JPS6046056A - Cooling structure - Google Patents

Abstract

PURPOSE:To improve cooling capacity in a cooling structure for cooling a heat sink unit such as an LSI placed on a substrate by contacting under pressure a semispherical cap contacted with the unit and a stud projected at one end to a liquid coolant passage. CONSTITUTION:Heat generated from heat sink units such as a plurality of LSIs or LSI chip carriers 1' mounted on a high density LSI substrate 2 is dissipated in a route of a cap 6, a stud 7 and liquid coolant 13 in the passage of a cold plate 8, and the total thermal resistance of the route depends upon the magnitude of the contacting thermal resistance R of the cap 6 with the stud 7. The contacting surface of the cap 6 with the stud 7 is formed in a spherical shape, pressed by a spring 10, and the contacting area and pressure are increased. Accordingly, the roundness of the round corner can be reduced, the temperature difference from the coolant 13 to a heat generator 1 can be reduced, and the temperature of an LSI1' can be suppressed to limiting temperature or lower.

Description

[Detailed description of the invention] The invention is based on large-scale integrated circuits (μ, LSI) mounted on a substrate.
It relates to a cooling structure for cooling a heating element such as

Conventionally, in this type of cooling structure, the LS of the LSI board
A heat sink is attached to the non-I mounting surface, and is forcedly cooled by a blower.The heat generated from the LSI is conducted to the heat sink via the LSI board, and is transferred from the heat sink to the air.

Generally, LSIs have strict temperature limits in order to guarantee their operation, and the temperature of the LSI must be kept below a certain temperature limit. Nowadays, as the annual accumulation of LSIs increases dramatically, the amount of heat generated by them also tends to increase, and it is no longer possible to keep the temperature of LSIs below the above-mentioned limit temperature simply by increasing the size of the blower. An object of the present invention is to provide a cooling structure with a large cooling effect.

The structure of the present invention is a cooling structure for cooling a heating element such as a large-scale integrated circuit mounted on a substrate. Each of the cooling structures has a flat part and a spherical part, and the flat part connects with the heating element directly or through an intervening object. at least one hemispherical cap in contact with C, a rod-shaped stud whose one end is in surface contact with the spherical portion of the cap directly or through an intervening object, and the other end of the stud having a channel through which a liquid refrigerant flows. The cold plate is constructed of a cold plate projecting into the flow path, and pressure contact means for bringing the spherical portion of the cap into pressure contact with one end of the stud.

Next, the present invention will be explained in detail with reference to the drawings.

Referring to FIG. 1 and FIG. 2, which is a partial sectional view taken along line A-A in FIG.
A high-density LSI board 2 on which a heating element such as I' or an LSI chip carrier 1' is mounted on a contacting means such as soldering is electrically connected to the high-density LSI board 2 via a high-density connector 3. a high-density printed board 4, a hemispherical cap 6 fixed to a heat conductor 5 such as solder to a heating element l, and a surface facing the spherical part of the cap 6 as the spherical part a rod-shaped stud 7 formed into a spherical surface of the same degree of curvature; a cold plate having a flow path through which liquid refrigerant 13 flows, and the stud 7 protruding into the flow path;
Press one end of the stud 7 into the flow path of the cold plate 8, the inlet/outlet ports 11 and 12 of the liquid refrigerant 13, and press the star rad 7 and the cap 6 into contact with each other. It is composed of a spring 1o and a shell.

In FIG. 2, the heat generated by the heating element 1 is radiated directly through the cap 6, the stud 7, and the liquid refrigerant 13.
The total thermal resistance R of this path can be expressed as follows.

R=R,. +R80R, -8+ R8+R, -c Song・
-(1) Here, Rc-0: Thermal resistance from the heating element J to the cap 6 Ro: Conductive thermal resistance inside the cap 6 Rc-s ” Contact thermal resistance between the cap 6 and the stud 7 R8: The thermal resistance of the stud 7 Conduction heat resistance Ra-c: , ly F” 7 il, yo. Ya, 3
fart. A. Since the thermal resistance heating element 1 and the cap 6 are fixed with a good heat conductor 5 such as solder, Ro-8 is small.

Since the cap 6 and the stud 7 are made of a metal with high thermal conductivity, such as copper, aluminum, or molybdenum, Ro and R8 are very small and can be ignored. Since it is in direct contact with the liquid refrigerant 13, it is small. Therefore, the total thermal resistance R depends on the magnitude of the contact thermal resistance Rc-s between the cap 6 and the stud 7. In the embodiment, the contact surface between the cap 6 and the stud 7 is made spherical and pressed by the spring 1o, thereby increasing the contact area and contact pressure, so that Rc-s can be reduced. By filling the contact surface between the cap 6 and the stud 7 with grease, etc., which has good thermal conductivity, it is possible to further improve the radius.
o-8 can be made smaller. As explained above, in this example, the total thermal resistance R is very small, and the liquid refrigerant 1
The temperature difference between the heating element 3 and the heating element 1 can be reduced, and the temperature of the LSI' can be kept below the limit temperature. Furthermore, by making the contact surface between the cap 6 and the stud 7 spherical, the heating element 1 is tilted, as shown in FIG.
Even if mounted on the board 2, the cap 6 and stud 7
The contact thermal resistance R0-8 is kept small and the overall heat dissipation system is not affected at all.

Next, referring to FIG. 4, the second embodiment of the present invention has the same structure as the first embodiment except that the cap 6 is not fixed to the heating element 1. In such a configuration, even if the stud 7 is misaligned with respect to the heating element 1, the cap 6 moves by the amount of misalignment, as shown in FIG. Good contact can be maintained. Furthermore, by filling the contact surface between the heating element 1 and the cap 6 with grease or the like having good thermal conductivity, it is possible to achieve a low thermal resistance comparable to that obtained when the heating element 1 and the cap 6 are fixed together. If such a structure is adopted, manufacturing precision of parts can be relaxed.

As described above, the present invention has the effect of improving cooling capacity.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the IL of the present invention, and FIGS. 2 and 3 are partial sectional views taken along the line A-A in FIG.
The figure is a partial sectional view showing a second embodiment of the invention. In the figure, 1... Heating element% 1'...
LSI or LSI chip carrier, 2... High-density LSI board, 3... High-density connector, 4.
...High density printed board, 5... Good thermal conductor such as solder, 6... Cap, 7...
・Stud%8・・・・・・Cold plate%9・
...Patsukin, 10...Spring, 11...
...Inflow port, 12...Outflow port, 13...
...Liquid refrigerant. 1 Figure 1 #2 Concave 5υ Figure 3 Figure 4

Claims (1)

[Claims] In a cooling structure for cooling heat generating elements such as a plurality of large-scale integrated circuits mounted on a substrate, each has a flat part and a spherical part, and the flat part contacts the heating element directly or through an intervening object. a rod-shaped stud whose one end is in surface contact with the spherical portion of the cap directly or through an intervening object; and a rod-shaped stud having a flow path through which a liquid refrigerant flows inside, and the other end of the stud having a flow path through which a liquid refrigerant flows. 1. A cooling structure comprising: a cold plate protruding from the top; and pressure contact means for bringing the spherical portion of the cap into pressure contact with one end of the stud.