JP2000294697A - Stiffener integrating a heat sink and a method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a stiffener integrating a heat sink that enables high volume production which may not cause residual distortion and deformation and requiring the cutting process after the diffusing process and the etching process. SOLUTION: At least one through-hole is provided to a metal heat sink 1 having at least one flat surface, one surface 1a of the heat sink 1 is pressed to form the recess 2 and the through-hole is filled through the movement of metal part pressed with the press work. The volume of the through-hole filled with the movement of the pressed metal part is set to 0.1 to 1.0 times or preferably to 0.2 to 0.8 times the volume of the metal part located at the recess. Moreover, the distance between the edge of recess and the edge of through-hole provided opposed to the recess is set to 0.4 to 3.0 times or preferably to 0.6 to 1.2 times the distance between the center of through-hole and the edge of through-hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stiffener integrated with a heat sink and a method for manufacturing the stiffener. And a method of manufacturing the same.

[0002]

2. Description of the Related Art Semiconductor packages used in personal computers, mobile phones, and the like continue to be miniaturized and densified.
Semiconductor packages using a flexible printed circuit board or a TAB film for a connection portion between a chip such as a chip and a memory and an external circuit are becoming mainstream.

However, the above-mentioned flexible printed circuit board or TAB film has no rigidity and is liable to be warped, so that it is necessary to reinforce it. There is a need to.

FIGS. 12 and 13 show an example of the above-mentioned conventional semiconductor package. Reference numeral 1 denotes a rectangular copper or copper alloy having one flat surface 1a and the other surface 1b for forming a heat sink integrated stiffener. The heat sink 2 has a rectangular recess formed on the one surface 1a, and the flexible plate 3 has a window hole 3a having the same size as the recess 2 and is fixed to the one surface 1a with an adhesive. Wiring board 4 such as a printed board or TAB film, and 4 is a window hole 3a of the wiring board 3.
A large number of terminal parts formed by printed wiring on the periphery of
Reference numeral 5 denotes a chip such as an IC or a memory fitted in the recess 2 through the window hole 3a and fixed by an adhesive, 6 denotes the same number of terminals as the terminal portions 4 formed on the upper surface of the chip 5, 7 Is a bonding wire for electrically connecting the terminal portion 4 of the wiring board 3 and the terminal 6 of the chip 5, and 8 is a seal for injecting the concave portion 2 to seal the chip 5 and the bonding wire 7 from the outside. The agent 9 is a solder ball provided on an external terminal on the outer edge of the wiring board 3.

In the conventional cavity type heat sink integrated stiffener, a rectangular heat sink 1 having flat surfaces on both sides is put into a mold, a concave portion is formed on one surface by press working, and thereafter, it is released to the periphery. A method of cutting off material, a method of overhanging from one surface to the other surface several times to form a concave portion, and a method of cutting and removing a portion overhanging from the other surface by the overhanging process, Is formed by a method of forming a concave portion by performing an etching process on the surface.

[0006]

However, in the above-described method, the metal corresponding to the volume of the concave portion is pushed into a portion other than the concave portion of the stiffener integrated with the heat sink, and the metal portion is compressed, the residual strain remains, and the heat dissipation is reduced. The flatness of the plate-integrated stiffener may be impaired, and deformation may occur when heated in a chip mounting step or the like.

In the above method, a cutting step is required during the manufacturing process, and mass production in a short time is difficult.

Further, in the method (1), it is necessary to mask a portion other than a portion to be a concave portion before etching.
There are drawbacks that the cost is high and that it is not suitable for mass production in a short time.

The present invention has been made to eliminate the above disadvantages.

[0010]

[Means for Solving the Problems]

According to the method of manufacturing a stiffener integrated with a heat sink of the present invention, at least one through hole is provided in a flat metal heat sink, and one surface of the heat sink including the through hole is pressed. Forming a recess and filling the through-hole with a metal portion moved by the press.

The volume of the through hole portion filled by the movement of the metal portion is 0.1 to 1.0 times, preferably 0.2 to 0.8 times the volume of the metal portion located in the concave portion. It is characterized by the following.

The distance between the edge of the recess and the edge of the through hole facing the edge is 0.4 to 3.0 times the distance between the center of the through hole and the edge of the through hole. , Preferably 0.6
１．２1.2 times.

The heat sink integrated stiffener of the present invention comprises a flat heat sink and a recess formed on one surface of the heat sink, and the width and length of the recess are the width and length of the heat sink. It is characterized in that each of them is 90% or less.

[0015] The thickness of the heat sink at the position of the recess is at least 10% of the thickness of the heat sink.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a method of manufacturing a stiffener integrated with a heat radiating plate according to the present invention, as shown in FIGS. 1 and 2, a rectangular metal heat radiating plate having one and the other surface flat.
Is punched by a press or the like, and one circular through hole 10 penetrating from one surface to the other surface is provided.

Next, the metal heat sink 1 is put into a mold,
From the one surface 1a, the through hole 1 is formed by pressing.
Pressing a predetermined range including 0 to the required depth,
A recess 2 is formed as shown in FIG. 3, and the through hole 10 formed in the heat sink 1 is filled with the metal of the pressed recess 2 as shown in FIG. Let it form.

If the width of the radiator plate 1 is assumed to be A and the length of the radiator plate 1 is assumed to be B due to the problems of mechanical strength and flatness of the stiffener integrated with the radiator plate, the width and the length of the concave portion 2 will be A, B
If the thickness of the radiator plate 1 is C, the thickness of the radiator plate 1 at the concave position is 10% of C.
It is preferable to make the above.

FIG. 4 shows a movement due to the formation of the recess 2.
Let V2 be the volume of the metal in the portion indicated by the dotted line at the top of FIG. 4, and let V1 be the volume of the through-hole portion indicated by the dotted line at the bottom of FIG. Since there is not enough metal to be filled, the through hole cannot be completely filled.

When V1 is less than 0.1 times V2, metal parts other than those filling the through-holes move to parts other than the concave parts 2, thereby deteriorating the flatness of the heat sink integrated stiffener. Or, an excessive residual strain is left as a whole.

Therefore, V1 is 0.1 to 1.0 times V2,
Preferably, it is set in the range of 0.2 to 0.8 times.

As shown in FIG. 5, the distance X between the edge of the recess 2 and the edge of the through hole 10 facing the recess 2 is equal to the distance between the center of the through hole 10 and the edge of the through hole 10. If the distance R is smaller than 0.4 times the distance R, the through-hole 10 may not be filled with the metal part existing between the edge of the recess 2 and the edge of the through-hole 10.

If X is larger than 3.0 times R, the metal portion does not move to the through hole portion but moves to a portion other than the through hole portion to improve the flatness of the heat sink integrated stiffener. It may worsen or leave extra strain on the whole.

Therefore, X is preferably in the range of 0.4 to 3.0 times, preferably 0.6 to 1.2 times R.

A plurality of the through holes 10 may be provided, and the through holes 10 may have an arbitrary shape other than a circular shape.

FIG. 6 shows that the through-hole 10 is rectangular and the number thereof is nine.
Another experimental example of the present invention is shown below.

Further, the heat radiating plate 1 may have an arbitrary shape other than a rectangular shape.

Further, the rolled metal plate may be drawn out, a through hole 10 may be formed in the rolled metal plate, and then pressed to form the concave portion 2 and then cut into an arbitrary shape to form the heat sink 1.

(Experimental example 1)

Thickness 0.7 mm, width 27 mm, length 27 m
A through-hole 10 is formed in the heat-dissipating plate 1 made of oxygen-free copper of m by press punching, and then a part of one surface 1a of the heat-dissipating plate 1 including the through-hole 10 is pressed to be 11 mm long and 11 mm wide.
A recess 2 having a depth of 0.4 mm was formed, and finishing was performed to produce a heat sink integrated stiffener. The shape of the through hole 10 is circular, the number is 13, and the arrangement of the through hole 10 is shown in FIG.
The total volume (V1) of the through-hole portion filled with the metal moved by the press is set to 0.6 times the volume (V2) of the metal portion located in the concave portion 2 to be pressed. The distance (X) between the edge of the through hole 10 facing this edge and the center of the through hole 10 is defined by the distance (X).
2.4 times the distance (R) between the edge and the edge.

As a result of examination after pressing, there was no through hole portion left unfilled. Also, as a result of examining the presence or absence of deformation of the heat sink integrated stiffener after heat treatment at 200 ° C. for 60 minutes,
No deformation was observed.

(Experimental example 2)

A heat sink integrated stiffener was manufactured in the same manner as in Experimental Example 1, and the same test as in Experimental Example 1 was performed. The shape of the through-hole was circular, the number of through-holes was 16, the arrangement of the through-holes was as shown in FIG. 8, the ratio between V1 and V2 was 0.6, and the ratio between X and R was 2.1. There were no through-hole portions left unfilled, and no deformation was observed after the heat treatment.

(Experimental example 3)

A heat sink integrated stiffener was manufactured in the same manner as in Experimental Example 1, and the same test as in Experimental Example 1 was performed. The shape of the through-holes was circular, the number of through-holes was 25, the arrangement of the through-holes was as shown in FIG. 9, the ratio between V1 and V2 was 0.6, and the ratio between X and R was 1.0. There were no through-hole portions left unfilled, and no deformation was observed after the heat treatment.

(Experimental example 4)

A heat sink integrated stiffener was manufactured in the same manner as in Experimental Example 1, and the same test as in Experimental Example 1 was performed. The shape of the through holes was square, the number of the through holes was 25, the arrangement of the through holes was as shown in FIG. 10, the ratio between V1 and V2 was 0.6, and the ratio between X and R was 1.0. There were no through-hole portions left unfilled, and no deformation was observed after the heat treatment.

(Comparative Example 1)

A heat sink integrated stiffener was manufactured in the same manner as in Experimental Example 1, and the same test as in Experimental Example 1 was performed. The shape of the through-hole was circular, the number of the through-holes was 1, the ratio between V1 and V2 was 0.5, and the ratio between X and R was 3.4. Although there was no buried through hole, deformation after the heat treatment was observed.

Comparative Example 2

A heat sink integrated stiffener was manufactured in the same manner as in Experimental Example 1, and the same test as in Experimental Example 1 was performed. The shape of the through-holes is circular, the number of through-holes is 9, the arrangement of the through-holes is shown in FIG. 11, the ratio between V1 and V2 is 0.5, and the ratio between X and R is 3.
And 2. Although there was no buried through-hole portion, deformation after the heat treatment was slightly observed.

(Comparative Example 3)

A heat sink integrated stiffener was manufactured in the same manner as in Experimental Example 1, and the same test as in Experimental Example 1 was performed. The shape of the through holes is circular, the number of the through holes is 9, and the arrangement of the holes is shown in FIG.
The ratio between V1 and V2 was 0.5, and the ratio between X and R was 0.2. The portion of the through-hole left unfilled was observed.

(Comparative Example 4)

A heat sink integrated stiffener was manufactured in the same manner as in Experimental Example 1, and the same test as in Experimental Example 1 was performed. The shape of the through holes is circular, the number of the through holes is 9, and the arrangement of the holes is shown in FIG.
The ratio between V1 and V2 was 1.1, and the ratio between X and R was 2.0. The portion of the through-hole left unfilled was observed.

Comparative Example 5

A heat sink integrated stiffener was manufactured in the same manner as in Experimental Example 1, and the same test as in Experimental Example 1 was performed. The shape of the through holes is circular, the number of the through holes is 9, and the arrangement of the holes is shown in FIG.
And the ratio between V1 and V2 is 0.05, and the ratio between X and R is 2.0.
And Although there was no buried through hole, deformation after the heat treatment was observed.

Comparative Example 6

0.7 mm thick, 27 mm wide, 27 m long
m heat-dissipating plate of oxygen-free copper is placed in a mold, and one surface thereof is pressed to form a recess having a length of 11 mm, a width of 11 mm, and a depth of 0.4 mm. ,
A heat sink integrated stiffener was manufactured, and the same test as in Experimental Example 1 was performed. Deformation after heat treatment was observed.

(Comparative Example 7)

0.7 mm thick, 27 mm wide, 27 m long
m into a mold, press one side of the mold, overhang from the other side to form a recess on the one side, cut the overhanging part on the other side, and finish To produce a heat sink integrated stiffener. Experimental Example 1
The same test was performed. Although no deformation was observed after the heat treatment, it took time to cut the overhang, and mass production in a short time was not possible.

(Comparative Example 8)

0.7 mm thick, 27 mm wide, 27 m long
m, a mask is formed on one surface of a heat-dissipating plate made of oxygen-free copper, a concave portion is formed, a cleaning process is performed, and a finishing process is performed to produce a heat-dissipating plate-integrated stiffener. Done. Although no deformation was observed after the heat treatment, the masking process required a long time, and short-term mass production was not possible.

Table 1 shows the above results.

[0055]

[Table 1]

[0056]

As described above, according to the heat sink integrated stiffener and the method of manufacturing the same according to the present invention, the manufacturing time of the heat sink integrated stiffener can be shortened, the manufacturing cost can be reduced, and mass production can be performed. .

Further, since no distortion remains, there is a great advantage that there is no deformation when heat is applied.

[Brief description of the drawings]

FIG. 1 is a plan view of a heat sink for a stiffener integrated with a heat sink according to the present invention.

FIG. 2 is a vertical sectional side view of a heat sink for a stiffener integrated with a heat sink according to the present invention.

FIG. 3 is a vertical sectional side view of the heat sink integrated stiffener of the present invention.

FIG. 4 is an enlarged vertical sectional side view of a part of the heat sink integrated stiffener of the present invention.

FIG. 5 is a plan view of a part of the heat sink integrated stiffener of the present invention.

FIG. 6 is a plan view showing another experimental example of the heat sink integrated stiffener of the present invention.

FIG. 7 is a plan view showing another experimental example of the heat sink integrated stiffener of the present invention.

FIG. 8 is a plan view showing still another experimental example of the heat sink integrated stiffener of the present invention.

FIG. 9 is a plan view showing still another experimental example of the heat sink integrated stiffener of the present invention.

FIG. 10 is a plan view showing still another experimental example of the heat sink integrated stiffener of the present invention.

FIG. 11 is a plan view showing a comparative example of the heat sink integrated stiffener of the present invention.

FIG. 12 is an exploded perspective view of a conventional semiconductor package.

FIG. 13 is a vertical sectional side view of a conventional semiconductor package.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat sink 1a One surface 1b The other surface 2 Concave part 3 Wiring board 3a Window hole 4 Terminal part 5 Chip 6 Terminal 7 Bonding wire 8 Sealant 9 Solder ball 10 Through hole

Claims (5)

[Claims] 1. A step of providing at least one through hole in a flat metal radiator plate, and pressing one surface of the radiator plate including the through hole to form a recess and move by the press. And filling the through hole with a metal part. 2. The volume of the through hole portion filled by the movement of the metal portion is 0.1 to 1.0 times, preferably 0.2 to 0.8 times the volume of the metal portion located in the recess. The method for manufacturing a stiffener integrated with a heat sink according to claim 1, wherein: 3. The distance between the edge of the recess and the edge of the through hole facing the edge is 0.4 to 3.3 times the distance between the center of the through hole and the edge of the through hole. 0 times, preferably 0.1 times.
3. The method according to claim 1, wherein the stiffener is integrated with a heat sink. 4. A flat heat radiating plate and a concave portion formed on one surface of the heat radiating plate, and the width and the length of the concave portion are 90% or less of the width and the length of the heat radiating plate, respectively. A stiffener integrated with a heat sink. 5. The stiffener integrated with a radiator plate according to claim 4, wherein the thickness of the radiator plate at the concave position is 10% or more of the thickness of the radiator plate.