JPH10335361A - Metallic mold for resin sealing and semiconductor device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic mold for resin sealing in which a heat spreader set in a metallic mold can be held, and the positioned deviation of the heat spreader when it is incorporated in a package can be suppressed. SOLUTION: This metallic mold for resin sealing is constituted of a lower metallic mold 1A having a cavity and an upper metallic mold 1B, and a heat spreader 4A is placed in the cavity of the lower metallic mold 1A, an island 5 of a lead frame to which a semiconductor chip 6 is fixed is placed on the heat spreader 4A, an outside lead 7 of the lead frame is interposed between the lower metallic mold 1A and the upper metallic mold 1B, and a resin 10 is introduced. A groove 3A for fixing the lowermost face of the heat spreader 4A is provided on the bottom face part of the cavity of the lower metallic mold 1A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin sealing mold, a semiconductor device, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A method of manufacturing a semiconductor device having a heat spreader using a package made of a sealing resin will be described with reference to FIGS.

[0003] First, as shown in FIG.
A heat spreader 4 for improving the heat radiation of the package is placed in a lower mold 1A having a lead frame, and a lead frame island 5 on which a semiconductor chip 6 is fixed is placed thereon.
The outer lead 7 formed integrally with the inner lead 8 of the lead frame is sandwiched between the lower mold 1A and the upper mold 1B, and then the resin 10 is introduced into the cavity and sealed.

Next, as shown in FIG. 7, the package is removed from the mold, the external leads 7 are plated, cut into a desired shape, and formed. This semiconductor device is mounted on a mounting board 11, and the external leads 7 are connected to wirings 12 on the mounting board. In FIGS. 6 and 7, reference numeral 9 denotes a wire.

[0005]

The first problem is that the heat radiation of the package deteriorates.

The reason is that the position of the heat spreader 4 incorporated in the package is likely to be shifted in the package. Due to the displacement, the dissipation of the heat generated on the semiconductor chip 6 is deteriorated, or the dispersion of the displacement causes a large variation in heat radiation. Causes of this displacement include the positional accuracy when the heat spreader 4 is installed in the lower mold 1A before resin sealing, and the heat of the mold while the heat spreader 4 is installed in the mold. Deformation, displacement due to resin flow during resin sealing, and the like.

[0007] The second problem is that the internal wiring of the package is short-circuited.

[0008] The reason is that the resin flow during the resin sealing causes the heat spreader 4 to be displaced. Normally, in a resin-sealed semiconductor device with a heat spreader, the heat spreader 4
Is formed larger than the island 5, and when the resin flows and the position of the package is shifted upward, the heat spreader easily comes into contact with the internal lead 8.

A first object of the present invention is to hold a heat spreader installed in a mold in a resin sealing step,
An object of the present invention is to provide a resin sealing mold capable of suppressing a displacement of a heat spreader when incorporated in a package.

A second object of the present invention is to provide a semiconductor device having a uniform and stable heat dissipation property by eliminating the displacement of a heat spreader built in a package, and a method of manufacturing the same.

[0011]

According to a first aspect of the present invention, there is provided a resin mold for a resin-sealing mold comprising a lower mold having a cavity and an upper mold, wherein a heat spreader is provided in a cavity of the lower mold, and a semiconductor is provided. An island of a lead frame to which a chip is fixed is placed on the heat spreader, and an external lead of the lead frame is sandwiched between the lower mold and the upper mold. A groove for fixing a lowermost portion of the heat spreader is provided on a bottom surface of the cavity.

According to a second aspect of the present invention, there is provided a semiconductor device, comprising: a semiconductor chip fixed on a heat spreader via an island; an internal lead provided at a peripheral portion of the island and integrally formed with an external lead; In a semiconductor device having a wire connecting a lead and the semiconductor chip, and a resin sealing the heat spreader, the semiconductor chip, the internal lead, and the wire, a lowermost portion of the heat spreader is exposed And protruding from the sealing resin surface.

According to a third aspect of the invention, there is provided a method of manufacturing a semiconductor device, comprising: fixing a support portion of a heat spreader in a groove provided in a cavity of a lower mold; It is mounted on a spreader, and the external leads of the lead frame are sandwiched between the lower mold and the upper mold, and a resin is introduced and sealed.

In the resin sealing step, when the heat spreader is installed in the lower mold, a groove is formed in the installation portion of the heat spreader in the lower mold so as to conform to the shape of the lowermost surface of the heat spreader. By installing the heat spreader along the groove, the heat spreader is fixed by the groove, and the heat spreader does not shift during the resin sealing step.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a resin-sealing mold when a lead frame to which a semiconductor chip is fixed is set for explaining the first embodiment of the present invention.

The resin sealing mold of the first embodiment comprises a lower mold 1A having a cavity 2A and an upper mold 1B having a cavity 2B. A groove 3A for fixing a supporting portion (lowest surface) 14 of a heat spreader 4A made of a copper-based metal in consideration of thermal characteristics is provided in a bottom portion of the cavity 2A.
Next, a case where a semiconductor chip is sealed with a resin using this mold will be described.

First, the support portion 14 of the heat spreader 4A is inserted into a groove 3A provided in the cavity 2A of the lower mold 1A.
Then, the lead frame island 5 to which the semiconductor chip 6 is fixed is placed on the heat spreader 4A, and the external lead 7 integrally formed with the internal lead 8 of the lead frame is connected to the lower mold 1A and the upper metal mold. With the mold 1B, the resin 10 is introduced and sealed. The heat spreader 4A for mounting the semiconductor chip 6 and improving the heat radiation effect of a package made of resin and a lead frame for making an electrical connection to the outside uses a copper-based metal in consideration of thermal characteristics.
The lead frame and the heat spreader 4A are formed in a predetermined shape by etching or pressing. Regarding the heat spreader 4A, first, it is better to make the size as large as possible in consideration of thermal characteristics. However, if the size is too large, there is a concern that the heat spreader 4A may be separated from the sealing resin due to a difference in expansion coefficient. For a 28mm package, the size of the heat spreader 4A is □ 2
About 0 to 24 mm is desirable.

The support portion 14 of the heat spreader is
It has a shape that supports the heat spreader 4A, is held when installed in the lower mold during the resin sealing step, and is flush with the external lead formed by protruding outside the package. Is L-shaped (gull wing) processed. On the other hand, a heat spreader 4 is provided on the bottom surface of the lower mold 1A used in the resin sealing step.
In order to hold the support portion 14 of A, a predetermined groove adapted to the support portion, for example, four grooves 3A as shown in FIG. 5 (a) or a circular groove as shown in FIG. 5 (b) (or Oval) 3B is applied by machining or the like.

Next, a method of manufacturing a semiconductor device using this mold will be described as a second embodiment.

First, the semiconductor chip 6 is mounted on the island 5 of the lead frame via an adhesive, and the electrode pads on the predetermined semiconductor chip 6 and the plated front ends of the internal leads 8 of the lead frame are Au. And so on. In the next resin sealing step, first, as shown in FIG.
The heat spreader 4A is set on the bottom surface of the lower mold 1A in which the groove 3A is formed in conformity with the shape of the groove 3A, and then the semiconductor chip 6 is mounted and the lead frame is connected to the internal lead. The outer leads 7 are sandwiched between upper and lower dies, and then resin 10 is supplied to perform sealing molding.
Thereafter, the external leads 7 of the package are plated and cut into a desired shape. At this time, the groove 3A of the lower mold 1A
Heat spreader support 14 buried inside
Has a structure protruding outside the package. Thus, the resin-sealed semiconductor device of the present invention is obtained.

The semiconductor device manufactured in this manner is
As shown in FIG. 2, it is mounted on the mounting board 11. At this time, the external leads 7 are connected to the wirings 12 on the mounting board 11. Furthermore, since the support portion 14 exposed from the package can be connected to the heat radiation pattern 13A on the mounting substrate 11, heat radiation is improved.

When a semiconductor device is manufactured using the mold of the present invention, as shown in FIG. 1, when the heat spreader 4A is installed in the lower mold 1A in the resin sealing step, Since the support portion 14 of the heat spreader 4A is installed and held so as to fit into a predetermined groove 3A provided in the lower mold, first, the heat spreader 4A
Eliminates positional deviation and variation when supplying A.
In addition, since the heat spreader 4A does not slide or is lifted upward due to the flow of the resin during the resin sealing, when the resin 10 is cured, the position of the heat spreader 4A with respect to the package is eliminated, and the original design is achieved. It can be arranged at a regular position. As a result, it is possible to secure stable heat radiation for the heat of the semiconductor chip in the package. In addition, problems such as contact with internal leads caused by displacement of the heat spreader do not occur. Further, the support portion 14 of the heat spreader 4A protrudes outside the package, and the protruding portion is directly bonded to the mounting board 11, so that the □ 28mm package has a size smaller than that of the conventional package. It has become possible to reduce the thermal resistance by about 10%.

FIG. 3 is a sectional view of a semiconductor device according to a third embodiment of the present invention. In the third embodiment, a heat spreader having a shape such that the plane of the heat spreader 4B is exposed on the surface of the package 10 is used. That is, the heat spreader 4B having the thickness of the lower half resin thickness of the semiconductor device is used. Also in this case, as shown in FIG.
As in the embodiment shown in FIG. 1, a groove 3C (carved) having a shape corresponding to the shape exposed on the surface of the package is formed in a portion of the surface of the lower mold 1A where the heat spreader 4B is installed.

Using these, in the case of a semiconductor device obtained by a manufacturing method similar to that of the second embodiment, in addition to the structure of bonding the exposed heat spreader 4B to the mounting substrate 11 similarly to the second embodiment. For example, the fourth type shown in FIG.
As in the above embodiment, the package is formed in a cavity-down structure, the heat spreader 4B is exposed and protruded from the package surface (upper surface), and the heat sink 15 is attached to the exposed surface, thereby further reducing the thermal resistance. . When the heat spreader 4B is exposed and protruded on such a package surface, the heat resistance is reduced by about 15 to 20% as compared with the conventional built-in structure.

In addition, when a circular heat spreader is used, if the circular groove 3B as shown in FIG. 5B is formed, the heat spreader is always set at a fixed position. It is possible to do.

[0026]

The first effect is that a stable heat dissipation can be obtained in the semiconductor device, and problems such as short-circuiting of wiring caused by displacement of the heat spreader can be suppressed.

The reason is that the heat spreader is always held in a stable position in the package because the heat spreader is held by the groove provided in the lower mold.

The second effect is that heat dissipation is improved.

The reason is that the heat spreader is exposed to the outside of the package of the semiconductor device and is connected to a heat radiating member such as a mounting board and a heat sink, so that the heat generated in the package is easily released.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mold for explaining a first embodiment of the present invention.

FIG. 2 is a sectional view of a semiconductor device for explaining a second embodiment of the present invention;

FIG. 3 is a cross-sectional view of a semiconductor device for describing a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of a semiconductor device for describing a fourth embodiment of the present invention.

FIG. 5 is an upper drawing showing a shape of a groove formed in a lower mold of the present invention.

FIG. 6 is a sectional view for explaining a conventional mold.

FIG. 7 is a cross-sectional view of an example of a conventional semiconductor device.

[Explanation of symbols]

 1A Lower mold 1A Upper mold 2A, 2B Cavity 3A-3C Groove 4, 4A, 4B Heat spreader 5 Island 6 Semiconductor chip 7 External lead 8 Internal lead 9 Wire 10 Resin 11 Mounting board 12 Wiring 13A, 13B Heat radiation pattern 14 Support part 15 heat sink

[Procedure amendment]

[Submission date] August 28, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

[0011]

Means for Solving the Problems The first invention for resin sealing
The mold is composed of a lower mold having a cavity and an upper mold, a heat spreader is placed in the cavity of the lower mold, and an island of the lead frame to which the semiconductor chip is fixed is placed on the heat spreader, and the lead frame In the resin-sealing mold that introduces resin by sandwiching the external leads between the lower mold and the upper mold, a groove for fixing the support portion of the heat spreader is formed on the bottom surface of the cavity of the lower mold. It is characterized by having been provided.

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Claims (8)

[Claims] 1. A lower mold having a cavity and an upper mold, a heat spreader is placed in a cavity of the lower mold, and an island of a lead frame to which a semiconductor chip is fixed is placed on the heat spreader. An outer lead of a frame sandwiched between the lower mold and the upper mold, and a resin sealing mold for introducing a resin, for fixing a lowermost surface of the heat spreader to a bottom surface of a cavity of the lower mold. A resin sealing mold having a groove. 2. The resin sealing mold according to claim 1, wherein a plurality of grooves are provided. 3. The resin sealing mold according to claim 1, wherein the groove is provided in a rectangular shape. 4. The resin sealing mold according to claim 1, wherein the groove is provided in a circular or elliptical shape. 5. A semiconductor chip fixed on a heat spreader via an island, an internal lead provided at a peripheral portion of the island and integrally formed with an external lead, and the internal lead and the semiconductor chip. In a semiconductor device having a wire to be connected, and a resin for sealing the heat spreader, the semiconductor chip, the internal lead, and the wire, a lowermost portion of the heat spreader is exposed and protrudes from a sealing resin surface. A semiconductor device characterized in that: 6. The semiconductor device according to claim 5, wherein the lowermost portion is formed in a rectangular shape. 7. The semiconductor device according to claim 5, wherein a heat sink is connected to an exposed surface of the heat spreader. 8. A heat spreader supporting portion is fixed in a groove provided in a cavity of a lower mold, an island of a lead frame to which a semiconductor chip is fixed is placed on the heat spreader, and an external lead of the lead frame is provided. A resin is introduced between the lower mold and the upper mold, and sealing is performed.