Stacked body

Abstract

To propose a technique capable of efficiently developing a stacked body having excellent heat radiation properties as compared with a heat conductive member made of copper by using a heat conductive member and a heat generating body satisfying a predetermined relationship.SOLUTION: A heat conductive member 4 of a stacked body 1 has a rectangular shape having a length in an X direction of Lx [mm] and a length in a Y direction of Ly [mm]. A length in a Z direction of t [mm], a heat conductivity in the X direction of λx [W / (m*K)], a heat conductivity in the Y direction of λy [W / (m*K)], and a heat conductivity in the Z direction of λz [W / (m*K)], and at least one of the heat conductivity in the X direction, the heat conductivity in the Y direction, and the heat conductivity in the Z direction is different from the others. A heating element 5 has a rectangular shape having a length of Ax [mm] in the X direction and a length of Ay [mm] in the Y direction, and satisfies the following expression (1):(1 / 76050)×(Ax×λy×λz+Ay×λx×λz)+(1 / 76050^2)×λx×λy×(λz^2)×t>2×(Ax+Ay+2×t)...(1).SELECTED DRAWING: Figure 1

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 electronic components, they generate heat at high temperatures. For this reason, it is important to ensure sufficient heat dissipation when using these electronic components.

[0003] Conventionally, a laminate comprising a base substrate, an insulating layer, a circuit pattern, and an electronic component mounted on this circuit pattern has been known as a means for dissipating heat from electronic components (see, for example, Patent Documents 1 and 2). With such a laminate, heat generated by the electronic component, which is a heat-generating body, 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 for a base substrate with a water-cooling function). In other words, the circuit pattern functions as a thermally conductive member that conducts heat from the heat-generating body to the insulating layer.

[0004] Copper is commonly used as the material for circuit patterns. Copper has a high thermal conductivity (approximately 390 [W / (m·K)]) and is relatively inexpensive, making it suitable for using circuit patterns as heat conduction materials. When a material with high thermal conductivity like copper is used as a heat conduction material, heat from the heating element is easily transferred to the insulating layer, and the heat is diffused in the surface direction, increasing the heat transfer area, which allows heat to be conducted efficiently to the insulating layer and 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. 2023-40253 [Patent Document 3] Japanese Patent Publication No. 2021-197534 [Patent Document 4] Japanese Patent Publication No. 2021-150358 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, however, there has been a demand for even higher heat dissipation than when a thermally conductive member made of copper is used.

[0007] Conventionally, laminates using vapor chambers have been known as being able to improve heat dissipation compared to copper thermal conductive members. Patent Document 3 shows a laminate in which a vapor chamber that functions as a circuit for an electronic component is provided between an insulating layer and the electronic component. Note that vapor chambers are excellent at spreading heat in the surface direction, but are inferior in heat conduction in the thickness direction compared to the surface direction, and the thermal conductivity differs between the surface direction and the thickness direction.

[0008] Furthermore, a laminate using graphite, as shown in Patent Document 4, is also known as a material that can improve heat dissipation compared to thermally conductive members made of copper. Graphite has anisotropy in thermal conductivity, and generally exhibits a lower value (approximately 7 W / (m·K)) than that of copper in the direction of low thermal conductivity, but exhibits a significantly higher value (approximately 1700 W / (m·K)) than that of copper in the direction of high thermal conductivity, making it possible to diffuse heat from a heat-generating body over a wide area in a specific direction.

[0009] On the other hand, the spread of heat in a heat conductive member has not yet been fully understood, and there are still some unclear points, particularly in the case of a heat conductive member that has anisotropy in thermal conductivity.

[0010] Furthermore, in order for the thermal conductive member to effectively spread the heat from the heat-generating body, the size of the thermal conductive member must be larger than that of the heat-generating body, but as the size of the thermal conductive member increases, the laminate also becomes larger. However, the relationship between the function of diffusing and conducting heat in the thermal conductive member and the size of the member is not yet clear, not only for those that exhibit anisotropic thermal conductivity but also for those that exhibit isotropic thermal conductivity.

[0011] As such, the mechanism by which heat is spread by the thermally conductive member in the laminate has not yet been fully understood, and therefore, in order to meet the demand for even higher heat dissipation properties of the laminate than when a copper thermally conductive member is used, repeated trial and error is being conducted in the development of laminate products.

[0012] In view of these points, the present invention aims to provide a technology that understands the mechanism by which heat is spread by a thermal conductive member, thereby enabling the development of a laminate that has superior heat dissipation properties compared to copper thermal conductive members more efficiently than before. [Means for solving the problem]

[0013] The present invention provides a laminate including a base substrate, an insulating layer provided on a front side of the base substrate, a heat conduction member provided on the front side of the insulating layer, and a heating element provided on the front side of the heat conduction member, wherein, when a surface of the heat conduction member extends parallel to an XY plane in an XYZ orthogonal coordinate system, the heat conduction member has a rectangular shape with a length in the X direction of Lx [mm] and a length in the Y direction of Ly [mm] as viewed from the Z direction, and a length in the Z direction of t [mm], and has a thermal conductivity in the X direction of λx [W / (m·K)], a thermal conductivity in the Y direction of λy [W / (m·K)], and a thermal conductivity in the Z direction of λz [W / (m·K)], at least one of the thermal conductivities in the X direction, the Y direction, and the Z direction is different from the others, and the heating element has a rectangular shape with a length in the X direction of Ax [mm] and a length in the Y direction of Ay [mm] as viewed from the Z direction, and satisfies the following formula (1). (1 / 76050)×(Ax×λy×λz+Ay×λx×λz)+(1 / 76050^2)×λx×λy×(λz^2)×t>2×(Ax+Ay+2×t)...(1)

[0014] In the above-described laminate, when the distance from the first X-direction edge of the opposing heat conduction member to the first X-direction edge of the heat generating element is X1 [mm], the distance from the second X-direction edge of the opposing heat conduction member to the second X-direction edge of the heat generating element is X2 [mm], the distance from the first Y-direction edge of the opposing heat conduction member to the first Y-direction edge of the heat generating element is Y1 [mm], and the distance from the second Y-direction edge of the opposing heat conduction member to the second Y-direction edge of the heat generating element is Y2 [mm], it is preferable that the following (2) to (5) be further satisfied. X1≧X2 (2) X2≧10 (3) Y1 ≥ Y2 (4) Y2 ≥ 10 (5)

[0015] The present invention also provides a laminate comprising a base substrate, an insulating layer provided on a front side of the base substrate, a heat conduction member provided on the front side of the insulating layer, and a heating element provided on the front side of the heat conduction member, wherein, in a state in which a surface of the heat conduction member extends parallel to an XY plane in an XYZ orthogonal coordinate system, the heat conduction member has a rectangular shape with a length in the X direction Lx [mm] and a length in the Y direction Ly [mm] when viewed from the Z direction, and a length in the Z direction t [mm], and a thermal conductivity in the X direction λx [W / (m K)], a thermal conductivity in the Y direction λy [W / (m K)], and a thermal conductivity in the Z direction λz [W / (m K)], at least one of the thermal conductivity in the X direction, the thermal conductivity in the Y direction, and the thermal conductivity in the Z direction is different from the others, and the heating element has a rectangular shape with a length in the X direction Ax [mm] and a length in the Y direction Ay [mm] when viewed from the Z direction, When the distance from the first X-direction edge of the opposing heat conduction member to the first X-direction edge of the heat generating element is X1 [mm], the distance from the second X-direction edge of the opposing heat conduction member to the second X-direction edge of the heat generating element is X2 [mm], the distance from the first Y-direction edge of the opposing heat conduction member to the first Y-direction edge of the heat generating element is Y1 [mm], and the distance from the second Y-direction edge of the opposing heat conduction member to the second Y-direction edge of the heat generating element is Y2 [mm], the laminate satisfies the following formulas (6) to (10). Lx×Ly≧Ax×Ay+(1 / 76050)×(Ax×λy×λz+Ay×λx×λz)×t+(1 / 76050^2)×λx×λy×(λz^2)×(t^2)...(6) X1≧X2 (7) X2≧10 (8) Y1 ≥ Y2 (9) Y2≧10 (10)

[0016] The present invention also provides a laminate comprising a base substrate, an insulating layer provided on a front side of the base substrate, a heat conduction member provided on the front side of the insulating layer, and a heating element provided on the front side of the heat conduction member, wherein, in a state where a surface of the heat conduction member extends parallel to an XY plane in an XYZ orthogonal coordinate system, the heat conduction member has a rectangular shape with a length in the X direction Lx [mm] and a length in the Y direction Ly [mm] as viewed from the Z direction, and the length in the Z direction is t [mm], and the thermal conductivity in the X direction, the thermal conductivity in the Y direction, and the thermal conductivity in the Z direction are all λ [W / (m·K)], and the heating element has a thickness of 100 μm from the Z direction. When viewed from these viewpoints, the laminate has a rectangular shape with a length in the X direction of Ax [mm] and a length in the Y direction of Ay [mm], and when the distance from the first X-direction edge of the opposing heat conduction member to the first X-direction edge of the heat generating element is X1 [mm], the distance from the second X-direction edge of the opposing heat conduction member to the second X-direction edge of the heat generating element is X2 [mm], the distance from the first Y-direction edge of the opposing heat conduction member to the first Y-direction edge of the heat generating element is Y1 [mm], and the distance from the second Y-direction edge of the opposing heat conduction member to the second Y-direction edge of the heat generating element is Y2 [mm], the laminate satisfies the following formulas (11) to (15). Lx×Ly≧Ax×Ay+(1 / 76050)×(Ax+Ay)×(λ^2)×t+(1 / 76050^2)×(λ^4)×(t^2)...(11) X1 ≥ X2 (12) X2≧10 (13) Y1 ≥ Y2 (14) Y2 ≥ 10 (15) [Effects of the Invention]

[0017] According to the laminate of the present invention, by using a thermal conduction member and a heating element that satisfy the above-mentioned relationship, it is possible to develop a laminate that has superior heat dissipation properties compared to thermal conduction members made of copper more efficiently than before. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a side view of a laminate according to an embodiment of the present invention; [Figure 2] FIG. 2 is a plan view of the heat conducting member and the electronic component shown in FIG. [Figure 3A] FIG. 10 is a perspective view showing a modified example of the heat conduction member. [Figure 3B] 3B is a side view of a stack using the heat conductive member shown in FIG. 3A. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] 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.

[0020] Fig. 1 is a side view of a laminate 1 of this embodiment (a view facing the XZ plane in an XYZ Cartesian coordinate system), and Fig. 2 is a front view of the laminate 1 (a view facing the YY plane in an XYZ Cartesian coordinate system). The laminate 1 includes a base substrate 2, an insulating layer 3 laminated on the front side of the base substrate 2, a heat conductive member 4 laminated on the front side of the insulating layer 3, and an electronic component 5 laminated on the front side of the heat conductive member 4.

[0021] 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.

[0022] 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.

[0023] 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).

[0024] 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.

[0025] The heat conduction member 4 is plate-shaped and has an outer shape that is rectangular in plan view (rectangular or square in plan view). In this embodiment, the heat conduction member 4 is located in the center of the insulating layer 3 and covers a portion of the surface of the insulating layer 3. The heat conduction member 4 may also cover the entire surface of the insulating layer 3. The heat conduction member 4 has the function of conducting heat generated by the electronic component 5 to the insulating layer 3 while diffusing it in the planar direction, and is particularly superior in this function to a heat conduction member 4 made of copper alone. Furthermore, the thermal conductivity of the heat conduction member 4 is either anisotropic, meaning that it is different in at least one of the X, Y, and Z directions, as described below, or is isotropic, meaning that it is equal in all of the X, Y, and Z directions.

[0026] Examples of heat-conducting members 4 that exhibit anisotropic thermal conductivity include graphite members and vapor chambers. To configure the heat-conducting member 4 as a vapor chamber, a space is provided inside the heat-conducting member 4. The space contains a working fluid that evaporates when heated, dissipates heat, and condenses. A wick is provided in the space, through which the working fluid permeates, generating capillary force. The outer shell of the heat-conducting member 4 is made of a material with high thermal conductivity (e.g., copper or aluminum). This configuration evaporates the working fluid due to heat from the electronic component 5 mounted on the front side of the vapor chamber. The evaporated working fluid moves within the space, diffusing heat. The diffused vapor 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 component 5 mounted on the front side of the vapor chamber by capillary force. This repeated evaporation and condensation of the working fluid effectively diffuses heat from the electronic component 5 along the surface of the vapor chamber.

[0027] An example of the heat conducting member 4 exhibiting isotropic thermal conductivity is a plate-shaped member made of silver.

[0028] The heat conduction member 4 may be a member formed from a single material (for example, a plate-shaped member made of graphite or a plate-shaped member made of silver), or may be a member made from a composite of two or more materials (for example, a member in which a copper layer and a graphite layer are laminated).

[0029] When the heat conductive member 4 is conductive, the external device and the electronic component 5 may be electrically connected to the heat conductive member 4. In this case, the heat conductive member 4 functions as a part of a circuit connecting the external device and the electronic component 5.

[0030] 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, which is fixed to the thermally conductive member 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 thermally conductive member 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 electrical external 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.

[0031] In this embodiment, the electronic component 5 is provided relative to the heat conduction member 4 in a plan view as shown in FIG. 2 . As shown in the figure, the heat conduction member 4 has an opposing first X-direction edge 41 and a second X-direction edge 42 extending in the Y-direction, and an opposing first Y-direction edge 43 and a second Y-direction edge 44 extending in 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 in the Y-direction, and an opposing first Y-direction edge 53 and a second Y-direction edge 54 extending in the X-direction. The electronic component 5 is provided on the heat conduction member 4 such that the first X-direction edge 41 of the heat conduction member 4 faces the first X-direction edge 51 of the electronic component 5, and the first Y-direction edge 43 of the heat conduction member 4 faces the first Y-direction edge 53 of the electronic component 5.

[0032] Here, as shown in FIG. 2, the length of the heat conduction member 4 in the X direction (the length from the first X-direction edge 41 of the heat conduction member 4 to the second X-direction edge 42 of the heat conduction member 4) is defined as Lx [mm], the length of the heat conduction member 4 in the Y direction (the length from the first Y-direction edge 43 of the heat conduction member 4 to the second Y-direction edge 44 of the heat conduction member 4) is defined as Ly [mm], and the thickness of the heat conduction member 4 (the length in the Z direction) is defined as t [mm] as shown in FIG. 1. The distance from the first X-direction edge 41 of the heat conduction member 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 heat conduction member 4 is defined as X2 [mm], the distance from the first Y-direction edge 43 of the heat conduction member 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 heat conduction member 4 is defined as Y2 [mm].

[0033] In the case where a heat conduction member 4 exhibiting anisotropy in thermal conductivity is used, the thermal conductivity in the X direction is λx [W / (m·K)], the thermal conductivity in the Y direction is λy [W / (m·K)], and the thermal conductivity in the Z direction is λz [W / (m·K)]. In this specification and the like, the heat conduction member 4 exhibiting anisotropy in thermal conductivity means that at least one of the thermal conductivity λx in the X direction, the thermal conductivity λy in the Y direction, and the thermal conductivity λz in the Z direction is different from the others.

[0034] When a heat conductive member 4 exhibiting isotropic thermal conductivity is used, the thermal conductivity in the X direction, the thermal conductivity in the Y direction, and the thermal conductivity in the Z direction are all assumed to be λ [W / (m·K)].

[0035] As shown in FIG. 2, the length of electronic component 5 in the X direction (the length from first X-direction edge 51 to second X-direction edge 52 of electronic component 5) is defined as Ax [mm], and the length of electronic component 5 in the Y direction (the length from first Y-direction edge 53 to second Y-direction edge 54 of electronic component 5) is defined as Ay [mm].

[0036] The inventors of the present application conducted extensive studies using actual samples of such laminate 1 and simulations using a model of laminate 1, and found that, in order to obtain sufficient heat dissipation for heat generated in electronic component 5 compared to a copper heat conduction member 4, it is important that the heat spread in the planar direction when heat from electronic component 5 is conducted by heat conduction member 4 to insulating layer 3 is greater than when copper is used. Further studies revealed that sufficient heat dissipation can be obtained when the heat transfer area at the interface between heat conduction member 4 and insulating layer 3 is larger than that of a copper heat conduction member 4.

[0037] The above findings will be explained with reference to FIGS. 1 and 2. The dashed lines in FIG. 1 indicate the spread of heat when heat from electronic components 5 is conducted to insulating layer 3 when heat conduction member 4 is made solely of copper. When heat conduction member 4 is made solely of copper, the thermal conductivity of copper is isotropic (thermal conductivity is equal in the X, Y, and Z directions). Therefore, heat from electronic components 5 is thought to be conducted through heat conduction member 4 while spreading at a 45-degree angle with respect to the Z direction. That is, the area of ​​heat conduction member 4 surrounded by the upper solid line, the lower solid line, and the two dashed lines in FIG. 1 forms a trapezoid, and the length of the lower side of this trapezoid in the X direction is Ax+2×t. The length of the lower side of this trapezoid in the Y direction is Ay+2×t, as shown in FIG. 2. Therefore, in this case, when a copper heat conduction member 4 is used, the heat transfer area at the boundary between the heat conduction member 4 and the insulating layer 3 (the area surrounded by the dashed line in Figure 2) is defined as (Ax + 2 × t) × (Ay + 2 × t).

[0038] In contrast, when a laminate 1 using a thermally conductive member 4 exhibiting anisotropic thermal conductivity (at least one of the thermal conductivity in the X direction, the thermal conductivity in the Y direction, and the thermal conductivity in the Z direction is different from the others) was examined, it was found that the spread of heat when heat from electronic components 5 is conducted to insulating layer 3 can be considered based on the thermal conductivity of copper, 390 [W / (m·K)], and that the spread of heat is affected by both the thermal conductivity in the planar direction and the thermal conductivity in the thickness direction of the thermally conductive member 4. It was also found that in this case, the heat transfer area at the boundary between the thermal conductive member 4 and the insulating layer 3 is defined by (Ax + 2 × (λx / 390) × (λz / 390) × t) × (Ay + 2 × (λy / 390) × (λz / 390) × t), where the thermal conductivity of the thermal conductive member 4 in the X direction is λx [W / (m K)], the thermal conductivity in the Y direction is λy [W / (m K)], and the thermal conductivity in the Z direction is λz [W / (m K)]. In other words, it was found that for a laminate 1 using a thermal conductive member 4 exhibiting anisotropic thermal conductivity, in order to obtain superior heat dissipation performance for heat generated in the electronic component 5 compared to when copper is used as the thermal conductive member 4, it is necessary to satisfy the following formula (1a): (Ax+2×(λx / 390)×(λz / 390)×t)×(Ay+2×(λy / 390)×(λz / 390)×t)>(Ax+2×t)×(Ay+2×t)...(1a)

[0039] The above formula (1a) is defined as the following formula (1): Therefore, by using the following formula (1), it is possible to efficiently develop a laminate 1 that has superior heat dissipation properties compared to a thermally conductive member made of copper. (1 / 76050)×(Ax×λy×λz+Ay×λx×λz)+(1 / 76050^2)×λx×λy×(λz^2)×t>2×(Ax+Ay+2×t)...(1)

[0040] If the electronic component 5 is disposed near the end of the heat conduction member 4, the heat from the electronic component 5 will be conducted to the insulating layer 3 without being sufficiently spread by the heat conduction member 4. Further investigation into this point revealed that when the electronic component 5 is disposed offset relative to the heat conduction member 4 in a planar view (assuming that the electronic component 5 is disposed near the second X-direction edge 42 and the second Y-direction edge 44 of the heat conduction member 4 as shown in FIG. 2 ), if the distances in the X and Y directions from the heat conduction member 4 to the electronic component 5 at the closest point are set to 10 mm or more while satisfying formula (1), the heat from the electronic component 5 will be sufficiently spread by the heat conduction member 4 and conducted to the insulating layer 3. In other words, it is preferable to satisfy the above formula (1) and the following formulas (2) to (5). X1≧X2 (2) X2≧10 (3) Y1 ≥ Y2 (4) Y2 ≥ 10 (5)

[0041] If the size of the heat conduction member 4 is small relative to the heat transfer area at the boundary between the heat conduction member 4 and the insulating layer 3, the heat from the electronic component 5 will reach the edge of the heat conduction member 4 before being transferred to the insulating layer 3, and the heat spreading function of the heat conduction member 4 will not be fully utilized. Even in this case, if the electronic component 5 is arranged near the edge of the heat conduction member 4 in a planar view, the heat from the electronic component 5 will be conducted to the insulating layer 3 without being sufficiently spread by the heat conduction member 4. In light of this, we have extensively studied the relationship between the size and arrangement of the heat conduction member 4 and the electronic component 5 for the laminate 1 using the heat conduction member 4 exhibiting anisotropic thermal conductivity as described above. As a result, we have found that the size of the heat conduction member 4 is preferably equal to or larger than the heat transfer area at the boundary between the heat conduction member 4 and the insulating layer 3, and that satisfying the following formula (6a) is effective. Lx×Ly≧(Ax+2×(λx / 390)×(λz / 390)×t)×(Ay+2×(λy / 390)×(λz / 390)×t)...(6a)

[0042] The above equation (6a) is defined as the following equation (6): Lx×Ly≧Ax×Ay+(1 / 76050)×(Ax×λy×λz+Ay×λx×λz)×t+(1 / 76050^2)×λx×λy×(λz^2)×(t^2)...(6)

[0043] It has also been found that when the above formula (6) is satisfied, it is effective to arrange electronic component 5 relative to heat conductive member 4 in the state shown in FIG. 2 so that the following formulas (7) to (10) are satisfied. X1≧X2 (7) X2≧10 (8) Y1 ≥ Y2 (9) Y2≧10 (10)

[0044] Even when the thermally conductive member 4 is a member made of multiple laminated materials, the spread of heat when it is conducted from the electronic component 5 to the insulating layer 3 is considered based on the thermal conductivity of copper, 390 [W / (m K)], as described above, and is affected by both the thermal conductivity in the planar direction and the thermal conductivity in the thickness direction of the thermally conductive member 4. This point will be explained with reference to Figures 3A and 3B.

[0045] 3A and 3B is a laminated member formed by stacking a first portion 4a and a second portion 4b. The lengths of the first portion 4a and the second portion 4b in the X direction are both Lx [mm] and Ly [mm], respectively. The length of the first portion 4a in the Z direction is t1 [mm], and the length of the second portion 4b in the Z direction is t2 [mm]. The thermal conductivity of the first portion 4a in the X direction is λ1x [W / (m·K)], the thermal conductivity of the Y direction is λ1y [W / (m·K)], and the thermal conductivity of the Z direction is λ1z [W / (m·K)]. The thermal conductivity of the second portion 4b in the X direction is λ2x [W / (m·K)], the thermal conductivity of the Y direction is λ2y [W / (m·K)], and the thermal conductivity of the Z direction is λ2z [W / (m·K)].

[0046] When such a thermally conductive member 4 is used, as shown in FIG. 3B , heat from the electronic component 5 spreads in the X direction to a length L1x [mm] at the boundary between the first portion 4a and the second portion 4b, and to a length L2x [mm] at the boundary between the second portion 4b and the insulating layer 3. Although not shown, the heat from the electronic component 5 spreads in the Y direction to a length L1y [mm] at the boundary between the first portion 4a and the second portion 4b, and to a length L2y [mm] at the boundary between the second portion 4b and the insulating layer 3. In this case, the lengths L1x, L2x, L1y, and L2y are as follows: It has been found that the above-mentioned formulas (1a) and (6a) can be expressed as the following formulas (1b) and (6b), respectively. In other words, by using the formulas in which formulas (1a) and (6a) are replaced with formulas (1b) and (6b), it is possible to efficiently develop a laminate 1 that has superior heat dissipation properties compared to a thermal conduction member made of copper, even when the thermal conduction member 4 is a member made by stacking multiple materials. L1x=Ax+2×(λ1x / 390)×(λ1z / 390)×t1 L2x=L1x+2×(λ2x / 390)×(λ2z / 390)×t2 L1y=Ay+2×(λ1y / 390)×(λ1z / 390)×t1 L2y=L1y+2×(λ2y / 390)×(λ2z / 390)×t2 (L1x+2×(λ2x / 390)×(λ2z / 390)×t2)×(L1y+2×(λ2y / 390)×(λ2z / 390)×t2)>(Ax+2×(t1+t2))×(Ay+2×(t1+t2))...(1b) Lx×Ly≧(L1x+2×(λ2x / 390)×(λ2z / 390)×t2)×(L1y+2×(λ2y / 390)×(λ2z / 390)×t2)...(6b)

[0047] 3A and 3B is configured with two layers, a first portion 4a and a second portion 4b, but even if the thermal conductive member 4 has three or more layers, it is possible to calculate formulas similar to formulas (1a) and (6b) in the same manner as above. That is, when the thermal conductive member 4 has n layers (n is an integer of 2 or more), it is possible to calculate formulas similar to formulas (1a) and (6b) by assuming that the above L2x and L2y become the following Lnx and Lny. Lnx=L(n-1)x+2×(λnx / 390)×(λnz / 390)×tn Lny=L(n-1)y+2×(λny / 390)×(λnz / 390)×tn

[0048] Furthermore, the inventors of the present application also studied the relationship between the size and arrangement of the heat conductive member 4 and the electronic component 5 for the laminate 1 using a heat conductive member 4 exhibiting isotropic thermal conductivity (as described above, the heat conductivity in the X direction, the Y direction, and the Z direction are all equal, λ [W / (m K)]). In this case as well, it was found that the size of the heat conductive member 4 is preferably equal to or greater than the heat transfer area at the boundary between the heat conductive member 4 and the insulating layer 3, and that satisfying the following formula (11a) is effective. Lx×Ly≧(Ax+2×((λ / 390)^2)×t)×(Ay+2×((λ / 390)^2)×t)...(11a)

[0049] The above equation (11a) is defined as the following equation (11). Lx×Ly≧Ax×Ay+(1 / 76050)×(Ax+Ay)×(λ^2)×t+(1 / 76050^2)×(λ^4)×(t^2)...(11)

[0050] It has also been found that when the above formula (11) is satisfied, it is effective to arrange electronic component 5 relative to heat conductive member 4 in the state shown in FIG. 2 so that the following formulas (12) to (15) are satisfied. X1 ≥ X2 (12) X2≧10 (13) Y1 ≥ Y2 (14) Y2 ≥ 10 (15)

[0051] Some of the results of the above-mentioned study are shown below. Tables 1 to 4 below show the results of the study on the laminate 1 shown in FIGS. 1 and 2, where ⊚ indicates particularly superior heat dissipation compared to a copper heat conduction member, ◯ indicates excellent heat dissipation, Δ indicates slightly inferior heat dissipation, and × indicates inferior heat dissipation. Tables 1 and 2 show the results for formulas (1) to (5), Table 3 shows the results for formulas (6) to (10), and Table 4 shows the results for formulas (11) to (15). Examples 1 to 7, 11, 13 to 15, and Comparative Examples 1 and 2 show the results when graphite was used as the heat conduction member 4, Examples 8 to 10, and 12 show the results when a vapor chamber was used as the heat conduction member 4, Examples 16 to 19 show the results when a silver heat conduction member 4 was used, and Comparative Example 3 shows the results when an aluminum heat conduction member 4 was used.

[0052] [Table 1]

[0053] [Table 2]

[0054] [Table 3]

[0055] [Table 4]

[0056] As is clear from a comparison between Examples 1 to 10 and Comparative Example 1, when the heat conductive member 4 exhibiting anisotropic thermal conductivity satisfies the above formula (1), the heat dissipation properties of the laminate 1 are superior to those of a copper heat conductive member. In particular, when the formulas (2) to (5) are satisfied (Examples 1 to 4, 6, 8, and 9), the heat dissipation properties of the laminate 1 are particularly superior. Furthermore, as is clear from a comparison of Examples 11 to 15 with Comparative Example 2, when the thermal conductivity of the heat conductive member 4 exhibits anisotropy and satisfies the above formula (6), the heat dissipation properties of the laminate 1 are superior to those of a heat conductive member made of copper. Furthermore, as is clear from a comparison of Examples 16 to 19 with Comparative Example 3, when the thermal conductivity of the heat conductive member 4 is isotropic and satisfies the above formula (11), the heat dissipation properties of the laminate 1 are superior to those of a heat conductive member made of copper.

[0057] Although one embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and various modifications and alterations are possible within the spirit and scope of the present invention as set forth in the claims unless otherwise specifically limited in the above description. Furthermore, the effects of the above embodiment are merely examples of the effects resulting from the present invention, and do not mean that the effects of the present invention are limited to the above effects.

[0058] For example, in the laminate 1 described above, the electronic component 5 is disposed in the center of the heat conduction member 4 in a planar view as shown in FIG. 2. However, even if the electronic component 5 is disposed at a position shifted from the center of the heat conduction member 4 in a planar view, the present invention is still encompassed as long as the formula described in this specification is satisfied. [Explanation of symbols]

[0059] 1: Laminate 2: Base board 3: Insulation layer 4: Heat conduction material 5: Electronic components (heat generating elements)

Claims

1. A laminate including a base substrate, an insulating layer provided on a front side of the base substrate, a heat conducting member provided on the front side of the insulating layer, and a heating element provided on the front side of the heat conducting member, In a state where the surface of the heat conduction member extends parallel to the XY plane in an XYZ orthogonal coordinate system, the heat conduction member has a rectangular shape with a length in the X direction of Lx [mm] and a length in the Y direction of Ly [mm] when viewed from the Z direction, and a length in the Z direction of t [mm], the thermal conductivity in the X direction is λx [W / (m K)], the thermal conductivity in the Y direction is λy [W / (m K)], and the thermal conductivity in the Z direction is λz [W / (m K)], and at least one of the thermal conductivity in the X direction, the thermal conductivity in the Y direction, and the thermal conductivity in the Z direction is different from the others, The heating element is a laminate having a rectangular shape with a length in the X direction of Ax [mm] and a length in the Y direction of Ay [mm] when viewed from the Z direction, and satisfies the following formula (1). (1 / 76050)×(Ax×λy×λz+Ay×λx×λz)+(1 / 76050^2)×λx×λy×(λz^2)×t>2×(Ax+Ay+2×t)...(1)

2. 2. The laminate according to claim 1, wherein the distance from the first X-direction edge of the opposing heat conduction member to the first X-direction edge of the heat generating element is X1 [mm], the distance from the second X-direction edge of the opposing heat conduction member to the second X-direction edge of the heat generating element is X2 [mm], the distance from the first Y-direction edge of the opposing heat conduction member to the first Y-direction edge of the heat generating element is Y1 [mm], and the distance from the second Y-direction edge of the opposing heat conduction member to the second Y-direction edge of the heat generating element is Y2 [mm], further satisfying the following (2) to (5): X1 ≧ X2 (2) X2 ≧ 10 (3) Y1 ≧ Y2 (4) Y2 ≧ 10 (5)

3. A laminate including a base substrate, an insulating layer provided on a front side of the base substrate, a heat conducting member provided on the front side of the insulating layer, and a heating element provided on the front side of the heat conducting member, In a state where the surface of the heat conduction member extends parallel to the XY plane in an XYZ orthogonal coordinate system, the heat conduction member has a rectangular shape with a length in the X direction of Lx [mm] and a length in the Y direction of Ly [mm] when viewed from the Z direction, and a length in the Z direction of t [mm], the thermal conductivity in the X direction is λx [W / (m K)], the thermal conductivity in the Y direction is λy [W / (m K)], and the thermal conductivity in the Z direction is λz [W / (m K)], and at least one of the thermal conductivity in the X direction, the thermal conductivity in the Y direction, and the thermal conductivity in the Z direction is different from the others, The heating element has a rectangular shape with a length in the X direction of Ax [mm] and a length in the Y direction of Ay [mm] when viewed from the Z direction, When the distance from the first X-direction edge of the opposing heat conduction member to the first X-direction edge of the heat generating element is X1 [mm], the distance from the second X-direction edge of the opposing heat conduction member to the second X-direction edge of the heat generating element is X2 [mm], the distance from the first Y-direction edge of the opposing heat conduction member to the first Y-direction edge of the heat generating element is Y1 [mm], and the distance from the second Y-direction edge of the opposing heat conduction member to the second Y-direction edge of the heat generating element is Y2 [mm], a laminate that satisfies the following formulas (6) to (10). Lx×Ly≧Ax×Ay+(1 / 76050)×(Ax×λy×λz+Ay×λx×λz)×t+(1 / 76050^2)×λx×λy×(λ^2)×(t^2)...(6) X1 ≧ X2 (7) X2≧10 (8) Y1 ≧ Y2 (9) Y2 ≧ 10 (10)

4. A laminate including a base substrate, an insulating layer provided on a front side of the base substrate, a heat conducting member provided on the front side of the insulating layer, and a heating element provided on the front side of the heat conducting member, In a state where the surface of the heat conduction member extends parallel to the XY plane in an XYZ orthogonal coordinate system, the heat conduction member has a rectangular shape with a length in the X direction of Lx [mm] and a length in the Y direction of Ly [mm] when viewed from the Z direction, and a length in the Z direction of t [mm], and the thermal conductivity in the X direction, the thermal conductivity in the Y direction, and the thermal conductivity in the Z direction are all equal and are λ [W / (m K)], The heating element has a rectangular shape with a length in the X direction of Ax [mm] and a length in the Y direction of Ay [mm] when viewed from the Z direction, When the distance from the first X-direction edge of the opposing heat conduction member to the first X-direction edge of the heat generating element is X1 [mm], the distance from the second X-direction edge of the opposing heat conduction member to the second X-direction edge of the heat generating element is X2 [mm], the distance from the first Y-direction edge of the opposing heat conduction member to the first Y-direction edge of the heat generating element is Y1 [mm], and the distance from the second Y-direction edge of the opposing heat conduction member to the second Y-direction edge of the heat generating element is Y2 [mm], a laminate that satisfies the following formulas (11) to (15). Lx×Ly≧Ax×Ay+(1 / 76050)×(Ax+Ay)×(λ^2)×t+(1 / 76050^2)×(λ^4)×(t^2)...(11) X1 ≧ X2 (12) X2 ≧ 10 (13) Y1 ≧ Y2 (14) Y2 ≧ 10 (15)

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