JPH11145352A - Heat spreader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high cooling capability by forming a chemically treated roughened surface on at least a heat dissipating surface of a plate composed of copper or alloy, whose main component is copper, and treating the surface to be black. SOLUTION: A heat spreader 1 is constituted of a plate 3 of a copper member and a roughened surface 4, which is subjected to chemical treatment on the main plane of the plate 3. A plastic substrate 5, on which a wiring layer is arranged and a semiconductor element 6 accommodated in the substrate 5 are bonded on a surface facing a heat dissipating surface of the plate 3, by using a high polymer thermoplastic adhesive agent 7 of high thermal conductivity in which AlN fine particles are contained, and they are collectively formed in an integral body. Since thermal conductivity of copper is higher than that of aluminum, heat dissipating capability can be improved greatly. Since the roughed surface 4 is turned into CuO by alkaline treatment and simply blacked, thermal radiation capability can be improved. Since the high thermal conductivity adhesive agent 7 is used for bonding the semiconductor element 6 and the heat spreader 1, good thermal conductivity can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat spreader as a heat dissipating member for dissipating heat from a semiconductor element to the atmosphere in a semiconductor device.

[0002]

2. Description of the Related Art In a semiconductor device on which a semiconductor element such as an LSI is mounted, a semiconductor element operating at a high speed generates a large amount of heat, and a heat spreader is used as a heat radiating member to efficiently release the generated heat. in use.

[0003] Aluminum materials are generally used in conventional heat spreaders. In order to use the aluminum material alone in a plate shape or to further improve the heat dissipation capability on the plate-like aluminum material. A fin-shaped aluminum material is used by bonding it with an adhesive having good heat conductivity.

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

However, with the recent increase in speed and output of semiconductor devices, the heat dissipation capability of a heat spreader made of an aluminum material has become insufficient.

In order to improve the heat dissipating ability, a heat spreader made of copper or an alloy material containing copper as a main component, which has a significantly higher heat radiating ability (cooling ability) than aluminum material, is used. However, copper or a material containing copper as a main component (hereinafter, abbreviated as a copper-based material) easily discolors on the surface and cannot be used as it is.

In order to prevent surface oxidation of copper-based materials,
It is conceivable to perform a plating process such as Ni plating on the surface. However, in the plating process, it was difficult to perform a surface treatment exhibiting black, which is preferred as a package color of an electronic device. Also, when injecting resin into the package and packaging, the Ni-plated surface has poor adhesion to the resin,
Problems such as generation of voids have occurred.

[0008]

SUMMARY OF THE INVENTION The present invention provides a heat spreader made of a copper-based material having a high cooling capacity, the surface of which is treated black, and which has excellent adhesion to a package resin. The purpose is to do.

[0009]

In the heat spreader of the present invention, at least a heat-radiating surface of a plate made of copper or an alloy containing copper as a main component is formed with a roughened surface by a chemical treatment. Further, the roughened surface is made of CuO so as to be black.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The thickness of copper or a copper alloy used as a heat spreader for a semiconductor device according to the present invention is determined by a heat dissipation design of a semiconductor device to be mounted. It is about 1.5 mm.

[0011] Copper has a thermal conductivity of about 400 W / m · K, which is about twice as high as that of aluminum. Ability can be improved.

The roughened surface formed on the heat radiating surface of copper or a copper alloy is preferably black in order to increase the heat radiation ability. In the present invention, by making the roughened surface CuO by alkali treatment,
It can be easily blackened. In addition, since the roughening process is performed by a chemical process, it is possible to simultaneously perform the roughening process on a surface other than the heat radiation surface. Therefore, when the main plane other than the heat radiation surface is also subjected to the roughening treatment, it is possible to improve the adhesion to the package sealing resin when injecting the resin into the package and packaging.

For joining the semiconductor element and the heat spreader, AlN having good thermal conductivity is used to reduce the thermal resistance.
A highly heat-conductive adhesive containing fine particles such as, or a metal solder such as a tin or copper alloy is used. Since the heat spreader of the present invention has excellent bonding properties with the above-mentioned adhesive and metal solder, good thermal conductivity can be obtained even at the bonding portion.

[0014]

An embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a plate-like heat spreader 1 according to the present invention.
FIG. 1 is an example of a cross-sectional view of a semiconductor device 2 having the following.

The heat spreader 1 comprises a copper plate 3 and a roughened surface 4 formed on the main plane of the plate. On the surface of the plate 3 facing the heat radiation surface, a plastic substrate 5 provided with a wiring layer and a semiconductor element 6 housed inside the plastic substrate 5 are made of a high thermal conductivity type polymer thermoplastic resin containing AlN fine particles. And is integrated with them.

The semiconductor element 6 is electrically connected to one end of the plastic substrate 5 by a bonding wire 8, and is further electrically connected to a solder ball 9 via a wiring layer in the plastic substrate 5. . The connection surface of the bonding wires 8 of the semiconductor element 6 and the bonding wires 8 are covered with a resin 10 for protection.

In this embodiment, a 1 mm thick copper plate is used as the plate 3.

First, the surface of the copper plate was cleaned by a wet buffing method in order to make good surface contact with the LSI chip 6. Next, 31 g of sodium chlorite
/ L, 15 g / L of sodium hydroxide, and 10 g / L of trisodium phosphate at 95 ° C for 2 minutes to roughen the surface and form a black roughened surface made of CuO. . Finally,
A 30 mm square square plate-like heat spreader 1 was formed by punching.

The semiconductor device 2 using the heat spreader 1 according to the present invention produced as described above has good heat radiation characteristics.

[0020]

By using the heat spreader according to the present invention, a semiconductor device having extremely excellent heat dissipation can be manufactured by the excellent heat radiation ability of copper or an alloy containing copper as a main component. Further, by forming a roughened surface made of CuO on the heat radiation surface of a plate of copper or an alloy containing copper as a main component by chemical treatment, a black heat spreader can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is an example of a sectional view of a semiconductor device using a heat spreader of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat spreader 2 Semiconductor device 3 Board 4 Roughened surface 5 Plastic substrate 6 Semiconductor element 7 Adhesive 8 Bonding wire 9 Solder ball 10 Resin

Claims (2)

[Claims] 1. A heat spreader for a semiconductor device, wherein a roughened surface by chemical treatment is formed on at least a heat radiation surface of a plate made of copper or an alloy containing copper as a main component. . 2. The heat spreader according to claim 1, wherein the roughened surface is made of black CuO.