JP2010164499A - Physical quantity detector - Google Patents

Abstract

Provided is a physical quantity detection device in which there is little process variation of the forming amount due to inner leads and temperature drift of a stationary output voltage is small.
A gyro sensor having a structure in which a crystal vibrating piece 12 is pushed up to a lid 50 side by an inner lead 36 to elastically support the crystal vibrating piece 12 in a cavity 68 of a package 40, and the crystal vibrating piece 12 in the lid 50 is provided. A spacer 52 is provided on the surface opposite to the surface, and the spacer 52 is in contact with the crystal vibrating piece 12 in a state where the package 40 is sealed with the lid 50, and regulates the push-up amount of the crystal vibrating piece 12 by the inner lead 36. And In the gyro sensor 10 having such a feature, the spacer 52 is desirably provided at a position in contact with the center of the crystal vibrating piece 12 by the inner lead 36.
[Selection] Figure 1

Description

The present invention relates to a physical quantity detection device, and more particularly to a physical quantity detection device with improved impact resistance and mounting height accuracy.

Gyro sensors and acceleration sensors are known as physical quantity detection devices that detect physical quantities such as angular velocity and acceleration. And as a physical quantity detection element in such a physical quantity detection device, it has a base, a pair of detection arms extended from the base, a pair of support arms, and a drive arm that forms a pair extended from each support arm There is a so-called WT type. In response to the recent demand for downsizing and thinning, the physical quantity detection element has caused the following problems due to the reduction in the size of the base fixed to the substrate or the like. That is, it becomes difficult to keep the application amount of the adhesive and the area of the bonding surface uniform by reducing the area of the bonding portion. As described above, when the shape of the adhesive layer to which the physical quantity detection element is bonded and the amount of the adhesive are non-uniform, or when the adhesive is dripped or unnecessarily wraps around, the overall physical properties of the adhesive layer vary. When such a change in physical properties occurs, there is a problem that the vibration characteristics of the element change and the physical quantity detection accuracy decreases.

As means for suppressing such a change in vibration characteristics, Patent Document 1 discloses an inner lead (
A configuration in which a physical quantity detection element is mounted using a bonding wire is disclosed. Specifically, the tip end side of the inner lead, that is, the joint portion side with the physical quantity detection element is bent so that the physical quantity detection element is mounted in a state of floating from a substrate such as a bottom plate of the package.

JP 2003-294450 A

According to the mounting form disclosed in Patent Document 1, the physical quantity detection element does not directly contact the bottom surface of the package or the like, and it is possible to avoid excessive wraparound of the adhesive. In addition, since the joint portion for achieving electrical conduction is substantially point contact, an error in the area of the joint surface can be reduced. For this reason, it is possible to suppress changes in the vibration characteristics of the element due to the reasons described above, and the impact resistance as a physical quantity detection device is improved because the inner lead serves as a spring.

However, in the mounting method using the inner lead as described above, the resonance frequency of the inner lead changes depending on the height (forming amount) for supporting the element. A change in the resonance frequency of the inner lead causes a temperature drift of the stationary output voltage, which is a problem related to improvement in detection accuracy.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a physical quantity detection device that solves the above-described problems and has less variation in the forming amount due to the inner lead and less temperature drift of a so-called null voltage (static output voltage).

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
Application Example 1 A physical quantity detection device having a structure in which a physical quantity detection element is pushed up to a lid side by an inner lead and elastically supports the physical quantity detection element in a cavity of a package, and is opposed to the physical quantity detection element in the lid. A spacer is provided on a surface, and the spacer is in contact with the physical quantity detection element in a state where the package is sealed with the lid, and regulates a push-up amount of the physical quantity detection element by the inner lead. apparatus.

According to the physical quantity detection device having such a feature, it is possible to configure a physical quantity detection device with little variation in the forming amount of the physical quantity detection element. For this reason, the temperature drift of the stationary output voltage is small, and a physical quantity detection device with high detection accuracy and reliability can be obtained.

Application Example 2 The physical quantity detection device according to Application Example 1, wherein the spacer is provided at a position in contact with the center between the physical quantity detection element support points by the inner leads. .

According to the physical quantity detection device having such a feature, since the spacer contacts the center between the physical quantity detection element support points, the forming amount can be adjusted stably even when only one spacer is used. it can. Further, by adopting a configuration in which only one center between the physical quantity detection element support points is supported with a single spacer, the deformation generated in the physical quantity detection element is not affected when a physical quantity such as angular velocity or acceleration is added. For this reason, there is no possibility that the detection sensitivity of physical quantity falls.

Application Example 3 The physical quantity detection device according to Application Example 1, wherein at least three spacers are provided and are in contact with the physical quantity detection element at at least three points.

According to the physical quantity detection device having such a feature, the surface can be configured by connecting the contact points of the spacer and the physical quantity detection element with a line. For this reason, the inclination of the mounting state can be corrected together with the adjustment of the forming amount of the physical quantity detection element.

Application Example 4 The physical quantity detection device according to Application Example 1, wherein the spacer has a structure in surface contact with the physical quantity detection element.
According to the physical quantity detection device having such a feature, the inclination of the mounting state can be corrected along with the adjustment of the forming amount of the physical quantity detection element. Further, even when the mounting position of the physical quantity detection element is shifted from the center of the package, the forming amount can be adjusted stably.

Application Example 5 The physical quantity detection device according to any one of Application Examples 2 to 4, wherein the physical quantity detection element includes a base, a pair of support arms extending from the base, and a pair of detection arms. And a pair of drive arms extending from each of the support arms, and the spacer is also provided at a position in contact with the intersection of the support arm and the drive arm. Physical quantity detection device.

By having such a feature, it is possible to suppress deformation of the support arm when an impact is applied in the thickness direction of the physical quantity detection element. For this reason, it becomes possible to prevent the lid and the drive arm from contacting due to deformation.

It is a figure which shows the structure of the gyro sensor which concerns on 1st Embodiment. It is a top view which shows the form of the crystal vibrating piece which concerns on embodiment. It is a top view which shows the structure of the support substrate which concerns on embodiment. It is a figure which shows the structure of the gyro sensor which concerns on 2nd Embodiment. It is a figure which shows the structure of the gyro sensor which concerns on 3rd Embodiment. It is a figure which shows the structure of the gyro sensor which concerns on 4th Embodiment.

DESCRIPTION OF EMBODIMENTS Embodiments according to a physical quantity detection device of the present invention will be described in detail below with reference to the drawings. In the following embodiments, a gyro sensor will be described as an example of the physical quantity detection device.
First, the gyro sensor according to the first embodiment will be described in detail with reference to FIG.

The gyro sensor 10 according to the present embodiment is configured based on a crystal vibrating piece 12 as a physical quantity detection element, a support substrate 30, an IC 38, a package 40, and a lid 50.
FIG. 1 is a side sectional view of the gyro sensor. The crystal vibrating piece 12 plays a role of detecting an angular velocity. In the present embodiment, the quartz crystal resonator element 12 is taken as an example of the physical quantity detection element. However, the material of the resonator element is not particularly limited as long as it is a member having a piezoelectric effect, such as lithium niobate or lithium tantalate. . A specific configuration of the crystal vibrating piece 12 will be described below with reference to FIG.

The quartz crystal resonator element 12 according to the present embodiment includes a base portion 14, a pair of detection arms 16 a and 16 b extending from the base portion 14, and a pair of extensions extending from the base portion 14 in a direction orthogonal to the detection arms 16 a and 16 b. The support arm 20 includes two pairs of drive arms 22a to 22d extending in parallel to the detection arms 16a and 16b from the tip of each support arm 20. Crystal resonator element 1 shown in FIG.
2, weights 18a, 18b, and 24a to 24d that play a weighting role are provided at the tips of the detection arms 16a and 16b and the drive arms 22a to 22d. Further, detection electrodes (not shown) and drive electrodes (not shown) as excitation electrodes are formed on the detection arms 16a and 16b and the drive arms 22a to 22d, respectively, and are connected to an input / output electrode 26 formed on the base portion 14. Has been. In addition, regarding the cross-sectional shapes of the detection arms 16a and 16b and the drive arms 22a to 22d, by providing a groove (not shown) in the arm and adopting a so-called H-shaped cross section, a direction orthogonal to the depth direction of the groove The bendability may be improved to increase the detection sensitivity.

The support substrate 30 is a bottom surface 42 of the package 40, which will be described in detail later, or step portions 44 and 46.
It plays a role of supporting the crystal vibrating piece 12 in a floating state. As its structure, it is comprised from the conductive wire (inner lead) 36 (36a-36f) which has flexibility, and the insulating resin film 32 which coat | covers the said inner lead 36. FIG. An opening 34 is provided in the resin film 32 near the center of the support substrate 30, and the inner leads 36 are exposed. The inner lead 36 located in the opening 34 is bent so as to be offset to the side where the crystal vibrating piece 12 is disposed with respect to the main surface of the support substrate 30 in order to support the crystal vibrating piece 12 in a floating state. Yes. Here, the tip (one end) of the offset inner lead 36
Becomes a connection terminal connected to the input / output electrode 26 of the crystal vibrating piece 12. Further, the other end of each inner lead 36 serves as a connection terminal connected to an internal connection terminal (not shown) disposed in a stepped portion 46 of the package 40 which will be described in detail later.

The IC 38 controls the drive arms 22a to 22d of the crystal vibrating piece 12 described above,
It is an integrated circuit that plays a role of detecting signals obtained by the detection arms 16a and 16b of the crystal vibrating piece 12. The IC 38 is mounted on the bottom surface 42 of the package via an adhesive 60 or the like. A connection pad (not shown) formed on the active surface and an internal connection terminal (not shown) arranged on the step portion 44 of the package 40 are electrically connected via a metal wire 45.

The package 40 is a box that accommodates the crystal resonator element 12, the support substrate 30, and the IC 38 described above. On the inner side of the package 40, a stepped cavity 68 composed of stepped portions 44 and 46 and a bottom surface 42 is formed. Note that the constituent member may be an insulating ceramic or the like.

The bottom surface 42 of the package 40 and the step portions 44 and 46 are provided on the support substrate 30 and the IC 3 described above.
An internal connection terminal (not shown) for mounting 8 is provided. An external connection terminal (not shown) is provided on the external bottom surface (back surface) of the package 40. The internal connection terminal and the external connection terminal described above are electrically connected through a through hole (not shown).

The lid 50 is a lid that seals the opening of the package 40 described above. Generally, a metal (alloy: for example, Kovar) or glass (for example, soda glass) whose linear expansion coefficient approximates that of the package 40 is used as a constituent member. For the connection between the package 40 and the lid 50, as the connecting member 66, a low melting point metal such as Kovar is used when the lid 50 is made of metal, and a low melting point glass is used when the lid 50 is made of glass.

The lid 50 according to the present embodiment includes a spacer 52 on the surface facing the crystal vibrating piece 12. The spacer 52 is formed when the package 40 is sealed with the lid 50.
2, contacts the base portion 14, presses down the crystal vibrating piece 12 pushed up by the inner lead 36, and adjusts the forming amount of the crystal vibrating piece 12. Even during mass production, the thickness of the substrate constituting the package 40 is substantially uniform. For this reason, the forming amount of the crystal vibrating piece 12 can be adjusted substantially evenly by being pushed down by the thickness of the spacer 52 from the lid 50 placed on the upper portion of the opening of the package 40.

The spacer 52 may be formed in a convex shape by cutting a thick flat plate, or may be formed by placing a convex portion on a flat lid. When cutting a thick flat plate, etching may be used. Spacer 52 thickness (height) depending on lid material and etching time
This is because it can be kept substantially uniform and accurate.

In the case where the convex portions are to be stacked, after applying resin or metal to the lid, the height is adjusted by pressing with a surface plate parallel to the lid main surface. Even in such a case, the height of the spacer 52 can be controlled by the substance to be applied, the application amount, and the pressing force. In addition, the example shown in FIG. 1 is an example at the time of forming the convex part used as the spacer 52 by an etching. The formation of the spacer 52 by etching enables batch processing, so that it is excellent in mass productivity and can reduce the unit unit price at a low cost.

The spacer 52 is provided at a position in contact with the center of the crystal vibrating piece 12, in other words, the center of the input / output electrode 26 that is a joint portion with the inner lead 36 (the surface to be contacted is opposite to the surface where the input / output electrode 26 is formed) To. One that touches the center of the quartz crystal vibrating piece 12 and has a very small contact surface area (
For example, the point contact) does not affect the deformation of the crystal unit 12 when the angular velocity is applied. For this reason, there is no decrease in sensitivity as the gyro sensor 10.

The gyro sensor device 10 having the components as described above is provided on the bottom surface 4 of the package 40.
The adhesive 60 is applied to 2 and the IC 38 is mounted. After mounting the IC 38, the metal wire 45
Wire bonding is performed through the wire to achieve electrical connection with the internal mounting terminals of the package 40.

Next, the inner lead 36 of the support substrate 30 is bonded to the crystal vibrating piece 12 via the bumps 64. After the crystal resonator element 12 is bonded, the conductive adhesive 62 is applied to the internal mounting terminals provided in the stepped portion 46 of the package 40, and the support substrate 30 is mounted. With this configuration, the quartz crystal vibrating piece 12 is elastically supported by the inner lead 36.

The crystal resonator element 12 may be mounted on the inner lead 36 of the support substrate 30 by spot welding, conductive adhesive, soldering, or the like, in addition to ultrasonic bonding via the bumps 64. Similarly, the mounting of the support substrate on the stepped portion of the package may be bonding via bumps or the like.

After mounting the support substrate 30, the lid 50 is bonded to the opening of the package 40. The spacer 52 formed on one surface of the lid 50 is bonded to the crystal vibrating piece 12 by the bonding of the lid 50.
The base 14 is pressed, and the forming amount of the crystal vibrating piece 12 is adjusted. The pressing position of the base portion 14 by the spacer 52 is a support point (input / output electrode 26) by the inner lead 36.
It is desirable to be the center between. In this way, by setting the contact point between the crystal vibrating piece 12 and the spacer 52 as one point, there is no influence on the deformation of the crystal vibrating piece 12 when an angular velocity is applied to the gyro sensor 10. For this reason, there is no possibility that the detection sensitivity of angular velocity will fall.

The lid 50 may be joined by seam welding using a seam ring or welding using a low melting point glass. The lid 50 is joined in a vacuum atmosphere, and the internal space of the package 40 is evacuated. This is so as not to disturb the excitation of the crystal unit 12.

According to the gyro sensor 10 having such a configuration, the process variation of the forming amount of the crystal vibrating piece 12 is eliminated. For this reason, there is no variation in the resonance frequency of the inner lead 36, and the symmetry of the joined state of the inner lead 36 is ensured. Thereby, the temperature drift of the stationary output voltage of the gyro sensor 10 is suppressed, and the detection accuracy and reliability of the angular velocity can be improved.
Further, since the spring action by the inner lead 36 is effective on the crystal vibrating piece 12, the mounting height of the crystal vibrating piece 12 can be determined with high accuracy while ensuring impact resistance.

Next, a gyro sensor according to a second embodiment will be described with reference to FIG. The basic configuration of the gyro sensor 10a of this embodiment is the same as that of the gyro sensor 10 according to the first embodiment described above. The difference is in the number and arrangement position of the spacers provided on one surface of the lid. Therefore, portions that are the same as the function thereof will be denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted. In FIG. 4, FIG.
FIG. 4A is a diagram showing a side cross section of the gyro sensor, and FIG. 4B is a plan view showing a configuration of a crystal vibrating piece.

The spacer 52 in the first embodiment is 1 at a position in contact with the center of the crystal vibrating piece 12.
One configuration was provided. In contrast, in the gyro sensor 10a according to the present embodiment,
At least three spacers 52a to 52c are provided so as to be in contact with at least three points of the base portion 14 in the quartz crystal vibrating piece 12. Three spacers 52a
The arrangement of .about.52c is not linear, and the line connecting the three spacers 52a to 52c is preferably in a positional relationship that forms a triangle.

With such a configuration, the three points connecting the spacers 52a to 52c form a surface, and the tilt at the time of mounting the crystal vibrating piece 12 can be corrected. In addition, about another structure, an effect | action, and an effect, the gyro sensor 10 which concerns on 1st Embodiment mentioned above.
It is the same.

Next, a gyro sensor according to a third embodiment will be described with reference to FIG. The basic configuration of the gyro sensor 10b of the present embodiment is the first and second described above.
This is the same as the gyro sensor 10, 10a according to the embodiment. The difference is in the form of a spacer provided on one side of the lid. Therefore, portions that are the same as the function thereof will be denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted. 5A is a diagram showing a side cross section of the gyro sensor, and FIG. 5B is a plan view showing the configuration of the crystal vibrating piece.

The spacer 52d of the gyro sensor 10b according to the present embodiment has a surface similar to the base portion 14 of the crystal vibrating piece 12 and is configured to contact the base portion 14 on the surface.

By adopting such a configuration, even if the mounting position of the crystal vibrating piece 12 deviates from the center position of the package 40 due to process variations, the forming amount of the crystal vibrating piece 12 can be stably adjusted. it can. Further, the spacer 52d and the base portion 14 of the quartz crystal vibrating piece 12 are used.
Are in contact with each other on the surface, it is possible to prevent the quartz crystal vibrating piece 12 from rotating so as to oscillate the detection shaft due to vibration or impact (rotation around the X axis or the Y axis). For this reason, it is possible to prevent the drive arm 22, the detection arm 16, or the support arm 20 from coming into contact with the lid 50. In addition, about another structure, an effect | action, and an effect, it is the same as that of the gyro sensor 10a which concerns on 2nd Embodiment mentioned above.

Next, a gyro sensor according to a fourth embodiment will be described with reference to FIG. The gyro sensor 10c according to the present embodiment has one or more spacers that contact the base of the crystal vibrating piece or a spacer that contacts the base at the surface. That is, the basic configuration is any one of the gyro sensor 10 according to the first embodiment to the gyro sensor 10b according to the third embodiment described above. Therefore, portions that are the same as the function thereof will be denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted. 6A is a diagram showing a side cross section of the gyro sensor, and FIG. 6B is a plan view showing the configuration of the quartz crystal vibrating piece.

In the gyro sensor 10c according to the present embodiment, the spacer 52c that is in contact with the base portion 14 is used.
In addition, the spacer 52 is located at a position where the support arm 20 and the drive arm 22 come into contact with each other.
f, 52 g is provided.

With such a configuration, not only the forming amount of the crystal vibrating piece 12 is adjusted, but also when the impact in the vertical direction (Z-axis direction) is applied to the crystal vibrating piece 12, the support arm 20.
Can be suppressed. For this reason, it is possible to prevent the drive arm 22 from coming into contact with the lid 50 due to deformation due to impact. In addition, about another structure, an effect | action, and an effect, it is the same as that of the gyro sensor 10, 10a, 10b which concerns on the 1st thru | or 3rd embodiment mentioned above.

10 ......... Gyro sensor, 12 ......... Crystal vibrating piece, 14 ......... Base, 16 (16a
16b) ... Detection arm, 18 (18a, 18b) ... Weight part, 20 ... Support arm, 22 (22a-22d) ... Drive arm, 24 (24a-24d) ......... Weight , 30... Support substrate, 32... Resin film, 34... Opening, 36 (36 a to 3
6f) ..... Inner lead, 38 .... IC, 40 ..... Package, 42 .... Bottom, 44, 46 ..... Stepped portion, 50 ..... Lid, 52 ..... Spacer.

Claims (5)

A physical quantity detection device having a structure in which a physical quantity detection element is pushed up to a lid side by an inner lead, and the physical quantity detection element is elastically supported in a cavity of a package,
A spacer is provided on the surface of the lid facing the physical quantity detection element,
The spacer is in contact with the physical quantity detection element in a state in which the package is sealed with the lid, and regulates the amount by which the physical quantity detection element is pushed up by the inner lead. The physical quantity detection device according to claim 1,
The physical quantity detection device according to claim 1, wherein the spacer is provided at a position in contact with a center between the physical quantity detection element supporting points by the inner leads. The physical quantity detection device according to claim 1,
At least three spacers are provided, and the physical quantity detection device is in contact with the physical quantity detection element at at least three points. The physical quantity detection device according to claim 1,
The physical quantity detection device according to claim 1, wherein the spacer has a structure in surface contact with the physical quantity detection element. The physical quantity detection device according to any one of claims 2 to 4,
The physical quantity detection element has a base, a pair of support arms extending from the base, a pair of detection arms, and a drive arm forming a pair extending from each of the support arms,
The physical quantity detection device according to claim 1, wherein the spacer is also provided at a position in contact with an intersection between the support arm and the drive arm.