JPH04256349A - Cooling structure of board - Google Patents

Abstract

PURPOSE:To provide structure which cools, by a liquid cooling operation, a board on which a wafer-scale IC has been mounted by a method wherein the structure is constituted of a specific board a specific cold plate, a first specific coolant and the like and heat of the first coolant to which heat of the board has been conducted is exchanged with a second coolant. CONSTITUTION:The title structure is constituted of the following: a board 1 where a wafer-scale IC 3 provided with a plurality of IC's 7 has been mounted on a wafer; a cold plate 2 which is provided with water passages 8 for a second coolant 19 and with caps 10 so as to protrude into the water passages 8 and to correspond to the IC's 7 at the inside and which is sealed hermetically with reference to the board 1; and a first coolant 18 which is sealed in the space between the board 1 and the caps 10 at the cold plate 2. Heat of the first coolant 18 to which heat of the board 1 has been conducted is exchanged with the second coolant 19. For example, heat generated form a wafer-scale IC 3 is conducted to a silicone oil 18, the warmed silicone oil 18 is raised to the upper part at the inside of caps 10, the heat is exchanged with cooling water 19 flowing in water passages 8, and the IC is cooled.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for a substrate, and more particularly to a cooling structure for a substrate on which a wafer scale IC is mounted.

0002

2. Description of the Related Art Conventionally, as shown in FIG. 5, an LSI 54 mounted on a substrate 50 has a refrigerant supply path 53 and a refrigerant discharge path 52 inside from above. Nozzle 5 that protrudes corresponding to the mounting position of LSI 54
5 and a bellows 56 that allows variations in mounting of the LSI 54.

When refrigerant is supplied into the cold plate 51, the refrigerant injected from the nozzle 55 hits the heat transfer plate 6.
The LSI 54 mounted on the board 50 was cooled by exchanging heat with the LSI 54 through the board 50 .

However, with the recent trend toward higher density, instead of LSIs mounted on a substrate, a wafer scale IC 3, in which a plurality of ICs 7 are formed on a wafer, is mounted on the surface of the substrate 1 shown in FIG. 3. has been done.

[0005]

[Problems to be Solved by the Invention] However, there is no conventional method for cooling a substrate on which wafer-scale ICs are mounted, especially liquid cooling, which is known to have a high cooling capacity, and the operation reliability is not high. There was a sexual problem.

[0006] Accordingly, an object of the present invention is to cool a substrate on which a wafer scale IC is mounted by liquid cooling.

[0007]

[Means for Solving the Problems] The above object is to provide a substrate 1 on which a wafer scale IC 3 having a plurality of ICs 7 is mounted, a water channel 8 for a second coolant 19 inside, and a water pipe 8 that flows into the water channel 8. a cold plate 2 having a cap 10 provided to correspond to the IC 7 and sealed with the substrate 1; and the cap 1 of the substrate 1 and the cold plate 2.
a first refrigerant 18 sealed in a space between the substrate 1
This is achieved by a substrate cooling structure characterized by heat exchange using a refrigerant 19.

[0008]

In the present invention, heat generated by the substrate and wafer scale IC is transferred to the first coolant sealed between the substrate and the cap.

On the other hand, the second refrigerant flowing within the cold plate exchanges heat with the first refrigerant through the cap.

[0010] Regarding the first refrigerant in the cap (convection area), the one closer to the substrate side is naturally higher in temperature, and the temperature closer to the cold plate (inside the water channel) is compared, so convection occurs between the two. However, cooling is efficiently performed within this cap.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to FIGS. 1 to 4.

FIG. 1 is a diagram showing an embodiment of the present invention. FIG. 2 is a perspective view of the cold plate.

FIG. 3 is a perspective view of the substrate. FIG. 4 is an exploded perspective view of the cold plate.

As shown in FIGS. 1 and 3, a wafer scale IC is attached to the surface of a circular substrate 1 via an adhesive 11.
3 is mounted, and on the surface of the wafer scale IC3,
IC7s are formed in a matrix. The wafer scale IC 3 and the substrate 1 are wired by wires 5, and bolt holes 15 are formed in the substrate mounting housing 4 at the edge of the substrate 1 and fastened with bolts 20. Incidentally, I/O pins 12 for power supply or signal supply are set up on the back side of the board 1.

On the other hand, as shown in FIGS. 2 and 4, the cold plate 3 for cooling the wafer scale IC 3 has a recess 2b formed on the back side of the surface facing the substrate 1.
A hole 2c into which a cap 10 (described later) is inserted is bored corresponding to the insertion position of the cap 10. Note that this recess 2c serves as a water channel 8 through which the second refrigerant 19, for example cooling water, flows. Furthermore, this cold plate 2
A seal groove 13 is formed on the side surface of the substrate to which a seal 6 is attached over the entire circumference in order to improve airtightness with the substrate 1, and a seal groove 13 is formed in the recess 2b to form a water channel 8. A lid 2a having nipples 16, 16 to which cooling water is supplied or discharged is attached so as to cover the recess 2b. Furthermore, this cold plate 2
and the lid 2a are fastened together with bolts 14, as shown in the perspective view of FIG.

Cold plate 2 with cap 10
On the other hand, when injecting the first coolant 18, such as silicone oil, turn over the cold plate 2 so that the substrate 1 side faces up, and in this state, inject the silicone oil 18.
inject. Then, the silicone oil 18 is injected into the substrate 1 shown in FIG. 3 by immersing the wafer scale IC 3 in the silicone oil 18 and fastening the substrate mounting housing 4 to the cold plate 2 with bolts 20. When injecting the silicone oil 18, it is desirable not to completely inject the silicone oil 18 into the cap 10 without any air being mixed in, but to inject it so that some air is mixed in. As shown in FIG. 1, this mixed air remains as gas 9 within the cap 10, and this gas 9 prevents the silicone oil 18 from expanding.

Next, the cooling effect of the present invention will be explained using FIG. FIG. 1 shows a state configured as described above (a state in which it has been turned over again to obtain a normal arrangement).

In this state, cooling water 19 is injected from the nipple 16 on the coolant supply side. On the other hand, if the wafer scale IC 3 is operated at the time when the cooling water 19 is injected, heat is generated due to the operation of the IC 7 of the wafer scale IC 3.

The heat generated from the wafer scale IC 3 is transferred to the silicone oil 18, and the heated silicone oil 18 rises upward within the cap 10. Since this cap 10 enters the water channel 8 in the cooling water 19, it is cooled by heat exchange with the cooling water 19 flowing in the water channel 8, and then descends downward in the cap 10 again. . That is, the inside of the cap 10 corresponding to the IC 7 becomes a convection area 17, and the silicone oil 18 is convected. Therefore, natural convection is actively generated within the cap 10, and the wafer scale IC 3 is efficiently cooled.

As mentioned above, in the case of the wafer scale IC 3, the IC 7 is directly exposed, so if the cooling water 19 is applied directly, there is a possibility of a short circuit due to dust in the cooling water 19, but in this embodiment, Instead of applying cooling water 19 directly, apply silicone oil 18 that does not have a negative effect on the wafer scale IC 3, and then apply cooling water 19.
9 is cooled through the cap 10, so there is no fear of short circuits and the reliability is improved.

In the above example, as is clear from FIGS. 2 to 4, the substrate 1 and the cold plate 2 themselves are circular, but the shape is not limited to this, and other square shapes may be used. It's okay.

[0022]

As described above, according to the present invention, it is possible to cool a substrate having a wafer scale IC mounted on its surface, which has been particularly seen in recent years, with a liquid having excellent cooling efficiency, thereby improving operational reliability. Improves sex.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a perspective view of a cold plate.

FIG. 3 is a perspective view of a substrate.

FIG. 4 is an exploded perspective view of the cold plate.

FIG. 5 is a diagram showing a conventional example.

[Explanation of symbols]

1 Substrate 2 Cold plate 3 Wafer scale IC 7 IC 8 Water channel 10 Cap 18 First coolant (silicon oil) 19 Second coolant (cooling water)

Claims (1)

[Claims] [Claim 1] A substrate (1) on which a wafer scale IC (3) having a plurality of ICs (7) is mounted on the wafer.
The board (1) has a water channel (8) for the second refrigerant (19) therein, and a cap (10) provided to correspond to the IC (7) that plunges into the water channel (8). ), and a first refrigerant (18) sealed in a space between the substrate (1) and the cap (10) of the cold plate (2). , the first refrigerant (18) to which the heat of the substrate (1) has been transferred is transferred to the second refrigerant (1).
9) A substrate cooling structure characterized by heat exchange.