JPS599230B2 - How to clean the insulator surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a marking method for resin-sealed electronic components that can clearly mark various marks on the surface of the resin-sealed outer shell of the resin-sealed electronic component. be.

Generally, insulators tend to become electrically charged due to friction between the insulators or friction with other objects, and when this becomes electrically charged, a large amount of dust existing around the insulator adheres to the surface of the insulator. .

In this way, even if a large amount of dust adheres to the insulator surface, this usually does not cause a problem, but if the object to be marked is a relatively small resin-sealed electronic part, It has been found that the mark to be applied is also small, and the clarity of the mark is impaired by dust adhering to the surface of the resin, which is easily charged. In recent years, many electronic components encapsulated with synthetic resin have appeared, and it is necessary to attach small marks such as the product name, date of manufacture, or company name to these as well. By the way, cloth-like bodies made of polyethylene resin, styrene resin, or vinyl resin, which are often used as synthetic resin bodies, as well as resin molded bodies formed by molding epoxy resin, are particularly susceptible to electrostatic charge, and are particularly prone to being used in dry environments. This phenomenon is further exacerbated at the bottom.

Due to this phenomenon, a large amount of dust adheres to the surface of resin-sealed electronic components sealed with a synthetic resin body, and when a mark is placed on such a surface, for example, marking ink and The mark may become unclear due to direct contact with the product surface, or the mark may also peel off as dust peels off after marking has been done, i.e. dust cannot be removed. If a mark is applied to a sufficient surface, the mark will not be defective in the initial state, but as time passes, problems such as peeling of the mark will occur. In recent years, the shape of resin-sealed electronic components has tended to become smaller, and the marks attached thereto have also tended to become smaller, making the above-mentioned disadvantages more pronounced. In view of these inconveniences, a marking method has already been proposed in which the surface of a resin-sealed electronic component, which is easily charged, is covered with an antistatic film and then a mark is attached thereto.

However, this method requires a step to form an antistatic film, which increases the product cost, or marks are actually placed on the antistatic film, so if the antistatic film peels off, At the same time, problems such as peeling off of marks still remain. The present invention can eliminate all inconveniences in the marking method of forming such an antistatic film and then applying a mark, and moreover, it is possible to easily check the condition of the surface to be marked to be clean and dust-free. This paper proposes a marking method that introduces a cleaning treatment that can be used to determine the condition of the electronic component.By exposing the surface of the resin-sealed electronic component to be marked to an alternating current corona discharge, electrical charges are generated in the sealing resin. The surface to be marked is then prepared by blowing gas onto the surface at the same time or immediately after exposure to the alternating current corona discharge to scatter any dust adhering to the surface. The symptoms of hemorrhoids according to the present invention include cleaning and then applying mata.

The present invention will be described below using as an example a marking method for a resin-sealed semiconductor device to which the method of the present invention is applied. The figure shows a marking device for resin-sealed semiconductor devices. In the figure, a resin-sealed semiconductor device indicated by 1 is transported on a grounded metal rail 2, and a marking roller 3 places necessary marks on the upper surface of the resin-sealed semiconductor device. It has a structure in which marks are attached.

However, most of these resin-sealed semiconductor devices are electrically charged when they are handled from the time the resin molding is completed until the marking process, and there is a considerable amount of dust on the surface that is difficult to remove. It's attached. In order to remove such dust and clean the surface before marking, a cleaning process consisting of neutralizing the electrical charge by alternating current corona discharge and blowing gas is performed. That is, the surface is cleaned by a cleaning device comprising a needle-shaped discharge electrode 4 and an air discharge tube 5 to which an AC high voltage is applied to generate an AC corona discharge. This cleaning device is disposed in front of the marking roller 3 and in a position where the resin-sealed semiconductor device being transferred can be exposed to alternating current corona discharge below. Therefore, even if the resin-sealed semiconductor device is electrically charged before being transported and has dust attached to its surface, the electrical charge is neutralized as it is exposed to corona discharge at the bottom of the cleaning device. As a result, the dust simply remains on the surface. In this way, if air is released from the air release tube 5 toward the surface of the resin-sealed semiconductor device at the same time as or immediately after the resin-sealed semiconductor device is exposed to AC corona discharge, the surface The dust on the surface is easily scattered, and the surface of the resin-sealed semiconductor device becomes a clean surface. Note that it is not preferable to leave the scattered dust as is, but it is preferable to exhaust it to other parts where the dust is allowed to exist using an exhaust device. If the resin-sealed semiconductor device exhibiting the surface condition thus cleaned is then transferred to the lower part of the marking roller 3 and marked thereon, it is possible to reliably make a clear mark. Note that the significance of using AC corona discharge as corona discharge is that the charges are reliably neutralized even if the battery is charged positively or negatively.

However, the neutralizing effect of AC corona discharge is smaller than that of DC corona discharge. Therefore, if necessary, the number of cleaning devices used may be increased to compensate for the lack of neutralizing effect. In the illustrated example, three cleaning devices are arranged. Next, an example will be described in which the method of the present invention is applied to a resin-sealed power 1C.

Marks with a line width of 0.2 to 0.3 mm were given to the same 1C (approximately 100,000 pieces), and when even a part of the mark was chipped (non-adhesive), it was considered to be defective. Conditions: AC corona discharge treatment (A
C3KV~6KV) Air blowing treatment (pressure 1K'/C
T! L2) Defective rate: 0.1% On the other hand, in the case of the conventional method in which no treatment was performed, the defective rate reached as high as 4 to 5%.

As described above, the mark defect rate was significantly reduced by the method of the present invention. Above, the case where the present invention is applied to marking of resin-sealed semiconductor devices has been explained as an example.
The method of the present invention can be widely applied to the marking of other resin-sealed electronic components that require cleaning the surface by removing dust that adheres to the surface of the insulator when it is charged. be. As is clear from the above explanation, according to the method for marking resin-sealed electronic components according to the present invention, dust attached to the surface to be marked due to charging can be removed without adding any special work steps. It can be removed to clean this surface and significantly reduce mark defects, eliminating the inconveniences of the conventional method of forming an antistatic film, offering greater workability compared to the conventional method, and making it easier to automate marking work. This is an extremely industrially meaningful method.

BRIEF DESCRIPTION OF THE DRAWINGS The figure shows a marking device for a resin-sealed semiconductor device that has a surface cleaning effect that enables the marking method according to the present invention.゛1...Resin-sealed semiconductor device, 2...
・Metal rail, 3...Marking roller, 4・
...Acicular discharge electrode for generating AC corona discharge, 5.
...Air release pipe.

Claims (1)

[Claims] 1 Prior to marking, at least the marking surface of the resin-sealed electronic component is exposed to alternating current corona discharge to neutralize the electrical charges in the sealing resin, and further, the marking surface is exposed to alternating current corona discharge. At the same time or immediately after being exposed to the electric discharge, a gas is blown toward the mark-bearing surface to scatter dust adhering to the surface, cleaning the mark-bearing surface, and then marking the mark-bearing surface with a specified mark. A method for marking resin-sealed electronic components.