JP2004194046A - Crystal resonator and crystal oscillator using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystal resonator for which vibration characteristics are excellent and a crystal oscillator accelerating miniaturization. <P>SOLUTION: In the crystal resonator composed of a crystal piece provided with a stress relaxation groove on the outer peripheral part of a vibration area, the groove is turned to first and second double grooves provided on the inner and outer sides and the vibration area is surrounded by the double grooves. Also, the crystal piece where an extraction electrode is extended on mutually opposing surfaces by an electrode through-hole provided on the outer periphery of the double groove from the excitation electrode of the vibration area, a semiconductor element having a crystal terminal connected to the extraction electrode on one main surface and an external terminal on the other main surface, for which an oscillation circuit is integrated, and a cover are provided. The crystal piece, the semiconductor element and the cover are provided with a gap and the outer periphery is sealed with a sealing member. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a crystal oscillator and a crystal oscillator using the same in an industrial technical field, and particularly relates to a crystal oscillator that promotes miniaturization.
[0002]
[Prior art]
BACKGROUND OF THE INVENTION Crystal oscillators are widely used in electronic equipment as frequency and time reference sources. In recent years, further miniaturization has been demanded and a response has been sought.
[0003]
(Example of Prior Art) FIGS. 3 (a) and 3 (b) are views for explaining a conventional example, wherein FIG. 3 (a) is a sectional view of a crystal oscillator and FIG. 3 (b) is a view of a crystal blank.
The crystal oscillator has a semiconductor substrate (IC chip) 3 and a crystal blank 2 housed in a mounting board 1 having a concave shape, covered with a cover 4 and hermetically sealed. The mounting board 1 has external terminals 5 for surface mounting. The semiconductor element 3 integrates an oscillation circuit, and is fixed to the bottom surface of the concave portion of the mounting substrate 1 by ultrasonic thermocompression using a bump 6. The crystal blank 2 has excitation electrodes 7 on both main surfaces, and a pair of extraction electrodes 8 extends on both sides of one end. Each extraction electrode 8 is formed by folding back on the opposite surface. Then, both ends of the one end are fixed to the step of the concave portion by the conductive adhesive 9.
[0004]
[Problems to be solved by the invention]
(Problems of the prior art) However, in the crystal oscillator having the above configuration, since the semiconductor element 3 and the crystal blank 2 are separately fixed in the mounting substrate 1, it is difficult to reduce the size in terms of structure. In addition, there is a problem that it is difficult to secure vibration characteristics because the crystal blank 2 is also small.
[0005]
(Object of the Invention) It is an object of the present invention to provide a crystal resonator having improved vibration characteristics and a crystal oscillator which promotes miniaturization.
[0006]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-28516
[Means for Solving the Problems]
According to the first aspect of the present invention, the stress relaxation grooves provided on the outer peripheral portion of the vibration region are first and second double grooves provided inside and outside, and the vibration region is surrounded by the double groove. Therefore, for example, even if the entire circumference is fixed (held), the stress generated in the vibration area is reduced because the groove is provided on the entire circumference, and the vibration characteristics are maintained.
[0008]
According to a second aspect of the present invention, a crystal piece in which extraction electrodes are extended from the excitation electrode in the vibration region to surfaces opposite to each other by electrode through holes provided in the outer periphery of the double groove, and a crystal terminal connected to the extraction electrode And a cover having an external circuit on one main surface, external terminals on the other main surface, and an integrated oscillation circuit. Then, a gap is provided between the crystal blank, the semiconductor element, and the cover, and the outer periphery is sealed with a sealing member.
[0009]
With this configuration, the outer periphery can be sealed because the electrode through-holes are provided in the crystal blank and the extraction electrodes are provided on both main surfaces. Since the cover and the semiconductor element electrically connected to both main surfaces of the crystal blank are joined, the height of the crystal oscillator can be reduced. Hereinafter, an embodiment of the present invention will be described.
[0010]
【Example】
FIG. 1 is a view for explaining an embodiment of the present invention. FIG. 1 (a) is an exploded view of a crystal oscillator, and FIG. 1 (b) is a front view thereof.
The crystal oscillator includes a crystal blank 2, a semiconductor element 3, and a cover 4. The crystal blank 2 has a substantially square shape, and has excitation electrodes 7 on both main surfaces with a central portion as a vibration region. The outer periphery of the vibration region has a double groove 10 of first and second grooves 10 (ab) provided inside and outside. The first groove 10a is formed in a hook shape at the four corners of the excitation electrode 7, and the second groove 10b is formed parallel to the four sides. In short, the double groove 10 is formed so as to surround the vibration region (the excitation electrode 7).
[0011]
From the excitation electrode 7, the extraction electrodes 8 extend to both sides of one end portion through the double groove 10, and further extend to opposite surfaces by electrode through holes 11. An annular electrode 12 for bonding is formed on the outer periphery of both main surfaces, and a ground electrode 14 having electrode through holes 11 on both sides of the other end.
[0012]
The semiconductor element 3 integrates an oscillation circuit, and one main surface side is used as a reference potential surface, here, a ground potential surface. As shown in Patent Document 1, a crystal terminal 13 is provided on one side of one main surface, a ground electrode 14 is provided on both sides of the other end, and external terminals such as a power supply, an output and a ground terminal (not shown) are provided on the other main surface. .
[0013]
The one main surface of the earth potential surface is electrically connected to the earth terminal. The ground terminal is connected to each external terminal, for example, a solder ball as the mounting terminal 5. An annular electrode 12 for bonding is formed on the outer periphery of one main surface. The cover 4 is made of a metal or a material having conductivity.
[0014]
In such a device, both sides of one end of the crystal piece 2 extending from the extraction electrode 8 and the crystal terminal 13 of the semiconductor element 3, the ground electrodes 14 of the two, and the two annular electrodes 12 provided on the outer periphery are used. And the crystal blank 2 and the cover 4 are positioned and laminated. However, a bonding metal 15 having a transition point temperature of 573 ° C. or lower, for example, a eutectic alloy made of AuSn is interposed between the contact surfaces of the crystal blank 2, the semiconductor element 3, and the cover 4. Then, the eutectic alloy is melted, joined, and sealed.
[0015]
With such a configuration, the electrode through-holes 11 are provided on both sides of one end of the crystal blank 2, the extraction electrode 8 extends on the same main surface, and the annular electrode 12 is formed on the outer periphery. Since the semiconductor element 3 is also used as the mounting substrate 1 and the crystal blank 2 and the cover 4 are laminated and sealed, the height dimension can be basically reduced. Note that a gap is formed between the joining metal 15 and the vibrating region by the thickness of the joining metal 15, and the vibration is maintained.
[0016]
Further, since the vibrating region of the crystal blank 2 is surrounded by the double groove 10, the stress from all directions is reduced. Therefore, even if the entire circumference of the crystal blank 2 is fixed to the semiconductor element 3 and the cover 4, the influence on the vibration region is reduced, and the vibration characteristics are improved. In this embodiment, since the cover 4 is made of metal and is electrically connected to the ground potential surface (one main surface side) of the semiconductor element 3, the cover 4 can be grounded, and a shielding effect can be obtained.
[0017]
[Other matters]
In the above embodiment, the crystal blank 2 and the semiconductor element 3 and the cover 4 are joined by providing the ring electrode 12 with a eutectic alloy, but the ring electrode may be removed and sealed with low melting point glass or resin. In this case, the cover 4 may be made of an insulating material such as ceramic. In short, the outer peripheries of the crystal blank 2, the semiconductor element 3, and the cover 4 may be sealed with a sealing member.
[0018]
Further, although the extraction electrode 8 extends to one side of the crystal blank 2, it may extend to a pair of diagonal portions. In this case, the ground electrode 14 is formed at another diagonal part. Then, in response to this, a crystal terminal 13 and a ground electrode are formed on one main surface of the semiconductor element 3.
[0019]
Further, although the crystal oscillator has been described as a crystal oscillator, the crystal blank 2 can also be used as a crystal oscillator by any holding means. For example, the outer periphery of the crystal blank 2 may be fixed to the bottom surface of the concave mounting board and sealed to form a crystal resonator. Further, although the vibration area is rectangular, it may be circular and may be formed arbitrarily.
[0020]
【The invention's effect】
According to the present invention, the grooves for stress relaxation provided on the outer peripheral portion of the vibration region are first and second double grooves provided on the inside and outside, and the vibration region is surrounded by the double groove. Can provide a crystal resonator that has been manufactured. A crystal piece having extraction electrodes extending from the excitation electrode in the vibration region to surfaces opposite to each other by electrode through holes provided on the outer periphery of the double groove, and a crystal terminal connected to the extraction electrode are provided on one main surface. A semiconductor element having an external terminal on the other main surface and an integrated oscillation circuit, and a cover, wherein a gap is provided between the crystal blank, the semiconductor element, and the cover, and the outer periphery is sealed with a sealing member. Therefore, it is possible to provide a crystal oscillator that maintains vibration characteristics and promotes miniaturization.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams illustrating an embodiment of the present invention. FIG. 1A is an exploded view of a crystal oscillator, and FIG. 1B is a front view thereof.
FIG. 2 is a plan view of a crystal unit explaining one embodiment of the present invention.
3A and 3B are diagrams illustrating a conventional example, wherein FIG. 3A is a cross-sectional view of a crystal resonator, and FIG. 3B is a plan view of a crystal blank.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 mounting board, 2 crystal pieces, 3 semiconductor elements, 4 covers, 5 mounting terminals, 6 bumps, 7 excitation electrodes, 8 extraction electrodes, 9 conductive adhesive, 10 double grooves, 11 through holes, 12 annular electrodes, 13 Crystal terminal, 14 ground electrode, 15 bonding metal.

Claims (2)

In a crystal resonator made of a crystal piece having a groove for stress relaxation provided on an outer peripheral portion of a vibration region, the groove is first and second double grooves provided inside and outside, and the vibration region is surrounded by the double groove. A crystal unit characterized by the following. A crystal piece having an extraction electrode extending from the excitation electrode in the vibration region to the opposite surface by an electrode through hole provided on the outer periphery of the double groove, and a crystal terminal connected to the extraction electrode on one main surface. A semiconductor element having an external terminal on the other main surface and an integrated oscillation circuit, and a cover, wherein a gap is provided between the crystal blank and the semiconductor element and the cover, and the outer periphery is sealed with a sealing member. Characterized crystal oscillator.

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