JPS639399B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to modification of the mounting structure of integrated circuits or high-density integrated circuits used in large-scale electronic computers and the like.

[Conventional technology]

Conventionally, in the mounting structure of these integrated circuits, as shown in FIG. 1, a large number of integrated circuits 2 are arranged on a printed wiring board 1 in an array like a board pattern. FIG. 1 shows a case where integrated circuits 2 are arranged in four columns. This type of integrated circuit is generally cooled by forcing air between the printed wiring boards 1 using a blower (not shown) to cool the integrated circuit 2.

[Problem that the invention seeks to solve]

However, in such a mounting structure, a portion of the cooling air passes between the rows of integrated circuits without contributing to the cooling of the integrated circuits, so almost all of the cooling air is used to cool the integrated circuits. It has the disadvantage that it cannot be used for It would be possible to eliminate the narrow spaces between the rows of integrated circuits, but since there is a limit to the density of wiring on printed wiring boards, it is necessary to leave some spacing between them. Furthermore, since the areas between the integrated circuits in the same row arranged parallel to the cooling fluid flow direction form depressions with respect to the cooling flow, the cooling effect in these areas is poor. If the array pitch of integrated circuits is increased,
Although cooling is improved, the disadvantage is that the wiring distance between integrated circuits becomes longer, which slows down the signal transmission speed.

There is also a method of flowing cooling air perpendicularly to the integrated circuit as described in Japanese Patent Laid-Open No. 53-107666, but even this method has the same problems as described above.

In order to improve the drawbacks of the mounting structure shown in Figure 1, the second
The implementation structure shown in the figure is known. That is, a large number of integrated circuits 2 are arranged on a printed wiring board 1 in a staggered manner. However, although the mounting structure shown in Figure 2 improves the effective use efficiency of cooling air,
Compared to the mounting structure shown in the figure, there is a drawback that the printed wiring board 1 becomes larger due to the staggered shift of the integrated circuits 2. In order to increase the efficiency of using the area of the printed wiring board 1, it is sufficient to manufacture an integrated circuit structure with left and right sides reversed, but there are problems such as complication of integrated circuit mounting wiring and increased manufacturing cost.

An object of the present invention is to obtain an integrated circuit mounting structure that can improve the cooling effect of a large number of integrated circuits arranged on a wiring board.

[Means for solving problems]

In order to achieve the above object, the present invention comprises a wiring board, in which a plurality of integrated circuits are arranged in a row with gaps between them, and a restricted space through which a cooling fluid flows is formed on the upper surface of the integrated circuits. arranging the wiring board, and arranging the integrated circuits in each row on the board so as to be shifted in a direction intersecting the flow direction of the cooling fluid within a range not exceeding the width of adjacent integrated circuits in the same row, Integrated circuits in adjacent rows in the flow direction do not overlap, and spaces through which the cooling fluid passes are provided on both sides of each row of integrated circuits.

[Effect]

According to the present invention, the integrated circuits protrude with respect to the flow direction of the cooling fluid on both sides of each row of integrated circuits, and the upstream portion near the protruding side of the integrated circuits that protrude to one side with respect to the flow of the cooling fluid , the flows of the cooling fluid collide with each other and the pressure of the fluid becomes high, and the flow of the cooling fluid separates at the downstream part near the protruding side and the pressure of the fluid becomes low. Similarly, a similar pressure change occurs near the protruding side of the integrated circuit protruding to the other side.
As a result, the above-mentioned pressure rise and pressure drop occur at both left and right ends of the space between a pair of integrated circuits protruding left and right, and this pressure difference causes the space between the integrated circuits in each row to be An induced flow can be generated in a direction transverse to the flow of the cooling fluid.

In addition, the induced flow generated in the space between the integrated circuits in each row and flowing laterally, the flow of the cooling fluid flowing in the restricted space formed on the upper surface of the integrated circuit arranged on the substrate, and the The flow of cooling fluid flowing through the cooling fluid penetration spaces formed on both sides of the column merges with each other, so that the flow direction of the cooling fluid extends over the entire height of the flow path on the side of the integrated circuit, and the flow direction of the cooling fluid flows on the side of the integrated circuit. It is possible to generate a vertical vortex that rotates toward the direction. The integrated circuit is cooled by this longitudinal vortex and the induced flow.

〔Example〕

An embodiment of the integrated circuit mounting structure of the present invention will be described below with reference to FIGS. 3 and 4.

In the figures, the same reference numerals as in FIGS. 1 and 2 indicate the same parts or equivalents. Printed wiring board 1
Above, a large number of integrated circuits 2 are arranged in rows (two rows in the embodiment shown in FIG. 3) with gaps in the flow direction 3 of the cooling fluid, and on both sides of each row there are straight lines through which the cooling fluid passes. It is attached so as to leave a space 9.
Further, the wiring boards 1, 1' are arranged so that a narrow restricted space 7 through which cooling fluid flows is formed between the upper surface 21 of the integrated circuit 2 and the wiring board 1' above it. Additionally, each column of integrated circuits 2
are arranged in a direction perpendicular to the flow direction 3 of the cooling fluid, alternately shifted left and right within a range not exceeding the width of the integrated circuit 2.
It goes without saying that a space 7 is also provided between the upper surface of the outermost wiring board 1 and the body to which this wiring board is attached.

With the above configuration, every other integrated circuit 2 protrudes alternately on the left and right with respect to the flow direction 3 of the cooling fluid on both sides of each row of integrated circuits. Therefore, at the upstream portion 8a near the side 2a of the integrated circuit 2 protruding toward the space 9, the flow of the cooling fluid collides with the integrated circuit 2, increasing the pressure of the fluid. Further, on the downstream side 8b near the protruding side 2a of the integrated circuit 2, the flow of the cooling fluid separates and the pressure of the fluid becomes low. As a result, the pressure rise and pressure drop occur at both left and right ends of the space 8 between the adjacent integrated circuits 2, 2 in the same row that protrude left and right, that is, at the portions 8a and 8b. This pressure difference induces a flow 4 in the space 8 as shown by the arrow. Since this induced flow 4 is arranged so that every other integrated circuit 2 is shifted alternately left and right, the flow direction of this induced flow 4 is opposite to the left direction and the right direction for every other integrated circuit.

Furthermore, three flows, the induced flow 4, the flow 3a flowing through the space 7 formed on the top surface of the integrated circuit 2, and the flow 3b flowing through the penetrating space 9 formed on the side surface 22 of the integrated circuit 2, merge with each other. As a result, a longitudinal vortex 5 is generated that extends over the entire height of the flow path of the wiring board 1 and moves along the sides of the integrated circuit while swirling in the direction 3 of the flow of the cooling fluid. The direction of the vertical vortex 5 is determined by the flow direction of the induced flow 4, and the direction of the vortex is opposite to that of every other integrated circuit and is induced alternately on the left and right.

As a result, the integrated circuit 2 is effectively cooled by the induced flow 4 and the longitudinal vortex 5.

Figure 5 shows that 10 integrated circuits are arranged in two rows, and the shift distance δ of the integrated circuits is calculated using the integrated circuit width l (=20 mm square).
On the other hand, we investigated the degree of uniformity of air temperature when each integrated circuit generated a constant 2W of heat and flowed a wind of 7m/s using four types: 0, 1/4, 1/2, and 1. It is something. The vertical axis shows the ratio of the difference between the maximum temperature Tmax and the average temperature Tavg to the average temperature Tavg of the outlet air temperature, and the smaller this value is, the more uniform the air is. In FIG. 5, when δ/l=0, the array is two-column, and when δ/l=1, the array is staggered. Fifth
As shown in the figure, even if the shift distance δ is about half, the degree of air temperature rise is almost the same as in the staggered arrangement. Fifth
Although the figure merely shows the state of the air temperature distribution, the induced flow 4 and longitudinal vortex 5 improve the heat transfer coefficient of the integrated circuit, so that the integrated circuit can be cooled more effectively.

Other embodiments of the invention are shown in FIGS. 6-8.

FIG. 6 differs from the embodiment in FIG. 3 in that the directions in which adjacent integrated circuit rows are shifted are opposite to each other. In addition, in the embodiment of FIG. 7, one integrated circuit 2 is installed every second, and in the embodiment of FIG. 8, two integrated circuits 2 are installed every second, each not exceeding the width of the integrated circuit. This shows the case where the cooling fluid is shifted in the direction perpendicular to the flow direction of the cooling fluid.
The number of integrated circuits to be shifted can be arbitrarily selected within a range that does not become too large. Even in the case of these other embodiments, the same functions and effects as those of the above-mentioned embodiment can be obtained. Further, in the above embodiment, the case where one integrated circuit constituting each column is provided singly is shown, but the same applies even if a plurality of integrated circuits constituting each column are arranged closely and forming a pair. There is an effect.

Further, in the above embodiments, the integrated circuits are shifted symmetrically and have the same size, but they do not necessarily have to be the same size. However, the effect is greatest when they are arranged with the same dimensions. It should be noted that, of course, the mounting structure of the present invention can be applied to the entire integrated circuit arranged on a wiring board, but it is also possible to apply the present invention only to an area where temperature rise near the outlet of the cooling fluid is a problem. good.

〔Effect of the invention〕

According to the present invention, an induced flow, that is, a flow of cooling fluid, can be generated in the space between the integrated circuits in each row, and each integrated circuit can be cooled by this induced flow. Moreover, according to the present invention, the induced flow, the flow of the cooling fluid flowing in the upper surface space of the integrated circuit, and the flow of the cooling fluid flowing in the spaces on both sides of the integrated circuits in each row merge with each other. Since it is possible to generate a longitudinal vortex that extends over the entire height of the flow path on the side part and that moves while swirling along the side part of the integrated circuit in the flow direction of the cooling fluid, this longitudinal vortex and the induced flow create an integrated circuit. This has the effect of greatly improving the cooling effect of the circuit.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating an example of a conventional integrated circuit mounting structure, FIG. 2 is a front view of a printed wiring board showing another example of a conventional integrated circuit mounting structure, and FIG. 3 is a perspective view illustrating an example of a conventional integrated circuit mounting structure. A front view for explaining one embodiment of an integrated circuit mounting structure, FIG. 4 is the same as in FIG. 3.
5 is a characteristic diagram illustrating the cooling effect of the mounting structure of FIG. 3, and FIGS. 6, 7, and 8 are front views illustrating other embodiments of the present invention, respectively. It is. DESCRIPTION OF SYMBOLS 1, 1'...Wiring board, 2...Integrated circuit, 21...Top surface of integrated circuit, 22...Side surface of integrated circuit, 2a...Protruding side of integrated circuit, 3...Flow direction of cooling fluid, 3a
...Flow on the top surface of the integrated circuit, 3b...Flow on the side of the integrated circuit, 4...Induced flow, 5...Longitudinal vortex, 7...Restricted space formed on the top surface of the integrated circuit, 8a...Protrusion of the integrated circuit Upstream portion near the side, 8b... Downstream portion near the protruding side of the integrated circuit, 9... Penetrating space formed on both sides of the integrated circuit in each row.

Claims (1)

[Claims] 1 A plurality of integrated circuits are arranged in a row on a wiring board with gaps between them, the wiring board is arranged so that a restricted space through which a cooling fluid flows is formed on the upper surface of the integrated circuit, and On the substrate, the integrated circuits in each row are staggered in a direction intersecting the flow direction of the cooling fluid within a range that does not exceed the width of the adjacent integrated circuits in the same row, and An integrated circuit mounting structure characterized in that integrated circuits do not overlap and spaces are provided on both sides of each row of integrated circuits for cooling fluid to pass through.