JPH0653374A - Electronic circuit device - Google Patents

Abstract

PURPOSE:To prevent the stress from being applied to an electronic circuit part even if there is the presence of warpage of a substrate, by providing a through hole in a plate member and a filling member for directly connecting the plate member and the electronic circuit part by filling the through hole. CONSTITUTION:An electronic circuit apparatus comprises a cooling jacket 4 for cooling a semiconductor chip 2, and a plate member 3, a filling member 5 and a heat transfer board 6 for thermally connecting the semiconductor chip 2 to the cooling jacket 4. The plate member 3, the filling member 5 and heat transfer board 6 are in contact with the cooling jacket 4 through a thermal conductive grease 11, and also are in contact with the semiconductor chip 2. In this case, the plate member 3 has a through hole extending from the side of the semiconductor chip 2 to the side of the cooling jacket 4, and the through hole is installed on a mounting place of the semiconductor chip 2. Thus, an electronic circuit part can be replaced easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for mounting a highly integrated semiconductor chip by high density fine connection.

[0002]

2. Description of the Related Art In order to increase the speed of an electronic computer, it is necessary to shorten the wiring length of a semiconductor integrated circuit used for calculation and storage. Therefore, high integration of semiconductor integrated circuits is progressing. Along with the high integration of this semiconductor integrated circuit, the number of input / output terminals from the semiconductor integrated circuit to the wiring board is increasing, and the connecting portion thereof is becoming finer. As a result, the strength of the connection portion is reduced, and the service life is shortened.

On the other hand, there has been proposed a technique for cooling the semiconductor chip to reduce stress / strain applied to the connecting portion between the chip and the wiring board and other connecting portions and to improve the reliability of the connecting portion. There is. For example, Japanese Patent Laid-Open No.
According to Japanese Patent Publication No. 7456, as shown in FIG. 7, cooling water is circulated inside the bellows 15 having a bellows structure,
A structure is disclosed in which the semiconductor chip 2 is cooled by bringing it into contact with the semiconductor chip 2. Further, for example, in Japanese Unexamined Patent Publication No. 1-125962, a structure for cooling the semiconductor chip 2 by bringing cooling water into contact with the diaphragm 16 having a structure for absorbing stress as shown in FIG. Japanese Unexamined Patent Publication No. 3-283451 discloses a structure in which the semiconductor chip 2 is brought into contact with a cooling member via solder to cool it, as shown in FIG.

Further, due to the high integration of electronic circuits, the heat generation density in the integrated circuits is increased, and the structure is deformed by the internal temperature change of the circuit during the mounting process and the actual operation, or the thermal expansion from the three-dimensional temperature distribution. Is becoming a serious problem. Further, improvement of cooling performance is also an important issue in order to cope with internal temperature change, uniform temperature distribution, and increase in heat generation density.

Therefore, from the conventional type shown in FIG. 10 in which the heat dissipation area is increased by the comb teeth 19 and forced air cooling is used, to the type in which cooling is performed by contact with the water cooling system and the comb teeth 20 as shown in FIG. 11 and Freon. In order to improve the cooling performance, it is changed to a liquid immersion type in which the chip is directly dipped and cooled, or an indirect water cooling type in which the chip is fixed to the module cap with brazing material or solder and cooled close to the water cooling jacket Technology development is being carried out. For these techniques, see Japanese Patent Application Laid-Open No. 2-83.
957.

[0006]

However, in the above-mentioned prior art, it is said that both sufficient heat dissipation characteristics and good workability and assemblability of the semiconductor module structure including the cooling system are not compatible with each other. There was a problem.

Further, in any of the semiconductor module structures described in the prior art, if the structure is thermally deformed during the mounting process, connection failure may occur.
In addition, repeated turning on and off during actual operation may cause destruction of the connection part due to a cycle of transient temperature distribution. These are considered to be problems caused by the structure of the conventional structure. Since such a problem lowers the reliability of the connection of the semiconductor module, it is desired to develop a structure for improving them.

The problems of the prior art will be specifically described. Although the bellows and diaphragm structure described above have good cooling properties,
When replacing a defective chip, the water cooling system must be removed, and the repairability is poor. Since the water-cooled system has a large number of parts, the number of parts that must be removed when replacing a defective chip is large, and variations in processing accuracy and assembly accuracy greatly affect the service life of the connection part. In addition, the bellows or diaphragm structure must have a spring structure to prevent stress on the chip. Therefore, a space for the spring structure is required, and there is a limit to downsizing the entire module structure.

Next, the comb-tooth heat conduction structure has an advantage that it is possible to allow a shift of the comb teeth within the meshing allowance range. Therefore, the comb-shaped heat conduction structure has better workability, assembling property, and repairability than other structures. Since the contact thermal resistance of the tooth structure is large, there is a limit to the reduction of the thermal resistance. Therefore, the cooling performance cannot be improved against the increase in heat generation density of the chip. There is also a problem that the module height is increased to secure the comb tooth space.

In addition, the solder fixing structure has advantages that the structure is simple and the repairability is good, the cooling performance can be greatly improved because the chip can be brought close to the cooling system, and the module can be greatly downsized. There are many, but it is difficult to deal with the warp of the substrate. That is, most of the substrates have a warp, but when the substrate is warped, the chip also tilts. In that case, the distance between the chip and the cooling system varies depending on the warp of the substrate. Therefore, the amount of solder to be filled between the chip and the cooling system varies depending on the part of the board. If such variations are dealt with individually, the manufacturing efficiency will be extremely reduced. But,
In the solder fixing structure, since the solder absorbs the stress at the joint between the chip and the cooling system, unless the amount of solder is adjusted, the stress applied to the chip at the joint between the chip and the solder becomes large.

An object of the present invention is to easily replace electronic circuit parts, to have a small size and to provide high cooling performance.
Another object of the present invention is to provide an electronic circuit device that does not apply stress to electronic circuit parts even when the substrate is warped, and a high-performance electronic computer equipped with the electronic circuit device as an arithmetic / memory element.

[0012]

In order to solve the above problems, according to the present invention, a substrate, an electronic circuit component, a connecting means for electrically connecting the substrate and the electronic circuit component, and the electronic circuit An electronic circuit device comprising: a cooling unit that cools a component; and a connecting unit that contacts both the cooling unit and the electronic circuit component to thermally couple the cooling unit and the electronic circuit component. The connecting means has a plate-shaped member having a through hole and a filling member for filling the through hole, and the plate-shaped member has an opening of the through hole that contacts the electronic circuit component. And at least a part of the filling member that contacts the electronic circuit component and that closes the opening of the through hole on the electronic circuit component side. An electronic circuit device is provided.

[0013]

In the present invention, the electronic circuit component is arranged on the substrate and is electrically connected to the substrate by the connecting means. The connecting means conducts the heat of the electronic circuit component to the cooling means by contacting both the electronic circuit component and the cooling means to cool the electronic circuit component.

The connecting means includes a plate member having a through hole,
And a filling member that fills the through hole. The plate-shaped member is provided with an opening of the through hole on the side that contacts the electronic circuit component and on the side that contacts the cooling means. The filling member is
At least a part thereof contacts the electronic circuit component and closes the opening of the through hole on the electronic circuit component side.

When the board has a warp, the positional relationship between the plate-shaped member and the electronic circuit component is adjusted by adjusting the warp of the board.
However, in the present invention, it is possible to allow the variation with the same amount of the filling member. That is, due to the warp of the substrate, the plate member and the electronic circuit component are
When they are separated from each other, the gap between the plate-shaped member and the electronic circuit component is large, and the filling member fills the gap, so that the amount of the filling member filling the inside of the through hole is small. Further, when the plate member and the electronic circuit component are close to each other, the gap between the plate member and the electronic circuit component is small, and the amount of the filling member filling the inside of the through hole is large. In either case, the filling member closes the opening of the through hole on the electronic circuit component side. This is a technology made possible because the plate-shaped member has a through hole that penetrates from the electronic component side to the cooling means side.

Further, since the electronic circuit device of the present invention has a simple structure, the electronic circuit parts can be easily replaced. Further, since the electronic circuit component is directly connected to the cooling means by the filling member and the plate member, the cooling efficiency is high.

As described above, in the electronic circuit device of the present invention, by using the through hole in the plate member and the filling member for directly connecting the plate member and the electronic circuit component by filling the through hole, Provided is an electronic circuit device that does not apply stress to an electronic circuit component even when the substrate is warped.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electronic circuit device according to an embodiment of the present invention will be described below with reference to FIGS.

First, the mounting structure of the electronic circuit device according to the first embodiment of the present invention will be described with reference to FIG. The electronic circuit device of the present embodiment is an insulating multilayer substrate 1 having signal pins 9 on its back surface.
And a plurality of (only one is shown in FIG. 1) semiconductor chips 2 on the insulating multilayer substrate 1. The semiconductor chip 2 and the insulating multilayer substrate 1 are connected by solder bumps 8. The electronic circuit device further includes a cooling jacket 4 for cooling the semiconductor chip, a top plate 3, a filling member 5, and a heat transfer plate 6 for thermally connecting the semiconductor chip 2 to the cooling jacket 4. ing. The top plate 3, the filling member 5, and the heat transfer plate 6 are in contact with the cooling jacket 4 via the heat conductive grease 11. The top plate 3, the filling member 5, and the heat transfer plate 6 are also in contact with the semiconductor chip 2. Top plate 3
Are supported by the frame 7 arranged at the end of the substrate 8. The substrate 1 and the frame 7, and the frame 7 and the top plate 10 are connected by the brazing material 10.
The cooling jacket 4 has a cooling pipe 4a for circulating cooling water inside.

The top plate 3 is made of ceramic.
The top plate 3 has a through hole penetrating from the semiconductor chip 2 side to the cooling jacket 4 side. The through hole is provided at the mounting position of the semiconductor chip 2. The size of the opening of the through hole on the semiconductor chip 2 side is slightly smaller than the size of the semiconductor chip 2. The top plate 3 is arranged so that the upper surface of the semiconductor chip 2 and the lower surface of the top plate 3 are substantially in the same plane.

In this through hole, a filling member 5 made of a metal having a low melting point (for example, In48Sn (melting point: about 120 ° C.), Bi56.3Pb) is used.
(Melting point: about 125 ° C)) is filled. The melting point of the material forming the filling member 5 is lower than the melting point of the solder forming the solder bump 8. A heat transfer plate 6 made of a highly heat conductive metal such as Cu is placed in the opening on the cooling jacket 4 side. At least a part of the filling member 5 contacts the electronic circuit component, and closes the opening of the through hole on the electronic circuit component side.

Further, the heat transfer path is expanded by expanding the through hole on the cooling jacket 4 side to provide a step. The heat transfer metal thin plate 6 is also provided with a step corresponding to the shape of the projecting portion 3a of the step on the top plate side. This overhanging portion 3a is
It also has a role as a reinforcing material that enhances the rigidity of the top plate 3. Further, when the processing accuracy and the assembly accuracy of the insulating substrate 1 and the top plate 3 are poor, this overhanging portion supports the heat transfer plate 6 when the cooling jacket 4 is tightened, so that excessive pressure is applied to the solder bumps 8. It also serves as a spacer to prevent addition.

In this embodiment, the lower surface of the heat transfer plate 6 has a curvature as shown in FIG. When the filling member 5 has such a curvature, the filling member 5 spreads out from the center side of the heat transfer plate 6, so that a void is not easily formed on the connection surface. Further, since the thickness of the filling member becomes thinner toward the center of the chip, there is an advantage that the structure has a small thermal resistance and the temperature distribution of the entire module is made uniform.

A procedure for assembling the electronic circuit device of this embodiment will be described. First, the semiconductor chip 2 is connected to the substrate 1 by the solder bumps 8. Next, on the substrate 1,
The frame 7 is attached by the brazing material 10. Then, the top plate 3 is mounted on the frame 7. At this time, the lower surface of the top plate 3 and the upper surface of the semiconductor chip 2 are aligned with each other, and the top plate 3 is arranged such that the semiconductor chip 2 has a height such that no pressure is applied thereto.

From the through hole of the top plate 3 onto the semiconductor chip 2,
A low melting point metal block for forming the filling member 5 is placed.
Next, the low melting point metal is heated and melted to completely fill the opening between the semiconductor chip 2 and the top plate 3 and the through hole on the semiconductor chip 2 side. Further, the heat transfer plate 6 is put in the opening of the through hole on the cooling jacket side in a state where the low melting point metal is melted. At this time, the heat transfer plate 6 and the melted low melting point metal are brought into contact with each other. When the low melting point metal overflows from the upper surface of the top plate 3, it is sucked and removed. Next, the low melting point metal is cooled and solidified to form the filling member 5. Apply heat conductive grease 11 on the top plate 3 and the heat transfer plate 6,
Complete with a water cooling jacket.

Next, a procedure for replacing the semiconductor chip 2 at the time of repairing the electronic circuit device of this embodiment will be described. First, the water cooling jacket 4 is removed. Then, the filling member 5 is heated to melt the low melting point metal forming the filling member 5. In this state, the heat transfer plate 6 is removed, and the molten low melting point metal is sucked. Next, remove the top plate 3,
Replace the semiconductor chip.

As described above, in the electronic circuit device of this embodiment, the semiconductor chip 2 is in contact with the cooling jacket 4 through the heat conductive grease 11, the heat transfer plate 6 and the filling member 5. Thermally conductive grease 11, heat transfer plate 6, and filling member 5
Has good thermal conductivity, so that the semiconductor chip 2 can be effectively cooled. Further, even when the substrate has a warp, the filling member 5 can fill the gap between the semiconductor chip 2 and the top plate 3 to allow the warp of the substrate without applying stress to the semiconductor chip 2. .

Furthermore, as described above, the electronic circuit device of this embodiment has a small number of parts, so that the semiconductor chip 2 can be easily replaced during repair.

Further, since the step is provided inside the through hole, there is an advantage that the contact area between the top plate 3 and the filling member 5 is large and the joining strength between the top plate and the filling member is large.

The semiconductor chip 2 is made of a low melting point metal.
Since the top plate 3 is connected to the top plate 3, the temperature difference from the melting point to room temperature is small, and the deformation of the structural member due to the thermal expansion / contraction of the structural member during the heating / cooling process at the time of connection is small. Almost no extra stress or strain is applied to the.

A second embodiment of the present invention will be described with reference to FIG.

The present embodiment is an example in which the size of the opening of the through hole in the embodiment of FIG. 1 is approximately equal to or slightly larger than the size of the semiconductor chip 2. In this case, even if the insulating multilayer wiring board 1 and the top plate or the cap 3 are warped so that the upper surface of the semiconductor chip 2 is located above the lower surface of the top plate 3, the semiconductor chip 2 is placed in the through hole. By entering, the upper surface of the semiconductor chip 2 does not contact the top plate. Therefore, the upper surface of the semiconductor chip 2 and the top plate 3 can be connected without applying extra pressure to the solder bumps 8.

A third embodiment of the present invention will be described with reference to FIG.

This embodiment is an embodiment in which no step is provided in the through hole. Similar to the second embodiment, the size of the opening of the through hole is substantially equal to the size of the semiconductor chip 2, or
I made it a little larger. Since there is no step in the through hole,
The top plate 3 can be easily processed and can flexibly deal with the warp of the insulated wiring board 1 as in the embodiment of FIG.

Further, in this embodiment, when the semiconductor chip 2 is replaced at the time of repair, the filling member 5 and the heat transfer plate 6 are used.
It is also possible to replace the semiconductor chip 2 through the through hole without removing the top plate 3 after removing and. In this case, the number of man-hours for replacement can be reduced, so that the efficiency of repair can be increased.

A fourth embodiment of the present invention will be described with reference to FIG.

In this embodiment, the size of the opening on the side of the semiconductor chip 2 of the through hole of the top plate 3 is made equal to or larger than that of the semiconductor chip 2, and the size of the opening on the side of the cooling jacket 4 is reduced to make a step. Is provided. Although the cooling path is narrowed by this step, there is an advantage that the rigidity of the top plate 3 is increased.

A fifth embodiment of the present invention will be described with reference to FIG.

In the embodiment shown in FIG. 5, the top plate 3 is different in the members constituting the outer peripheral portion and the inner portion. The outer peripheral portion was a thick plate frame, and the inside was composed of a work piece 12 of an intermediate metal thin plate.
The processed product 12 of the intermediate thin metal plate has a through hole in which the semiconductor chip 2 is mounted. With this configuration, it is possible to reduce the rigidity of the mounting portion of the semiconductor chip 2 while keeping the rigidity of the top plate 3 as a whole high, and to reduce the stress on the solder bumps.

A sixth embodiment of the present invention will be described with reference to FIG.

In the electronic circuit device 3 of this embodiment, O-rings 14a and 14b are arranged between the top plate 3 and the frame 7 and between the frame 7 and the insulating multilayer wiring board 1, respectively. Also, between the top plate 3 and the semiconductor chip 2,
An O-ring 14c is arranged. O-rings 14a, 14
b and 14c are airtightly sealed and prevent the filling member 5 from leaking. An exhaust pipe 13 is arranged in the frame 7.

In this case, before filling the filling member 5, the gas inside the airtight space formed by the top plate 3 and the substrate 1 is exhausted from the exhaust pipe 13 in a high temperature atmosphere. If the processing accuracy of the inner surface of the member forming this space is poor, that is, if the processing accuracy of the top plate 3 is poor, or the undulations of the multilayer substrate 1 are severe, the exhaust is not sufficiently performed. It is possible to detect accuracy at the same time. Further, there is an advantage that a substantially constant load can be applied to all the solder bumps 8. Further, after the sealing, an inert gas is injected from the exhaust pipe 13 and sealed, so that the structure can be hermetically sealed.

In the above-described first to sixth embodiments, the top plate 3 and the portion of the frame 7 supporting the top plate 3 may be formed as a cap-shaped member having an integral structure.
Further, the semiconductor chip 2 can be configured in any way even when it is replaced with a chip carrier or other electronic circuit parts.

The effects of the above-described six embodiments can be summarized as the following six points.

(1) The semiconductor chip 2 and the top plate 3 are structurally separated from each other during the mounting process, and stress generated at each joint is
The strain can be reduced.

(2) The low melting point metal forming the filling member 5 has low rigidity at the same time, which absorbs the internal temperature change and the deformation due to the temperature distribution during actual operation, and the stress and strain generated in other joints. Can be reduced.

(3) The top plate 3 can be connected to the cooling jacket 4 via the heat conductive grease 11, and the heat radiation path can be specified. Further, since the semiconductor chip 2 can be brought closer to the cooling system, the thermal resistance is reduced and the cooling performance can be improved, so that the temperature distribution and temperature rise in the electronic circuit device are reduced and the thermal deformation of the entire electronic circuit device is reduced.

(4) In a state in which the low melting point metal forming the filling member 5 in the through hole is melted, the upper surface of the top plate 3 and the upper surface of the heat transfer plate 6 are simultaneously pressed by a flat plate and cooled to cool the multilayer substrate 1 It is possible to absorb the warp and flatten the upper surface of the electronic circuit device.

(5) When the surface of the heat transfer plate 6 on the semiconductor chip 2 side has a convex shape with a curvature, the low melting point metal forming the filling member wets and spreads from the center, resulting in a connection defect such as a void. Can be significantly reduced.

(6) Due to the curvature of the heat transfer plate 6, the heat resistance of the filling member 5 is minimized at the center of the chip 2, and the temperature distribution generated on the chip 2 due to heat generation of the chip 2 is reduced. Therefore, the thermal stress / strain generated in the solder bumps 8 due to the thermal deformation of the chip 2 is reduced.

(7) When the defective chip 2 is replaced, the low melting point metal forming the filling member 5 is first melted and absorbed, and the chip 2 and the top plate 3 are completely separated and then repaired. it can.

In this embodiment, the heat transfer plate 6 has a curvature. However, it is not always necessary to have a curvature, and a simple flat plate or a stepped flat plate can be selected if a shape suitable for the required performance is selected. good.

[0053]

As described above, according to the present invention, although the electronic circuit parts can be easily replaced, the electronic circuit device is small in size and has high cooling performance.
It is possible to provide an electronic circuit device that does not apply stress to electronic circuit components even when the substrate is warped.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of an electronic circuit device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of an electronic circuit device according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing the structure of an electronic circuit device according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing the structure of an electronic circuit device according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view showing the structure of an electronic circuit device according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view showing the structure of an electronic circuit device according to a sixth embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a structure of an electronic circuit device using a bellows structure in a cooling unit according to a conventional technique.

FIG. 8 is a cross-sectional view showing a structure of an electronic circuit device using a diaphragm on the upper surface of a module according to a conventional technique.

FIG. 9 is a cross-sectional view showing the structure of an electronic circuit device in which a module top surface and an LSI back surface are fixed to each other with solder by a conventional technique.

FIG. 10 is a cross-sectional view showing a structure of an electronic circuit device using a comb tooth according to a conventional technique.

FIG. 11 is a cross-sectional view showing a structure of an electronic circuit device using a comb tooth according to a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Insulating multilayer wiring board, 2 ... Chip, 3 ... Top plate, 4 ... Cooling jacket, 5 ... Low melting point metal, 6 ... Heat transfer plate, 7 ... Module frame, 8 ... Solder bump, 9 ... I / O pin,
10 ... Brazing material for sealing, 11 ... Thermally conductive grease, 12 ... Intermediate thin metal plate, 13 ... Exhaust pipe, 14 ... O ring, 15 ... Bellows, 16 ... Diaphragm, 17 ... Solder for fixing chip back surface, 18 ... Support Ring, 19 ... Radiating fin, 20 ...
Comb teeth.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahide Harada, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd., Production Engineering Laboratory, Hitachi, Ltd. Hiritsu Manufacturing Kanagawa Factory (72) Inventor Mitsugu Shirai 1 Horiyamashita, Hadano City, Kanagawa Prefecture Hitate Manufacturing Kanagawa Factory

Claims (9)

[Claims] 1. A substrate, an electronic circuit component arranged on the substrate, connecting means for electrically connecting the substrate and the electronic circuit component, and cooling means for cooling the electronic circuit component.
In contact with both the cooling means and the electronic circuit component,
It is an electronic circuit device which has a connecting means which thermally connects the cooling means and the electronic circuit component, wherein the connecting means includes a plate-shaped member having a through hole, and a filling member for filling the through hole. The plate-shaped member has an opening of the through hole on the electronic circuit component side and the cooling means side, the filling member, at least a portion is in contact with the electronic circuit component, Further, the electronic circuit device is characterized in that the opening of the through hole on the electronic circuit component side is closed. 2. The electronic circuit device according to claim 1, wherein the filling member is made of a material having a melting point lower than a melting point of a material forming the connecting means. 3. The connecting means according to claim 1, further comprising a heat transfer plate that contacts the cooling means and the filling member to conduct heat, and the heat transfer plate cools the inside of the through hole. An electronic circuit device, wherein the electronic circuit device is arranged in an opening portion on the means side. 4. The electronic circuit device according to claim 3, wherein the heat transfer plate has a central portion thicker than a peripheral portion. 5. The connecting means according to claim 1, further comprising a supporting member for supporting the plate-shaped member on the substrate in a state of not being in contact with the electronic circuit component. Electronic circuit device. 6. The opening of the through hole of the plate-shaped member is larger than the electronic component according to claim 5, and in the support member, a part of the electronic component enters into the through hole. An electronic circuit device, wherein the plate-shaped member is supported at a height. 7. The electronic circuit device according to claim 6, wherein the through hole has a step portion on an inner wall thereof. 8. The electronic circuit component according to claim 1, wherein:
An electronic circuit device, which is a semiconductor chip or a chip carrier. 9. The electronic circuit device according to claim 2, wherein the filling member is solder.