JPH08316381A - Manufacture of heat sink for semiconductor package - Google Patents

Abstract

PURPOSE: To mass produce high quality heat sink by sustaining the material in hooped state even after it is deformed through rolling so that any type of continuous plating can be applied thereto. CONSTITUTION: A flat bar 14 is rolled by means of a roll 11 provided with holes 12 at a predetermined interval on the periphery thereof and a paired flat roll 13. Consequently, a deformed bar 17 having thick plate parts 15 not subjected to rolling because of the hole and a rolled thin plate part 16 on the periphery thereof is produced continuously. The deformed bar 17 is then passed through a continuous plating bath. Since the material is sustained in hooped state even after it is shaped roughly by primary machining, the material can be plated continuously. This method can mass produce a low price high quality heat sink as compared with piece plating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a heat sink for a semiconductor package for absorbing and dispersing heat energy generated by a semiconductor chip, and more particularly to an improved method of plating a surface.

[0002]

2. Description of the Related Art In LSI logic packages such as QFP, the required power consumption is increased and the problem of heat dissipation is becoming more important with the rapid progress of high density and high speed. Therefore, a package structure considering heat dissipation is being studied.

FIG. 3 shows an example of a package structure in consideration of heat dissipation. FIG. 3A shows a heat sink 2 having a relatively thin plate embedded in the mold resin 1, and the heat sink 2 absorbs the heat of the semiconductor chip 3. FIG. 1B shows a structure in which a radiator plate 2 having a relatively large thickness is embedded in a resin 1 and a part of the radiator plate 2 is exposed outside the package. Therefore, it is possible to cope with a larger amount of heat generation than the structure of FIG. In FIG. 3C, fins 4 are further attached to the heat dissipation plate 2 of FIG. 3B to improve heat dissipation. For the heat dissipation plate 2 used for these, pure copper or copper alloy having high heat conductivity is used from the viewpoint of heat dissipation.

[0004]

Among the heat dissipation plates described above, the heat dissipation plate of the type used in FIG. 3 (b) or (c), which has a high heat dissipation property, has attracted attention. Since a part of the heat sink 2 of that type is exposed outside the package, the adhesion between the heat sink 2 and the resin 1 is important from the viewpoint of reliability. Therefore, the heat dissipation plate 2 is formed in a different shape, a part of the thick plate portion 2a is exposed outside the package, and the thick plate portion 2a is exposed.
By embedding the thin plate portions 2b provided in the four directions around a in the resin 1, the adhesiveness is improved and the moisture entry path is lengthened.

In general, the resin adhesion of copper and copper alloys is not good, so the surface of the heat sink 2 is used by being plated with Ni or the like.

By the way, as a method of manufacturing a heat sink having a different shape having thin plate portions in four directions around the thick plate portion,
First, there is a machining method for cutting a thin plate portion from a flat strip material having a plate thickness of the heat radiating plate. Secondly, there is a pressing method in which a deformed strip having a thick plate portion and a thin plate portion is formed from a flat strip material by press working and then punched into a required size. In both the machining method and the pressing method, when the heat sink is plated, a piece plating method is performed one by one.

However, in both the machining method and the pressing method, when the heat sink is plated, piece plating performed one by one has a problem that the plating cost becomes high. In this respect,
It may be possible to adopt barrel plating, which enables large-scale plating, but barrel plating has problems in surface conditions such as scratches and restrictions on the type of plating.

The object of the present invention is to solve the above-mentioned problems of the prior art and to enable continuous plating of any kind with high quality.
It is to provide a method of manufacturing a heat sink for a semiconductor package suitable for mass production.

[0009]

A method for manufacturing a heat sink for a semiconductor package according to the present invention comprises rolling a flat strip with a roll having holes and a flat roll, and a thick plate portion formed without being rolled by the holes. A profiled strip having a thin plate portion formed by rolling around the profiled profile is formed, and the profiled strip obtained is passed through a continuous plating apparatus to continuously plate the profiled strip.

Further, in the method for manufacturing a heat sink for a semiconductor package according to the present invention, the plated profiled strip is guided to a press machine for further press work, and a thin plate part having a predetermined size is left around the thick plate part. While cutting the piece. In this case, it is preferable that the profiled strips obtained by rolling be made into multiple strips so that multiple pieces obtained by press working can be taken.

[0011]

[Function] First, a flat strip is formed into a deformed strip with a roll having holes. When a flat strip is rolled with a holed roll and a flat roll, a thick plate part is formed in the hole part and a thin plate part is formed in the other part. Is molded into a desired shape.

Next, the profiled strip obtained by rolling is passed through a continuous plating device to apply the required plating to the surface of the profiled strip. At this time, since the rolled material is a hoop strip, plating can be continuously applied.

Then, the plated profiled strip is guided to a press working machine and punched by piece cutting while leaving a thin plate portion of a predetermined size around the thick plate portion to obtain a product.

[0014]

Embodiments of the present invention will be described below. FIG. 1 shows a method of manufacturing a heat sink for a semiconductor package according to this embodiment. The heat dissipation plate manufactured here is shown in FIG. 3 (b) or (c).
This type of heat radiating plate has a modified strip, and the standard material is OFC (oxygen-free copper) having excellent thermal conductivity, but other copper alloys may be used. Plating treatment is required on the surface of the heat sink from the viewpoint of resin adhesion.

First, rough forming by rolling is performed as the primary processing of the flat strip material. For that purpose, the flat strip 14 is rolled by the perforated roll 11 provided with the holes 12 at predetermined intervals on the peripheral surface of the roll and the flat roll 13 paired with the perforated roll 11. Then
A thick plate portion 15 formed without being rolled by the hole 12,
The profiled strip 17 having the thin plate portion 16 formed by rolling around the periphery is continuously formed.

Next, continuous plating is performed. The profiled strip 17 obtained by rolling is passed through a continuous plating device 18 to form the profiled strip 1.
7 is continuously plated. The plating includes Sn-Ni, Ag, Cu, Au plating, etc., in addition to Ni plating.
Since the material is a hoop strip even after the rough forming of the primary processing, it is possible to continuously perform plating. In general, continuous plating has better plating quality than piece plating,
Further, various kinds of plating are possible, and there is an advantage that any plating can be selected according to the purpose. Further, the plating treatment with the hoop material is more cost effective than the piece plating.

Further, as secondary processing, adjustment / punch molding by a press is performed to obtain a product. Plated profiled strip 1
7 is guided to a press machine 19 and punched, and the thick plate portion 1
A piece is cut into a product while leaving a thin plate portion 16 having a predetermined size around the periphery of the product 5.

FIG. 2 shows a heat sink 20 for a semiconductor package having a different shape, which is manufactured as described above.

According to this embodiment, the rough shape is rolled and formed at a high speed by the holed roll of the primary processing, and the secondary processing by the next press is simple size / shape adjustment and piece cutting punching. Therefore, as compared with other manufacturing methods, for example, a method in which all steps are performed by pressing or etching, it can be commercialized at high speed and with high efficiency and is suitable for mass production.

In particular, since the plating is performed in the hoop state, the cost of plating can be reduced, any kind of plating can be applied, and a heat sink having excellent surface quality can be manufactured.

Further, since the commercialized heat sink has a modified cross section, the adhesiveness with the resin is improved, the path of moisture intrusion is extended, and the moisture resistance is also improved. In addition, higher output and higher reliability of the semiconductor package can be realized.

In the above-mentioned embodiment, the case where a single strip is handled has been described, but a wider flat strip is used as the material, and the thick plate portions are arranged in parallel by rolling using a roll with parallel holes. To form a multi-stripe modified strip having
This may be subjected to hoop plating, and a large number of radiator plate products may be taken by pressing.

[0023]

According to the present invention, since the material is a hoop strip even after the profiled strip is formed by rolling, continuous plating is possible, which is cheaper and higher in quality than piece plating, and of any type. Plating is possible.

Further, according to the present invention, since it is roll-formed at a high speed and the press working is a simple piece cutting punching,
High speed compared to the method of performing all steps by pressing or etching,
It can be commercialized with high efficiency and is suitable for mass production.

Further, according to the present invention, a large number of pieces can be taken, which is more suitable for mass production.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a method of manufacturing a heat sink for a semiconductor package according to an embodiment of the present invention.

FIG. 2 is a perspective view of a heat dissipation plate commercialized according to this embodiment.

FIG. 3 is a cross-sectional view showing an example of a semiconductor package in consideration of heat dissipation, FIG. 3A is a type in which a heat dissipation plate is embedded,
(B) is a type in which a part of the heat sink is exposed, and (c) is a type in which fins are further attached to the heat sink.

[Explanation of symbols]

 11 Rolls with Holes 12 Holes 13 Flat Rolls 14 Flat Strips 15 Thick Plates 16 Thin Plates 17 Deformed Strips 18 Continuous Plating Equipment 19 Pressing Machines

Claims (3)

[Claims] 1. A profiled strip having a thick plate portion formed by rolling with a holed roll and a flat roll and not rolled by a hole, and a thin plate portion formed by rolling around it. A method for manufacturing a heat dissipation plate for a semiconductor package, which comprises molding, and passing a profiled strip obtained by the above-mentioned rolling through a continuous plating device for continuous plating. 2. The method for manufacturing a semiconductor package heat dissipation plate according to claim 1, wherein the plated profiled strip is introduced into a press machine and further press-processed to have a predetermined dimension around the thick plate portion. A method for manufacturing a heat sink for a semiconductor package, in which pieces are cut while leaving the thin plate portion. 3. The method of manufacturing a heat sink for a semiconductor package according to claim 2, wherein the profiled strips obtained by the rolling are made into multiple strips, and a large number of pieces obtained by press working are taken. Method for manufacturing heat sink.