JPH0714868A - Resin-sealed semiconductor device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to prevent variations in heat dissipation characteristics of the resin-encapsulated semiconductor device and to make the quality uniform. [Structure] In the resin-encapsulated semiconductor device, it is opposite to the lead side Since a part of the short-side portion of the metal support plate on the side is fixed with a mold and resin-sealed, the pressure of the resin at the time of resin-sealing prevents the metal support plate from being curved, It is possible to make the resin thickness on the back surface side uniform and improve the accuracy of heat dissipation characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-encapsulated semiconductor device, and is preferably applied mainly to a resin-encapsulated transistor.

[0002]

2. Description of the Related Art FIG. 11 is a perspective view of a conventional resin-sealed power transistor, and FIG. 12 is a perspective view thereof before being molded.

In these figures, the lead frame 10
The pellet 2 is attached to the metal supporting plate 1 by soldering or the like, and is connected to the external lead 4 of the lead frame 10 by the wire 3.

In order to construct a transistor assembly machine using such a lead frame 10 and to make it into a sealing structure shown in FIG. 11, as shown in FIG. The metal supporting plate 1 is placed in a space formed between the lower molds 7 in a floating manner, and then resin is injected into the space. By this injection, the resin is also filled in the space just below the back surface of the metal supporting plate 1, and the sealing structure shown in FIG. 11 is formed.

[0005]

When resin encapsulation is performed in the step shown in FIG. 13, resin injection is performed with only the outer lead forming side of the lead frame 10 being sandwiched by the upper and lower molds. Therefore, the metal supporting plate 1 may be bent in the space due to the pressure of the resin. Such bending of the metal support plate 1 causes variations in the thickness of the thin resin layer on the back surface side of the metal support plate 1, and due to this variation,
The heat dissipation characteristics of the transistor vary.

An object of the present invention is to provide a resin-encapsulated semiconductor device that solves the above-mentioned problems, prevents the occurrence of variations in heat dissipation characteristics, and makes the quality uniform.

[0007]

According to the present invention, a semiconductor pellet is fixed to one main surface of a metal supporting plate, the pellet and a lead are electrically connected, and the semiconductor pellet and a part of the lead are surrounded. Then, a part of the end surface portion of the metal supporting plate on the side opposite to the lead-out side is fixed with a mold and sealed with a resin, which is a resin-sealed semiconductor device.

Further, according to the present invention, a semiconductor pellet is fixed to one main surface of a metal supporting plate, the pellet and the lead are electrically connected, and the semiconductor pellet and a part of the lead are surrounded, and the lead is led out. A resin-sealed semiconductor device in which a part of an end face portion of the metal support plate on the side opposite to the metal mold is fixed with a mold and sealed with a resin, and the recess of the resin-sealed body is generated by fixing the mold. In the resin-encapsulated semiconductor device, the opening end width of is smaller than at least one of the width of the protrusion and the width of the lead sandwiched between the recess and the side surface of the resin encapsulant. is there.

[0009]

According to the present invention, since a part of the end surface portion of the metal supporting plate on the side opposite to the lead lead-out side is fixed by the mold, the bending of the metal supporting plate is caused by the pressure of the resin during the resin sealing. Can be prevented.

Further, according to the present invention, the width of the concave portion of the resin-sealed body caused by fixing the mold is either the width of the convex portion sandwiched between the concave portion and the side surface of the metal supporting plate or the width of the lead. By making it smaller than one of them, even when a plurality of semiconductor devices are simultaneously conveyed, it is possible that one of the first convex portion or the lead of one semiconductor device fits into the first concave portion of another semiconductor device. Therefore, one semiconductor device can prevent the other semiconductor devices from being destroyed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view after resin sealing of a resin-sealed power transistor showing an embodiment of the present invention, FIG. 2 is its front view, FIG. 3 is its plan view, and FIG. The side view is shown.

The external appearance of the transistor is a resin package 1.
1 and a lead 12, and a resin package 11
Is a main body 13 in which a semiconductor chip is sealed and a mounting hole 1
4 is formed of a mounting portion 15.

As shown in FIG. 5, the transistor is fixed to an aluminum plate 17 which functions as a heat radiation plate by inserting a screw 16 into the mounting hole 14, and is arranged on a printed circuit board 18 in this state. It

FIG. 6 is a perspective view of a transistor before resin sealing, and FIG. 7 is a side sectional view showing a state in which a transistor is placed in a mold for resin sealing.

The semiconductor chip 22 is mounted on the metal supporting plate 21 of the lead frame 20 by soldering or the like, and the external lead 12 of the lead frame 20 is connected by the wire 23.
And is fixed to the upper and lower molds 25 and 26 in this state (see FIG. 7). In this manner, the lead frame 20 is fixed by the upper and lower molds 25 and 26, and is resin-sealed by injecting a resin such as epoxy to form the resin package 11.

In this type of transistor, in order to improve the heat dissipation, the resin thickness d on the back surface 31 side of the metal supporting plate is set.
It is desirable that 4 is as small as possible, which is achieved by reducing the gap 30 between the metal support plate 21 and the lower mold 26.

However, if the gap 30 is made as small as possible, the metal supporting plate 21 is likely to come into contact with the lower mold, and there is a risk that the resin will not enter the gap 30 between the metal supporting plate 21 and the lower mold 26.

Therefore, when the resin is injected, the upper and lower molds 25,
By holding the lead 12a integrated with the metal supporting plate 21 by 26, and by holding a part of the tip portion 21a of the metal supporting plate 21 on the side opposite to the lead 12a, the metal supporting plate 21 is held. The upper and lower molds 25,
It is possible to securely fix it by means of 26, and to keep the size of the gap 30 constant so that the resin can be surely introduced into the gap 30. Also, in this way, the metal supporting plate 2
By fixing the tip portion 21a of No. 1, it is possible to prevent occurrence of variation in the thickness of the thin resin layer on the back surface side of the metal supporting plate 1 without being bent in the void due to the pressure of the injected resin. As a result, the accuracy of the heat dissipation characteristics of the transistor can be improved.

When the front end portion 21a of the metal supporting plate 21 is clamped, the protruding portions 25a provided on the upper and lower molds 25, 26,
A portion of the tip portion 21a is clamped by 26a. The reason why the entire surface of the tip portion 21a is not sandwiched is to minimize the exposed portion of the metal support plate 21 formed at a position corresponding to the mold in the resin package 11 after the resin is sealed.

After the resin is filled, the resin package 1
1, concave portions 33a and 33b are formed at positions corresponding to the protruding portions 25a of the upper die 25 of the tip portion 21a, and concave portions 33c and 33 are formed at positions corresponding to the protruding portion 26a of the lower die 26.
d (hereinafter collectively referred to as a recess 33) is formed.

The width W1 of each concave portion 33 is equal to that of the convex portion 34a, 34b, 34c, 34d (hereinafter referred to as convex portion 34 when collectively referred to) sandwiched between each concave portion 33 and both side portions 11a, 11b of the resin package 11. It is selected to be smaller than the width W2 and smaller than the width W3 of the lead 12. In this embodiment, the width W2 of each convex portion 34 is 1.05 mm and the width W3 of the leads 4a and 4b is 0.80 mm, while the width W1 of the opening end of each concave portion 33 is 0.75 mm. There is.

The reason for having such a structure is as follows. That is, temporarily, the width W1 of the opening end of each recess 33 is
Are formed so as to be larger than the width W2 of each of the convex portions 34 and larger than the width W3 of the lead 12, the concave portions 33 of the transistor are formed in the concave portions 33 of the other transistor.
4 or the lead 12 may be inserted or fitted. For example, in the case of adopting the bulk method in which a plurality of transistors are separately packed in one bag at the time of factory shipment, the bulk method is adopted. The parts are often inserted or fitted, and in this state, if an undesired force is applied from the outside, the convex parts 34 may be broken as shown in FIG. When a part of the transistor is destroyed in this way, a crack is generated from the destroyed part and the quality of the transistor is deteriorated.

Therefore, by adopting the above-mentioned structure, even if the above-mentioned bulk method is adopted, the respective convex portions 34 of the other transistor or the leads 12 can be inserted or fitted into the respective concave portions 33 of one transistor. Cannot happen,
Therefore, as shown in FIG. 8, each convex portion 34 is not destroyed. Therefore, even if a simple packaging form is adopted, it is possible to prevent deterioration of the quality of the product during transportation.

In this embodiment, the shape of each recess 33 is rectangular, but the shape is not limited to this, and the opening may have a trapezoidal shape as shown in FIG. 9 or an arc shape as shown in FIG. Similar effects can be obtained if the width W1 of the edge satisfies the above-mentioned conditions.

In each of the above embodiments, the width W1 of the opening end of each recess 33 is selected to be smaller than the width W2 of each protrusion 34 and smaller than the width W3 of the lead 12, but the width of each recess 33 is not limited to this. W1 is the width W2 of each protrusion 34 and the lead 12
The width W3 may be smaller than only one of the widths W3. As a result, it is possible to prevent at least one of the convex portion 34 and the lead 12 from being inserted or fitted into the concave portion 33, so that it is possible to prevent the deterioration of the quality.

[0026]

As described above, according to the present invention, since a part of the end face portion of the metal supporting plate on the side opposite to the lead-out side is fixed with a mold, the pressure of the resin at the time of sealing the resin causes The curvature of the metal support plate can be prevented, the thickness of the resin on the back side of the resin metal support plate can be made uniform, and the accuracy of the heat dissipation characteristics of the semiconductor device can be improved.

Further, according to the present invention, even if a simple packaging form in which a plurality of semiconductor devices are collectively packaged separately at the same time is adopted, the other semiconductors are formed in the concave portion of the resin sealing body of one semiconductor device. The problem that one semiconductor device or another semiconductor device is destroyed without the projections or leads of the device being inserted or fitted and the quality deterioration can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of a transistor according to an embodiment of the present invention after resin sealing.

[Figure 2] Front view

FIG. 3 is a plan view thereof

[Figure 4] Side view

FIG. 5 is a diagram showing a state in which a transistor is installed on a printed circuit board.

FIG. 6 is a perspective view of a transistor before resin sealing.

FIG. 7 is a sectional view showing a state in which a transistor is arranged in a mold.

FIG. 8 is a reference diagram for explaining an effect of one embodiment of the present invention.

FIG. 9 is a diagram showing a second embodiment of the present invention.

FIG. 10 is a diagram showing a third embodiment of the present invention.

FIG. 11 is a perspective view of a conventional transistor.

FIG. 12 is a perspective view of a conventional transistor before resin sealing.

FIG. 13 is a sectional view showing a state in which a conventional transistor is arranged in a mold.

[Explanation of symbols]

 11 · · · Resin package 12 · · · Lead 21 · · · Metal support plate 21a · · · Tip 33 · · · Recessed portion 34 · · · Convex

Claims (2)

[Claims] 1. A semiconductor pellet is fixed to one main surface of a metal supporting plate, the pellet and a lead are electrically connected to each other, and the semiconductor pellet and a part of the lead are surrounded and are opposite to the lead lead-out side. A resin-encapsulated semiconductor device, characterized in that a part of an end face portion of the metal support plate on the side is fixed with a mold and sealed with a resin. 2. A semiconductor pellet is fixed on one main surface of a metal supporting plate, the pellet and a lead are electrically connected to each other, and the semiconductor pellet and a part of the lead are surrounded, and a side opposite to the lead lead-out side. A resin-sealed semiconductor device in which a part of an end face portion of the metal support plate is fixed with a mold and sealed with a resin, the opening end width of a recess of a resin-sealed body caused by fixing the mold. Is smaller than at least one of the width of the projection and the width of the lead sandwiched between the recess and the side surface of the resin sealing body.