JPS5844754A - Cooling structure for lsi package - Google Patents

Abstract

PURPOSE:To improve the cooling capacity of an LSI package by forming a heat transfer unit of bimetal structure on an LSI, allowing it to deform at the temperature rising time and to be pressurized to a cooling module. CONSTITUTION:An LSI package is placed on a package substrate 2, two transfer units 3 of bimetal structure are fixed in U shape in section, and a cooling module 7 is interposed between frames 8 at a gap from the unit 3. Liquid coolant 4 is supplied at 5 to the module and is exhausted. Most of the heat is flowed through the unit 3 to the module 7, the unit 3 is deformed by the temperature rise of the LSI, is then pressurized to the module 7, thereby decreasing the thermal resistance, the pressing force is increased proportionally to the temperature rise, thereby further decreasing the thermal resistance, and the temperature of the unit can be maintained constantly, thereby improving the cooling capacity of the package.

Description

[Detailed description of the invention] The present invention relates to a cooling structure for an LSI package.

Large-scale integrated circuits (hereinafter referred to as L) widely used in electronic devices
It is important to maintain the temperature of an element such as 8I at a constant temperature from the viewpoint of reliability.

Conventionally, the cooling structure of the L8I package is a structure in which a heat sink is pressure-bonded or fixed to the back side of the L8I mounting surface of the LSI package board, and this is forcedly air-cooled using a blower.The heat generated from the L8I is transferred to the L8I package board. 12 conduction to the heat sink, which is conducted from the heat sink to the air.

Generally, L8I has strict temperature limits in order to guarantee its operation, and the temperature of the LSI must be kept below a certain limit. However, with the progress of semiconductor technology in recent years,
As the degree of integration of L8I is increasing dramatically, its heat generation is also increasing, and conventional cooling structures have a large thermal resistance from the heat sink to the air, making it necessary to use a large heat sink and large blower. However, the current situation is that the temperature of the LSI cannot be kept below the limit of 1A degrees.

An object of the present invention is to provide a cooling structure for an L8I package with excellent cooling capacity.

In order to achieve the above object, a cooling structure for an L8I package according to the present invention provides a cooling structure for a large number of LSIs mounted on a substrate.
In the cooling structure that diffuses and cools the heat generated by the package, etc.
Each of the L8Is is provided with at least one heat transfer body having a bimetal structure, and a cooling module that is close to or in contact with the heat transfer body and allows a liquid refrigerant to flow through the inside, and when the temperature of the L8I rises, the The heat transfer body is configured to deform and come into pressure contact with the cooling module.

According to the above configuration, the object of the present invention is completely achieved.

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

FIG. 1 is a plan view showing an embodiment of the cooling structure according to the present invention;
FIG. 2 is a sectional view taken along the line A-A in FIG. 1.

A large number of LSIIs are mounted on an LSI package board 2, and each LaI 3 has two cross-sections (3) fixed to a heat transfer body having a bimetallic structure with the opening thereof facing inside. The heat transfer body 3 and the cooling module 7 are held between frames 8.8 so as to fix the cooling module 7 with a gap between the heat transfer body 3 and the heat transfer body 3. Cooling module 7Kfl
A supply port 5 and a discharge port 6 for the liquid refrigerant 4 are provided, and the liquid refrigerant 4 flows through the inside.

The heat generated from LaI3 [, the first path that is transmitted to the surrounding air through the LSI package board 2, and the LSI
Heat is radiated through two routes: from the IK-fixed bimetal heat transfer body 3, through the cooling module 7, and the second route conducted to the liquid refrigerant 4 constantly flowing from the supply port 5 to the discharge port 6. .

However, since the thermal resistance of the first path transmitted from the L8I package board 2 to the surrounding air is very large, most of the heat is dissipated through the second path, that is, from the bimetal heat transfer body 3 to the cooling module 7. Ru.

In the second path from the bimetal heat transfer body 3 to the cooling module 7, from the LaI 3 to the bimetal heat transfer body 3 L and from the cooling module 7 to the liquid refrigerant 4 are mostly good thermal conductors, so Thermal resistance can be kept low. Since the heat transfer body has a bimetal structure in order to conduct heat from the bimetal heat transfer body 3 to the cooler Joule 7 with low thermal resistance, when the temperature of the LaI 3 increases, the bimetal heat transfer body 3 deforms and the cooling module 7 It is pressed into contact with the LSII, resulting in low thermal resistance, and as the temperature of LSII increases,
Its crimp force is increased, allowing for a lower heat resistance flower.

Although the heating element has been described above as L8I, the present invention is similarly applicable to other heating elements.

Further, the heat transfer body and the cooling module may be provided in contact with each other from the beginning.

As explained above, by employing a heat transfer body having a bimetallic structure in the heat radiation path of a heating element such as L8I, the thermal resistance of the heat radiation path decreases as the temperature rises, so the ore content of the heating element can be kept constant. This has the effect of improving the cooling capacity of the L8I package.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of the cooling structure according to the present invention;
FIG. 2 is a sectional view taken along the line AA in FIG. l...L8I 2...L8I package board 3
...Bimetal heat transfer body 4...Liquid refrigerant 5...
Supply port 6...Discharge lower...Cooling module 8...Frame patent applicant NEC Corporation representative Patent attorney I) Ro Hisashi

Claims (1)

[Claims] A large number of L 8 I mounted on the substrate, <5. In a cooling structure that diffuses and cools the heat generated by a cage, etc., a cooling module is provided that is in contact with or in contact with the liquid refrigerant flowing through the inside thereof, and when the temperature of the L8I rises, the heat transfer body deforms and the cooling module deforms. A cooling structure for an LSI package, characterized in that it is configured to be in pressure contact.