JP2536063B2 - Cold plate cooling structure - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold plate cooling structure, and more particularly to a cold plate cooling structure that is convenient for directly cooling a multi-chip module of an electronic device on which a semiconductor is mounted. It is one.

[Conventional technology]

Large-scale information processing equipment that achieves high speed dramatically increases the amount of heat generated per LSI. Therefore, the direct water cooling type is adopted, but the problems here are the required flow rate of the cooling water, the piping system and the cooling capacity. In order to keep the piping system simple, the flow rate can be saved by connecting the modules in series and flowing cooling water to each, but the non-uniform water temperature between the modules becomes a problem.

The conventional cold plate cooling structure is, for example, “NEC
As described in “Technical Report Vol.39 No.1 (1986)”, the cold plate had one inlet and one outlet for the cooling liquid, and these were connected in series by piping. That is, as shown in FIG. 5, a plurality of cold plates are used.
71, 72, 73, 74 are respectively connected in series, and when the cooling liquid is flown from the inlet, the plates 71, 72, 73, 74 flow in the order, and the water flows out from the outlet. There was a phenomenon that 73 was higher than 72 and 74 was higher than 73.

[Problems to be Solved by the Invention]

In this way, in the conventional cooling structure, when multiple cold plates are connected in series, the cold plate in the latter stage is more affected by the rise in water temperature due to the heat absorption of the cold plate in the former stage. The chip module had a cooling disadvantage. However, in the past, no consideration was given to such problems, and improvement was desired.

An object of the present invention is to solve such a conventional problem and eliminate a multi-chip module that is disadvantageous in terms of cooling among multi-chip modules that are respectively cooled by a plurality of cold plates connected in series. An object of the present invention is to provide a cold plate cooling structure capable of cooling a multi-chip module on average.

[Means for solving the problem]

In order to achieve the above object, the cold plate cooling structure according to the present invention includes a mounting rack in which a plurality of multi-chip modules having a plurality of semiconductors that generate heat are mounted on a motherboard, and the multi-chip module is incorporated into the mounting rack.
In a direct cooling structure of an electronic device including a cold plate provided with a cooling liquid flow path, the flow path of the cold plate is divided into a plurality of blocks, each block is provided with a cooling liquid inlet / outlet, and each block is Is characterized in that the cooling liquid flows in the direction opposite to the adjacent block.

[Action]

In the present invention, the number of flow paths of the cooling liquid is increased, and in that case, an additional passage is provided at a subsequent stage where the cooling liquid having a relatively high water temperature flows so that the cooling water having a relatively low water temperature flows. As a result, the temperature rise of the multi-chip module in the subsequent stage is relieved. That is, the cooling liquid flow path of the cold plate incorporated in each multi-chip module is divided into a plurality of blocks, and the cooling liquid inlet / outlet is attached to each of these blocks, so that cooling water flows in opposite directions in adjacent blocks. Assemble the piping so that the water flows.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

 FIG. 3 is a diagram showing the principle of the structure of the present invention.

When the cold plate is provided with one inlet and one outlet for the cooling liquid, the temperature of the cooling liquid rises according to the amount of heat generated by the heat generation of the multichip module to which the cold plate is attached. Therefore, this temperature rise is directly applied to the cold plate located downstream of this cold plate, which is disadvantageous in terms of cooling capacity.

As shown in FIG. 3, the cold plate 1 is divided into a plurality of blocks 1A, 1B, 1C, 1D. Here, n such cold plates (three in FIG. 3) are prepared, and the k-th block is described as kA, kB, kC, kD. These cold plates 1, 2, 3, ..., K are connected in series and the cooling liquid is flown as follows.

(Coolant) → 1A → 2A → 3A → ・ ・ kA → ・ ・ → nA → (Recovery) ← nB ← (Coolant) (Recovery) ← 1A ← 2B ← 3B ← ・ ・ kB ← ・ ・ (Coolant) → 1C → 2C → 3C → ・ ・ kC → ・ ・ → nC → (recovery) ← nD ← (coolant) (recovery) ← 1D ← 2D ← 3D ← ・ ・ kD ← ・ ・ That is, in series between the same blocks The cooling liquid is connected so that it flows, and the adjacent blocks in the same cold plate are connected so that the cooling liquid flows alternately in opposite directions.

In such a state, if the temperature rise of the cooling liquid after passing one stage through each block is Δt ₀ , (k−1) · Δt for the group kA, kC of the kth cold plate.
While the cooling liquid flows with a temperature rise of ₀ , the block kB,
The coolant with a temperature rise of (n−k) · Δt ₀ flows into the kD group. Since the two groups are alternately mixed, heat exchange between the two groups is performed, their cooling temperatures interfere with each other and are averaged, and the temperature rise felt by each cold plate is as follows.

{(K−1) · Δt ₀ + (n−k) · Δt ₀ } / 2 = (n−
_{1) · Δt 0/2 ...} (1) In practice, the value obtained by multiplying the temperature rise distribution coefficient alpha in the above equation (1), α (n- 1) · Δt 0/2 cold plate temperature rise of feel.

That is, regardless of k, i.e. regardless of the position of the cold plate, α (n-1) · Δt 0/2 cooling liquid with a temperature increase of the is equivalent to that the flows.

In the conventional cooling structure, the cold plate belonging to the most downstream is directly subjected to the temperature increase of (n-1) .Δt ₀ , but in the cooling structure of the present invention, as described above,
By averaging the temperature rises of all the cold plates in both the most downstream and the most upstream, the cooling disadvantage of the cold plates belonging to the most downstream can be eliminated.

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

The multi-chip modules 11 and 12 in FIG. 1 are mounted with a semiconductor that generates heat, and each multi-chip module 1
1, 12 are attached to cold plates 21, 22.
The left side cooling liquid 51 supplied from the cooling device passes through the pipe 4 and enters the block 31 in the cold plate 21. The pipe 4 is connected to the block 33 of the cold plate 22 in the next stage so that the cooling liquid passing through the block 31 enters. On the other hand, the pipe 34 is connected to the block 34 adjacent to the block 33 so that the right side cooling liquid flow 52 from the cooling device directly enters from the cooling device.

In the embodiment of FIG. 1, the cooling liquid flowing into the block 33 due to the heat absorbed in the block 31 is accompanied by a temperature increase, but the cooling liquid not accompanied by the temperature increase is contained in the block 34.
It is supplied directly from the cooling device. The relationship between these temperature increases will be considered next.

FIG. 2 is a diagram showing a temperature rising state at each block position in FIG.

As block positions in FIG. 2, A, A ′, B, B ′ are positions where the inlets and outlets of the cold plates 21 and 22 in FIG. 1 are cut.

As shown in FIG. 2, the temperature curve 63 of the cooling liquid flowing from the block 31 to the block 33 is the cooling temperature at the inlet A.
It rises linearly from t ₀ to the elevated temperature at the outlet B ′. On the other hand, the temperature curve 64 of the cooling liquid flowing from the block 34 to the block 32 linearly rises from the cooling temperature t ₀ at the inlet B ′ to the high temperature at the outlet A. Since heat is exchanged between the blocks of the same cold plate, the curve theoretically takes an intermediate value between the curves 63 and 64, but in actuality, the shaded area in Fig. 2 shows various conditions. It becomes the inside curve.

That is, the blocks 33 and 34 are two blocks belonging to the cold plate 22, but the temperature rise of the cooling liquid flowing into the block 33 is not accompanied by the temperature rise of the cooling liquid flowing into the adjacent block 34, so that the cold plate When viewed as a whole of 22, the mutual cooling temperatures are averaged and the liquid temperature is lowered by Δt. A similar situation occurs in the cold plate 21 and, as a result, the cold plate has no distinction between upstream and downstream.

In the embodiment shown in FIG. 1, the number of blocks of the cold plate is two, but of course, the number may be increased. Although the number of cold plates connected in series has been described as two, the same effect can be expected even if the number is further increased.

FIGS. 4A and 4B are views of a cold plate cooling structure showing another embodiment of the present invention.

In FIG. 4 (a), four blocks connected in series are connected to each other in the opposite directions as shown in FIG.
The pipes for flowing the cooling liquid are not applied, but the pipes for the one cooling liquid are applied. At that time, by bending the one pipe in the middle, the cooling liquids in the opposite directions are generated. I am making it flow.

That is, the pipes connected so as to flow from the blocks 81 to 82 are bent at the block 82, and the same block 82 is again made.
And it is passed to 81. Similarly, regarding the blocks 84 and 83, the cooling liquid that has entered from the block 84 is bent at the exit of the block 83 and flows again to the blocks 83 and 84. Even in this case, in the same manner as in the case of FIG. 1,
The temperature of the cooling liquid is averaged.

Also in FIG. 4B, two blocks are made to flow the cooling liquid from the inlet to the block 91, bend the pipe at the output, and flow again to the block 91. Similarly, the cooling liquid is made to flow from the inlet to the block 92, the pipe is bent at the output, and the cooling liquid is made to flow again to the block 92. Also in this case, since the cooling liquids flow in opposite directions in the same block, the temperatures of the cooling liquids are averaged.

〔The invention's effect〕

As described above, according to the present invention, when the cold plates are connected in series, the temperature of the cooling liquid increases as it goes downstream, but this temperature increase is averaged by causing the left and right cooling liquids to interfere with each other. Therefore, the multi-chip module which is disadvantageous in cooling can be eliminated, and the effect is great in terms of economical efficiency and maintainability.

[Brief description of drawings]

FIG. 1 is a cooling structure diagram of a cold plate showing an embodiment of the present invention, FIG. 2 is a state diagram of temperature rise of a cooling liquid flowing through each block in FIG. 1, and FIG. 3 is an explanatory view of the principle of the present invention. FIG. 4 is a cooling structure diagram of a cold plate showing another embodiment of the present invention, and FIG. 5 is a cooling structure diagram of a conventional cold plate. 11, 12: Multi-chip module, 21, 22: Cold plate, 31, 34: Low temperature coolant inflow block, 32, 33: High temperature coolant inflow block, 4: Piping, 61: Coolant temperature supplied by the cooling device, 62: Cold plate temperature distribution, 63: Left side cooling liquid temperature distribution, 64: Right side cooling liquid temperature distribution, 51: Left side cooling flow, 52: Right side cooling liquid flow, 1A-1D, 2A-2D, 3A-3D , 4A-4D:
Blocks that divide each cold plate, 71-74, 81-8
4,91,92: Blocks respectively.

Front page continuation (72) Inventor Fumiyuki Kobayashi 1 Horiyamashita, Hadano City, Kanagawa Prefecture Kanagawa Plant, Hitachi, Ltd. (56) References JP-A-59-200495 (JP, A) JP-A-61-102799 (JP, A) Actual development Sho 59-58992 (JP, U)

Claims (1)

(57) [Claims] 1. A mounting rack in which a plurality of multi-chip modules having a plurality of heat-generating semiconductors are mounted on a mother board, and a cold plate incorporated in the multi-chip modules and provided with a cooling liquid flow path. In a direct cooling structure of an electronic device, the flow path of the cold plate is divided into a plurality of blocks, each block is provided with a coolant inlet / outlet, and each block is provided with a coolant in a direction opposite to an adjacent block. Cold plate cooling structure characterized by flowing.