Cooling device

Abstract

To provide a cooling device 100 capable of blocking thermal neutrons emitted to a semiconductor substrate 3 immersed in a coolant 2.SOLUTION: A cooling device 100 for cooling semiconductor substrates 3 is provided, the cooling device comprising a container 1 and a coolant 2 introduced into the container 1, the coolant 2 containing boron.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a cooling device for cooling a semiconductor substrate. [Background technology]

[0002] When semiconductors such as LSIs are irradiated with radiation (e.g., neutrons), SEUs (Single Event Upsets, also known as soft errors) occur. On earth, it was thought that the main cause of soft errors was high-energy neutrons, but in recent years, it has become more common to see the occurrence of thermal neutrons (with energy of 10 -8 It has been found that the incidence of soft errors caused by neutrons of around [MeV] is high.

[0003] In order to remove heat generated in the semiconductor substrate, immersion cooling is performed in which the semiconductor substrate is immersed in a cooling device having a container filled with a coolant to cool the semiconductor substrate.

[0004] When high-energy neutrons enter a material containing light elements such as hydrogen, the high-energy neutrons are decelerated, their energy decreases, and they turn into thermal neutrons. Therefore, a semiconductor substrate that is immersion-cooled is irradiated with thermal neutrons that are generated when high-energy neutrons pass through a coolant, which may cause soft errors.

[0005] Non-Patent Document 1 proposes a technology for shielding thermal neutrons using a shielding plate made of polyethylene, silicone rubber, or the like with added boron. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] https: / / jopss.jaea.go.jp / pdfdata / JAERI-M-7016.pdf Summary of the Invention [Problem to be solved by the invention]

[0007] However, in a cooling device filled with a refrigerant, the semiconductor substrate is immersed in the refrigerant and the refrigerant circulates around the semiconductor substrate, which poses the problem that it is difficult to install a shielding plate doped with boron between the refrigerant and the semiconductor.

[0008] The present disclosure has been made in consideration of the above circumstances, and an object of the present disclosure is to provide a cooling device capable of shielding thermal neutrons irradiated to a semiconductor substrate immersed in a refrigerant. [Means for solving the problem]

[0009] A cooling device according to one aspect of the present disclosure is a cooling device for cooling a semiconductor substrate, the cooling device having a container and a coolant injected into the container, the coolant including boron. Effect of the Invention

[0010] According to the present disclosure, it is possible to shield a semiconductor substrate immersed in a coolant from thermal neutrons. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a cooling device according to an embodiment. [Diagram 2] FIG. 2 is an explanatory diagram that illustrates a schematic diagram of the cooling device according to the embodiment. [Diagram 3] FIG. 3 is a graph showing the results of a simulation of the relationship between neutron energy and neutron flux when natural high-energy neutrons are incident on a container. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment will be described with reference to the drawings. Fig. 1 is a perspective view showing the configuration of a cooling device 100 according to an embodiment. As shown in Fig. 1, the cooling device 100 includes a container 1, a refrigerant 2 injected into the container 1, and a cooling unit 4. The cooling device 100 immerses at least one semiconductor substrate 3 in the container 1 to remove heat generated by the semiconductor.

[0013] The container 1 is made of, for example, resin and has a hollow rectangular parallelepiped shape. A refrigerant 2 is poured into the container 1.

[0014] The refrigerant 2 is, for example, a fluorine-based inert liquid to which boron has been added. The fluorine-based inert liquid may include at least one selected from the group consisting of perfluoropolyether (PFPE), perfluorocarbon (PFC), and hydrofluoroether (HFE). Note that the fluorine-based inert liquid is not limited to PFPE, PFC, and HFE, and other refrigerants may be used.

[0015] As the boron to be added to the fluorine-based inert liquid, it is preferable to use either boric acid (H3BO3) or boron oxide (B2O3). In this embodiment, by adding boron to the refrigerant 2 used for water cooling or immersion cooling, the refrigerant 2 itself can have a function of shielding thermal neutrons.

[0016] A plurality of semiconductor substrates 3 are immersed in the coolant 2 poured into the container 1. Fig. 2 is an explanatory diagram showing an example of the arrangement of the semiconductor substrates 3 immersed in the container 1. As shown in Fig. 2, the plurality of semiconductor substrates 3 are arranged in an orderly manner, parallel to each other and at equal intervals.

[0017] For example, a semiconductor substrate 3 constituting a server generates a large amount of heat and therefore needs to be cooled. By immersing the semiconductor substrate 3 in the refrigerant 2 of the cooling device 100, the heat generated in the semiconductor substrate 3 is discharged to the outside.

[0018] The cooling unit 4 has a shape in which a metal pipe is wound in a spiral shape. The inside of the container 1 is cooled by circulating cooling water or a refrigerant in the cooling unit 4. That is, when the semiconductor substrate 3 is immersed in the cooling device 100, the refrigerant 2 is evaporated into steam 6 by the heat released from the semiconductor substrate 3. The steam 6 is cooled by the cooling unit 4, turns into droplets 5, and is returned to the liquid refrigerant 2 again.

[0019] Next, a description will be given of an embodiment using the above-mentioned cooling device 100. In this embodiment, a case where 1% boron oxide is added to HFE (hydrofluoroether) as the refrigerant to be injected into the container 1 will be described.

[0020] FIG. 3 is a graph showing the results of a simulation of the relationship between neutron energy and neutron flux when high-energy neutrons from nature are incident on a cubic container 1 with dimensions of 1 m length, 1 m width and 1 m height.

[0021] Curve s1 in Figure 3 is a graph showing the change in the neutron spectrum in nature calculated using EXPACS (a model for evaluating the intensity of cosmic rays in the atmosphere). The measurement was taken in Tokyo at a height of 0 m above sea level in an ideal atmosphere.

[0022] Curve s2 is the neutron spectrum at the center of the vessel 1 when HFE is used as the refrigerant 2. As shown by curve s2, the neutron energy is reduced by 3.0×10 -7 In the region above [MeV], the number of neutrons decreases. However, -8 ~1.0×10 -7 It can be seen that the number of neutrons is significantly increased in the thermal neutron region around [MeV]. Therefore, when the semiconductor substrate 3 is immersed in the coolant 2, most of the neutrons irradiated to the semiconductor substrate 3 are thermal neutrons, and it is expected that soft errors due to thermal neutrons will increase significantly.

[0023] On the other hand, the curve s3 shown in FIG. 3 is a graph showing the change in the neutron spectrum at the center of the container 1 when 1% boron oxide is added to HFE. In the curve s3, the neutron spectrum at 1.0×10 -7 It can be seen that in the region below [MeV], the thermal neutron flux is reduced by nearly two orders of magnitude compared to curve s2. This confirmed that soft errors caused by thermal neutrons can be significantly reduced.

[0024] Thus, the cooling device 100 according to this embodiment is a cooling device 100 for cooling a semiconductor substrate 3, and includes the container 1 and the coolant 2 injected into the container 1, where the coolant 2 contains boron.

[0025] In this embodiment, thermal neutrons that cause soft errors are blocked by adding boron to the water-cooling or immersion-cooling coolant 2. This makes it possible to significantly reduce soft errors caused by thermal neutrons, thereby improving the reliability of electronic devices that use the semiconductor substrate 3.

[0026] In this embodiment, a cooling unit 4 is provided that cools the refrigerant evaporated in the container 1. Therefore, the refrigerant 2 evaporated in the container 1 can be cooled and returned to a liquid refrigerant again.

[0027] In this embodiment, a fluorine-based inert liquid is used as the coolant 2. This makes it possible to efficiently cool the semiconductor substrate 3 immersed in the coolant 2. The fluorine-based inert liquid contains at least one selected from the group consisting of perfluoropolyether (PFPE), perfluorocarbon (PFC), and hydrofluoroether (HFE). This makes it possible to efficiently cool the semiconductor substrate 3 immersed in the coolant 2.

[0028] In this embodiment, boron includes at least one of boric acid (H3BO3) and boron oxide (B2O3). Therefore, boron can be easily added to the refrigerant 2.

[0029] It should be noted that the present disclosure is not limited to the above-described embodiment, and various modifications are possible within the scope of the present disclosure. [Explanation of symbols]

[0030] 1 container 2. Refrigerant 3. Semiconductor Substrate 4 Cooling section 5 droplets 6. Steam 100 Cooling device

Claims

1. A cooling device for cooling a semiconductor substrate, comprising: A container; A refrigerant injected into the container, The refrigerant contains boron Cooling device.

2. The cooling unit is provided in the container and cools the refrigerant evaporated in the container. The cooling device according to claim 1 .

3. The refrigerant includes a fluorine-based inert liquid. The cooling device according to claim 1 or 2.

4. The fluorine-based inert liquid includes at least one selected from the group consisting of perfluoropolyether (PFPE), perfluorocarbon (PFC), and hydrofluoroether (HFE). The cooling device according to claim 3.

5. The boron includes at least one of boric acid and boron oxide. The cooling device according to claim 1 or 2.

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