JPH0750761B2 - Plane mounting form of resin-encapsulated semiconductor device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar mounting form of a resin-encapsulated semiconductor device, and more particularly to a planar mounting form effective for improving heat dissipation when applied to a resin-encapsulated semiconductor device of a thin package. Pertain.

[0002]

2. Description of the Related Art Resin packages are widely used because they are less expensive than ceramic packages, and in particular, those having a package shape as shown in FIG. 2 (A) or (B). In recent years, the demand for miniaturization of equipment has shown a great increase in demand.

In the figures (A) and (B), 1 is a resin model.
The envelopes 2 ... and 2 '... which are made of the cathode layer are lead pins. In the case of FIG. 2 (A), after the lead pins 2 extending from the side wall of the resin envelope 1 are bent to the bottom level of the envelope, the tip portion of the lead pin 2 is further attached to the bottom face of the envelope. In the case of FIG. 1B, the lead pins 2 '... which are extended from the side wall of the envelope 1 and are bent to the bottom level of the envelope are terminated as they are. Has been done. Both differ only in this respect, and all other structures are the same. In either case, a semiconductor chip (not shown) is sealed inside the envelope 1, and the lead pins 2 ..., 2 '...
Are bonded to the internal terminals of this semiconductor chip.

In the resin-encapsulated semiconductor device shown in FIGS. 2A and 2B, the thickness of the resin envelope 1 is extremely thin as compared with a normal DIP type package, and therefore the flat package is generally used. -Although it is called a "type", there is no clear definition of a flat package. Therefore, in this specification, a resin-encapsulated package in which the thickness of the resin envelope is not more than 15 times the thickness of the lead pin and which is lead-formed so as to be planarly mounted is a flat package. I'll call it Ji.

[0005]

[Problems to be Solved by the Invention] The above flat package
J has the advantage that the resin-encapsulated semiconductor device can be miniaturized as described above, but has the following problems in terms of heat dissipation.

That is, the resin envelope originally has low heat dissipation, and the heat dissipation effect of the resin-sealed package basically depends on the size of the envelope. For this reason, a relatively large envelope such as a DIP package is contrary to the demand for miniaturization because the envelope becomes very large, but it still consumes a certain amount. It is possible to obtain a heat dissipation effect that can cover up to electric power (for example, about 100 pins).
However, in the flat package thin envelope, since the absolute amount of heat radiation by the resin mold layer is small, there is a problem that the range of application must be limited to those with low power consumption.

On the other hand, a user for a resin-encapsulated semiconductor device
As a need on the user side, there is an increasing demand for lighter, smaller, and more multifunctional devices, and even those with considerable power consumption are required to be mounted in the flat package type.
In order to meet this demand, the inventor has proposed a flat package provided with heat radiation fins, but even in this case, the range of application cannot be expanded until the demand can be sufficiently met. Especially, the problem remains in the case of single product mounting.

The present invention has been made in view of the above circumstances. For the purpose of expanding the application range of a resin-sealed semiconductor device by a flat package, a heat radiation effect is obtained by a combination of a radiation fin and a printed wiring board structure to be mounted. Is intended to be further improved.

[0009]

SUMMARY OF THE INVENTION The present invention is a planar mounting type thin package (flat package) provided with a radiation fin.
When mounting the resin-encapsulated semiconductor device according to J.) on the printed wiring board, a heat radiation pattern is provided on the printed wiring board in addition to the wiring pattern, and the resin-encapsulated semiconductor device is printed on the printed wiring board. The heat radiation effect is improved by joining the heat radiation fins to the heat radiation pattern formed on the printed wiring board when the board is mounted on the board in a plane.

That is, in the planar mounting form of the resin-sealed semiconductor device according to the present invention, the semiconductor chip mounted on the heat radiation fin via the solder layer and the bonding wire to the internal terminal formed on the surface of the semiconductor chip. A resin mold layer that seals the semiconductor chip, the semiconductor chip mount portion of the heat radiation fin, and the wire bonding portion of the lead. A resin-sealed semiconductor device in which the thickness of the solder layer is 15 times or less the thickness of the lead pin and is configured to be mounted on a plane, and a wiring pattern and a heat radiation pattern are formed. And the lead pattern of the resin-encapsulated semiconductor device is connected to the wiring pattern.
And the heat radiation fins are bonded to the heat radiation pattern for planar mounting.

[0011]

According to the present invention described above, in addition to the heat radiation effect of the heat radiation fins, the heat radiation effect of the heat radiation pattern on the printed wiring board can be obtained, and as a result, it can be applied to those having considerable power consumption. It is possible to meet the demand for expanding the application range of flat packages.

[0012]

EXAMPLE First, a resin packaged semiconductor device of a flat package to which the mounting form of the present invention is applied will be described. FIGS. 3A to 3C are perspective views showing the example.
2 (A) and 2 (B) correspond to FIGS. 2 (A) and 2 (B), respectively, in which 11 is an envelope made of a resin mold layer and 12, 12 '... -Dopin, 13,
13 'is a radiation fin. These resin-sealed semiconductor devices shown in FIGS. 3A and 3B have exactly the same structure except that the lead pins and the radiation fins have different forming shapes.

On the other hand, in the resin-sealed semiconductor device of FIG. 3C, the lead pins 22 ... And the radiation fins 23, 23 are provided.
Is different from the structure of FIGS. 9A and 9B in that it is extended only in two directions from the side wall of the resin mold layer 21.
However, the envelope 21 is thin, and the lead pins 22 ... And the radiation fins 23, 23 are formed into a shape for planar mounting.
The structure is common to the structure shown in FIG. 4A in that it is marked, and this is also classified as a flat package type.

Next, the internal structure and manufacturing method of the resin-sealed type semiconductor device by such a flat package with heat radiation fins will be described with reference to FIG. 3C as an example. This is performed using the lead frame 30 shown. The lead frame 30 is formed by punching a thin metal plate to obtain leads 22, ... And heat radiation fins 23.
A predetermined pattern such as the above is formed. Figure 3 (C)
In manufacturing the resin-encapsulated semiconductor device, the semiconductor chip 24 is first die-bonded on the bed portion provided in the central portion of the heat dissipation fins 23, 23 with a mount agent such as a silver / epoxy adhesive. , Wire bonding is performed as shown. Then, a resin mold layer 21 for sealing the region shown by the one-dot chain line in the figure is formed by a transfer mold of epoxy resin or the like, and then each pattern is read frame along the broken line in the figure. Separate from the outer frame. Further, the separated leads 22 ... And the radiation fins 23, 2
By bending 3 and forming it into a predetermined shape, the planar mounting type resin-sealed semiconductor device shown in FIG. 3C is obtained.

One of the advantages of the resin-encapsulated semiconductor device thus obtained is as follows. That is, the metal pattern (the resin mold layer 21) is also formed on the longitudinal end face of the resin mold layer 21 (the end face where the leads 22 do not extend).
Functioning as a hanging pin) of the semiconductor chip 24 is exposed, but this pattern is not connected to the bed portion on which the semiconductor chip 24 is mounted. Therefore, the water penetrating along this metal pattern does not reach the semiconductor chip 24,
The problem of reliability deterioration due to corrosion can be suppressed.

In FIG. 4, among the through holes formed in the radiation fin 23, the through holes 23a near the resin sealing boundary are provided.
Is for strengthening the holding force of the fin by the resin mold layer. That is, in the planar mounting type, since the resin mold layer is thin, it provides the strength required when the fin is bent. Further, the through hole 23b provided near the bed portion prevents the flow of the mount agent when the semiconductor chip 24 is die-bonded, and does not hinder the wire bonding to the radiation fin. Further, the heat radiating fins 23, 23 are formed by constricting the sealed portions on both sides of the bed, and the width thereof is narrowed for the following reason. The first reason is that when the fins are soldered to the radiator of the printed wiring board, the heat is
This is to suppress the transmission to No. 4. The second reason is to prevent mechanical stress when bending and forming the fins from spreading to the inside of the resin mold layer,
This is to prevent a decrease in moisture resistance due to the generation of gaps.

3A or 3B in which the radiation fins and the lead pins are provided in four directions, the lead frame formed by such a pattern is used. It can be manufactured in the same manner as above.

Next, the mounting form according to the present invention is applied to the resin-sealed semiconductor device of FIG. 3A having the above structure,
An embodiment in which the heat radiation effect of the radiation fins 13 ... Is improved will be described.

FIG. 1 is a perspective view showing this embodiment, and FIG.
The resin-encapsulated semiconductor device by the flat package of (A) is planarly mounted on the printed wiring board 40.
The printed wiring board 40 is composed of a portion 41 for mounting the resin-sealed semiconductor device on a plane and a plug portion 42 for incorporating the resin-sealed semiconductor device in a separate circuit board. The mounting portion has a copper foil pattern for wiring on the surface thereof. 43, as well as copper foil patterns 44 for heat dissipation are formed. Further, this printed wiring board 40 has a laminated structure using a glass epoxy plate, and has a copper foil pattern 43 for wiring formed on the mounting portion.
Are connected to a copper foil pattern 45 formed on the surface of the plug portion 42 through an internal wiring layer. And FIG.
The resin-encapsulated semiconductor device of FIG.
Is soldered on the terminals of the wiring pattern 34 formed on the surface of the printed circuit board mounting portion 41, and the heat radiation fin 13 is provided.
Is a heat radiation pattern 4 formed on the surface of the board mounting portion 41.
4 is mounted on the surface by soldering on the surface of the surface 4.

In the mounting form of the above-mentioned embodiment, the heat radiation fins 23 of the resin-sealed semiconductor device mounted on the plane are formed on the surface of the mounting portion of the printed wiring board, and the copper foil pattern for heat radiation has no wiring function. The substantial heat dissipation area of the heat dissipation fin is increased by soldering to the heater 44. As a result, compared to the case of using only the heat radiation fins 13, a large amount of heat radiation can be reliably obtained by the amount of heat radiation by the copper foil pattern 44 for heat radiation, which is not possible with conventional semiconductor chips with large power consumption. However, the flat package can be applied. In fact, when the width of the heat dissipation copper foil patterns 44 ... In the mounting form of the above-mentioned embodiment was changed and the power consumption in the semiconductor chip possible with the same package was examined, a clear dependence between the two was found. Was confirmed, and the effectiveness of the heat radiation copper foil pattern 44 was confirmed.

FIG. 5 is a perspective view showing another embodiment in which the mounting form according to the present invention is applied to the resin-sealed semiconductor device of FIG. 3 (A). In this embodiment, the entire back surface of the printed wiring board mounting portion 41 is covered with a copper foil 46, and the heat radiation copper foil pattern 43 ... Formed on the front surface is extended along the side wall of the mounting portion 41. It is connected to the copper foil 46 on the back surface. The other structure is exactly the same as that of the embodiment shown in FIG. In this embodiment, in addition to the heat-dissipating copper foil pattern 43 formed on the front surface of the printed board mounting portion 41, the heat dissipation effect is added by the large-area copper foil 46 formed on the entire back surface of the printed circuit board mounting portion. Even when compared with the embodiment of FIG. 1, heat dissipation can be obtained several times, and the flat package can be applied to a semiconductor chip which consumes a large amount of power.

By the way, it is also possible to selectively expose the iron plate used as the core material on the inner layer of the wiring board 40 and solder the radiation fin 23 to the exposed portion to increase the effect of the radiation fin. However, in this case, since the exposed area of the iron plate is extremely small, the effect is inevitably inferior as compared with the case of the above embodiment.

Although the above-mentioned embodiments are all applied to the mounting of the resin-encapsulated semiconductor device of FIG. 3A, the present invention is applied to the resin of FIGS. 3B and 3C. The same can be applied to the sealed semiconductor device.

Further, although the lead pins are in four directions as in FIG. 3A, the radiation fins are provided in three directions, two directions, or only one direction with respect to the resin-sealed semiconductor device. Can be similarly applied.

Further, the heat radiation copper foil patterns 43 ... May be formed in an arbitrary plane pattern shape.

[0026]

As described in detail above, according to the present invention, the heat dissipation effect by the heat dissipation fin can be increased without significantly changing the specifications of the printed wiring board used for mounting the flat package from the conventional one. As a result, a remarkable effect can be obtained such that the range of application of the thin resin-sealed semiconductor device by the flat package can be remarkably expanded.

[Brief description of drawings]

FIG. 1 is a perspective view showing a mounting form of a resin-sealed semiconductor device according to an embodiment of the present invention.

2A and 2B are perspective views showing a resin-sealed semiconductor device using a conventional flat package.

3A to 3C are perspective views showing the appearance of a resin-encapsulated semiconductor device using a flat package with heat dissipation fins to which the mounting form of the present invention is applied.

FIG. 4 is a plan view for explaining a manufacturing process and an internal structure of the resin-sealed semiconductor device of FIG. 3 (C).

FIG. 5 is a perspective view showing a mounting mode according to another embodiment of the present invention.

[Explanation of symbols]

11, 21 ... Resin mold layers, 12, 12 ', 22 ... Lead pins, 13, 13', 23 ... Radiating fins, 23a,
23b ... Through hole, 24 ... Semiconductor chip, 25 ... Bonding wire, 30 ... Lead frame, 40 ... Printed wiring board, 41 ... Mounting part, 42 ... Plug part,
43, 45 ... Copper foil pattern for wiring, 44 ... Copper foil pattern for heat dissipation, 46 ... Copper foil.

Claims (2)

[Claims] 1. A semiconductor chip mounted on a heat dissipation fin via a solder layer, a lead pin connected to an internal terminal formed on the surface of the semiconductor chip via a bonding wire, and the semiconductor chip, The resin mold layer for sealing the semiconductor chip mount portion of the heat radiation fin and the wire bonding portion of the lead is provided, and the thickness of the resin mold layer is 15 times the thickness of the lead pin. A resin-encapsulated semiconductor device that is less than double the number and is configured to be mounted in a plane, and a resin printed wiring board on which a wiring pattern and a heat radiation pattern made of a conductive metal are formed. A plug portion for incorporating the wiring board into another circuit board is provided at one end thereof, and a terminal pattern made of a conductive metal film connected to the wiring pattern is provided on the surface of the plug portion. A printed wiring board on which a lead is formed, each lead pin of the resin-encapsulated semiconductor device is bonded to the wiring pattern, and the heat radiation fin is connected to the heat radiation pattern. A planar mounting form of a resin-encapsulated semiconductor device, which is joined and planarly mounted. 2. A semiconductor chip mounted on a radiation fin via a solder layer, a lead pin connected to an internal terminal formed on the surface of the semiconductor chip via a bonding wire, the semiconductor chip, The resin mold layer for sealing the semiconductor chip mount portion of the heat radiation fin and the wire bonding portion of the lead is provided, and the thickness of the resin mold layer is 15 times the thickness of the lead pin. A printed wiring board having a resin-sealed semiconductor device configured to be mounted in two or less times and planarly mounted, and a wiring pattern and a heat radiation pattern made of a conductive metal. A heat dissipation pattern is formed on a printed wiring board that is continuously formed on the front surface and the back surface of the wiring board, and each lead pin of the resin-encapsulated semiconductor device is connected to the wiring pattern. And, and the radiation fins the heat radiating pattern - plane implementation of a resin sealed semiconductor device which is characterized in that the surface mounting bonded to down.