Laminate

Abstract

To provide a laminate that can achieve adequate heat dissipation by determining the size and positional relationship between a vapor chamber and a heat generator.SOLUTION: A laminate 1 comprises a vapor chamber 4 having a rectangular shape in plan view and a heat generator 5 laminated on the front side of the vapor chamber 4 and having a rectangular shape in plan view, the laminate satisfying the following formulas (1) to (4). Vx×Vy-(Ax×Ay+20×Ax+20×Ay+400)≥0 (1), Vx+Vy-(X1+Y1+Ax+Ay+20)≥0 (2), X1≥X2 (3), and Y1≥Y2 (4).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a laminate. [Background technology]

[0002] In recent years, there has been an increase in the use of electronic components that pass large currents, such as high-brightness LEDs and power semiconductors. When a large current flows through these types of electronic components, they generate heat at high temperatures. For this reason, it is important to ensure sufficient heat dissipation when using these types of electronic components.

[0003] Conventionally, a laminate comprising a base substrate, an insulating layer, a circuit pattern, and electronic components mounted on this circuit pattern has been known as a means for dissipating heat from electronic components (see, for example, Patent Document 1). With such a laminate, heat generated in the electronic components can be conducted from the circuit pattern through the insulating layer to the base substrate, and then dissipated from the base substrate into the air (or further into water in the case of a base substrate with a water-cooling function).

[0004] Also known is a technology that uses a vapor chamber, which has a heat diffusion function, to efficiently conduct heat generated by electronic components to an insulating layer in order to improve heat dissipation. Patent Document 2 shows a laminate in which a vapor chamber that functions as a circuit for the electronic component is provided between the insulating layer and the electronic component. With this laminate, the heat from the electronic component is diffused over a wide area in the surface direction by the vapor chamber, increasing the heat transfer area, and therefore the heat is efficiently conducted to the insulating layer, thereby improving heat dissipation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-012653 [Patent Document 2] Japanese Patent Publication No. 2021-197534 Summary of the Invention [Problem to be solved by the invention]

[0006] A vapor chamber contains a working fluid that evaporates when heated, dissipates heat, and condenses, and a wick that allows the working fluid to permeate, generating capillary force. The working fluid evaporates due to heat from the heating element, transforming into a gas and moving through the vapor chamber. The gas then condenses in a lower-temperature area, dissipating heat as it returns to a liquid. This mechanism dissipates heat from the heating element. In other words, to lower the temperature of the gaseous working fluid, an area away from the heating element must be provided, making the vapor chamber larger than the heating element. Furthermore, when using a vapor chamber in a laminate such as the one described above, the vapor chamber must be made somewhat larger to increase the heat transfer area, as described above. However, in the product development of such a laminate, it is unclear how large the vapor chamber should be relative to the size of the electronic component that generates the heat to achieve sufficient heat dissipation, and repeated trial and error studies are conducted until satisfactory results are obtained.

[0007] In addition, in such laminates, the electronic component that is the heat-generating element is generally located in the center of the vapor chamber, but it is expected that the heat-generating element will be located away from the center of the vapor chamber in the future. On the other hand, there is not enough knowledge about the relationship with heat dissipation when the heat-generating element is located off-center with respect to the vapor chamber.

[0008] In view of these points, the present invention aims to provide a laminate that can achieve sufficient heat dissipation by specifying the relationship in size and position between the vapor chamber and the heating element in the laminate. [Means for solving the problem]

[0009] The present invention is a laminate comprising a vapor chamber having a rectangular shape in a plan view, and a heating element laminated on the front side of the vapor chamber and having a rectangular shape in a plan view, wherein the laminate satisfies the following formulas (1) to (4) when the opposing first X-direction edge of the vapor chamber and the second X-direction edge of the vapor chamber, and the opposing first X-direction edge of the heating element and the second X-direction edge of the heating element, extend in a direction along the Y direction in an XY Cartesian coordinate system, the opposing first Y-direction edge of the vapor chamber and the second Y-direction edge of the vapor chamber, and the opposing first Y-direction edge of the heating element and the second Y-direction edge of the heating element, extend in a direction along the X direction in an XY Cartesian coordinate system, the first X-direction edge of the vapor chamber and the first X-direction edge of the heating element face each other, and the first Y-direction edge of the vapor chamber and the first Y-direction edge of the heating element face each other. Vx × Vy - (Ax × Ay + 20 × Ax + 20 × Ay + 400) ≥ 0 (1) Vx+Vy-(X1+Y1+Ax+Ay+20)≧0···(2) X1≧X2 (3) Y1 ≥ Y2 (4) however, Vx: distance [mm] from the first edge of the vapor chamber in the X direction to the second edge of the vapor chamber in the X direction Vy: distance [mm] from the first edge of the vapor chamber in the Y direction to the second edge of the vapor chamber in the Y direction Ax: distance [mm] from the first edge of the heating element in the X direction to the second edge of the heating element in the X direction Ay: distance [mm] from the first edge of the heating element in the Y direction to the second edge of the heating element in the Y direction X1: Distance [mm] from the first edge of the vapor chamber in the X direction to the first edge of the heating element in the X direction X2: Distance [mm] from the second edge of the heating element in the X direction to the second edge of the vapor chamber in the X direction Y1: Distance [mm] from the first edge of the vapor chamber in the Y direction to the first edge of the heating element in the Y direction Y2: The distance [mm] from the second edge of the heating element in the Y direction to the second edge of the vapor chamber in the Y direction.

[0010] The laminated body preferably includes a base substrate, an insulating layer, the vapor chamber, and the heating element laminated in this order. [Effects of the Invention]

[0011] According to the laminate of the present invention, sufficient heat dissipation can be achieved by satisfying the above-mentioned relationship between the vapor chamber and the heat generating element. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional side view showing a laminate according to one embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of the vapor chamber and the electronic component shown in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the laminate according to the present invention will be described with reference to the accompanying drawings. Note that the drawings are schematic, and the thickness, width, and ratio of each part may differ from those actually implemented.

[0014] 1 is a cross-sectional side view (cross-sectional view facing the XZ plane in an XZ Cartesian coordinate system) of a laminate 1 of this embodiment. The laminate 1 includes a base substrate 2, an insulating layer 3 laminated on the front side of the base substrate 2, a vapor chamber 4 laminated on the front side of the insulating layer 3, and an electronic component 5 laminated on the front side of the vapor chamber 4.

[0015] The base substrate 2 is formed of a metal such as copper, aluminum, or iron (which may be a simple metal or an alloy). The base substrate 2 may have a single-layer structure or a multi-layer structure, and may be composed of a single member or a combination of multiple members. The base substrate 2 of this embodiment is formed into an outer shape that is rectangular in plan view (rectangular or square in plan view) without being plate-like. The shape of the base substrate 2 is not limited to that shown in the figure, and may be, for example, a shape similar to a heat sink with comb-shaped fins on the back surface.

[0016] The insulating layer 3 is formed of an insulating material and is provided so as to cover the surface of the base substrate 2. The insulating layer 3 may cover the entire surface of the base substrate 2, or may cover only a part of the surface.

[0017] The insulating layer 3 is formed from a resin composition containing a thermosetting resin. Examples of the thermosetting resin include epoxy resin, phenol resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin, and cyanate resin. One type of thermosetting resin may be used alone, or two or more types may be used in combination. The resin composition may contain, for example, a curing agent (examples include an amine-based curing agent, an imidazole-based curing agent, and a phenol-based curing agent), a curing accelerator (examples include a benzoxazine compound, a borate complex, an organic metal salt such as zinc naphthenate, cobalt naphthenate, tin octoate, cobalt octoate, cobalt bisacetylacetonate cobalt(II), and cobalt triacetylacetonate cobalt(III), a phenolic compound such as phenol, bisphenol A, and nonylphenol, a tertiary amine, a tertiary amine salt, a phosphine, and a phosphonium salt), a filler (examples include aluminum oxide, silica, aluminum nitride, boron nitride, silicon nitride, and magnesium oxide), and an additive (examples include a stabilizer, an ion scavenger, and a flexibility-imparting material).

[0018] The insulating layer 3 may be formed using a plate-shaped ceramic substrate made of, for example, silicon nitride, aluminum nitride, alumina, or the like.

[0019] The vapor chamber 4 is formed from a material with high thermal conductivity (e.g., copper or aluminum). The vapor chamber 4 of this embodiment is formed from copper, which has relatively high thermal conductivity, and is shaped like a plate with a rectangular (rectangular or square) outline in plan view. The vapor chamber 4 of this embodiment is located in the center of the insulating layer 3 and covers a portion of the surface of the insulating layer 3. The vapor chamber 4 may also cover the entire surface of the insulating layer 3. A space 4a is provided inside the vapor chamber 4. To provide the space 4a in the vapor chamber 4, for example, a plate-like member located on the surface side of the vapor chamber 4 and another member that forms a cylindrical shape with a bottom are prepared, and these members are fixed together by welding, adhesive, or the like.

[0020] The space 4a contains a working fluid that evaporates when heated, dissipates heat, and condenses through a wick that allows the working fluid to permeate, generating capillary force. This configuration allows the working fluid to evaporate due to heat from the electronic components 5 mounted on the front side of the vapor chamber 4, and the evaporated working fluid moves within the space 4a, diffusing heat. The diffused vapor then dissipates heat and condenses, returning to the working fluid. The working fluid that permeates the wick is then returned to the vicinity of the electronic components 5 mounted on the front side of the vapor chamber 4 through capillary force. This repeated evaporation and condensation of the working fluid effectively diffuses heat from the electronic components 5 along the surface of the vapor chamber 4. Although not shown, the space 4a may also be provided with reinforcing columns connecting the front and back surfaces of the vapor chamber 4.

[0021] When the vapor chamber 4 is conductive, the vapor chamber 4 may be configured so that an external device and the electronic component 5 are electrically connected to the vapor chamber 4. In this case, the vapor chamber 4 functions as part of a circuit connecting the external device and the electronic component 5.

[0022] In this embodiment, the electronic component 5 is a component through which a large current flows, such as a high-brightness LED or a power semiconductor. When a current flows through the component, the component generates heat at a high temperature and serves as a heat source. The electronic component 5 is plate-shaped and has a rectangular (rectangular or square) outline in plan view. The electronic component 5 of this embodiment has a metal portion on its underside and is fixed to the vapor chamber 4 with a bonding material (e.g., solder or a sintered material primarily composed of silver). This metal portion may function as a heat sink for dissipating heat generated by the electronic component 5 to the outside, or as an electrode for electrically connecting the electronic component 5 to the vapor chamber 4 (e.g., a drain electrode when the electronic component 5 is a power semiconductor). Although not shown, if an electrode (e.g., a gate electrode or a source electrode when the electronic component 5 is a power semiconductor) is provided on the top surface of the electronic component 5, this electrode is connected to a lead frame or the like, which serves as an external electrical terminal for connecting to an external device, via a bonding wire or the like. The electronic component 5 corresponds to the "heat generating element" in this specification.

[0023] In this embodiment, the electronic component 5 is provided relative to the vapor chamber 4 as shown in FIG. 2. Here, FIG. 2 is a plan view of the vapor chamber 4 and the electronic component 5 (a view facing the XY plane in an XY Cartesian coordinate system). As shown in the figure, the vapor chamber 4 has an opposing first X-direction edge 41 and a second X-direction edge 42 extending along the Y-direction, and an opposing first Y-direction edge 43 and a second Y-direction edge 44 extending along the X-direction. As shown in the figure, the electronic component 5 has an opposing first X-direction edge 51 and a second X-direction edge 52 extending along the Y-direction, and an opposing first Y-direction edge 53 and a second Y-direction edge 54 extending along the X-direction. The electronic component 5 is arranged in the vapor chamber 4 in a state in which the first X-direction edge 41 of the vapor chamber 4 faces the first X-direction edge 51 of the electronic component 5, and the first Y-direction edge 43 of the vapor chamber 4 faces the first Y-direction edge 53 of the electronic component 5.

[0024] Here, the distance from the first X-direction edge 41 of the vapor chamber 4 to the second X-direction edge 42 of the vapor chamber 4 is defined as Vx [mm], the distance from the first Y-direction edge 43 of the vapor chamber 4 to the second Y-direction edge 44 of the vapor chamber 4 is defined as Vy [mm], the distance from the first X-direction edge 51 of the electronic component 5 to the second X-direction edge 52 of the electronic component 5 is defined as Ax [mm], and the distance from the first Y-direction edge 53 of the electronic component 5 to the second Y-direction edge 54 of the electronic component 5 is defined as Ay [mm]. The distance from the first X-direction edge 41 of the vapor chamber 4 to the first X-direction edge 51 of the electronic component 5 is defined as X1 [mm], the distance from the second X-direction edge 52 of the electronic component 5 to the second X-direction edge 42 of the vapor chamber 4 is defined as X2 [mm], the distance from the first Y-direction edge 43 of the vapor chamber 4 to the first Y-direction edge 53 of the electronic component 5 is defined as Y1 [mm], and the distance from the second Y-direction edge 54 of the electronic component 5 to the second Y-direction edge 44 of the vapor chamber 4 is defined as Y2 [mm].

[0025] The inventors of the present application conducted extensive studies using an actual sample of such laminate 1 and a simulation using a model of laminate 1, and found that in order for laminate 1 to have sufficient heat dissipation properties against heat generated by electronic component 5, the length of at least one side of vapor chamber 4 needs to be 20 mm or more longer than the length of one side of the opposing electronic component 5. After extensive studies taking this into consideration, it was found that in order for laminate 1 to have sufficient heat dissipation properties, it is necessary to satisfy at least the following formula (1a):

[0026] Furthermore, we also conducted further studies into the heat dissipation performance when the electronic component 5 is placed offset from the vapor chamber 4, and found that when the electronic component 5 is placed near the edge of the vapor chamber 4 in plan view (assuming that the electronic component 5 is placed close to the second X-direction edge 42 and the second Y-direction edge 44 of the vapor chamber 4 as shown in FIG. 2), the sum of the distances in the X and Y directions from the vapor chamber 4 to the electronic component 5 at the closest point needs to be 20 mm or more. In other words, taking this into consideration, it is necessary to satisfy at least the following formula (2a):

[0027] Here, the above equations (1a) and (2a) are as follows: Vx×Vy≧(Ax+20)×(Ay+20)···(1a) (Vx-X1-Ax)+(Vy-Y1-Ay)≧20···(2a)

[0028] The inventors have concluded that sufficient heat dissipation properties can be obtained in the laminate 1 when the following formulas (1) to (4) are satisfied. Vx × Vy - (Ax × Ay + 20 × Ax + 20 × Ay + 400) ≥ 0 (1) Vx+Vy-(X1+Y1+Ax+Ay+20)≧0···(2) X1≧X2 (3) Y1 ≥ Y2 (4)

[0029] After further investigation, the inventors of the present application discovered that when the value of the left side of the above formula (1) is 1200 or more and the value of the left side of the above formula (2) is 20 or more, the heat dissipation properties are particularly excellent.

[0030] Some of the results of the above-mentioned study are shown below. Tables 1 and 2 below show the results of the study on the laminate 1 shown in Figures 1 and 2, where ◎ indicates particularly excellent heat dissipation, ○ indicates excellent heat dissipation, △ indicates slightly poor heat dissipation, and × indicates poor heat dissipation.

[0031] [Table 1]

[0032] [Table 2]

[0033] As is clear from a comparison between Examples 1 to 6 and Comparative Examples 1 to 6, when the above formulas (1) to (4) are satisfied, sufficient heat dissipation properties can be obtained in the laminate 1. In particular, when the value of the left side of formula (1) is 1200 or more and the value of the left side of formula (2) is 20 or more, it is found that the heat dissipation properties of the laminate 1 are particularly excellent.

[0034] Although one embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and unless otherwise limited in the above description, various modifications and changes are possible within the scope of the spirit of the present invention as set forth in the claims. Furthermore, the effects of the above embodiment are merely examples of the effects that can be obtained from the present invention, and do not mean that the effects of the present invention are limited to the above effects.

[0035] For example, in the laminate 1 described above, the insulating layer 3 is laminated on the front side of the base substrate 2, the vapor chamber 4 is laminated on the front side of the insulating layer 3, and the electronic component 5 is laminated on the front side of the vapor chamber 4. However, the layer configuration of the laminate according to the present invention is not limited to this. For example, even in the laminate 1 in which other components are provided between the base substrate 2 and the insulating layer 3 or between the insulating layer 3 and the vapor chamber 4, excellent heat dissipation properties can be obtained by satisfying formulas (1) to (4). Furthermore, in FIG. 2 , the electronic component 5 is separated from both the second X-direction edge 42 and the second Y-direction edge 44 of the vapor chamber 4. However, within the range satisfying formulas (1) to (4), the second X-direction edge 52 of the electronic component 5 may overlap the second X-direction edge 42 of the vapor chamber 4, or the second Y-direction edge 54 of the electronic component 5 may overlap the second Y-direction edge 44 of the vapor chamber 4. [Explanation of symbols]

[0036] 1: Laminate 2: Base board 3: Insulation layer 4: Vapor chamber 5: Electronic components (heat generating elements) 41: First edge of vapor chamber in X direction 42: Second edge of vapor chamber in X direction 43: First edge of vapor chamber in Y direction 44: Second edge of vapor chamber in Y direction 51: First edge of electronic component (heat generating element) in X direction 52: Second edge of electronic component (heat generating element) in X direction 53: First edge of electronic component (heat generating element) in Y direction 54: Second edge of electronic component (heat generating element) in Y direction

Claims

1. A laminate comprising a vapor chamber having a rectangular shape in a plan view and a heating element laminated on the front side of the vapor chamber and having a rectangular shape in a plan view, A laminate that satisfies the following formulas (1) to (4) when the opposing first X-direction edge of the vapor chamber and the second X-direction edge of the vapor chamber, and the opposing first X-direction edge of the heating element and the second X-direction edge of the heating element, extend in the Y direction in an XY Cartesian coordinate system, the opposing first Y-direction edge of the vapor chamber and the second Y-direction edge of the vapor chamber, and the opposing first Y-direction edge of the heating element and the second Y-direction edge of the heating element, extend in the X direction in an XY Cartesian coordinate system, the first X-direction edge of the vapor chamber and the first X-direction edge of the heating element face each other, and the first Y-direction edge of the vapor chamber and the first Y-direction edge of the heating element face each other. Vx × Vy − (Ax × Ay + 20 × Ax + 20 × Ay + 400) ≧ 0 (1) Vx+Vy-(X1+Y1+Ax+Ay+20)≧0...(2) X1 ≧ X2 (3) Y1 ≧ Y2 (4) however, Vx: distance from the first edge of the vapor chamber in the X direction to the second edge of the vapor chamber in the X direction [mm] Vy: distance from the first edge of the vapor chamber in the Y direction to the second edge of the vapor chamber in the Y direction [mm] Ax: distance from the first edge of the heating element in the X direction to the second edge of the heating element in the X direction [mm] Ay: distance from the first edge of the heating element in the Y direction to the second edge of the heating element in the Y direction [mm] X1: distance from the first edge of the vapor chamber in the X direction to the first edge of the heating element in the X direction [mm] X2: distance from the second edge of the heating element in the X direction to the second edge of the vapor chamber in the X direction [mm] Y1: distance from the first edge of the vapor chamber in the Y direction to the first edge of the heating element in the Y direction [mm] Y2: Distance from the second edge of the heating element in the Y direction to the second edge of the vapor chamber in the Y direction [mm]

2. The laminate according to claim 1 , wherein a base substrate, an insulating layer, the vapor chamber, and the heating element are laminated in this order.

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