JPH04268754A - Semiconductor device - Google Patents

Abstract

PURPOSE:To enable a semiconductor device equipped with a heat sink to be enhanced in heat dissipating properties and thermal conductivity between the heat sink and a plastic package and to easily mount the heat sink on the plastic package. CONSTITUTION:A semiconductor device is composed of a plastic package 10 where a semiconductor is housed and a heat sink 18 joined to the plastic package 10, where the heat sink 18 is formed of a metal body 20 high in thermal conductivity, the metal body 20 is bonded to the plastic package through an adhesive agent 26, and a plating 28 is provided to the outer surface of the metal body 20 excluding the joint of the metal body 20 with the plastic package.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a heat sink attached to a plastic package. 2. Description of the Related Art Recently, as semiconductor devices have become faster and have larger capacities, there is a tendency for the power consumption and the amount of heat generated to increase during the operation of semiconductors. For this reason, a technique for attaching a heat sink to a package containing a semiconductor chip has been developed, but there is a need for even better heat dissipation and ease of bonding.

0002

2. Description of the Related Art It has been proposed to attach a metal heat sink to a plastic package in which a semiconductor chip is sealed with resin to radiate heat to prevent the semiconductor chip inside the package from being damaged. In this case, the metal heat sink is fixed to the plastic package by adhesive. Since this metal heat sink is exposed to the outside, it is susceptible to corrosion due to exposure to moisture and dirt.
In order to provide corrosion resistance, the outer circumferential surface of a heat sink is increasingly subjected to plating, chemical conversion treatment, or the like.

0003

However, when the outer peripheral surface of the heat sink is plated, a plating layer is present at the joint between the heat sink and the plastic package. Since the plating surface is hard and smooth, it is difficult for the adhesive to wet the plating layer of the heat sink, resulting in a problem in that the bonding strength of the adhesive between the heat sink and the plastic package is reduced. Also, plating has poor thermal conductivity,
There is a problem in that the conduction of heat from the plastic package to the heat sink is reduced, making it impossible to achieve sufficient heat dissipation performance of the plastic package.

Further, the surface of the conventional plastic package is smooth, and there is no alignment means for attaching a heat sink, and there is no means for increasing the bonding force with the heat sink on the surface of the plastic package. Therefore, when attaching the heat sink, it was necessary to perform positioning using a special jig.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device in which the heat conductivity and heat dissipation between a heat sink and a plastic package are improved, and the heat sink can be easily attached to the plastic package.

[0006]

[Means for Solving the Problems] A semiconductor device according to the present invention includes a plastic package containing a semiconductor chip and a heat sink bonded to the plastic package, and the heat sink is formed of a metal body with good thermal conductivity. , the metal body is bonded to the plastic package with an adhesive, and the outer peripheral surface of the metal body is plated except for the joint with the plastic package.

[0007]

[Operation] In the present invention, the heat sink is plated, but the plating is removed by polishing or the like at the joint of the heat sink to the plastic package. Therefore, the thermal conductivity from the plastic package to the heat sink increases, and the heat dissipation of the plastic package improves. Furthermore, the adhesion between the heat sink and the plastic package due to the adhesive is increased, which not only improves heat dissipation but also improves durability.

[0008] If a structure is adopted in which a concave-convex positioning means is provided at the joint of the plastic package with the heat sink, alignment becomes easy when attaching the heat sink to the plastic package, and the semiconductor chip inside the plastic package is easily aligned. The position of the heat sink can be adjusted accurately. Furthermore, since the uneven positioning means widens the bonding area between the heat sink and the plastic package, it is possible to achieve improved heat dissipation and improved durability due to the increased contact area.

[0009]

Embodiment Referring to FIG. 1, in a first embodiment of the present invention, a semiconductor chip 12 of a semiconductor device is comprised of a plastic package 10 sealed with resin 14, and leads 16 extend from the side of the plastic package 10. ing. Leads 16 are provided, for example, in an arrangement known as DIP or SIP.

The heat sink 18 is formed of a metal body 20 made of copper or the like having good thermal conductivity. The metal body 20 extends in the longitudinal direction of the plastic package 10 and includes legs 22 and heat dissipating fins 24 . The legs 22 of the metal body 20 are adhered to the top surface of the plastic package 10 with an adhesive 26. The outer peripheral surface of the metal body 20 is plated 28 to prevent corrosion. This plating 2
8 is applied to almost the entire outer peripheral surface of the metal body 20,
Only the portion where the metal body 20 joins the plastic package 10 is not plated. That is, only the bottom surfaces of the legs 22 of the metal body 20 are not plated.

When plating the metal body 20, it is possible to leave only the bottom surface of the legs 22 of the metal body 20 unplated; however, in this embodiment, the metal body 2
After plating is applied to the entire outer peripheral surface of the leg 22, the plating on the bottom surface of the leg 22 is removed by a mechanical or chemical method. In this way, by removing the plating on the bonding surface of the heat sink 18 to the plastic package 10, the obstacle of plating is removed, so the heat conductivity from the plastic package 10 to the heat sink 18 is increased, and the heat dissipation performance of the plastic package 10 is improved. improves. Further, by mechanically removing the plating on the bottom of the legs 22 of the metal body 20, the legs 22 are roughened.
The bonding force between the bottom surface of the plastic package 10 and the adhesive 26 increases.

FIG. 2 shows a second embodiment of the present invention. Similar to the first embodiment, a semiconductor device has a semiconductor chip 12 covered with resin 1.
4, and a lead 16 extends from the side of the plastic package 10. The heat sink 18 consists of a metal body 20 including legs 22 and radiation fins 24.
Plating 28 is applied to the outer peripheral surface of the metal body 20 to prevent corrosion, and this plating is removed from the bottom surface of the legs 22 of the metal body 20.

Furthermore, an uneven positioning means is provided at the joint portion of the plastic package 10 with the heat sink 18. This positioning means is used to position the plastic package 10 during resin molding of the plastic package 10.
It consists of a convex portion 30 provided on the surface of. On the other hand, a recess 32 is provided on the bottom surface of the leg 22 of the metal body 20. These convex portions 30 and concave portions 32 are formed in a fitting relationship, and the heat sink 18 is attached to the plastic package 1.
By fitting the concave portion 32 into the convex portion 30 when attaching the heat sink 1 to the semiconductor chip 12 in the plastic package 10, alignment becomes easy.
8 can be adjusted accurately.

Furthermore, the fitting relationship between the convex portion 30 and the concave portion 32 expands the bonding area between the heat sink 18 and the plastic package 10, thereby improving heat dissipation and durability by increasing the contact area. can. adhesive 2
6 is applied to an area covering at least the surface and side surfaces of the convex portion 30.

FIG. 3 shows a third embodiment of the present invention, which has substantially the same configuration as the second embodiment. That is, a heat sink 18 made of a metal body 20 including legs 22 and radiation fins 24 can be attached to a plastic package 10 in which a semiconductor chip 12 is sealed with resin 14. Plating 28 is applied to the outer peripheral surface of the metal body 20 to prevent corrosion.
The bottom surface of the leg portion 22 of No. 0 is removed.

Furthermore, the uneven positioning means of the joint portion of the plastic package 10 with the heat sink 18 is
Recess 3 provided on the surface of plastic package 10
Consists of 4. The legs 22 of the metal body 20 fit into this recess 34.
It is designed to be mated to the Therefore, heat sink 1
8 to the plastic package 10, the legs 22 of the metal body 20 need only be fitted into the recesses 34, and the position of the heat sink 18 can be easily and reliably adapted to the plastic package 10 without using special workers. be able to. In the embodiment, projections 34a are provided on the surface of the plastic package 10, and recesses 34 are provided between these projections 34a.

[0017]

[Effects of the Invention] As explained above, according to the present invention,
It consists of a plastic package containing a semiconductor chip and a heat sink bonded to the plastic package, the heat sink being formed of a metal body with good thermal conductivity, the metal body being bonded to the plastic package with an adhesive, and the heat sink being bonded to the plastic package. The outer circumferential surface of the metal body is plated except for the joints with the plastic package, which improves the heat dissipation of the plastic package and also improves the adhesion between the heat sink and the plastic package due to the adhesive. This allows the heat sink to be easily attached to the plastic package.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a third embodiment of the present invention.

[Explanation of symbols]

10...Plastic package 12...Semiconductor chip 18...Heat sink 20...Metal body 26...Adhesive 28...Plating 30...Protrusion 34... recess

Claims (1)

[Claims] 1. A plastic package (10) containing a semiconductor chip, and a heat sink (18) bonded to the plastic package, the heat sink being formed of a metal body (20) with good thermal conductivity,
A semiconductor device characterized in that the metal body is bonded to the plastic package with an adhesive (26), and the outer peripheral surface of the metal body is plated (28) except for the joint with the plastic package. .