JPH098188A - Heat spreader - Google Patents

Abstract

PURPOSE: To provide a heat spreader which has a high cooling capability and in which an insulating film, whose characteristics such as an insulating property, a heat-resistant property, a heat-resistant fatigue property, a solvent-resistant property and the like are excellent, is formed on the surface at low costs. CONSTITUTION: A heat spreader 1 for a semiconductor device is covered with a plate 3 which is composed of copper or of an alloy composed mainly of copper and with an insulating layer 4 in which at least the heat dissipating face of a fin part 5 has been formed on the surface and which uses a solder resist film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a heat spreader as a heat dissipation member for dissipating heat from a semiconductor element into the atmosphere in an electronic device such as a ceramic package used in a semiconductor device.

[0002]

2. Description of the Related Art In an electronic device such as a ceramic package for a semiconductor device, a semiconductor element that operates at high speed generates a large amount of heat, and therefore a heat spreader is used as a heat dissipation member for efficiently dissipating the generated heat. in use.

Aluminum materials are generally used in conventional heat spreaders. In order to use the aluminum material alone in the form of a plate or to further improve the heat dissipation ability on the plate-shaped aluminum material. In addition, a fin-shaped aluminum material is used by being bonded with an adhesive having good thermal conductivity.

In addition, an insulating layer is formed on the surface of the aluminum material used for these heat spreaders by anodizing in order to electrically insulate and secure safety such as heat resistance and heat fatigue resistance. , When forming this insulating layer, in order to give a high-grade feeling to the heat spreader while giving high heat radiation ability, alumite colored in black close to a perfect black body is preferred and widely used. .

However, with the recent increase in speed and output of electronic devices, the power demands of the electronic devices have increased, and the heat dissipation capability of the heat spreader made of an aluminum material has become insufficient.

In addition, when a fin-shaped aluminum material is used by being adhered to a plate-shaped heat spreader in order to improve heat dissipation characteristics, the package inevitably becomes large. It was

In order to improve this heat dissipation ability, it is necessary to use a heat spreader made of copper or an alloy material containing copper as a main component, which has significantly higher heat radiation ability (cooling ability) than aluminum material. Is effective, but it is difficult to form, for example, a black insulating film having excellent properties such as insulation, heat resistance, heat fatigue resistance, and solvent resistance on the copper surface layer.

[0008]

DISCLOSURE OF THE INVENTION The present invention has a heat spreader having a high cooling capacity and an insulating film formed on the surface at a low cost, which has excellent properties such as insulation, heat resistance, heat fatigue resistance, and solvent resistance. The purpose is to provide.

[0009]

Means for Solving the Problems According to the present invention, the surface of copper or an alloy containing copper as a main component is pickled, or buffing is used to clean the surface, and then screen printing is performed. Layer formed on the surface of at least the heat radiation surface of the plate of copper or copper alloy or at least the heat radiation surface of the fin portion processed into a fin shape by the electrostatic spray coating method, etc. It is formed by a solder resist film.

[0010]

[Function] Copper has a thermal conductivity of about 400 W / m · K,
Since it has a thermal conductivity about twice that of aluminum, it can greatly improve the heat dissipation ability as compared with the conventional aluminum heat spreader.

The plate thickness of the copper or copper alloy used as the heat spreader for the semiconductor device according to the present invention is determined by the heat dissipation design of the electronic device to be mounted, but is usually about 0.3 to 1.5 mm. is there. The thickness of the solder resist film as an insulating layer formed on the heat dissipation surface of copper or copper alloy is 5 to 10 μm, and its color is black in order to enhance the heat radiation ability.

To bond the electronic device or semiconductor package to the heat spreader according to the present invention, an adhesive containing fine particles of AlN or the like having good thermal conductivity is used to reduce the thermal resistance, or tin, copper or the like is used. A metal solder such as an alloy is used. As a result, good thermal conductivity can be obtained even at the joint portion.

Further, in order to improve the heat dissipation ability, a plate of copper or copper alloy processed into a fin shape can be used by adhering it to a plate-shaped heat spreader or electronic device or package. in this case,
Inevitably the package will be larger, but the heat dissipation capability will be better than that of a single plate-shaped heat spreader.

[0014]

【Example】

(Embodiment 1) FIG. 1 shows a semiconductor package 2 having a plate-shaped heat spreader 1 according to the present invention. The heat spreader 1 is a flat copper plate 3 for heat dissipation and cooling.
And an insulating layer 4 made of a solder resist film formed on one of the heat dissipation surfaces.

In the heat spreader 1, the other surface of the plate 3 has a high thermal conductivity in which AlN fine particles are contained in the upper surface of the ceramic case 5 and the surface of the LSI chip 6 housed in the ceramic case 5. They are adhered to and integrated with a type of polymeric thermoplastic adhesive 7.

The LSI chip 6 is electrically connected to one end of the lead frame 8 by a lead wire 9 inside the ceramic case 5. The lead frame 8 is
It is fixed to the ceramic case 5 by an insulating material 10.

The heat radiation / cooling plate 3 is a copper plate having a thickness of 1 mm. The surface of the copper plate is cleaned by a wet buffing method so that the surface contact with the LSI chip 6 is good and the bond with the insulating layer 4 is good. After that, a black epoxy solder resist, for example, is applied to the heat dissipation surface of the copper plate 3 by a screen printing method to form the insulating layer 4 of the solder resist film.

Next, the copper plate 3 coated with the solder resist film is placed in a rack-conveying electric furnace and heated at 130 ° C. for 1 hour.
By heating for 0 minutes and thermosetting,
Provides insulation, heat resistance, heat fatigue resistance, and solvent resistance. After that, by punching, as external dimensions,
A plate-shaped heat spreader 1 having a length and width of 30 × 30 mm is prepared.

The semiconductor package 2 using the heat spreader 1 according to the present invention has good heat dissipation characteristics. Here, the characteristics of the solder resist film as the insulating layer 4 are as shown in Table 1 below.

[0020]

[Table 1]

(Embodiment 2) FIG. 2 shows an example of a semiconductor package 2 in which a heat spreader 11 processed into a fin shape is further attached to a plate 3. The board 3 is manufactured as the same as that of the first embodiment, and includes the LSI chip 6 and the TA.
A ceramic case 13 in which B (tape automated bonding) 12 is incorporated is adhered using a high thermal conductivity type polymer thermoplastic adhesive 7 containing AlN fine particles.

On the upper surface of the plate 3, the heat spreader 11 processed into a fin shape is provided with the lead alloy solder 14.
Has been fixed by. The fin-shaped heat spreader 11 is formed by using a copper material, and the fin portion 15 as a heat dissipation surface formed on the outer peripheral surface of the cylindrical body is coated with a black epoxy solder resist by an electrostatic spray coating method. An insulating layer 16 made of a film is formed. The semiconductor package 2 using this heat spreader 11 is
The heat dissipation property is better than that of the example shown in the first embodiment.

[0023]

By using the heat spreader according to the present invention, it is possible to manufacture a semiconductor device having an extremely excellent heat dissipation property due to the excellent heat radiation ability of copper or an alloy containing copper as a main component. It is possible to inexpensively provide a semiconductor device having a heat dissipation capability that can sufficiently cope with an increase in the amount of heat generated due to higher output and higher speed calculation.

Further, a solder resist film as an insulating layer can be easily formed on the surface of copper or an alloy containing copper as a heat dissipation surface by a printing or painting method, whereby the function required for the heat spreader, that is, Functions such as insulation, heat resistance, heat fatigue resistance and solvent resistance can be secured. Moreover, by selecting the coloring of the epoxy-based solder resist film, for example, a black insulating layer having good heat radiation ability can be formed. Therefore, a plate-shaped black heat spreader or fin of copper or an alloy containing copper as a main component is formed. It is possible to provide a black heat spreader that is processed into a shape.

[Brief description of drawings]

FIG. 1 is a sectional view of a heat spreader according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a heat spreader according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Heat Spreader 2 Semiconductor Package 3 Plate 4 Insulation Layer 5 Ceramic Case 6 LSI Chip 7 Adhesive 8 Lead Frame 9 Lead Wire 10 Insulation Material 11 Heat Spreader 12 TAB 13 Ceramic Case 14 Lead Alloy Solder 15 Fin Part 16 Insulation Layer

Claims (3)

[Claims] 1. A heat spreader for a semiconductor device, wherein at least a heat radiation surface of a plate made of copper or an alloy containing copper as a main component is covered with an insulating layer formed on the surface of the plate. Characteristic heat spreader. 2. A heat spreader for a semiconductor device, wherein the heat spreader is made of copper or an alloy containing copper as a main component, and the fin-shaped heat dissipation surface of at least the fin portion is formed on the surface of the fin portion. A heat spreader characterized by being covered by layers. 3. The heat spreader according to claim 1, wherein the insulating layer is a solder resist film.