JPH02134009A - Structure of piezoelectric device package - Google Patents

Abstract

PURPOSE:To attain superminiature structure for a piezoelectric device and to prevent leakage of a thickness vibration energy by limiting number of rigid fixed points of a piezoelectric substrate and applying wire bonding to the connection between an electrode lead of the piezoelectric device and a lead terminal penetrated through a package containing the lead air-tightly. CONSTITUTION:The circumferential ridge of a piezoelectric device (crystal resonator) is fixed at as a few points as possible, desirably at one point as a cunti-lever in a package 7. That is, the end of an electrode lead 2 of the crystal resonator 1 and a conductor pad are adhered by a conductive adhesives, the resonator 1 is fixed as cunti-lever in the package 7 to apply electric connection. On the other hand, other electrode lead 2' of the resonator 1 is connected electrically to a conductor pad 13 and a wire 14 exposed to the surface of a land 12 provided to other corner of the package 7. Thus, when the resonator 1 is formed in superminiature, since part of the electric connection is subject to wire bonding, the leakage of the vibration energy is prevented, while miniaturization and thin profile of the piezoelectric device are implemented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of a pancage that houses a piezoelectric device, particularly a micro-sized piezoelectric resonator.

(Prior Art) A piezoelectric device, particularly a piezoelectric device that utilizes thickness vibration, is conventionally manufactured by attaching, for example, an electrode lead portion 2.2 of a crystal resonator 1 to a base near an edge of a crystal substrate, as shown in FIG. 3(a). 3
Lead member 4. Conductor clip 5 at the tip of 4.
．． At the same time, mechanically fixing the crystal substrate and electrically connecting the electrode lead portion 2.2 and the conductor clip 5.5 by holding the crystal substrate with conductive adhesive 6.6 or attaching it with a conductive adhesive 6.6, or As shown in bl, the piezoelectric vibrator 1 is placed in a flat package 7 with its main surface horizontally,
'J-de part 2.2? : It has been common practice to hermetically penetrate the wall of the package 7 and bond and fix the lead terminals 8, 8 exposed at appropriate positions inside the package 7 with a conductive adhesive 6.6.

However, as the demands for smaller and thinner electronic devices have become stricter, the electronic components used in these devices are becoming more and more compact.
As piezoelectric devices, which are the mainstay of piezoelectric devices, are now required to be ultra-miniaturized, the size of piezoelectric substrates must also be reduced. If it is relatively rigidly fixed at various locations around the periphery, vibration energy leaks from the fixed portion, resulting in a reduction in the Q of resonance.

(Object of the Invention) The present invention has been made in order to eliminate the defects of the conventional piezoelectric device holding structure as described above. The purpose of the present invention is to provide a piezoelectric device vanocage having a structure suitable for connection with a lead terminal that hermetically passes through a package containing a piezoelectric device by wire bonding.

(Summary of the Invention) In order to achieve the above-mentioned objects, a piezoelectric device package according to the second invention has the following configuration.

That is, in order to connect the periphery of the piezoelectric device in a cantilevered manner at as few points as possible, preferably at one point, in the package and to the XfUIJ-domain of the piezoelectric device by wire bonding, the land is passed through the package wall in an airtight manner. A fine gap is provided between the exposed lead terminal pad and the back surface of the electrode lead portion of the piezoelectric device to form a piezoelectric substrate support land.

(Example) The present invention will be described in detail below based on an example shown in the drawings.

FIGS. 1(a) and 1(b) are a plan view and an AA cross-sectional view showing an embodiment of the piezoelectric device package according to the present invention, respectively, in which a crystal resonator is placed in one corner of the flat back; A land 9 is provided at the end of the one-electrode board portion 2 to fix it, and a conductor pad 10 is exposed on the surface of the land 9. The pad 10 has an extended portion 11 that passes through the package wall in an airtight manner, and is attached to an appropriate location on the outer wall of the package. Configure the leads to expose them to the

By bonding the ends of the electrode leads 2 of the crystal resonator 1 and the conductive pads 10 with a conductive adhesive 6, the crystal resonator 1 is cantilevered and fixed in the pano cage 7, and an electrical connection is established. conduct.

On the other hand, the other electrode lead portion 2' of the crystal resonator 1 is
The conductor pad 13 exposed on the surface of the land 12 provided at the other corner of the crystal cage 7 is electrically connected to the wire 14. A piezoelectric device support land 15 is provided on the back surface of the necessary electrode lead portion 2' to temporarily support it.

Similarly, it is obvious that the surface level of the support lands 150 should be set slightly lower than the back surface of the crystal resonator 1 supported in a cantilever manner so that they do not come into contact with each other after the wire bonding process is completed.

The extended portion of the pad 13 exposed on the surface of the mold 12 passes through the package wall in a hermetic manner and constitutes another wall portion 16, which requires no particular explanation.

By doing so, if the crystal resonator is ultra-small, some of the electrical connections are made by wire bonding, so that the leakage of vibration energy is small and a reduction in the Q of resonance can be prevented.

FIGS. 2(a) and 2(bl) are a plan view and a sectional view taken along the line B-B, respectively, showing an embodiment applied to the dual-mode piezoelectric filter of the present invention.

As is well known, the dual-mode piezoelectric filter has divided electrodes 18 and 18 on 17,000 planes of a piezoelectric substrate, and a grounding electrode 19 on the back of the piezoelectric substrate, and utilizes vibrations in different symmetric and anti-symmetric modes that occur when excited. It consists of a bandpass filter.

When such a piezoelectric filter is miniaturized, if the electrode lead parts extending from the three electrodes are rigidly fixed at their ends, the vibration energy of the two modes will leak from the fixed points, resulting in the filter's Not only does the insertion loss increase, but the cutoff characteristics also deteriorate.

In order to solve this problem, lands 12.12 and conductor pads 13.13 exposed on the surface of the lands 12.12 for connecting with the electrode lead parts 20.20 of the divided electrodes 18.18 by wire bonding, respectively, are provided in the package 7. , lands 15'', 15 for supporting the back surface of the electrode lead portion 20.20 of the piezoelectric substrate 1, and the electrode lead portion 2 of the ground electrode 19.
Land 9 for mechanically fixing 1 and electrically connecting
The piezoelectric filter 17 is cantilevered by the end of the lead 21 of the ground electrode 19, and the other two electrode leads 20, 20 are provided.
The conductor pads 13 and 13 are connected by wire bonding respectively.
You just have to connect it electrically.

However, in order to prevent leakage of vibration energy, it would be convenient to mechanically fix the crystal substrate or the like at the end of the substrate in the axial direction away from the vibration propagation direction.

From this point of view, the vibration propagation axis direction is generally often selected to be the Z' force direction and the supporting force direction to be the 4X axis direction.

The present invention has been described above using the case where a typical piezoelectric vibrator and filter are fixed at one point and cantilevered as an example, but the present invention is not necessarily limited to this, and can also be applied to irregularly shaped piezoelectric devices. It goes without saying that there may be multiple fixed points.

(Effects of the Invention) Since the present invention is constructed as described above, it can meet the demands for smaller and thinner piezoelectric devices, and improve the performance of the device, especially preventing the leakage of thickness vibration energy. It has a remarkable effect.

[Brief explanation of drawings]

Figures 1 (al and b) are a plan view and an A-A sectional view showing one embodiment of the present invention, and Figures 2 (a) and (b) are plane views showing other embodiments of the present invention, respectively. Figure and BB sectional view,
FIGS. 3(a) and 3(b) are cross-sectional views showing different examples of conventional piezoelectric device support structures. 1.17...Piezoelectric device, 7...
...Flat package, 9...
...Piezoelectric device fixing land, 2.
20 and 21... Electrode lead part, 1
3...Terminal pad for wire bonding,
15・・・・・・Piezoelectric device electrode lead part back support land.

Claims (3)

[Claims] (1) In a flat package in which a piezoelectric device is housed so that its main surface is held almost horizontally, a land for fixing the outer periphery of the piezoelectric device in a proper position inside the package and a wall of the package are provided. It is characterized by comprising an in-package terminal pad of a lead that passes through the piezoelectric device in an airtight manner and is electrically connected to the electrode lead portion of the piezoelectric device by wire bonding, and a piezoelectric device support land located on the back side of the electrode lead portion of the piezoelectric device. Structure of piezoelectric device package. (2) When the piezoelectric device is fixed to the land that fixes its outer periphery, the surface of the piezoelectric device supporting land has a minute gap between it and the back surface of the electrode lead portion of the piezoelectric device. A structure of a piezoelectric device package according to claim (1). (3) The piezoelectric device according to claim (1) or (2), wherein the land for fixing the outer peripheral edge of the piezoelectric device also serves as an electrical connection between the piezoelectric device electrode lead and the outside of the package. Package structure.