JPH0573268B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a heat dissipation structure for an electronic circuit package, and in particular to a structure for efficiently dissipating heat from a high-density integrated circuit element (hereinafter referred to as LSI) that generates a large amount of heat. Regarding structures that dissipate heat.

[Prior Art] An electronic circuit package that constitutes an electronic device is generally constructed by mounting a large number of LSI and other electronic circuit components on a wiring board, and is forced to cool down by a cooling fan attached to the electronic circuit package housing rack. It has an air-cooled structure. However, especially in large-scale information processing equipment, LSI elements are becoming more highly integrated and faster in order to improve the performance of the equipment, and they are also mounted in high density on wiring boards, so LSI and electronic circuit packages are The amount of heat generated and the density of heat generated have increased significantly, and conventional forced air cooling is no longer able to provide sufficient cooling. That is, in order to cool an LSI electronic circuit package that has a high calorific value and heat density, a large amount of cooling air is required, but this is naturally limited by the capacity and noise of the cooling fan. For this reason, a heat conduction cooling structure has been adopted in which a liquid refrigerant, which has superior heat transfer performance compared to air, is circulated near the LSI, which is a heat generating part, and heat from the LSI is transferred to the liquid refrigerant by direct conduction. Ta.

Conventionally, an electronic circuit package with this type of heat dissipation structure has a cooling plate 5 mounted on the top surface of a printed circuit board 1 assembly on which a plurality of LSIs 2 are mounted, using fixtures 6 to maintain a specified interval, as shown in FIG. The structure is such that it is fixed with screws 61. Here, the cooling plate 5 has a flow path 51 through which a liquid refrigerant circulates therein, and has a pair of refrigerant inlet/outlet ports 52 connected to cooling piping (not shown) of the frame at the end thereof. Also,
A flexible conductor such as a metal spring or thermally conductive rubber is installed between the top surface of the LSI 2 and the cooling plate 5 in order to absorb warpage/twisting of the printed circuit board 1 and variation/inclination of the mounting height of the LSI 2. A heating body 7 is interposed, and the heat is dissipated from the LSI 2 through a path of the heat transfer body 7, the cooling plate 5, and the coolant 8.

[Problems to be Solved] However, in the conventional heat dissipation structure of the electronic circuit package described above, the structure or material of the heat transfer body 7 poses a problem. That is, when interposing the heat transfer body 7 made of thermally conductive rubber, heat dissipation sheet, etc. between the LSI 2 and the cooling plate 5, the thickness should be reduced as much as possible because the heat conductivity itself is very low compared to metal etc. It has to be made thinner, and therefore has less flexibility in the thickness direction, resulting in the drawback that variations in the mounting heights of the LSIs 2 must be fairly closely aligned. Furthermore, if a metal spring, bellows, etc. are used as the heat transfer body 7, variations in the mounting height of the LSI can be tolerated to some extent, but since the structure is such that force is constantly applied to the LSI 2 and the printed circuit board 1, The substrate 1 and the cooling plate 5 must be made robust so as not to warp, resulting in a disadvantage that the structure becomes complicated and the weight increases. Furthermore, in any of the heat transfer bodies 7 described above, since the cooling plate 5 and the printed circuit board assembly are stacked on top of each other, the overall thickness is increased, and a large number of electronic circuit package assemblies must be mounted three-dimensionally. If the device is housed in a large area, it has the fatal disadvantage that high-density packaging is not possible and it is difficult to achieve high performance of the device.

[Means for Solving Problems] The heat dissipation structure of the electronic circuit package of the present invention which solves the above-mentioned conventional problems includes providing screw studs on the upper heat dissipation surface of a plurality of integrated circuit elements mounted on a wiring board. , a cooling pipe through which a liquid refrigerant flows is laid between the integrated circuit elements, and both sides of a plurality of heat-conducting plates holding the cooling pipes sandwiched therebetween are screwed to the studs to form the integrated circuit element. It is configured by being fixed to the upper heat dissipation surface of the.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1a is a plan view of a heat dissipation structure of an electronic circuit package according to an embodiment of the present invention, FIG. 1b is a sectional view taken along line A-A in the same figure, and FIG. FIG. 3 is a partially enlarged exploded perspective view.

The heat dissipation structure of the electronic circuit package according to the present invention includes a wiring board 1 made of a printed circuit board or the like, a large number of LSIs 2 mounted on this board, cooling pipes 3 laid on the component mounting surface side of the wiring board, and LSIs 2. It is composed of a plurality of heat conductive plates 4 that thermally connect the cooling pipes 3.

For LSI2, the top surface of the case is the heat dissipation surface.
The LSI chip is sealed inside, and a male-threaded stud 21 is vertically brazed onto the heat radiation surface.

The cooling pipe 3 is a metal pipe (for example, a copper pipe) with good thermal conductivity through which a liquid coolant 8 such as water flows, and is adjacent to at least one side of a row of LSIs 2 arranged and mounted on the wiring board 1. A closed flow path is formed between the refrigerant inlets and outlets 31 and 32. Here, the inlet part 3 of the refrigerant 8
1. For the outlet portion 32, a self-sealing coupler or the like is used, which can be easily attached to and detached from the main piping of the refrigerant system of the rack, and which prevents the internal refrigerant 8 from leaking outside even when attached and detached.

The heat conduction plate 4 is composed of plates 41 and 42 made of two thin copper plates. These 2
The plates 41 and 42 are bent into a semicircular shape at the center so that they squeeze the cooling pipe 3 from above and below and are in close contact with each other, and the flat parts at both ends have studs 21 which are brazed on the LSI 2. A hole 43 that fits into each is drilled. These two plates 41,
After the LSI 2 is soldered onto the wiring board 1, the washer 22 and the nut 42 are attached to the top surface of the LSI 2 located on both sides of the cooling pipe 3 by sandwiching them from above and below with the cooling pipe 3 in the center. 2
3 mechanically fixed to the stud 21.

With this structure, the heat generated in LSI 2 is transferred from the heat dissipation surface of LSI 2 to the heat conduction plate 4.
By discharging heat through the heat conduction path of → cooling pipe 3 → refrigerant 8, extremely efficient cooling characteristics can be obtained. That is, by circulating the liquid refrigerant 8 in the immediate vicinity of the LSI 2 and mechanically and firmly connecting the LSI 2 and the refrigerant 8 using the heat conduction plate 4 made of a metal plate with good thermal conductivity, the heat transfer path is established. It is extremely short, and LSI 2 and heat conduction plate 4
The thermal resistance of the contact portion between the heat conductive plate 4 and the cooling pipe 3 can also be made sufficiently small.

Furthermore, by using a thin copper plate or the like for the heat conduction plate 4, even if there are variations or inclinations in the mounting height of the LSI 2 to the wiring board 1, the heat conduction plate 4 easily follows and deforms, causing the top surface of the LSI 2 to Since they are in close contact, good thermal conductivity can be obtained. In addition, by subdividing the heat conduction plate 4 by using two LSIs 2, the wiring board 1
Since no force is generated to warp the electronic circuit, structures such as stiffeners are not required, and the electronic circuit package assembly structure can be simplified and reduced in weight. Furthermore, since the cooling pipe 3 is laid in the space between the LSIs 2, the overall mounting height can be mounted at a height not much different from the mounting height of the LSI 2, and the electronic circuit package assembly can be mounted on the back panel of multiple racks. Even when three-dimensionally mounting the device, it is possible to perform high-density mounting, and the performance of the device can be improved.

In this embodiment, the heat conduction plate 4 is configured to connect the LSIs 2 on both sides of the cooling pipe 3.
If the heat generation amount of LSI2 is small, multiple LSI
2 may be connected in series, or conversely, if the LSI generates a large amount of heat and it is necessary to further improve the heat transfer characteristics, LSI 2 may be connected in series.
It goes without saying that measures such as applying thermally conductive grease to the contact interfaces between the heat conductive plate 4 and the heat conductive plate 4 and between the heat conductive plate 4 and the cooling pipe 3, or increasing the width of the heat conductive plate can be taken.

[Effects of the Invention] As explained above, the present invention provides cooling pipes between integrated circuit elements, and fixes heat-conducting plates sandwiching the cooling pipes to the upper heat dissipation surface of the integrated circuit elements. Uniform heat conduction characteristics can be obtained even if there are variations or inclinations in the mounting height of the LSI, and the heat transfer means has a relatively simple configuration, and the height does not significantly affect the component mounting height. Since it can be realized, it has excellent effects such as being able to be made smaller and lighter, and can be mounted on a rack at a higher density.

[Brief explanation of the drawing]

FIG. 1a is a plan view showing a heat dissipation structure of an electronic circuit package according to an embodiment of the present invention, FIG. 1b is a sectional view taken along line A-A in FIG. 1a, and FIG. 2 is shown in FIG. FIG. 3 is an enlarged exploded perspective view of the LSI mounting portion of the heat dissipation structure, and FIG. 3 is a side sectional view showing the heat dissipation structure of a conventional electronic circuit package. 1: Wiring board, 2: Integrated circuit element, 21: Stud, 3: Cooling pipe, 4: Heat conduction plate, 5: Cooling plate, 6: Fixture, 7: Heat transfer body, 8: Refrigerant.

Claims (1)

[Claims] 1. A stud for screwing is provided on the upper heat dissipation surface of a plurality of integrated circuit elements mounted on a wiring board, cooling pipes are laid between the integrated circuit elements through which a liquid coolant flows, and the cooling pipes are A heat dissipation structure for an electronic circuit package, characterized in that both sides of a plurality of heat conductive plates held by sandwiching are screwed to the studs and fixed to the upper heat dissipation surface of the integrated circuit element.