JPH03191274A - Cooling device for electronic computer - Google Patents

Abstract

PURPOSE:To provide a high corrosion resistant effect by a method wherein a corrosive ion removing device to selectively remove cation of a corrosive factor is mounted in a circulating route for cooling water containing an inhibitor. CONSTITUTION:Cooling water containing an inhibitor is used for the cooling system for an electronic computer. A control device 11 is connected to an ion analyser or a potential measuring gauge 9. A preinputted reference value is compared with a measuring value of cooling water 1, and when the measuring value exceeds a given value, a flow rate control valve 10 is closed according to a command from a control device 11. Meanwhile, an corrosive ion removing valve 12 is opened to introduce the cooling water 1 to a corrosive ion removing device 13 formed of cation exchange ion or a cation selection exchange film, and corrosive ion in the cooling water 1 is removed. Only an inhibitor component is present in a system water, and corrosion of a system constituting material is effectively suppressed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cooling system for a computer equipped with an IC equipped with a cooling structure, and in particular prevents corrosion of cooling system constituent materials and achieves high corrosion resistance reliability. The present invention relates to a cooling device that obtains properties.

[Conventional technology]

As electronic computers become denser and larger in capacity year by year, the heat generation density of LSIs tends to increase significantly. Conventionally, electronic computers have been cooled using a so-called forced air cooling method in which a fan blows air into the interior, but as the capacity of electronic computers has increased as mentioned above, the amount of heat generated has increased, and air cooling has lowered the temperature below the allowable temperature of LSIs. It is difficult to do so, and liquid cooling is required. For liquid cooling systems, a water cooling method with high cooling efficiency has been proposed, and the most practical and highly efficient method is to provide a cooling structure on the LSI and cool it by passing water through the cooling structure. .

Conventionally proposed liquid cooling systems are disclosed in Japanese Patent Application Laid-open No. 60-160149, Japanese Patent Application Laid-Open No. 60-160150,
As described in each publication of JP-A-52-16981, L
Its main purpose was to efficiently cool heat generating elements such as SI.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, in order to improve the cooling efficiency of LSI, the heat exchanger plate is made thinner, the cooling water is brought as close as possible to directly above the LSI chip, or the in-plane temperature distribution of the LSI chip is made uniform. In order to achieve this, sufficient consideration has been given to the shape of the heat transfer fins provided on the heat transfer plate, the flow path of the cooling water, etc. However, no consideration is given to preventing corrosion of the cooling system as a whole, especially corrosion of the cooling system caused by cooling water.

There was a problem with corrosion resistance reliability.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art described above and to provide a cooling device for an electronic computer with high corrosion reliability.

Here, the circumstances that led to the invention will be explained.

In ultra-large electronic computers, reliability is extremely important as well as performance, and leakage of cooling water due to corrosion of cooling system materials becomes a fatal problem.

However, in order to improve the cooling efficiency of computers, since water is used as a cooling medium, corrosion of metal materials is unavoidable.The cooling system of electronic computers is usually equipped with a purification device consisting of cationic and anionic exchange resin towers. , Conductive dust 1μS/ci or less, dissolved oxygen 100-500pp as cooling water
So-called high-purity water (hereinafter referred to as pure water) that has been adjusted to

On the other hand, the constituent material of the water cooling module is not a single material, but various materials such as Ag-Cu and Sn.
It is configured by being joined with a solder (hereinafter referred to as a joining material) material such as Ag and Au-Sn. According to studies by the present inventors, the corrosion rate of cooling module constituent materials in pure water is greater at the joint between the constituent material and the bonding material than at the constituent material itself.

Even using pure water, local corrosion of the joints could not be prevented.

Therefore, the present inventors considered suppressing local corrosion using an inhibitor.

However, in the above-mentioned cooling system, the inhibitor component is adsorbed on the ion exchange resin tower and does not exhibit a good corrosion inhibiting effect, so a cooling system without a purification device was tested. As a result, if the conductive dust in the liquid becomes high and the absolute amount of inhibitor is insufficient, corrosion of the joint will occur, and trace amounts of eluted metal ions, especially copper ions, will accelerate the corrosion of the iron-based material, which is the main constituent material. I understand.

When using an inhibitor to prevent corrosion, even higher corrosion prevention effects can be obtained by removing only harmful corrosive ions without damaging the inhibitor components.

In order to achieve the above object, a corrosive metal ion removal device for selectively removing only cations of corrosive factors is provided in the cooling water circulation path. Also.

The amount of inhibitor consumption can be determined by monitoring the potential change of a platinum electrode immersed in cooling water, and the amount of inhibitor consumption can also be determined by monitoring the metal ions eluted into the cooling water using an ion analyzer. This is what I did.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a cooling system for an electronic computer having a circulating water cooling module for cooling semiconductor elements mounted on a wiring board, in which corrosive factors are contained in the cooling water circulation path containing an inhibitor. A cooling device for an electronic computer characterized by being provided with a corrosive ion removal device that selectively removes positive ions.

Further, the present invention provides a cooling device for an electronic computer having a circulating water cooling module for cooling semiconductor elements mounted on a wiring board, in which a platinum electrode potential measuring meter and inhibitor addition means are provided in the cooling water circulation path. This cooling device for an electronic computer is characterized in that it includes a control means for regulating the amount of inhibitor added by monitoring the change in potential of a platinum electrode, and a corrosive ion removal device.

The present invention also provides a cooling device for an electronic computer having a circulating water cooling module for cooling semiconductor elements mounted on a wiring board, including an ion analyzer in a cooling water circulation path;
Cooling of an electronic computer, characterized in that it is provided with an inhibitor addition means, a control means for regulating the addition amount of the inhibitor by monitoring specific eluted metal ions, and a corrosive ion removal device. It is a device.

In addition, the present invention provides a cooling device for an electronic computer having a circulating water cooling module for cooling semiconductor elements mounted on a wiring board, in which a platinum electrode potential measuring meter or an ion Install an analyzer,
This computer cooling device is characterized in that the path passing through the corrosive ion removal device is automatically switched by measuring potential changes of a platinum electrode or specific metal ions eluted.

In each of the above devices, the corrosive ion removing device is preferably made of a cation exchange resin that has lower ion selectivity than cations that are corrosive factors, and the corrosive ion removing device is preferably made of an inhibitor. It is also preferable that the resin be made of a cation exchange resin having the same type of ion form as the cation of.

The corrosive ion removal device is preferably made of a cation exchange resin in which the valence of the ions is lower than that of the cations that are the corrosive factor.
Preferably, the inhibitors are of the oxidant type, which are the "form" and the "Li" form.

[Effect]

For example, in the cooling system of an electronic computer, Kovar, nickel, and stainless steel are used as constituent materials, and silver solder is used as a joining member. When these materials undergo corrosion, iron ions are leached from the constituent materials and copper ions are leached from the joining members.

In this process, copper ions precipitate on the iron-based material, and at this time accelerate the corrosion of the iron-based material. According to the present invention, this problem can be solved by removing copper ions, which are corrosive ions, as described above.

Furthermore, the chemical forms of the eluted iron ions, copper ions, etc. change in the high-temperature cooling water, and they float in the cooling water or are deposited in the cooling system as corrosion products such as iron oxide or copper oxide. Among the corrosion products, oxidized steel significantly accelerates the corrosion of ferrous materials.

This problem arises because the source of oxidized steel is copper ions.
According to the present invention, the problem can be solved by removing copper ions as described above.

In the present invention, as a device for removing corrosive ions from the cooling water, a cation exchange resin having lower ion selectivity or lower valence than the cations of the corrosive factor can be used.

For example, using R-Li type resin, Fe"+ and C
When cooling water containing u”+ ions flows, Fe”+ and Cu2
Since + has greater selectivity than Li, the following ion exchange occurs.

As a result, Cu” 10 and Fe” 0 are captured and L instead of 1
emit i inside. In this case, if the cation as an inhibitor is a medium-sized Li inhibitor, the inhibitor component will not be captured by the ion exchange resin, so it will exhibit a good corrosion inhibiting effect. It is preferable that the resin is a cation exchange resin having an ionic form.

Further, similar effects can be obtained with R-Na type resin.

As the inhibitors (corrosion inhibitors) used here, oxidizing agent type inhibitors such as molybdates, nitrates, nitrites, chromates, and tungstates having medium-sized cations of Na+ and Li are preferable. In particular, molybdates exhibit good corrosion inhibiting effects.

These inhibitors inhibit corrosion by oxidizing the surface of the component to form an oxide film.

Furthermore, a cartridge type cation selective exchange membrane may be used as the corrosive ion removal device.

Furthermore, the cooling water circulation system is equipped with a platinum electrode potential measuring meter or ion analyzer and an inhibitor addition system.The former monitors potential changes of the platinum electrode, and the latter monitors specific metal ions eluted. Corrosion resistance reliability can be further improved by creating a system that automatically replenishes the inhibitor into the circulatory system when the measured value exceeds the reference value.

On the other hand, a corrosive ion removal device is installed in parallel in the cooling water circulation system to monitor specific metal ions in the cooling water or the potential of a platinum electrode immersed in the liquid, and if any of the measured values exceeds the standard value. It is also possible to create a system in which the path passing through the corrosive metal ion removal device is automatically switched.

With this system, even if the performance of one of the corrosive ion removal devices deteriorates, the resin and cartridge of the corrosive ion removal device can be replaced without stopping the cooling system.

By combining the above individual effects, corrosive ions generated due to abnormal corrosion of the joint can be removed. That is, by providing the corrosive ion removal system in the cooling system of the computer, a cooling system for the computer with high corrosion reliability is constructed.

[Example] The present inventors conducted the following test in order to experimentally confirm the effect of suppressing local corrosion of joints by using an inhibitor.

Prepare an aqueous solution with a NaCQ concentration of 0.1 + woQ/fl,
To this, various concentrations of molybdate (N a , Mo
○4) was added as an inhibitor to prepare a test solution. Corrosion tests were carried out using Kovar as a constituent material and A as a bonding material.
G-Cu solder is overlapped to form an adhesion gap, and 6
The test was conducted at 0°C for 30 days, and the corrosion rate of Kovar was determined from the maximum crevice corrosion depth. The dependence of the Kovar corrosion rate on the inhibitor concentration at the joint is shown in FIG. 4. As is clear from FIG. 4, the corrosion rate of Kovar decreases as the inhibitor concentration of the test solution increases. Also, from Figure 4, in an aqueous solution of NaCjio, 1mallIQ.

It can be seen that adding an inhibitor of 0.01@oQ/Q or more is particularly effective in suppressing local corrosion.

Examples of electronic computers implementing the present invention are shown in Figures 1 to 3 below.
This will be explained in detail with reference to the drawings.

FIG. 1 shows a case where cooling water containing an inhibitor is used in a cooling system for an electronic computer. FIG. 5 shows a cross-sectional view of a circulating water cooling module for cooling semiconductor elements mounted on a wiring board, that is, a circulating water cooling module for electronic equipment. 21 is a semiconductor chip, 22 is a printed circuit board, 23 is a solder terminal, 24 is a thermally conductive paste, 25 is a cooling plate, 26
is the cap, 27 is the bellows, 28 is the housing, 29
indicates bonding solder. Cooling water flows over the cooling plate 25 along the arrow 30, absorbs heat generated in the semiconductor chip 21, and cools it. That is, in FIG. 1, cooling water 1 is sent by a circulation pump 2 into the circulating water cooling module, which is a cooling part of the electronic equipment 3 of the computer, and is sent to the LS.
By exchanging heat with a heating element such as I, the heating element is cooled, and at the same time, the temperature of the cooling water 1 is raised and the cooling water 1 flows into the cooling water tank 4. A heat exchanger 6 connected to a refrigerator 5 is provided in the cooling water tank 4, and the cooling water 1 heated by cooling the heating element in the computer is passed through the heat exchanger 6. It is then cooled down again. That is, the cooling water tank 4, the refrigerator 5, the heat exchanger 6, and the circulation path for the cooling water 1 form a cooling device.

Next, a portion of the cooling water 1 is connected to an ion analyzer 9 or a potential meter 9 via a cooling water branch valve 7 and a cooling water sampling pipe 8 to detect specific metal ions in the liquid or immerse the liquid in the liquid. Measure the potential of the platinum electrode.

The platinum electrode potential measuring meter 9 measures the potential change of the sample electrode 31 using a potentiostat 32, as shown in FIG.

The ion analyzer detects Fe leaked into the cooling water due to corrosion.
It detects ions such as "CS" and N10.The cooling water 1 discharged from the cooling water tank 4 is normally passed through the flow control valve 10.
The water is then sent to the computer 3 by the pump 2 again. The ion analyzer or potential meter 9 has a control device 11.
is connected, the measured value of the cooling water 1 is compared with the reference value input in advance, and when the value exceeds the predetermined value, the flow rate control valve 10 is closed according to the instructions of the control device 11, and corrosive ions are removed. Open the removal system valve 12 and turn on the cooling water 1.
is introduced into a corrosive ion removing device 13 made of a cation exchange resin or a cation selective exchange membrane, as shown in FIG. 9, to remove corrosive ions in the cooling water 1. The cation exchange resin of the corrosive ion removal device 13 has lower ion selectivity or ion valence than the cations (Cu", Fe", etc.) that are corrosive factors, and has the same type of L as the inhibitor cation. It is better to use a cation exchange resin such as ``, Na 10, etc.'' In other words, by monitoring specific metal ions in the cooling water or the potential of a platinum electrode immersed in the liquid,
The structure is such that when the measured value exceeds a reference value, the system that passes through the corrosive metal ion removal device 13 and the normal system are automatically switched. This is then sent by the pump 2 to the cooling part of the electronic device 3. The cooling water 1 is passed through the corrosive ion removal device 13, and when the potential of the platinum electrode or the value of a specific metal ion becomes below a predetermined value, the corrosive ion removal system is automatically activated again according to instructions from the control device 11. By closing the valve 12 and opening the flow control valve 10, the cooling water 1 passes through a normal cooling system to cool the computer. The relationship between the inhibitor concentration and potential in the control table [11], which defines the amount of inhibitor added by monitoring the potential change of the platinum electrode, is shown in FIGS. 7 and 8. FIG. 7 shows the relationship between the pitting potential of Kovar and the inhibitor concentration, and FIG. 8 shows the relationship between the pitting potential of nickel and the inhibitor concentration. As the amount of inhibitor added increases, the pitting corrosion potential shifts to pitting.

With this system, only inhibitor components are present in the system water, and corrosion of system constituent materials can be effectively inhibited.

FIG. 2 shows a case where an inhibitor addition system is provided in the cooling system. Cooling water 1 circulates within the cooling system as in Fig. 1,
The potential of a specific metal ion in the liquid or a platinum electrode immersed in the liquid is measured by an ion analyzer or a potential meter 9, respectively.

Ion analyzer or potential meter 9 and control device 11
Therefore, if the measured value is higher than a reference value inputted in advance, the inhibitor injection valve 15 is opened in response to an instruction from the control device 11, and the inhibitor is added and replenished into the cooling system. The injected cooling water 1 containing the inhibitor passes through the corrosive ion removal device 13 and thereafter circulates within the cooling system in the same manner as in FIG. When the measured value falls below a predetermined value, the inhibitor injection valve 15 is automatically closed again according to instructions from the control device, and the cooling water 1 passes through the normal cooling system to cool the computer.

This system makes it possible to automatically replenish the inhibitor even when the inhibitor is worn out and corrosion occurs, resulting in a highly effective corrosion protection for the system's constituent materials.

FIG. 3 shows a case where a plurality of corrosive metal ion removal devices are provided in the cooling system. The cooling water 1 circulates within the cooling system in the same way as shown in Fig. 1, and the cooling water 1 that comes out of the cooling water tank 4 is
Normally, the water passes through the corrosive ion removal system valve 12 and is again sent to the computer 3 by the pump 2. The ion analyzer or potential meter 9 has a control device! ! 11 is connected and the measured value is higher than the pre-input reference value, the control device! ! 11, the corrosive ion removal system valve 12 is closed, and the corrosive ion removal system switching valve 16 is opened to switch the cooling water flow path. From then on, the first
It circulates in the system water as shown in the figure.

With this system, the resin or cartridge of the corrosive ion removal device can be replaced without stopping the computer cooling system, making maintenance management easy.

As described above, by installing the corrosive ion removal device of the present invention, only inhibitor components effective for inhibiting corrosion are present in the system water, and a high corrosion inhibiting effect can be obtained.

Note that each of the present embodiments may be used alone, but even if they are combined, the effects will not be affected in any way, and even better effects can be expected.

〔Effect of the invention〕

According to the present invention, it is possible to effectively prevent corrosion of the cooling system of an electronic computer, especially local corrosion of the joints, thereby preventing troubles such as leakage of cooling water.

In addition, by monitoring specific metal ions in the solution or the potential of the platinum electrode immersed in the solution, it is possible to determine the amount of inhibitor consumption and take measures such as replenishing the inhibitor. It can also be prevented.

This has the effect of providing an extremely reliable computer cooling system.

[Brief explanation of drawings]

FIGS. 1 to 3 are system diagrams of computer cooling devices according to different embodiments of the present invention, FIG. 4 is an experimental graph showing the effect of inhibitor concentration on the corrosion rate of Kovar, and FIG. is a cross-sectional view of a cooling module of an electronic device, FIG. 6 is a configuration diagram of a platinum electrode electrometer, FIGS. 7 and 8 are diagrams showing the relationship between potential and inhibitor concentration, respectively, and FIG. 9 is a diagram showing the relationship between potential and inhibitor concentration.
The figure is a sectional view showing one embodiment of a corrosive ion removal device. 1... Cooling water, 2... Circulation pump, 3... Calculator. 4... Cooling water tank, 5... Freezer, 6... Heat exchanger, 7... Branch valve, 8... Sampling pipe,
9... Ion analyzer or potential measuring meter, 10...
Flow rate control valve, 11... Control device, 12... Corrosive ion removal system valve, 13... Corrosive ion removal device, 14... Inhibitor addition device, 15... Inhibitor injection valve, 16. ...Corrosive ion removal system switching valve. Figure 1

Claims (8)

[Claims] 1. In an electronic computer cooling system that has a circulating water cooling module that cools semiconductor elements mounted on a wiring board, a corrosive solution that selectively removes cations of corrosive factors from the cooling water circulation path containing an inhibitor. A cooling device for an electronic computer, characterized by being provided with an ion removal device. 2. In an electronic computer cooling device having a circulating water cooling module for cooling semiconductor elements mounted on a wiring board, a platinum electrode potential measuring meter and an inhibitor adding means are provided in the cooling water circulation path to measure the potential of the platinum electrode. 1. A cooling device for an electronic computer, comprising a control means for regulating the amount of inhibitor added by monitoring changes, and a corrosive ion removal device for selectively removing cations of corrosive factors. 3. In an electronic computer cooling device having a circulating water cooling module for cooling semiconductor elements mounted on a wiring board, an ion analyzer and an inhibitor addition means are installed in the cooling water circulation path to detect specific metal ions eluted. What is claimed is: 1. A cooling device for an electronic computer, comprising a control means for regulating the amount of inhibitor to be added by monitoring, and a corrosive ion removal device for selectively removing cations of corrosive factors. 4. In an electronic computer cooling system that has a circulating water cooling module that cools semiconductor elements mounted on a wiring board, a platinum electrode potential measuring meter or ion analyzer is installed in the cooling water circulation path containing the inhibitor. An electronic device characterized in that a path passing through a corrosive ion removal device that selectively removes cations of corrosive factors is automatically switched by measuring changes in electrode potential or specific metal ions eluted. Computer cooling system. 5. 5. A cooling device for an electronic computer according to claim 1, wherein the corrosive ion removal device is made of a cation exchange resin that has less ion selectivity than cations that are corrosive factors. 6. 5. A cooling device for an electronic computer according to claim 1, wherein the corrosive ion removal device is made of a cation exchange resin having the same type of ion type as the inhibitor cation. 7. 5. A cooling device for an electronic computer according to claim 1, wherein the corrosive ion removal device is made of a cation exchange resin in which ions have a lower valence than cations that are corrosive factors. 8. 5. A cooling device for an electronic computer according to claim 1, wherein the inhibitor is an oxidizing agent type inhibitor in which the cations are Na^+ type and Li^+ type.