JPH08269565A - Production of sealing tube of crystal oscillator - Google Patents

Abstract

PURPOSE: To shallow the recessed parts of flaws and to improve the adhesion state of plating without forming oxidized films by subjecting a sealing tube obtd. by press working to an annealing treatment in a hydrogen atmosphere at a specific temp. CONSTITUTION: The sealing tube of a crystal oscillator formed by pressing is subjected to the annealing treatment for about two to three hours of heating up time and about one hour of holding time in the hydrogen atmosphere of 700 to 1000 deg.C. The metal atoms of the sealing tube material are moved by this high-temp. treatment, and the recessed parts of the numerous flaws of a width of about 1μm, length of about several mm and depth of about 2 to 3μm generated by pressing are shallowed. As the result, the adhesion state of the plating of the sealing pipe is improved. The press sealing type cylindrical crystal vibrator which has high reliability and is free from problems, such as occurrence of leakage, is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sealed tube for a press-fitted sealed type quartz crystal resonator.

[0002]

2. Description of the Related Art A sealing tube used for a crystal oscillator is formed by press working (deep drawing). As the material of the sealing tube, 42 Ni of nickel and 42 Ni of iron and nickel white are used.

The sealing tube formed by press working is plated on its inner surface to enhance airtightness with the airtight terminal. Copper plating is applied to the base to a thickness of 2 μm to 5 μm, and then solder plating is applied to a thickness of 10 μm. The sealing tube having the plated inner surface is press-fitted and sealed in an airtight terminal in which a crystal piece is assembled to form a crystal resonator.

[0004]

FIG. 1 is a view showing a sealing tube formed by press working. Reference numeral 1 is a sealed tube, and 2 is a flaw. Since the sealed tube 1 is formed by press working (deep drawing), the inner surface of the sealed tube is scratched innumerably at that time. The scratches are often vertical in the pressing direction, and have a width of 1 μm, a length of several mm, and a depth of 2 to 3 μm.

FIG. 2A is a partial cross-sectional view of the sealing tube showing a state after the plating process. 3 is a plated part. When the inner surface of the sealing tube is plated with the scratches left, the scratches 2 are covered with the plating portion 3, and the liquid such as the plating solution or gas is trapped in the recesses of the scratches. If the sealing tube is press-fitted and sealed into the hermetic terminal in such a state, the liquid such as the confined plating solution or gas leaks into the sealing tube, and the CI value is deteriorated.

FIG. 2B is a partial cross-sectional view of the sealing tube showing another state after the plating process. Plating does not work well in the recessed portions of the scratches, and the plated state as shown in FIG. 2B occurs, so that leakage occurs even if sealing is performed. Therefore, there is a problem that the CI value is significantly deteriorated, the characteristics are deteriorated, and the yield is reduced.

Therefore, the present invention is intended to provide a method of manufacturing a sealed tube for making a recessed portion of a flaw formed by press working shallow so as to improve the adhered state of plating.

[0008]

In order to solve the above problems, the present invention has the following constitution. Press the sealed quartz crystal tube from 700 ℃ to 100 ℃
Annealing is performed in a hydrogen atmosphere at 0 ° C.

[0009]

[Example] A sealed tube formed by press working is 700
Annealing treatment is performed in a hydrogen atmosphere at a temperature of ℃ to 1000 ℃. The temperature is raised from 700 ° C. to 1000 ° C. in 2 hours to 3 hours, heat-treated for about 1 hour, and then lowered in 2 hours to 3 hours.

FIG. 3 is a partial sectional view of the sealed tube after the annealing treatment. By heat-treating the sealed tube at a high temperature, the metal atoms of the sealed tube material move and the depth of the recessed portion of the scratch can be reduced as shown in FIG. Although some recesses are left, it is extremely shallow, so even if plating is performed, the plating will be sufficiently applied along the inner surface of the sealing tube, so that liquids such as plating liquid and gas will be trapped. It does not cause the problem of being unplated.

FIG. 4 (a) is an electron micrograph of the inner surface of the sealed tube before the annealing treatment, and FIG. 4 (b) is an electron micrograph of the inner surface of the sealed tube after the annealing treatment. 4 (a), 4 (b)
Is taken at a magnification of 3000 times.
Comparing (a) and (b), it can be seen from the photograph after the annealing treatment of (b) that the surface is clearly changed due to the movement of metal atoms, and it can be confirmed that the concave portion of the scratch becomes shallow.

The annealing treatment in the atmosphere is optimally performed in a hydrogen atmosphere because an oxide film is formed on the sealed tube and the plating treatment cannot be performed.

The high temperature heat treatment is performed at a temperature of 700 ° C. or lower.
The depth of the scratch cannot be shallow. Also, 1000
At a temperature of ℃ or more, although the depth of the scratch can be made shallow, there is a problem that the sealing tube itself is deformed.
Therefore, it is preferable to set the temperature within the range of 700 ° C to 1000 ° C.

The inner surface of the sealing tube is usually plated and then press-fitted into the airtight terminal.
If S304, Kovar, or the like is used, press-fit sealing with the airtight terminal can be performed without performing plating treatment. Further, even if the above materials are used, scratches will occur during pressing, but the high temperature heat treatment can reduce the depth of the scratches, so if the manufacturing process is simplified and cost is reduced, It is better to use the one.

[0015]

EFFECTS OF THE INVENTION By making the recesses of scratches shallow by annealing, it is possible to prevent deterioration of the CI value due to gas generation.
Since problems such as leaks can be solved, a highly reliable crystal unit can be obtained.

[Brief description of drawings]

FIG. 1 is a view showing a sealing tube formed by press working.

FIG. 2 (a) is a partial cross-sectional view of a sealed tube showing a state after plating, and FIG. 2 (b) is a partial cross-sectional view of a sealed tube showing another state after plating.

FIG. 3 is a partial cross-sectional view of a sealed tube after annealing treatment.

FIG. 4 (a) is an electron micrograph of the inner surface of the sealed tube before annealing, and (b) is an electron micrograph of the inner surface of the sealed tube after annealing.

[Explanation of symbols]

 1 Sealed tube 2 Scratch 3 Plated part

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 8, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

FIG.

[Figure 3]

[Fig. 2]

[Figure 4]

Claims (1)

[Claims] 1. A method of manufacturing a sealed tube for a crystal resonator, which comprises subjecting a sealed tube of a crystal resonator, which has been pressed, to annealing treatment in a hydrogen atmosphere at 700 ° C. to 1000 ° C.