JPH02298110A - Crystal resonator - Google Patents

Abstract

PURPOSE:To prevent flow of a brazing metal to an exciting electrode at bonding between a lead wire and an external connection electrode by making electric connection of an external connection electrode to an exciting electrode and the external connection electrode to an external connection side electrode with a 1st layer film around the lead soldered part. CONSTITUTION:The 1st layer film exposure section 51 is provided to etch a 2nd layer film of an external connection electrode 41 and to take the electric connection between the external connection electrode 41 and the exciting electrode 2 with the 1st layer film only around the external connection electrode 41. A lead wire 7 is mounted to a plug 9 via a glass 8 and bonded to the external connection electrode 41 with a metallic solder member such as solder. The electric connection between the external connection electrode 41 and the external connection side electrode 42 is implemented with the 1st layer film 52 only by providing the 1st layer exposed part 51. Thus, it is prevented that the flow of the brazing metal from the external connection electrode 41 to the exciting electrode 2 and from the external connection electrode 41 to the external connection side electrode 42.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an external conducting electrode structure of a crystal resonator.

[Prior Art] A conventional external conductive electrode structure of a crystal resonator is described in Japanese Patent Publication No. 64-2288. As shown in Fig. 4, this creates a flow-stopping part in which it is difficult to form a eutectic alloy with the metal brazing material on the external conductive electrode, that is, a second layer film exposed part 25, and the metal brazing material is excited from the external conductive electrode. This is intended to prevent the vibration balance from being lost due to the flow of the brazing metal material by preventing it from being transmitted to the electrodes.

[Problems to be Solved by the Invention] However, in the conventional technology, in order to obtain low crystal impedance (hereinafter abbreviated as IC value) and excellent temperature characteristics, when an electrode is provided on the side surface of the external conductive electrode section, metal The brazing material flows into the excitation electrode, resulting in the vibration balance of the crystal resonator being disrupted, resulting in deterioration of characteristics such as the Q value, stability of oscillation frequency, and impact resistance, as well as deterioration of the long-term reliability of the above-mentioned characteristics. A problem arises.

A conventional example is shown in FIGS. 4 and 5. FIG. 4 is an enlarged plan view of the vicinity of the external conductive electrode, and FIG. 5 is a sectional view when viewed from the direction of FIG. 4.

For the reasons mentioned above, external conduction 1! When an electrode is provided on the extreme side,
As is clear from FIG. 5, the external conductive electrode 21, the external conductive side electrode 22, and the rear external conductive electrode 23 are formed from one film, and the connection between the 14 external conductive poles and the lead wire is normally performed for bonding. A lead wire plated with a metal brazing material is applied to the external conductive W pole 21, and the metal brazing material is melted by applying a temperature of about 500°C or less, and the metal brazing material and the external conductive electrode (second layer film) are melted. This is achieved by creating a eutectic alloy. However, at the time of this bonding, since the external conductive electrode 21, the external conductive side electrode 22, and the back external conductive electrode 23 are formed as one film, the metal brazing material flows from the external conductive electrode 21 to the external conductive fII11 surface electrode 22. Since the external conductive side electrode 22 is formed of the same second layer film as the excitation electrode, the metal brazing material that has flowed into the external conductive side electrode 22 will also flow into the excitation electrode 2, as described above. problem will occur.

Therefore, the present invention aims to solve these problems, and aims to have low IC value, excellent temperature characteristics, high Q value, stable oscillation frequency, strong impact resistance, etc. Our goal is to provide crystal oscillators with unique characteristics.

[Means for Solving the Problems 1] In the crystal resonator of the present invention, the first layer film is formed of a metal that is difficult to eutectic with the metal brazing material, as an excitation electrode of a crystal oscillation piece partially provided with a support portion. , the second layer film is formed from a metal that is easily eutectic with the metal brazing material, and a part of the excitation 1f pole is extended to the support part to form an external conductive electrode, and a direct wire is connected to the external conductive electrode. In the crystal resonator, the electrical connection between the external conduction electrode and the excitation electrode and the crystal oscillation piece plane electrode of the external conduction electrode and the side electrode is made by contacting the first layer film around the lead wire joint. It is characterized by being made up of.

[Embodiment] FIG. 1 is a plan sectional view of an embodiment of the present invention.
l is a crystal oscillation piece, and an excitation electrode 2 is attached to the crystal oscillation piece l.
is formed. Excitation 1i pole 2 is crystal oscillation piece support part 3
1 to form an external conductive electrode 41. The second layer film of the external conductive electrode 41 is etched around the external conductive electrode 41 using a photo-etching technique, and in order to establish an electrical connection with the external conductive electrode 41 with an excitation amount of 1fi2 only using the first layer film. A membrane exposed portion 51 is provided. The lead wire 7 is attached to the plug body 9 via the glass 8, and the lead wire is joined to the external conductor'@1fi41 with a metal brazing material such as solder. 6 is a case, and after joining the crystal oscillation piece and the lead wire as described in 5@, it is press-fitted into the plug body 9 in a vacuum to complete the crystal resonator.

The material of the electrode formed on the crystal oscillator piece is such that the first layer film is a metal film such as chromium, which is difficult to eutectic with the metal brazing material, and the second layer film is a metal film such as gold or silver, which is easily eutectic with the metal brazing material. A membrane is preferred.

FIG. 2 is an enlarged view of the crystal oscillation piece near the external conducting electrode of FIG. 1, and FIG. 3 is a sectional view when viewed from the direction of FIG. 2. As is clear from FIG. 3, the electrical connection between the external conductive electrode 41 and the external conductive side electrode 42 is achieved only through the first layer film 52 by providing the first layer film exposed portion 51. In addition, in FIG. 3, the external conductive electrode 41 and the back external conductive electrode 4
3 have the same shape, but the present invention is not limited to this, and the first layer film exposed portion 5 is formed only on the side where the lead wire is joined.
1 may be provided. However, if the structure of the present invention is applied only to the lead wire joining surface, it is necessary to classify the front and back sides of the crystal oscillator pieces when joining the lead wires, which takes a lot of man-hours, so it is desirable that the front and back sides have the same shape.

FIG. 1 shows a state in which the crystal oscillation piece is joined to the lead wire, and the process of this joining will be explained in detail with reference to FIGS. 2 and 3.

The crystal oscillator piece and the lead wire are usually joined by applying a lead wire plated with a metal brazing material such as solder to the external conducting electrode 41 shown in Fig. 2, and applying a temperature of about 500°C or less to melt the metal brazing material. , the melted metal brazing material becomes the external conducting electrode 4
This is achieved by creating a eutectic alloy with 1. As described above, the material of the external conductive electrode 41 is a metal film that is easily eutectic with a metal brazing material such as gold or silver, so that it can be easily joined to the lead wire.

The present invention provides an external conductive electrode 41 around the lead wire joint.
and excitation electrode 2, external conduction electrode 41, and external conduction measurement surface electrode 4.
By making the electrical connection of 2 only through the first N film 52,
This prevents the metal brazing material from flowing into the excitation electrode. In other words, by providing the exposed portion 51 of the first layer film that is difficult to eutectic with the metal brazing material, the metal brazing material is transferred from the external conductive electrode 41 to the excitation electrode 2 and from the external conductive electrode 41 to the external conductive side electrode. This prevents it from flowing into the 42.

The electrical connection between the external conductive electrode 41 and the excitation electrode 2, and between the external conductive electrode 41 and the external conductive side electrode 42 can be easily achieved by the photo-etching technique as described above, using the first layer film. Note that the first layer film exposed portion 51 may have a size of 10 to 50 μm.

As mentioned above, the embodiment of the present invention has been described using the tuning fork type main island resonator shown in FIG. It can also be applied to crystal oscillators equipped with excitation electrodes that utilize second-order harmonics.

[Effects of the Invention 1] As described above, according to the present invention, the electrical connection between the external conductive electrode and the excitation electrode, and between the external conductive electrode and the external conductive side electrode is formed by the first layer film around the lead wire joint. This completely prevents the metal brazing material from flowing into the excitation electrode when connecting the lead wire and the external conductive electrode, making it possible to use a crystal resonator with layered characteristics such as a high Q value, stable oscillation frequency, and strong impact resistance. can be done. Furthermore, since it is possible to prevent the metal brazing material from flowing into the excitation electrode due to changes over time, long-term reliability is also extremely high. Furthermore, since the crystal resonator of the present invention is provided with external conductive side electrodes, the IC value is low.
Excellent temperature characteristics can be obtained.

In addition, since the part where the metal brazing material flows is limited to the inside of the exposed part of the first layer film, sufficient bonding strength can be obtained even if less metal brazing material is required for joining than before, which makes it possible to reduce the amount of metal brazing material. In other words, cost reduction becomes possible.

The present invention has one or more significant advantages.

[Brief explanation of drawings]

FIG. 1 is a main plan cross-sectional view showing an embodiment of the crystal resonator of the present invention. FIG. 2 is a plan view showing the vicinity of the external conducting electrodes of the embodiment of the crystal resonator of the present invention. Figure 3 shows an external conduction type (÷
A sectional view showing the vicinity. FIG. 4 is a plan view showing the vicinity of external conducting electrodes of a conventional crystal resonator. FIG. 5 is a sectional view showing the vicinity of the external conducting electrode of a conventional crystal resonator. l...Crystal oscillation piece 2...1iill Oscillation electrode 3...Crystal oscillation piece support portion 21.41...External conduction electrode 22.42...External conduction side surface Electrode 23.43... Back external conduction electrode 51... First Fl film exposed portion 24.52... First layer film 6... Case 7... Lead wire 8... ...Glass 9...Plug body or more

Claims (1)

[Claims] As an excitation electrode for a crystal oscillation piece partially equipped with a support part, the first layer film is formed from a metal that is difficult to eutectic with the metal brazing material, and the second
The layer film is formed from a metal that is easily eutectic with the metal brazing material, a part of the excitation electrode is extended to the support part to form an external conduction electrode, and the external conduction electrode and the lead wire are connected to the metal brazing material. In the crystal resonator formed by joining the external conductive electrode and the excitation electrode, and the crystal oscillation piece plane electrode of the external conductive electrode and the side electrode, electrical connections are made by the first layer film around the lead wire joint part. A crystal oscillator characterized by: