JPH02106949A - Method of sealing semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the generation of trouble such as a crack, etc., in the deposited glass of a stem when the stem and a cap are sealed by increasing the inside diameter of a welding electrode brought into contact with the stem by the specific times of an inside diameter brought into contact with glass of the stem when the stem and the outer edge section of the cap are resistance- welded. CONSTITUTION:When a semiconductor-element electrode and leads are connected and covered with a hollow hat type cap 7 and stems 4 and a cap outer edge section 7a are held by metallic cylindrical type welding electrodes 8, 9 having ring-shaped cross sections and resistance-welded, the inside diameters of the welding electrodes 8, 9 brought into contact with the stems 4 are increased by the 1.08-1.12 times of the inside diameters of sections brought into contact with deposited glass 2 of the stems 4. That is, when the stems 4 and the cap 7 are resistance-welded, the stems 4 are placed on the lower welding electrode 7 and the upper section of the cap 7 is covered with the upper welding electrode 9, and arranged between the upper and lower platens 10a, 10b of a welder, and the platens are pressured and the stems 4 and the cap 7 are resistance- welded after energization.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a system and a method for sealing a cap in the assembly process of a hat-shaped can case type signal transistor, FET, thyristor, etc.

[Conventional technology]

Conventionally, in this type of hat-shaped can case semiconductor device, as shown in FIG. 1, a plurality of metal leads 3a, 3b, and 3c having circular cross sections are embedded inside a thin iron-based metal plate 1 formed into a hat shape using fused glass. 2, this thin metal plate l
A semiconductor element 5 is soldered to the top surface of a stem 4 which is electrically insulated from the electrodes of the semiconductor element 5 and leads 3a, 3.
After bonding with thin metal wires 6a and 6b made of Au, A6, etc. by ultrasonic welding, etc., the hollow hat-shaped cap 7 is covered, and the platen of a DC or AC welding machine is sandwiched between highly conductive welding electrodes 8 and 9. After being pressurized by 10a and 10b and energized, resistance welding is performed. However, although FIG. 3 is an enlarged view of the welded part, the inner diameter D2 of the lower electrode 8 is smaller than the thin metal plate 1 of the stem 7.
smaller than the inner diameter d in contact with the glass.

[Problem to be solved by the invention]

In the conventional hat-shaped can case semiconductor device described above,
The outer edge of the thin metal plate 1 of the stem due to the current applied during resistance welding.
After a and the cap outer edge 7a are melted and welded to each other, pressure is applied, and there is a drawback that glass cracks 11 are more likely to occur at the boundary between the welded glass 2 and the stem metal thin plate l.

[Means to solve the problem]

In the method for sealing a hat-shaped can case semiconductor device according to the present invention, the inner diameter D1 of the welding electrode 8 in contact with the stem 1 during sealing is 1.08 to 1.08 of the inner diameter d of the stem in contact with the glass 2.
It is 1.12 times.

That is, according to the present invention, a thin metal plate is formed into a hat shape, and a plurality of leads with a circular cross section are electrically insulated from the thin metal plate by a welded glass buried inside the hat through a plurality of holes in the top surface of the hat. A semiconductor element is forged on the top surface of the stem of the structure, and after bonding the semiconductor element electrode and lead with a thin metal wire by ultrasonic welding or the like, a hollow hat-shaped cap is covered, and the stem and the outer edge of the cap are welded with a ring-shaped metal cross section. A method for sealing a semiconductor device, characterized in that the inner diameter of the welding electrode in contact with the stem is 1.08 to 1.12 times the inner diameter of the stem in contact with glass when performing resistance welding by sandwiching between cylindrical welding electrodes. get.

According to the present invention, glass cracks can be prevented by appropriately selecting the inner diameter of the welding electrode that contacts the stem during sealing, without changing the configuration of the semiconductor device at all.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which a thin metal plate 1, a welded glass 2. Metal leads 3a, 3b.

3c, a stem 4 and a semiconductor element 5. thin metal wire 6a,
6b and a cap 7, the semiconductor device has exactly the same structure as the conventional one.

However, when resistance welding the stem 4 to the cap 7, the stem 4 is placed on the lower welding electrode 8, the upper welding electrode 9 is placed over the cap 7, and the welding machine (not shown) is placed between the upper and lower platens 10a and 10b. After applying pressure to the platen and energizing, the stem 4 and the cap 7 are resistance welded. FIG. 2 shows a stem 4 according to the present invention. It shows the positional relationship between the cap 7 and the lower electrode 8 when they are sealed.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to prevent defects such as cracks or cracks in the welded glass of the stem when sealing the stem and the cap in the assembly process of a knot-type can case semiconductor device. , has high economic effect.

...Thin metal wire, 7...Cap, 7a...
...Outer edge of cap, 8...Lower welding electrode,
9... Upper welding electrode, 10a, 10b...
...Welding machine platen, 11...Crack.

Agent: Patent Attorney Susumu Uchihara

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
FIG. 3 is an enlarged sectional view of the welded portion of the conventional embodiment.

Claims (1)

[Claims] A thin metal plate is formed into a hat shape, and a plurality of leads are passed through a plurality of holes on the top surface of the hat, and a semiconductor element is electrically insulated from the thin metal plate by a welded glass buried inside the hat. After soldering and connecting the semiconductor element electrode and the lead, a hollow hat-shaped cap is placed on the stem, and the outer edge of the cap is sandwiched between metal cylindrical welding electrodes having a ring-shaped cross section to perform resistance welding. The inner diameter of the welding electrode in contact with the stem is 1.08 to 1 of the inner diameter of the portion of the stem in contact with the welded glass.
．． A method for sealing a semiconductor device characterized by 12 times