JPH08255732A - Aging method for electronic component - Google Patents

Abstract

PURPOSE: To prevent an electronic component from being burnt, to reduce the pitch of the components and to deal with the mass production by aging the component in a thermostatic oven while supplying a current which does not cause ignition or smoking to the component. CONSTITUTION: Electronic components 14 on a lead frame 12 are connected to a power source circuit 16, current limiting elements 18 of the number corresponding to the number of the components 14 are aligned with the power source circuit 16, and connected to the components 14. The elements 18 are provided in the power source circuit 16, and aged in a thermostatic oven while supplying current which does not cause ignition or smoking to the component even if a short-circuit failure occurs. Thus, since the component is not burnt, it is not necessary to leave a gap to insert a separator, the pitch of the components can be set small, thereby sufficiently dealing with mass production.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aging method for removing defective products (initial defective products) that occur in the initial stage of the manufacturing process of electronic parts such as tantalum capacitors.

[0002]

2. Description of the Related Art Capacitors, resistors, coils, switches,
In the manufacturing process of electronic parts such as variable resistors and crystal oscillators, some defective products are unavoidable and need to be removed.

For example, taking a tantalum capacitor as an example, it is manufactured as a product through the following manufacturing steps. Tantalum powder is molded and sintered to produce a tantalum element with a lead wire. The Teflon (registered trademark) ring is pushed into the root of the lead wire and the tantalum element is welded to the carrier bar.

Dielectric oxide film (Ta ₂ O ₅ ) on tantalum element
Are formed electrochemically. Semiconductor processing of tantalum element. That is, the tantalum element is impregnated with a manganese nitrate aqueous solution and fired in a pyrolysis furnace. This impregnation and firing are repeated 5 to 10 times, and then the negative electrode side is silvered. The conductive paste is potted on the lead frame, the tantalum element cut from the carrier bar is placed on the conductive paste, and the wire tip (plus electrode side) is welded to the lead frame. Build.

After the conductive paste is solidified in a thermostat, the tantalum element is covered with epoxy resin to form a package (hereinafter referred to as a capacitor). After marking a predetermined symbol on the surface of the package, cut the tie bar. The so-called aging is performed by exposing it to a constant temperature oven for a long time and applying a predetermined voltage.

Characteristic inspection is performed and defective products (initial defective products)
Is cut and removed from the lead frame. (10) Cut the capacitor from the lead frame, bend and form the lead terminal into a predetermined shape, and then perform the final inspection (characteristic inspection,
(Shape inspection) removes defective products and carries only good products
The final product (tantalum capacitor) is housed in a cup.

The above aging is carried out for the purpose of revealing defective products at an early stage. In this aging, a constant temperature furnace is used as an aging device and a constant temperature of about 125 ° C. is used. The condenser circulates in the furnace for approximately 2 hours.

Defective product at the initial stage of manufacturing (initial defective product)
It is known that most (90-95%) of these are electrical short circuits, and this defective product can be easily burned when a sufficient current is applied. Utilizing this fact, the aging of the large current combustion method, which is highly economical in terms of mechanical devices, that is, a method of burning and removing a defective product that is about to cause a short circuit with a large current is widely adopted.

According to the combustion by the large current, the initial defective product itself is extinguished and removed by the combustion, and the initial defective product (initial defective product) is revealed during the aging. for that reason,
The characteristic inspection of 1 is sufficient if it detects a defective product having a quality different from that of a short circuit.

[0010]

If the spacing between the capacitors in the lead frame, that is, the pitch of the lead frames, is reduced, the capacitors are mounted densely on the lead frame, and the production efficiency is improved. It is preferable in terms of mass productivity.

By the way, when a large current is supplied to burn a capacitor, the temperature thereof reaches 600 to 800 ° C. and the adjacent non-defective product is abnormally heated. Therefore, the non-defective capacitor is often short-circuited in a chain. Induces combustion. Therefore, comb-shaped separators are arranged side by side on the lead frame, the comb tips are inserted in the gaps between the capacitors, and the capacitors are separated from each other, and then the capacitors are burned.

In this method, it is necessary to leave a gap into which the separator is inserted, and the pitch of the lead frame is limited. At present, the pitch of about 4.5 to 5.0 mm is the minimum, which is no longer the limit. Has been done. However, the pitch
Even if the production efficiency is improved to 4.5 to 5.0 mm, further mass production has recently been desired, and this method cannot be used anymore.

Further, although the adverse effect at the time of combustion is prevented by the separator, burning dust is scattered and contaminated by the jigs of the lead frame, the separator, and the constant temperature furnace, so that the cleaning is performed. Is required. When burning, the capacitor is 600
Since it reaches a high temperature of ~ 800 ° C, the separator and jig are severely damaged.

Further, a large current, for example, a current of 10 A is supplied for burning, but a peak current much larger than this is momentarily supplied as a pulse current. Although this pulse current flows for an extremely short time, it is extremely harmful especially to electronic components such as tantalum capacitors that are vulnerable to pulse current, and often has a bad effect such as degrading the characteristics of non-defective products. .

In the known aging method in which a large current is supplied to burn the initial defective product as described above, the pitch of the lead frame is limited, and mass production cannot be adequately supported. Due to the high temperature during combustion, non-defective products also become defective products, and jigs and separators are significantly damaged. A pulse current far exceeding the set current flows, which adversely affects the characteristics. There is a drawback called ----.

It is an object of the present invention to provide an aging method for electronic parts which can sufficiently cope with mass production without adversely affecting characteristics.

[0017]

In order to achieve this object, according to the present invention, a minute current that does not cause ignition or smoke generation, for example, a current limit such as a constant current diode in a power supply circuit of an electronic component is provided. The electronic components are aged in a constant temperature oven while a current is applied to the electronic components by limiting the maximum current to 100 μA.

[0018]

In this method, since electronic parts are not burned,
There is no need to leave a gap into which a separator can be inserted, the pitch of electronic components can be set small, and mass production can be fully supported. Needless to say, a separator for isolating electronic parts is not required.

Further, since it does not burn, there is no stain due to the scattering of burnt debris, cleaning is unnecessary, and
Damage to the lead frame jig is also prevented.

Furthermore, no harmful pulse current flows and no adverse effect is exerted on the characteristics.

[0021]

Embodiments of the present invention will now be described in detail with reference to the drawings.

According to the present invention, the aging is performed in the constant temperature furnace while applying a current that does not cause ignition or smoke even if a short circuit occurs to the electronic components.

For example, as shown in FIG.
An electronic component on the system 12, for example, a tantalum capacitor 14 is connected to a power supply circuit 16, and in the power supply circuit, a number of current limiting elements 18 corresponding to the number of tantalum capacitors are arranged in parallel and connected to the tantalum capacitor. A limited value current is flowing through the tantalum capacitor. Current limiting element 18
For example, a constant current diode is used.

According to the experiment, for the tantalum capacitor 14 of 10V-100 μF, the maximum value of the flowing current is 10 μA, 100
Leakage current after aging when limited to μA and 1000 μA
(LC) showed a distribution as shown in FIG.

Before aging, the leakage current of the 1000 tantalum capacitors 14 is only 2 μA even at its upper limit value, which is far below the standard value (LC.Spec., 10 μA).

Here, if the tantalum capacitor 14 which is about to reach the initial failure (short circuit) is completely over the leakage current standard value (10 μA) after aging, the initial failure becomes apparent. As a result, it can be removed as a defective characteristic.

For example, a maximum current of 10 μA was passed during aging which circulates in a constant temperature furnace for 2 hours, and it is taken out from the constant temperature furnace and the characteristics are inspected.
The leakage current of 14 is the other one on the borderline of the standard value.
One was measured just below the borderline. And the median Nmed. Increased only slightly from the value before aging.

When the maximum current is set to 100 μA, the leakage currents of the three tantalum capacitors 14 completely exceed the standard values.
However, the manifestation of initial defects (initial defective products) was recognized.

Further, when the maximum current was set to 1000 μA, similarly, the leakage currents of the three tantalum capacitors 14 completely exceeded the standard values.

At both the maximum current of 100 μA and the maximum current of 1000 μA, three completely leak current standard values are revealed and can be recognized as initial defective products.

The maximum current is 10 μA, 100 μA, 1000 μA
The median Nmed. Did not change in any of the.
From this, it can be understood that the three values near the upper limit in the case of 100 μA and 1000 μA are abnormal values, and most of the tantalum capacitors 14 are normal values far below the standard value as in the case of the maximum current of 10 μA. .

From the results of this experiment, in the 10V-100 μF tantalum capacitor 14, when the maximum current value is 10 μA, the initial failure (initial failure product) cannot be revealed.
It can be seen that it can be realized with μA.

The currents (maximum currents, limiting currents) added for manifesting the initial failure naturally vary depending on the type and rating of electronic parts. As shown by hatching in FIG. 3, the maximum current is sufficient if it is a value that does not cause ignition or smoke and that reveals an initial failure. Here, since the smoke is usually emitted before ignition, it is not necessary to consider the ignition characteristics.For a tantalum capacitor 14 of 10V-100 μF, a value larger than 100 μA and smaller than the smoke characteristics is selected as the maximum current. Be done.

For example, when a current is supplied to the 10V-100 μF tantalum capacitor 14 using a constant voltage power source set to 10V-1A, as shown in FIG.
A pulse current of 16.4A flows. On the other hand, a constant current diode is used as the current limiting element 18 in its current supply circuit 16
When it is installed in the device, a current limited to a maximum of 500 μA flows only as shown in Fig. 4 (B). In this way, by limiting the maximum current, harmful pulse current does not flow and characteristics are not deteriorated.

The maximum current varies depending on the type and rating of electronic parts, and it is preferable to select the maximum current depending on the type and rating of electronic parts. However, it is realistic and practical to reveal the initial failure under a common maximum current with general versatility.For example, in the tantalum capacitor 14, if the maximum current is 500 μA, 10V-10
It was confirmed by experiments that initial defects can be revealed even in many tantalum capacitors other than 0 μF.

Although the case of the tantalum capacitor 14 as an electronic component has been described, it goes without saying that the present invention can be applied not only to the tantalum capacitor but also to other capacitors, resistors, coils, switches, variable resistors, crystal oscillators and the like. Nor.

The above-described embodiments are intended to explain the present invention, and do not limit the present invention at all, and all modifications and alterations made within the technical scope of the present invention are also included in the present invention. It goes without saying that it will be done.

[0038]

As described above, according to the present invention, the electric current that does not cause ignition or smoke is merely applied to the electronic parts, and the electronic parts are not burned. Therefore, it is necessary to leave a gap into which the separator can be inserted. , The pitch of electronic parts can be reduced,
Sufficient for mass production. For example, in the conventional combustion method, the pitch of tantalum capacitors was limited to 4.5 to 5.0 mm, but according to the present invention, a pitch of 2.5 mm is also possible, and mass production of 1.8 to 2.0 times is possible compared with the conventional method. Becomes Needless to say, a separator for isolating electronic parts is not required.

Further, since no combustion occurs, the high temperature during combustion does not cause short-circuiting of non-defective products to make them defective or damage the jig of the lead frame. In addition, there is no stain due to the scattering of burnt residue, and cleaning is unnecessary.

Further, since the maximum current is limited by the power supply circuit, no harmful pulse current flows and no adverse effect is exerted on the characteristics.

[Brief description of drawings]

FIG. 1 is a principle diagram of an electronic component aging method according to the present invention.

FIG. 2 is a chart showing the distribution of leakage current of a 10V-100 μF tantalum capacitor after aging when the maximum current value is limited to 10 μA, 100 μA, and 1000 μA.

FIG. 3 is a chart showing ignition and smoke characteristics of a tantalum capacitor (electronic component).

FIG. 4 is a current waveform diagram in a case without a current limiting element and a case with a current limiting element.

[Explanation of symbols]

 12 Lead frame 14 Electronic parts (tantalum capacitor) 16 Power supply circuit 18 Current limiting element

Claims (3)

[Claims] 1. An aging method for an electronic component, which is performed in a constant temperature furnace while applying a current that does not cause ignition or smoke to the electronic component. 2. A method of aging electronic parts in a constant temperature oven, characterized by causing a maximum current limited electric current which does not cause ignition or smoke to flow to the electronic parts to manifest an initial failure. Aging method for electronic parts. 3. An aging method for an electronic component, wherein a current limiting element is provided in a power supply circuit of the electronic component, and a limited current that does not cause ignition or smoke is passed as the maximum current to the electronic component and is performed in a constant temperature oven.