JPH01243568A - Manufacture of electronic component and lead frame to be used for it - Google Patents

Abstract

PURPOSE:To reduce that a resin remains stuck to a lead by a method wherein a resin burr is pressed from a long side to a short side in a cross-sectional shape of a nearly trapezoid of the lead so that the resin burr can be easily dropped. CONSTITUTION:In an electronic component 20 which has been taken out from a metal mold after a resin sealing operation, resin burrs 17 are formed in a region surrounded by a lead 11, a dam part 16 of a lead frame and a resin- sealed part 18. The burrs 17 are formed in a cross-sectional shape of a nearly trapezoid which is opposite to a cross-sectional shape of a nearly trapezoid of the lead 11. A burr-dropping punch 21 with protruding parts 22 is situated in a corresponding position where the burrs 17 have been formed. By this setup, the burrs 17 can be easily dropped from the lead 11; it can be reduced that a resin remains stuck to the lead 11.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for manufacturing electronic components and a structure of a lead frame for electronic components, and is effective when used in manufacturing electronic components by resin sealing. related to technology.

[Conventional technology]

When creating an electronic component by resin sealing, resin burrs are formed in a region surrounded by the resin sealing part of the semiconductor element, the leads, and the dam part of the lead frame. Since this resin burr is unnecessary for electronic parts, it was
As shown in Japanese Patent No. 0-180126, the dam part is cut together with a dam cutting punch or removed by honing or other processing.

[Problem to be solved by the invention]

In the prior art, no consideration was given at all to the cross-sectional shape of the leads for easily removing resin burrs formed during resin sealing.

Therefore, even if the resin burr is simply pressed and removed, the resin burr may not completely fall off the lead and may remain attached to the lead. The resin used for manufacturing electronic components usually contains fine fins made of 5102, etc., and if dam cutting is performed with such resin burrs remaining, the dam cutting die will wear out. This significantly shortens the life of the dam cutting die. Furthermore, during lead molding, lead dents and lead bending defects occur, which impairs the appearance of the electronic component.

The present invention has been made to solve the above-mentioned problems, and its first object is to provide a method for manufacturing electronic components that allows resin burrs to be easily removed from leads. In addition, our second objective is to provide a lead frame from which resin burrs can be easily removed during the manufacture of electronic components.
The purpose of

[Means to solve the problem]

The first purpose is to resin-seal a lead having a substantially trapezoidal cross-sectional shape, and remove resin burrs formed adjacent to the lead during resin sealing from the long side of the substantially trapezoidal cross-sectional shape of the lead. This is achieved by pressing from the side toward the short side.

Further, the purpose of M2 is achieved by making the cross-sectional shape of the lead substantially trapezoidal.

[For production]

According to the above-described method of manufacturing an electronic component of the present invention, the resin burr formed adjacent to the lead during resin sealing is opposite to the cross-sectional shape of the lead because the cross-sectional shape of the lead is approximately trapezoidal. It is formed to have a substantially trapezoidal cross-sectional shape. Then, the resin burr is pressed against the resin burr in a direction from the long side to the short side of the approximately trapezoidal cross-sectional shape of the lead. That is, the resin burr is pressed from the short side to the long side of the substantially trapezoidal cross-sectional shape. Since the resin burr has a cross-sectional shape that widens toward the end in the pressing direction, a force acts at the interface between the lead and the resin burr in the direction of separating the resin burr from the lead, making it easy to remove the resin burr. be able to.

〔Example〕

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a semiconductor device manufactured by applying the electronic component manufacturing method of the present invention, and resin burrs formed during resin sealing have been removed. The cross-sectional shape of the lead 1 is similar to that of the semiconductor device 2 in FIG.
As is clear from FIG. 2, which shows the AA' cross section, it has a substantially trapezoidal shape.

The method of manufacturing an electronic component according to the present invention will be explained below with reference to FIGS. 3 to 8. First, a lead frame IO shown in FIG. 3 is prepared. This lead frame is a lead frame (tableless lead frame) that has a structure in which the semiconductor element is placed on the leads 11 instead of providing a tab on which the semiconductor element is placed. The cross-sectional shape is approximately trapezoidal, as shown in FIG. 4, which shows the BB' cross section.

Next, as shown in FIG. 5, a semiconductor element 13 is fixed onto the leads 11 of the lead frame 1° via an insulating sheet 12. Then, the electrode 1 formed on the semiconductor element 13
4 and the lead 11 are bonded using a wire bonding device. Next, resin sealing is performed using a well-known mold (not shown) so that the shape shown by the imaginary line 15 is obtained.

After resin sealing, the electronic component 20 taken out from the mold has a K6
(a) As shown in the figure, a resin burr 17 is formed in a region surrounded by the lead 11, the dam part 16 of the lead frame, and the resin sealing part 18. As shown in FIG. 66), the resin burr 17 is formed to have a substantially trapezoidal cross-sectional shape opposite to the substantially trapezoidal cross-sectional shape of the lead 11. As mentioned above, the resin burr is unnecessary for the appearance of the product, so the resin burr is removed.
a) As shown in the figure, position the burr removal punch 21 having a protrusion 22 corresponding to the position where the resin burr 17 is formed, and use the protrusion 22 of the burr removal punch 21 to remove the resin burr 17 in the direction of arrow G. Further, the pressing direction of the resin burr 17 will be explained in detail with reference to FIG. 7(b). As shown in FIG. 7(b), each of the protrusions 22 of the burr punch 21 is aligned with the position where the resin burr 17 is formed, from the long side to the short side of the approximately trapezoidal cross-sectional shape of the lead 11. It is lowered to the side and presses the resin burr 17. That is, in the cross-sectional shape of the resin burr 17, the resin burr 17 is pressed from the short side to the long side of a substantially trapezoidal shape. Therefore, by pressing the resin burr 17 in the direction in which its substantially trapezoidal cross-sectional shape widens toward the end, the resin burr 17 is formed at the interface between the lead 11 and the resin burr 17.
A force acts in the direction of separating the resin burrs 17 from the leads 11.
fall off from

After removing the resin burr 17, the lead frame 11 is removed.
The dam portion 16 is cut using a dam cutting punch (not shown). The electronic component after cutting is in the state shown in FIG. 8, and then the leads 11 are bent to form a predetermined shape, resulting in the electronic component shown in FIG.

As described above, according to the electronic component manufacturing method of the present invention, the resin burr is pressed from the long side to the short side of the approximately trapezoidal cross-sectional shape of the lead, so that the resin burr can easily fall off from the lead. Can be done.

Therefore, it is possible to reduce the amount of resin that remains on the lead during the resin burr removal process, and the StO contained in the resin can be reduced.
, etc. can reduce wear of the dam cutting die. Furthermore, appearance defects such as lead dents and lead bending can be reduced when the leads are bent.

In this embodiment, the cross-sectional shape of the lead is approximately trapezoidal, but by further making the cross-sectional shape of the dam portion approximately trapezoidal, resin burrs can be more easily removed.

Further, by forming a mark indicating the pressing force direction of the resin burr on either side of the lead frame, electronic components can be manufactured reliably without causing any operational inconvenience. Further, the pressing of the resin burr is not limited to a burr removal punch, and may be performed by deflashing or other processing.

Next, an example of a method for manufacturing a lead having a substantially trapezoidal cross-sectional shape in a lead frame used in the present invention is shown in FIGS.
This will be explained using Figure 1. As shown in FIG. 9, resist 21 is applied to the front and back curves of the metal plate 200 that will become the lead frame. Next, as shown in FIG. The unnecessary portions of the metal plate 20 are removed using a sixth-stage etching solution to remove the resist portions, thereby forming the leads 22 having a substantially trapezoidal cross-sectional shape. The angle θ between the substantially trapezoidal oblique side 23 that is the cross-sectional shape of the lead 22 and the imaginary line in the thickness direction of the lead frame is desirably 5 to 3 to 10 degrees. The degree θ is the drawing taper α (see Figure 12), which is formed in order to make it easier to take out electronic components from the mold after being molded.
This value corresponds to Further, the approximately trapezoidal cross-sectional shape of the lead may be any shape that facilitates the removal of resin burrs, and may have the structure shown in FIGS. 13 and 14.
By using the lead frame formed as described above, it is possible to provide a method of manufacturing an electronic component in which resin burrs can be easily removed.

〔Effect of the invention〕

A brief explanation of the effects obtained by the invention disclosed in this application is as follows.

Since the resin burr is pressed from the long side to the short side of the approximately trapezoidal cross-sectional shape of the lead, the resin burr can be easily removed from the lead. Therefore, it is possible to reduce the amount of resin remaining on the lead in the resin burr removal process, reduce wear on the dam cutting die, and extend the life of the dam cutting die. Furthermore, appearance defects such as lead dents and lead bending can be reduced when the leads are bent. Also,
By using a lead frame having leads having a substantially trapezoidal cross-sectional shape, the method for manufacturing an electronic component of the present invention can be carried out.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a semiconductor device produced by the method for manufacturing electronic components of the present invention, FIG. 2 is an enlarged view of the AA' cross section of the semiconductor device shown in Figure 1, and FIG. A schematic diagram of a lead frame used for manufacturing parts; 4th is an enlarged view of the BB' cross section of the lead frame shown in FIG. 3;
In the figure, a semiconductor element is mounted on a lead frame shown in No. 3.
i! 5(a) and 5(b) are schematic diagrams of the semiconductor device shown in FIG. 5 immediately after resin molding;
(b) is a schematic diagram showing the state in which the resin burr formed by the resin mold is pressed with a deburr punch, Figure 8 is a schematic diagram of the dam part of the lead frame cut away, and Figure 9 is a schematic diagram of the state in which the dam part of the lead frame is cut. Schematic diagram of the state in which resist is applied to the plate,
Figure 1O is a schematic diagram showing the state where the resist applied to the metal plate shown in Figure 9 has been partially removed, and Figure 11 is a schematic diagram showing the state where the resist applied to the metal plate shown in Figure 9 has been partially removed.
A schematic diagram showing the cross-sectional shape of a lead of a lead frame formed by etching the metal plate shown in Figure 0;
Figure 12 is a schematic diagram of a mold used for manufacturing electronic components.
3 and 14 are schematic diagrams showing cross-sectional shapes of lead frames according to other embodiments of the present invention. 1.11...Lead, 2...Semiconductor device, 10...
・Lead frame, 12...M5 edge sheet, 13...
- Semiconductor element, 14... Electrode, 15... Resin mold part virtual -117... Resin burr. Agent: Patent Attorney Katsuo Ogawa, -\No. 1
Figure A' Figure 2 Figure 3 Figure 5/a Figure 6 (tL) Figure 6 (b) Figure 1/ // Figure 7 (a-> Figure 7 (b) Figure 8 Figure 9 Figure 10 Figure 11 Figure 13

Claims (1)

[Claims] 1. In a method of manufacturing an electronic component, a lead having a substantially trapezoidal cross-sectional shape is sealed with a resin, and a resin burr formed adjacent to the lead during the resin sealing is A method for manufacturing an electronic component, characterized by pressing from the long side to the short side of a substantially trapezoidal cross-sectional shape. 2. The method of manufacturing an electronic component according to claim 1, wherein the pressing of the resin burr is performed using a burr removing punch having a pressing part for pressing the resin burr. 3. In a method of manufacturing an electronic component, a lead having a substantially trapezoidal cross-sectional shape is sealed with a resin, and a resin burr formed around the lead is placed on the long side of the substantially trapezoidal cross-sectional shape. A method of manufacturing an electronic component, characterized in that the lead is dropped by pressing it in the direction of the short side, and then the dam part connecting the lead is cut, and the lead is molded into a desired shape. 4. The method of manufacturing an electronic component according to claim 3, wherein the pressing of the resin burr is performed using a burr removal punch having a pressing part for pressing the resin burr. 5. A lead frame characterized in that the cross-sectional shape of the leads is approximately trapezoidal.