JPS636153B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing a DHD type glass-sealed diode electrode, and more specifically, it is obtained by combining an electrode having a small diameter portion and a large diameter portion by nailing or molding. In the leadless diode electrode, a copper layer is coated by a method of fitting a copper pipe, and then an iron wire obtained by wire drawing is applied.
This method is characterized by cutting the nickel wire and forming a cuprous oxide film on the copper layer on the electrode surface after nailing or shaping.

Most of the diode electrodes currently on the market have a semiconductor element 3 mounted between electrodes 2 with lead wires 1 at both ends, and a sealing glass 4 surrounding the electrodes 2, as shown in Fig. 1. This is a sealed DHD type glass-sealed diode electrode, and when it is mounted on a printed circuit board etc., a long and thin lead wire 1 must be inserted into the mounting hole of the printed circuit board.

For this reason, the work requires a large number of man-hours, and the manufacturing process of the diode itself also includes lead wires, which is a major hindrance to automated work.

For this reason, a DHD type glass-sealed leadless diode, which does not have lead wires and is easy to mount on a printed circuit board, as shown in FIG. 2, has been devised, and its demand is rapidly increasing.

The electrode 2 of such a leadless diode is made of a core wire 5 (for example, Fe-Ni) coated with a copper layer 6.
A composite wire (Fig. 3) with a borax glass layer or a cuprous oxide layer 7 applied to the surface of the wire (Fig. Electrode 2 consisting of a small diameter part 8 and a large diameter part 9
Prepare as.

Then, a second electrode is placed in the center of the electrode 2 having such a shape.
As shown in the figure, attach a semiconductor element 3 such as silicon,
A diode is obtained by sealing the electrode 2 with a sealing glass 4.

However, the borax glass layer or the cuprous oxide layer 7 on the surface of the electrode 2 is very brittle and is likely to peel off or crack when strong force is applied to it, such as during nailing or molding. For glass-sealed diodes, defects in the surface borax glass layer or cuprous oxide layer significantly reduce the airtightness after glass-sealing and become a major cause of leakage defects.

This invention was obtained as a result of studies to eliminate the above-mentioned drawbacks of DHD type glass-sealed diode electrodes, and it is a core wire coated with a copper layer, such as a Fe-Ni wire, by a method of fitting a copper pipe. Before carrying out the cuprous oxide treatment, the core wire is nailed to create an electrode 2 having a shape consisting of a small diameter part 8 and a large diameter part 9 as shown in Fig. 4, and then the surface of this electrode 2 is It is characterized by forming a cuprous oxide layer on the glass sealing part, thereby eliminating flaws in the glass sealing part, completely adhering to the glass, and increasing the reliability of the diode. We have succeeded in completely eliminating leak defects caused by this.

In particular, the small diameter portion 8 that comes into close contact with the glass is intentionally deformed to improve the wettability with the glass.
The method of the present invention is effective when creating electrodes with deformed shapes as shown in the figure.

As an example of the present invention, a method of surface oxidation treatment using cuprous oxide after nailing an electrode will be described below.

First, copper-coated 0.1
Prepare Fe-Ni wire drawn to ~1.5mmφ.
Then, by nailing this wire, an electrode 2 having a shape as shown in FIG. 4 is created.

At this time, in the next process of cuprous oxide treatment, the small diameter part 8
Since the end faces of the nails are also oxidized, Ag pellets 10 are crimped onto the end faces during nailing. Alternatively, when the Ag pellets are not pressed, the blackened portions of the end surfaces can be removed by washing only the end surfaces with hydrochloric acid after the cuprous oxide treatment.

The electrode 2 thus prepared is subjected to a continuous oxidation process as shown in FIG.

First, the electrode 2 is placed on the belt 12 rotated by the feed drive device 11, guided to the heating furnace 13, heated to 950°C or higher in the heating furnace, and then heated to a water temperature of 40°C.
The electrode 2 is continuously immersed in the water cooling tank 14 to be rapidly cooled, so that only a cuprous oxide film is formed on the surface of the electrode 2.

In conventional diamond wires, the borax liquid was applied uniformly to the surface and then baked again in a burner or heating furnace to form a borax glass layer, but in the case of wires with irregular shapes as shown in Figures 4 and 5, Even if an attempt was made to apply a borax solution to the glass, it was difficult to apply it uniformly, and the resulting borax glass layer was only non-uniform.

However, if the treatment method of this invention as shown in Fig. 6 is carried out, the copper surface will be heated uniformly no matter how irregular the copper surface is, so a cuprous oxide layer of a constant thickness can be obtained in the next step of water cooling. It will be done.

The surface of the electrode according to the present invention obtained in this way is free from peeling and flaws of the cuprous oxide film that are harmful to glass sealing, so that extremely high reliability of the diode can be obtained.

After sealing the glass using the electrode obtained by the method of this invention and the electrode obtained by the conventional method, the electrode was immersed in a 1.5% hydrochloric acid solution at 100°C for 15 minutes. When the corrosion depth was measured, the results shown in Figures 7A and 7B were obtained, and it was demonstrated that the electrode according to the present invention had extremely little acid corrosion as shown in Figure 7B, and the reliability of the diode was extremely high. Ta.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a diode with a lead wire, Figure 2 is a cross-sectional view of a leadless DHD type diode,
Figure 3 is a plan view of the electrode obtained by this invention;
5 is a perspective view similarly showing another embodiment, FIG. 6 is an explanatory view showing an example of the manufacturing process of the DHD type glass-sealed diode electrode of the present invention, and FIGS. 7 A and B is a chart showing the acid corrosion depth of electrodes obtained by the conventional method and the method of the present invention. 2... Electrode, 6... Copper layer, 7... Cuprous oxide layer,
8...Small diameter part, 9...Large diameter part.

Claims (1)

[Claims] 1. In a leadless diode electrode obtained by nailing or molding an electrode having a small diameter part and a large diameter part, a copper layer is coated by a method of fitting a copper pipe, and then a wire drawing process is performed. A method for manufacturing a DHD type glass-sealed diode electrode, which comprises cutting the obtained iron-nickel wire, nailing or forming the wire, and then forming a cuprous oxide film on the copper layer on the electrode surface.