JPH0783078B2 - Semiconductor cooling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention allows a flexible cooling channel to be in contact with a heating element of an electronic component typified by a semiconductor element and the like, and cooling water can be introduced into the cooling channel. The present invention relates to a semiconductor cooling device that cools a heating element by flowing it.

[Conventional technology]

In the conventional device, as described in, for example, Japanese Patent Laid-Open No. 61-32449, a cooling fin is attached to the back surface of a heating element (for example, a semiconductor chip), and cooling water is supplied to cool the heating element. Generally, a plurality of heating elements are arranged on the board, and the wiring inside the chip and the wiring inside the board are connected by a flip chip system (solder ball) to exchange signals. On the other hand, on the back side of the heating element chip, a flexible structure such as a bellows constitutes the inlet and outlet passages of the cooling water, and the flexible structure is metallically joined by a cooling water header and an O-ring or by soldering. There is. The inlet and outlet passages for the cooling water may be provided separately for one chip, or may have a double pipe structure. In any case, such a flexible structure minimizes the direct influence of the stress due to the displacement of the cooling water header on the chip. Cooling water flowing through the flexible structure cools the heating element chip through the cooling fins.
There are cases where metal connection is made by soldering or the like, and cases where good thermal conductivity such as silicone oil or grease is inserted. In any case, this part has taken measures to improve the heat transfer.

[Problems to be Solved by the Invention]

Since the area of the heating element chip to be cooled is small in the cooling structure to which the present invention is applied, the refrigerant liquid typified by water or the like has to flow in a very small space. Due to the small space, uneven flow of the refrigerant liquid is likely to occur. When uneven flow occurs, the flow velocity of the refrigerant liquid flowing inside the fins on the back surface of the chip will be locally different depending on the place, so that the cooling performance distribution on the surface of the chip occurs and the chips are arranged in high density inside the chip. Since the junction temperature of the semiconductor element is significantly different, it not only adversely affects the electrical operating characteristics of the semiconductor, but also the temperature distribution in the chip becomes large. The warp of the chip is likely to be large, and also from the viewpoint of mechanical strength, damage to the chip, damage to the solder balls of the flip flop, and the like are likely to occur.

Therefore, in the prior art, a space is provided near the inlet and outlet of the refrigerant liquid so that the refrigerant liquid can flow uniformly between the cooling fins. However, in this case, although the cooling performance of the fin portion is high, in the space portion near the inlet and outlet of the refrigerant liquid, the flow velocity of the refrigerant liquid becomes slow and the cooling performance deteriorates. In other words, there is a distribution of cooling performance on the back surface of the chip,
This causes problems such as a large difference in temperature, thermal stress, and chip warpage.

Further, in JP-A-61-32449, a cooling liquid distribution means is provided, but there are two cooling liquid inflow passages and two outflow passages.
It is composed of a heavy pipe structure. Therefore, the coolant liquid that has flowed in through the bellows at the center is distributed on the center line to the center of the integrated circuit chip by the cooling liquid distribution means, and once on both end faces of the chip, for example, in the groove. It cools the cooling plate by passing through the attached cooling plate (having the same function as the fin row). Then, it flows out from both ends of the chip through the space between the double bellows. Therefore, the refrigerant liquid that has reached the back surface of the chip through the inner bellows is divided into two parts on the chip center line and flows inside the grooved cooling plate on the back surface of the chip. That is, when the flow rate is the same, the refrigerant liquid is divided into two, the flow velocity is halved and the cooling performance is reduced as compared with the case where the flow rate is not divided into two. When the cooling performance deteriorates, the temperature of the semiconductor element junction in the chip rises, the element is easily damaged, and the life of the element is shortened.
Further, if the flow rate is doubled in order to make the cooling performance equal to that when the refrigerant liquid is not divided into two, the amount of water used is doubled and the pump power for circulating the refrigerant liquid is increased economically. Cause loss.

The object of the present invention is to solve the above-mentioned problems of the prior art, so that the refrigerant liquid introduced to the back surface of the chip is evenly distributed without lowering the flow velocity, and moreover, to flow evenly over the entire back surface of the chip. To do.

[Means for Solving the Problems]

In order to achieve the above object, the semiconductor cooling device of the present invention,
A cooling structure with one end of two flexible bellows attached is joined to each heating element chip arranged on the substrate, and the other ends of the two flexible bellows are attached to the refrigerant liquid header. Cooling the heating element chip by allowing the refrigerant liquid to flow from the bellows side into the cooling structure and from the other one bellows side so that the refrigerant liquid flows out from the cooling structure. In the device, a grooved plate having parallel groove rows is mounted on the heating element chip surface, and a length reaching the full width of the groove rows in a direction orthogonal to the groove rows on the bellows sides at both ends of the groove row. Place the slit of
A refrigerant liquid diffusion chamber is provided between the slit and the bellows, and a partition is provided along one diagonal line of the frame-shaped plate.

Also, a cooling structure to which one end side of two flexible bellows is attached is joined to each heating element chip arranged in plural on the substrate, and the other end of the two flexible bellows is attached to the cooling liquid header, Refrigerant liquid flows into the cooling structure from one bellows side, and refrigerant liquid flows out from the cooling structure from the other one bellows side. In the device for cooling the heating element chip, a grooved plate having parallel groove rows is attached to the heating element chip surface, and the bellows side of both ends of the groove row is orthogonal to the groove row in the entire width of the groove row. Arrange a slit of a length to reach, the slit has a narrow slit width on the side where the bellows is attached, and widens the slit width as it goes away from the side where the bellows is attached,
A refrigerant liquid diffusion chamber is provided between the slit and the bellows.

Further, a cooling structure having one end side of two flexible bellows attached thereto is joined to each heating element chip arranged on a plurality of substrates, and the other ends of the two flexible bellows are attached to a refrigerant liquid header, Refrigerant liquid flows into the cooling structure from one bellows side, and refrigerant liquid flows out from the cooling structure from the other one bellows side. In the device for cooling the heating element chip, a grooved plate having parallel groove rows is attached to the heating element chip surface, and the bellows side of both ends of the groove row is orthogonal to the groove row in the entire width of the groove row. Arrange a slit of a length to reach, provide a refrigerant liquid diffusion chamber between the slit and the bellows, in the vicinity of the bellows outlet in the refrigerant liquid diffusion chamber,
It is characterized in that a straightening vane is provided.

[Action]

A plurality of chip heating elements are arranged on the substrate. A wiring layer is inserted in the substrate, and both are electrically connected by a solder ball having an outer diameter of about 1 mm or less. Since the semiconductor element generates heat during operation, unless it is cooled, the element may be damaged. The chip cooling means is provided with two flexible flow channel structures composed of bellows or the like on the back surface side of the chip. One end of the flexible flow path structure is fixed to the cooling water header, and the other end is fixed to the back surface of the heating element chip via the cooling fin. Refrigerant liquid typified by water flows from the cooling water header into one flexible flow path structure, flows through the cooling fins, cools the heating element chip through the cooling fins, and is cooled by another flexible flow structure. Passes through the road structure and returns to the cooling water header. In terms of temperature, since the chip portion of the heating element is heated, the temperature becomes relatively high, and the cooling water header side through which the cooling water flows becomes relatively low temperature. Due to this temperature difference, in the cooling device assembled at room temperature, the substrate relatively expands and the cooling water header contracts. In operation, even if thermal stress acts on the cooling water header and the substrate due to the temperature difference between them, the spring action of the bellows can reduce the stress applied to the chip heating element.

Next, how the refrigerant liquid flows will be described.

First, the cooling water (refrigerant liquid) flows into one flexible bellows attached to the cooling water header. Subsequently, the bellows are guided to a refrigerant liquid diffusion chamber provided on the refrigerant liquid outlet side. The refrigerant liquid flowing in the bellows in the direction perpendicular to the chip surface is spread to the chip surface side in the refrigerant liquid diffusion chamber.

As described above, since the refrigerant liquid diffusion chamber is divided into two parts by dividing the refrigerant liquid diffusion chamber along one diagonal line of the frame-shaped plate, the inflowing refrigerant liquid does not mix with the returning refrigerant liquid heated by the heating element chip. , It is possible to always supply a fresh refrigerant liquid to the chip surface side. Further, by providing the straightening plate near the bellows outlet of the refrigerant liquid diffusion chamber, it is possible to spread the flow of the refrigerant liquid to a position far from the vicinity of the outlet.

Further, next to the refrigerant liquid diffusion chamber, a slit, which is a refrigerant liquid rectifying groove, is provided so as to substantially extend along one side of the rectangular chip, so that the refrigerant liquid spreads substantially uniformly over this one side.

As described above, this slit has a narrow slit width on the side on which the bellows where the refrigerant liquid easily flows is attached, and the refrigerant liquid becomes difficult to flow as it goes away, so by increasing the slit width, the length of the slit becomes longer. A more uniform flow can be created in the direction.

Since the cooling fin array provided between the slit and the chip is configured to run in a direction substantially orthogonal to this one side, the refrigerant liquid that spreads uniformly in the slits is cooled by each cooling fin. They flow in a row of grooves between them at a substantially equal flow rate and are guided to one side of the chip opposite to the inflow side.

When flowing through the groove array between the cooling fins, the refrigerant liquid receives the heat of the heating element chips via the cooling fins, cools the heating element chips, and the refrigerant liquid itself is heated. The heated refrigerant liquid then returns to the cooling water header side, following a system path that is completely opposite to the case at the time of inflow. That is, the refrigerant liquid that has reached the one side of the chip at the other end is a slit provided on the outlet side,
Then, it passes through the refrigerant liquid diffusion chamber, the bellows on the outlet side, and returns to the cooling water head side.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. A cooling structure is arranged on the back surface side of the heating element chip (not shown), and the cooling structure 1 and the heating element chip are soldered together.
Alternatively, heat conductive grease and silicone oil are used for joining. FIG. 1 is an exploded view of the cooling structure 1. From the heating element chip side, cooling plate 2, groove array plate 3, slit plate 4, refrigerant liquid diffusion plate 5,
It consists of an upper lid 6 and a flexible channel, for example a bellows 7. Two bellows are required for one heating element chip because they constitute the inlet and outlet of the refrigerant liquid. Cooling plate 2
Is for preventing contact between the refrigerant liquid and the heating element chip. Therefore, it has the same shape as the heating element chip. For example, if the heating element chip has a rectangular shape, the cooling plate 2 also has a rectangular shape. Since the shape of the heating element chip is generally rectangular,
In the following, the figure shows the case of a rectangular shape. In some cases, the size of the cooling plate 2 is equal to that of the heating element chip, or the cooling plate 2 is slightly larger in order to improve the cooling efficiency. The cooling plate 2 may be omitted if the refrigerant liquid and the heating element chip can contact each other. The outer shape and size of the grooved plate 3 are the same as those of the cooling plate 2. Therefore, the outer shape becomes rectangular. When the cooling plate 2 is not provided, the size of the groove array plate 3 is almost the same as that of the heating element chip.

The grooved plate 3 has a number of equal, narrow grooves 8 running in parallel. The direction of the groove 8 is substantially parallel to the two opposite sides 10 of the rectangular shape of the groove array plate 3 and substantially perpendicular to the other two opposite sides 11. Since the coolant liquid flows in the grooves 8, the rectangular cross section between the grooves serves as the cooling fins 9, respectively. The outer shape and size of the slit plate 4 are substantially the same as those of the groove row plate 3. Therefore, the outer shape is generally rectangular. Slit
Two 12 are provided and run substantially parallel to the two opposite sides 13 and substantially perpendicular to the other two opposite sides 14. The width of the slit 12 is equal to its longitudinal direction. The position of the slit 12 is near the two sides 13 that are substantially parallel to the slit 12. The external shape and size of the refrigerant liquid diffusion plate 5 are almost the same as those of the groove array plate 3. Therefore, it is generally rectangular.
As shown in the figure, the refrigerant liquid diffusion plate 5 is in the form of a frame, and a partition 15 is provided along the diagonal line of the frame so as to divide the inside of the frame into two parts. Therefore, two refrigerant liquid diffusion chambers 16 are provided inside the frame. The outer shape and size of the upper lid 6 are substantially the same as those of the groove row plate 3.
Therefore, it is generally rectangular. The upper lid 6 has two openings 17. The position of the opening 17 is, as shown in the figure, on the side of the corner 18 that is opposed to the rectangular shape. The size of the opening 17 is such that the bellows 7 can be inserted and there is a gap in which the upper lid 6 and the bellows 7 can be joined. Therefore, the clearance between the outer diameter of the insertion portion of the bellows 7 and the inner diameter of the opening 17 is approximately
It is better to be about 10 to 100 μm. The shape of bellows 7 is
The cross section shall be circular.

In the cooling structure 1, a cooling plate 2, a groove array plate 3, a slit plate 4, a refrigerant liquid diffusion plate 5, and an upper lid 6 are laminated and joined as shown in the figure. Then, the bellows 7 is inserted into the opening 17 of the upper lid 6 and joined by brazing, for example. The relative positional relationship between the components 2 to 6 is as shown in FIG. That is, the groove 8 of the groove array plate 3,
The slits 12 of the slit plate 4 are in the orthogonal direction. The positional relationship between the cooling liquid diffusion plate 5 and the upper lid 6 is such that the upper lid 6 is placed on the corner side of the rectangular refrigerant liquid diffusion plate 5 where the partition 15 is not provided.
It is arranged so that the opening 17 provided in the. That is, the opening 17 'is arranged on the side of the refrigerant liquid diffusion chamber 16' having a large area.

The external appearance at the time when the components 2 to 7 are joined is shown in FIG.
A sectional view taken along the line AA of the central portion of FIG. 2 is shown in FIG. The surface of the cooling plate 2 of the cooling structure 1 shown in FIG. 2 and, for example, a heating element chip (not shown) are joined by soldering or the like. And the bellows 7 is connected to a refrigerant liquid header (not shown).
The heating element chip is cooled via the cooling plate 2 by flowing a coolant liquid as shown by an arrow in FIG. 3 (described later).
Therefore, the cooling plate 2 and the groove array plate 3 are made of a material having good thermal conductivity,
For example, Cu, SiC, AlN, etc. The slit plate 4, the refrigerant liquid diffusion plate 5, and the upper lid 6 are made of materials having excellent corrosion resistance. For example, SUS, KO, Ti, etc. The bellows 7 is also a material having excellent corrosion resistance, such as Ni, Ti and KO.

Next, the flow condition of the refrigerant liquid will be described with reference to FIG. The refrigerant liquid flowing from the refrigerant liquid header into the bellows 7'passes through the bellows 7'and then flows into the refrigerant liquid diffusion chamber 16 '. Since the area of the refrigerant liquid diffusion chamber 16 'is wider than that of the opening 17', the refrigerant liquid is spread as shown by the arrow in FIG.
In particular, it spreads in the front direction (not shown) perpendicular to the paper surface in the refrigerant liquid diffusion chamber 16 '. In other words, it spreads in the direction in which the slit 12 'is running. Therefore, subsequently, the refrigerant liquid uniformly flows in the longitudinal direction of the slit 12 ′ and is guided into the groove 8. While flowing in the groove 8, the cooling fins 9 and the cooling plate 2 are cooled, and the refrigerant liquid itself is heated. The refrigerant liquid flowing in the groove 8 reaches the other end of the groove, and the slit 12 and the refrigerant liquid diffusion chamber 16
To flow to the bellows 7 and return to the refrigerant liquid header.

As described above, since the refrigerant liquid sufficiently spreads in the refrigerant liquid diffusion chamber 16 ', the flow velocity of the refrigerant liquid flowing into the slit 12' is evenly distributed in the longitudinal direction of the slit, resulting in a uniform flow and the groove. You are led to row 8. Since the grooves 8 are provided on both end sides sufficiently long, the flow in the grooves 8 is a uniform flow with respect to each groove, and flows in almost the entire area of the cooling plate 2 and passes through the cooling fins 9. The cooling plate 2 directly or directly. That is, since the flow of the refrigerant liquid on the cooling plate 2 is uniform over the entire area, the cooling performance is substantially uniform over the entire area, and it is possible to cool the wide area of the cooling plate.

Next, another embodiment will be described. FIG. 4 shows the slit width of the slit plate 4 changed in the longitudinal direction. That is, as described above, the refrigerant liquid diffusion chamber 16 'functions to make the flow out of the nozzle 7'uniform in the longitudinal direction of the slit 12'. Therefore, as shown in FIG. 4, the slit width on the side where the nozzle 7'is provided is narrowed, and the slit width is widened on the side where the refrigerant liquid spreads. In this way, even if the refrigerant liquid diffusion plate 5 is not provided, the slits 12 'serve to form the grooves 8
It is possible to make the internal flow uniform. That is, since the refrigerant liquid easily flows into the slit 12 'near the outlet of the nozzle 7', the slit width is narrowed to provide flow resistance. On the contrary, by moving away from the outlet of the nozzle 7 ',
Since the refrigerant liquid will not flow easily, widen the slit width,
Make it easy to flow. In this way, a uniform flow can be created in the longitudinal direction of the slit 12 '. FIG. 5 is an external view of the cooling structure 1 using the slit plate 4 of FIG. In this case, the refrigerant liquid diffusion plate 5 can be omitted. Of course, it is obvious that in the cooling structure using the slit plate 4 and the refrigerant liquid diffusion plate 5 shown in FIG. 4, the flow of the refrigerant liquid in each groove 8 can be made even more uniform.

FIG. 6 shows another embodiment. A current plate 19 is provided near the nozzle outlet of the refrigerant liquid diffusion chamber. It is advisable that the flow regulating plate 19 be located at the lower end of the nozzle outlet, and protrude from the side 20 that constitutes the forehead, for example, as shown in FIG. 6, into the corner on the side that presents a substantially right angle to the refrigerant liquid diffusion chamber. The current plate 19 may have a shape obtained by cutting a circle into quarters as shown in FIG. 6, for example. 7th
The figure shows a cross section of the cooling structure in the case of using the refrigerant liquid diffusion plate 5 with the current plate 19 shown in FIG. 6, and the arrow 20 shows the flow of the refrigerant liquid. That is, as described above, since the flow rate of the refrigerant liquid flowing out from the nozzle 7'is high, the refrigerant liquid easily flows into the slit 12 'near the outlet. Therefore,
If a current plate 19 is provided in the refrigerant liquid diffusion chamber near the outlet,
The refrigerant liquid flowing out from the nozzle 7'is bent by the straightening plate 19 as shown by an arrow 20 in FIG. 7, and the flow spreads from the vicinity of the outlet of the nozzle 7'to the slit at a position distant therefrom. Then, it is prevented from easily flowing into the slit near the refrigerant liquid outlet of the nozzle. The inflow velocity of the refrigerant liquid can be made substantially uniform over the entire length of the slit 12 'in the longitudinal direction. Of course, the refrigerant liquid diffusion plate shown in FIG.
It is apparent that the cooling structure shown in the figure, which also uses a slit plate in which the width of the slit is changed in the longitudinal direction, makes the flow of the refrigerant liquid in each groove 8 more uniform.

〔The invention's effect〕

According to the present invention, it is possible to provide a mechanism that makes the flow of the refrigerant liquid uniform and guides it onto the cooling plate on the side opposite to the heating element chip, that is, on the nozzle side with respect to the cooling plate 2 and the groove array plate 3. Because of this, the groove 8 of the groove array plate 3 can be made sufficiently long. As a result, a uniform flow can be obtained for each groove row, and the groove rows can be provided in a wide range, so that it is possible to obtain uniform cooling performance over a wide range of cooling plate regions. Thereby, the temperature distribution of the heating element chip can be made uniform, and the temperature of many semiconductor element junctions in the heating element chip can be made uniform, so that the warpage of the chip can be suppressed to a minimum, and the wiring inside the chip can be It is possible to extend the life of the solder balls that connect the wirings in the substrate, and the strength is excellent.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an embodiment of the present invention, and FIG.
Fig. 3 is an external view of the drawing, Fig. 3 is a sectional view taken along the line A-A in Fig. 2, Fig. 4 is a perspective view showing another embodiment of the present invention, Fig. 5 is an external view of another embodiment, and Fig. 6 Is a perspective view showing another embodiment of the present invention,
FIG. 7 is a sectional view showing another embodiment of the present invention. 1 ... Cooling structure, 2 ... Cooling plate, 3 ... Groove row plate, 4 ...
… Slit plate, 5 …… Refrigerant liquid diffusion plate, 6 …… Upper lid, 7,
7 '... Bellows, 8 ... Groove, 9 ... Cooling fin, 12,1
2 '... Slit, 16, 16' ... Refrigerant liquid diffusion chamber, 19 ... Rectifier plate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Motohiro Sato 502 Jinritsucho, Tsuchiura-shi, Ibaraki Hiritsu Manufacturing Co., Ltd.Mechanical Research Institute (72) Toshihiro Yamada 502 Jinritsu-cho, Tsuchiura-shi, Ibaraki Hiritsu Co., Ltd. Machinery Research Laboratory, Manufacturing Co., Ltd. (56) Reference JP-A-61-32449 (JP, A)

Claims (4)

[Claims] 1. A cooling structure to which one end side of two flexible bellows is attached is joined to each heating element chip arranged on a substrate, and the other end of the two flexible bellows is a refrigerant liquid header. Attached, the refrigerant liquid flows into the cooling structure from one bellows side, from the other one bellows side, so that the refrigerant liquid flows out of the cooling structure, by flowing the refrigerant liquid into the cooling structure, A device for cooling a heating element chip, wherein a grooved plate having parallel groove rows is mounted on the heating element chip surface, and the groove rows are arranged on both sides of the groove row in a direction orthogonal to the groove row. Arrange a slit of a length that reaches the full width of, between the slit and the bellows,
A semiconductor cooling device comprising: a refrigerant liquid diffusion chamber configured by partitioning along one diagonal line of a frame-shaped plate. 2. A cooling structure to which one end side of two flexible bellows is attached is joined to each heating element chip arranged on a substrate, and the other end of the two flexible bellows is a refrigerant liquid header. Attached, the refrigerant liquid flows into the cooling structure from one bellows side, from the other one bellows side, so that the refrigerant liquid flows out of the cooling structure, by flowing the refrigerant liquid into the cooling structure, A device for cooling a heating element chip, wherein a grooved plate having parallel groove rows is mounted on the heating element chip surface, and the bellows grooves at both ends of the groove row are arranged in a direction perpendicular to the groove row. A slit having a length that reaches the full width of the bellows is arranged, and the slit has a narrow slit width on the side on which the bellows is attached, and widens the slit as it goes away from the side on which the bellows is attached. The semiconductor cooling device is characterized by providing a refrigerant liquid diffusion chamber between said bellows and. 3. A cooling structure, to which one end side of two flexible bellows is attached, is joined to each heating element chip arranged on the substrate, and the other end of the two flexible bellows is a refrigerant liquid header. Attached, the refrigerant liquid flows into the cooling structure from one bellows side, from the other one bellows side, so that the refrigerant liquid flows out of the cooling structure, by flowing the refrigerant liquid into the cooling structure, A device for cooling a heating element chip, wherein a grooved plate having parallel groove rows is mounted on the heating element chip surface, and the groove rows are arranged on both sides of the groove row in a direction orthogonal to the groove row. A slit having a length that reaches the full width of the semiconductor device, a refrigerant liquid diffusion chamber is provided between the slit and the bellows, and a rectifying plate is provided near the bellows outlet in the refrigerant liquid diffusion chamber. Cooling system. 4. The semiconductor cooling device according to any one of claims 1 to 3, wherein a cooling plate, a grooved plate, a slit plate, and a refrigerant liquid diffusion plate are arranged from the side of the heating element chip. A semiconductor cooling device, wherein upper lids are laminated and joined, and the bellows is joined to an opening of the upper lid.