JP2000150752A - Cooling device of electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure corrosion resistance and mechanical strength over a long term by using aluminum nitride sintered body as a cooling jacket material and providing an ion-eliminating device for eliminating an ionization substance in a heat transfer medium in a heat transfer medium supply unit. SOLUTION: A plurality of integrated circuit units 2 are mounted on a substrate 1, and a cooling jacket 4 for cooling the integrated circuit units 2 by receiving the supply of a heat transfer medium 3 is provided on the integrated circuit units 2. In the cooling jacket 4, an aluminum nitride sintered body is used, high-temperature treatment is made in an oxidation atmosphere, and an oxide 41 with α-alumina as a main phase is formed on a water-contacting surface in the channel surface of the cooling jacket 4. Also, an ion-eliminating device 9 for eliminating the ionized substance of the heat transfer medium is provided in a heat transfer medium supply unit B with a tank 6, a pump 7, and a heat exchanger 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device for an electronic device, and more particularly to a cooling device for an electronic device that cools an integrated circuit unit by using a heat conductive medium.

[0002]

2. Description of the Related Art Aluminum nitride has been spotlighted as a heat-dissipating material by utilizing its property of having a high thermal conductivity with an increase in the amount of heat generated by increasing the output of semiconductor devices. In such an application, the aluminum nitride sintered body has a cooling surface in contact with the semiconductor element and is used by forming a cooling jacket having a cavity therein. Then, a heat conductive medium is supplied into the cooling jacket to cool the cooling surface. As the heat transfer medium, water has been generally used from the viewpoint of safety and cost.

However, when an aluminum nitride sintered body is used as a material for such a cooling jacket, and water is used as a heat transfer medium, the water contact surface of the aluminum nitride sintered body is decomposed by hydrolysis. It has a problem that it is corroded by formation and its mechanical strength is significantly reduced.

In order to solve such problems, a method of forming a coating such as α-alumina on a water-contacting surface of an aluminum nitride sintered body as a coating material, and a method of forming a coating on water from a heat conductive medium. A method has been adopted in which hydrolysis of aluminum nitride is suppressed by adding glycerin or the like.
In addition, a method of suppressing the hydrolysis of aluminum nitride by adding an organic compound having an alcoholic hydroxyl group and a pH buffer is employed.

[0005]

However, when a coating such as α-alumina is formed on the water-contacting surface of the above aluminum nitride sintered body, the corrosion resistance due to defects such as pores and micro cracks present in the coating is high. Is inadequate. In addition, when glycerin or the like is added to water, if a small amount is added, the anticorrosion effect cannot be obtained due to insufficient formation of a film on the aluminum nitride surface, or if a large amount is added, water as a heat transfer medium The ratio decreases, the thermal conductivity decreases and the viscosity coefficient increases, so the heat transfer capacity as a heat transfer medium decreases.If the same heat exchange capacity as before the addition is attempted, the capacity is higher. There was a problem that a large heat exchanger was required. When an organic compound having an alcoholic hydroxyl group and a pH buffer are added, the buffer may lower the corrosion resistance of other wetted materials. Further, with the corrosion, the mechanical strength of the base material may be significantly reduced.

As described above, when the above conventional technique is used,
The corrosion resistance and mechanical strength in the heat conductive medium of aluminum nitride have not been ensured for a long time.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors studied the case where a film such as α-alumina was formed on the water contact surface of an aluminum nitride sintered body, By controlling the quality of the water that is
It has been found that it is possible to prevent a decrease in the corrosion resistance of the underlying aluminum nitride due to defects such as pores and micro cracks existing in the film such as α-alumina.

That is, according to the present invention, an integrated circuit unit having an integrated circuit mounted on a substrate, a cooling jacket in thermal contact with the integrated circuit unit, and a tank for supplying a heat conductive medium to the cooling jacket. In a cooling device for an electronic device provided with a heat-conducting medium supply unit comprising a heat transfer medium, a pump, and a heat exchanger, an aluminum nitride-based calcination material having an oxide having α-alumina as a main phase formed on a wetted surface is used as the cooling jacket material. The present invention is characterized in that an ion removing device for removing ionized substances in the heat transfer medium is provided in the heat transfer medium supply unit using the union.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. This embodiment includes two blocks, a processor unit A and a heat conductive medium supply unit B. In the processor unit A, a plurality of integrated circuit units 2 are mounted on a substrate 1, and the integrated circuit units 2 are cooled by receiving a supply of a heat conductive medium 3 (for example, water). A cooling jacket 4 is provided. The integrated circuit unit 2 and the cooling jacket 4 have a structure in which they are in thermal contact.

[0010] The processor unit A and the heat conductive medium supply unit B are connected by a pipe 5. Heat transfer medium 3
Is discharged from the tank 6 in the heat conductive medium supply unit B, then pressurized by the pump 7 and sent to the processor unit A. Further, after cooling the integrated circuit unit 2 in the cooling jacket 4, the heat conductive medium 3 returns to the heat conductive medium supply unit B and is cooled again by the heat exchanger 8.

The cooling jacket 4 made of aluminum nitride sintered body is subjected to high temperature treatment in an oxidizing atmosphere,
An oxide 41 having α-alumina as a main phase is formed on the water-contacting surface on the channel surface of the cooling jacket 4. Since the oxidation of the aluminum nitride-based sintered body proceeds from about 1100 ° C., the high-temperature treatment is desirably performed at 1000 ° C. or higher, and when the thickness of the oxide layer is about 1 μm, the heat treatment may be performed at 1150 ° C. for 1 hour. .

Further, as the thickness of the oxide layer increases,
Cracks occur in the oxide layer due to residual stress during film formation. When cracks occur, oxidation proceeds further.
When cracks occur in the α-alumina during production or when the α-alumina film is relatively thin, the underlying aluminum nitride sintered body is exposed to a water environment and the reaction of the formula (1) is performed. Is generated.

[0013]

Embedded image AlN + 3H ₂ O → Al (OH) ₃ + NH ₃ (1) As shown in the formula (1), aluminum nitride reacts with water to form aluminum hydroxide,
Generates ammonia. Further, the following reaction proceeds.

[0014]

## STR2 ## _{NH 3 + H 2 O ⇒ NH} 4 + + OH - ... (2) When the cooling water becomes alkaline, the dissolution of α- alumina aluminum hydroxide, and water contact surface is promoted.

This embodiment is characterized in that a tank 6, a pump 7,
An ion removing device 9 for removing ionized substances of the heat transfer medium is provided in the heat transfer medium supply unit B including the cooling jacket 4, the heat exchanger 8 and the pipe line 5.

By removing the OH ^- ions generated by the formula (2) in the pure water purifier 9, the dissolution of aluminum hydroxide and α-alumina on the surface in contact with water is suppressed, so that the corrosion resistance of the cooling jacket 4 is reduced. improves. Further, by improving the corrosion resistance, the mechanical strength of the base material, which decreases with corrosion, can be suppressed. Further, by removing ammonium ions by the ion removing device 9, the corrosion resistance (for example, stress corrosion cracking resistance) of the copper-based material used in the heat exchanger 9 and the like is improved.

The ion removing device 9 is made of, for example, an ion exchange resin, and is often installed in a bypass pipe in the heat conductive medium supply unit B due to a high pressure loss and a low flow rate.

[0018]

According to the present invention, an aluminum nitride sintered body having an oxide containing α-alumina as a main phase formed on a water contact surface is used as the cooling jacket material, and the cooling jacket material is provided inside the heat conductive medium supply unit. By providing an ion removing device for removing ionized substances in the heat transfer medium, the corrosion resistance of the oxide material having α-alumina as the main phase on the water contact surface of the cooling jacket and the copper-based material used in the heat exchanger and the like are reduced. improves.
This makes it possible to supply a stable cooling device for electronic devices over a long period of time.

[Brief description of the drawings]

FIG. 1 is a cooling system diagram showing a cooling device for an electronic device according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Integrated circuit unit, 3 ... Heat conductive medium, 4
... Cooling jacket, 5 ... Piping, 6 ... Tank, 7 ... Pump, 8 ... Heat exchanger, 9 ... Ion removal device, 41 ... Oxide whose main phase is α-alumina.

Continued on the front page (72) Inventor Akio Ide 1 Horiyamashita, Hadano-shi, Kanagawa Prefecture Inside the General-purpose Computer Business Division, Hitachi, Ltd. (72) Inventor Junri Ichikawa 1-Horiyamashita, Hadano-shi, Kanagawa Prefecture, General F term in the computer division (reference) 5F036 AA01 BA10 BB21 BB41 BB46 BD13

Claims (1)

[Claims] An integrated circuit unit having an integrated circuit mounted on a substrate, a cooling jacket in thermal contact with the integrated circuit unit, a tank for supplying a heat conductive medium to the cooling jacket, a pump, and a heat pump. In a cooling device for an electronic device including a heat conductive medium supply unit including an exchanger, an aluminum nitride-based sintered body in which an oxide having α-alumina as a main phase is formed on a wetted surface is used as the cooling jacket material. A cooling device for an electronic device, further comprising an ion removing device for removing an ionized substance in the heat conductive medium in the heat conductive medium supply unit.