JP2001177347A - Crystal oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystal oscillator, capable of facilitating facedown bondining and high in productivity by eliminating wastage of IC chips. SOLUTION: In this crystal oscillator, where the IC chip and a crystal chip are contained in a ceramic package with a recessed part, a step difference is provided on the sidewall of the recessed part of the ceramic package and a sealing cover is joined with the step difference to form 1st and 2nd spaces, and the crystal chip is contained in the lower 1st space and the IC chip is contained in the upper 2nd space.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field of use of a crystal oscillator for surface mounting, and more particularly to a crystal oscillator with improved productivity.

[0002]

2. Description of the Related Art Crystal oscillators are widely used as various frequency and time reference sources in various electronic devices including communication devices. In recent years, with an increase in demand, a crystal oscillator with improved productivity has been desired.

FIG. 3 is a cross-sectional view of a crystal oscillator illustrating a conventional example. The crystal oscillator is configured by housing a crystal blank 2, an IC chip 3, and a capacitor 4 in a ceramic container 1. The ceramic container 1 has a concave portion on one surface side and a step on a wall portion. Then, the IC chip 3 is fixed to the bottom of the concave portion by face-down bonding, and both ends of the crystal blank 2 are fixed to the stepped portion by the conductive adhesive 5. The cover 6 is joined to the opening surface of the concave portion by, for example, seam welding, and hermetically seals the crystal blank 2.

The IC chip 3 integrates various elements such as an amplifier constituting an oscillation circuit. Extraction electrodes extend from the excitation electrode to both sides of one end of the crystal piece 2 (not shown). Reference numeral 7 denotes a metal ring for seam welding, and reference numeral 8 denotes a bump for face-down bonding. Alternatively, as shown in FIG. 4, concave portions are provided on both sides, and the crystal blank 2 is accommodated in the concave portion on one main surface, and the IC chip 3 is accommodated in the concave portion on the other main surface. Reference numeral 9 denotes a resin material for protecting the IC chip.

[0005]

[Problems to be Solved by the Invention]
However, in the crystal oscillator having the above configuration, for example, in the former case, the crystal blank 2 is held on the step portion and sealed after the mounting of the IC chip 3. Therefore, when a defect occurs in the crystal blank 2 (crystal oscillator) due to the curing shrinkage of the conductive adhesive 5,
The expensive IC chip 3 itself is also discarded, causing waste.

In the latter case, the IC chip 3 can be mounted after confirming the characteristics of the quartz oscillator alone, so that the IC chip 3 is not wasted. However, since the bottom wall 10 floats in the air, when the IC chip 3 is subjected to face-down bonding by ultrasonic thermocompression bonding or thermocompression bonding, the bottom wall 10 is bent by the pressing force, making the operation difficult. In any case, the work of mounting the crystal blank 2 and the IC chip 3 is a linear work in terms of time, and has a problem of low productivity.

(Object of the Invention) It is an object of the present invention to provide a crystal oscillator which facilitates face-down bonding by eliminating waste of an IC chip and has high productivity.

[0008]

According to the present invention, a sealing cover 11 is provided at a step on the side wall of a concave portion of a ceramic container 1 to join a sealing cover 11, thereby forming first and second spaces above and below.
The basic solution is to accommodate the crystal blank 2 in the lower first space and the IC chip 3 in the upper second space.

[0009]

According to the present invention, since the crystal blank 2 is accommodated in the first space, the characteristics of the single crystal resonator can be confirmed and the IC chip 3 can be checked.
Pass / Fail can be determined before mounting. Also, for example, by mounting the IC chip 3 on the sealing cover 11, the mounting work of the crystal blank 2 and the IC chip 3 can be performed in parallel. Hereinafter, embodiments of the present invention will be described.

[0010]

FIG. 1 is a sectional view of a crystal oscillator for explaining a first embodiment of the present invention. The same parts as those in the prior art are denoted by the same reference numerals, and description thereof will be simplified or omitted.
As described above, the crystal oscillator includes a crystal container 2 and an IC chip 3 housed in a ceramic container 1. In this example, both ends of one end of the crystal blank 2 are fixedly held to a crystal terminal provided on the bottom surface of the concave portion of the ceramic container 1. Then, the sealing cover 11 is joined to the step provided on the side wall of the concave portion by, for example, low melting point glass or resin (not shown). In the sealing cover 11,
Circuit elements including the IC chip 3 are mounted in advance. And
A resin is filled on the sealing cover 11.

The crystal terminal connected to the extraction electrode of the crystal piece 2 extends through the step surface of the side wall by a through hole, and is connected to the circuit pattern terminal formed on the sealing cover 11 by a conductive adhesive or the like (not shown). Illustrated). Further, the circuit pattern extends to the mounting electrodes on the bottom and side surfaces (not shown).

With such a configuration, the conductive adhesive 5
After holding the crystal blank 2, the characteristics of the crystal resonator can be confirmed and defective products can be eliminated. Therefore, the expensive IC chip 3
Waste can be eliminated. In addition, the IC chip 3 can be mounted on the sealing cover 11 while holding the crystal blank 2. Therefore, the mounting work of the crystal blank 2 and the IC chip 3 can be processed in parallel, so that the productivity can be improved. Since the IC chip 3 is fixed by face-down bonding using the sealing cover 11 as a flat plate, the operation is facilitated without bending the sealing cover 11.

[0013]

FIG. 2 is a sectional view of a crystal oscillator for explaining a second embodiment of the present invention. The description of the same parts as those in the first embodiment is omitted or simplified. In the first embodiment, the circuit element including the IC chip 3 is mounted on the sealing cover 11,
In this example, it is mounted on a circuit board 12 separate from the sealing cover 11. After joining the sealing cover 11 to the step of the ceramic container 1, the sealing cover 11 is joined to the opening surface by, for example, a resin. In addition, the crystal terminal is formed by the through hole in the side wall.
It is connected to a pattern terminal of the circuit board 12 (not shown).

With such a configuration, the quality of the crystal unit is checked and non-defective products are selected as described above.
Waste of the C chip 3 can be eliminated. Further, defects of the crystal unit due to sealing can be eliminated, and waste can be eliminated. Since the mounting work of the crystal blank 2 and the IC chip 3 can be processed in parallel, the productivity can be improved. Further, since the IC chip 3 is fixed to the circuit board 12 having a flat plate by face-down bonding, the operation is facilitated as described above.

[0015]

[Other Matters] In the present invention, the above two embodiments have been described.
The point is that the first and second spaces are formed vertically by the sealing cover 11, the crystal blank 2 is mounted in the lower first space, and the IC chip 3 is mounted in the upper second space. Should be fine. For example, the crystal piece 2 may be extended at both ends by extending the extraction electrodes to hold both ends. Although the circuit elements are the IC chip 3 and the capacitor 4, the IC chip 3 alone or other elements may be mounted.

[0016]

According to the present invention, the first and second spaces are formed on the upper and lower sides of the ceramic container, and the sealing cover is joined to the recessed side wall of the ceramic container. Since the crystal chip is accommodated in the upper second space portion and the IC chip is accommodated, it is possible to eliminate waste of the IC chip, facilitate face-down bonding, and provide a crystal oscillator with high productivity.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a crystal oscillator illustrating one embodiment of the present invention.

FIG. 2 is a sectional view of a crystal oscillator illustrating another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a crystal oscillator illustrating a conventional example.

FIG. 4 is a cross-sectional view of a crystal oscillator illustrating a conventional example.

[Explanation of symbols]

1 ceramic container, 2 crystal pieces, 3 IC chips, 4
Capacitor, 5 conductive adhesive, 6 cover, 7 metal ring, 8 bump, 9 resin material, 10 bottom wall, 11
Sealing cover.

Claims (1)

[Claims] 1. A crystal oscillator in which an IC chip and a crystal piece are accommodated in a ceramic container having a concave portion, a step is provided on a side wall of the concave portion of the ceramic container, and a sealing cover is joined to the step to form an upper and lower part. Forming a first and second space,
A crystal oscillator including a crystal blank in the lower first space and an IC chip in the upper second space.