JPH05326781A - Lead frame and semiconductor provided therewith - Google Patents

Abstract

PURPOSE:To enable a lead frame to absorb stress applied onto a semiconductor element when the semiconductor element is used as sandwiched in between two leads. CONSTITUTION:A semiconductor element 1 is bonded as pinched by the pinching parts 2a and 13a of leads 2 and 13. A hole 10 is bored in a part of the lead 13 so as to make the part where the hole 10 is bored smaller in bending strength than the other part of the lead 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame and a semiconductor device using the same, and more particularly to a lead frame suitable for a resin mold type semiconductor device and a semiconductor device using the same. .

[0002]

2. Description of the Related Art Generally, a semiconductor device is manufactured through a process such as die bonding and resin molding. A series of these processes is applied to a lead frame formed by punching or etching a thin metal plate. It is done against.

As an example of a conventional lead frame, FIG.
The lead frames disclosed in JP-A-2-33956 and JP-A-2-284436 are shown in FIG. The lead frame shown in the figure is used for manufacturing a two-terminal semiconductor device such as a diode. In order to obtain a semiconductor device, first, the sandwiching portion 2a or 3a formed at the tip of the lead 2 or 3 is
After the semiconductor element (not shown) is die-bonded, the holding portions 2a and 3a are separated along the broken line in the figure. Then, the side frames 50 and 60 are connected to the feed holes 55 and 65.
The sandwiching portion 2a is overlaid on the semiconductor element 1 by moving the sandwiching portion 2a.

Next, the bumps provided in advance on the semiconductor element are melted to solder the element and the sandwiching portion 2a. FIG. 6 is a perspective view showing the configuration of the main part at this time, and FIG. 7 is a side view thereof. A semiconductor device is obtained by molding the portion 4 shown by the one-dot chain line in FIG. 7 with resin and separating the leads 2 and 3 at predetermined positions.

[0005]

However, in the structure of the lead frame in which the semiconductor element is sandwiched by the two leads and the wireless bonding is performed as described above, when heat stress and / or mechanical stress is applied to the lead frame, Since there is no part that absorbs these stresses,
There are problems that the semiconductor element is destroyed and the bumps come off. The mechanical stress is, for example, a stress generated between the holding portions 2a and 3a and the semiconductor element 1 when the lead frame is clamped by a mold for resin molding. Further, the thermal stress means, for example, a stress caused by a difference in coefficient of thermal expansion between the semiconductor element and the lead frame when heating is performed during soldering.

The present invention has been made in view of these points, and an object of the present invention is to provide a lead frame capable of absorbing stress applied to a semiconductor element when the semiconductor element is sandwiched between two leads. .. Another object is to provide a semiconductor device using such a lead frame.

[0007]

In order to achieve the above object, the lead frame of the present invention has a plurality of leads extending from a side frame and is used in such a manner that a semiconductor element is sandwiched between two leads. At least a portion of at least one of the leads has a bending strength smaller than that of the other portions of the lead.

To achieve the above object, the semiconductor device of the present invention is characterized in that the portion of the lead frame having the small bending strength is molded with resin together with the semiconductor element.

[0009]

According to such a lead frame structure, even if the mechanical stress or the thermal stress occurs, the stress is transmitted to the semiconductor element because the stress is absorbed by the portion of the lead having a small bending strength. ..

Further, according to the structure of the semiconductor device as described above, since the portion of the lead having a small bending strength is molded with the resin, there is no reduction in the strength which causes a problem in use.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. The same parts as those of the conventional example shown in FIGS. 5 to 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 shows a semiconductor device 1 according to a first embodiment of the present invention.
FIG. 2 is a perspective view showing a state in which is mounted, and FIG. 2 is a plan view showing a main part structure before die bonding in the manufacturing process of this embodiment. As shown in FIGS. 1 and 2, this embodiment has the same structure as that of the conventional example (FIGS. 5 to 7) except that a hole 10 is provided in a part of the lead 13.

The lead frame of this embodiment is first formed by punching out a thin metal plate as shown in FIG. 2. At this time, a portion (width W1: 0.3 mm) that supports a portion of the lead 13 that serves as a holding portion 13a. A hole (width W2: 0.2 mm) 10 is formed in the hole. Then, the semiconductor element 1 is die-bonded onto the sandwiching portion 13a, and the sandwiching portion 2a of the lead 2 is overlaid on the sandwiching portion 13a as shown in FIG. 1 to form bumps (not shown) on the semiconductor element 1.
Melt and perform wireless bonding. The hole 10
Is a through hole, but instead of forming this hole 10, the recess may be formed by thinning a part of the lead 13.

Since the portion where the hole 10 is formed has a smaller bending strength than the other portions of the lead 13, when stress is applied, the portion of the hole 10 first absorbs the stress due to deformation or bending. Therefore, even if the side frames 50 and 60 (FIG. 5) are clamped with a mold when the sandwiching portion 2a is positioned on the semiconductor element 1 and then the side frames 50 and 60 are heated at the time of soldering, the stress generated by the mold is not generated. Be absorbed. Therefore, the semiconductor element 1 is not stressed and is not destroyed. In addition, the bump does not come off. Although the hole 10 is provided in the lead 13 in the present embodiment, the hole may be provided in the lead 2 or both the leads 2 and 13.

When the bending strength of the lead 13 was measured,
It was found to be 50% lower than that without the holes 10. This is because stress concentration on the semiconductor element 1
This means that it is 50% lower than before. Further, by adjusting the size and shape of the holes, the magnitude of stress applied to the semiconductor element 1 can be adjusted.

If the entire lead frame is weakened, a problem will occur at the time of assembling the semiconductor device, but if the structure of the lead frame is partially provided with weak bending strength as in this embodiment, such a problem will occur. Does not occur. Further, if the portion having a small bending strength is sealed in the portion 4 (FIG. 7) to be molded with the resin, there will be no problem in handling the completed semiconductor device. Incidentally, if a part of the hole 10 is made to come out from the portion 4 (FIG. 7) to be molded with the resin, the adhesion between the molding resin and the lead is improved, so that the moisture resistance of the semiconductor device can be improved. .

The sandwiching portions 2a and 13a are shaped so as to be lifted up in order to position the semiconductor element 1 at the center of the package. It is also for preventing the leads 2 and 13 from coming off from the molding resin.

In the present embodiment, the width A1 of the holding portion 13a is larger than the width W1 of a part of the lead 13 which supports the portion to be the holding portion 13a, but the same size.
It may be (W1 = A1). The shape, size, etc. of the lead 13 are not limited to those in this embodiment as long as the sandwiching portion 13a constitutes the mounting portion of the semiconductor element 1.

Next, a second embodiment of the present invention will be described. The same parts as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted. FIG. 3 is a perspective view showing a state in which the semiconductor element 1 is mounted in the second embodiment of the present invention, and FIG. 4 is a plan view showing a main part structure before die bonding in the manufacturing process of the present embodiment. As shown in FIGS. 3 and 4, this embodiment is the same as the first embodiment (FIGS. 1 and 2) except that a constricted portion 20 is provided instead of the hole 10 (FIGS. 1 and 2). It has a structure of.

The lead frame of this embodiment is first formed by punching out a thin metal plate as shown in FIG. 4. At this time, a portion (width W1: 0.3 mm) that supports the portion of the lead 23 that serves as the holding portion 23a. However, the constricted portion (width W3: 0.1 mm) 20 is formed by making it thinner than the other portions. Even if the stress is generated, the constricted portion 20 absorbs the stress, so that the stress applied to the semiconductor element 1 is absorbed. In other words, this waist 20
Functions in the same manner as the portion provided with the hole 10 of the first embodiment. Although the constricted portion 20 is provided on the lead 23 in this embodiment, the constricted portion may be provided on the lead 2 or may be provided on both the leads 2 and 23.

Also in this embodiment, similarly to the first embodiment, the width A2 of the holding portion 23a is larger than the width W1 of a part of the lead 23 supporting the portion to be the holding portion 23a. They may have the same size (W1 = A2). The shape and size of the lead 23 are not limited to those in this embodiment as long as the sandwiching portion 23a constitutes the mounting portion of the semiconductor element 1.

Not only in the first and second embodiments described above, but in the structure of the portion which becomes the lead (for example, the portions which are not in direct contact with the semiconductor element 1 in the sandwiching portions 13a and 23a), the portions where the bending strength is weak. May be provided.

Further, in the lead frame which is usually used,
The width of the thinnest portion (in the first embodiment, the hole 10
Is equivalent to the sum of the widths of the supporting portions excluding
It is preferably in the range of 0.05 to 0.15 mm. The thinnest portion may be at least one place, and may be formed by providing a plurality of holes or a plurality of constricted portions, for example. Further, it is preferable to form the thinnest portion in a curved portion of the lead frame rather than in a flat portion. This is because stress is more likely to be concentrated in the curved portion, so that stress can be effectively relieved.

[0024]

As described above, according to the lead frame of the present invention, in the lead frame which has a plurality of leads extending from the side frame and which is used by sandwiching the semiconductor element with the two leads, of the two leads. Since at least one portion has a bending strength smaller than that of the other portion of the lead, even if a stress occurs, the portion having a small bending strength absorbs the stress and, as a result, is added to the die-bonded semiconductor element. Can absorb stress.

Therefore, it is possible to improve the yield and stabilize the performance of the semiconductor device. Further, since mechanical stress at the time of assembling the semiconductor device can be absorbed, there is an effect that facility design can be facilitated and a product having a wireless structure can be stably manufactured.

By molding a portion of the lead frame having the small bending strength with a resin together with the semiconductor element, it is possible to realize a semiconductor device having a strength that does not cause a problem in use.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a semiconductor element is mounted on a first embodiment of the present invention.

FIG. 2 is a plan view showing a main structure before die bonding in the manufacturing process of the first embodiment of the present invention.

FIG. 3 is a perspective view showing a state in which a semiconductor element is mounted on the second embodiment of the present invention.

FIG. 4 is a plan view showing a main part structure before die bonding in a manufacturing process of a second embodiment of the present invention.

FIG. 5 is a plan view showing a main part structure before die bonding in a manufacturing process of a conventional example.

FIG. 6 is a perspective view showing a state in which a semiconductor element is mounted on a conventional example.

FIG. 7 is a side view showing a state in which a semiconductor element is mounted on a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Semiconductor element 2 ... Lead 2a ... Clamping part 13,23 ... Lead 13a, 23a ... Clamping part 10 ... Hole 20 ... Constricted part

Claims (2)

[Claims] 1. A lead frame having a plurality of leads extending from a side frame, wherein a semiconductor element is sandwiched by two leads, wherein at least one part of the two leads has a part:
A lead frame having a bending strength smaller than that of other portions of the lead. 2. A semiconductor device, wherein the portion of the lead frame having the small bending strength according to claim 1 is molded with a resin together with the semiconductor element.