JPS6034811B2 - Manufacturing method for resin-sealed semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a resin-sealed semiconductor device, and particularly to a method of removing resin burrs formed on a lead frame during resin-sealing.

Traditionally, resin-encapsulated semiconductor devices have been produced by cutting a metal plate by etching or pressing to form a lead frame, mounting the element on the element mounting part of the lead frame, and connecting the lead terminals and element electrodes of the IJ board frame with thin metal wires. After connection, the lead frame has been manufactured by molding and sealing the resin using a molding die and cutting off unnecessary portions of the lead frame.

When molding and sealing the semiconductor element and the peripheral part of the semiconductor element in the above manufacturing method, the external IJ clamped by the mold
The resin that has leaked into the board forms a film, often resulting in so-called resin burrs. In order to remove this burr, mechanical means such as sandblasting have been used, but this method has disadvantages such as deformation of the lead and damage to the lead surface. In addition, a film that can be easily etched is provided in advance on the lead portion where resin burrs adhere, and after molding and sealing,
A method has been used to remove resin burrs by etching the coating.

However, the above-mentioned method has the disadvantage that a step of forming a coating must be provided in advance, which increases the manufacturing cost. An object of the present invention is to provide a method for easily removing resin burrs while eliminating these drawbacks. That is, in the present invention, after completing resin molding and sealing, electricity is applied in an electrolytic degreasing bath with the frame as an anode or a cathode, and the resin is degreased by the action of the degreaser and the action of oxygen or hydrogen gas generated from the frame. This method is characterized by peeling off and removing burrs from the lead frame. The method of the present invention will be explained below using examples.

[Example 1] Electrolytic degreasing agent containing 75% caustic soda and 1% surfactant; Bath solution concentration 100%; temperature 50oo
, electrolysis voltage 5V; current density (cathode) vessel/dm2: time 1
When resin molding and sealing was completed under the above conditions and the lead frame was electrolytically degreased, it was found that most of the thin resin burrs were broken in their adhesion to the lead frame.

[Example 2] When electrolytic degreasing was carried out under the same conditions as in Example 1 with the cathode and anode reversed, the effect was relatively inferior to that in Example 1.

Judging that this is because the oxygen gas generated at the anode is half the hydrogen gas generated at the cathode, we set the current density (anode) to 6 A/dm2, and obtained the same effect as [Example 1]. . [Example 3] Next, electrolytic degreasing was carried out using a steel ball as a media in an electrolytic barrel at a voltage that gave the same liquid composition, temperature, and current density as in Examples 1 and 2. The effect was even greater than 2.

This is thought to be due to the effect of the barrel crossing the ocean. In addition, we investigated the correlation between the deburring effect and the concentration, temperature, and current density, and found that although it saturates at about 150 m/s, the higher the concentration, the higher the temperature, and the higher the current density, the more effective the deburring effect becomes. was big. Also, commercially available alkaline electrolytic degreaser 3
When examining the burr effect due to electrolytic degreasing, it was found that the burr removal effect was similar to that of the example, although there were some differences.

Claims (1)

[Scope of Claims] 1. The resin-sealed lead frame is used as an anode or a cathode, and electricity is applied in an alkaline electrolytic degreasing bath, and the lead frame is formed by the action of the degreaser and the action of the gas generated from the lead frame. A method for manufacturing a resin-sealed semiconductor device, characterized by removing resin burrs. 2. The method for manufacturing a resin-sealed semiconductor device according to claim 1, characterized in that an electrolytic barrel is used during electrolytic degreasing.