JP4685273B2 - Piezoelectric oscillator and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
Piezoelectric oscillators that can reduce the size of oscillators used in mobile communication fields such as wireless communication devices and mobile phones, and all clock signal sources including GPS, computers, audio products, video decks, video cameras, home appliances, etc. Related to the structure.
[0002]
[Prior art]
As shown in an example of FIG. 6, a general oscillator has an oscillation circuit on the same plane of a substrate on which a printed pattern for an oscillation circuit is arranged on a multilayer substrate, or a substrate on which a multi-layer printing is arranged on a single plate substrate. An oscillator is configured by mounting a hermetically sealed piezoelectric vibrator in the same atmosphere as semiconductor components such as capacitors, resistors, and integrated circuits.
[0003]
[Problems to be solved by the invention]
The piezoelectric vibrator constituting the oscillator has a temperature characteristic in which the frequency changes depending on the environmental temperature. As an example, the AT-cut crystal unit has the temperature characteristic of the AT-cut crystal unit, in which the temperature with the smallest fluctuation in the center frequency is set to around 25 ° C, and the frequency change increases at high and low temperatures. It is known to have.
[0004]
As a recent trend, miniaturization, weight reduction, and price reduction are rapidly developing mainly in the mobile communication field such as wireless communication devices and mobile phones. For this reason, in order to reduce the size and the price of a temperature compensated oscillator that meets these requirements, a structure in which a semiconductor component and a hermetically sealed piezoelectric vibrator are mounted on the same plane of a multilayer substrate is provided. Therefore, the mounting area is required for the airtight container structure of the piezoelectric vibrator, and there are restrictions on downsizing. Further, if only the piezoelectric vibrator is integrated with the oscillation circuit component without hermetically sealing to reduce the size of the hermetic container structure, particularly in the case of the temperature compensated piezoelectric oscillator, the temperature compensated oscillator is configured. At present, it is difficult to maintain the temperature compensation characteristic because the ambient temperature of the piezoelectric vibrator changes due to heat generation of the semiconductor component.
[0005]
On the other hand, regarding the realization of lower prices, the cost of semiconductor parts is higher than the cost of piezoelectric vibrators in the piezoelectric vibrators and semiconductor parts that make up a temperature compensated oscillator. Since it is often caused by various characteristics of the vibrator, it is considered necessary to satisfy the desired characteristics of the piezoelectric vibrator before assembly, and to suppress the consumption of the semiconductor parts. Cost reduction of main parts (containers, piezoelectric vibrators, semiconductor parts) constituting the piezoelectric oscillator is also important.
[0006]
[Means for solving the problems]
In order to solve these problems, the present invention provides a container whose outer shape is a substantially rectangular parallelepiped and has a concave opening recessed on the inner side on one surface thereof, and a piezoelectric vibrator housed in the opening. And a piezoelectric oscillator composed of a semiconductor component electrically connected to the piezoelectric vibrator, wherein the predetermined surface of the semiconductor component is formed larger than an opening area of the opening, and the semiconductor component is The predetermined one surface of the semiconductor component and the periphery of the opening are arranged so as to hermetically close the opening by bonding via a sealing member, and formed around the opening pattern for conduction and said semiconductor component of the terminal portion is a piezoelectric oscillator which is characterized that you have electrically connected, and the sealing member solves the problem by an anisotropic conductive member It is.
[0007]
In short, a semiconductor part that is an oscillation circuit is used as a lid, and a container having a concave opening that houses a piezoelectric vibrator is used as a sealed structure. For electrical connection between the piezoelectric vibrator and the semiconductor part , The piezoelectric oscillator 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 surface on which a semiconductor component of the container is disposed . Therefore, the semiconductor components that make up the oscillation circuit are exposed as a lid of the piezoelectric vibrator, but the entire upper surface of the lid of the piezoelectric vibrator is protected with a protective material in order to prevent damage to the semiconductor components and short circuit due to external drag. Covering is also an effective means.
[0010]
【background】
Recently, in the above-described piezoelectric oscillator, the outer dimensions of the piezoelectric vibrator and the container for storing the piezoelectric vibrator have become very small. On the other hand, the semiconductor component responsible for the temperature compensation circuit of the piezoelectric oscillator performs temperature compensation for analog operation consisting of a cubic function generation circuit. Therefore, when viewed from the design rules and circuit configuration of the semiconductor component, the external dimensions of the semiconductor component itself From the present situation where the area is approaching the aforementioned outer shape of the container, the piezoelectric oscillator having the form described in the present invention is reached.
[0011]
[Embodiments of the Invention]
Embodiments of the present invention will be described below with reference to the accompanying drawings. In each figure, the same numerals indicate the same objects. FIG. 1 shows a cross-sectional view of a piezoelectric oscillator 3 of the present invention. In FIG. 1, a piezoelectric oscillator 3 has a piezoelectric vibrator 1 mounted inside a container 6, and an insulating material such as resin, glass, ceramic material or an anisotropic conductive member is attached to the container 6 to which the piezoelectric vibrator 1 is electrically connected. This is a piezoelectric oscillator 3 having a sealed container structure with a semiconductor component 2 (with a lid) joined by a sealing member 8 .
[0012]
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 connected to the semiconductor component 2. . A part of the conductive pattern 5 and the piezoelectric vibrator 1 accommodated in the container 6 are electrically connected, and further, the piezoelectric oscillator 3 is electrically connected to the electrode portion 7 outside the container. The frequency output is used as a reference clock.
[0013]
In short, as shown in the figure seen from the semiconductor component 2 (back surface) side shown in FIG. 2, the container 6 and the semiconductor component 2 constitute a sealed container, and the so-called piezoelectric oscillator 3 in which the piezoelectric vibrator 1 is housed. The piezoelectric oscillator 3 is configured by adding the container 6 for housing the piezoelectric vibrator 1 and the semiconductor component 2 and electrically connecting the piezoelectric vibrator 1 to the height direction of the piezoelectric oscillator 3. The thickness can be reduced by using the semiconductor component 2 as a lid.
[0014]
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, and the semiconductor component 2 is mounted as a lid with the piezoelectric vibrator 1 mounted inside the container. An oscillating circuit is formed to obtain the piezoelectric oscillator 3 by covering the sealing structure to obtain the piezoelectric oscillator 3.
[0015]
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 the semiconductor component 2 from being damaged or short-circuited due to external drag or the like. It becomes. In the present invention, the material of the container is a ceramic material or a resin material, and it is also effective to form the container joint surface by metal vapor deposition or metallization in order to ensure the joining and conduction between the semiconductor component 2 and the container. There is.
[0016]
On the other hand, since the airtight container is realized by the semiconductor component 2, when the mounting process of solder or the like on the mounting circuit board on the user side is taken into consideration, the pressure in the airtight container increases due to the solder heat when mounting on the circuit board. Since it becomes difficult to maintain the structure, an increase in the internal pressure of the container can be suppressed by curing the sealing member in a vacuum environment in the sealing process of the present invention. At this time, the sealing member used in the sealing step is an insulating material such as resin, glass, or ceramic material, or an anisotropic conductive member.
[0017]
In this embodiment, the container is hermetically sealed by the semiconductor component 2 as the container lid, and the shape of the connection electrode portion 7 with the mounted circuit board is the embodiment shown in FIG. 3 or FIG. Can be considered. In FIG. 3, the shape of the electrode portion 7 is a convex shape in which the opposite sides (77) of the container are continuous, and FIG. 4 shows that the electrode portion 7 has 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 any other combination. Absent.
[0018]
In the embodiment of the present invention, the description has been made in the form in which the opening 4 is provided on the mounting circuit board side and the semiconductor component 2 that is the lid is arranged. However, as shown in FIG. Is the opposite positional relationship (FIG. 5A), is not buried in the opening 4 of the semiconductor component 2 (FIG. 5B), or is a wire bonding method for electrical connection of the semiconductor component 2. Even what uses (FIG.5 (c)) does not ask the form.
[0019]
Further, in the present invention, in order to consider the consumption of the semiconductor component 2 as one of the cost reduction means, in the temperature compensated oscillator, the semiconductor component 2 is only the one that the piezoelectric vibrator 1 itself has obtained a desired frequency characteristic. And the piezoelectric oscillator 3 is configured as a lid, it is possible to suppress the consumption of the semiconductor component 2 that occupies a large proportion of the total cost of the oscillator. Accordingly, the conventional piezoelectric oscillator 3 can be reduced in size by suppressing the volume occupied in the thickness (height) direction, and the amount of the piezoelectric vibrator 1 and the semiconductor component 2 input to the entire piezoelectric oscillator 3 can be obtained. Cost reduction can also be realized by improving the yield.
[0020]
【The invention's effect】
The semiconductor component and the piezoelectric vibrator constituting the oscillation circuit are mounted according to the present invention, but the volume of the piezoelectric oscillator itself is reduced by using the semiconductor component as a lid for making the piezoelectric vibrator into a sealed structure. As a result, the entire oscillator could be reduced in size.
[Brief description of the drawings]
FIG. 1 is a cross-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 side.
FIG. 3 is a perspective view showing an electrode part shape of the present invention.
FIG. 4 is a perspective view showing another electrode part shape of the present invention.
FIG. 5 is a cross-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 part 5 Pattern 8 Sealing member

Claims (2)

The outer shape is a substantially rectangular parallelepiped, and a container provided with a concave opening recessed on the inner side on one surface thereof;
A piezoelectric vibrator housed in the opening;
In a piezoelectric oscillator composed of a semiconductor component electrically connected to the piezoelectric vibrator,
The predetermined surface of the semiconductor component is formed larger than the opening area of the opening,
The semiconductor component is arranged so that the predetermined surface of the semiconductor component and the periphery of the opening are joined together via a sealing member so as to hermetically close the opening, and the periphery of the opening piezoelectric oscillator and the pattern and the semiconductor component terminal portions for formed conduction to is characterized that you have electrically connected. The piezoelectric oscillator according to claim 1, wherein the sealing member is an anisotropic conductive member .

Images