JP3928520B2 - Piezoelectric oscillator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric oscillator in which a vibration element and an oscillation circuit element are mounted in a composite package composed of a metal container and a resin container, and particularly relates to a package structure.
[0002]
[Prior art]
Surface mount type temperature compensated crystal oscillators are used in various electrical devices such as mobile communication terminals. In recent years, as with electronic components such as diodes and capacitors, there has been a demand for improved productivity as well as reduction in size and thickness.
[0003]
As means for solving this, there is one described in JP-A-2001-7647. 2A is a perspective view of a conventional surface mount type temperature compensated crystal oscillator, FIG. 2B is an assembled view, and FIG. 2C is a YY line in FIG. 2B. FIG. 101 is a lid formed of a metal plate made of iron-nickel-cobalt alloy (hereinafter referred to as Kovar) or iron-nickel alloy, 102 is a crystal piece having a metal vapor-deposited electrode, and 103 is a laminated ceramic for housing the crystal piece. Reference numeral 104 denotes an IC chip having a temperature compensation circuit, and reference numeral 105 denotes a container made of a multilayer ceramic for accommodating the IC chip.
[0004]
A detailed configuration will be described below. First, the crystal piece 102 is stored in the multilayer ceramic container 103 for storing crystal pieces. At this time, the electrode of the crystal piece 102 and the storage electrode pad of the ceramic container 103 are electrically bonded using a silver paste or the like. Further, the lid body 101 is hermetically sealed on the upper surface portion of the 103 containing the crystal piece 102.
[0005]
Next, the IC chip 104 having the temperature compensation circuit is accommodated by flip chip bonding on the wiring lead provided in the multilayer ceramic container 105 for accommodating the IC chip. Temperature compensation is achieved by electrically and mechanically bonding the lower electrode of the ceramic container 103 containing the crystal piece 102 and hermetically sealed by the lid 101 and the upper electrode of the ceramic container 105 containing the IC chip 104. A crystal oscillator with a type IC is formed. By adopting this structure, each storage component can be inspected separately, and productivity can be improved.
[0006]
[Problems to be solved by the invention]
According to the package structure of the conventional crystal oscillator as described above, since the ceramic is used for the container for storing each component, the plate thickness is 0.2 mm or less considering the maintenance of the container strength against the external stress. It is difficult to achieve this, and there is a limit in reducing the size and thickness. Further, even in the case of a package constituted only by a resin container instead of a ceramic container, there is a limit in achieving a reduction in size and thickness in consideration of maintaining the container strength against external stress.
[0007]
That is, when a container made of ceramic or resin is reduced in size and thickness, a new problem arises in that the container strength against external stress decreases. For this reason, there is a problem that there is a limit to reducing the size and thickness of the entire package.
[0008]
Accordingly, an object of the present invention is to provide a piezoelectric oscillator that can be made smaller and thinner than a ceramic container or a package made only of a resin container and has a structure that is strong against external stress.
[0009]
[Means for Solving the Problems]
The piezoelectric oscillator according to the present invention includes a vibration unit in which a vibration element is housed in a first container that has an upper surface open and can be sealed with a lid, a second container that is joined to the vibration unit, and a second container It consists of an oscillation circuit element housed inside and an integrated element having a temperature compensation function. The first container is a metal container and is hermetically sealed with a metal lid, and the second container is made of a resin. A lead electrode is embedded in the container, and the first container and the second container are electrically connected by the connection electrode. Further, a through hole is formed in the bottom surface of the first container, and the connection terminal is hermetically penetrated using a joining member. Also, a support step is formed on the inner wall side surface of the second container, and the first container is supported by this support step. Moreover, it joins so that a 2nd container may contain a 1st container.
[0010]
According to the present invention, by using a combination of a metal container and a resin container, it can be made smaller and thinner than a ceramic container or a package made only of a resin container. Furthermore, by forming a support step that supports the bottom of the metal container on the side of the inner wall of the resin container, the bottom of the metal container contacts or collides with the IC chip due to external stress from the vertical direction, damaging the IC chip. Since the metal container has a structure that supports and reinforces the side surface of the resin container from the inner wall side of the resin container by joining the metal container so that the resin container encloses the resin container. Even if the plate thickness of the container is reduced, the container strength in the horizontal direction can be maintained.
[0011]
Therefore, by using the composite package including the metal container and the resin container, the piezoelectric oscillator can be reduced in size and thickness, and can have a structure strong against external stress from the vertical direction and the horizontal direction.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. FIG. 1A is a perspective view showing a temperature compensated crystal oscillator using a composite package according to the present invention, and FIG. 1B is a temperature compensated crystal oscillator having the configuration shown in FIG. The completed figure which assembled was shown.
[0013]
1 (a) and 1 (b), 1 is a metal lid formed of a plate made of Kovar or iron-nickel alloy or the like, 2 is processed according to each frequency, and the surface is an excitation electrode. 3 is formed on the surface of the crystal piece by an excitation electrode formed by a metal vapor deposition film, and 4 is formed by press-molding a plate material made of Kovar or iron-nickel alloy. The metal container 5 formed in a box shape is hermetically sealed through a glass material in a through hole formed in the bottom of the metal container, and a lead terminal for electrically connecting the crystal piece to the outside, 6 is an IC chip composed of an integrated element having an oscillation circuit element and a temperature compensation circuit, 7 is formed of a resin and a metal lead frame, and its shape is formed in a box shape with an open top surface and is supported on the side surface of the inner wall A resin container for storing an IC chip having a portion 11, 8 is a metal lead frame processed in accordance with the pin arrangement of the IC chip 6, 9 is a wiring lead to the IC chip provided in the resin container, and a crystal piece It is an electrode used for electrical connection.
[0014]
The structure of the crystal oscillator using this composite package is as follows. The excitation electrode 3 of the crystal piece 2 is bonded to the lead terminal 5 provided in the metal container 4 by using a conductive adhesive such as silver paste, and the metal lid 1 is sealed on the upper surface by Au / Sn sealing or the like. Is hermetically sealed, so that the crystal piece 2 is housed in the metal container 4 in an airtight manner.
[0015]
Next, the IC chip 6 is flip-chip bonded on the lead frame 8 provided in the molded resin container 7 and processed in accordance with the pin arrangement of the IC chip 6, and the IC chip is placed in the resin container 7. 6 is stored. After the crystal piece 2 is accommodated in the metal container 4 and the IC chip 6 is accommodated in the resin container 7, the lead terminal 5 provided in the metal container 4 and the electrode 9 provided in the resin container 7 are made of conductive paste or the like. The crystal piece 2 and the IC chip as shown in FIG. 1B are assembled by electrically assembling them, and assembling so that the metal container 4 fits in the resin container 7 and fixing the space with an adhesive or the like. 6 is housed in each container to form a temperature compensated crystal oscillator.
[0016]
As described above, the crystal piece 2 and the IC chip 6 are stored in the metal container 4 and the resin container 7 without using the ceramic container, which is different from the conventional example. That is, by not using the ceramic container, the entire package can be made smaller and thinner without being restricted by the ceramic plate thickness.
[0017]
Moreover, since the metal container 4 has a structure in which the metal container 4 supports and reinforces the side surface of the resin container 7 from the inner wall side of the resin container 7 by forming a package in which the metal container 4 and the resin container 7 are combined. The strength of the package can be improved as compared with the package.
[0018]
At this time, the plate thickness of the resin container 7 can be reduced to about 0.1 mm because the metal lead frame 8 is formed inside.
[0019]
1C is a cross-sectional view taken along line XX in FIG. 1B, and FIG. 1D is a bottom surface portion of a package in which the metal container 4 and the resin container 7 are combined. 1 (c) and 1 (d), 10 is a flange provided on the outer periphery of the metal container, 11 is a support step for supporting the metal container 4 formed on the side of the inner wall of the resin container 7, Reference numeral 12 denotes an external electrode formed by bending the lead frame 8 on which each pin of the IC chip 6 is mounted on the outer bottom surface of the resin container 7 by bending.
[0020]
As shown in FIG. 1C, the metal container 4 housing the crystal piece 2 and the resin container 7 housing the IC chip 6 are assembled by bonding with an adhesive or the like. Further, the lead piece 5 provided in the metal container 4 and the electrode 9 provided in the resin container 7 are bonded using a conductive paste such as silver paste, thereby electrically connecting the crystal piece 2 and the IC chip 6. Connected to. Further, the IC chip 6 is flip-chip bonded by using bumps or the like on the lead frame 8 provided in the IC chip and processed according to the pin arrangement for VC, GND, program writing or the like. The position where the IC chip 6 is bonded is a position that does not reach the protruding range of the lead terminal 5 of the metal container 4 housing the crystal piece 2.
[0021]
Further, as shown in FIG. 1D, the lead frame 8 is routed from the pin mounting portion to the external electrode 12 on the bottom surface, thereby enabling external contact with the IC chip 6.
[0022]
Thus, by joining so that the metal container 4 is included in the resin container 7, the package can be further reduced in height, and the metal container 4 can be moved from the inner wall side of the resin container 7 to the side surface of the resin container 7. Therefore, even when the resin container 7 is thin, the container strength against external stress can be maintained. Further, by providing the support step portion 11 that supports the metal container 4 on the inner wall side surface of the resin container 7, the bottom portion of the metal container 4 contacts or collides with the IC chip 6 due to external stress, and the IC chip 6 is damaged. Can be prevented. Furthermore, the height can be reduced by removing the IC chip 6 from the range where the lead terminals 5 of the metal container 4 are provided and performing flip chip bonding.
[0023]
In the above description, the arrangement of the lead terminals 5 provided on the metal container 4 is shown as two arranged on one side as shown in FIG. Is possible.
[0024]
【The invention's effect】
According to the present invention, by using a combination of a metal container and a resin container, the size and thickness can be reduced as compared with a ceramic container or a package made of only a resin container. Further, by forming a support step for supporting the metal container on the inner wall side surface of the resin container, the bottom of the metal container contacts or collides with the IC chip due to external stress from the vertical direction, and the IC chip is damaged. Can be prevented. Furthermore, by joining the metal container so that the resin container is contained, the metal container has a structure that supports and reinforces the side surface of the resin container from the inner wall side of the resin container. The container strength from the horizontal direction can be maintained. Therefore, by using this composite package, the piezoelectric oscillator can be reduced in size and thickness, and can have a structure strong against external stress from the vertical direction and the horizontal direction.
[Brief description of the drawings]
FIG. 1 is a configuration diagram, assembly diagram, sectional view, and bottom view showing a crystal oscillator using a composite package. FIG. 2 is a configuration diagram, assembly diagram, and sectional view of a conventional crystal oscillator using a multilayer ceramic. Explanation】
DESCRIPTION OF SYMBOLS 1 Metal cover body 2 Crystal piece 3 Excitation electrode 4 Metal container 5 Lead terminal 6 IC chip 7 Resin container 8 Lead frame 9 Electrode 10 Flange part 11 Supporting step part 12 External electrode 101 Cover body 102 Crystal piece 103 Crystal piece accommodation ceramic Container 104 IC chip 105 Ceramic container for storing IC chip

Claims (4)

A vibration unit having a connection terminal electrically connected to an excitation electrode of the vibration element, the vibration element being housed in a first container whose upper surface is open and whose upper surface can be sealed by a lid, and the vibration unit In the piezoelectric oscillator comprising a second container having an upper surface opened to be bonded to an oscillation circuit element and an oscillation circuit element housed in the second container, the first container is a metal container, It is hermetically sealed by a lid, and the second container is made of a resin-made container with a lead electrode embedded therein, and the first container and the second container are electrically connected by a connection electrode. A characteristic piezoelectric oscillator. The piezoelectric oscillator according to claim 1, wherein a through hole is formed in the bottom surface of the first container, and the connection terminal is hermetically penetrated using a joining member. 3. The piezoelectric oscillator according to claim 1, wherein a support step is formed on the inner wall side surface of the second container, and the first container is supported by the support step. 4. The piezoelectric oscillator according to claim 3, wherein the first container is joined so that the second container is included.

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