JPH0617312Y2 - Semiconductor device cooling structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] Regarding a cooling structure for cooling an LSI module, a plurality of LSIs are mounted on a multilayer ceramic substrate for the purpose of improving the reliability of the cooling structure. After a metallizing process is applied to the periphery of an LSI module formed by projecting a plurality of lead pins for circuit connection with the LSI on the back surface, a metallized layer of the LSI module and a damper of a flange formed by welding a plate and a damper. After welding the horizontal part with high temperature solder,
In a cooling structure in which the flange is screwed to the bottom of the cooling container via an O-ring to form a sealed container, and a refrigerant is enclosed in the sealed container, a damper of a flange for fixing the LSI module to the cooling container is provided. A cooling structure for a semiconductor device is configured by welding a damper vertical portion having a smaller thickness than conventional and a damper horizontal portion thicker than conventional.

[Industrial application field]

The present invention relates to a semiconductor device cooling structure having improved reliability.

In order to process a large amount of information quickly, semiconductor devices, which are the main components of information processing devices, have been integrated by miniaturization of unit elements, and LSIs and VLSIs have been put to practical use.

In addition, the packaging method has also been improved. Conventionally, each semiconductor chip was stored in a hermetically sealed package and mounted on a printed wiring board, but with the progress of passivation technology, many semiconductor chips have been adopted. There is a form in which an LSI module is densely mounted on a ceramic multilayer wiring board, and this is mounted on the wiring board as a replacement unit.

Since such an LSI module consumes a large amount of power during use, it generates a large amount of heat. With the conventional forced air cooling structure, it is no longer possible to keep the amount of heat generated by a semiconductor chip within the maximum operating temperature of 85 ° C. It was

From the above, a liquid cooling structure is required for the semiconductor device cooling method in place of the conventional forced air cooling.

[Conventional technology]

FIG. 3 is a sectional view showing a cooling structure of a semiconductor device,
As described above, the LSI module 1 is configured to include a plurality of LSIs 3 on the upper surface of the multilayer ceramic substrate 2 and a plurality of lead pins 4 on the lower surface, and the damper 6 of the flange 5 and the high melting point solder on the periphery of the lower surface. It is welded using.

The flange 5 is pressed against the cooling container 8 via the O-ring 7 with the screw 9.

Next, a cooling medium 10 is enclosed in the cooling container 8, and cooling water 11 circulates in the cooling container 8 having a double lid structure to cool the cooling medium 8.
Configured to cool 10.

The operation of such a cooling structure includes the LSI module 1
Is used by connecting it to an external circuit by inserting the lead pin 4 into a socket (not shown), but the LSI 3 whose temperature has risen due to heat generation is cooled by the refrigerant 10, and the refrigerant 10 is eventually heated. Then, boiling starts from the contact interface of LSI3.

Then, the gas of the boiling refrigerant 10 fills the space 12 between the refrigerant 10 and the cooling container 8, but since the cooling container 8 is cooled by the cooling water, it gradually liquefies and drops into the refrigerant 10. Evaporation and liquefaction are repeated, and liquid cooling of LSI 3 continues due to the latent heat of vaporization.

Liquid cooling of the LSI module 3 is performed in this way,
For that purpose, it is necessary that the flange 5 and the LSI module 1 are completely joined and that no liquid leaks.

FIG. 2 is a partially enlarged view showing a joint state of the conventional flange 5 and the LSI module 1. The flange 5 is formed by laser welding a thick plate 14 and a damper 6 having an L-shaped cross section. Therefore, a method of welding the horizontal portion of the damper 6 and the metallized layer 15 of the multilayer ceramic substrate 2 with high-temperature solder 16 is used.

However, since the damper 6 has a thin thickness of about 0.4 mm, it is difficult to obtain sufficient flatness when press-molding it into an L-shaped cross section, and a solder with good airtightness when joined to the multilayer ceramic substrate 2. Difficult to join.

The damper 6 is deformed by the stress generated when the plate 14 of the flange 5 is fastened to the cooling container 8 via the O-ring 7, and the joint with the multilayer ceramic substrate 2 is easily broken.

There was such a problem, and it was necessary to solve it.

[Problems to be solved by the invention]

As mentioned above, when making the damper by press molding,
There is a problem that sufficient flatness cannot be obtained and that the joint portion with the multilayer ceramic substrate is broken by the stress generated when the flange is screwed and fixed to the cooling container.

[Means for solving problems]

The above problem is that after mounting a plurality of LSIs on a multilayer ceramic substrate and projecting a plurality of lead pins for circuit connection with the LSI on the back surface of the multilayer ceramic substrate, the periphery of the LSI module is metalized. After welding the metallized layer of the LSI module and the horizontal part of the flange of the flange formed by welding the plate and the damper using high temperature solder, the flange is screwed to the bottom of the cooling container via the O-ring. In a cooling structure in which a sealed container is stopped and a refrigerant is enclosed in the sealed container, a damper of a flange for fixing the LSI module to the cooling container has a thinner vertical portion and a damper vertical portion than the conventional one. This can be solved by adopting a cooling structure for a semiconductor device, which is formed by welding a thick damper horizontal portion.

[Action]

The conventional structure absorbs the stress generated when fixing the flange to the cooling container by using a damper having a small thickness.

However, if the thickness of the damper is reduced, the flatness of the press molding will decrease and the degree of bonding with the multilayer ceramic substrate will decrease, so it will be halfway, so a thickness of about 0.4 mm is used. However, the above-mentioned problems occurred.

Now, in the cooling structure shown in FIG. 3, in addition to the stress generated when the flange 5 is fastened and fixed to the cooling container 8, the stress generated by the difference in the thermal expansion coefficient between the cooling container 8 and the multilayer ceramic substrate 2 is Yes, these must all be absorbed by the damper 6 of the flange 5.

That is, from the viewpoint of weight reduction, an aluminum (Al) alloy is often used as the cooling container, but the thermal expansion coefficient of this Al alloy is about 23 × 10 ⁻⁶ / K, while that of the glass ceramic substrate The coefficient of thermal expansion is very different, 4.0 × 10 ^-6 / K.

Therefore, in the present invention, as shown in FIG. 1, a damper vertical portion 18 and a damper horizontal portion 19 are welded and used instead of the conventional damper made by press molding.

Further, the damper vertical portion 18 is made thinner than before so that the stress can be sufficiently absorbed, and the damper horizontal portion 19 is made of a material thicker than before so as to have sufficient flatness.

By doing so, the conventional problems can be solved.

〔Example〕

As a material of the plate 14, the damper vertical portion 18 and the damper horizontal portion 19 which constitute the flange 5 shown in FIG. 1, 42 alloy is used.
(Fe-42% Ni) was used, the damper vertical portion 18 was made of a material having a thickness of 0.3 mm, and the horizontal damper portion 19 was made of a material having a large thickness of 3.0 mm.

Then, laser welding is used to weld the plate 14 and the damper vertical portion 18, and the damper vertical portion 18 and the damper horizontal portion 19, and the two are adhered to each other with a jig so that there is no gap, and an argon (Ar) atmosphere is used. Among them, using pulse YAG laser welding machine, pulse width 3-4ms, pulse speed 60pps, average output 300
Welding was performed under the conditions of W and welding speed of 8.4 mm / s.

Then, as in the conventional case, the high temperature solder 16 and the metallized layer 15 provided on the periphery of the multilayer ceramic substrate 2 are used for soldering, and then the Ov ring 7 and the cooling container 8 are pressure-bonded and fixed. The cooling structure was completed.

Regarding the cooling structure formed in this way, -50 to 12
After repeating the thermal shock test at 5 ° C, the airtightness test was performed. The airtightness was 1 × 10 ^-8 atm · cc / s or less, and the adhesion between the damper horizontal portion 19 and the multilayer ceramic substrate 2 was It was also possible to prove that the damper vertical portion 18 sufficiently absorbs the stress.

[Effect of device]

As described above, by implementing the present invention, it is possible to improve the reliability of the cooling structure of the semiconductor device in which the LSI module is cooled and used.

[Brief description of drawings]

1 is a partially enlarged view of a cooling structure having a flange according to the present invention, FIG. 2 is a partially enlarged view of a joint portion between an LSI module and a flange, and FIG. 3 is a sectional view showing a cooling structure of a semiconductor device, Is. In the figure, 1 is an LSI module, 2 is a multilayer ceramic substrate, 3 is an LSI, 5 is a flange, 6 is a damper, 7 is an O-ring, 8 is a cooling container, 9 is a screw, 14 is a plate, 15 is a metallized layer, 16 Is high temperature solder, 18 is a vertical part of the damper, and 19 is a horizontal part of the damper.

Claims (1)

[Scope of utility model registration request] 1. A plurality of layers are provided on a multilayer ceramic substrate (2).
A metallization process is performed around the LSI module (1) formed by mounting the LSI (3) and projecting a plurality of lead pins (4) on the back surface of the multilayer ceramic substrate (2) for circuit connection with the LSI (3). After the application, the metallized layer (15) of the LSI module (1) and the damper horizontal portion (19) of the flange (5) formed by welding the plate (14) and the damper (6) together with high temperature solder ( After fusing with the use of 16), the flange (5) is screwed to the bottom of the cooling container (8) through the O-ring (7) to make a sealed container, and the refrigerant (10) is placed in the sealed container. In a cooling structure in which the damper module (6) of the flange (5) for fixing the LSI module (1) to the cooling container (8) is thinner than the conventional damper, the damper vertical portion (18) is enclosed. It is characterized in that the damper horizontal part (19), which is thicker than the conventional damper, is welded. Cooling structure of the conductor device.