Heat equalizing unit for semiconductor chip

Abstract

To facilitate temperature control of a semiconductor chip in thermal management in buildings such as data centers.SOLUTION: In a heat equalizing unit for a semiconductor chip, a first cellulose layer is composed of a porous cellulose base material and a second nanocellulose layer 112 provided on a cellulose base material surface and in a gap inside a cellulose base material layer, and has a structure in which a metal mesh layer 13 and the second nanocellulose layer on the surface of the first cellulose layer are bonded via a first nanocellulose material 20 and a second nanocellulose material in a porous cellulose base material gap. At least a part of the second cellulose layer bonded to the metal mesh layer via the first nanocellulose layer is divided and arranged, a package surface of the semiconductor chip is fitted to a first exposed part in which the metal mesh layer is exposed in a generated gap part via an adhesive having thermal conductivity, and heat generated from the semiconductor chip includes the metal mesh layer via the metal mesh layer.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a unit having a heat-soaking function for semiconductor chips, which uses a composite of a cellulose material and a metal material. [Background technology]

[0002] In recent years, with the advancement of AI technology, thermal management to control and suppress temperature increases in the semiconductor integrated circuits that make up information equipment has become important in business buildings such as data centers that are equipped with a large number of information equipment, such as servers that store large amounts of data known as big data, which is necessary for machine learning, one of the fundamental methods of AI technology, and processors that process the large amounts of data within the servers.

[0003] Semiconductor integrated circuits are generally supplied as semiconductor chips sealed in packaging materials, and as a means of thermal management, heat dissipation technologies, such as heat dissipation sheet technology, which dissipate heat generated in the semiconductor chip from the surface of the package to the outside have been put into practical use.

[0004] Meanwhile, in terms of materials used in industrial products, it is becoming increasingly important to develop and commercialize domestically sourced, natural alternative materials, rather than relying solely on imported petroleum for the plastics and polymers used in conventional products, in light of efforts toward a sustainable society, such as meeting the SDGs and addressing the issue of microplastics. From this perspective, technology has been developed to use naturally derived cellulose materials in the heat-dissipating sheets mentioned above.

[0005] Patent Document 1 discloses a technique for providing a heat dissipation material with high thermal conductivity and bendability, using a composite of thermally conductive inorganic particles and cellulose nanofibers. Patent Document 2 discloses a technique for providing a thermally conductive member having high thermal conductivity by using a cellulose fiber dispersion composite and heat-dissipating inorganic particles. Patent Document 3 discloses a technique for providing a resin molded article with high thermal conductivity using a heat-dissipating resin composition containing improved cellulose and a resin, and further inorganic particles. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-79202 [Patent Document 2] Patent Publication No. 2021-95486 [Patent Document 3] Patent Publication No. 2021-50327 Summary of the Invention [Problem to be solved by the invention]

[0007] In the methods using cellulose materials and inorganic materials disclosed in Patent Documents 1, 2, and 3, etc., a technology for combining materials at the particle level is described, but there is no description of a technology that provides a heat equalization function that takes into account the spatial environment to facilitate temperature control of semiconductor chips in thermal management within buildings such as air-conditioned data centers where a large number of information devices equipped with a large number of semiconductor chips are installed.

[0008] The present invention aims to provide a function to equalize the heat generated by semiconductor chips in a spatial environment where information equipment equipped with a large number of semiconductor chips is installed, through heat exchange with an air-conditioned spatial environment above or with separately installed cooling pipes, thereby facilitating temperature control in thermal management within buildings such as data centers. [Means for solving the problem]

[0009] The present invention provides a means for solving the above problem by providing a heat equalization unit having a structure in which a first cellulose layer, a second cellulose layer, and a metal mesh layer disposed between the first and second cellulose layers are bonded together with a first nanocellulose material containing naturally occurring cellulose nanofibers or cellulose nanocrystals obtained from plants, fungi, bacteria, marine organisms, etc.

[0010] In the present invention, the first cellulose layer is composed of a porous cellulose substrate and a second nanocellulose layer provided on the surface of the cellulose substrate and in the voids inside the cellulose substrate layer, The metal mesh layer and the second nanocellulose layer on the surface of the first cellulose layer have a structure in which they are bonded via the first nanocellulose material and the second nanocellulose material in the voids of the porous cellulose substrate; At least a portion of the second cellulose layer bonded to the metal mesh layer via the first nanocellulose layer is divided and arranged, and the package surface of the semiconductor chip is fitted to the first exposed portion where the metal mesh layer is exposed in the resulting gap portion via a thermally conductive adhesive; Heat generated from the semiconductor chip is transferred through the metal mesh layer, the first nanocellulose material encompassing the metal mesh layer, and the second nanocellulose material in the porous cellulose substrate voids of the first cellulose layer to the second nanocellulose layer on the surface of the first cellulose layer; It has the function of suppressing the temperature rise of semiconductor chips by exchanging heat with the air-conditioned space above. The second cellulose layer solves the above problem by providing a heat equalization unit with an insulating function that prevents heat exchange between the metal mesh layer and the underlying spatial environment, which includes warm air caused by heat generated by information equipment.

[0011] The above problem is solved by providing a heat equalizing unit having the function of promoting heat exchange between the semiconductor chip package surface and the air-conditioned space environment by bending the heat equalizing unit of the present invention and increasing the surface area per unit installation area of ​​the heat equalizing unit that comes into contact with the space environment above.

[0012] a cooling pipe containing a cooling fluid such as water or a refrigerant is joined to a second exposed portion at an end of the heat equalizing unit of the present invention, where the second cellulose layer is not provided and the lower surface of the metal mesh layer is exposed; The above-mentioned problem is solved by a heat equalizing unit having a function of further suppressing the temperature rise of the semiconductor chip by heat exchange of the heat generated in the semiconductor chip in the cooling pipe as well. [Effects of the Invention]

[0013] The heat equalization unit of the present invention can suppress the effects of heat generated by information equipment in an air-conditioned spatial environment such as a building, such as a data center, while promoting heat exchange between semiconductor chips and the air-conditioned spatial environment or cooling pipes, thereby providing a means for facilitating temperature control of semiconductor chips in thermal management within the building. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram of a heat equalizing unit for semiconductor chips according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view of a heat equalizing unit for semiconductor chips according to the present invention. [Figure 3] FIG. 3 is a cross-sectional view showing a semiconductor chip heat equalizing unit of the present invention bonded to a semiconductor chip package. [Figure 4] FIG. 4 is a schematic diagram showing the semiconductor chip heat equalizing unit of the present invention bent and the semiconductor chip package bonded thereto. [Figure 5] FIG. 5 is a schematic diagram showing the semiconductor chip heat equalizing unit of the present invention bonded to the semiconductor chip package and cooling pipe. DETAILED DESCRIPTION OF THE INVENTION

[0015] Examples of the present invention will be described below. The following examples are representative embodiments of the present invention, but the present invention is not limited to these embodiments. [Example]

[0016] As shown in the schematic diagram in Figure 1, a first cellulose layer 11 made of porous Japanese paper perforated with a pinholder and measuring approximately 3 cm wide, 8 cm long, and 0.2 mm thick was sandwiched between a second cellulose layer 12 made of Japanese paper measuring approximately 3 cm wide, 8 cm long, and 0.2 mm thick. A metal mesh layer 13 made of 100-mesh copper with a wire diameter of 0.1 mm was sandwiched between the first cellulose layer 11 and the second cellulose layer 12. A first nanocellulose material in the form of a slurry with a concentration of 2% by weight using water as the solvent was then applied between the first cellulose layer 11 and the second cellulose layer 12 and the metal mesh layer, as well as inside the openings of the metal mesh layer. A second nanocellulose material in the form of a slurry with a concentration of 2% by weight using water as the solvent was then applied to the surface of the first cellulose layer, allowing it to penetrate into the voids inside the first cellulose layer. The resulting mixture was then dried, bonding the first cellulose layer 11, the metal mesh layer 13, and the second cellulose layer 12 together.

[0017] As shown in the cross-sectional schematic diagram of FIG. 2, the first cellulose layer is composed of a second nanocellulose layer 112 formed on the surface and in the internal voids of a porous cellulose substrate layer 111, The first nanocellulose layer 20, which includes the metal mesh layer 13, is bonded to the second nanocellulose layer 112, forming a path for heat transfer from the metal mesh layer 13 to the surface of the first cellulose layer.

[0018] As shown in the overall schematic diagram of Figure 3, the second cellulose layer is divided into two halves, left and right, and a metal mesh layer exposed in the gap is bonded to a semiconductor chip package 31 using a thermally conductive adhesive. Heat generated from the surface of the semiconductor chip package is transferred to the thermally conductive adhesive and metal mesh layer, then to the first and second nanocellulose layers, and heat is exchanged with the air-conditioned space above on the surface of the first cellulose layer. On the other hand, the second cellulose layer 12 acts as a heat insulating layer to suppress heat exchange between the metal mesh layer and the underlying spatial environment, which includes warm air caused by heat generated by the information equipment.

[0019] 4 shows an embodiment of the present invention in which the heat equalizing unit 2 is bent to increase the surface area in contact with the upper air environment per unit area where the heat equalizing unit is installed, thereby promoting heat exchange between the surface of the attached semiconductor chip package 31 and the air-conditioned upper air environment. This has the effect of suppressing the temperature rise of the semiconductor chip by approximately 1°C.

[0020] 5 shows an embodiment of the present invention in which cooling pipes 51 containing cooling water are attached to the exposed metal mesh layer at both ends of the heat soaking unit without the second cellulose layer, providing a heat exchange effect between the cooling pipes and the heat transferred from the semiconductor chip package 41 to the metal mesh layer. This effectively suppressed the temperature rise of the semiconductor chip by approximately 2°C.

[0021] The heat equalizing unit according to the present invention is not limited to the above-described embodiment, and may be implemented in other forms and by other manufacturing methods. For example, the thickness and size of each of the first cellulose layer, the second cellulose layer, and the metal mesh layer are not limited to the above dimensions, and may be optimized depending on the application of the heat soaking unit. For example, the porous substrate layer of the first cellulose layer is not limited to the above-mentioned Japanese paper perforated with a pinholder, and a porous cellulose material may also be used. For example, the second cellulose layer is not limited to the second Japanese paper described above, and may be made of a foam material or a laminate of multiple heat insulating materials. For example, the metal mesh layer is not limited to the copper mentioned above, and may be made of a metal material such as aluminum. For example, the shape of the bent heat equalizing unit is not limited to the zigzag shape described above, but may be a U-shape, a box shape, a box shape with a partial opening, a spherical shape, or any other shape that increases the surface area in contact with the surrounding space environment per installation area and has the effect of promoting heat exchange, including convection. For example, the cooling pipes are not limited to being provided at both ends of the heat equalizing unit as described above, but may be provided at either end. For example, the surface of the semiconductor chip package or the surface of the cooling pipe may be modified by a surface treatment method such as coating or plasma irradiation to improve the bonding strength of the fitting structure of the heat equalizing unit according to the present invention. [Industrial Applicability]

[0022] The heat equalization unit of the present invention has industrial applicability not only in the data center mentioned above, but also in thermal management of heat emitted from semiconductor chips in spatial environments within buildings such as homes and offices, and as an electromagnetic wave shield to protect semiconductor chips from external electromagnetic waves. [Explanation of symbols]

[0023] 11... first cellulose layer; 12... second cellulose layer; 13. Metal mesh layer, 2. Heat equalization unit, 20... The first nanocellulose material, 111···Porous cellulose substrate layer; 112... Second nanocellulose material, 31. Semiconductor chip packaging, 51...Cooling pipe

Claims

1. At least a metal mesh layer is provided between the first cellulose layer and the second cellulose layer; A heat soaking unit for semiconductor chips, characterized by having a structure in which a first nanocellulose material is arranged between a first cellulose layer and a metal mesh layer, within openings in the metal mesh layer, and between the metal mesh layer and a second cellulose layer.

2. The first cellulose layer comprises a cellulose substrate layer made of a porous cellulose material; A surface layer made of a second nanocellulose material provided on the surface of the cellulose substrate layer; the second cellulose material infiltrating voids within the cellulose substrate layer; The heat equalization unit for semiconductor chips according to claim 1, characterized in that the surface layer and the metal mesh layer have a structure in which they are bonded via the second nanocellulose material.

3. the second cellulose layer is divided and arranged with gaps between them, 3. The heat equalizing unit for semiconductor chips according to claim 2, wherein the gap has a structure in which a first exposed portion is provided in which the metal mesh layer is exposed.

4. 4. The heat equalizing unit for semiconductor chips according to claim 3, wherein said heat equalizing unit has a structure in which at least a part of said unit is bent.

5. providing a second exposed portion in which the metal mesh layer is exposed in the second cellulose layer; 5. The semiconductor chip heat equalizing unit according to claim 3, wherein a cooling pipe is connected to the second exposed portion.

Images