JPH04188861A - Electronic circuit package - Google Patents

Abstract

PURPOSE:To enable I/O terminals to be enhanced in number by a method wherein a heat sink where a heat pipe is built is brought into thermal contact with a region where I/O terminals and/or power feed terminals are not mounted. CONSTITUTION:I/O terminals 3 are divided into groups, where each group is composed of a certain number of terminals 3, and the terminals 3 are dispersedly mounted on the side of a multi-chip wiring board 2 opposite to its other side where LSI chips 1 are mounted. A thin heat sink 9 in which a heat pipe is built is brought into thermal contact with a region where the terminal groups are not mounted, and heat released from the chips 1 is conducted to the heat sink 9 through the intermediary of the wiring board 2 and dissipated outside. By this constitution, the I/O terminals 3 can be led out two-dimensionally from the wiring board 2 mounted with a large number of the chips 1, so that an electronic circuit package can be sharply increased in total number of I/O terminals and enhanced in cooling capacity by the heat sink 9 of high thermal conductivity notwithstanding its thermal contact surface small in area.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to electronic circuit packages that require a large number of I/O terminals and high cooling capacity due to faster systems and higher density packaging. be.

[Prior Art] Figure 0 shows a conventional electronic circuit package structure, in which 1 is an LSI chip, 2 is a multi-chip wiring board, and 3 is an electrical connection with an upper mounting layer (upper mounting level). ■/○ pin to remove, 4 is a sealing cap to protect LSI chip 1, 5 is an air-cooled heat sink, 6 is I/O
A connector 7 is used to fit the bin 3 and electrically connect the multi-chip wiring board 2 and the upper mounting layer, and 7 indicates a motherboard which is the upper mounting layer. Also the 11th
The figure is a top view of Figure /O with the sealing cap 4 removed, and 8 is a sealing cap ring (for sealing with the sealing cap 4 by laser explosion welding, etc.). (a metal thin film ring provided on a multi-chip wiring board 2).

This structure is a structure in which an LSI chip 1 is mounted face-up on a multi-chip wiring board 2.
The heat generated is guided to the outside air via the multi-chip wiring board 2 by an air-cooled heat tank 5 bonded to the back surface of the multi-chip wiring board 2. Generally, the heat transfer coefficient during air cooling is about two orders of magnitude lower than that during liquid cooling, so in order to achieve sufficient heat radiation and dissipation, it is necessary to make the heat transfer area of the heat tank 5 as large as possible. Therefore, it was necessary to reserve the back surface of the conventional multi-chip wiring board 5 for heat radiation.

[Problems to be Solved by the Invention] However, in the conventional electronic circuit package structure described above, since the back surface of the multi-chip wiring board 2 is used for thermal connection with the heat link 5, the I/O
There is a problem in that the area from which the pins 3 can be extracted is limited only to the surface on which the LSI chip 1 is mounted and around the multi-chip wiring board 2. On the other hand, I/O pins 3 for electrically connecting the multichip wiring board 2 and the upper mounting layer (here, the motherboard 7) are connected to the LSI chip mounted on the multichip wiring board 2. As the total number of gates in 7P1 increases, it tends to increase more and more. The mounting pitch of I/O pins 3 when performing bin-type 1/O as in the conventional package structure is approximately 1.27 ffim due to its manufacturing limit, and therefore the required I/O
If the /O number is about 500, the increase in the external dimensions of the multi-chip wiring board 2 is slight, or ■ /O number /O00~2
000 order, an increase in external dimensions is unavoidable.

Therefore, in the conventional example, multichi, from I/○ bin 3.

This method has the drawback that the distance to the wiring on the printed wiring board 2 is extended, and is not suitable for applications such as computers where reduction of delay due to wiring is the most important issue. Furthermore, since the wiring is spread out in the peripheral area, there is also the drawback that the total number of wiring increases.

Additionally, a structure has been proposed in which the multi-chip wiring board 2 and the motherboard 7, which is the upper mounting layer, are connected by using a flexible/pull printed board with a narrow terminal pitch. Since only the periphery is in the ■/○ region, there is no solution other than narrowing the terminal pitch in order to cope with the increase in the number of I/Os. In addition, when mounting the multichip wiring board 2 on the motherboard 7, alignment becomes increasingly difficult, and the connection terminals on the flexible printed board and the connection terminals with the multichip wiring board 2 are also becoming smaller. When replacing the wiring board 2, deformation and friction occur, which limits the number of replacements.

Therefore, even in a structure using a flexible printed board with a narrow terminal pitch, there is a limit to the number of I/Os that can be extracted from the flexible printed board.

Although the above description is based on the assumption that the multichip wiring board 7 is air-cooled, a structure using liquid cooling is also conceivable. However, even in this case, since the LSI chip 1 is mounted face-up, in order to obtain high cooling capacity,
It is common to have a structure in which a liquid-cooled heat sink is thermally connected in place of the air-cooled heat sink at the same position, so even if the cooling capacity is high, the above problem cannot be solved.

As explained above, the problems with the conventional structure are as follows:
Considering the heat dissipation from the SI circuit board 1, there is a limit to the I/O terminals from the multi-chip wiring board 2.
This can be summed up as not being able to meet the demand for an increase in the number of O terminals.

The present invention was devised to solve the above-mentioned problems, and its purpose is to
○An object of the present invention is to provide an electronic circuit package that allows the number of terminals to be extracted easily and has a high cooling capacity that does not limit heat dissipation from the LSI chip 1.

[Means for Solving the Problems] The configuration of the electronic circuit package of the present invention for achieving the above object includes at least one bare chip or at least one bare chip.
In an electronic circuit package having a structure in which chips mounted in more than one case are mounted on a wiring board, and a plurality of I/O terminals and/or power supply terminals are provided on the wiring board to electrically connect the chips to an upper mounting level, Some of the I/O terminals and/or power supply terminals are grouped, at least one or more of the groups are distributed and mounted on the wiring board, and a heat vibrator is built in an area of the wiring board where the group of terminals is not mounted. It is characterized by bringing a cooled heat sink or a liquid-cooled heat sink into thermal contact.

[Function] The present invention uses a heat sink with a built-in heat vibrator or a liquid-cooled heat sink as a means to dissipate the heat of a chip mounted on a wiring board, and its high thermal conductivity makes it possible to replace conventional metal materials. The I
The number of I/O terminals can be increased, and the I/O terminals can be mounted in a distributed manner to reduce the wiring distance.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a perspective view showing a first embodiment of the present invention. Further, FIG. 2 is a cross-sectional view of FIG. 1, and shows a state in which the multi-chip wiring board and the motherboard are separated. Further, FIG. 3 shows a top view of FIG. 1, and FIG. 4 shows a back side of the multi-chip wiring board shown in FIG. 1.

In each figure, l is an LSX chip, 2 is a multi-chip wiring board, 3 is an I/O terminal, 4 is a sealing cap, 7 is a motherboard, 8 is a sealing cap ring, and 9 is a thin type with a built-in heat vibrator. A heat sink /O is an air-cooled heat sink, 11 is a connector, and 12 is a hole provided for connecting an I/O terminal group provided on the back surface of the multi-chip wiring board 2 to the connector 11. This embodiment has a structure assuming a bin type I/O extraction which has been commonly used in the past.

In this embodiment, a plurality of LSI chips 1 mounted on a case are mounted on one surface of a multi-chip wiring board 2, and the multi-chip wiring board 2 and the upper In an electronic circuit package having a structure in which a plurality of I/O terminals 3 are provided for electrical signal connection with the mounting level (here, the motherboard 7), a plurality of I/O terminals 3 are grouped into one. , and the plurality of terminal groups are distributed and mounted on the surface opposite to the LSI chip 1 mounting surface of the multichip wiring board 2, and furthermore, in the area where no terminal group is mounted, the LSI mounted on the multichip wiring board 2 is mounted. In order to dissipate the heat generated in the chip 1, a thin heat sink 9 containing a heat vibrator is in thermal contact with the surface of the multi-chip wiring board 2 facing the surface on which the LSI chip 1 is mounted.

The multi-chip wiring board 2 is covered with a sealing cap 4 on the mounting surface of the LSI chips and chips, and is sealed in a sealing cap ring 8 by racer welding or the like. Each person 12 of thin heat sink 9
passes through each group of I/O terminals 3, and
It has a size that allows it to pass through the height portion that fits into the connector 11 or the I/O terminal 3 in the connected state. This results in
Thin heat sink 9 is arranged between multichip wiring board 2 and motherboard 7. Further, the thin heat sink 9 is formed to be thicker than the multi-chip wiring board 2, and an air-cooled heat sink/O is provided in the peripheral portion protruding from the multi-chip wiring board 2.

The operation and effects of the first embodiment configured as above will be described.

In this embodiment, the heat generated by the LSI chip 1 is transmitted via the multi-chip wiring board 2 to the thin heat sink 9 that has a built-in heat vibrator, and is further led to the air-cooled heat sink/O provided at both ends of the heat vibrator 9. The heat is dissipated to the outside. In this case, if a normal metal material is used in place of the heat sink 9, its thermal conductivity will be low, resulting in an increase in thermal resistance.In this example, a heat pipe is used. Its thermal conductivity is one to two orders of magnitude higher than that of metal materials, so it can transport heat over long distances with low thermal resistance. Therefore, there is an advantage that even if the air-cooled heat sink/O is provided on both sides of the multi-chip wiring board 2, it will not become a bottleneck for heat radiation.

FIG. 5 is a diagram quantitatively showing the effects of the present invention, when I/O is extracted from the periphery of the multi-chip wiring board 2 as in the conventional structure (broken line and dashed-dotted line).
and the length of one side of the multi-chip wiring board 2 and the size of the multi-chip wiring board 2 corresponding to the size of the multi-chip wiring board 2 when performing I/O extraction in a plane as in the embodiment of the present invention (solid line).
This figure shows the relationship between the total number of I/O terminals that can be obtained from . Here, the total number of I/O terminals according to the present invention is I/O
Terminal pitch: 1.27 mm square lattice I7O terminal group is calculated as: /O01 / O/ Gap between 14 mm square I/O terminal groups (portion in thermal contact with heat vibration type heat tank) L8+n+n. As is clear from the figure, the structure according to the present invention becomes advantageous in terms of the total number of I/O terminals that can be used when the external dimension 50) of the multi-chip wiring board 2 is exceeded; for example, in the case of /O0av+square Therefore, it is possible to secure approximately twice the number of r/○ terminals compared to the conventional structure (compared here with the type produced at a pitch of 05 mm), and approximately three times as many in the case of 150 fflff1 square.

Furthermore, Figures 6(a) and (b) show the thermal resistance (from the LSI junction to the air) when the structural specifications are the same as in Figure 5 and the heat dissipation area is the same as that of the air-cooled heat sink/O. This is a comparison of thermal resistance). At this time, the air-cooled heat sink shows the results when a cooling method using air blowing is adopted. Note that the chip location in the figure is the mounting position number of LSI chip 1 shown in (a) (
1).

It corresponds to (2),... In this embodiment, since the thin heat sink 9 is not thermally connected to the entire back surface of the multi-chip wiring board 2, the heat generated in the LSI chip 1 is not directly transmitted to the heat sink 9, but is condensed at one end. The structure is such that the information is transmitted to the heat sink 9. Therefore, although the thermal resistance of this portion increases, as is clear from the figure, the increase is slight, and is only about 0%. Therefore, it can be concluded that the number of I/O terminals can be significantly increased compared to the conventional structure, and the cooling capacity can be maintained at the same level as the conventional method.

A second embodiment of the present invention based on the first embodiment will be described below.

FIG. 7 is a sectional view showing a second embodiment of the present invention, and 13 is a thin heat sink 9 with a built-in heat pipe.
This is a flexible heat vibrator for thermally coupling an air-cooled heat sink/O. The other members are the same as those with the same symbols in the first embodiment, and this embodiment has almost the same multi-chip wiring board structure and thin heat sink structure with a built-in heat pipe as in the first embodiment. It becomes. However, in the case of the first embodiment, the multichip wiring board 2
However, in this case, if an air-cooled heat sink IO were present, it would occupy a wasted area on the motherboard 7. Therefore, in this embodiment, the upper part of the multi-chip wiring board 2 is used for heat radiation.

That is, in this embodiment, the air-cooled heat sink/O and the thin heat sink 9 with built-in heat pipes are separated, the air-cooled heat sink/O is placed on the top of the multi-chip wiring board 2, and the thin heat sink 9 is different from the first embodiment. Similar to the example I/
A multi-chip wiring board 2 is provided with a hole passing through the O terminal 3.
and the motherboard 7, a thin heat sink 9 with a built-in heat pipe and the air-cooled heat sink/O are connected by a flexible heat pipe 13, and the air-cooled heat sink/O can be opened to both sides. do.

With the above structure, according to this embodiment, it is possible to reduce the area occupied by the air-cooled heat sink/O on the motherboard 7. In addition, since the air-cooled heat sink/O is connected to the flexible heat vibrator 13, it can be opened on both sides of the multi-chip wiring board 2, thereby separating the multi-chip wiring board 2 from the motherboard 7 and connecting the wiring board 2. can be easily replaced. In this embodiment, although the distance between the thin heat sink 9 with a built-in heat vibrator and the air-cooled heat sink/O is longer than that in the first embodiment, the heat vibrator 13 is used for connection between them. Therefore, the thermal resistance is negligibly small, and the cooling capacity can be kept almost the same as in the first embodiment.

Next, a third embodiment of the present invention, which is also based on the first embodiment, will be described. FIG. 8 is a top view showing a third embodiment of the present invention, in which 14 is a manifold provided at the end of the heat sink 9 containing a built-in heat vibrator, 15 is a heat vibrator, and 15a constitutes the heat vibrator 15. An evaporation pipe through which evaporated gas passes; 15b is a return pipe through which the working liquid liquefied in the heat radiation section of the heat vibrator 15 returns; 16 is a fan for cooling the air-cooled radiator;
7 is an air-cooled radiator for liquefying the working fluid in the heat pipe. The multi-chip wiring board 2 and the heat vibrator 9 having a built-in heat vibrator of this embodiment have the same structure as that of the first embodiment or the second embodiment.

In this embodiment, the air-cooled heat radiator 17 is arranged far from the multi-chip wiring board 2, and the heat sink 9 is a heat vibrator 15 consisting of an evaporation pipe line 15a and a return pipe line 15b at the end manifold 14.14. The structure is such that only cooling heat vibrator conduits 15a and 15b are arranged near the multi-chip wiring board 2.

With the above structure, it is possible to arrange a plurality of mother ports 7 on which multi-chip wiring boards 2 are mounted close to each other. In this embodiment, the gas that absorbs the heat generated by the LSI chip 1 and evaporates flows through the evaporation pipe 15a, is cooled by the fan 16 in the air-cooled heat radiating section 17, and returns to the working fluid.
The LSI chip 1 is returned to the thin heat sink 9, and the LSI chip 1 can be cooled again. Here, since the heat vibrator 15 with high thermal conductivity is used between the air-cooled heat dissipation part/O and the multi-chip wiring board 2, heat is transferred over a long distance with low thermal resistance as in the second embodiment. It has the advantage of being transportable and having a high cooling capacity to dissipate the heat generated in the LSI chip 1.

Next, a fourth embodiment of the present invention will be described.

FIG. 9 is a diagram showing a fourth embodiment according to the present invention,
18 is a fan for air cooling heat exchange of the secondary refrigerant constituting the liquid supply device, 19 is a compressor for the secondary refrigerant cooling system using a refrigeration cycle, 20 is an expansion valve for the secondary refrigerant cooling system, and 21 is the primary A heat exchanger for exchanging heat between the refrigerant and the secondary refrigerant, 22 a tank for the primary refrigerant, 23 a pump for circulating the primary refrigerant, 24 the primary refrigerant from the liquid supply device to the square multi-chip wiring board A liquid cooling pipe 25 is provided for connecting up to a heat sink 25 provided directly below the multi-chip wiring board 2, and 25 is a heat sink having a built-in liquid cooling pipe provided directly below the multi-chip wiring board 2. In this embodiment, the structure of the multi-chip wiring board 2 is the same as that of the first embodiment, and the structure of the heat sink 25 with a built-in liquid cooling pipe is the same as that of the first embodiment or the second embodiment. The structure is similar to that of the thin heat sink 9 in the example.

In this embodiment, the first. Second. Unlike the structure of the third embodiment in which the air is finally cooled via a heat vibrator, a liquid-cooled heat sink 25 is provided directly under the multi-chip wiring board 2, and the heat generated in the LSI chips is multi-layered. It is transmitted to the primary refrigerant via the chip wiring board 2. In direct cooling using such a liquid, the heat transfer coefficient is 1 compared to air cooling.
~2 orders of magnitude higher value can be obtained, and the temperature of the liquid refrigerant (primary refrigerant) sent from the liquid supply device is as low as room temperature as a result of being cooled by the secondary refrigerant, and it is generated in the multi-chip wiring board 2. Even after heat is removed, the temperature rise is extremely small due to the high heat capacity of the liquid refrigerant. Therefore, in this embodiment, the I/O is
It is possible to significantly increase the number of terminals.

In the above embodiments, the LSI chip mounted on the wiring board 2 may be a bare chip in addition to a chip mounted on a case. Further, the end portion of the heat sink 9 provided with the air-cooled heat sink/O may be on one side, both sides, or the entire circumference. As described above, the present invention can be applied in various ways in accordance with its gist and can take various embodiments.

[Effects of the Invention] As is clear from the above explanation, according to the electronic circuit package of the present invention, I/O terminals can be taken out from the wiring board on which many chips are mounted, so that the I/O
Compared to structures that extract O, the total I/O is significantly reduced.
Not only can the number of terminals be increased, but the structure also allows heat pipes or liquid-cooled heat sinks, which are heat-conducting parts, to be appropriately thermally contacted with the wiring board, making it possible to use conventional electronic circuit packages despite the small amount of thermal contact. The effect is that it is possible to obtain a high cooling capacity equivalent to or higher than that of the above.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of the present invention;
The figure is a sectional view showing the first embodiment, and FIG.
4 is a diagram showing the structure of the LSI chip mounting surface of the first embodiment, FIG. 4 is a diagram showing the structure of the back side of the multi-chip wiring board of the first embodiment, and FIG. 5 is a diagram quantitatively showing the effects of the present invention. Figures 6(a) and 6(b) are diagrams showing the relationship between the external dimensions of the multi-chip wiring board and the total number of ■/○ terminals that can be extracted from the multi-chip board. This is a diagram representing L mounted on a multi-chip wiring board.
A diagram showing the relationship between the mounting position of an SI chip and thermal resistance, FIG. 7 is a cross-sectional view of a multi-chip module showing a second embodiment of the invention, and FIG. 8 is a diagram showing a third embodiment of the invention. FIG. 9 is a diagram showing the LSI chip mounting surface structure of the multi-chip module, and FIG. 9 is a diagram showing the fourth embodiment of the present invention, and is a diagram showing the LSI chip mounting surface structure of the multi-chip module. This figure is a diagram showing a cross-sectional structure of a conventional air-cooled multichip module, and FIG. 11 is a diagram showing the structure of an LSI chip mounting surface of a conventional air-cooled multichip module. l...LSI chip, 2...Multi-chip wiring board, 3...■/○ terminal, 4...Sealing cap, 6...Connector, 7...Motherboard, 8...Ring for sealing cap, 9 ...thin heat sink with built-in heat vibrator, /O... air-cooled heat sink, 11... connector,
12... Hole provided for connecting the ■/○ terminal group to the connector 11, 13... Flexible heat vibrator, 14
...Manifold, 15...Heat pipe, 15a
...Evaporation pipe line, 15b...Return pipe line, 16...Fan, 17...Air cooling radiator, 18...Fan for air cooling heat exchange of secondary refrigerant, 19...2 Compressor for secondary refrigerant cooling system, 20... Expansion valve for secondary refrigerant cooling system, 21... Heat exchanger between primary refrigerant and secondary refrigerant, 22.
...Tank for primary refrigerant, 23.. Pump for circulating primary refrigerant, 24.. Piping for liquid cooling of primary refrigerant, 25.. Heat sink with built-in liquid cooling pipe line for primary refrigerant. Figure 3 Figure 4 Figure 5 Figure 7 Figure 1θ

Claims (3)

[Claims] (1) At least one bare chip or a chip mounted in at least one case is mounted on a wiring board, and a plurality of I/O terminals and/or power supply terminals are provided on the wiring board to connect it to an upper mounting level. In an electronic circuit package having a structure for electrical connection, some of the I/O terminals and/or power supply terminals are grouped, and at least one or more of the groups are distributed and mounted on the wiring board, and the terminals of the wiring board An electronic circuit package characterized in that a heat sink with a built-in heat pipe is brought into thermal contact with an area where the group is not mounted. (2) The electronic circuit package according to claim 1, characterized in that an air-cooled heat sink is provided at an end of the heat sink having a built-in heat pipe. (3) The electronic circuit package according to claim 1, wherein instead of the heat sink having a built-in heat pipe, a liquid cooling type heat sink is brought into thermal contact with the wiring board.