JPH06204568A - Lead frame terminal structure - Google Patents

Abstract

(57) [Summary] [Object] To provide a lead frame terminal structure suitable for a surface-mounted semiconductor element and capable of effectively enlarging its electrode portion. [Structure] A semiconductor chip is die-bonded to the tip of one lead frame 13, and a bonding wire 12 for connecting to the semiconductor chip is bonded to the tip of the other lead frame 11, so that each lead frame 1
Surface mounting is performed on the wiring board via the electrode portions 11a and 13a that are formed so as to project close to the bonding portions 1 and 13. The electrode portions 11a and 13a are enlarged to ensure a large contact area with the wiring board. Particularly, the lead frames 11 and 13 are formed from the ingot material by cutting or drawing with a die.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame terminal structure for a surface mount type semiconductor device mounted on a printed circuit board or the like.

[0002]

2. Description of the Related Art Conventionally, a surface mount type semiconductor element, for example, a surface mount type LED is constructed as shown in FIG.
In FIG. 3, the LED 1 has a projecting portion 2 protruding laterally.
lead frames 2 and 3 made of two conductive metal materials provided with a and 3a, and one of the lead frames 2 and 3,
For example, the LED chip 4 mounted on the enlarged upper end of the lead frame 3 and the protruding portions 2a, 3a are surrounded by a pedestal, and a resin mold is formed so that the upper portions of the protruding portions 2a, 3a are exposed. And a lens portion 6 formed by resin molding of transparent resin so as to surround the upper ends of the lead frames 2 and 3 and the LED chip 4 above the base portion 5. ing.

The LED chip 4 includes a lead frame 3
Is electrically connected to the upper end surface of the other lead frame 2 by wire bonding. The tips of the overhanging portions 2a and 3a of the lead frames 2 and 3 are connected to the base portion 5
By being exposed to the side surface of the printed circuit board, it can be used as an electrode portion when mounting the surface-mounted LED 1 on a printed circuit board or the like, and can be soldered to a conductive pattern or the like formed on the printed circuit board. There is.

FIG. 4 shows a terminal structure of the lead frames 2 and 3, which has a two-dimensional (planar) structure as shown. The LED chip 4 is one of the lead frames 3
Is die-bonded in the tray 7 provided to enhance the reflection effect at the upper end of the. In the case of forming such lead frames 2 and 3, as shown in FIG. 5, the ends of each of the longitudinal directions are connected via a support portion 8 and press working or the like is performed so that a plurality of pairs are continuous. It is formed.
Therefore, the plate thickness t of the press material 9 shown in FIG.
It becomes the width W of the electrode portion of D1 (see FIG. 3).

[0005]

However, since the conventional lead frame 2, 3 terminal structure is formed by pressing as described above, in particular, the width of the electrode portion of the LED 1, that is, the overhang portion 2a, 3a. W is uniquely determined by the plate thickness t of the press material 9. For this reason LE
There was a problem that the contact area of the electrode portion with respect to the printed board could not be increased during mounting of D1 and a contact failure was caused in soldering with the conductive pattern or the like of the printed board. Further, since the widths (plate thickness t) of the lead frames 2 and 3 themselves are narrow, it is difficult to form the structure of the upper ends of the lead frames 2 and 3 into a shape that can meet the purpose such as enhancing the reflection effect. there were.

In view of the above points, an object of the present invention is to provide a lead frame terminal structure which is particularly suitable for a surface mount semiconductor element and whose electrode portion can be effectively enlarged.

[0007]

In the lead frame terminal structure of the present invention, a semiconductor chip is die-bonded to the tip of one lead frame, and a bonding wire for connecting to the semiconductor chip is attached to the tip of the other lead frame. In a lead frame that is surface-mounted on a wiring board through an electrode portion that is bonded and protrudes in the vicinity of the bonding portion of each lead frame, the electrode portion is enlarged to form the wiring board. It is designed to secure a large contact area with.

The lead frame is formed from the ingot material by cutting or drawing with a die.

[0009]

According to the lead frame terminal structure of the present invention, a large contact area with the wiring board is ensured by enlarging and forming the electrode portion to be connected to the wiring board. Since the electrode portion is formed large in this way, reliable and stable electrical connection can be realized and contact failure or the like can be effectively prevented. In particular, the lead frame can be formed into a desired size and shape by cutting the ingot material by cutting or drawing with a die, and the electrode can be easily and effectively expanded. can do.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the lead frame terminal structure of the present invention will be described below with reference to FIGS. Figure 1
Shows the structure of the main part of the terminal structure of the lead frame of the present invention. Also in the present embodiment, the present invention is applied to the surface mount type LED, but in the figure, the bonding wire 12 for connecting to the LED chip is bonded to the upper end of one lead frame 11, and the other lead frame 13 is bonded.
The LED chip is die-bonded to the upper end of the.
Then, surface mounting is performed on the wiring board via the electrode portions 11a and 13a that are formed so as to project at positions close to the bonding portions of the lead frames 11 and 13. The electrode portions 11a and 13a are formed so as to project laterally.
It is formed to be larger than the above-mentioned bonding portion at the upper end of 13. That is, the conventional overhanging portion 2 shown in FIG.
It is set to be considerably wider than the width W of a and 3a. Further, a dish portion 14 is provided on the upper end of the lead frame 13 to enhance the reflection effect of the LED chip to be die-bonded.

According to the lead frame terminal structure of the present invention, since the width W of the electrode portions 11a and 13a is formed to be large, a large contact area with the wiring board on which the surface mount type LED is mounted can be secured. As a result, it is possible to reliably and stably perform soldering with the conductive pattern of the printed circuit board, etc., and it is possible to reliably prevent electrical contact and effectively prevent contact failure and the like.

Here, the case of forming the lead frames 11 and 13 will be described. An ingot material made of a conductive metal material having an appropriate width dimension is three-dimensionally NC processed by a shaving machine or drawn by a die. As a result, the lead frames 11 and 13 are
As shown in FIG. 2A, a plurality of pairs are formed in a connected state. In this case, in the ingot material 10 shown in FIG. 2B, the hatched portion is cut or drawn (see also FIG. 1), but the width W of the electrode portions 11a and 13a is reduced.
The cutting or drawing process is performed so as to secure

In the above case, the connected lead frame 1
It is preferable to integrally form the reinforcing portion 15 for facilitating the processing of the parts 1 and 13 and the support base 16 for convenience in the subsequent process. Further, the outer end surfaces of the electrode portions 11a and 13a can be adjusted to an appropriate size and processed by NC processing or a die type shape. Furthermore, the lead frames 11, 13
As shown in FIG. 1, the upper end portion (bonding portion) of the can be formed as an irregularly shaped terminal, which is extremely advantageous when forming the above-mentioned dish portion 14 and the like, and is effective for enhancing the reflection effect. It is effective.

The bonding wire 1 is attached to the upper ends of the lead frames 11 and 13 formed by connecting as described above.
2 or LED chip is bonded, and then a pair of lead frames 11, 1 provided with electrode parts 11a, 13a
3, the base portion is integrally formed by insert molding, and at the same time, the electrode portions 11a and 13a are exposed to the outside from the base portion.

Since the ingot material 10 made of a conductive metal material is used for three-dimensional cutting or drawing by a die as described above, the electrode portions 11a, 13a of the lead frames 11, 13 are formed. In particular, the contact area can be increased, and good electrical contact can be realized. In addition, it is easy to form the upper ends of the lead frames 11 and 13 as irregularly shaped terminals.
It becomes easy to form the plate portion 14 provided on the
It is possible to increase the light amount of the surface mount LED.

In the above embodiment, an example in which one lead frame 11 or 13 is formed in the X direction of FIG. 2 has been described, but by further increasing the width dimension of the ingot material 10, the X direction and the Y direction can be increased. It is possible to form the lead frames 11 and 13 in multiple directions, and to effectively realize a large number of lead frames.

[0017]

As described above, according to the terminal structure of the lead frame of the present invention, the electrode portion can be enlarged to secure a wide contact area with the wiring board, and reliable and stable electrical connection can be achieved. And it is possible to effectively prevent contact failure and the like. Further, there are advantages such as being able to realize a surface mount type semiconductor element having high reliability and excellent performance.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part according to an embodiment of a lead frame terminal structure of the present invention.

2A and 2B show a manufacturing process of a lead frame relating to a lead frame terminal structure of the present invention, FIG. 2A is a perspective view, and FIG.
Is a side view.

FIG. 3 is a perspective view of a conventional surface mount semiconductor device.

FIG. 4 is a perspective view of an essential part of a lead frame of a conventional surface mount semiconductor device.

FIG. 5 is a perspective view showing a manufacturing process of a conventional lead frame.

[Explanation of symbols]

 10 Ingot Material 11 Lead Frame 11a Electrode 12 Bonding Wire 13 Lead Frame 13a Electrode 14 Plate 15 Reinforcement 16 Support

Claims (1)

[Claims] 1. A semiconductor chip is die-bonded to the tip of one lead frame, and a bonding wire for connecting to the semiconductor chip is bonded to the tip of the other lead frame so as to project to a position close to the bonding portion of each lead frame. In a lead frame that is to be surface-mounted on a wiring board through the formed electrode part, the lead frame is formed by cutting or drawing with an ingot material, and the electrode part is enlarged. The lead frame terminal structure is characterized in that it is formed to secure a wide contact area with the wiring board.