Vapor chamber and semiconductor package incorporating same

Abstract

The purpose of the present invention is to provide: a vapor chamber capable of suppressing a rise in temperature of a semiconductor element by efficiently transporting heat generated from the semiconductor element; and a semiconductor package on which the vapor chamber is mounted.　By using a vapor chamber provided with a heat diffusion member (2) having a thermal conductivity of 500 W / mK or more in a plane direction orthogonal to a first outer surface and / or a second outer surface of a chamber body (1) in which a liquid substance is sealed in an internal sealed space, it is possible to suppress the rise in temperature of the semiconductor element provided on the heat diffusion member.

Description

[Technical Field]

[0001] The present invention relates to a vapor chamber having a heat diffusion member. [Background technology]

[0002] In recent years, the performance of electronic devices such as personal computers has improved dramatically. However, temperature rise due to heat generated by semiconductor elements such as CPUs has become a problem, necessitating the development of semiconductor packages with superior cooling performance. Vapor chambers are sometimes used as a means of suppressing temperature rise in semiconductor packages. To improve the heat transport capacity of a vapor chamber, it is necessary to ensure smooth evaporation and condensation of the liquid contained within the vapor chamber body. If the balance between evaporation and condensation is significantly disrupted, a decrease in heat transport known as dryout occurs, so the effective areas of the evaporation and condensation sections must be taken into consideration.

[0003] As an example of a vapor chamber with improved heat transport capacity, Patent Document 1 discloses that a large number of fins are provided inside the chamber body of the vapor chamber and the fins are connected to the upper or lower plate to increase the amount of liquid reflux and increase the amount of heat transport. Patent Document 2 also discloses that the vapor chamber and the substrate are connected via a heat conductive part such as metal, and the heat accumulated in the vapor chamber is transferred to the substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2015-132399 [Patent Document 2] Japanese Patent Publication No. 2018-162949 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the inventors have discovered that with the recent trend toward ever-increasing performance in electronic devices, the heat output of semiconductor elements has increased and their surface area has become smaller, resulting in a decrease in the effective surface area of ​​the evaporation and condensation sections, which in turn reduces the performance of the vapor chamber.

[0006] One aspect of the present invention aims to provide a vapor chamber that can suppress a temperature rise of a semiconductor element by efficiently transporting heat generated from the semiconductor element, and a semiconductor package that incorporates the vapor chamber. [Means for solving the problem]

[0007] The inventors conducted intensive research in light of the above-mentioned problems and discovered that placing a heat diffusion member on the surface of the chamber body of the vapor chamber is effective in improving the actual effective area of ​​the evaporation section, and that increasing the amount of heat transport in the vapor chamber can suppress the temperature rise of the semiconductor element, thereby completing the present invention.

[0008] That is, a vapor chamber according to one aspect of the present invention relates to the following. (I) a chamber body having a sealed space therein; A liquid material sealed in the chamber body; A vapor chamber having a heat diffusion member, the chamber body has a first outer surface, a first inner surface that is the reverse side of the first outer surface, a second outer surface, and a second inner surface that is the reverse side of the second outer surface; The sealed space is provided between the first inner surface and the second inner surface, the liquid is sealed in the sealed space, and the chamber body is provided with the heat diffusion member on the first outer surface and / or the second outer surface; A vapor chamber in which the heat diffusion member has a thermal conductivity of 500 W / mK or more in a plane direction perpendicular to the first outer surface or the second outer surface of the chamber body. [Effects of the Invention]

[0009] According to one embodiment of the present invention, a vapor chamber capable of increasing the amount of heat transport can be provided. In addition, by using the vapor chamber according to one embodiment of the present invention, a semiconductor package capable of suppressing a temperature rise of a semiconductor element can be provided. [Brief explanation of the drawings]

[0010] [Figure 1] First embodiment of the vapor chamber of the present invention [Figure 2] 2 is a cross-section of a second embodiment of the vapor chamber of the present invention; [Figure 3] 3 is a cross-section of a third embodiment of the vapor chamber of the present invention; [Figure 4] 4 is a cross-section of a fourth embodiment of the vapor chamber of the present invention; [Figure 5] First embodiment of a semiconductor package equipped with the vapor chamber of the first embodiment [Figure 6] 10 is a cross-sectional view of a second embodiment of a semiconductor package equipped with a vapor chamber according to the third embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0011] One aspect of the present invention is described below, but the present invention is not limited thereto. The present invention is not limited to the respective configurations described below, and various modifications are possible within the scope of the claims. Furthermore, embodiments or examples obtained by combining the technical means disclosed in different embodiments or examples are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. All patent documents described in this specification are incorporated herein by reference. Furthermore, unless otherwise specified in this specification, the term "A to B" representing a numerical range means "greater than or equal to A (including A and greater than A) and less than or equal to B (including B and less than B)."

[0012] A vapor chamber according to one embodiment of the present invention comprises a chamber body (1) having a sealed space therein, a liquid (11) sealed within the chamber body, and a heat diffusion member (2). The chamber body has a first outer surface, a first inner surface opposite the first outer surface, a second outer surface, and a second inner surface opposite the second outer surface. The sealed space is defined between the first inner surface and the second inner surface, and the liquid (11) is sealed within the sealed space. The chamber body (1) is provided with the heat diffusion member (2) on the first outer surface and / or the second outer surface. The heat diffusion member (2) has a thermal conductivity of 500 W / mK or greater in a plane perpendicular to the first or second outer surface of the chamber body (1). Here, "a plane perpendicular to the first or second outer surface" refers to a plane perpendicular to the first or second outer surface. Thermal conductivity (W / mK) is the temperature difference between the two sides of a 1m thick plate. 2 The thermal conductivity in the plane direction is the amount of heat flowing through the material. The thermal conductivity in the plane direction is expressed as the thermal diffusivity in the plane direction multiplied by the specific heat multiplied by the density. The thermal diffusivity in the plane direction was measured by cutting the sample into a 10 mm square and using a Netsch Japan LFA447 with the xenon flash method. The specific heat was measured at 50°C using a 10 mg sample with the DSC method. The density was calculated by cutting the sample into a 10 mm square and measuring the length, width, and height with a Mitutoyo micrometer to determine the volume, then dividing the weight of the sample by the volume.

[0013] FIG. 1 shows a first embodiment of the vapor chamber of the present invention.

[0014] 2 to 4 show cross sections of second to fourth embodiments of the vapor chamber of the present invention.

[0015] Below, each component constituting a vapor chamber according to one embodiment of the present invention will be described. <Chamber body (1)> The chamber body (1) used in a vapor chamber according to one embodiment of the present invention has a first outer surface, a first inner surface opposite the first outer surface, a second outer surface, and a second inner surface opposite the second outer surface, with a sealed space between the first and second inner surfaces. The chamber body (1) having the sealed space is not particularly limited as long as it is made of a material and has a structure that prevents leakage of the liquid substance (11) described below. Metal is preferred as the material, and copper or aluminum is particularly preferred from the viewpoint of excellent thermal conductivity. Furthermore, the structure can be made using known techniques. From the viewpoint of reliability in preventing leakage of the liquid substance (11), a hollow cylindrical chamber body is preferably made of, for example, a flat plate forming the first outer surface and the first inner surface and a bottomed cylinder forming the second outer surface and the second inner surface. From the viewpoint of ease of manufacture, a rectangular flat plate and a rectangular bottomed cylinder are more preferred. An airtight hollow cylindrical chamber body can be manufactured by joining the ends of the flat plate and the bottomed cylinder to each other by known techniques such as diffusion bonding, brazing, or soldering. Because it is necessary to reduce the pressure inside the chamber body using a vacuum pump and pour in the liquid material (11), it is possible to combine multiple methods as appropriate, such as joining the ends of the flat plate and the bottomed cylinder except for the pouring port by diffusion bonding, and then pouring in the liquid material (11) and then joining the pouring port by brazing.

[0016] Furthermore, in order to smoothly evaporate and condense the liquid material (11), which will be described later, the chamber body (1) preferably has a porous wick disposed on the entire inner wall surface, including the first and second inner surfaces of the chamber body (1). Alternatively, a microstructure may be formed by etching or the like.

[0017] The size of the chamber body (1) used in one embodiment of the vapor chamber of the present invention is preferably selected taking into consideration the size of the semiconductor element (5) and heat sink (6) described below. For example, a size of 100 mm x 100 mm can be used, but is not particularly limited.

[0018] The total thickness of the chamber body (1) used in the vapor chamber according to one embodiment of the present invention can be in the range of 0.5 to 10.0 mm for ease of manufacture and handling, but is not particularly limited.

[0019] <Liquids (11)> The liquid (11) used in the vapor chamber according to one embodiment of the present invention is sealed inside the chamber body (1). When the liquid (11) reaches a temperature above its boiling point, it evaporates on the inner wall surface of the chamber body (1), and the gas moves through the hollow portion of the chamber body (1). When the liquid (11) reaches a temperature below its boiling point, it condenses and the liquid moves along the inner wall surface. This circulation allows for semi-permanent heat transport. The type of liquid (11) is not particularly limited, but preferred examples include pure water, alcohol, and ammonia. These may be used alone or in combination, but pure water is particularly preferred from the standpoints of safety and cost.

[0020] <Heat diffusion material (2)> The heat diffusion member (2) used in a vapor chamber according to one embodiment of the present invention is disposed on the first and / or second outer surface of the chamber body (1) and has a thermal conductivity of 500 W / mK or greater in a plane perpendicular to the first and / or second outer surface of the chamber body (1). Having a thermal conductivity of 500 W / mK or greater spreads heat from the semiconductor element (5) (described below) within the plane while minimizing loss due to thermal resistance. This results in a larger effective area of ​​the evaporation section, increasing the heat transport rate of the vapor chamber according to one embodiment of the present invention. The higher the thermal conductivity of the heat diffusion member (2), the better, with a thermal conductivity of 800 W / mK or greater being more preferable, and a thermal conductivity of 1000 W / mK or greater being particularly preferable.

[0021] <Anisotropic graphite> From the viewpoint of thermal conductivity, the material of the heat diffusion member (2) used in the vapor chamber according to one embodiment of the present invention preferably contains anisotropic graphite. Anisotropic graphite is a material in which many graphite layers are stacked, and has high thermal conductivity along the crystal orientation plane. In addition, it generally has low thermal conductivity in a direction perpendicular to the crystal orientation plane. There are no particular limitations on the method for producing anisotropic graphite, but it can be produced by cutting a graphite block. Methods for cutting the graphite block include a diamond cutter, a wire saw, and machining. A wire saw is preferred from the viewpoint of easy processing into a rectangular parallelepiped shape.

[0022] The surface of the anisotropic graphite may be polished or roughened, and known techniques such as filing, buffing, and blasting can be used as appropriate.

[0023] As described above, the heat diffusion member (2) has a thermal conductivity of 500 W / mK or greater in a plane perpendicular to the first and / or second outer surfaces of the chamber body (1). As shown in the vapor chamber (100) of FIGS. 1 and 2, when the heat diffusion member (2) is disposed on the first outer surface of the chamber body (1) so that the crystal orientation plane of the anisotropic graphite is perpendicular to the first outer surface and parallel to the YZ plane, the heat diffusion member (2) has a thermal conductivity of 500 W / mK or greater in the plane direction of the YZ plane. The vertical line in the Z-axis direction of the heat diffusion member (2) of the vapor chamber (100) in FIG. 2 schematically indicates the crystal orientation plane of the anisotropic graphite material. For example, when the heat diffusion member (2) is disposed on the first outer surface in a state rotated 90 degrees about the Z axis from the state shown in FIGS. 1 and 2, the crystal orientation plane is parallel to the XZ plane, and the heat diffusion member (2) has a thermal conductivity of 500 W / mK or greater in the plane direction of the XZ plane. The arrangement of the heat diffusion member (2) on the first outer surface and / or the second outer surface is not limited to the above-mentioned case, and the heat diffusion member (2) may be arranged on the first outer surface and / or the second outer surface so that the crystal orientation plane of the anisotropic graphite is parallel to a plane perpendicular to the first outer surface and / or the second outer surface.

[0024] The crystal orientation plane of the anisotropic graphite may not be parallel to the plane direction perpendicular to the first outer surface and / or the second outer surface, but may form a predetermined angle with the plane direction perpendicular to the first outer surface and / or the second outer surface. For example, as shown in the vapor chamber (101) of FIG. 2, when the heat diffusion member (2) is disposed on the first outer surface, the crystal orientation plane may form a predetermined angle with the YZ plane. From the viewpoint of ease of handling of the heat diffusion member (2), the crystal orientation plane preferably forms an angle of ±10 degrees or less with the YZ plane, and more preferably an angle of ±5 degrees or less. This is not limited to this case, and the crystal orientation plane may preferably form an angle of ±10 degrees or less, more preferably ±5 degrees or less, with respect to the plane perpendicular to the first outer surface and / or the second outer surface. It is particularly preferable that the crystal orientation plane of the anisotropic graphite be substantially parallel to the plane direction perpendicular to the first outer surface and / or the second outer surface so that the heat diffusion member (2) has a thermal conductivity of 500 W / mK or more in the plane direction perpendicular to the first outer surface and / or the second outer surface of the chamber body (1).

[0025] <Graphite Block> The graphite block is not particularly limited, and may be a polymer decomposed graphite block, a pyrolytic graphite block, an extruded graphite block, a molded graphite block, etc. From the viewpoint of high thermal conductivity and excellent heat transfer performance of anisotropic graphite, a polymer decomposed graphite block and a pyrolytic graphite block are preferred.

[0026] The graphite block can be produced, for example, by introducing a carbonaceous gas such as methane into a furnace and heating it to approximately 2000°C using a heater to form fine carbon nuclei. The formed carbon nuclei are then deposited in layers on a substrate to obtain a pyrolytic graphite block. Alternatively, the graphite block can be produced by laminating multiple polymer films such as polyimide resins and then heat-treating them while pressing. Specifically, to obtain a graphite block from a polymer film, the starting material, a multilayered polymer film, is first preheated to approximately 1000°C under reduced pressure or in an inert gas to carbonize it into a carbonized block. The carbonized block is then graphitized by heat-treating it to a temperature of 2000°C or higher, preferably 2800°C or higher, under an inert gas atmosphere while pressing and pressurizing. This allows for the formation of a favorable graphite crystalline structure, resulting in a graphite block with excellent thermal conductivity.

[0027] Specific examples of methods for producing graphite blocks include the method described in International Publication No. 2015 / 129317.

[0028] <Size of the heat diffusion member (2)> The thickness of the heat diffusion member (2) used in the vapor chamber according to one embodiment of the present invention is preferably in the range of 0.5 to 10.0 mm. If the thickness is thinner than 0.5 mm, the effective area of ​​the evaporation section cannot be sufficiently expanded, and the heat transport rate of the vapor chamber according to one embodiment of the present invention does not increase, which may result in an ineffective suppression of the temperature rise of the semiconductor element. On the other hand, if the thickness is thicker than 10.0 mm, the thermal resistance of the heat diffusion member (2) itself increases, which again results in an ineffective increase in the heat transport rate of the vapor chamber according to one embodiment of the present invention, and therefore may result in an ineffective suppression of the temperature rise of the semiconductor element. In order to expand the effective area of ​​the evaporation section and reduce its own thermal resistance, the lower limit of the thickness of the heat diffusion member (2) is more preferably 0.8 mm, and particularly preferably 1.0 mm. Furthermore, the upper limit is more preferably 5.0 mm, and particularly preferably 3.0 mm.

[0029] Furthermore, the surface area of ​​the heat diffusion member (2) is preferably in the range of 4 to 100% of the area of ​​the first outer surface and / or the second outer surface of the chamber body (1). If the area is less than 4%, the effective area of ​​the evaporation section cannot be sufficiently expanded, and the heat transport rate of the vapor chamber according to one embodiment of the present invention does not increase, which may result in an inability to achieve the effect of suppressing the temperature rise of the semiconductor element. On the other hand, even if the area is greater than 100%, the effect of increasing the heat transport rate of the vapor chamber according to one embodiment of the present invention in proportion to the area cannot be expected. From the viewpoint of increasing the heat transport rate of the vapor chamber according to one embodiment of the present invention and efficiently achieving the effect of suppressing the temperature rise of the semiconductor element, a more preferable lower limit is 8%. A more preferable upper limit is 50%.

[0030] The actual size of the heat diffusion member (2) is not particularly limited as long as its surface area is within a range of 4 to 100% of the area of ​​the first outer surface and / or second outer surface of the chamber body (1), as described above. However, from a practical standpoint, a size in the range of 10 mm × 10 mm to 100 mm × 100 mm is preferable. If it is smaller than 10 mm × 10 mm, the effective area of ​​the evaporation section cannot be sufficiently expanded, and it is difficult to obtain the effect of suppressing the temperature rise of the semiconductor element. On the other hand, even if it is larger than 100 mm × 100 mm, it is difficult to obtain a greater effect. From the standpoint of expanding the effective area of ​​the evaporation section and efficiently obtaining the effect of suppressing the temperature rise of the semiconductor element, it is more preferable that the lower limit of the heat diffusion member (2) is 20 mm × 20 mm. Furthermore, it is more preferable that the upper limit is 75 mm × 75 mm.

[0031] <First embodiment of the vapor chamber of the present invention> In a first embodiment of the vapor chamber of the present invention, which efficiently achieves the effect of expanding the effective area of ​​the evaporation section and suppressing the temperature rise of semiconductor elements, a heat diffusion member (2) and a chamber main body (1) are bonded via a bonding layer (3), as shown in FIG. 1 . The bonding layer (3) may contain at least one material selected from the group consisting of solder, brazing filler metal, diffusion bonding, and thermally conductive grease. From the viewpoint of minimizing the thermal resistance present in the bonding layer (3), solder, brazing filler metal, and diffusion bonding are preferred, but solder is particularly preferred from the viewpoint of ease of handling. The type of solder is not particularly limited, and solid or paste-like solder can be used as appropriate. Furthermore, the heat diffusion member (2) may be disposed and bonded to the first and / or second outer surfaces of the chamber main body (1) in any manner. However, it is more preferable that the heat diffusion member (2) be disposed so that the entire surface of one side is bonded to the chamber main body (1), and it is particularly preferable that the heat diffusion member (2) be disposed approximately in the center of the chamber main body (1). The same applies to the other embodiments of the present invention.

[0032] <Second embodiment of the vapor chamber of the present invention> As a second embodiment of the vapor chamber of the present invention, as shown in Figure 2, at least a portion of the surface of the heat diffusion member (2) of Figure 1 may have a coating layer (4) containing either a metal or a ceramic. By having a coating layer (4) containing either a metal or a ceramic on at least a portion of the surface, damage to the heat diffusion member (2) can be prevented, improving the handleability of the vapor chamber according to one aspect of the present invention. It is preferable that the entire surface facing the semiconductor element is coated, and it is particularly preferable that the entire surface other than the surface facing the bonding layer (3) is coated.

[0033] <Method for forming coating layer (4)> In the second embodiment of the present invention, the coating layer can be formed by known techniques such as plating, sputtering, and thermal spraying, or by joining metal or ceramic plates. When joining metal or ceramic plates, it is preferable to first use known techniques such as drawing, cutting, and bending to form a bottomed part that can cover the heat diffusion member (2), and then join the bottomed part to the heat diffusion member (2) using a metallic brazing filler metal. The bottomed part may also have an offset portion (offset region), which can be appropriately provided to stabilize its placement in the chamber body (1). Metal brazing filler metals have relatively high thermal conductivity and are therefore less likely to cause thermal resistance. The type of metallic brazing filler metal is not particularly limited, but it is preferable for it to contain silver, copper, or titanium in order to maintain high thermal conductivity.

[0034] When a metal brazing material is used, known materials and techniques can be used for the joining method. For example, when active silver brazing is used, active silver brazing having a thickness in the range of 0.005 to 0.05 mm is applied to 1×10 -3 Bonding can be achieved by heating the materials in a vacuum environment of 100 Pa, an argon atmosphere, or a reducing atmosphere such as hydrogen at a temperature in the range of 700 to 1000°C for 10 minutes to 1 hour, and then cooling them to room temperature. In order to improve the bonding condition, weight may be applied during heating.

[0035] The lower limit of the thickness of the coating layer (4) is preferably 0.005 mm, and more preferably 0.01 mm. The upper limit is preferably 0.5 mm, and more preferably 0.3 mm. If the thickness is thinner than 0.005 mm, it is difficult to prevent damage to the heat diffusion member (2). If the thickness is thicker than 0.5 mm, the coating layer itself becomes thermally resistant, which may reduce the amount of heat transport in the vapor chamber, which is undesirable.

[0036] The material for the coating layer (4) is not particularly limited as long as it is a metal or ceramic, but it is preferable to use a material with a thermal conductivity of 100 W / mK or more, such as silver, copper, aluminum, aluminum nitride, etc. If a material with a thermal conductivity of less than 100 W / mK is used, the amount of heat transport in the vapor chamber may decrease due to the influence of the thermal resistance of the coating layer, which is not preferable.

[0037] <Third embodiment of the vapor chamber of the present invention> In a third embodiment of the vapor chamber of the present invention, as shown in FIG. 3, the coating layer (4) may have an offset portion in the surface direction at the end of the heat diffusion member in the surface direction. The provision of such an offset portion has the advantage of facilitating stable placement on the chamber body (1). The minimum width of the offset portion is preferably 0.5 mm, and the maximum width is preferably 5 mm. If the offset portion width is less than 0.5 mm, the offset portion may be easily damaged, resulting in unstable placement. On the other hand, if the offset portion width is greater than 5 mm, there is no particular advantage, and there are concerns about increased material costs and weight. When using known techniques such as plating, sputtering, or thermal spraying, one method of forming the offset portion is to predetermine the offset portion on the chamber body (1) with masking tape, then place the heat diffusion member (2), form the coating layer (4), and then peel off the masking tape. When forming an offset portion by joining a metal or ceramic plate, a method is available in which a metal or ceramic plate is pre-processed using known techniques such as drawing, cutting, bending, etc. into a shape that can cover the heat diffusion member (2) and has an offset portion, and then joined to the heat diffusion member (2) with a metal-based brazing material, as in the second embodiment of the vapor chamber of the present invention described above, and then placed in the chamber body (1).

[0038] <Fourth embodiment of the vapor chamber of the present invention> In a fourth embodiment of the vapor chamber of the present invention, as shown in FIG. 4, a coating layer may cover both sides of the heat diffusion member, and offset portions may be provided in the surface direction at the end portions in the surface direction. The provision of such offset portions has the advantage of suppressing internal stress in the heat diffusion member (2) and facilitating stable placement in the chamber body (1). A width of 0.5 mm or more is sufficient for the offset portions. For example, when forming the offset portions by joining metal or ceramic plates, known techniques such as drawing, cutting, and bending may be used to pre-process the metal or ceramic plate into a shape that can cover the heat diffusion member (2) and has the offset portions. This can then be joined to the heat diffusion member (2) with a metallic brazing material, as in the second embodiment of the vapor chamber of the present invention, and then placed in the chamber body (1).

[0039] <Semiconductor package> A semiconductor package can be formed by joining the heat diffusion member (2) of the vapor chamber according to one aspect of the present invention with a semiconductor element (5). Furthermore, a semiconductor package can be formed by having a heat sink (6) on the side of the chamber body (1) of the vapor chamber according to one aspect of the present invention opposite the side on which the semiconductor element (5) is installed. A semiconductor package equipped with a vapor chamber according to one aspect of the present invention can efficiently suppress temperature rise of the semiconductor element. FIG. 5 shows a first embodiment of a semiconductor package equipped with a vapor chamber according to the first embodiment of the present invention. FIG. 6 shows a cross section of a second embodiment of a semiconductor package equipped with a vapor chamber according to the third embodiment of the present invention. Below, each component constituting a semiconductor package equipped with a vapor chamber according to one aspect of the present invention will be described.

[0040] <Semiconductor element (5)> The semiconductor element (5) used in the semiconductor package according to one embodiment of the present invention is not particularly limited, but examples thereof include a CPU, a GPU, an FPGA, a transistor, a diode, and a memory.

[0041] <Heat sink (6)> The heat sink (6) used in the semiconductor package according to one embodiment of the present invention is not particularly limited, and known types such as parallel comb fins, pin fins, corrugated fins, water-cooled heat sinks, Peltier modules, etc. In the case of parallel comb fins, pin fins, and corrugated fins, a motor fan may be used in combination to promote cooling.

[0042] <First embodiment of semiconductor package> In a semiconductor package equipped with the vapor chamber of the first embodiment of the present invention, a first embodiment for efficiently achieving the effect of increasing the effective area of ​​the evaporation section and suppressing the temperature rise of the semiconductor element can be configured in the following order from the semiconductor element (5) side, as shown in FIG. 5 : semiconductor element (5), heat diffusion member (2), chamber main body (1), and heat sink (6). Methods for joining the heat diffusion member (2) and the semiconductor element (5) can be known, such as solder, thermally conductive grease, and thermally conductive sheet. However, solder is preferred from the viewpoint of minimizing thermal resistance. The type of solder is not particularly limited, and solid or paste-like solder can be used as appropriate. Furthermore, methods for joining the chamber main body (1) and the heat sink (6) can be known, such as solder, brazing filler metal, diffusion bonding, thermally conductive grease, and thermally conductive sheet. However, solder, brazing filler metal, and diffusion bonding are preferred from the viewpoint of minimizing thermal resistance, and solder is particularly preferred from the viewpoint of ease of handling. The type of solder is not particularly limited, and solid or paste-like solder can be used as appropriate.

[0043] <Second embodiment of semiconductor package> In a semiconductor package equipped with the vapor chamber according to the third embodiment of the present invention, a second embodiment for efficiently suppressing the temperature rise of the semiconductor element by increasing the effective area of ​​the evaporation section (7) can be shown in FIG. 6. The semiconductor package includes, from the semiconductor element side, a semiconductor element (5), a heat diffusion member (2) provided with a coating layer (4) on the semiconductor element (5), a chamber body (1), and a heat sink (6). The coating layer (4) can be formed using a method similar to that used in the second to fourth embodiments of the vapor chamber according to the present invention. Furthermore, the method for joining the heat diffusion member (2) to the semiconductor element (5) and the method for joining the chamber body (1) to the heat sink (6) can be similar to that used in the first embodiment of the semiconductor package described above. In the semiconductor package equipped with the vapor chamber according to the third embodiment of the present invention, as shown in FIG. 6, the area of ​​the evaporation section (7) is clearly larger than the area of ​​the semiconductor element (5), and the area of ​​the condensation section (8) is also sufficiently large, thereby enabling efficient suppression of the temperature rise of the semiconductor element. [Example]

[0044] Examples of the present invention will be described below. (Temperature evaluation of semiconductor devices) In Examples 1 to 9 and Comparative Examples 2 to 4, a semiconductor element (10 mm x 10 mm) was bonded to the center of the surface of the heat diffusion member opposite the chamber body side via thermal conductive grease (model number: G-775, manufactured by Shin-Etsu Chemical Co., Ltd.) and to the center of the first outer surface of the chamber body in Comparative Example 1. A water-cooled heat sink (water temperature 25°C) was bonded to the entire second outer surface of the chamber body via the thermal conductive grease to produce a semiconductor package. A 100 W heat was generated in the semiconductor element, and the temperature of the semiconductor element was measured using a thermocouple. If the temperature of the semiconductor element was less than 90°C, the temperature rise suppression effect was evaluated as "A." If it was 90°C or higher but less than 100°C, it was evaluated as "B." If it was 100°C or higher but less than 110°C, it was evaluated as "C." If it was 110°C or higher, it was evaluated as "D." When it was evaluated as "A" or "B," it was determined that the vapor chamber had a high heat transport capacity and was able to suppress the temperature rise of the semiconductor element in the semiconductor package.

[0045] (Production Example 1) The graphite block used as the raw material for the anisotropic graphite A used in the heat diffusion member was manufactured as follows: 20,000 sheets of polyimide film (manufactured by Kaneka Corporation) measuring 100 mm x 100 mm x 12.5 μm in thickness were laminated together and then heated at 40 kg / cm. 2 A graphite block (90 mm x 90 mm, 100 mm thick) was fabricated by heat-treating the material up to 2200°C in an argon atmosphere while pressing it at a pressure of 1000 kJ / cm2. The thermal conductivity of the resulting graphite block was 600 W / mK in the direction parallel to the crystal orientation plane and 5 W / mK in the direction perpendicular to the crystal orientation plane.

[0046] (Production Example 2) The graphite block used as the raw material for the anisotropic graphite B used in the heat diffusion member was manufactured as follows: 20,000 sheets of polyimide film (manufactured by Kaneka Corporation) measuring 100 mm x 100 mm x 12.5 μm in thickness were laminated together and then heated at 40 kg / cm. 2 A graphite block (90 mm x 90 mm, 100 mm thick) was fabricated by heat-treating the material up to 2900°C in an argon atmosphere while pressing it at a pressure of 1000 kJ / cm2. The thermal conductivity of the resulting graphite block was 1500 W / mK in the direction parallel to the crystal orientation plane and 5 W / mK in the direction perpendicular to the crystal orientation plane.

[0047] (Production Example 3) The chamber body was manufactured as follows. A rectangular hollow cylinder measuring 100 mm x 100 mm and 5 mm thick was prepared using a copper flat plate having a surface that would become the first outer surface and a copper cylinder with a bottom that would become the second outer surface. A porous wick was placed over the entire inner wall surface, and the liquid was pure water.

[0048] Example 1 The graphite block obtained in Production Example 1 was cut with a wire saw (model number: WSD-K2, manufactured by Takatori Corporation) to obtain anisotropic graphite A with a planar size of 30 mm × 30 mm and a thickness of 1.5 mm. The anisotropic graphite A had crystal orientation planes aligned along the thickness direction and a thermal conductivity of 600 W / mK. This anisotropic graphite A was used as a heat diffusion member and placed in the center of the first outer surface of the chamber body obtained in Production Example 3 via thermally conductive grease (model number: G-775, manufactured by Shin-Etsu Chemical Co., Ltd.), thereby producing a vapor chamber.

[0049] When the temperature of the semiconductor element was evaluated using the vapor chamber, the temperature of the semiconductor element was 95° C. and the evaluation was "B."

[0050] Example 2 The graphite block obtained in Production Example 2 was cut using a wire saw (model number: WSD-K2, manufactured by Takatori Corporation) to obtain anisotropic graphite B with a planar size of 30 mm × 30 mm and a thickness of 1.5 mm as a heat diffusion member. The anisotropic graphite B had crystal orientation planes aligned along the thickness direction and a thermal conductivity of 1500 W / mK. Masking tape (model number: 851A, manufactured by 3M) was applied to the entire flat surface of the heat diffusion member, and electrolytic plating was performed to form a 0.01 mm-thick Cu coating layer on the surface. The masking tape was then removed to produce a heat diffusion member with a Cu coating layer formed on only one side. The heat diffusion member was placed on the center of the first outer surface of the chamber body obtained in Production Example 3, with thermal conductive grease (model number: G-775, manufactured by Shin-Etsu Chemical Co., Ltd.) interposed between them, so that the exposed graphite surface of the heat diffusion member faced the first outer surface of the chamber body, producing a vapor chamber as shown in Figure 2.

[0051] When the temperature of the semiconductor element was evaluated using the vapor chamber, the temperature of the semiconductor element was 78° C. and the evaluation was "A."

[0052] Example 3 A clad material was prepared in which a 0.013 mm thick activated silver solder (model number: TKC-661, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) was preliminarily formed on a 0.2 mm thick copper plate, and a bottomed part with inner dimensions of 30 mm × 30 mm × 1.5 mm and a 1 mm width offset portion at the end in the planar direction was manufactured by drawing using a mold. Anisotropic graphite B, a heat diffusion member obtained in the same manner as in Example 2, was loaded into the bottomed part, and a 1 × 10 -3 The two were then heat-treated at 780°C for 30 minutes under a vacuum of 100 Pa to uniformly bond them together, producing a heat diffusion member with a 0.2 mm-thick Cu coating layer formed on only one side. The heat diffusion member obtained in Production Example 3 was placed in the center of the first outer surface of the chamber body via thermal conductive grease (model number: G-775, manufactured by Shin-Etsu Chemical Co., Ltd.) so that the exposed graphite surface of the heat diffusion member faced the first outer surface of the chamber body, producing a vapor chamber as shown in Figure 3.

[0053] When the temperature of the semiconductor element was evaluated using the vapor chamber, the temperature of the semiconductor element was 83° C. and the evaluation was "A."

[0054] Example 4 A vapor chamber as shown in Fig. 3 was manufactured in the same manner as in Example 3, except that the thickness of the anisotropic graphite B was 3.0 mm, the thickness of the copper plate was 0.3 mm, and the inner dimensions of the bottomed shaped part were 30 mm x 30 mm x 3.0 mm. When the temperature of the semiconductor element was evaluated using the vapor chamber, the temperature of the semiconductor element was 82°C and the evaluation was "A."

[0055] Example 5 A vapor chamber as shown in Fig. 3 was manufactured in the same manner as in Example 3, except that the plane size of anisotropic graphite B was 98 mm x 98 mm, the thickness was 5.0 mm, and the inner dimensions of the bottomed shaped part were 100 mm x 100 mm x 5.0 mm. When the temperature of the semiconductor element was evaluated using the vapor chamber, the temperature of the semiconductor element was 88°C and the evaluation was "A".

[0056] Example 6 A block of aluminum nitride was cut to have inner dimensions of 30 mm × 30 mm × 1.5 mm and an offset width of 1 mm to produce a bottomed part. A 0.013 mm thick activated silver brazing foil (model number: TKC-661, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) and anisotropic graphite B, a heat diffusion member obtained in the same manner as in Example 2, were loaded in this order into the bottomed part, and a 1 × 10 -3 The two were then heat-treated at 780°C for 30 minutes under a vacuum of 100 Pa to uniformly bond them together, producing a heat diffusion member with a 0.2 mm thick aluminum nitride coating layer formed on only one side. The heat diffusion member obtained in Production Example 3 was placed in the center of the first outer surface of the chamber body via thermal conductive grease (model number: G-775, manufactured by Shin-Etsu Chemical Co., Ltd.) so that the exposed graphite surface of the heat diffusion member faced the first outer surface of the chamber body, producing a vapor chamber as shown in Figure 3.

[0057] When the temperature of the semiconductor element was evaluated using the vapor chamber, the temperature of the semiconductor element was 91° C. and the evaluation was "B."

[0058] Example 7 A vapor chamber as shown in Fig. 3 was manufactured in the same manner as in Example 3, except that the plane size of anisotropic graphite B was 20 mm x 20 mm, the thickness was 1.0 mm, and the inner dimensions of the bottomed shaped part were 20 mm x 20 mm x 1.0 mm. When the temperature of the semiconductor element was evaluated using the vapor chamber, the temperature of the semiconductor element was 94°C and the evaluation was "B".

[0059] Example 8 A clad material was prepared in which a 0.013 mm thick activated silver solder (model number: TKC-661, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) was preliminarily formed on a 0.2 mm thick copper plate, and a bottomed part with inner dimensions of 70 mm × 70 mm × 1.5 mm and an offset width of 1 mm was manufactured by drawing using a mold. Two bottomed parts were placed opposite each other and anisotropic graphite B, the heat diffusion member, was loaded, and a 1 × 10 -3The two were then heat-treated at 780°C for 30 minutes under a vacuum of 10 Pa to uniformly bond them together, producing a heat diffusion member with a 0.2 mm thick Cu coating layer formed on its surface. The heat diffusion member obtained in Production Example 3 was placed in the center of the first outer surface of the chamber body via thermally conductive grease (model number: G-775, manufactured by Shin-Etsu Chemical Co., Ltd.) so that its main surface (70 mm x 70 mm surface) faced the first outer surface of the chamber body, producing a vapor chamber as shown in Figure 4.

[0060] When the temperature of the semiconductor element was evaluated using the vapor chamber, the temperature of the semiconductor element was 82° C. and the evaluation was "A."

[0061] Example 9 A vapor chamber as shown in FIG. 1 was produced in the same manner as in Example 1, except that anisotropic graphite B was used as the heat diffusion member.

[0062] When the temperature of the semiconductor element was evaluated using the vapor chamber, the temperature of the semiconductor element was 77° C. and the evaluation was "A."

[0063] (Comparative Example 1) When the temperature of the semiconductor element was evaluated using only the chamber body obtained in Manufacturing Example 3 as a vapor chamber without installing a heat diffusion member, the temperature of the semiconductor element was 115°C and the evaluation was "D".

[0064] (Comparative Example 2) A vapor chamber as shown in FIG. 1 was produced in the same manner as in Example 1, except that a pure copper heat diffusion member was used.

[0065] When the temperature of the semiconductor element was evaluated using the vapor chamber, the temperature of the semiconductor element was 103° C. and the evaluation was “C”.

[0066] (Comparative Example 3) A vapor chamber as shown in FIG. 1 was produced in the same manner as in Comparative Example 2, except that a heat diffusion member with a planar size of 100 mm×100 mm was used.

[0067] When the temperature of the semiconductor element was evaluated using the vapor chamber, the temperature of the semiconductor element was 100° C. and the evaluation was “C”.

[0068] Comparative Example 4 A vapor chamber as shown in FIG. 1 was produced in the same manner as in Comparative Example 3, except that a heat diffusion member having a thickness of 5.0 mm was used.

[0069] When the temperature of the semiconductor element was evaluated using the vapor chamber, the temperature of the semiconductor element was 110° C. and the evaluation was "D."

[0070] The configurations and evaluation results of the examples and comparative examples are summarized in Table 1. From Table 1, it is clear that a vapor chamber equipped with a heat diffusion member having a thermal conductivity of 500 W / mK or more is effective in suppressing the temperature rise of semiconductor elements.

[0071] [Table 1]

[0072] A vapor chamber according to one aspect of the present invention relates to the following. (I) a chamber body having a sealed space therein; A liquid material sealed in the chamber body; A vapor chamber having a heat diffusion member, the chamber body has a first outer surface, a first inner surface that is the reverse side of the first outer surface, a second outer surface, and a second inner surface that is the reverse side of the second outer surface; The sealed space is provided between the first inner surface and the second inner surface, the liquid is sealed in the sealed space, and the chamber body is provided with the heat diffusion member on the first outer surface and / or the second outer surface; A vapor chamber in which the heat diffusion member has a thermal conductivity of 500 W / mK or more in a plane direction perpendicular to the first outer surface or the second outer surface of the chamber body.

[0073] (II) The vapor chamber according to (I), wherein the heat diffusion member comprises anisotropic graphite. (III) A vapor chamber described in (II), in which the crystal orientation plane of the anisotropic graphite forms an angle of within ±10 degrees with respect to a plane perpendicular to the first outer surface or the second outer surface. (IV) The vapor chamber according to any one of (I) to (III), wherein the chamber body is made of metal. (V) A vapor chamber described in any one of (I) to (IV), in which the heat diffusion member and the chamber body are joined via a bonding layer, and the bonding layer includes at least one selected from the group consisting of solder, brazing material, diffusion bonding, and thermally conductive grease. (VI) The vapor chamber according to any one of (I) to (V), further comprising a coating layer containing either a metal or a ceramic on at least a part of the surface of the heat diffusion member. (VII) The vapor chamber according to (VI), wherein the coating layer has a thickness of 0.005 to 0.5 mm. (VIII) A vapor chamber described in (VI) or (VII), in which the coating layer has an offset region with a width of 0.5 mm or more in the surface direction at the end of the surface direction of the heat diffusion member. (IX) The vapor chamber according to any one of (I) to (VIII), wherein the thickness of the heat diffusion member is 0.5 to 10.0 mm. (X) A vapor chamber described in any one of (I) to (IX), wherein the area of ​​the heat diffusion member in the planar direction is 4 to 100% of the area of ​​the first outer surface or the second outer surface of the chamber body. (XI) A semiconductor package comprising a semiconductor element and the vapor chamber according to any one of (I) to (X), wherein the heat diffusion member and the semiconductor element are joined together. (XII) The semiconductor package according to (XI), further comprising a heat sink on the surface of the chamber body opposite to the surface on the heat diffusion member side. [Industrial Applicability]

[0074] A vapor chamber according to one aspect of the present invention is suitable for providing a semiconductor package that can suppress temperature rise of a semiconductor element. [Explanation of symbols]

[0075] (1) Chamber body (11) Liquids (2) Heat diffusion material (3) Bonding layer (4) Covering layer (5) Semiconductor elements (6) Heat sink (7) Evaporation section (8) Condenser

Claims

1. a chamber body having a sealed space therein; A liquid material sealed in the chamber body; a heat diffusion member that receives heat from the semiconductor element, the chamber body has a first outer surface, a first inner surface that is the reverse side of the first outer surface, a second outer surface, and a second inner surface that is the reverse side of the second outer surface; The sealed space is defined between the first inner surface and the second inner surface, the liquid is sealed in the sealed space, the heat diffusion member is provided on the first outer surface and / or the second outer surface of the chamber body, the thermal diffusion member has a thermal conductivity of 500 W / mK or more in a plane direction perpendicular to the first outer surface or the second outer surface of the chamber body; the heat diffusion member includes anisotropic graphite; The vapor chamber, wherein the thickness of the heat diffusion member is 1.0 to 10.0 mm.

2. The vapor chamber of claim 1 , wherein the crystal orientation plane of the anisotropic graphite forms an angle of within ±10 degrees with respect to a plane perpendicular to the first outer surface or the second outer surface.

3. The vapor chamber according to claim 1 or 2, wherein the chamber body is made of metal.

4. A vapor chamber described in any one of claims 1 to 3, wherein the heat diffusion member and the chamber body are joined via a joining layer, and the joining layer includes at least one selected from the group consisting of solder, brazing material, diffusion bonding, and thermally conductive grease.

5. The vapor chamber according to any one of claims 1 to 4, further comprising a coating layer containing either a metal or a ceramic on at least a portion of the surface of the heat diffusion member.

6. The vapor chamber according to claim 5, wherein the coating layer has a thickness of 0.005 to 0.5 mm.

7. The vapor chamber according to claim 5 or 6, wherein the coating layer has an offset region with a width of 0.5 mm or more in the surface direction at the end of the surface direction of the heat diffusion member.

8. A vapor chamber as described in any one of claims 1 to 7, wherein the surface area of ​​the heat diffusion member is 4 to 100% of the area of ​​the first outer surface or the second outer surface of the chamber body.

9. A semiconductor package comprising a semiconductor element and the vapor chamber according to any one of claims 1 to 8, wherein the heat diffusion member and the semiconductor element are joined together.

10. The semiconductor package according to claim 9 , further comprising a heat sink on a surface of the chamber body opposite to the surface on the heat diffusion member side.

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