Laminate

Abstract

To provide a laminate and a method for manufacturing the laminate that can improve the dissipation of heat generated in a chip while suppressing a decrease in durability.SOLUTION: A laminate according to the present invention includes a base portion, an insulating layer laminated on the base portion, a heat conduction member laminated on the side opposite the base portion side of the insulating layer, which is hollow and plate-shaped and has a lower thermal resistance than the insulating layer, and an electronic component laminated on the side opposite the insulating layer side of the heat conduction member, and the heat conduction member is capable of passing electricity through the electronic component.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a laminate and a method for manufacturing the laminate.

Background Art

[0002] Conventionally, a laminate in which a circuit such as copper is laminated on one side of an insulating layer and a semiconductor chip or the like is soldered on this circuit is known (see, for example, Patent Document 1). In this laminate, a heat sink or a heat dissipation plate is provided on the side opposite to the side where the semiconductor chip of the circuit is mounted in order to dissipate the heat generated from the semiconductor chip or the like.

[0003] FIG. 12 is a diagram for explaining an example of the configuration of a conventional laminate. The laminate 100 includes a heat sink 111, an insulating layer 112, a circuit 113, and a chip 114. The laminate 100 is laminated in the order of the heat sink 111, the insulating layer 112, the circuit 113, and the chip 114, and the heat generated in the chip 114 is transmitted to the heat sink 111 via the circuit 113 and the insulating layer 112. The heat sink 111 releases the transmitted heat to the outside from the end portion on the side opposite to the insulating layer 112 side.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in the laminate, in order to stabilize the operation and prevent damage to the laminate, it is desired to improve the heat dissipation property of the heat generated in the chip 114. As a means for improving the heat dissipation property, increasing the thickness of the circuit 113 can be mentioned. However, when the thickness of the circuit 113 is increased, there is a problem that the durability of the laminate is reduced due to thermal stress.

[0006] The present invention has been made in view of the above, and aims to provide a laminate and a method for manufacturing a laminate that can improve the heat dissipation of heat generated in the chip while suppressing a decrease in durability. [Means for solving the problem]

[0007] To solve the above-mentioned problems and achieve the objective, the laminate according to the present invention comprises a base portion, an insulating layer laminated on the base portion, a heat conductive member laminated on the side of the insulating layer opposite to the base portion, having a hollow plate shape and having a thermal resistance smaller than that of the insulating layer, and an electronic component laminated on the side of the heat conductive member opposite to the insulating layer, wherein the heat conductive member is capable of conducting electricity to the electronic component.

[0008] Furthermore, the laminate according to the present invention is characterized in that, in the above invention, a sealed space for holding liquid is formed in the heat conductive member.

[0009] Furthermore, the laminate according to the present invention is characterized in that the heat conductive member is a vapor chamber.

[0010] Furthermore, the laminate according to the present invention is characterized in that the base portion is a heat sink.

[0011] Furthermore, the method for manufacturing a laminate according to the present invention is characterized by comprising: a first lamination step of laminating an insulating layer on a base portion; a second lamination step of laminating a heat conductive member, which is hollow, plate-shaped, has a lower thermal resistance than the insulating layer, and is capable of conducting electricity to electronic components, on the side of the insulating layer opposite to the base portion; and a mounting step of mounting the electronic components on the side of the heat conductive member opposite to the insulating layer.

[0012] Further, in the method for manufacturing a laminate according to the present invention, in the above invention, the second lamination step laminates a plate-shaped first member constituting the bottom of the heat conductive member on the insulating layer, and joins a second member constituting a portion other than the first member of the heat conductive member to the first member.

Advantages of the Invention

[0013] According to the present invention, there is an effect that it is possible to improve the heat dissipation of heat generated in the chip while suppressing a decrease in durability.

Brief Description of the Drawings

[0014] [Figure 1] FIG. 1 is a diagram showing the configuration of a laminate according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram (part 1) showing a method for manufacturing a laminate according to an embodiment of the present invention. [Figure 3] FIG. 3 is a diagram (part 2) showing a method for manufacturing a laminate according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram (part 3) showing a method for manufacturing a laminate according to an embodiment of the present invention. [Figure 5] FIG. 5 is a diagram showing an example of the relationship between the thickness of a circuit and the thermal resistance in a conventional laminate. [Figure 6] FIG. 6 is a diagram showing an example of the temperature distribution of a laminate according to an embodiment of the present invention. [Figure 7] FIG. 7 is a diagram showing an example of the temperature distribution of a conventional laminate. [Figure 8] FIG. 8 is a diagram for explaining the stress for each material used in a circuit. [Figure 9] FIG. 9 is a diagram (part 1) showing a method for manufacturing a laminate according to Modification 1. [Figure 10] FIG. 10 is a diagram (part 2) showing a method for manufacturing a laminate according to Modification 1. [Figure 11] FIG. 11 is a diagram showing the configuration of a laminate according to Modification 2. [Figure 12]FIG. 12 is a diagram for explaining an example of the configuration of a conventional laminate. BEST MODE FOR CARRYING OUT THE INVENTION

[0015] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "embodiment") will be described with reference to the accompanying drawings. The drawings are schematic, and the relationship between the thickness and width of each part, the ratio of the thickness of each part, etc. may be different from the actual ones, and there may be parts where the dimensional relationships and ratios are different between the drawings.

[0016] (Embodiment) FIG. 1 is a diagram showing the configuration of a laminate according to an embodiment of the present invention. The laminate 1 shown in FIG. 1 includes a heat sink 11, an insulating layer 12, a vapor chamber 13, and a chip 14. The laminate 1 is formed by laminating the heat sink 11, the insulating layer 12, the vapor chamber 13, and the chip 14 in this order. The chip 14 is an electronic component such as a semiconductor chip and becomes a heat source during use.

[0017] The heat sink 11 releases the heat transmitted from one end side to the outside from the other end side. The heat sink 11 has a first part 11a having a plate shape on which the insulating layer 12 is laminated, and a second part 11b extending in a comb shape from the first part 11a toward the side opposite to the insulating layer 12 side. The heat sink 11 corresponds to the base part.

[0018] The insulating layer 12 is formed using a material having insulating properties and covers the surface of one end side of the heat sink 11. Note that if the required insulating properties of the insulating layer 12 can be ensured, it may be configured to cover only a part of the surface of one end side of the heat sink 11. , in other words, insulating material

[0019] ​The vapor chamber 13 is a hollow, plate-like structure containing a working fluid. The working fluid is, for example, water or a low-boiling-point liquid. A wick structure is formed on the inner wall of the vapor chamber 13. A columnar column 131 is also provided inside the vapor chamber 13. In the vapor chamber 13, the liquid inside vaporizes due to heat and moves through the interior. When the gas inside cools away from the heat source, it returns to a liquid state. The liquid returns to the heat source side through capillaries. In the vapor chamber 13, the heat generated by the heat source is transferred to other components by repeatedly vaporizing and liquefying the liquid as described above. The thermal properties and strength of the vapor chamber 13 can be adjusted by adjusting the thickness of the vapor chamber 13 and the number of columns 131.

[0020] Furthermore, the vapor chamber 13 is formed using, for example, a conductive material. Therefore, the vapor chamber 13 functions as a circuit for mounting the chip 14. The vapor chamber 13 is formed on the insulating layer 12 in a shape corresponding to the circuit pattern for mounting the chip 14, and allows current to flow between the chip 14 and external equipment. The vapor chamber 13 transmits electrical signals between the chip 14 and external equipment. The transmission of electrical signals includes the transmission of power supply signals. The vapor chamber 13 corresponds to a heat conductive member.

[0021] The heat sink 11 and vapor chamber 13 are formed using pure copper, heat-resistant copper, aluminum, or the like. In particular, it is preferable that the vapor chamber 13 be made of a material with high thermal conductivity and high electrical conductivity.

[0022] When the chip 14 of the laminate 1 is driven, heat is generated by the drive. The generated heat is transferred to the vapor chamber 13, and the liquid inside the vapor chamber 13 vaporizes due to the heat. The gas moves to the lower temperature side (in this case, the insulating layer 12 side), transfers heat to the insulating layer 12, then returns to a liquid state and moves back towards the heat source side by capillary action. The heat transferred to the insulating layer 12 is transferred to the first part 11a of the heat sink 11 and released to the outside from the second part 11b.

[0023] Next, the method for manufacturing the laminate 1 will be explained with reference to Figures 2 to 4. Figures 2 to 4 are diagrams showing a method for manufacturing a laminate according to one embodiment of the present invention.

[0024] First, an insulating layer 12 is formed on the heat sink 11 (see Figure 2). The insulating layer 12 is formed by transferring the materials constituting the insulating layer 12 onto the heat sink 11. Transfer can be done by pressing with a press machine. Alternatively, the insulating layer 12 may be formed by integral molding using an autoclave.

[0025] Subsequently, the vapor chamber 13 is transferred to the insulating layer 12 (see Figure 3). The vapor chamber 13 may be formed using an autoclave in addition to transfer, similar to the insulating layer 12.

[0026] After forming the vapor chamber 13 on the insulating layer 12, the chip 14 is mounted on the vapor chamber 13 (see Figure 4). Note that when forming the vapor chamber 13 using an autoclave, the vapor chamber 13 and the chip 14 can be formed simultaneously.

[0027] After mounting the chip 14, the working fluid is injected into the vapor chamber 13. Following the steps described above, the laminate 1 shown in Figure 1 is fabricated. Alternatively, the working fluid may be injected into the vapor chamber 13 before mounting the chip 14.

[0028] Next, the thermal characteristics of the laminate 1 according to this embodiment 1 and a conventional laminate (laminated 100) will be described with reference to Figures 5 to 8. Figure 5 is a diagram showing an example of the relationship between the thickness of the circuit and the thermal resistance in a conventional laminate. Here, as a configuration of a conventional laminate, the laminate 100 shown in Figure 12 will be used as an example.

[0029] In the laminate 100, the thickness of the heat sink 111 (thermal conductivity 390 W / (mK)) was set to 5.0 mm, the thickness of the insulating layer 112 (thermal conductivity 8 W / (mK)) to 0.12 mm, the thickness of the solder (thermal conductivity 49 W / (mK)) joining the circuit 113 and the chip 114 to 0.2 mm, and the thickness of the chip 14 (thermal conductivity 85 W / (mK)) to 0.1 mm. The thermal resistance was simulated by changing the thickness of the circuit 113. Note that the thickness indicates the length in the lamination direction. Furthermore, the size of each component viewed from the lamination direction was set to 30 mm x 30 mm for the heat sink 111, 20 mm x 20 mm for the insulating layer 112, 20 mm x 20 mm for the circuit 113, 10 mm x 10 mm for the solder, and 10 mm x 10 mm for the chip 114. Circuit 113 is to be made of copper (thermal conductivity 390 W / (mK)). The thermal resistance R was calculated using the following equation (1), where Tmax is the temperature of chips 14 and 114, Tmin is the temperature at the boundary between the first part 11a and the second part 11b of the heatsink 11, and Q is the heat flow rate. Here, Q = 40W. R = (Tmax - Tmin) / Q ... (1)

[0030] From the relationship between the thickness of circuit 113 and its thermal resistance, it can be seen that the thermal resistance is minimized (thermal resistance R ≈ 0.188 K / W) when the thickness is approximately 3 mm. Therefore, the thermal characteristics of a conventional laminate (laminated body 100) and laminate 1 according to this embodiment are compared, with the thickness of circuit 113 in laminate 100 set to 3.0 mm and the thickness of vapor chamber 13 (thermal conductivity 5000 W / (mK)) in laminate 1 set to 3 mm. From equation (1) above, the thermal resistance of laminate 1 is found to be 0.104 K / W.

[0031] Figure 6 shows an example of the temperature distribution of a laminate according to one embodiment of the present invention. Figure 7 shows an example of the temperature distribution of a conventional laminate. As can be seen from Figures 6 and 7, when viewed from the lamination direction, the laminate 1 according to the present invention has a lower temperature than the conventional laminate when the thickness of each component is the same.

[0032] From equation (1) above and the temperature distribution, it can be said that the laminate 1 according to the present invention efficiently transfers heat applied to the laminate (chip) to the heat sink side compared to a conventional laminate. Furthermore, if the thermal conductivity of the insulating layer 12 of the laminate 1 is 2.5 W / (mK), then from equation (1) above, the thermal resistance becomes 0.184 K / W, and a low thermal resistance can be obtained even if the thermal conductivity of the insulating layer 12 is lower than that of the insulating layer 112 of the laminate 100. Note that if the thermal conductivity of the insulating layer 112 in the laminate 100 is 100 W / (mK), then from equation (1) above, the thermal resistance becomes 0.145 K / W. In addition, the thermal conductivity can be improved by increasing the filler in the insulating layer 112, but this may reduce the insulation and adhesive strength. The laminate 1 can reduce thermal resistance to a level that is difficult to achieve with conventional structures, without increasing its thickness or increasing the amount of filler in the insulating layer 12.

[0033] Figure 8 illustrates the stress for each material used in the circuit. Figure 8 shows the stress (MPa) when the materials of heat sinks 11 and 111 are changed to copper and aluminum. The stress is determined by thermal stress analysis using Young's modulus and coefficient of thermal expansion as parameters. The Young's modulus was set to 117,000 MPa (copper) and 70,310 MPa (aluminum) for the heat sinks, 81,900 MPa for the vapor chamber 13, 117,000 MPa for the circuit 113, 40,000 MPa for the solder, and 190,000 MPa for the chip. The coefficient of thermal expansion was set to 1.65 × 10⁻⁶ for the heat sinks. -5 / K (copper), 2.38×10 -5 / K (aluminum), vapor chamber 13 1.65 × 10 -5 / K, circuit 113 1.65 × 10 -5 / K, solder 2.30×10 -5 / K, chip 3.90×10 -6 The value was set to / K. The Young's modulus and coefficient of thermal expansion of the insulating layer were determined using measured data, taking temperature dependence into consideration.

[0034] As shown in Figure 8, the stress was lower in the laminate of the present invention for both copper and aluminum materials. In particular, the stress reduction effect is significant for materials with a high coefficient of thermal expansion, such as aluminum, which is preferred for its lightweight and low-cost properties. The specific stress values ​​(MPa) are as follows. Conventional structure vs. Inventive structure Copper heatsink during cooling: 9.40 9.39 When heating 33.89 33.79 Aluminum heatsink (cooled): 173.05°C, 149.92°C When heating 196.41 184.64 From this, it can be said that the heat sink 11 of the present invention can reduce thermal stress compared to conventional laminates.

[0035] In the embodiment of the present invention described above, a vapor chamber 13 is employed in the circuit portion of the laminate 1, and the vapor chamber 13 is configured to conduct electricity to the chip and to transfer heat generated in the chip 14 to the insulating layer 12. Because the vapor chamber 13 of the laminate 1 has a hollow structure, expansion and contraction during heating and cooling are mitigated, thereby reducing thermal stress. Furthermore, the laminate 1 has a greater heat dissipation effect than conventional laminates, and temperature changes (rises) can be suppressed. According to this embodiment, by adopting the above configuration, it is possible to improve the heat dissipation of heat generated in the chip while suppressing a decrease in durability.

[0036] (Variation 1) Next, a modified example 1 of the above-described embodiment will be explained. The laminate according to modified example 1 has the same configuration as the laminate 1 according to the above-described embodiment. The manufacturing method of the laminate 1 in modified example 1 differs from that of the embodiment. The manufacturing method of the laminate 1 according to modified example 1 will be explained below with reference to Figure 9. Figures 9 and 10 are diagrams showing the manufacturing method of the laminate according to modified example 1.

[0037] First, an insulating layer 12 is formed on the heat sink 11 (see Figure 2). Then, a metal plate 13a, which constitutes part of the vapor chamber 13, is transferred onto the insulating layer 12 (see Figure 9). A wick structure is formed on the surface of this metal plate 13a opposite to the insulating layer 12 side. The metal plate 13a constitutes the bottom of the vapor chamber 13 and corresponds to the first component.

[0038] Subsequently, the component 13b that constitutes the other part of the vapor chamber 13 is joined to the metal plate 13a to create the vapor chamber 13 (see Figure 10). Component 13b is dish-shaped, with a wick structure and columns formed inside, and corresponds to the second component.

[0039] Subsequently, in the same manner as in the embodiment, the vapor chamber 13 is formed on the insulating layer 12, and then the chip 14 is mounted on the vapor chamber 13 (see Figure 4). After mounting the chip 14, working fluid is injected into the vapor chamber 13. After the process described above, the laminate 1 shown in Figure 1 is manufactured. Alternatively, the member 13b on which the chip 14 is mounted may be joined to the metal plate 13a.

[0040] The laminate 1 produced by the manufacturing process according to the modified example 1 can also obtain the same effects as the embodiment described above.

[0041] Furthermore, in the manufacturing process according to Modification 1, since the metal plate 13a is formed on the insulating layer 12 and then the member 13b is joined to form the vapor chamber 13, deformation of the internal space of the vapor chamber 13 due to loads etc. when forming the vapor chamber 13 on the insulating layer 12 can be suppressed even more reliably.

[0042] (Modification 2) Next, a modified example 2 of the above-described embodiment will be explained with reference to Figure 11. Figure 11 is a diagram showing the configuration of the laminate according to modified example 2. The laminate 1A according to modified example 2 includes a base portion 15 instead of the heat sink 11 of the laminate 1 described above. The base portion 15 is formed using, for example, metal. From the viewpoint of heat dissipation in the laminate 1A, it is preferable that the base portion 15 be formed using a material with high thermal conductivity. Examples of materials with high thermal conductivity include metals such as pure copper, heat-resistant copper, and aluminum. The manufacturing method of the laminate 1A is the same as the manufacturing method of the laminate 1. In the manufacturing method of the laminate 1, the heat sink 11 can be replaced with the base portion 15. The base portion 15 reinforces the strength of the laminate 1A. Furthermore, if the base portion 15 is formed of a material with high thermal conductivity, the heat transmitted from the insulating layer 12 can be efficiently released to the outside.

[0043] The laminated body 1A according to the modified example 2 can improve heat dissipation while suppressing a decrease in durability, compared to the conventional laminated body 100 in which the heat sink 111 is replaced with a plate-shaped base.

[0044] While embodiments for carrying out the present invention have been described so far, the present invention is not limited to the embodiments described above. For example, in the embodiments described above, an example in which a vapor chamber 13 is used as a circuit was described, but any sealed space that holds liquid inside and promotes heat exchange can be used, for example, a heat pipe or a metal plate with a heat pipe embedded in it can be used instead of the vapor chamber 13. Also, the vapor chamber 13 can be used as a circuit in places where high heat dissipation characteristics are required, and conventional copper circuits can be used in other places.

[0045] Thus, the present invention may include various embodiments not described herein, and various design modifications can be made without departing from the technical idea specified by the claims.

[0046] As described above, the laminate and method for manufacturing the laminate according to the present invention are suitable for improving the heat dissipation of heat generated in the chip while suppressing a decrease in durability. [Explanation of symbols]

[0047] 1, 1A laminate 11 Heatsink 12 Insulating layer 13. Vapor Chamber 14 chips 15 Base section

Claims

1. Insulating material, A vapor chamber in contact with the insulating material, Electronic components directly stacked in the aforementioned vapor chamber, Equipped with, The vapor chamber has a hollow structure with a wick structure formed on its inner wall and liquid contained inside. The components constituting the vapor chamber itself function as a mounting circuit for supplying power to the electronic components. The heat generated by the electronic component is configured to be transferred to the insulating material via the vapor chamber. A laminate characterized by the following features.

2. The circuit is laminated on the insulating material. The laminate according to feature 1.

3. The vapor chamber is conductive. The laminate according to feature 1.

4. The vapor chamber functions as a mounting circuit for the electronic components. The laminate according to feature 1.

5. The base part, A heat-conducting member, which is laminated on the base portion and has a hollow plate-like shape, An electronic component directly laminated on the aforementioned heat conductive member, Equipped with, The heat conducting member is a vapor chamber in which a sealed space for holding liquid is formed. The heat conductive member functions as an implementation circuit for supplying power to the electronic component. A laminate characterized by the following features.

6. The laminate according to claim 5, characterized in that the base portion is a heat sink.

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