JP2005308608A - Piezoelectric device, manufacturing method for piezoelectric device, and piezoelectric oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric device capable of transmitting Coriolis force generated when rotation is applied onto the piezoelectric device, without being disturbed, and capable of enlarging a detection displacement of a piezoelectric vibration piece for detecting the rotation to obtain desired detection sensitivity. <P>SOLUTION: A gyro sensor 100 of this piezoelectric device is constituted of a gyro vibration piece 10, a support base 20 of a support body for holding the gyro vibration piece 10, a connection part 21 located between the gyro vibration piece 10 and the support base 20, and formed by fixing layeredly a plurality of gold bumps 25 for connecting the gyro vibration piece 10 to the the support base 20, a package cage 22 for a ceramic or the like for fixing the support base 20 to be stored, and a lid body 23 for the package cage 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a piezoelectric device having a piezoelectric vibrating piece such as a gyro vibrating piece, a method for manufacturing the piezoelectric device, and a piezoelectric oscillator including the piezoelectric device.

  A conventional piezoelectric device will be described with reference to FIG. In a conventional piezoelectric device, for example, as described in Patent Document 1, a piezoelectric vibrating piece (hereinafter referred to as a “gyro vibrating piece”) 110 for detecting rotation is a connecting portion using a connecting material 111 such as a metal pin. And fixed to a support substrate 112 as an example of a support portion. The support substrate 112 is fixed to the package 113, and the open surface of the package 113 is sealed with the lid 114 fixed.

JP 2002-181550 A

  However, in the piezoelectric device shown in the background art described above, since the gyro vibrating piece 110 is firmly fixed to the support substrate 112 using a highly rigid connecting portion such as a metal pin, when the piezoelectric device is rotated, When the Coriolis force generated in is propagated to the detection part (detection arm) of the gyro vibrating piece, it passes through the part corresponding to the fixing part of the gyro vibrating piece to the support substrate. Inhibited in part. For this reason, the detection displacement of the Coriolis force in the gyro vibrating piece is small, and there is a problem that a desired detection sensitivity cannot be obtained.

In order to solve such a problem, the piezoelectric device of the present invention includes a piezoelectric vibrating piece that detects rotation, a support portion having an electrode that is electrically connected to the electrode of the piezoelectric vibrating piece, the electrode of the piezoelectric vibrating piece, and the support. A connecting portion that conducts at least a portion of the electrode, and the piezoelectric vibrating piece is supported by the supporting portion via the connecting portion, and the connecting portion includes a plurality of conductive particles. It is formed by overlapping.
According to the piezoelectric device of the present invention, the connecting portion between the piezoelectric vibrating piece for detecting rotation and the support portion is formed by overlapping the grains, so that the length of the connecting portion increases and the rigidity of the connecting portion decreases. Become. Therefore, when rotation is applied to the piezoelectric device, it is possible to achieve so-called flexible fixing in which the connection portion bends with the connection point with the support portion as a fulcrum. By this flexible fixing, the Coriolis force generated when rotation is applied to the piezoelectric device is transmitted without being hindered.
That is, it is possible to increase the detection displacement of the piezoelectric vibrating piece that detects rotation, and to obtain a desired detection sensitivity.

Moreover, it is desirable that the connecting portion is shaped by being pressed in the overlapping direction of the particles.
By doing so, since the connection portion is pressed, the connection surface of the connection portion with the piezoelectric vibrating piece or the support portion is shaped and flattened. The flat connection surface is connected to the piezoelectric vibrating reed or the support portion, and the connection area can be increased. That is, it is possible to increase the connection strength of the connection portion with respect to the piezoelectric vibrating piece or the support portion.

Moreover, it is desirable that the piezoelectric vibrating piece is supported by the connecting portion at a substantially central portion of the piezoelectric vibrating piece.
If it does in this way, when rotation will be added to a piezoelectric device, the connection part will become easy to bend about a connection point with a support part as a fulcrum. That is, it is possible to propagate without inhibiting the generated Coriolis force.

In addition, the piezoelectric vibrating piece and the support portion each have a plurality of the electrodes at a plurality of corresponding positions, the plurality of connection portions are provided in a state of being connected between the electrodes, and the piezoelectric vibrating piece is It is desirable that the support portion is supported by the plurality of connection portions in an arrangement state substantially parallel to the support portion.
In this way, since the piezoelectric vibrating piece is supported substantially parallel to the support portion by the plurality of connecting portions, it is easy to maintain the parallel state between the piezoelectric vibrating piece and the support portion, and Coriolis force detection sensitivity. Can be maintained in a large state.

  Moreover, the said granule is good also as being a metal bump.

  Further, the piezoelectric vibrating piece may be a gyro vibrating piece.

In addition, the piezoelectric device manufacturing method of the present invention includes a piezoelectric vibrating piece for detecting rotation, a support portion having an electrode connected to an electrode of the piezoelectric vibrating piece, an electrode of the piezoelectric vibrating piece, and an electrode of the support portion. A piezoelectric device having at least a connecting portion that is electrically connected to the support portion or the piezoelectric vibrating piece, and a plurality of conductive particles are stacked and fixed to form the connecting portion. And a step of pressing the open surface of the end of the connecting portion in the overlapping direction of the granules to shape the connecting portion.
According to the method for manufacturing a piezoelectric device of the present invention, the open surface at the end of the connection portion is pressed and shaped, and the unevenness of the open surface at the end of the connection portion is eliminated and flattened. It is possible to ensure a relatively large connection area of the connection portion with respect to. In other words, the connection reliability can be improved.

  It is also possible to provide a piezoelectric oscillator including the above-described piezoelectric device and a circuit element having a function of causing at least the oscillation of the piezoelectric vibrating piece constituting the piezoelectric device.

The best mode of a piezoelectric device according to the present invention will be described below with reference to the drawings. The present invention is not limited to the embodiments described later.
(First embodiment)

As a first embodiment of a piezoelectric device according to the present invention, a gyro sensor using a crystal vibrating piece (hereinafter referred to as “gyro vibrating piece”) for detecting a rotational angular velocity will be described with reference to the drawings. FIG. 1 is a schematic view of a gyro sensor showing a first embodiment. FIG. 1A is a plan view of the gyro sensor, and FIG. 1B is a cross-sectional view taken along the line AA ′ of FIG. FIG.1 (c) is the schematic which shows the detail of a support part.
== Gyro sensor configuration ==

The configuration of the gyro sensor will be described. The gyro sensor 100 is mounted and used on the object in order to detect the posture and position of an object such as an electronic device and a vehicle.
The gyro sensor 100 includes a gyro vibrating piece 10 that is a crystal piece, a support substrate 20 that is a support for holding the gyro vibrating piece 10, and between the gyro vibrating piece 10 and the support substrate 20. 20, a connection portion 21 that is electrically connected to the connection board 20, a package 22 made of ceramic or the like for fixing and storing the support substrate 20, and a lid 23 of the package 22.

== Description of gyro vibrating piece ==
Next, the gyro vibrating piece will be described in detail with reference to the drawings. FIG. 2 is a diagram illustrating the operation of the drive arm. FIG. 3 is a diagram illustrating the relationship between the operation of the drive arm and the Coriolis force. FIG. 4 is a diagram illustrating the operation of the detection arm.

First, the configuration of the gyro vibrating piece will be described.
As shown in FIG. 1, the gyro vibrating piece 10 used in the gyro sensor 100 is a first drive that constitutes a drive unit so as to operate in three modes, a conventionally known drive mode, detection mode, and spurious mode. The first drive arm 11A and the second drive arm 11B that are the arm part and the second drive arm part, the detection arm 12 that is the detection part, the arm support part 13 that is the arm support part, and the support part. And a support plate 14.

  One end of the arm support portion 13 is connected to the center of the first drive arm 11A, the other end is connected to the center of the second drive arm 11B, and the center of the detection arm 12 is the arm support portion. 13 are connected to coincide with the center. The support plate 14 is a plate-like portion having a predetermined area including a connection point between the arm support portion 13 and the detection arm 12.

Next, the operation of the gyro vibrating piece will be described.
As shown in FIG. 2A, the first and second drive arms 11A and 11B are plate portions each having a predetermined length extending in the Y direction shown in the drawing, that is, parallel to each other. The first and second drive arms 11A and 11B respond to rotation given with the Z direction shown in the figure as a rotation axis, which is one of the above-described fluctuations of the posture of the object during vibration along the X direction shown in the figure. Thus, a Coriolis force corresponding to the magnitude of the rotational angular velocity is generated.

  As shown in FIGS. 2A to 2C, the drive arm 11 </ b> A vibrates by a bending operation with its center as an axis, and more specifically, the portion closer to the end thereof becomes larger along the X direction. It vibrates by being deformed into an uneven shape that is displaced. As shown in FIG. 3, the drive arm 11 </ b> B vibrates by a bending operation into a shape that is in a line-symmetric relationship with the uneven shape that the drive arm 11 </ b> A deforms.

  As shown in FIG. 3, the first drive arm 11A is changed from the shape shown by the two-dot chain line to the shape shown by the solid line, and the second drive arm 11B is also shown by the two-dot chain line. When the shape is changed from the shape shown by the solid line to the shape indicated by the solid line and the clockwise rotation in the paper is applied, the Coriolis force is generated in the direction indicated by the arrows 19A and 19B in FIG. On the other hand, the first drive arm 11A is changed from the shape indicated by the solid line to the shape indicated by the two-dot chain line, and the second drive arm 11B is indicated by the two-dot chain line from the shape indicated by the solid line. When changing to the shape, if a clockwise rotation in the paper is applied, the Coriolis force is generated in the direction opposite to the arrows 19A and 19B in FIG.

  Similar to the first drive arm 11A and the second drive arm 11B, the detection arm 12 is a plate portion having a predetermined length that extends along the Y direction shown in the figure. That is, the first drive arm 11A, the second drive arm 11B, and the detection arm 12 are parallel to each other. The detection arm 12 transmits the Coriolis force transmitted from the first and second drive arms 11A and 11B via the arm support portion 13 so as to detect the Coriolis force acting on the first and second drive arms 11A and 11B. In response to the vibration, the vibration corresponding to the magnitude of the Coriolis force is performed.

As shown in FIGS. 4A to 4C, the detection arm 12 is similar to the bending operation of the first and second drive arms 11A and 11B shown in FIGS. A bending operation of deforming into an approximately S shape and an inverted S shape is performed. The magnitude of the Coriolis force is obtained by detecting an electric signal generated by the bending motion rotation by the detection arm 12, and thereby the magnitude of the rotational angular velocity applied to the article is recognized.
== Description of connection part ==

Next, the connection part 21 is demonstrated.
As shown in FIG. 1, the connection between the gyro vibrating piece 10 and the support substrate 20 is performed near the center 24 of the plane of the gyro vibrating piece. The connecting portion 21 is composed of four connecting members 21a, 21b, 21c, and 21d formed in a column shape. Each of the connecting members 21a, 21b, 21c, and 21d is formed by overlapping and connecting gold bumps 25 (stud bumps) as an example of the grains.

  Here, the connection for overlaying the gold bumps 25 will be described using the connection member 21c as an example. The connection for superimposing the gold bumps 25 is performed using, for example, a gold eutectic phenomenon that occurs by pressing the gold bumps at a high temperature (approximately 150 ° C. or higher). First, the lowermost gold bump 25 a is connected on the support substrate 20. Subsequently, the gold bump 25b of the next layer is connected to the gold bump 25a, and thereafter, connected in order of 25c, 25d, and 25e. The other connection members 21a, 21b, and 21d are also formed by the same connection as described above.

  The connection between the gyro vibrating piece 10 and the connection portion 21 is performed by using a eutectic phenomenon between the electrode film (not shown) of the gyro vibrating piece and the gold bump 25 constituting the connection portion 21. The eutectic phenomenon is the same phenomenon as the superposition of the gold bumps 25 described above.

  The connection between the support substrate 20 and the connection portion 21 is similar to the connection between the gyro vibrating piece 10 and the connection portion 21 described above, and the electrodes (not shown) of the support substrate 20 and the gold bumps 25 constituting the connection portion 21. By using the eutectic phenomenon.

  In addition, although the connection part 21 demonstrated with the structure of the four connection members 21a, 21b, 21c, and 21d formed in the columnar shape, it is not restricted to this, The number of connection members should just be one piece or 2 pieces or more.

  Further, the gold bump 25 has been described using a stud bump as an example. However, the gold bump 25 is not limited thereto, and may be a plated bump that forms the gold bump 25 by plating, for example.

  Moreover, although the number of the gold bumps 25 constituting the connection members 21a to 21d has been described as a so-called five-tiered structure using five gold bumps, the present invention is not limited to this, and the flexibility required for the connection members 21a to 21d. The number is not limited as long as the number can be secured.

  Further, the connection between the support substrate 20 and the connection portion 21 is not a eutectic phenomenon, and for example, a conductive adhesive (not shown) or the like may be used. The same applies to the connection between the connecting portion 21 and the gyro vibrating piece 10, and the connection may be made using a conductive adhesive or the like.

  Further, after fixing the gold bumps 25 in an overlapped state, the pressing in the overlapping direction for shaping is not limited to being performed with one end connected to the gyro vibrating piece 10 or the support substrate 20. A method of connecting both ends of the connection members 21 a to 21 d to the gyro vibrating piece 10 and the support substrate 20 after pressing in the overlapping direction by a press machine (not shown) or the like may be used.

According to the first embodiment described above, since the connection member 21 is formed using the connection members 21a to 21d formed by overlapping the gold bumps 25, the length of the connection member 21 is increased. For this reason, the connection part 21 becomes less rigid in the direction orthogonal to the length direction of the connection part 21 and has flexibility. Therefore, the connection between the gyro vibrating piece 10 and the support substrate 20 is not a strong connection but can be connected with flexibility. The flexibility of the connecting portion 21 can prevent the propagation of Coriolis force from being hindered. That is, when rotation is applied to the gyro sensor 100, the Coriolis force transmitted from the first and second drive arms 11A and 11B to the detection arm 12 through the arm support portion 13 and the support plate 14 is provided on the support plate 14. It can propagate without being obstructed by the connected part. Due to the propagation of the Coriolis force that is not hindered, the detection displacement of the gyro vibrating piece 10 can be increased, and a desired detection sensitivity can be obtained.
(Second embodiment)

  A method for manufacturing a piezoelectric device according to the present invention will be described with reference to the drawings, taking a method for manufacturing a gyro sensor as an example. FIG. 5 is a diagram illustrating a process flow showing the formation of the connection member at the connection part of the gyro sensor.

  First, the connection member 30 which comprises a connection part shown in Fig.5 (a) is formed. The connection member 30 as an example of a plurality of connection members is formed by overlapping and connecting the gold bumps 30a to 30e on one surface of the support substrate 31 as a support portion. More specifically, first, the lowermost gold bump 30 a is connected to one surface of the support substrate 31. Subsequently, the gold bump 30b of the next layer is joined to the gold bump 30a, and thereafter, the respective gold bumps are connected in the order of 30c, 30d, and 30e. The other connection members 33 are also formed by the same connection as described above.

  The support substrate 31 and the gold bump 30a are connected by using a eutectic phenomenon between gold of a gold electrode provided on an electrode wiring of the support substrate 31 (not shown) and gold of the gold bump 30a. The respective gold bumps 30a, 30b, 30c, 30d, and 30e are connected by using a eutectic phenomenon of gold constituting each gold bump.

  Subsequently, as shown in FIG. 5B, the pressing member 32 is pushed against the open surfaces (hereinafter referred to as “open surfaces”) of the ends of the connection members 30 and 33 provided in a plurality (two in this description). The open surfaces of the contact members 30 and 33 (shown by arrows in the figure) are shaped. The pressing surface 34 of the pressing member 32 has no unevenness and is set in a parallel relationship with the support substrate 31. The pressing amount can be arbitrarily set as long as shaping is possible.

  After finishing the shaping of the plurality of connection members 30 and 33, as shown in FIG. 5C, the pressing member 32 moves in a direction away from the connection members 30 and 33 (in the direction of the arrow in the figure), and the connection member Leave 30 and 33. The open surfaces P <b> 1 and P <b> 2 of the support members 30 and 33 are not uneven, have a constant height from the support substrate 31, and are parallel to the support substrate 31.

  Subsequently, the gyro vibrating piece 10 is joined to the open surfaces P1, P2 of the shaped connection members 30, 33. The bonding is performed by using a eutectic phenomenon that forms an electrode film of the gyro vibrating piece 10 (not shown), for example, a metal such as gold and gold of the gold bump 30e.

  In the above description, the connection members 30 and 33 are formed on the support substrate 31. However, the present invention is not limited to this, and after the connection members 30 and 33 are formed on one surface of the gyro vibrating piece 10. The open surfaces of the connection members 30 and 33 may be shaped, and then the open surfaces of the connection members 30 and 33 and the support substrate 31 may be joined.

  Moreover, although the connection member demonstrated by the structure using the two connection members of the connection member 30 and the connection member 33, the number of connection members is not restricted to this, What is necessary is just one or two or more.

  According to the second embodiment described above, by pressing and shaping the open surfaces P1 and P2 of the connecting portion, the open surfaces P1 and P2 of the connecting portion have no irregularities and become flat. Therefore, the non-contact portion of the connection portion between the gyro vibrating piece 10 and the support substrate 31 due to the unevenness of the open surface of the connection portion can be eliminated, and a relatively large connection area can be secured.

  In addition to the effects described above, the height from the support substrate 31 to the open surfaces of the plurality of connection portions 30 and 33 can be made uniform, and the support substrate 31 and the gyro vibrating piece 10 can be kept parallel. It becomes possible.

Furthermore, the number of gold bumps to be stacked can be set easily and arbitrarily. That is, the resonance frequency of the gyro vibrating piece 10 can be easily changed by changing the length of the connecting portion easily and arbitrarily.
(Third embodiment)

As a third embodiment of the piezoelectric device according to the present invention, a piezoelectric oscillator using a gyro vibrating piece as an example of a piezoelectric vibrating piece and a circuit element including the oscillation circuit will be described with reference to the drawings. FIG. 6 is a schematic cross-sectional view of the piezoelectric oscillator showing the third embodiment.
== Configuration of piezoelectric oscillator ==

The configuration of the piezoelectric oscillator will be described. The piezoelectric oscillator 50 is joined by a gyro vibrating piece 10 using quartz crystal, which is an example of a piezoelectric vibrating piece, and a connecting portion 41 formed by superposing the gyro vibrating piece 10 and a gold bump, and oscillates at least the gyro vibrating piece 10. Circuit element 40, a package 42 made of ceramic or the like, and a lid 43 of the package 42.
== Description of gyro vibrating piece ==

The gyro vibrating piece 10 is the same as that described in detail in the first embodiment. Therefore, the description in this embodiment is omitted.
== Description of circuit elements ==

Next, circuit elements will be described.
The circuit element 40 is, for example, a semiconductor chip or a circuit board, and has a function of oscillating the gyro vibrating piece 10, a function of detecting Coriolis force, a function of outputting the detected Coriolis force, and the like. In the circuit element 40, a connection terminal 44 is formed on one surface using aluminum or the like in order to connect to the gyro vibrating piece 10. The connection terminal 44 is connected to various electric circuits such as a drive circuit (not shown) in the circuit element 40, and further connected to an external terminal (not shown) of the package 42. .
== Connection between circuit element and gyro vibrating piece ==

Next, an example of connection between the circuit element 40 and the gyro vibrating piece 10 will be described.
The connection between the circuit element 40 and the gyro vibrating piece 10 is performed by sandwiching a connection portion 41 formed by overlapping gold bumps between the connection terminal 44 formed on the circuit element 40 and the connection pad 45 of the gyro vibrating piece 10. Press to connect while heating. It is also possible to connect while applying ultrasonic waves simultaneously with heating and pressurization.
The above-described connections are made of aluminum forming the connection terminals 44 of the circuit element 40 and gold of gold bumps forming the connection portions 41, and gold forming the connection pads 45 of the gyro vibrating piece 10 and gold forming the connection portions 41. Each bump is connected by eutectic.

  According to the third embodiment described above, the piezoelectric oscillator 50 in which the gyro vibrating piece 10 as an example of the piezoelectric vibrating piece and the circuit element 40 having the function of causing at least the oscillation of the gyro vibrating piece 10 are housed in one package is provided. can do. That is, the space for attaching the gyro vibrating piece 10 and the circuit element 40 can be reduced.

Schematic which shows the gyro sensor in 1st embodiment. The top view which shows operation | movement of the drive arm of a gyro vibrating piece. The top view which shows the relationship between operation | movement of the drive arm of a gyro vibrating piece, and Coriolis force. The top view which shows operation | movement of the detection arm of a gyro vibrating piece. Explanatory drawing of the process flow which shows formation of the connection member in the connection part of the gyro sensor in 2nd embodiment. The schematic sectional side view which shows the piezoelectric oscillator in 3rd embodiment. The schematic sectional side view of the conventional piezoelectric device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Gyro vibrating piece as a piezoelectric vibrating piece, 11A ... 1st drive arm, 11B ... 2nd drive arm, 12 ... Detection arm, 13 ... Arm support part, 14 ... Support plate, 20 ... Support as a support part Substrate, 21 ... connection portion, 21a to 21d ... support member, 22 ... package, 23 ... lid, 24 ... center of plane of gyro vibrating piece, 25 ... gold bump as granule, 25a to 25e ... Gold bumps 30, 33... Connection members as connection parts, 30 a to 30 e. Gold bumps as particles, 50. Piezoelectric oscillator, 100.

Claims (8)

A piezoelectric vibrating piece for detecting rotation;
A support portion having an electrode connected to the electrode of the piezoelectric vibrating piece;
A connecting portion that conducts at least the electrode of the piezoelectric vibrating piece and the electrode of the supporting portion;
The piezoelectric vibrating piece is supported by the support part via the connection part,
The piezoelectric device is characterized in that the connection portion is formed by overlapping a plurality of conductive particles. The piezoelectric device according to claim 1.
The piezoelectric device is characterized in that the connecting portion is shaped by being pressed in a direction in which the particles are overlapped. The piezoelectric device according to claim 1.
The piezoelectric device is characterized in that the piezoelectric vibrating piece is supported by the connecting portion at a substantially central portion of the piezoelectric vibrating piece. The piezoelectric device according to claim 1.
The piezoelectric vibrating piece and the support portion each have a plurality of the electrodes at a plurality of corresponding positions, and the plurality of connection portions are provided in a state of being connected between the electrodes,
The piezoelectric vibrating piece is supported by the support portion in an arrangement state substantially parallel to the support portion via the plurality of connection portions. The piezoelectric device according to claim 1.
The piezoelectric device, wherein the particles are metal bumps. The piezoelectric device according to claim 1.
The piezoelectric device is characterized in that the piezoelectric vibrating piece is a gyro vibrating piece. Piezoelectric device having a piezoelectric vibrating piece that detects rotation, a support portion having an electrode that is electrically connected to the electrode of the piezoelectric vibrating piece, and a connection portion that is at least electrically connected to the electrode of the piezoelectric vibrating piece and the electrode of the support portion A manufacturing method of
A step of stacking and fixing a plurality of conductive particles on the support portion or the piezoelectric vibrating piece to form the connection portion;
Pressing the open surface of the end of the connecting portion in the overlapping direction of the granules, and shaping the connecting portion;
A method for manufacturing a piezoelectric device, comprising: The piezoelectric device according to any one of claims 1 to 6,
A circuit element having a function of oscillating at least the piezoelectric vibrating reed constituting the piezoelectric device;
A piezoelectric oscillator comprising:

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