JP2766086B2 - Heat sink manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a heat sink on which a semiconductor element is mounted.

[0002]

2. Description of the Related Art A semiconductor device is mounted on a heat sink to dissipate heat generated during operation.
In particular, this heat sink is a particularly important component in a light emitting element or the like made of a compound semiconductor such as GaAs because of its large heat generation.

Conventionally, Cu,
Mo, metal materials composed of alloys thereof, AlN, cB
Although ceramic materials such as N and semiconductor materials such as Si are used, metal materials are particularly suitable for practical use from the viewpoint of thermal conductivity, workability, and price.

[0004]

However, in the case of a heat sink material using a metal material, a dicing saw, for example, is generally used to cut a plate-shaped chip into a chip having a size suitable for a semiconductor element mounted thereon. In the case where the division is performed by the above, a burr generated at the time of this cutting becomes a problem.

FIG. 3 shows a conventional dicing saw.
FIG. 3 is a sectional view of an element structure showing a divided portion of a divided heat sink material. (31) in the figure indicates the dicing position of the heat sink material, (32) is a divided heat sink, and (3)
3) is a burr generated at the end of the heat sink (32) by being divided by the dicing saw.

[0006] Such burrs cause performance degradation of the semiconductor element mounted on the heat sink. For example, FIG.
As shown in (2), when a semiconductor laser element (43) is mounted on a heat sink (41) having burrs after metallization for soldering so that a junction where a laser is emitted is located near the bottom. Since the semiconductor laser element (43) usually needs to be mounted so that the end face of the element and the end face of the heat sink coincide with each other, the presence of the burrs causes a great inconvenience in setting the position of the semiconductor laser element. Then, the direction of the laser (44) emitted from the semiconductor laser cannot be determined (FIG. 4A). Incidentally, (42) in the figure is a layer formed by the metallization.

If the semiconductor element is arranged so as to avoid the burrs, the laser (43) is not effectively irradiated to the outside (FIG. 4 (b)).

On the other hand, when division is performed by a conventional laser cutting method or the like without using a dicing saw, such burrs do not occur. However, since the formation of the layer by the metallization of the solder material is performed after the division of the heat sink material, it becomes a major obstacle to mass productivity.

Accordingly, an object of the present invention is to provide a method of manufacturing a heat sink that solves the problem caused by such burrs.

[0010]

A feature of the method for dividing a heat sink material according to the present invention is to form a trench region by etching or dicing a predetermined depth from one main surface of the heat sink material; Metallizing the surface of the heat sink material with a solder material; and dicing the inside of the trench region with a width smaller than the trench width of the trench region to divide the heat sink material.

[0011]

By performing etching or dicing at a predetermined depth from one main surface of the heat sink material, a trench having a predetermined width is formed on the surface of the heat sink material.

Then, in a later step, the inside of the trench region is diced with a width smaller than the trench width of the trench region, and the heat sink material is divided.

In the following, regarding these two steps, the former is referred to as half dicing, and the latter is referred to as full dancing.

According to the dividing method of the present invention, since the burrs generated on the surface of the heat sink material, which are conventionally generated, are formed at the bottom in the trench region, it is not necessary to remove them by polishing.

If a method using a laser is used for the half dicing, no burrs are generated in the half dicing process, so that the mounting position of the semiconductor element can be kept extremely flat.

Further, when a method using a dicing saw is used as the half dicing, burrs are generated. However, since the heat sink material is not yet divided in this step, polishing of the burrs impairs mass productivity. It can be easily performed without any additional steps.

[0017]

FIG. 1 is a sectional view of an element structure for each step for explaining a method of manufacturing a heat sink according to the present invention.

In the step shown in FIG. 1A, half dicing of a predetermined depth is performed on one main surface (2) of a plate-like heat sink material (1) made of Cu having good thermal conductivity. In this example,
Since the half dicing by the laser is used, the burrs as described above do not occur.

The thickness of the copper used in the examples was 0.3 m.
m, the trench width (w) of the trench region (3) formed by the half dicing is 100 μm, and the depth (d) is 1
50 μm.

In the step shown in FIG. 2B, a solder material 4 made of indium is metallized on the entire surface of the heat sink material.

Then, in the step shown in FIG. 3C, a width smaller than the trench width (w) in the trench region (3), in the embodiment, 30
Full dicing is performed with a width of μm to divide the heat sink material. By performing this full dicing, burrs (5) are generated at the bottom in the trench region, but since this portion is not used as a mounting portion of a semiconductor element, it is necessary to remove burrs by polishing. There is no.

In this embodiment, a laser is used for the half dicing. However, when this is performed by dicing with a dicing saw, burrs are generated. However, in the present invention, it is not always necessary to remove the burrs by polishing. That is, since the burrs generated by the half dicing have a shallower dicing depth than the conventional burrs, the burrs are small without generating large burrs as conventionally seen.

Therefore, in such a case, it is sufficient to determine whether or not to remove the burrs according to the condition of use of the heat sink. However, even when the removal is performed, the heat sink material is still divided. Since it is not in the state,
The heat sink material can be integrally polished, and burrs can be easily removed.

FIG. 2 shows an element structure diagram when a semiconductor laser element (22) is mounted on a heat sink (21) manufactured by the manufacturing method of the embodiment. As shown in the figure, the semiconductor laser device is not affected by the burrs.
That is, it can be mounted on a portion where the end face of the semiconductor laser element (22) and the end face of the heat sink coincide with each other. Does not hinder laser light irradiation.

Further, the present invention is not limited to a semiconductor laser device or the like, and it goes without saying that the present invention can be used for a heat sink or the like for radiating a semiconductor device such as a power transistor.

[0026]

According to the dividing method of the present invention, since the burrs generated on the surface of the heat sink material, which are conventionally generated, are formed at the bottom in the trench area, it is not necessary to remove them by polishing.

Also, if a laser method is used for the half dicing, no burrs are generated in the half dicing process, so that the mounting position of the semiconductor element can be kept extremely flat.

Further, when a method using a dicing saw is used as the half dicing, burrs are generated. However, since the heat sink material is not yet divided in this step, polishing of the burrs impairs mass productivity. It can be easily done without.

[Brief description of the drawings]

FIG. 1 is a sectional view of an element structure for explaining a manufacturing method of the present invention.

FIG. 2 is a cross-sectional view of an element structure when a semiconductor element is mounted on a heat sink manufactured by the manufacturing method.

FIG. 3 is a sectional view of an element structure showing a shape of a chip of a heat sink manufactured by a conventional method of manufacturing a heat sink.

FIG. 4 is a cross-sectional view of an element structure when a semiconductor element is mounted on a heat sink manufactured by a conventional manufacturing method.

[Explanation of symbols]

 (1) Heat sink material (2) Main surface (3) Trench area (4) Solder material (5) Burr

Claims (1)

(57) [Claims] 1. A step of forming a trench by etching or dicing a predetermined depth from one main surface of a heat sink material, a step of metallizing a surface of the heat sink material with a solder material, Dicing the interior of the trench region with a width smaller than the trench width and dividing the heat sink material.