JPS6048855B2 - Airtight sealing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an airtight sealing method for sealing a metal outer ring made of copper-clad Kovar with glass.

Hermetically sealed bodies in which a metal outer ring made of copper-clad Kovar is sealed to glass are widely used.

For example, Figure 1 shows a vertical cross-sectional view of an airtight container for a crystal resonator, where 1 is a copper cap, 2 is an airtight terminal stem, and 3 is made of copper and Kovar (53% Fe, 28% Ni, 18% Co).
The cladding material of No. 4 is drawn and press-molded to form the flange No. 6.
and through holes 7, 7, the upper surface of the flange 6 is made of copper 3, and the inside of the through holes 7, 7 is made of Kovar 4.
Kovar lead wires 9, 9 are hermetically and insulatively sealed into the through holes 7, 7 via borosilicate glasses 8, 8. 10 is a crystal resonator, which is fixed to the tips of lead wires 9, 9.

The flange portion 1a of the cap 1 is superimposed on the flange 6 of the hermetic terminal stem 2 and fixedly sealed by cold pressure welding. Prior to glass sealing, the metal outer ring 5 is subjected to preliminary oxidation treatment to improve airtight sealing between the Kovar 4 and the glass 8, and the surface of the Kovar 4 is coated as shown in FIG. With the oxide film 4a formed, the glass bullet 80 and the lead wire 9 are combined using a graphite sealing jig 11 and heated to about 1000°C in a neutral or weakly reducing atmosphere to seal the glass bullet. 80 is melted and sealed.

However, the preliminary oxidation treatment
Since the heating is carried out by heating to 000C, not only an oxide film 4a is formed on the surface of the Kovar 4, but also an oxide film 3a of cuprous oxide, cupric oxide, etc. is formed on the surface of the copper 3.
If there is an oxide film 3a on the surface of the copper 3 in this way, the above-mentioned 10
Since the vapor pressure of the oxide is high at a sealing temperature of approximately 00°C, the oxide evaporates and adheres to the sealing jig 111, causing severe wear and tear on the sealing jig 11. In addition, the oxide film 4a on the surface of Kovar 4
There is a risk that the oxide of copper 3 will fly on top and the sealing strength between Kovar 4 and glass 8 will decrease. Therefore, the main object of the present invention is to provide an airtight sealing method for sealing glass by pre-oxidizing a copper clad metal outer ring made of Kovar.
It is an object of the present invention to provide an airtight sealing method that prevents wear and tear on a sealing jig and provides high sealing strength between Kovar and glass.

To summarize, the present invention is characterized in that after preliminary oxidation of a metal member made of copper-clad Kovar, only the copper oxide film is selectively removed and the metal member is sealed with glass.

The above objects and other objects and features of the present invention will become more apparent from the detailed description of the invention given with reference to the drawings.

First, to explain the case in which the present invention is applied to the airtight terminal stem 2 shown in FIG. 1, cladding materials of copper 3 and Kovar 4 are drawn and press-molded, and as shown in FIG. A metal outer ring 5 having holes 7, 7 is manufactured and heated to 700 to 900°C in air.

Then, as shown in FIG.
a is formed. Next, the metal outer ring 5 having the oxide films 3a and 4a is soaked in a hydrochloric acid solution of 1:1 hydrochloric acid:water for 10 to 10 minutes.
Immerse between beds. Then, the oxide film 3a on the surface of the copper 3 has a kind of big J-ring effect (Pickling actiO).
n) causes it to stand out from the copper 3. Next, this was mixed with 5-20% hydrogen peroxide solution, 2-10% sulfuric acid, 5-15% phosphoric acid, and 0.01-0% anionic surfactant.
．． When immersed in a 0.5% aqueous solution, only the oxide film 3a floating above the copper 3 is dissolved and removed, leaving the oxide film 4a only on the surface of the Kovar 4, as shown in FIG. Note that cupric oxide can be dissolved by simply immersing it in hydrochloric acid, but it is difficult to dissolve cuprous oxide, and furthermore, immersion in hydrochloric acid for a long time will cause oxidation of the copper. Since not only the film 3a but also the Kovar oxide film 4a is dissolved and removed, good results can be obtained by immersing the film in the aqueous solution after a short time in the hydrochloric acid solution.

After this, as shown in Figure 6, graphite. The metal outer ring 5 from which the oxide film 3a has been removed using a sealing jig 11 manufactured by
, the glass tablet 80 and the lead wire 9 are assembled in a predetermined relationship, and the
The metal/metallic outer ring 5 and the lead wire 9 are sealed airtightly and insulatively via the glass 8 in which the glass tablet 80 is fused by heating to about 0°C.

During this glass sealing, since the oxide film 3a on the surface of the copper 3 is removed, damage to the sealing jig 11 due to evaporation of the copper oxide film 3a and sealing between the Kovar 4 and the glass 8 are prevented. There are no problems such as a decrease in adhesion strength. FIG. 7 shows a longitudinal sectional view of another example of an airtight terminal stem 12 for a crystal resonator to which the present invention is suitable.

In the figure, 13 is a metal outer ring made by drawing and pressing cladding materials of copper 3 and Kovar 4 with Kovar 4 on the inside, and has a flange 14 and a top plate part 15.
The upper surface of 4 is made of copper 3, and two through holes 16, 16 for sealing lead wires are bored near both ends of top plate portion 15. The metal outer ring 13 is filled with borosilicate glass 17, and lead wires 18, 18 made of Kovar are hermetically and insulated sealed to the through holes 16, 16 via the glass 17. To put it simply, this airtight terminal stem 12 has the airtight terminal stem 2 shown in FIG. 9, 9 are sealed, whereas lead wires 18, 18 are different from each other in that they have an upwardly convex shape, and lead wires 18, 18 are sealed by a common glass 17.
When manufacturing such an airtight terminal stem 12, the same problems as described above occur, and the same effects can be obtained by applying the present invention. FIG. 8 shows a longitudinal sectional view of a lens cap 19 for an optical semiconductor device to which the present invention is suitable.

In the figure, reference numeral 20 denotes a metal outer ring formed by drawing and press-molding cladding materials of copper 3 and Kovar 4 so that the copper 3 is on the inside, and has a flange 21 and a top plate part 22. It is made of copper 3, and there are through holes 2 in the top plate part 22.
It has 3. A hemispherical glass lens 24 is hermetically sealed in the through hole 23 portion. When manufacturing such a lens cap 19, problems similar to those described above occur,
Similar effects can be obtained by applying this invention. In the above embodiments, the present invention was explained in the specific structure of specific articles such as an airtight container for a crystal resonator and a lens cap.
The present invention is not limited to this in any way, but can be applied to any case where a metal outer ring made of copper-clad Kovar is pre-oxidized and sealed with glass.

As described above, the present invention is to pre-oxidize a metal outer ring made of copper-clad Kovar, remove only the copper oxide, and seal it with glass using a sealing jig made of graphite. Problems such as wear of the sealing jig and reduction in sealing strength caused by the oxide film can be solved, and high quality glass sealed bodies can be efficiently produced.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of an example of an airtight container for a crystal resonator;
The figure is an enlarged vertical cross-sectional view of the main part before sealing to explain the conventional method, and Figures 3 to 6 are vertical cross-sectional views of each process when the method of the present invention is applied to an airtight terminal stem for a crystal resonator. Fig. 3 is a longitudinal sectional view of the metal outer ring, Fig. 4 is an enlarged longitudinal sectional view of the main part of the metal trap outer wire after preliminary oxidation, and Fig. 5 is the main part of the metal outer ring with the copper oxide film removed. Fig. 6 is an enlarged longitudinal sectional view of the main part before sealing. 7 and 8 show longitudinal sectional views of other examples of hermetically sealed bodies suitable for this invention, in which FIG. 7 shows an airtight terminal stem for a crystal resonator, and FIG. 8 shows a lens cap for an optical semiconductor device. It is. 3... Copper, 3a... Copper oxide film, 4... Kovar, 4a... Kovar oxide film, 5, 13, 20... ...Metal outer ring, 7
, 16, 23... Through hole, 8, 17, 24...
...Glass, 9,18...Lead wire, 11.
...Sealing jig.

Claims (1)

[Scope of Claims] 1. After preliminary oxidation of a metal outer ring made of copper-clad Kovar, only the copper oxide is removed, and glass is sealed to at least the Kovar portion using a graphite sealing jig. Features an airtight sealing method. 2 After preliminary oxidation, a metal outer ring made of copper-clad Kovar is immersed in a hydrochloric acid solution, and then immersed in a 5-30% hydrogen peroxide solution and a sulfuric acid solution.
10%, 5 to 15% of phosphoric acid, and 0.01 to 0.05% of an anionic surfactant to remove only copper oxides. Sealing method.