JPS6349902B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a hermetic terminal having a gold plating layer.

Hermetic terminals are widely applied in various fields,
There are various shapes and structures depending on the application, but basically, as shown in Figure 1, the metal outer ring 1
A lead wire 3 is sealed in an airtight and insulating manner through a glass 2. There are two types of airtight terminals of this type: one is called a compression sealing type, and the other is a matching sealing type. In the former case, the metal outer ring 1 is made of iron or low carbon steel, the glass 2 is made of soda glass such as soda barium glass or soda lime glass, and the lead wire 3 is made of an iron-nickel alloy (50% Fe, 50% Ni). The linear expansion coefficient α ₁ of the metal outer ring 1 and the linear expansion coefficient α ₂ of the glass 2 are set in the relationship α ₁ >α ₂ , and strong compressive stress is applied to the glass 2 by the metal outer ring 1. This is something that can be added. On the other hand, in the latter case, the metal outer ring 1 and the lead wire 3 are made of an iron-nickel-cobalt alloy (53% Fe,
28% Ni, 18% Co), and uses borosilicate glass as the glass 2. The linear expansion coefficient α ₁ , α 3 of the metal outer ring 1 and the lead wire ₃ and the linear expansion coefficient α ₂ of the glass 2 are The relationship is set to α ₁ = α ₃ ≒ α ₂ . The former has the advantage of being inexpensive and having high mechanical strength, but on the other hand, concentric compressive strain occurs in the glass 2, there are design restrictions on the sealing part, and the insulation of the surface of the glass 2 deteriorates depending on the temperature. The disadvantage is that it is easy to change. On the other hand, the latter has advantages such as being stable over a wide temperature range with no distortion, being able to design an arbitrary shape, having high reliability in airtightness, and having good insulation stability on the surface of the glass 2. However, since the iron-nickel-cobalt alloy is very expensive, the cost is high, and the mechanical strength is relatively poor.

Therefore, the applicant first proposed an iron-nickel alloy (Fe58) called 42 alloy as shown in Figure 2.
We have proposed an airtight terminal in which a lead wire 6 made of an iron-nickel-cobalt alloy is hermetically and insulatively sealed within a metal outer ring 4 made of borosilicate glass 5. Since the iron-nickel alloy is much cheaper than the iron-nickel-cobalt alloy, this hermetic terminal can be manufactured at a lower cost than the matched sealing type hermetic terminal, and the metal outer ring 4 has a linear expansion. Since the coefficient α ₄ (52×10 ^-7 /℃) and the linear expansion coefficient α ₅ (47×10 ^-7 /℃) of glass 5 have a relationship of α ₄ >α ₅ , compressive stress is applied to glass 4. , there is an advantage that mechanical strength is also improved.

Now, in such an airtight terminal, if the base material of the metal outer ring 4 and the lead wire 6 is left exposed, it will cause rusting and cause various problems.
Therefore, the surfaces of the metal outer ring 4 and the lead wires 6 are plated to prevent rust. This anti-rust plating is generally electrical nickel plating, chemical nickel plating or gold plating.

However, in the case of gold plating, if gold plating is applied directly to the metal outer ring 4 and the lead wire 6, bending stress is likely to be applied particularly to the lead wire 6, causing stress corrosion cracking, so it is common to apply nickel plating etc. to the base. It is.

Conventionally, as shown in FIGS. 3 and 4, after the lead wires 6 are hermetically and insulatively sealed inside the metal outer ring 4 through the glass 5, the surfaces of the metal outer ring 4 and the lead wires 6 are sealed. Since the nickel plating layers 7 and 8 and the gold plating layers 9 and 10 were formed, the following problem occurred. That is, when forming the nickel plating layers 7 and 8 by electroplating, the metal outer ring 4 and the lead wire 6 are insulated via the glass 5, so in order to plate both, they must be wire-bound. It is necessary to keep the wires at the same potential due to various methods, and the work of tying and removing wires is extremely complicated. Further, when barrel plating is carried out, there are problems in that the lead wire 6 is bent and the glass 5 is cracked. On the other hand, if the nickel plating layers 7 and 8 are formed by a chemical plating method, there is no need to perform wire binding work to bring the metal outer ring 4 and the lead wire 6 to the same potential.
The plating work is extremely easy, but if chemical nickel plating is applied directly onto the metal outer ring 4 and the lead wire 6, it is possible to braze this airtight terminal or to braze other items onto the airtight terminal during the heating process. The chemical nickel plating layer is hardened and its linear expansion coefficient is
130×10 ^-7 /℃, which is chemically distorted due to the extreme difference in linear expansion coefficient (47×10 ^-7 /℃) of the iron-nickel-cobalt alloy that makes up the metal outer ring 4 and the lead wire 6. There is a problem in that the nickel plating layer cracks, causing defects such as poor solder adhesion, discoloration, and stains.

Therefore, the main object of the present invention is to provide a method for manufacturing an airtight terminal having a gold plating layer, in which the underlying nickel plating layer can be easily formed and does not cause cracks.

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

FIG. 5 shows a process block diagram for explaining a method according to an embodiment of the present invention, and FIG. 6 shows an enlarged cross-sectional view of a main part of a hermetic terminal manufactured by the above method. In FIG. 6, the same parts as in FIG. 4 are given the same reference numerals. First, 42 alloy (Fe58%,
Metal outer ring 4 consisting of Ni42%) and iron-nickel-cobalt alloy (Fe53%, Ni28%, Co18%)
Electric nickel plating layers 9 and 10 of about 1.5 to 8 μm are formed on the entire surface of the lead wire 6, and the lead wire 6 is hermetically and insulatively sealed inside the metal outer ring 4 via the borosilicate glass 5. Gold plating layers 11 and 12 having a thickness of about 0.2 to 2.0 μm are formed on the surfaces of the metal outer ring 4 and the lead wires 6.

According to the above manufacturing method, the metal outer ring 4 is
and the lead wire 6 as a single electric nickel plating layer 9,
10, it can be easily plated using the barrel plating method, and compared to the case where the electric nickel plating layers 7 and 8 are formed after sealing, the metal outer ring 4
Not only is there no need for wire binding to bring the lead wire 6 and the lead wire 6 to the same potential, but there is also no bending of the lead wire 6 or glass cracking. In addition, compared to the case where a chemical nickel plating layer is formed, the hardness increases due to subsequent heating, and cracks may occur in the nickel plating layer due to stress due to the difference in linear expansion coefficient between the metal outer ring 4 and lead wire 6 and the nickel plating layer. Nor.

In the above embodiment, for convenience of explanation, a single lead wire 6 is placed inside a simple flanged cylindrical metal outer ring 4.
Although we have described the case where a plurality of lead wires 6 are sealed within the cylindrical metal outer ring 4, it is also possible to seal a plurality of lead wires 6 in a cylindrical metal outer ring 4, or to seal a flat plate like a stem substrate in a stem for a semiconductor device. A plurality of through holes are drilled in the metal outer ring, and one hole is inserted into each of these through holes.
A book or a plurality of lead wires may be sealed.

Furthermore, in the above embodiment, the case where the metal outer ring 4 is made of an iron-nickel alloy with a specific composition has been explained, but it may be made of a material with a linear expansion coefficient of 75×10 ^-7 /°C or less in a temperature range of 450°C or less. Similar problems occur in metal outer rings and lead wires, so this invention can be applied.

As described above, the present invention includes a step of forming an electric nickel plating layer on a metal outer ring and a lead wire made of a material having a linear expansion coefficient of 75×10 ^-7 /°C or less in a temperature range of 450°C or less, and Since the method includes the steps of hermetically and insulatively sealing the lead wire inside the ring via borosilicate glass, and the step of forming a gold plating layer on the surface of the metal outer ring and the lead wire, the base nickel plating layer is It can be easily formed without the need for wire binding work, does not cause bending of lead wires or cracking of the glass, and does not increase in hardness and break like chemical nickel plating layers even when heated in the post-process. , it is possible to obtain an airtight terminal having a gold plating layer.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a typical airtight terminal, Fig. 2 is a sectional view of an airtight terminal which is the background of this invention, and Fig. 3 is a process block diagram for explaining a method of manufacturing an airtight terminal prior to this invention. 4 is an enlarged sectional view of the main part of an airtight terminal manufactured by the method, FIG. 5 is a process block diagram for explaining one embodiment of the method of the present invention, and FIG. 6 is a diagram illustrating the method. FIG. 3 is an enlarged cross-sectional view of the main part of the airtight terminal thus manufactured. 4...Metal outer ring, 5...Glass, 6...Lead wire, 9, 10...Electric nickel plating layer, 11,
12...Gold plating layer.

Claims (1)

[Claims] 1 The coefficient of linear expansion in the temperature range below 450℃ is
A process of forming an electric nickel plating layer on a metal outer ring made of a material with a temperature of 75×10 ^-7 /℃ or less and a lead wire made of an iron-nickel-cobalt alloy, and bonding these metal outer rings and the lead wire through borosilicate glass. A method for manufacturing an airtight terminal, comprising the steps of: hermetically and insulatively sealing the metal outer ring and the lead wire; and forming a gold plating layer on the metal outer ring and the lead wire.