JPH09148500A - Semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil sealing process for a semiconductor module which has a high safety and low cost. SOLUTION: An oil sealing process for a semiconductor module is provided with a step of horizontally placing a circuit board on which a thermal conductive member 19 is combined with a thermal conductive member 15 above a semiconductor device 3, steps of infusing oil 26 into an upper center of the thermal conductive member 19 and onto the circuit board in the atmosphere and vacuum clamping and a later step of a housing 7 pressing to the thermal conductive member 19 until the same position of assembled state. After that the housing module 7 is once elevated to the position where gas cant be induced into the module and is again pressed until the same position of assembled state. The circuit board and the housing 7 are tightly closed by bolts 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor module, and more particularly to a semiconductor module suitable for electronic devices having a high heat generation density such as large computers and supercomputers.

[0002]

2. Description of the Related Art A module having a structure in which a heat conductor having flexibility is provided between a semiconductor device and a housing and heat generated from the semiconductor device is transferred to the housing via the heat conductor to cool the module is, for example, an IBM module. Journal of Researc
h and Development Vol.35 No.3 (1991) describes an example of using oil as a heat transfer medium in a structure in which a metal piston is brought into contact with a semiconductor chip. In this conventional example, a cylindrical hole is provided in the housing at a position corresponding to each chip, a piston-shaped heat conductor is fitted in each hole, and the tip of this heat conductor contacts a semiconductor chip by a spring. The heat of the chip is transmitted to the housing. An oil port for introducing and discharging oil and gas is attached to the housing, and the valve is closed to seal the module.

[0003]

However, in the prior art, since a valve for enclosing oil in the module is attached, the number of parts increases and the cost increases, and at the same time oil and gas leak from the valve. There was a problem with safety.

It is an object of the present invention to provide an oil encapsulation process for semiconductor modules. That is, it is to provide an oil encapsulation process for a semiconductor module with high safety and low cost.

[0005]

In order to achieve the above object, the present invention provides a circuit board, a plurality of semiconductor devices mounted on the circuit board, a housing covering the circuit board, and the semiconductor device. Extending in a direction perpendicular to the semiconductor device surface, which is provided between the housing and
And an oil encapsulation process of a semiconductor module comprising a heat conductor composed of first and second heat conducting members having heat transfer surfaces facing each other with a gap therebetween, The circuit board mounted by combining the second heat conducting member with the heat conducting member is horizontally placed, and the center of the upper portion of the second heat conducting member, and
Oil is injected onto the circuit board in the atmosphere. Next, the module is placed in the chamber, a vacuum is drawn, and then the housing is pressed against the second heat conducting member to the same position as in the assembled state. After that, the housing is temporarily lifted up to a position where gas can be introduced into the module, nitrogen gas is introduced, and the circuit board and the housing are sealed with bolts by pressing again to the same position where the housing is assembled. To do.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

An embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a vertical cross-sectional view showing a semiconductor module according to the present embodiment after oil filling. As shown in FIG. 1, a plurality of semiconductor devices 3 are mounted on a ceramic multilayer wiring board 2 having a large number of I / O pins 1 via minute solder balls 4. A flange 5 is attached to the substrate 2, and the flange 5 and the housing 7 are fixed by bolts 8 with an O-ring 6 interposed therebetween to hermetically seal a space 9 surrounded by the flange 5 and the substrate 2. There is.

A space 9 surrounded by the housing 7 and the substrate 2 is filled with a liquid such as electrically insulating oil 26. A plurality of flow paths 10 for passing a cooling fluid are integrally formed with the housing 7 on the upper end surface of the housing 7,
An upper lid 11 is attached so as to cover the flow path 10.
Further, the housing 7 or the upper lid 11 is provided with a coupler 12 having a built-in valve mechanism.
The cooling fluid flows in and out from the outside via the.

The semiconductor device 3 has a base 13 and a first heat conducting member 15 having a plate-shaped first fin 14 formed integrally with the base 13 and perpendicular to the base 13.
Are fixed by the solder layer 16. It is desirable that the material of the first heat conducting member 15 has electrical insulation, high thermal conductivity, and a linear expansion coefficient close to that of the semiconductor device material. Aluminum nitride (AlN) is an example of such a material. Further, the second heat conducting member 19 including the base 17 and the flat plate-shaped second fins 18 is
The first heat conducting member 15 is engaged with the first heat conducting member 15 through a minute gap and forms a pair with the first heat conducting member 15 to form one heat conductor. The base portion 17 of the second heat conduction member 19 is
Each semiconductor device 3 has an area substantially equal to the area occupied on the substrate 2, and is formed to be larger than the area of the semiconductor device 3. Second heat conducting member 1
The base portion 17 of 9 is pressed against the flat inner wall 20 of the housing by the elastic member 28 provided between the first heat conducting member 15 and the second heat conducting member 19. Contact surface 2 between inner wall of housing 7 and base portion of second heat conducting member 19
3 acts as a heat transfer surface and absorbs the deformation of the module in the surface direction.

FIG. 2 shows an oil filling process according to an embodiment of the present invention. First, the elastic member 28 is inserted into the first heat conduction member 15 above the semiconductor device 3 and the multilayer wiring board 2 mounted by combining the second heat conduction member 19 is placed horizontally, and the second heat conduction member 2 is placed. A prescribed amount of oil 26 is injected into the center of the upper surface of the base 17 of the member 19 and on the multilayer wiring board 2 using the dispenser 29 in the atmosphere (FIG. 2A). The amount of the oil 26 enclosed is such that a space 22 is provided to alleviate an increase in the internal pressure of the module due to thermal expansion of the oil 26 in a state where the module is assembled and is set upright.
The height of the oil level 21 in the module between the lower end and the upper end of the first fin 14 fixed to the uppermost semiconductor device 3, preferably the height from the center between the lower end and the upper end of the first fin 14 to the upper end. It is controlled so that it comes to a height between the heights (Fig. 1).

Next, the module is placed in the chamber (not shown).
And then vacuuming 31 (FIG. 2 (b)), and then using the jig 27 to move it to the same position as when the housing 7 was assembled.
It is pressed against the heat conduction member 19 (FIG. 2 (c)). At this time,
The oil 26 applied to the upper surface of the base 17 is spread by the inner wall 20 of the housing 7 and filled in the minute gap of the contact surface 23. At the same time, the oil 26 injected onto the multilayer wiring board 2 is filled in the gap between the first fin 14 and the second fin 18. After that, the housing 7 is once lifted up to a position where gas can be introduced into the module, and an inert gas 30 such as nitrogen is introduced up to a specified pressure (see FIG. 2).
(d)) At this time, the oil 26 is held by the surface tension in the minute gap between the base 17 and the inner wall 20 and the gap between the first fin 14 and the second fin 18. Next, the housing 7 is pressed again to the same position as in the assembled state (FIG. 2 (e)), and the multilayer wiring board 2 and the housing 7 are sealed with bolts 8 (FIG. 2 (f)). Thus, the oil 26 is enclosed in the module.

In this embodiment, since there is no valve for introducing oil or gas, there is little possibility of oil or gas leaking from the module.

[0013]

According to the present invention, since there is no valve for introducing oil or gas, there is little possibility of oil or gas leaking from the module, so that the safety is improved and the cost of parts is reduced.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of a module after enclosing oil according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing an oil sealing process according to the embodiment of the present invention.

[Explanation of symbols]

1 ... I / O pin, 2 ... Multilayer wiring board, 3 ... Semiconductor device, 4 ... Solder ball, 5 ... Flange, 6 ... O ring, 7
... Housing, 8 ... Bolts, 9 ... Sealed space, 10 ... Flow path, 11 ... Upper lid, 12 ... Coupler, 13, 17 ... Base,
14, 18 ... Fins, 15, 19 ... Heat conduction member, 16 ...
Solder layer, 20 ... Flat inner wall, 23 ... Contact surface, 26 ... Oil, 27 ... Jig, 28 ... Elastic member, 29 ... Dispenser.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takahiro Oguro 1 Horiyamashita, Hadano-shi, Kanagawa Hitachi, Ltd. General-purpose computer division (72) Inventor Mitsunori Tamura 1-horiyamashita, Hadano, Kanagawa Hitachi General Co., Ltd. Computer Division (72) Inventor Ryuichi Kurisu 1st Horiyamashita, Hadano City, Kanagawa Prefecture, Hitachi General Computer Division

Claims (1)

[Claims] 1. A circuit board, a plurality of semiconductor devices mounted on the circuit board, a housing covering the circuit board, and a semiconductor device surface provided between the semiconductor device and the housing. Extending in the vertical direction,
And a heat conductor composed of first and second heat conducting members having heat transfer surfaces opposed to each other with a gap therebetween, in the first heat conducting member above the semiconductor device. The circuit board mounted by combining the second heat conducting member is placed horizontally, and a prescribed amount of oil is placed on the center of the upper portion of the second heat conducting member and on the circuit board in the atmosphere or vacuum. Is injected, the semiconductor module is placed in a chamber and a vacuum is drawn, and then the second heat conducting member is pressed to the same position as that where the housing is assembled, and then gas can be introduced into the semiconductor module. Once the housing is lifted to a position, an inert gas is introduced, and the housing is pressed again to the same position as when the housing is assembled. Semiconductor module, characterized in that a sealed grayed with bolts.