JPH04121754U - Structure of lead frame for electronic components - Google Patents

Abstract

(57) [Summary] [Purpose] In the lead frame 10 for electronic components,
To enable a dam bar 14 for damming up molten synthetic resin when molding a mold part 15 to be easily punched out with light force without damaging lead terminals 13. [Structure] The lead terminal 13 of the dam bar 14
A slit 17 or a cut line extending along the longitudinal side edge of the lead terminal 13 is cut in a continuous portion of the dam bar 14, leaving continuous portions 18 and 19 at both left and right edges in the width direction of the dam bar 14.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is based on the semiconductor chip part of electronic components such as transistors and ICs. , when manufacturing electronic components packaged with thermosetting synthetic resin mold parts. This relates to improvements in the lead frames used.

0002

[Conventional technology]

Conventionally, the semiconductor chip part was packaged with a mold part made of thermosetting synthetic resin. The structure of the lead frame used when manufacturing electronic components is as follows. For example, as described in Japanese Patent Application Laid-Open No. 58-43552 and shown in FIGS. , the island portion 2 on which the semiconductor chip is mounted is integrally formed on the lead frame 1. At the same time, the plurality of lead terminals 3 extending toward the island portion 2 are integrated. A dam bar 4 is integrally formed between each lead terminal 3. When forming the synthetic resin mold part 5, the molten synthetic resin is Each dam bar 4 is used to dam the motor. After molding the lead portion 5, as shown by the two-dot chain line in FIGS. The punch 6 moves up and down toward the receiving blade (not shown) provided on the bottom side of the arm 1. Therefore, it is configured to be cut out by punching.

0003

[Problem that the idea aims to solve]

By the way, the width dimension W of the dam bar 4 between each of the lead terminals 3 is reduced. When forming the mold part, this dam bar 4 is pressed by the pressure of the molten synthetic resin. It will deform outwards and the molten plastic will leak out. Therefore, the width dimension W of the dam bar 4 between each lead terminal 3 should be adjusted to a certain degree. In other words, it is necessary to configure it as wide as possible. However, if the dam bar 4 is configured to have a wide dimension, the dam between the lead terminals 3 When punching and cutting the bar 4 with the punch 6, among the dam bars 4, A shearing action is applied to the continuous portion of the lead terminal 3 along the long side edge of the lead terminal 3. The force required for cutting increases, and therefore the punch 6 is moved up and down. The drive mechanism for the Since the dam bar 6 must be made larger, a device for punching and cutting the dam bar 6 is provided. However, the dam bar 4 is punched out by the punch 6. When removing the wire, be careful not to apply a large force to the lead terminal 3 as well. Therefore, there is a problem that the lead terminal 3 may be frequently damaged by deformation or the like. there were.

0004 The present invention punches out the dam bar between each lead terminal with a small force. The technical problem is to solve the above problem by making it possible to eliminate the problem.

[0005]

[Means to solve the problem]

In order to achieve this technical problem, the present invention was developed to package the package using a synthetic resin mold part. Connecting the lead terminals between multiple lead terminals for the semiconductor chip to be mounted. In a lead frame formed by molding a dam bar, the lead terminal of the dam bar is A slit or cut extending along the long side edge of the lead terminal The dam bar has a structure in which the dam bar is carved on both left and right edges in the width direction, leaving a continuous part. Ta.

[0006]

[Effect]

With this configuration, the dam bar has continuous parts on both left and right edges in the width direction. Since it is integrally connected to the lead terminal through the During shaping, it is possible to reliably hold back the molten synthetic resin. On the other hand, a portion of the dam bar that is continuous with the lead terminal is provided with a lead terminal. This is achieved by cutting a slit or cut line along the long side edge of the To prevent the dam bar from deforming outward due to the pressure of the molten plastic. In addition, even if the dam bar is configured to have a wide dimension, the dam bar is After molding, when punching and cutting with a punch, the punching and cutting The force required for this is reduced by the amount of slits or cut lines carved in the dam bar in advance. Therefore, the dam bar can be easily punched out with a light force.

[0007]

[Effect of the idea]

Therefore, according to the present invention, it is possible to completely stop the molten synthetic resin. Therefore, even if the dam bar is wide, the dam bar can be easily struck with a light force. Since the dam bar can be punched out and removed, the dam bar can be punched out and removed using a punch. It is possible to reduce the size of the device for the dam bar and reduce costs. This greatly reduces damage to lead terminals when punching out and cutting out lead terminals. This has the effect of improving quality.

[0008]

【Example】

Embodiments of the present invention will be described below with reference to the drawings (FIGS. 1 to 3). In the figure, reference numeral 10 indicates a lead frame made of a metal plate, and the lead frame 10, an island portion 12 for mounting a semiconductor chip 11 is integrally formed. and a plurality of lead terminals extending toward the island portion 12. 13 are integrally molded.

[0009] Also, the portion between each lead terminal 13 and the outermost portion of each lead terminal 13 are The lead terminal 13 located on the side and the side frame 20 in the lead frame 10 , 21, when molding the synthetic resin mold part 15, a molten synthetic resin is applied. Dam bars 14 for stopping are each integrally formed. Then, the lead terminals 13 on both sides of each dam bar 14 and both side walls are provided. Along the longitudinal side edge of the lead terminal 13 in a continuous portion with respect to the frames 20 and 21, The extending slits 17 are formed in continuous parts on both left and right edges of the tie bar 14 in the width direction. 18 and 19 (parts without slits) are carved.

0010 With this configuration, each dam bar 14 has a Connecting to the lead terminal 13 or both side frames 20 and 21 via the continuous parts 18 and 19 Since it is integrally continuous, when molding the synthetic resin mold part 15, Molten synthetic resin can be reliably dammed up. On the other hand, among the dam bars 14, the lead terminal 13 and the side frames 20, 2 1, there is a slit extending along the long side edge of the lead terminal 13. Since the groove 17 is carved, this dam bar 14 can resist the pressure of the molten synthetic resin. Therefore, in order to prevent outward deformation, each dam bar 14 has a wide dimension. Even if the dam bar 14 is configured as shown in FIG. As shown by the dashed line in FIGS. 2 and 3, the punch 16 punches the At this time, the force required for punching and cutting is determined by applying the slit 17 to the dam bar 14 in advance. Each dam bar 14 can be easily struck with a light force because the size is reduced by the amount of engraved. It can be removed and removed.

[0011] Note that in the above embodiment, each dam bar 14 has a Although the case where the extending slit 17 is carved has been shown, the present invention has a structure in which the slit 17 is carved. Instead, a cut line is formed extending along the longitudinal side edge of the lead terminal 13. Alternatively, each dam bar 14 may be punched out using a punch 16. In this case, first cut one continuous part 18, and then cut the other continuous part 19. By doing so, the force required for punching and cutting the dam bar 14 is further reduced. can do.

0012 Furthermore, when cutting out each dam bar 14, two points are shown in FIGS. 2 and 3. Using a punch 16' configured as shown by the chain line, this punch 16' In the synthetic resin burrs 15a formed between each dam bar 14 and the mold part 15, By configuring the punch 1 so that it does not come into contact with the burr 15a, the burr 15a causes the punch 1 to Since damage to the punch 6' can be prevented, the durability of the punch 16' is greatly improved. be able to.

[Brief explanation of drawings]

FIG. 1 is a plan view of a lead frame showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II in FIG. 1;

FIG. 3 is an enlarged perspective view showing the main parts of FIG. 1;

FIG. 4 is a plan view of a conventional lead frame.

FIG. 5 is an enlarged sectional view taken along the line V-V in FIG. 4;

6 is an enlarged perspective view showing the main part of FIG. 4. FIG.

[Explanation of symbols]

10 Lead frame 11 Semiconductor chip 12 Island part 13 Lead terminal 14 Dam Bar 15 Mold part 16,16' punch 17 slit 18,19 Continuous part

Claims (1)

[Scope of utility model registration request] Claim 1: Between a plurality of lead terminals for a semiconductor chip packaged in a synthetic resin mold part,
In a lead frame formed by modeling a dam bar that connects the dam bar, a slit or cut line extending along the longitudinal side edge of the lead terminal is formed in a portion of the dam bar that is continuous with the lead terminal in the width direction of the dam bar. The structure of a lead frame for electronic components is characterized by being engraved with continuous parts left on both left and right edges.