JPH0966334A - Manufacture of heat sink for semiconductor package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart excellent productivity without causing increase in cost by intermittently forming a projecting thick plate and punching it out by press working. SOLUTION: A planar base material 4 is inserted between a die roll 2, on the outer circumferential surface of which a recessed part 1B is arranged corresponding to a thick plate part 5 at prescribed spaces apart, and a flat roll 3 with a plain outer circumferential surface. The base material 4 is rolled by the rotation (a) (b) of the rolls 2, 3, so that the thick plate parts 5 are formed. Press working is performed on the roll forming material on which the thick plate part 5 is uncontinuously formed by rolling, making a prescribed size with the material. Then, punching is performed with a thin plate part 6 left around the thick plate part 5. The planar base material is composed of copper, copper alloy or aluminum, for example. Consequently, no cost increase is caused for the equipment and the manufacture.

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 for a semiconductor package, and punches a necessary portion of a roll-formed material in which a convex thick plate portion is continuously formed by rolling. Thus, the present invention relates to a method for manufacturing a semiconductor package heat dissipation plate with improved productivity.

[0002]

2. Description of the Related Art In recent years, as integrated circuits (ICs) and large-scale integrated circuits (LSIs) have become highly integrated, high-speed, and high-powered, heat generation of semiconductor chips has become a problem, and heat generation is a problem. Various semiconductor package structures that have been considered have been proposed.

FIG. 5 is a cross-sectional view of a conventional semiconductor package, in which a heat sink 1 for fixing a semiconductor chip 15 and an adhesive plate fixed to the heat sink 1 are electrically connected to the semiconductor chip 15 by a bonding wire 16. The heat dissipation plate 1, the semiconductor chip 15, the bonding wires 16, and the leads 17 are integrally molded with the molding resin 18 and are configured to have the leads 17.

Among them, copper, copper alloy, aluminum or the like having excellent heat conductivity is used for the heat dissipation plate 1 for promoting heat dissipation of the semiconductor chip 15, and the surface of the heat dissipation plate 1 is taken into consideration in consideration of adhesion with the molding resin. Often plated and used.

FIG. 5 (a) shows a package structure having a heat sink 1 under the semiconductor chip 15 and leads 17 and having a 2 W structure.
It is possible to cope with the heat generation of the semiconductor chip to some extent. (b)
Is a heat sink 1 having a convex cross section on the surface of the molding resin 18.
The package structure in which the heat dissipation surface 22 is exposed has a larger allowable amount of heat generation than the package structure of (a), and can cope with the heat generation of the semiconductor chip up to about 5 W.

FIG. 5C shows a package structure in which the heat radiation fins 19 are fixed to the heat radiation surface 22 of the heat radiation plate 1 of the structure shown in FIG. 5B. By mounting the heat radiation fins in this way, the heat radiation performance of the package is further enhanced. It is possible to cope with the heat generation of the semiconductor chip of 10 W or more.

FIG. 6 is a perspective view of the heat radiating plate 1 having the convex cross section packaged in FIGS. 5 (b) and 5 (c). The thin plate portion 21 having a uniform thickness is continuously provided around the thick plate portion 20.

In the method of manufacturing the heat dissipation plate 1 shown in FIG. 6 described above, in addition to the method of individually manufacturing by the cutting process, the plate member is rolled by a rolling roll having a plurality of recesses along the peripheral surface. The method disclosed in Kaihei 5-115938 has been proposed by the applicant.

[0009]

However, according to the conventional method for manufacturing a heat sink for a semiconductor package, a large processing load is required to form a thin plate portion around a thick plate portion by rolling, and a large press machine is used. Is required. Generally, since a press machine with a large processing load has a low processing speed, it is difficult to continuously manufacture the heat sink at a high speed. Therefore, an object of the present invention is to provide a method for manufacturing a heat sink for a semiconductor package, which is excellent in productivity without increasing the cost required for equipment and manufacturing.

[0010]

According to the present invention, in order to provide excellent productivity without increasing the cost required for equipment and manufacturing, concave portions corresponding to the dimensions of the thick plate portion are arranged on the outer peripheral surface at predetermined intervals. The flat plate material is sandwiched between the first rolling roll and the second rolling roll having a flat outer peripheral surface, and the flat plate material is rolled by rotating the first rolling roll and the second rolling roll. To form a rolled formed material having intermittently a convex thick plate portion based on a concave portion on one surface, and by pressing the rolled formed material in which the thick plate portion is intermittently formed by rolling a predetermined Provided is a method for manufacturing a heat sink for a semiconductor package, which is configured such that after the size is set, a punching process is performed in which a thin plate portion is left around a thick plate portion.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A method for manufacturing a heat sink for a semiconductor package of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an example of a manufacturing apparatus of a heat sink for a semiconductor package according to the present invention, in which a die roll 2 having recesses 1B arranged at predetermined intervals on the outer peripheral surface according to the dimensions of the thick plate portion is provided. , A flat plate material 4 made of copper, a copper alloy, aluminum, or the like, which is inserted between the flat rolls 3 having flat outer peripheral surfaces in the direction of the arrow A, rotates the rolls 2, 3 a,
the surface of the die roll 2 contacting the die roll 2
The thick plate portion 5 is formed by B.

On the other hand, a flat portion 1A provided between the recesses 1
Forms a continuous thin plate portion 6 with the thick plate portion 5 by rolling. An expanded portion 7 is formed in the width direction by the plastic deformation of the flat plate material 4 at a position where the thick plate portion 5 is formed by rolling by the rolls 2 and 3, and the thick plate formed in a convex shape with the expanded portion 7 is formed. A rolled formed material 8 in which the portion 5 and the thin plate portion 6 are continuously provided is formed.

When the surface of the heat sink 1 is plated in order to improve the adhesion with the mold resin, the above-mentioned rolled molded material 8 may be plated. In this case, since the continuous thick plate portion 5 and the thin plate portion 6 can be plated, the labor and cost required for plating can be reduced.

FIG. 2 shows a cross-sectional view in the length direction of the rolled formed material 8 in the punching process of punching the heat dissipation plate 1 from the rolled formed material 8, and the rolled formed material 8 placed on the lower die 9 is shown.
An upper die 11 having a recess 10 conforming to the shape of the thick plate portion 5
By punching from the top to the bottom with
Is cut into a predetermined size. At this time, since the thick plate portion 5 is held by the concave portion 10, deformation of the heat radiating surface and the back surface of the heat radiating plate 1 that is punched out is prevented.

Further, in the manufacturing process of the rolled formed material 8 in FIG. 1, depending on the rolling conditions, there is a slight bending or thickness in the plate thickness direction from the rolling process of the thin plate portion 6 to the rolling process of the thick plate portion 5 and the expanded portion 7. A recess may be formed on the back surface of the plate portion 5. FIG. 3 shows a shaping die 12 that simultaneously presses the expanded portion 7 and the thick plate portion 5. By pressing the rolled formed material 8 placed on the flat plate 13 with the shaping die 12 with a relatively small processing load. By shaping the above-mentioned bends and dents and then punching, it is possible to improve the processing accuracy of the thick plate portion 5 and the thin plate portion 6. Further, it is also possible to perform shaping by pressing only on a portion that is likely to be deformed.

Further, after the shaping step of shaping the bending and dent of the rolled formed material 8 described above, the step of punching out the heat dissipation plate 1 may be performed by the same press device.

The method for manufacturing the above-mentioned heat sink for a semiconductor package will be described below by listing specific numerical values.

First, an oxygen-free copper annealed material having a plate thickness of 1.63 mm and a width of 28 mm is rolled by the die roll 2 and the flat roll 3 shown in FIG. A rolled formed material 8 having a plate thickness of 1.6 mm and dimensions of 20 × 20 mm was manufactured. The total width of the rolled formed material 8 is 28.
3 mm, 32 mm at the extension 7. The concave portion 1B of the mold roll 2 is 20 × 20 mm, the depth is 0.8 mm, and the flat portion 1A
Are separated by 25 mm, and the side surface of the concave portion 1B is slightly tapered.

This rolled material 8 was divided into two parts, and one surface was plated with Ni having a thickness of 2 μm by a continuous plating device. The other rolled material 8 remains unchanged.

Next, the above-mentioned rolled forming material 8 is placed on the lower mold 9 shown in FIG. 2, and the upper mold 11 is moved downward from above.
Then, the expansion portion 7 was punched so that a thin plate portion of 2 mm was left around the thick plate portion 5.

By this punching process, the thin plate portion 6 has a plate thickness of 0.8 mm, the thick plate portion 5 has a plate thickness of 1.6 mm, and a dimension of 20 × 20 mm.
A heat sink 1 having a total width of 24 mm was manufactured by. After punching by the press, the slight warpage in the sheet thickness direction that had remained in the rolled formed material 8 was substantially eliminated.

A concave portion 1B is formed with a depth of 10.2 × 10.2 mm and a depth of 0.8 mm, and a plate thickness of 1.5 mm is formed by a die roll 2 and a flat roll 3 which are separated by a flat portion 1A having an interval of 25 mm.
Oxygen-free copper annealed material with a total width of 28 mm has a thickness of the thin plate portion 6 of 0.7.
Rolled to 4 mm. The total width of the obtained rolled formed material 8 is 28 mm in the thin plate portion 6 and 31 mm in the expanded portion 7.
Having. In the thick plate portion 5, a slight increase in thickness was observed in the peripheral portion and the center was slightly depressed, but the average plate thickness was 1.5.
It was 1 mm. Further, in the thin plate portion 6, a slight wavy deformation occurred at the edge portion.

This rolled material 8 is placed on the flat plate 13 shown in FIG. 3, and the size of the opening corresponding to the thick plate portion 5 is 10 × 10 m.
Upper mold 12 with m and depth of 0.7 mm and a substantially right-angled hole
Then, the thin plate portion 6 was shaped so that the thin plate portion 6 had a plate thickness of 0.7 mm and the thick plate portion 5 had a plate thickness of 1.4 mm. In addition, the processing range of the thin plate portion 6 was 8 mm width around the thick plate portion 5.

By this shaping process, the deformation generated at the edge of the thin plate portion 6 in the rolled formed material 8 is eliminated, and the dent at the center of the thick plate portion 5 is also eliminated.

Next, the rolled formed material 8 which has been subjected to shaping processing
2 is placed on the lower die 9 shown in FIG. 2 and punched by the upper die 11 from the upper side to the lower side, and the expansion portion 7 is left so as to leave a thin plate portion of 7 mm around the thick plate portion 5. Punched out.

By this punching process, the thin plate portion 6 has a plate thickness of 0.7 mm, the thick plate portion 5 has a plate thickness of 1.4 mm, and a dimension of 10 × 10 mm.
A heat sink 1 having a total width of 24 mm was manufactured by.

FIG. 4 shows a state in which the uncut portion 14 is provided during punching of the rolled material 8 by the lower die 9 and the upper die 11 and the other portions are cut. By punching out the roll-formed material 8 in this way, the heat dissipation plate 1 does not come apart, and the handling property in the subsequent process is improved. In addition, when the surface of the heat sink 1 is plated, the work is facilitated and the area where the plating is attached is expanded.

[0029]

As described above, according to the method for manufacturing a semiconductor package heat dissipation plate of the present invention, the first rolling roll having the concave portions arranged on the outer peripheral surface at predetermined intervals according to the dimensions of the thick plate portion, A flat plate material is sandwiched between a second rolling roll having a flat outer peripheral surface, and the flat plate material is rolled by rotating the first rolling roll and the second rolling roll, thereby forming a recess on one surface. After forming a rolled formed material having convex thick plate portions intermittently, and pressing the rolled formed material in which the thick plate portions are intermittently formed by rolling to a predetermined size, the thick plate portion is formed. Since the punching process is performed to leave the thin plate portion around the periphery of, the excellent productivity can be provided without increasing the cost required for equipment and manufacturing.

[Brief description of drawings]

FIG. 1 is a perspective view showing one manufacturing process of a heat sink for a semiconductor package according to the present invention.

FIG. 2 is a cross-sectional view showing a punching process of a heat dissipation plate.

FIG. 3 is a cross-sectional view showing a step of shaping a rolled material.

FIG. 4 is a perspective view showing another method for punching a rolled formed material.

FIG. 5 is a cross-sectional view showing a conventional semiconductor package.

FIG. 6 shows a perspective view of a conventional heat sink for a semiconductor package.

[Explanation of symbols] 1 heat sink 1A flat part 1B recessed part 2 type roll 3 flat roll 4 flat plate material 5,20 thick plate part 6,21 thin plate part 7 expanded part 8 rolled forming material 9 lower mold 10 recessed part 11 upper mold 12 Shaping Mold 13 Flat Plate 14 Uncut Part 15 Semiconductor Chip 16 Bonding Wire 17 Lead 18 Mold Resin 19 Radiating Fin 22 Radiating Surface

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01L 23/29 H01L 23/36 A (72) Inventor Yoshiki Shinohara 3550 Kidayomachi, Tsuchiura City, Ibaraki Prefecture Hitachi Cable Co., Ltd. Tsuchiura factory

Claims (3)

[Claims] 1. A convex section having a thick plate portion having a heat radiation surface and a thin plate portion having a thickness smaller than that of the thick plate portion around the thick plate portion is formed, and the heat radiation is performed after molding. A method of manufacturing a heat sink for a semiconductor package, the surface of which is exposed to the surface of a molding resin, comprising: a first rolling roll having concave portions arranged on the outer peripheral surface at predetermined intervals according to the dimensions of the thick plate portion; and a flat outer periphery. A flat plate material is sandwiched between a second rolling roll having a surface, and the flat plate material is rolled by rotating the first rolling roll and the second rolling roll to form the concave portion on one surface. After forming a rolled formed material having the convex thick plate portion intermittently based on, after the rolled molded material in which the thick plate portion is intermittently formed by rolling is pressed into a predetermined size Leaving the thin plate portion around the thick plate portion A method of manufacturing a heat sink for a semiconductor package, which comprises performing a punching process. 2. The method for manufacturing a heat dissipation plate for a semiconductor package according to claim 1, wherein the press working shapes the thick plate portion and the thin plate portion of the rolled formed material at the same time. 3. The method for manufacturing a heat dissipation plate for a semiconductor package according to claim 2, wherein the punching process is partially punching by leaving an uncut portion in the thin plate portion.