JP2002359523A - Piezoelectric oscillator and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric oscillator which realizes miniaturization, and aims at yield improvement and cost reduction. SOLUTION: In a piezoelectric oscillator, comprising a piezoelectric vibrator formed by housing a piezoelectric element plate in a case having a concave opening and a semiconductor component, a pattern for conduction is formed around the opening of the case having the concave opening, the pattern abuts an terminal of the semiconductor component to make electrical connection, and an airtightly sealed structure is formed as a lid of the case by the semiconductor component. Further, an oscillation circuit is incorporated only in what obtains satisfactory characteristic as a piezoelectric vibrator to configure a piezoelectric oscillator, thereby improving the yield, and still further, an oscillator is configured with only completed members, thereby reducing the cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used in the field of mobile communication such as wireless communication equipment and mobile phones, and in all clock signal sources such as GPS, computers, audio products, video decks, video cameras, home appliances and the like. The present invention relates to a structure of a piezoelectric oscillator that can reduce the size of an oscillator.

[0002]

2. Description of the Related Art As shown in an example of FIG. 6, a general oscillator is formed by arranging a printed pattern for an oscillation circuit on a laminated substrate, or a single-substrate substrate on which a multi-layer printing is performed and a conductive pattern is disposed on the same plane. An oscillator is formed by mounting a piezoelectric vibrator hermetically sealed in the same atmosphere as semiconductor components such as a capacitor, a resistor, and an integrated circuit that constitute an oscillation circuit.

[0003]

The piezoelectric vibrator constituting the oscillator has a temperature characteristic in which the frequency changes depending on the environmental temperature. As an example, in the case of an AT-cut crystal unit, the temperature at which the center frequency fluctuates least is set to around 25 ° C, and the temperature characteristics peculiar to the AT-cut crystal unit are such that the frequency fluctuation becomes large on the high temperature side and low temperature side. It is known to have.

[0004] As a recent trend, miniaturization, weight reduction, and price reduction have been rapidly developed mainly in the field of mobile communication such as wireless communication equipment and mobile phones. Therefore, in order to reduce the size and cost of a temperature-compensated oscillator that meets these demands, a semiconductor component and a hermetically sealed piezoelectric vibrator are mounted on the same plane of a laminated substrate. Therefore, a mounting area is required for the structure of the airtight container of the piezoelectric vibrator, which imposes restrictions on miniaturization. Also, if the piezoelectric vibrator alone is not hermetically sealed and integrated with an oscillation circuit component to make it a hermetically sealed container structure, especially in the case of a temperature-compensated piezoelectric oscillator, a temperature-compensated oscillator is formed while being a temperature-compensated oscillator. At present, it is difficult to maintain temperature compensation characteristics because the ambient temperature around the piezoelectric vibrator changes due to heat generated by the semiconductor components.

[0005] On the other hand, in order to reduce the cost, the cost of the semiconductor component is higher than the cost of the piezoelectric vibrator for the piezoelectric vibrator and the semiconductor component constituting the temperature compensated oscillator, and the failure of the temperature compensated oscillator is reduced. Since the factors are often caused by various characteristics of the piezoelectric vibrator, it is considered necessary to satisfy the desired characteristics of the piezoelectric vibrator before assembly and to reduce the consumption of semiconductor components, and further reduce the price. Above, it is also important to reduce the cost of the main components (container, piezoelectric vibrator, semiconductor component) constituting the piezoelectric oscillator.

[0006]

To solve these problems, the present invention relates to a piezoelectric oscillator comprising a piezoelectric vibrator in which a piezoelectric element plate is housed in a container having a concave opening, and a semiconductor component. A conductive pattern is formed around the opening of the container having the concave opening, and the pattern and the terminal of the semiconductor component come into contact with each other to make an electrical connection, and The problem is solved by a piezoelectric oscillator characterized in that a closed container structure is formed as a lid of the container.

In short, a container having a concave opening for accommodating a piezoelectric vibrator has a sealed structure using a semiconductor component as an oscillation circuit as a lid. Is a piezoelectric oscillator that uses a flip chip bonding, a wire bonding method, and an anisotropic conductive member, and has a structure in which a conductive pattern is formed on a contact surface between a container and a semiconductor component. . Therefore, the semiconductor parts constituting the oscillation circuit are exposed as lids of the piezoelectric vibrator, but the entire top surface of the lid of the piezoelectric vibrator is protected by a protective material in order to prevent damage or short circuit of the semiconductor parts due to external drag. Covering is also an effective means.

In order to consider the consumption of semiconductor components as one of the means for reducing costs, in the case of temperature-compensated oscillators, semiconductor components are mounted only on the piezoelectric vibrator itself having a desired frequency characteristic. By configuring the oscillator, it is possible to reduce the consumption of semiconductor components, which account for a large proportion of the total cost of the oscillator, and to reduce the number of main components that make up the piezoelectric oscillator by using the semiconductor components as a lid. Also, the cost as a piezoelectric oscillator can be reduced.

[0009] Further, as compared with the conventional oscillator, the height of the piezoelectric oscillator itself is reduced particularly in the height (thickness) direction by using a semiconductor component as a lid, so that the piezoelectric oscillator itself can be installed in a small mounting space. This is advantageous. The sealing step of the present invention is also characterized by curing the sealing member in a vacuum environment. At this time, the sealing member used in the sealing step is an insulating material such as resin, glass, and ceramic material, or an anisotropic conductive member.

[0010]

BACKGROUND ART In recent years, in the above-described piezoelectric oscillator, the external dimensions of a piezoelectric vibrator and a container for accommodating the piezoelectric vibrator have become extremely small. On the other hand, the semiconductor components, which are responsible for the temperature compensation circuit of the piezoelectric oscillator, perform temperature compensation for analog operation consisting of a cubic function generation circuit. And the area is approaching the container outline mentioned above,
This leads to a piezoelectric oscillator having the form described in the present invention.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In each drawing, the same reference numeral indicates the same object. FIG. 1 shows a sectional view of a piezoelectric oscillator 3 according to the present invention. In FIG. 1, a piezoelectric oscillator 3 has a piezoelectric vibrator 1 mounted inside a container 6, and a metal bump such as a conductive adhesive or solder is used as a sealing member 8 for the container 6 to which the piezoelectric vibrator 1 is electrically connected. A piezoelectric oscillator 3 having a sealed container structure formed by a semiconductor component 2 (used as a lid) joined by a material such as flip chip bonding, wire bonding, or an anisotropic conductive member.

Accordingly, although detailed wiring inside the container 6 is not shown, a conductive pattern 5 is formed on the joint surface between the semiconductor component 2 serving as a lid and the container 6 so as to be electrically conductive with the semiconductor component 2. Have been. A part of these conductive patterns 5 and the piezoelectric vibrator 1 housed in the container 6 are electrically connected, and furthermore, the piezoelectric vibrator 3 is electrically connected to the electrode 7 outside the container. Is used as a reference clock.

In short, as shown in FIG. 2 as viewed from the semiconductor component 2 (back side) side, a container 6 and the semiconductor component 2 constitute a hermetically sealed container in which the piezoelectric vibrator 1 is housed. The piezoelectric oscillator 3 is configured by adding a container 6 for accommodating the piezoelectric vibrator 1 and the semiconductor component 2 and electrically connecting the piezoelectric vibrator 1 to the piezoelectric vibrator 1. The thickness in the vertical direction can be reduced by using the semiconductor component 2 as a lid.

Accordingly, the piezoelectric oscillator 3 is composed of the container 6 hermetically sealed by the semiconductor component 2 and the piezoelectric vibrator 1 housed in the container. The piezoelectric oscillator 3 is obtained by placing the component 2 in a hermetically sealed structure, thereby forming an oscillation circuit and obtaining the piezoelectric oscillator 3.

In this case, the semiconductor component 2 is exposed as a lid, but it is also effective to cover the entire semiconductor component 2 with a protective material in order to prevent damage or short circuit of the semiconductor component 2 due to external drag. It is one of the means. In the present invention, the material of the container is a ceramic material or a resin material. In order to secure the connection and conduction between the semiconductor component 2 and the container, it is also effective to form the container joint surface by metal vapor deposition or metallization. There is.

On the other hand, since the airtight container is realized by the semiconductor component 2, the pressure in the airtight container is reduced due to the heat of the solder at the time of mounting on the circuit board in consideration of the step of mounting solder or the like on the mounting circuit board on the user side. Since it becomes difficult to maintain the airtight structure, the sealing step of the present invention can suppress the rise in the internal pressure of the container by curing the sealing member in a vacuum environment. At this time, the sealing member used in the sealing step is an insulating material such as resin, glass, and ceramic material, or an anisotropic conductive member.

In this embodiment, the container is hermetically sealed by the semiconductor component 2 as a lid of the container, and the shape of the connection electrode portion 7 with the mounting circuit board is shown in FIG. 3 or FIG. The embodiments shown are possible. In FIG. 3, the shape of the electrode portion 7 is one side (7
7) is a continuous convex shape, and FIG. 4 shows that the electrode portion 7 is an independent convex shape. Although not shown here, FIG. 3 and FIG. 4 may be combined to form a convex shape in which one side is continuous and the other is separated, or may be another combination. Absent.

In the embodiment of the present invention, an opening 4 is provided on the mounting circuit board side and the semiconductor component 2 as a lid is described. However, as shown in FIG. The position is opposite to that of the substrate side (FIG. 5A) or is not buried in the opening 4 of the semiconductor component 2 (FIG.
(B)) or a method using a wire bonding method (FIG. 5 (c)) for electrical connection of the semiconductor component 2 does not matter.

Further, in the present invention, in order to consider the consumption of the semiconductor component 2 as one of the means for reducing the cost, in the case of the temperature-compensated oscillator, only the piezoelectric vibrator 1 itself having the desired frequency characteristics has been obtained. By mounting the semiconductor component 2 and configuring the piezoelectric oscillator 3 as a lid, it is possible to suppress the consumption of the semiconductor component 2 which accounts for a large proportion of the total cost of the oscillator. Accordingly, the size of the conventional piezoelectric oscillator 3 can be reduced by suppressing the occupied volume in the thickness (height) direction, and the amount of the piezoelectric vibrator 1 and the semiconductor component 2 with respect to the entire piezoelectric oscillator 3 can be reduced. The cost can be reduced by improving the yield.

[0020]

According to the present invention, the semiconductor component and the piezoelectric vibrator constituting the oscillation circuit are mounted. By using the semiconductor component as a lid for making the piezoelectric vibrator a hermetically sealed structure, the piezoelectric oscillator itself is formed. By reducing the volume, the entire oscillator could be downsized.

[Brief description of the drawings] [Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view of the piezoelectric oscillator of the present invention as viewed from the back.

FIG. 3 is a perspective view showing the shape of an electrode portion of the present invention.

FIG. 4 is a perspective view showing another shape of an electrode portion of the present invention.

FIG. 5 is a sectional view showing another embodiment of the present invention.

FIG. 6 is a perspective view showing a conventional piezoelectric oscillator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric vibrator 2 Semiconductor component 3 Piezoelectric oscillator 4 Opening 5 Pattern 8 Sealing member

Claims (5)

[Claims] 1. A piezoelectric oscillator comprising a piezoelectric vibrator comprising a piezoelectric element stored in a container and a semiconductor component, wherein a conductive pattern is formed around an opening of the container, and the pattern and the semiconductor A piezoelectric oscillator in which a terminal portion of a component abuts to make an electrical connection, and the semiconductor component forms a closed container structure as a lid of the container. 2. The piezoelectric oscillator according to claim 1, wherein the container has a concave shape having an opening on a side on which the semiconductor component is mounted. 3. A method for manufacturing a piezoelectric oscillator comprising a piezoelectric vibrator in which a piezoelectric element is housed in a container and a semiconductor component, comprising: a conductive pattern around an opening of the container; and a terminal of the semiconductor component. The part is in contact with and makes electrical connection, and the sealing step for forming a closed container structure as a lid of the container by the semiconductor component is performed by curing the sealing member in a vacuum environment. A method for manufacturing a piezoelectric oscillator, characterized by sealing. 4. The method for manufacturing a piezoelectric oscillator according to claim 3, wherein the sealing member is made of a resin, glass, or ceramic material. 5. A piezoelectric oscillator and a method for manufacturing the same, wherein an anisotropic conductive member is used as a sealing member of the semiconductor component and the container according to claim 1.