described configuration in which different continuity is established between the front and back surfaces of the bonding substrate constituting the sensor, the detection noise is reduced by mounting a separately manufactured amplifier on the side from which the detection electrode is taken out. In addition, the inventors have found that the sensor can be downsized, and have completed the present invention.

That is, according to the present invention, in a vibration type gyro sensor comprising a bonded substrate in which a fixed substrate and a flexible substrate are bonded, when driving and detecting continuity are respectively obtained from through holes provided in the fixed substrate, A vibrating gyrosensor characterized in that separate conducting means are provided from different main surfaces of a substrate.

Further, according to the present invention, there is provided a vibration-type gyro sensor having the above-mentioned configuration, wherein a detection current amplifier is mounted on a surface from which a detection electrode is taken out of the bonding substrate, and a bonding substrate provided with means for conducting to a driving electrode. On the main surface side, a configuration in which the conductive means and the wiring substrate are directly bonded via solder bumps is also proposed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The vibration type gyro sensor according to the present invention can be applied to any known configuration. A configuration proposed by the applicant, for example, a five-electrode type in which four arc-shaped electrodes are provided on the outer periphery of a central circular electrode (Japanese Patent Laid-Open No. 10-177)
034, JP-A-9-119944, JP-A-8-2618
50), a three-electrode type (JP-A-11-38038) composed of arc-shaped electrodes whose circumference is divided into three equal parts, or an acceleration sensor having various configurations such as a cantilever comb.

An example of the configuration of the vibration type gyro sensor according to the present invention will be described in detail with reference to the drawings. FIG. 1A is a vibration type gyro sensor having a configuration of a bonded substrate 5 in which glass substrates 3 and 4 are anodically bonded to both surfaces of a silicon substrate 2 on which a known ring vibrator 1 is formed. Depressed portions 3a, 3b, 4a,
4b, the vacuum cavities 6a and 6b are formed when the bonding substrate 5 is formed.

A conductive film of aluminum or the like is formed in the through-hole 7 for the detection electrode provided on the upper glass substrate 3 in accordance with the pattern of the detection electrode arranged on the outer peripheral side of the ring oscillator 1 of the silicon substrate 2. The detection electrode 10 is formed on the glass substrate 3.

Similarly, through holes 8 and 9 for driving electrodes provided on the lower glass substrate 4 in accordance with the patterns of the driving electrodes disposed on the center portion and the outer peripheral side of the ring oscillator 1 of the silicon substrate 2. A conductive film such as aluminum is formed, and drive electrodes 11 and 12 are further formed on the lower glass substrate 4.

Silicon substrate 2 on which ring oscillator 1 is formed
The detection electrode 10 is formed through a through-hole 7 for a detection electrode provided on the side of the upper glass substrate 3 joined to the upper glass substrate 3, and a through-hole 8 for a drive electrode provided on the lower glass substrate 4 opposite thereto, 9
The drive electrodes 11 and 12 are formed through the electrodes, and the conductive means for the detection and drive electrodes are separately arranged from both sides of the bonding substrate 5, so that the physical distance between the two conductive means is increased. Therefore, electrical crosstalk between the drive side and the detection side can be significantly reduced.

In the example shown in FIG. 1B, in the configuration of FIG. 1A described above, a detection current amplifier 20 separately manufactured is mounted on the surface of the upper glass substrate 3 on which the detection electrode 10 is arranged, and the detection electrode 10 and the wire 14 are used. Connected, and this configuration can reduce detection noise. Further, downsizing of the sensor can be realized.

In the example shown in FIG. 1C, the bonding substrate 5 having the structure shown in FIG. 1A is directly placed on, for example, the required wiring substrate 13 on which the sensor is mounted. The drive electrodes 11 and 12 are welded by interposing bumps made of gold, solder, or the like, so that each wiring 1
4, 15 can be implemented.

In the example shown in FIG. 1D, as shown in FIG. 1C, the bonding substrate 5 having the structure shown in FIG. 1A is connected to the wiring substrate 1 by interposing bumps between the driving electrodes 11 and 12 on the lower glass substrate 4 side.
After mounting on each of the wirings 14 and 15 of FIG. 3, an amplifier 20 for a detection current is mounted on the surface of the upper glass substrate 3 on which the detection electrode 10 is arranged.

The bonding substrate 5 for a vibrating gyro having the structure of the present invention is provided with conductive means for detecting and driving electrodes separately from both surfaces thereof, so that an electric cross between the driving side and the detecting side is provided. In addition to reducing the talk, it is possible to improve the mounting density on the electric circuit board by effectively utilizing both surfaces of the bonding substrate 5, and to reduce the size of the entire device.

In the present invention, any known means other than the above-described structure in which an electrode film is formed in the through-hole can be used as the means for conducting each electrode. In addition, the present invention can be applied to a vibrating gyroscope and a vibrator in which the inside of the cavity of the sensor is vacuum-sealed, as well as other structures that are not vacuum-sealed.

[0023]

2A and 2B show the upper glass substrate 3 in FIG.
The upper glass substrate 3 is provided with four through holes 7 for detection electrodes. FIG. 2C shows a silicon substrate 2 on which a ring oscillator 1 is formed, and wiring patterns 17 and 18 for a detection electrode and a drive electrode are alternately formed in four poles. FIG.
D and E show the lower glass substrate 4 in FIG. 1, and the lower glass substrate 4 is provided with five through holes 8 and 9 for drive electrodes.

The silicon substrate 2 is sandwiched between the upper glass substrate 3 and the lower glass substrate 4, and a predetermined anodic bonding is performed by applying a voltage of 400 ° C. and 800 V to form a single substrate. The detection electrode and the drive electrode were formed and arranged on both surfaces with an aluminum film.

When manufacturing a vibration type gyro sensor having the same configuration as that of FIG. 2, a detection electrode and a drive electrode were arranged on the upper glass substrate 3 side, and a sensor having a conventional wiring configuration was obtained.

The electrical crosstalk between the drive-side and detection-side electrode leads of the vibration type gyro sensor according to the present invention shown in FIG. 2 and the sensor having the above-described conventional wiring configuration was measured. The measurement results show that the sensor of the present invention
It was possible to reduce the electric crosstalk by 10 to 20% as compared with the conventional sensor.

[0027]

According to the present invention, since the extraction of the drive wiring and the extraction of the detection electrode are formed on the glass surfaces of different fixed substrates, the electric crosstalk between the drive side and the detection side can be reduced. Also, by mounting an amplifier for detection current separately manufactured on the extraction surface of the detection electrode,
Since the detection noise can be reduced and the other drive electrode side can be directly mounted on the wiring board via the bump, the size of the sensor can be reduced.

[Brief description of the drawings]

FIG. 1A is a cross-sectional explanatory view showing a configuration of a vibration type gyro sensor according to the present invention; FIG. 1B is a cross-sectional explanatory view showing a configuration in which a detection current amplifier is mounted on the configuration of FIG.
FIG. 4 is a cross-sectional explanatory view showing a configuration in which the vibration type gyro sensor having the configuration of FIG. A is mounted on a wiring board, and FIG. 4D is a cross-sectional explanatory view showing a configuration in which a detection current amplifier is mounted on the configuration of FIG.

2A and 2B are a top view and a side view showing an upper glass substrate, 2C is a top view showing a silicon substrate 2,
D and E are a top view and a side view showing a lower glass substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ring oscillator 2 Silicon substrate 3, 4 Glass substrate 3a, 3b, 4a, 4b Depression part 5 Joining substrate 6a, 6b Vacuum cavity 7, 8, 9 Through hole 10 Detection electrode 11, 12 Drive electrode 13 Wiring substrate 14, 15 Wiring 16 Bump 17 Detection electrode pattern 18 Drive electrode pattern 20 Amplifier

Claims (3)

[Claims] 1. A vibrating gyrosensor comprising a bonded substrate in which a fixed substrate and a flexible substrate are bonded to each other, wherein the vibrating gyrosensor has means for driving and detecting conduction from different main surfaces of the bonded substrate. 2. The vibration type gyrosensor according to claim 1, wherein an amplifier for a detection current is mounted on a surface from which the detection electrode is taken out of the bonding substrate. 3. The vibration according to claim 1, wherein the conductive means and the wiring substrate are directly bonded via bumps on the main surface side of the bonded substrate provided with the conductive means for driving electrodes. Type gyro sensor.