JP2019057871A - Crystal device - Google Patents

Abstract

A quartz device having excellent characteristics using a pedestal made of quartz is provided. A crystal device 10 includes a crystal piece 11 having excitation electrodes 11a and lead electrodes 11b on the front and back surfaces, a container 13 for housing the crystal piece, and a pedestal 15 provided between the crystal piece and the container. The adhesive 17 fixing the crystal piece to the pedestal, the conductive adhesive 19 fixing the pedestal to the container in a region including the center of gravity thereof, and the conductive adhesive provided in the container to heat the conductive adhesive It includes a heat conduction pattern 21 for transmitting, a wiring pattern 23 provided in the container, and a wire bonding structure 25 connecting the wiring pattern and the extraction electrode. [Selection] Figure 1

Description

  The present invention relates to a crystal device having a pedestal made of crystal.

  In various electronic devices such as mobile phones and personal computers, crystal devices such as crystal resonators and crystal oscillators are frequently used for frequency selection and control.

  On the other hand, there is an increasing demand for improvement in frequency stability, vibration resistance, impact resistance, and the like for such a crystal device. For example, Patent Document 1 discloses a technique for maintaining good vibration characteristics by eliminating the influence of a difference in thermal expansion coefficient of components of a crystal resonator. Specifically, a structure is disclosed in which a quartz base is interposed between crystal pieces when they are mounted on a ceramic package (FIG. 1 of Patent Document 1). Furthermore, it is disclosed that the connection between the package and the pedestal is performed by wire bonding in order to achieve conduction between the package and the pedestal (FIG. 2 of Patent Document 1, etc.).

JP 2009-253883 A

  However, in the case of the structure disclosed in Patent Document 1, the position where the package and the base are fixed is one end along the first direction of the base, and the position where the base and the crystal piece are fixed is the first position of the base. The other end along the direction 1. Therefore, when attention is paid to the pedestal and the package, the pedestal is fixed to the package at one end thereof. In such a fixed position, since the pedestal is fixed to the package in a cantilevered state, the pedestal may bend or swing around the fixed point, and there is a concern that the crystal piece may be affected.

In the case of the structure using wire bonding disclosed in Patent Document 1, a pad for wire bonding is provided on the pedestal. Then, the base and the crystal piece are connected by a conductive adhesive, and the base and the package are connected by wire bonding. That is, the crystal piece is not directly connected to the package by wire bonding. Therefore, the structure of the pedestal becomes complicated and a conductive adhesive is required, which is disadvantageous in terms of manufacturing cost.
The present application has been made in view of the above points. Accordingly, an object of the present invention is a quartz crystal device using a pedestal made of quartz crystal, which has a structure capable of improving characteristics and easily reducing costs. Is to provide a crystal device.

In order to achieve this object, the quartz crystal device of the present invention is
A crystal piece having an excitation electrode and an extraction electrode;
A container containing the crystal piece;
A pedestal provided between the crystal piece and the container;
An adhesive fixing the crystal piece to the pedestal;
A conductive adhesive fixing the pedestal to the container in a region including its center of gravity;
A heat conduction pattern provided in the container and conducting heat to the conductive adhesive;
A wiring pattern provided in the container;
And a wire bonding structure connecting the wiring pattern and the extraction electrode.

In practicing the present invention, an adhesive that fixes the crystal piece to the pedestal is an insulating adhesive, and this adhesive is preferably provided so as to fix the crystal piece to the pedestal in one region. In this case, for example, the crystal piece can be fixed to the pedestal only in a portion between the two polar extraction electrodes, that is, the crystal piece only in one region between the two extraction electrodes. .
In practicing the present invention, it is preferable that the pedestal has a step structure for separating a region to which the adhesive for fixing the crystal piece is applied and a region other than the region. This makes it difficult for the adhesive to flow into the center of vibration of the crystal piece, so that deterioration of vibration characteristics can be prevented.
The pedestal is preferably made of quartz. If it carries out like this, since physical properties, such as a thermal expansion coefficient of a base, become close to a crystal piece, the bad influence resulting from the difference in each physical property of a base and a crystal piece can be reduced.
In carrying out the present invention, it is preferable that the crystal piece has a quadrangular planar shape, and the adhesive that fixes the crystal piece to the pedestal is provided on one short side of the crystal piece. In this case, since the crystal piece is fixed to the pedestal in a cantilevered state, the influence of the fixing portion on the vibration center portion of the crystal piece can be reduced.

According to the present invention, since the pedestal is fixed to the container in a region including the center of gravity, the pedestal is less likely to bend, vibrate, etc., compared to the case where the pedestal is cantilevered. Is unlikely to occur.
In addition, since the pedestal is fixed to the container with a conductive adhesive and a heat conduction pattern is provided, for example, when the present invention is applied to an oscillator with a thermostat, the temperature of the thermostat is easily transmitted to the crystal piece. . For this reason, an oscillation source with a thermostat can provide an oscillation source with excellent frequency stability.
In addition, since it has a wire bonding structure that connects the lead electrode of the crystal piece and the wiring pattern of the container, the pedestal can be constructed with a simple structure, so that the cost can be reduced. The effect of the fixing structure to the crystal piece can be reduced compared to the case of fixing with a.

(A), (B), (C) is a figure for demonstrating the crystal device 10 of 1st Embodiment. It is a figure for demonstrating the crystal device of 2nd Embodiment. It is a figure for demonstrating the crystal device of 3rd Embodiment. It is a figure for demonstrating the crystal device of 4th Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. Each figure used for explanation is only shown to such an extent that these inventions can be understood. Moreover, in each figure used for description, about the same component, it attaches | subjects and shows the same number, The description may be abbreviate | omitted. Further, the shapes, dimensions, materials, and the like described in the following embodiments are merely preferred examples within the scope of the present invention. Therefore, the present invention is not limited only to the following embodiments.

1. First Embodiment FIGS. 1A, 1 </ b> B, and 1 </ b> C are diagrams illustrating a crystal device 10 according to a first embodiment. 1A is a plan view showing the crystal device 10, FIG. 1B is a cross-sectional view taken along the line P-P in FIG. 1A, and FIG. It is sectional drawing along the QQ line. In addition, illustration of the lid member is omitted in FIG. The crystal device 10 corresponds to an embodiment as a crystal resonator.

The crystal device 10 according to the first embodiment includes a crystal piece 11, a container 13, a base 15, an adhesive 17, a conductive adhesive 19, a heat conductive pattern 21, a wiring pattern 23, and a wire bonding structure 25. And a lid member 27.
In this case, the crystal piece 11 has a quadrangular planar shape, specifically a rectangular shape. This crystal piece is, for example, a so-called two-turn crystal piece represented by SC cut or an AT cut crystal piece. The crystal piece 11 has excitation electrodes 11a and extraction electrodes 11b on the front and back surfaces. The extraction electrode 11b is extracted from the excitation electrode 11a in this case to one side of the crystal piece 11 and to both end regions of this one side.
The container 13 accommodates the crystal piece 11. The container 13 in this case has a recess 13a for accommodating the crystal piece 11, and can be constituted by, for example, a ceramic package.

The pedestal 15 is provided between the crystal piece 11 and the container 13. The constituent material of the base 15 can be any suitable material such as quartz, ceramics, and glass. However, since the physical properties of the pedestal 15 are preferably closer to the physical properties of the crystal piece 11 for reasons such as matching of thermal expansion coefficients, the pedestal is also preferably made of quartz. In addition, the base 15 in this case is a base having a step structure 15a for distinguishing a region where the adhesive 17 for fixing the crystal piece 11 is applied and a region other than the region. The pedestal 15 in this example is assumed to have a step structure 15a that is thicker at both side portions in the long side direction. The pedestal 15 may be thick only at one end side, but a symmetrical structure with thickened both ends is preferred. With such a symmetric structure, the pedestal can be set in the container without worrying about the orientation of the pedestal when the crystal device is manufactured. Since the step structure 15a is provided, even when the adhesive 17 flows to the center side of the crystal piece 11 when the crystal device is manufactured, the adhesive 17 is separated from the crystal piece 11 on the lower side of the step structure 15a. Does not adhere to.
The adhesive 17 fixes the crystal piece 11 to the pedestal 15. In the case of this example, the crystal piece 11 is bonded to the pedestal 15 in a region near the center of one side of the crystal piece 11. In this case, the adhesive 17 is an insulating adhesive. If it is an insulating adhesive, even if it spans between bipolar extraction electrodes, a short circuit between the electrodes does not occur. In addition, since the adhesive 17 is bonded and fixed to the pedestal 15 in one region near the center of one side of the crystal 11, the adhesive 17 has stress compared to the case where the adhesive is provided at a plurality of locations. Etc., and the influence of the adhesive on the crystal piece can be reduced.

The conductive adhesive 19 fixes the pedestal 15 to the container 13 in a region including its center of gravity. The one region including the center of gravity is a necessary minimum area that can secure the bonding strength and does not apply the stress of the adhesive 19 to the pedestal more than necessary. The reason why the conductive adhesive is used is to efficiently transfer the heat guided to the conductive adhesive 19 from the outside by a heat conductive pattern 21 described later to the base 15. The conductive adhesive 19 can be selected and used from a silicone type, an epoxy type, a polyimide type, etc., which are often used in the manufacture of crystal resonators.
If the crystal device is a crystal oscillator with a thermostatic chamber, the heat conduction pattern 21 is to transmit heat from the heater to the base 15 (for details, refer to the fourth embodiment described later). The heat conductive pattern 21 can be formed at the same time when the ceramic package as the container 13 is manufactured. Specifically, it can be constituted by a conductive pattern that can be manufactured at the time of ceramic package formation and via wiring that can be formed in the container 13.

The wiring pattern 23 serves as a wibon pad on the container 13 side. The wiring pattern 23 is typically connected to an external connection terminal 13 b provided on the outer bottom surface of the container 13. In order to facilitate wire bonding, a part of the container 13 is raised so that the height is close to the height of the upper surface of the crystal piece 11, and the wiring pattern 23 is provided at the raised portion. Is good.
The wire bonding structure 25 connects the extraction electrode 11b of the crystal piece 11 and the wiring pattern 23 on the container 13 side. This wire bonding structure 25 can be realized by a known wire bonding technique.
The lid member 27 is joined to the container 13 at the top surface of the bank portion around the recess 13a of the container 13 to seal the container. Any structure can be used according to the sealing method.
According to the crystal device 10, the effects described in the column of the effects of the invention can be obtained.

2. 2nd Embodiment In 1st Embodiment, although the adhesive agent 17 and the wire bonding structure 25 were concentrated and provided in the one side of the crystal piece 11, the position which provides these is not restricted to this, Others The position of may be good.
FIG. 2 is an example thereof, and is a plan view showing a crystal device 30 according to the second embodiment. In the crystal device 30 according to the second embodiment, one of the adhesive 17 and the wire bonding structure 25 is provided on the first short side, and the other is the second short side facing the first short side. It is provided on the side. In the case of this structure, it is considered that each stress of the adhesive 17 and the wire bonding structure 25 can be dispersed.

3. Third Embodiment In each of the first and second embodiments, the wire bonding structure 25 is provided in both end regions along the first short side of the crystal piece 11, but the position where the wire bonding structure 25 is provided is this. It is not limited to this, and other positions may be used.
FIG. 3 is an example thereof, and is a plan view showing a crystal device 40 of the third embodiment. In the crystal device 40 of the third embodiment, the lead electrode 11b itself of the crystal piece 11 is provided close to one corner side of the crystal piece 11, and the wire bonding structure 25 itself also follows the position of this lead wiring. The crystal piece 11 is provided close to one corner side. Correspondingly, the adhesive 17 itself is also provided close to one corner side of the crystal piece 11 from the center of one short side of the crystal piece. That is, in this example, the adhesive 17 and the wire bonding structure 25 are provided so as to be concentrated in a region along the first short side of the crystal piece and on one side of the center of the short side.
In the case of the crystal device 40 of the third embodiment, each of the adhesive 17 and the wire bonding structure 25 is concentrated on one corner side of the crystal piece 11, so that each position is provided when each is provided at a different position. It is thought that the effect of stress applied to the crystal piece can be reduced.

4). Fourth Embodiment (Crystal Oscillator Embodiment)
Next, an example in which the present invention is applied to a crystal device as an oscillator will be described. FIG. 4 is an explanatory diagram in which components as an oscillator are added to the cross-sectional view corresponding to FIG. In FIG. 4, symbols that are not necessary for the description of the present embodiment are omitted from the symbols that indicate the respective components.

In addition to the configurations of the piezoelectric devices 10, 30, and 40 of the first to third embodiments, the crystal device 50 of this embodiment includes an oscillation circuit 51 for the crystal piece 11 and a container 13 that contains the crystal piece 11. A temperature control circuit 55 including a heater 53 for heating. However, the external connection terminal 13 b connected to the heat conductive pattern 21 is connected to the heater 53.
In the case of this crystal device 50 as an oscillator, the heat of the heater 53 is transmitted to the pedestal 15 via the external connection terminal 13 b and the heat conductive pattern 21, and the radiant heat from the pedestal 15 reaches the crystal piece 11. Therefore, for example, a temperature-compensated crystal oscillator, which is excellent in the thermal response to the crystal resonator element, can be realized. So

5. Other Embodiments In the above-described embodiments, the structure in which the crystal piece is cantilever-supported has been shown. However, the present invention can also be applied to the case of a both-end support structure in which the crystal piece is supported by two opposing sides. Moreover, although the example which used the container which has a recessed part as a container and used the flat cover member as a cover member was demonstrated, it applies also to the thing using a flat container and using a cap-shaped cover member as a cover member it can.

10: Crystal device of embodiment, 11: Crystal resonator element,
10: Quartz device in the first embodiment, 11: Quartz piece 11a: Excitation electrode, 11b: Extraction electrode,
13: Container, 13a: Recess,
13b: External connection terminal 15: Pedestal 15a: Step structure 17, 17x: Adhesive 19: Conductive adhesive 21: Heat conduction pattern 23: Wiring pattern 25: Wire bonding structure 27: Lid member 30: Second Crystal device of the embodiment 40: Crystal device of the third embodiment 50: Crystal device of the fourth embodiment (crystal oscillator)
51: Oscillator circuit 53: Heater 55: Temperature control circuit

Claims (5)

A crystal piece having an excitation electrode and an extraction electrode;
A container containing the crystal piece;
A pedestal provided between the crystal piece and the container;
An adhesive fixing the crystal piece to the pedestal;
A conductive adhesive fixing the pedestal to the container in a region including its center of gravity;
A heat conduction pattern provided in the container and conducting heat to the conductive adhesive;
A wiring pattern provided in the container;
And a wire bonding structure connecting the wiring pattern and the extraction electrode.   2. The crystal device according to claim 1, wherein an adhesive that fixes the crystal piece to the pedestal is an insulating adhesive, and the crystal piece is fixed to the pedestal in one region by the adhesive.   3. The crystal device according to claim 1, wherein the pedestal has a step structure for distinguishing a region to which an adhesive for fixing the crystal piece is applied from other regions. 4.   The crystal device according to claim 1, wherein the pedestal is made of crystal.   5. A crystal device according to claim 1, an oscillation circuit for the crystal piece, and a temperature control circuit including a heater that heats the container containing the crystal piece. A crystal device as a featured oscillator.

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