JP2008058144A - Inertial sensor and method of manufacturing inertial sensor - Google Patents

Abstract

An inertial sensor capable of accurately adjusting the angle of a detection axis of a detection element without deteriorating the detection performance of the detection element.
A crystal resonator element that detects a magnitude of a physical quantity in a predetermined detection axis direction, a support substrate that supports the crystal resonator element, and a ceramic package that houses the support substrate.
7 and a metal ball 2 connected between the support substrate 12 and the inner bottom surface of the ceramic package 17 and tilting the detection axis G of the crystal resonator element 11 by a predetermined angle from the normal direction to be detected.
[Selection] Figure 1

Description

The present invention relates to an inertial sensor such as an acceleration sensor and a gyro sensor, and a method for manufacturing the inertial sensor, and is particularly suitable for a vehicle-mounted navigation device and the like.

Car navigation devices are widely used. In such a car navigation apparatus, when detecting the current position of a vehicle such as an automobile, a so-called GPS (Global Positioning Sy
The method of positioning using a stem) and the method of autonomously measuring the moving direction and moving distance of the vehicle are used in combination. For this reason, in the car navigation device, the moving direction of the vehicle,
In addition, an inertial sensor such as a gyro sensor (angular velocity sensor) or an acceleration sensor for detecting an acceleration, an angular velocity, or the like applied to the vehicle in order to independently determine the moving distance is mounted.
When detecting an angular velocity, acceleration, or the like using such an inertial sensor, the detection axis needs to be directed in the direction to be detected. For example, in the case of a gyro sensor, the detection axis needs to be installed vertically upward. there were.

By the way, in recent years, the size of car navigation devices has been reduced, and a device main body (hereinafter referred to as “navigation main body”) that has been conventionally arranged under a seat or in a trunk room is interposed between a driver seat and a passenger seat. A type to be installed on the center console located has been developed.
FIG. 5 is a diagram showing a navigation main body installed on the center console.
) Is an overall perspective view, and (b) is a diagram showing a gyro sensor mounted on a car navigation body.

As shown in FIG. 5A, when the navigation main body 100 is installed on the center console 102, the display device is viewed from the viewpoint of the visibility of the display device 101 attached to the navigation main body 100 and the operability of an operation panel (not shown). 101 and the panel surface of the operation panel are preferably directed toward the driver's line of sight. That is, it is preferable that the navigation main body 100 is installed in the center console 102 while being inclined obliquely upward from the horizontal direction. However, the navigation console 100 is inclined obliquely upward and the center console 102
5 (b), the navigation main body from the vertical direction V, which is the direction in which the detection axis G of the gyro sensor 104 mounted on the printed circuit board 103 in the navigation main body 100 should be directed. Since the mounting angle (tilt angle) θ of 100 is inclined, an error occurs in the angular velocity detected by the gyro sensor 104.

In a normal car navigation apparatus, in order to correct a detection error of the gyro sensor 104 and the like generated by the mounting angle of the navigation main body 100, the detection result is corrected by software calculation processing. There is a limit to the processing. For example, when the inclination angle θ of the navigation main body 100 is 30 ° or more, the current state is that correction cannot be performed by software calculation processing.
For this reason, in the car navigation device, an inertial sensor that can accurately detect even when mounted obliquely is required, and various types of such sensors have been proposed.
For example, Patent Document 1 discloses an angular velocity sensor in which the detection axis is inclined without changing the sensor shape or the sensor mounting method by inclining an angular velocity detection element inside the sensor with a holding member.

Further, in Patent Document 2, in a sensor device including a detection element that detects the direction and size of a physical quantity having a certain directionality, and a mounting portion that fixedly supports the detection element, the detection element is in the direction and size. Inclined by a preset reduction angle in a decreasing direction that reduces the angle difference predicted as the difference between the direction of the detection axis that is the reference for detecting the detection and the direction of the physical quantity that is actually applied to the detection element during the detection Thus, a sensor device is disclosed that is fixed to the mounting portion.
In Patent Document 3, the angle of the vibrator in the package is set by a leg portion for connecting the vibrator to the support substrate and an adhesive for connecting the support board and the package substrate, and the detection axis of the vibrator is set. A support structure for a vibrator is disclosed that is oriented in a desired direction.
WO03 / 100350 JP 2003-227844 A JP 2005-249428 A

However, in Patent Document 1, the holding member that holds the vibrator on the base can be elastically deformed, and the elastic deformation member is elastically deformed to adjust the angle of the detection axis of the vibrator. Therefore, there is a drawback that the adjustment accuracy of the detection axis is poor.
Further, Patent Document 2 has a drawback that the detection axis adjustment accuracy is poor because the detection element is fixed to the mounting portion with an adhesive to adjust the angle of the detection axis of the vibrator.
Furthermore, in Patent Document 3, since the detection axis of the vibrator is set by curing the uncured adhesive after changing the amount of the uncured adhesive, the accuracy of angle adjustment of the detection axis is similar to the above. There was a fault that it was bad.

Furthermore, in the sensors disclosed in Patent Documents 1 and 2, since the angle itself for attaching the detection element to the attachment part is adjusted, the attachment part causes vibration leakage from the detection element and unnecessary vibration modes. There was also a risk of deteriorating detection performance.
The present invention has been made in view of the above points, and provides an inertial sensor capable of accurately adjusting the angle of the detection axis of the detection element without deteriorating the detection performance of the detection element, and a method for manufacturing the same. The purpose is to do.

In order to achieve the above object, an inertial sensor of the present invention includes a detection element that detects the magnitude of a physical quantity in a predetermined detection axis direction, a support substrate that supports the detection element, a package substrate that houses the support substrate, An inclination member that is connected between the support substrate and the inner bottom surface of the package substrate and inclines the detection axis of the detection element supported by the support substrate by a predetermined angle from the normal direction to be detected is provided.
As described above, in the present invention, the detection axis can be tilted by a predetermined angle from the detection direction to be detected without tilting and fixing the detection element itself. Generation | occurrence | production can be suppressed and it can prevent that the detection performance of a detection element deteriorates.
In addition, since the inclined member is arranged between the support substrate and the inner bottom surface of the package substrate so that the detection axis of the detection element is inclined by a predetermined angle, the accuracy of the inclination angle of the detection axis can be improved.

In addition, in the inertial sensor of the present invention, a metal ball is used for the inclined member.
Since the metal sphere has high processing accuracy, if the metal sphere is arranged between the support substrate and the inner bottom surface of the package substrate and the detection axis of the detection element is inclined by a predetermined angle, the accuracy of the inclination angle of the detection axis is improved. Can be increased.
In addition, when a metal sphere is used for the inclined member, variations in the inclination angle of the detection axis depending on the diameter can be suppressed. In addition, when a metal sphere is used for the inclined member, the metal sphere can be connected to the position of the center of gravity of the internal pad by the self-alignment action, so that variations in the inclination angle of the detection axis depending on the connection position of the metal sphere can be suppressed. Furthermore, since the metal sphere has conductivity, it can be used as a member for conducting between the support substrate and the package substrate.
Further, in the inertial sensor of the present invention, if the detection axis is inclined at a predetermined angle from the detection direction to be detected using two kinds of metal balls having different diameters as the inclined members, the angle of the detection axis can be easily adjusted. Can do.

The inertial sensor manufacturing method of the present invention is the inertial sensor manufacturing method of the present invention, wherein a step of mounting a semiconductor integrated circuit on an inner bottom surface of a package substrate and an inclined member on an internal pad formed on the package substrate , A step of mounting the support substrate on the internal pad including the inclined member, and a step of vacuum-sealing the space including the support substrate of the package substrate.
In this way, the inertial sensor of the present invention can be manufactured. In addition, since it is not necessary to perform slit processing or the like on the detection element as in the prior art, the processing cost of the detection element can be reduced, and thus the cost can be reduced.

Hereinafter, embodiments of the present invention will be described in detail.
In the present embodiment, a gyro sensor will be described as an example of the inertial sensor of the present invention.
FIG. 1 is a diagram showing a configuration of a gyro sensor according to a first embodiment of the present invention.
) Is an overall perspective view, and (b) is a diagram schematically showing the internal structure. In addition, illustration of the cover body 16 is abbreviate | omitted in (a).
A gyro sensor 10 shown in FIGS. 1A and 1B includes a crystal vibrating element 11 as a detecting element.
Have The crystal resonator element 11 is mechanically and electrically connected to the support substrate 12 by the legs 13.

A semiconductor integrated circuit (hereinafter referred to as “IC circuit”) 15 including an oscillation circuit is connected to an inner bottom surface of a ceramic package 17 made of an insulating member such as ceramic.
A step portion is formed on the inner bottom surface of the ceramic package 17, and an internal pad 14 for fixing the support substrate 12 is formed on the upper surface of the step portion.
In the gyro sensor 10 of the present embodiment, when the support substrate 12 is fixed to the internal pad 14, the metal ball 2 that is an inclined member is formed on the internal pad 14 formed on one side of the ceramic package 17. Are connected by solder 3. As a result, the detection direction (vertical direction) in which the detection axis G of the crystal resonator element 11 as the detection element should be detected originally.
The angle is inclined from V by a predetermined angle θ.

Here, the metal ball 2 that is an inclined member is, for example, a solder ball having a core member made of Cu, resin, glass, or the like, and having a surface coated with solder.
A lid 16 made of metal is bonded to the upper surface of the ceramic package 17 by a sealing member 19 such as a low melting point metal. Thereby, the inside of the ceramic package 17 is vacuum-sealed. It is also possible to use a glass lid as the lid body 16,
In this case, low-melting glass or the like is used as the sealing member 19.
A mounting electrode 18 is formed from the outer bottom surface to the side surface of the ceramic package 17. The mounting electrode 18 is connected to the IC circuit 15 via an internal conductor (not shown) formed in the ceramic package 17.

The excitation electrode (not shown here) of the crystal resonator element 11 and the IC circuit 15 are connected via a package internal wiring. For example, an excitation electrode 36 (described later) of the crystal unit 11 is connected to the support substrate 12 from the back surface of the base 31 by wire bonding or leads that support the crystal unit 11. The support substrate 12 is electrically connected to the IC circuit through face-down or wire bonding via the package internal wiring. In this embodiment, since the metal sphere 2 is used as the inclined member, the internal pad 14 of the ceramic package 17 is connected to the IC circuit 15 by internal wiring, and the support substrate 12 connected to the internal pad 14 is connected. If the portion (not shown) and the excitation electrode of the crystal resonator element 11 are connected,
It is also possible to connect the crystal resonator element 11 and the IC circuit 15 via the metal sphere 2.

FIG. 4A is a plan view schematically showing a crystal resonator element 11 according to one embodiment of the present invention. FIG. 4B is a plan view showing the vibration in the detection vibration mode of the crystal resonator element 11. The crystal resonator element 11 of this example includes a base 31 and a pair of detection vibrating pieces 32a and 3 protruding from the base 31.
2b, a pair of connecting portions 33 protruding from the base portion 31, and driving vibration pieces 34a, 34b, 34c, 34d provided at the tips of the connecting portions 33. Each drive vibrating piece 34a, 3
Each main surface of 4b, 34c, 34d is formed with an elongated groove, and the cross-sectional shape of each drive vibration piece 34a, 34b, 34c, 34d is substantially H-shaped. An excitation electrode (drive electrode, hereinafter the same) 36 is formed in the groove. Each drive vibrating piece 34a, 34b,
Wide ends or weight portions 38a, 38b, 38c, 38 are provided at the respective tips of 34c, 34d.
d is provided. Each main surface of each detection vibrating piece 32a, 32b is formed with an elongated groove, and the cross-sectional shape of each detection vibration piece 32a, 32b is substantially H-shaped. A detection electrode 37 is formed in the groove. A wide part or a weight part 35a, 35b is provided at the tip of each detection vibrating piece 32a, 32b.

FIG. 4A shows drive mode vibration. At the time of driving, each driving vibration piece 34a, 34b, 3
4c and 34d each vibrate and vibrate as indicated by an arrow A with the base 39 to the connection portion 33 as the center. In this state, the crystal resonator element 11 is rotated at an angular velocity ω around a rotation axis G substantially perpendicular to the crystal resonator element 11. Then, as shown in FIG. 4B, the weight portions 38a, 38b, 3
Coriolis force F is applied to 8c and 38d in a direction perpendicular to both the bending vibration direction A and the rotation axis G. As a result, the connecting portion 33 bends and vibrates as indicated by an arrow B around the base 33a to the base portion 31. Each of the detection vibrating pieces 32a and 32b is flexibly vibrated as indicated by an arrow C around the base 40 of the base 31 by the reaction. A piezoelectric phenomenon is generated by the bending vibration of the arrow C, and the potential of the detection electrode 37 changes. The change in potential is detected by a detection circuit in the IC circuit 15 to obtain the angular velocity ω around the rotation axis G. Here, when the crystal axis direction of the + X axis / −X axis of the crystal resonator element 11 is set to the direction of the arrow A and the crystal axis direction of the Z axis of the crystal resonator element 11 is aligned with the rotation axis G, the detection efficiency is high. .

Here, in the gyro sensor 10 of the present embodiment, the metal ball 2 is interposed between the internal pad 14 formed on one side of the ceramic package 17 and the support substrate 12, thereby detecting the detection axis of the crystal resonator element 11. G is inclined by a predetermined angle θ from the original detection direction (vertical direction) V to be detected. In this manner, the detection axis G can be tilted by a predetermined angle from the direction to be detected without tilting and fixing the crystal vibration element 11 itself that is the detection element. It is possible to suppress the occurrence of vibration leakage, unnecessary vibration mode, and the like, and to prevent the detection performance of the detection element from deteriorating.
The inclination angle θ of the gyro sensor 10 is determined by the length L from the substrate edge serving as a fulcrum when the support substrate 12 is inclined to the contact point of the metal sphere 2 and the diameter φ of the metal sphere 2. Since the metal sphere 2 configured as described above has extremely high processing accuracy, use of the metal sphere 2 as an inclined member suppresses variation in the inclination angle of the detection axis G caused by variation in the diameter φ of the metal sphere 2. Can do.

Further, since the metal sphere 2 has conductivity, the metal sphere 2 can be used as a member that conducts between the support substrate 12 and the ceramic package 17. Therefore, the internal pad 14 of the ceramic package 17 is connected to the IC circuit 15 by the internal wiring, and the internal pad 1
If the portion of the support substrate 12 (not shown) connected to 4 and the excitation electrode of the crystal resonator element 11 are connected, the crystal resonator element 11 and the IC circuit 15 are electrically connected via the metal ball 2. be able to.

Further, when the metal sphere 2 is used as the inclined member, the metal sphere 2 is attached to the internal pad 1 by the surface tension when the silver paste (solder) 3 for connecting the metal sphere 2 to the internal pad 14 is melted.
4 can be arranged at the center of gravity position. That is, when the metal sphere 2 is used as the inclined member, the metal sphere 2 can be disposed at the center of gravity of the internal pad 14 by the self-alignment action of the metal sphere 2. As a result, it is possible to improve the accuracy of the length L from the edge of the support substrate 12 to the contact point of the metal sphere 2, so that the metal sphere 2 extends from the edge of the support substrate 12 serving as a fulcrum.
It is possible to suppress the variation in the inclination angle of the detection axis G caused by the variation in the length L up to the above.
Further, when the metal ball 2 is used as the inclined member, the metal ball 2 is attached to the internal pad 1 by the solder 3.
The shape of the solder fillet when connected to 4 becomes stable, and there is an advantage that the connection strength can be increased.
In the present embodiment, the case where the shape of the internal pad 14 is rectangular has been described as an example. However, this is merely an example, and the shape of the internal pad 14 may be circular.

FIG. 2 is a diagram schematically showing the configuration of the gyro sensor according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same site | part as FIG. 1, and detailed description is abbreviate | omitted.
In the gyro sensor 20 shown in FIG. 2, when the support substrate 12 is connected to the internal pad 14 in the ceramic package 17, the metal ball 2 a is connected to the internal pad 14 on one side, and the internal on the other side. By connecting a metal sphere 2b having a diameter smaller than that of the metal sphere 2a to the pad 14, the detection axis G is originally detected from the detection direction (vertical direction V) due to the difference in diameter between the metal sphere 2a and the metal sphere 2b. The angle is inclined by θ.
Even in such a configuration, as in the first embodiment, it is not necessary to incline the crystal resonator element 11 itself and fix it to the mounting portion. It is possible to prevent the occurrence of a mode or the like.
Also in this case, since the processing accuracy of the metal balls 2a and 2b used as the inclined members is extremely high, it is possible to suppress the variation in the inclination angle of the detection axis G caused by the variation in the diameter of the metal balls 2a and 2b.

Further, since the metal balls 2a and 2b have conductivity, the metal balls 2a and 2b are connected to the inner pad 1
4, the internal pad 14 and the support substrate 12 can be connected via the metal ball 2a or 2b. Further, since the metal balls 2a and 2b can be arranged at the center of gravity of the internal pad 14 by the self-alignment action of the metal balls described above, the variation in the length L from the metal ball 2a to the metal ball 2b as a fulcrum is varied. The variation in the inclination angle of the detection axis G caused by the above can be suppressed. Also in this case, the metal balls 2 a and 2 b can be used as a member for conducting between the support substrate 12 and the ceramic package 17.
In the present embodiment, the case where the shape of the internal pad 14 is rectangular has been described as an example. However, this is merely an example, and the shape of the internal pad 14 may be circular.

Next, a method for manufacturing the gyro sensor of the present embodiment as described above will be described.
FIG. 3 is a diagram showing an example of a manufacturing procedure of the gyro sensor of the present embodiment.
To manufacture the gyro sensor of this embodiment, first, as an IC circuit mounting step S1, a ceramic package 1 in which internal pads 14, mounting electrodes 18, internal conductors (not shown), and the like are formed.
The IC circuit 15 is mounted on the inner bottom surface of 7 by face-down bonding, for example.
Next, as a metal ball mounting step S2, a silver paste is applied to the internal pad 14 on which the metal ball 2 is placed, and then the metal ball 2 is placed on the internal pad 14 to perform reflow.
Is implemented.

Next, a silver paste is applied on both sides of the internal pad 14 as a support substrate mounting step S3.
At this time, when the metal sphere 2 is connected on the internal pad 14, a silver paste may be applied on the metal sphere 2. After that, the support substrate 12 on which the crystal resonator element 11 as the detection element is mounted is placed on the internal pad and reflowed, whereby the internal pad 1 is sandwiched between the metal balls 2.
The support substrate 12 is mounted on the four doors.
Thereafter, as a vacuum sealing step (S4), the inside of the ceramic package 17 is sealed in a vacuum state. Thereby, the gyro sensor 10 (20) of this embodiment shown in FIG. 1, FIG. 2 is producible. In addition, since it is not necessary to perform slit processing or the like on the crystal resonator element 11 that is a detection element as in the prior art, the processing cost of the crystal resonator element 11 can be reduced.

In the present embodiment, the gyro sensor has been described as an example of the inertial sensor of the present invention.However, the gyro sensor is merely an example, and any sensor that detects the magnitude of the physical quantity in the detection axis direction by the detection element may be used. For example, it can be applied to an acceleration sensor.
In this embodiment, since the gyro sensor is used as an example of the inertial sensor, the normal direction to be detected is the vertical direction V. However, when the inertial sensor is an acceleration sensor, the normal direction to be detected is advancing. Needless to say, the direction is the horizontal direction.
Further, in the present embodiment described so far, the detection axis G of the gyro sensor using an inclined member.
Has been described by taking as an example a case where the angle of inclination is inclined by a predetermined angle in a specific direction (in the present embodiment, the right side of the drawing). For example, by changing the position of the internal pad 14 where the metal ball 2 is connected, the inclination of the detection axis G It is also possible to adjust the inclination direction in addition to the angle.

(A) (b) is the figure which showed the structure of the gyro sensor which concerns on the 1st Embodiment of this invention. It is the figure which showed the structure of the gyro sensor which concerns on the 2nd Embodiment of this invention. It is the figure which showed an example of the manufacturing procedure of the gyro sensor of this embodiment. (A) (b) is the figure which showed the structure of the quartz-crystal vibrating element of this invention. (A) is the figure which showed the car navigation main body installed in the center console, (b) is the figure which showed the gyro sensor mounted in the car navigation main body.

Explanation of symbols

10, 20 ... Gyro sensor, 2, 2a, 2b ... Metal balls, 3 ... Silver paste (solder), 1
DESCRIPTION OF SYMBOLS 1 ... Crystal oscillation element, 12 ... Support substrate, 13 ... Leg part, 14 ... Internal pad, 15 ... Semiconductor integrated circuit, 16 ... Cover body, 17 ... Ceramic package, 18 ... Mounting electrode, 19 ... Sealing member

Claims (4)

A detection element for detecting the magnitude of a physical quantity in a predetermined detection axis direction;
A support substrate for supporting the detection element;
A package substrate for storing the support substrate;
An inclined member that is arranged between the support substrate and the inner bottom surface of the package substrate and inclines a detection axis of the detection element supported by the support substrate by a predetermined angle from a normal direction to be detected;
An inertial sensor comprising:   The inertial sensor according to claim 1, wherein the inclined member is a metal sphere. 2. The inertial sensor according to claim 1, wherein two types of metal spheres having different diameters are used as the inclined member, and the detection axis is inclined at a predetermined angle from the normal direction. A method for manufacturing an inertial sensor according to any one of claims 1 to 3,
Mounting a semiconductor integrated circuit on the inner bottom surface of the package substrate;
Mounting the inclined member on an internal pad formed on the package substrate;
Mounting the support substrate on the internal pad including the inclined member;
Vacuum-sealing a space including the support substrate of the package substrate;
The manufacturing method of the inertial sensor characterized by including.

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