JPS59191916A - Crystal oscillator and its production - Google Patents

Abstract

PURPOSE:To increase the CI value of a crystal oscillator and to prevent the frequency variation of the oscillator due to a secular change, by using an alloy layer which is formed by a diffusing means between at least >=2 types of metallic thin films laminated on a crystal plate to form an electrode of the crystal oscillator. CONSTITUTION:A double structure of a chrome thin film (a) and a gold thin film (b) is secured for electrodes 3-10 of each crystal oscillation arm and pad parts X and Y respectively by forming a chrome thin film to a crystal plate on the face to be used as an electrode by a vapor deposition process, a sputtering process, etc. and then forming a gold thin film in the same way. Then a diffusion function is produced between metals with high-temperature processing under vacuum. Thus both metals of films (a) and (b) are alloyed. This alloyed metal has a lower level of hardness than the chrome itself and has a higher hardness than the gold itself. This prevents the increment of CI value as well as the increment of the frequency of a crystal oscillator owing to a secular change.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a crystal resonator, and in particular, in order to improve the aging characteristics of the crystal resonator and the characteristics of the crystal resonator at CI value, Concerning an improved crystal oscillator.

The present invention also relates to a method for manufacturing a crystal resonator according to the present invention, and in particular, in order to facilitate the manufacture of the crystal resonator,
The present invention relates to a method of manufacturing a crystal resonator that facilitates the formation of electrodes.

BACKGROUND OF THE INVENTION Crystal oscillators commonly used in communication equipment, electronic watches, measuring instruments, etc. are the heart of the device, and are required to have high stability and reliability.

By the way, conventionally, the electrodes of crystal resonators are made of gold.

Metals such as silver and aluminum were formed on quartz plates using vapor deposition technology. However, with this electrode structure,
Since the adhesion force of the electrodes to the crystal plate is weak, in order to strengthen the adhesion of the electrodes to the crystal plate and make the crystal resonator a durable structure, chromium, which firmly adheres to the crystal plate, is first vapor-deposited and formed. Furthermore, the electrodes of the crystal resonator were formed by vapor-depositing gold, silver, aluminum, etc. on that one piece.

In addition, the upper pole of the crystal resonator is
1°1 (It is electrically connected to the terminal, but for this connection, the above gold, silver, etc. formed on the top surface of the electrode is fixed with the terminal or the lead wire from the terminal with solder etc. .

Problems with the Prior Art However, in the conventional crystal resonator described above, [1] Chromium is a harder metal than gold, etc., and its stress hinders the vibration of the crystal resonator. CI(
This not only increases the crystal impedance value, but also increases the change in the frequency of the crystal oscillator due to aging.

[2] Since gold, silver, and aluminum formed on the upper surface of the electrode are soft metals among metals, scratches are likely to occur on the surface of the metals during the manufacturing process of the crystal resonator. [3] When gold and silver are used alone, they tend to cause so-called sink marks over time, and these whiskers grow afterwards, and in the worst case, they extend from one electrode to the other.
This will result in a short circuit. Furthermore, [4] the gold, silver, and aluminum formed on the upper surface of the electrode cause a so-called eating phenomenon due to the solder, etc., which is the fixing material to the terminal, etc., and this causes the fixation of the fixed part of the crystal resonator and the terminal. Not only does the adhesion force decrease and the impact resistance characteristics deteriorate, but also unfavorable phenomena occur for the crystal resonator's mechanical characteristics.

Purpose of the Invention Therefore, the purpose of the present invention is to prevent an increase in the CI value in a crystal resonator, a change in the frequency of the crystal resonator due to aging, and to prevent scratches, gold, silver, etc. on the electrode surface during the manufacturing process of the crystal resonator. It is an object of the present invention to provide a crystal resonator and a method for manufacturing the same, which prevent so-called whiskers and the phenomenon of being eaten away by solder, which is a fixing material between terminals, etc. and electrodes.

Summary of the Invention The present invention provides a crystal resonator having electrodes on a crystal plate, and the electrodes are formed on a first metal made of chromium or the like formed on the crystal plate, and at least on the first metal. A second metal such as gold or the like is diffused to form an alloy.

Further, in the present invention, in order to form the above-mentioned electrode, a first metal that is diffused into other metals is formed on a quartz plate using a vapor deposition technique, and at least the first metal is formed on the first metal. This metal and a second metal that causes a diffusion effect are layered using vapor deposition technology or the like, and the first, second or more metals are diffused by vacuum high temperature treatment or the like to form an alloy.

Embodiment FIGS. 1, 2, and 3 are diagrams showing an embodiment of the present invention in which the present invention is implemented in a tuning fork crystal resonator, which is one type of crystal resonator.

FIG. 1 is a perspective view of a tuning fork-shaped crystal resonator according to the present invention, and FIG.
Figures 1 and 3 are cross-sectional views of the vibrating arm portion, and Figure 1 and S2
In Fig. 3, 1 and 2 are parts of a tuning fork-shaped crystal plate,
This is a vibrating arm extending in parallel from the base A. Excitation electrodes 3 and 4 are provided on the main surface of the vibrating arm 1 (hereinafter referred to as W main surface electrode J), and these are electrically connected to a pad section X provided on the base A. Furthermore, excitation electrodes 5 and 6 are provided on both sides of the vibrating arm 1 (hereinafter referred to as "side electrodes").
That's what it means. ), they are pad portion Y provided on base A
It is electrically connected to. Excitation electrodes 7 and 8 are provided on the main surface of the vibrating arm 2 (hereinafter referred to as 1 main surface electrode J), and are electrically connected to the pad portion Y.

Furthermore, excitation electrodes 9 and 10 are provided on both sides of the vibrating arm 2, respectively.
are provided (hereinafter referred to as "side electrodes j"), and are electrically connected to the band section The pad portions X and Y have the same name as the terminals of a tuning fork crystal resonator provided in a holder that holds a tuning fork crystal resonator l (not shown).

The electrodes 3, 4, 5, 6, 7, 8, 9° 10 and pad portions X and Y of each vibrating arm have a two-layer structure of a chromium thin film a and a gold thin film. To form these metal thin films a and b, first, a heptad chromium film is formed by vapor deposition or sputtering on the surface of the quartz plate that will become the electrode, and then gold is vapor-deposited or sputtered on the chromium thin film. It may be formed by a method such as sputtering. Here, the gold thin film may be a silver thin film or an aluminum thin film.

Then, the tuning fork-shaped crystal resonator thus formed is subjected to vacuum high temperature treatment (for example, 3506C) in a vacuum high temperature chamber.
Then, a diffusion effect occurs between each ROM and the metals of gold, silver, and aluminum, and both metals a and b shown in FIG. 2 are alloyed to form alloy C shown in FIG. 3.

Note that the method for alloying chromium with gold, silver, and aluminum is not limited to the above method; for example, a tuning fork crystal resonator formed as described above in an inert gas (nitrogen gas, etc.) may be used. This objective can also be achieved by inserting a tuning fork crystal into the tuning fork crystal and subjecting the tuning fork crystal to high temperature treatment.

The method of forming an electrode using an alloy using such a diffusion effect is to first alloy chromium with gold, silver, and aluminum;
Electrodes can be formed more easily than methods in which electrodes are formed by subsequent vapor deposition.

Furthermore, the present invention is not only applicable to electrodes with a two-layer structure, but also applicable to electrodes with a three-layer structure or more.

Further, in the above embodiment, both the electrodes on the main surface and the side surfaces of the tuning fork crystal resonator are alloyed, but the present invention is not limited to this, and only the electrodes on the main surface or the side surfaces are alloyed with chromium and gold. It goes without saying that a multilayer structure of silver and aluminum may be formed and alloyed.

Furthermore, the present invention is not limited to combinations of chromium and gold, silver, and aluminum, but equivalent combinations of metals, such as nickel (N1) and gold.

It may also be a combination of 3 pieces, aluminum, soot (Sn) and gold, 3 pieces, aluminum, copper (Cu) and gold, silver, or aluminum.

Furthermore, it goes without saying that the present invention can be applied to various types of crystal resonators, and is not limited to the tuning fork type crystal resonator in the above embodiments.

As mentioned above, when an electrode with a two-layer structure or more is alloyed, the alloyed metal has a
At the same time as its hardness decreases, its hardness increases compared to a simple substance such as gold. As a result, the stress exerted by the electrode on the crystal resonator is reduced compared to the stress caused by chromium alone.

Furthermore, this alloyed metal is less likely to cause so-called whiskers than gold or the like alone, and the phenomenon of being eaten away by solder or the like is reduced.

Effects of the Invention As explained in detail above, the present invention provides a quartz crystal resonator having electrodes on a quartz plate, in which the electrodes are used as a diffusion means between at least two or more metal thin films laminated on the quartz plate. [1) CI
[2] It is possible to prevent an increase in the value of the crystal resonator, and it is also possible to prevent an increase in the frequency change of the crystal resonator due to aging, [2] it is difficult to cause scratches on the surface of the alloy during the manufacturing process of the crystal resonator, and [3]
It can prevent so-called beards caused by gold, silver, etc., and also [
4] It has the effect of improving impact resistance without reducing the adhesion force between the fixed portion of the crystal resonator and the terminal.

The present invention also provides a method for manufacturing a crystal resonator having electrodes on a crystal plate, in which a first metal thin film is formed on the crystal plate, and a second metal thin film is formed on the first metal thin film. Since the electrodes are formed by laminating the first and second metal thin films and alloying the first and second metal thin films using a diffusion means, it is possible to easily manufacture a crystal resonator having alloyed electrodes. have

[Brief explanation of the drawing]

FIG. 1, FIG. 2, and FIG. 3 are diagrams showing an embodiment of the present invention when the present invention is implemented with a tuning fork crystal resonator,
FIG. 1 is a perspective view of a tuning-fork crystal resonator according to the present invention, and FIGS. 2 and 3 are cross-sectional views of a vibrating arm portion of the tuning-fork crystal resonator according to the present invention. 1.2... Vibrating arm 3.4, 5, 6, 7, 8, 9, 10 Conflict/Electric
Oi patent applicant Nippon Dempa Kogyo Co., Ltd. Representative Patent attorney Tsuji
Truth (1 other person) Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) In a quartz crystal resonator having electrodes on a quartz plate, at least two types of electrodes are laminated on the quartz plate.
A crystal resonator characterized in that it is formed of an alloy layer formed by diffusion means between two metal thin films. (2) In a method for manufacturing a crystal resonator having an @ pole on a crystal plate, a first metal thin film is formed on the crystal plate, and a second metal film is formed on the first metal film. ' = A method for manufacturing a crystal resonator, which comprises forming a V film with a product of J·K, and alloying the first and second metal thin films using a diffusion means to form an electrode.