substrate

Abstract

To provide a substrate that efficiently dissipates heat from electronic components mounted on the substrate. [Solution] The heat diffusion circuit includes a heat diffusion circuit in which heat flows by utilizing a temperature difference, and an insulator, the heat diffusion circuit includes a first pedestal and a second pedestal, the first pedestal and the second pedestal being an integrated structure with no connecting surface, the first pedestal being arranged on the side (upper side) on which the electronic components are arranged, the second pedestal being arranged on the side opposite the side on which the electronic components are arranged (lower side), the second pedestal having a structure that extends in a planar direction further than the first pedestal, and the insulator being arranged on the side of the first pedestal on which the electronic components are arranged (upper side).

Description

[Technical field]

[0001] The present invention relates to a substrate that dissipates heat generated by electronic components mounted on the substrate. [Background technology]

[0002] Patent documents 1 and 2 describe a board in which a columnar member called a copper inlay is placed inside a through hole in the board's thickness direction directly below the electronic components on the board, dissipating heat from the electronic components to the opposite side of the board. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-102506 A [Patent Document 2] JP 2005-051088 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, electronic components through which large currents flow are increasingly being mounted on substrates, and as a result, there is a demand for substrates having a structure that can efficiently dissipate heat generated by the electronic components.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a substrate that efficiently dissipates heat from electronic components mounted on the substrate, and a method for manufacturing the substrate. [Means for solving the problem]

[0006] As a result of thorough investigation into the above-mentioned problems, the inventors discovered that by adopting a structure in which the conductors extend in a planar direction on the side opposite to the side on which the electronic components are placed (lower side) rather than on the side on which the electronic components are placed (upper side), it is possible to efficiently dissipate heat generated by electronic components, and thus completed the present invention.

[0007] The substrate of the present invention (paragraph 0068 of Figures 1 and 13) for solving the above problems comprises a heat diffusion circuit 2 in which heat flows by utilizing a temperature difference, and an insulator 3, the heat diffusion circuit 2 comprises a first pedestal 21 and a second pedestal 22, the first pedestal 21 and the second pedestal 22 are an integral structure with no connecting surface, the first pedestal 21 is arranged on the side (upper side) on which the electronic component 5 is arranged, the second pedestal 22 is arranged on the side opposite to the side on which the electronic component 5 is arranged (lower side), the second pedestal 22 has a structure that extends in a planar direction further than the first pedestal 21, and the insulator 3 is arranged on the side of the first pedestal 21 on which the electronic component 5 is arranged (upper side).

[0008] According to the substrate of the present invention, the second seat 22 of the heat diffusion circuit 2 extends in the planar direction of the substrate further than the first seat 21 on the side (upper side) where the electronic components 5 are arranged, which has the effect of efficiently releasing heat to the side opposite to the side where the electronic components 5 are arranged. Furthermore, since the insulator 3 is disposed on the side (upper side) where the electronic component 5 is disposed, there is an effect that electricity can be prevented from flowing through the thermal diffusion circuit 2 even if the electronic component 5 breaks down.

[0009] Furthermore, one embodiment of the substrate of the present invention (Figure 5) is characterized in that an electrical circuit 7 that supplies electricity to the electronic component 5 is arranged in contact with the insulator 3 on the side (upper side) of the insulator 3 on which the electronic component 5 is arranged.

[0010] According to this board, the heat generated by the electronic component 5 is transferred to both the thermal diffusion circuit 2 and the electric circuit 7, thereby improving the heat dissipation effect.

[0011] Furthermore, the substrate of the present invention (FIGS. 7 and 13) includes a heat diffusion circuit 2 in which heat flows by utilizing a temperature difference, and an insulator 3, the heat diffusion circuit 2 includes a first pedestal 21 and a second pedestal 22, the first pedestal 21 and the second pedestal 22 are an integral structure having no connecting surface, the first pedestal 21 is arranged on the side (upper side) on which the electronic component 5 is arranged, the second pedestal 22 is arranged on the side opposite the side on which the electronic component 5 is arranged (lower side), the second pedestal 22 has a structure that extends in a planar direction further than the first pedestal 21, and the insulator 3 is arranged on the side (lower side) of the second pedestal 22 opposite the side on which the electronic component 5 is arranged.

[0012] According to this substrate, the second seat 22 of the heat diffusion circuit 2 extends further in the planar direction of the substrate than the first seat 21 on the side (upper side) where the electronic components 5 are arranged, which has the effect of efficiently releasing heat to the side opposite to the side where the electronic components 5 are arranged. In addition, since the insulator 3 is arranged to cover the heat diffusion circuit 2 on the side opposite to the side on which the electronic component 5 is arranged, the heat generated by the electronic component 5 can be efficiently transferred to the heat diffusion circuit 2. Furthermore, by providing the insulator 3, it is possible to prevent electricity from flowing to the lower surface side via the thermal diffusion circuit 2 even if the electronic component 5 breaks down.

[0013] Moreover, the substrate of the present invention (FIGS. 9 and 13) includes a heat diffusion circuit 2 in which heat flows by utilizing a temperature difference, an electric circuit 7 that supplies electricity to the electronic component 5, and an insulator 3, and the heat diffusion circuit 2 includes a first pedestal 21 and a second pedestal 22, the first pedestal 21 and the second pedestal 22 being an integrated structure having no connecting surface, the first pedestal 21 being arranged on the side (upper side) on which the electronic component 5 is arranged, and the second pedestal 22 being arranged on the side opposite to the side on which the electronic component 5 is arranged (lower side), the second pedestal 22 having a structure that extends in a planar direction further than the first pedestal 21, the insulator 3 being arranged on the side (lower side) of the second pedestal 22 opposite to the side on which the electronic component 5 is arranged, and the electric circuit 7 being arranged on the side of the heat diffusion circuit 2 on which the electronic component 5 is arranged (upper side).

[0014] According to this substrate, the second seat 22 of the heat diffusion circuit 2 extends further in the planar direction of the substrate than the first seat 21 on the side (upper side) where the electronic components 5 are arranged, which has the effect of efficiently releasing heat to the side opposite to the side where the electronic components 5 are arranged. Furthermore, since the insulator 3 is arranged to cover the heat diffusion circuit 2 on the side opposite to where the electronic component 5 is arranged, it is possible to prevent electricity from flowing to the back side via the heat diffusion circuit 2 even if the electronic component 5 fails. Furthermore, the heat generated by the electronic component 5 is transferred to both the thermal diffusion circuit 2 and the electric circuit 7, thereby further improving the heat dissipation effect.

[0015] Furthermore, the substrate of the present invention (FIG. 12) includes a heat diffusion circuit 2 in which heat flows by utilizing a temperature difference, an insulator 3, and an electric circuit 7 that supplies electricity to electronic component 5, and is characterized in that the heat diffusion circuit 2 is a columnar base member 28, and the electric circuit 7 is arranged in contact with one side (upper side) of the base member 28, and the insulator 3 is arranged in contact with the other side (lower side) of the base member 28.

[0016] According to this substrate, the electric circuit 7 is arranged in contact with one side of the base member 28, so that the heat generated by the electronic component 5 is transferred to both the thermal diffusion circuit 2 and the electric circuit 7, thereby improving the heat dissipation effect. Furthermore, since an insulator 3 is arranged in contact with the other side of the base member 28, even if the electronic component 5 fails, it is possible to prevent electricity from flowing to the underside via the base member 28.

[0017] Moreover, the substrate of the present invention (FIG. 15) includes one heat diffusion circuit 2G1 through which heat flows utilizing a temperature difference, the other heat diffusion circuit 2G2, a support member 81, and an insulator 3, the one heat diffusion circuit 2G1 includes one first pedestal 21G1 and one second pedestal 22G1, the one first pedestal 21G1 and the one second pedestal 22G1 have an integrated structure with no connecting surface, the one first pedestal 21G1 is disposed on the side on which the electronic component 5 is disposed, the one second pedestal 22G1 is disposed on the side opposite to the side on which the electronic component 5 is disposed, the one second pedestal 22G1 has a structure that extends further in the planar direction than the one first pedestal 21G1, and the other heat diffusion circuit 2G2 includes the other first pedestal 21G1 and the one second pedestal 22G1. the other first pedestal 21G2 is arranged on the side where the electronic component 5 is arranged and the other second pedestal 22G2 is arranged on the opposite side from the side where the electronic component 5 is arranged; the other second pedestal 22G2 has a structure extending in a planar direction further than the other first pedestal 21G2; an insulator is arranged on the side of the one second pedestal 22G1 and the other second pedestal 22G2 opposite to the side where the electronic component 5 is arranged; and a support member 81 is arranged across the one second pedestal 22G1 and the other second pedestal 22G2 via the insulator 3.

[0018] According to this substrate, the support member 81 is arranged across one second pedestal and the other second pedestal via an insulator, thereby serving to support the heat diffusion circuits 2G1 and 2G2 and having the effect of increasing the rigidity of the substrate. In addition, the support member 81 has the effect of dissipating heat from the electronic component 5 that is transmitted via the heat diffusion circuit 2G1 or the heat diffusion circuit 2G2 and the insulator 3 in this order.

[0019] Moreover, the electronic device of the present invention (FIGS. 1 and 5) includes a substrate and an electronic component 5, with an insulator 3 being interposed between the first seat 21 and the electronic component 5. According to this electronic device, since the insulator 3 is disposed between the electronic component 5, it is possible to make the electronic device capable of preventing electricity from flowing through the thermal diffusion circuit 2 even if the electronic component 5 fails.

[0020] Furthermore, the electronic device of the present invention (Figures 7, 9 and 12) is characterized in that it comprises a substrate and an electronic component 5, and there is no insulator 3 between the first base 21 and the electronic component 5 or between the base member 28 and the electronic component 5. According to this electronic device, the insulator 3 is arranged to cover the heat diffusion circuit 2 on the opposite side to the side on which the electronic component 5 is arranged, so that the electronic device can efficiently transfer heat generated by the electronic component 5 to the heat diffusion circuit 2. Effect of the Invention

[0021] According to the present invention, by using a structure in which the conductors extend in a planar direction on the side opposite to the side on which the electronic components are arranged (lower side) further than on the side on which the electronic components are arranged (upper side), heat generated by the electronic components can be dissipated efficiently. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram showing a state in which a substrate according to a first embodiment of the present invention is cut in a thickness direction. [Diagram 2] 1A to 1C are diagrams illustrating a manufacturing process of a substrate according to a first embodiment of the present invention. [Diagram 3] 1A to 1C are diagrams illustrating a manufacturing process of a substrate according to a first embodiment of the present invention. [Figure 4] 1A to 1C are diagrams illustrating a manufacturing process of a substrate according to a first embodiment of the present invention. [Diagram 5] FIG. 4 is a schematic diagram showing a state in which a substrate according to a second embodiment of the present invention is cut in the thickness direction. [Figure 6] 5A to 5C are diagrams illustrating a manufacturing process of a substrate according to a second embodiment of the present invention. [Figure 7] FIG. 11 is a schematic diagram showing a state in which a substrate according to a third embodiment of the present invention is cut in the thickness direction. [Figure 8]11A to 11C are diagrams illustrating a manufacturing process of a substrate according to a third embodiment of the present invention. [Figure 9] FIG. 11 is a schematic diagram showing a state in which a substrate according to a fourth embodiment of the present invention is cut in the thickness direction. [Figure 10] 11A to 11C are diagrams illustrating a manufacturing process of a substrate according to a fourth embodiment of the present invention. [Figure 11] 11A to 11C are diagrams illustrating a manufacturing process of a substrate according to a fourth embodiment of the present invention. [Figure 12] FIG. 13 is a schematic diagram showing a state in which a substrate according to a modified example of the fifth embodiment of the present invention is cut in a planar direction. [Figure 13] FIG. 13 is a schematic diagram showing a state in which a substrate according to a sixth embodiment of the present invention (a modified example of the first to fourth embodiments) is cut in a planar direction. [Figure 14] Fig. 1A is an enlarged schematic diagram of a heat spreading circuit of a substrate 1A according to a first embodiment of the present invention, and Fig. 1B is an enlarged schematic diagram of a heat spreading circuit of a substrate 1A according to a fifth embodiment of the present invention. [Figure 15] FIG. 13 is a schematic diagram showing a state in which a substrate according to a seventh embodiment of the present invention is cut in the thickness direction. [Figure 16] FIG. 13 is a schematic diagram showing a state in which a substrate according to a seventh embodiment of the present invention is viewed from above (the side on which electronic components are mounted) in a state in which no electronic components are mounted thereon. [Figure 17] 13A to 13C are diagrams illustrating a manufacturing process of a substrate according to a seventh embodiment of the present invention. [Figure 18] 13A to 13C are diagrams illustrating a manufacturing process of a substrate according to a seventh embodiment of the present invention. [Figure 19] 13A to 13C are diagrams illustrating a manufacturing process of a substrate according to a seventh embodiment of the present invention. [Figure 20] FIG. 17 is a perspective view showing a state in which electronic components are mounted on a board similar to the sixth embodiment (FIG. 13) of the present invention. [Figure 21] 21 is a diagram showing a partially enlarged cross section seen from the AA direction in FIG. 20. FIG. [Figure 22] FIG. 17 is a schematic diagram showing a state in which a substrate similar to the sixth embodiment (FIG. 13) of the present invention is cut in the thickness direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a substrate and a method for manufacturing the same according to the present invention will be described in detail with reference to the drawings. The substrate and the method for manufacturing the substrate described in the embodiments are merely exemplified to explain the substrate and the method for manufacturing the substrate according to the present invention, and the present invention is not limited thereto.

[0024] The substrate of the present invention has a conductor and an insulator, and the conductor, which is the circuit of the substrate (printed circuit board), and electronic components are connected so that electricity flows, thereby constituting an electronic device. The substrate of the present invention has a structure capable of efficiently dissipating heat from electronic components by including a heat diffusion circuit having a first pedestal and a second pedestal or a columnar pedestal member.

[0025] In this specification, the term "rolled conductor" refers to a conductor produced by inserting an ingot of a raw conductor between two rotating rolls, and stretching the ingot while crushing it to a desired thickness. Specifically, this refers to a rolled copper plate or a rolled aluminum plate. In the present invention, the term is not limited to a rolled plate, and a rolled copper ingot or a rolled aluminum ingot can also be used.

[0026] In addition, the electrolytic conductor in this specification is not particularly limited as long as it is a conductor produced by plating, but a specific example is copper plating.

[0027] A rolled conductor has a layered metal structure that extends in the direction of rolling (in the case of a plate-shaped conductor, in the plane (XY axis) direction of the substrate). In addition, due to the heat treatment in the process of creating the substrate, it has the characteristic of becoming a crystal grain that is close to equiaxed. On the other hand, electrolytic conductors formed by plating are characterized by a columnar metal structure in the thickness direction (Z-axis direction). The rolled conductor and the electrolytic conductor have differences in these characteristics. Therefore, even though they are made of the same material, the rolled conductor has a greater effect of improving the rigidity of the substrate than the electrolytic conductor due to the differences in these characteristics.

[0028] [First embodiment] <substrate> The structure of a substrate according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 shows an electronic device in which an electronic component 5 is mounted on a substrate 1A of the present invention. The substrate 1A of the present invention has a heat diffusion circuit 2, an insulator 3, and insulators 41 and 42 (which may be referred to as supporting insulators to distinguish them from the insulator 3). The insulators 41 and 42 extend in the same plane as the thermal diffusion circuit 2, thereby serving as plate-like structures that support the thermal diffusion circuit 2. The electronic component 5 is connected to a power source (not shown) via wiring 61 and 62, and is in a state where electricity is supplied so that the electronic component 5 can perform its functions.

[0029] <Heat diffusion circuit> The heat diffusion circuit 2 utilizes a temperature difference to allow heat to flow, and serves to receive heat generated by the electronic component 5 and dissipate the heat to the side (lower side) opposite to the side on which the electronic component 5 is placed (upper side). The heat diffusion circuit 2 has a first pedestal 21 and a second pedestal 22, and the first pedestal 21 and the second pedestal 22 are an integral structure with no connecting surface in the plate thickness direction or the planar direction. This structure makes it possible to prevent the heat diffusion circuit 2 from peeling off from the connecting surface even if heat is applied to the heat diffusion circuit 2 or the heat diffusion circuit 2 is cooled without supplying electricity to the electronic component 5, causing repeated thermal expansion.

[0030] The first seat 21 is an inlet that receives heat generated by the electronic component 5 before the second seat 22. The first seat 21 is located on the side (upper side) where the electronic component is mounted (placed), and has a structure that does not extend further in the planar direction than the second seat 22.

[0031] The second pedestal 22 receives heat from the first pedestal 21 and dissipates the heat to the side (lower side) opposite to the side of the board 1A on which the electronic components 5 are arranged. The second pedestal 22 is located on the side (lower side) opposite to the side on which the electronic components are mounted (arranged), and has a structure that is wider in the planar direction than the first pedestal 21. The lower surface side of the second pedestal 22 is exposed to the lower surface side of the board 1A. The entire periphery of the side surface of the second pedestal 22 and the entire upper surface (side surface of the first pedestal) are covered with the insulators 41 and 42, and the second pedestal 22 is not electrically connected to a circuit connected to a power source.

[0032] Although there are no particular limitations on the thickness of first pedestal 21 and the thickness of second pedestal 22 in the plate thickness direction, it is preferable that second pedestal 22 is thicker than first pedestal 21. By increasing the thickness of second pedestal 22, the volume of the conductor of heat diffusion circuit 2 is increased, and more heat generated by electronic component 5 can be received, improving the heat dissipation effect. The material of the thermal diffusion circuit 2 may be any material capable of transmitting heat and having a higher thermal conductivity than the insulators 41 and 42. Specific examples include conductors such as copper and aluminum. The thermal diffusion circuit 2 may be formed from either a rolled conductor or an electrolytic conductor formed by plating. However, it is more preferable to form the thermal diffusion circuit 2 from a rolled conductor since this improves the rigidity of the substrate 1A. Furthermore, by forming the heat diffusion circuit 2 from a rolled conductor and making the thickness of the second base 22 greater than the thickness of the first base 21, not only is the heat dissipation effect improved, but the rigidity of the board can also be further improved, which is even more preferable. Furthermore, by separately providing a heat dissipation member such as a heat sink below the second pedestal 22, it is possible to further improve the heat dissipation effect.

[0033] <Insulator> The insulator 3 is placed in contact with the upper surface of the thermal diffusion circuit 2 to prevent electricity from flowing downward through the thermal diffusion circuit 2 even if the electronic component 5 fails. The insulator 3 is not particularly limited as long as it is made of a material that can prevent electricity from flowing to the back side through the thermal diffusion circuit when the electronic component 5 fails, but examples of the material include insulating resin, insulating sheet, and ceramic material, which is an inorganic material. The insulator 3 is disposed so as to cover the entire upper side of the first pedestal 21 across an insulator 41 described later and to extend in the planar direction. Specifically, it is preferable that the thickness of the insulator 3 is smaller than the thicknesses of the insulators 41 and 42 described below. A small thickness of the insulator 3 is preferable from the viewpoint of improving the efficiency of heat dissipation from the thermal diffusion circuit 2. When an insulating sheet is used as the insulator 3, for example, one having a thickness of 100 μm or more and 200 μm or less can be used. Furthermore, when a ceramic material is used as the insulator 3, a plate-shaped ceramic material can be disposed, or a ceramic coating can be applied. In the case of ceramic coating, examples of the processing method include cold spray method and aerosol deposition method. Among these ceramic coating processing methods, the aerosol deposition method is more effective than other ceramic coating processing methods in that it allows the formation of thin ceramic films and reduces thermal resistance while maintaining insulation. The ceramic thin film has a thickness of, for example, 0.5 μm or more and 1 mm or less. Furthermore, the aerosol deposition method is particularly preferable when applied to a substrate having a heat diffusion circuit 2, since it provides higher adhesion than conventional processing methods. A board equipped with a heat spreading circuit 2 is used when it is necessary to dissipate heat generated by electronic components, and the heat is also transferred to the board itself. In that case, a board made of different materials, a conductor and an insulator, may warp due to the difference in the thermal expansion coefficient between the conductor and the insulator. From the above, it can be seen that a ceramic thin film created by the aerosol deposition method has high adhesion, which reduces the risk of peeling off even if the substrate is warped, and since its thickness can be made thin, it is highly effective in improving heat dissipation efficiency. The aerosol deposition method is a processing method in which fine particles or ultrafine particles prepared in advance by another method are mixed with gas to form an aerosol, which is then sprayed onto a substrate through a nozzle to form a coating. Examples of the aerosol deposition method include those disclosed in Japanese Patent No. 3265481 and Japanese Patent No. 3740523.

[0034] The insulators (support insulators) 41 and 42 are for supporting the thermal diffusion circuit 2 in a plate shape, and are arranged in contact with the side surfaces (planar direction) of the thermal diffusion circuit 2. The insulators 41 and 42 also play a role in maintaining a distance that prevents electricity from flowing from a circuit (not shown) arranged on the same plane as the thermal diffusion circuit 2 to the thermal diffusion circuit 2. The insulators 41 and 42 are not particularly limited in material as long as they are capable of supporting the thermal diffusion circuit 2 in a plate shape, and may be made of insulating resin, for example. The insulators 3, 41, and 42 may be made of the same material or different materials. Insulator 41 is disposed on the side surface (periphery) of first pedestal 21 and extends in the planar direction. Insulator 42 is disposed on the side surface (periphery) of second pedestal 22 and extends in the planar direction. 1, insulator 41 and insulator 42 have connection surface 43. Connection surface 43 is located at a position of the same thickness as the boundary in the plate thickness direction between first pedestal 21 and second pedestal 22. In other words, connection surface 43 is located at the same position as the surface of second pedestal 22 on the side (upper side) where electronic component 5 is placed and the lower surface of insulator 41 come into contact with each other.

[0035] When the heat diffusion circuit 2 is provided by etching a rolled conductor as shown in the manufacturing method of this embodiment described later, the first pedestal lower part 212 is wider in the planar direction and has a larger volume than the first pedestal upper part 211, as shown in A of Fig. 14. Also, the second pedestal upper part 221 is wider in the planar direction and has a larger volume than the second pedestal lower part 222. In other words, the thermal diffusion circuit 2 has a structure in which the central portion in the plate thickness direction expands in the planar direction, and a large volume of the conductor can be secured, thereby improving the heat dissipation performance.

[0036] <Electronic Components> The electronic component 5 is not particularly limited as long as it generates heat when power is supplied, and is a component from which the heat diffusion circuit 2 of the substrate 1A of the present invention removes heat. Specific examples include LEDs and power transistors. <Wiring> The wiring 61 and 62 are for supplying electricity to the electronic component 5. There are no particular limitations on the structure as long as electricity can be supplied to the electronic component 5, but in this embodiment, a case where the wiring is connected by wire bonding is illustrated. The wiring 61 and 62 are connected to a power source (not shown) and serve as a path through which electricity flows from the power source.

[0037] [Substrate manufacturing method] Next, a method for producing the substrate 1A of the present invention will be described with reference to FIGS. First, a plate-shaped rolled conductor 20 is prepared. This process is referred to as a rolled conductor preparation process.

[0038] 2(A), an etching resist 25 is provided on the surface of the rolled conductor 20. A process is performed in which a portion of one side (upper side) of the rolled conductor 20 that will become the first pedestal 21 is covered with the etching resist 25. This process is referred to as a first resist forming process. In the first resist preparation step, the entire other surface of the rolled conductor 20 may also be protected with the etching resist 25 .

[0039] Next, while covered with the etching resist 25 from the first resist preparation step, the rolled conductor 20 is etched (half etched). This step is referred to as the first etching step. Through this step, a recess 45 is formed on one side of the rolled conductor 20, and the first seat 21 is formed. Then, the etching resist 25 provided in the first resist step is removed, resulting in the state shown in FIG. 2(B). The lower surface of this recess 45 becomes the connection surface 43.

[0040] 2(C), a step of filling recess 45 on one side with insulating resin is performed. This step is referred to as a first insulating resin filling step. By this process, the insulator 41, which is the supporting insulator, is formed. After the first insulating resin filling step, one of the surfaces of the insulator 41 (insulating resin) and the first seat 21 may be subjected to a surface preparation process so that the surfaces are flat. This process is referred to as a first surface preparation process.

[0041] 3(A), a step is performed in which a portion of the other side (lower side) of the rolled conductor 20 that will become the second pedestal 22 is covered with an etching resist 26. This step is referred to as a second resist forming step. In the second resist preparation step, the entire surface of one side of the rolled conductor 20 may also be protected by the etching resist 26 .

[0042] Next, the rolled conductor 20 is etched while covered with the etching resist 26 in the second resist preparation process. This process is called the second etching process. By this process, a recess 46 is formed on the other surface of the rolled conductor 20. Then, the etching resist 26 provided in the second resist process is removed, resulting in the state shown in FIG. 3(B). The recess 46 is etched so that the back surface (lower side) of the insulator 41 is exposed. This process also forms the second pedestal 22, completing the thermal diffusion circuit 2.

[0043] Next, as shown in FIG. 3(C), a process is performed in which the recess 46 on the other side is filled with insulating resin. This process is called the second insulating resin filling process. This process forms the insulator 42, which is the supporting insulator. This process also completes the connection surface 43. After the second insulating resin filling step, the other surface of the insulator 42 (insulating resin) and the second pedestal 22 may be subjected to a surface preparation process so that the surfaces of the insulator 42 (insulating resin) and the second pedestal 22 are flat. This step is referred to as a second surface preparation step.

[0044] 4(A), an insulating sheet or ceramic material is placed so as to cover the entire upper side of the first pedestal 21, and the insulator 3 is formed. This process is called an insulator upper surface setting process. By forming the insulator 3, the substrate 1A is completed.

[0045] After that, a solder resist is provided on the upper and lower surfaces of the substrate 1A to protect the substrate surface, and a heat dissipation member such as a heat sink is provided under the second seat 22 to further improve the heat dissipation efficiency of the substrate. Then, as shown in FIG. 4(B), the electronic component 5 is placed on the insulator 3, and wiring 61 and 62 are provided by wire bonding to obtain the electronic device shown in FIG. 1. Then, electricity from a power source (not shown) flows between the wiring 61, the electronic component 5, and the wiring 62. Also, heat generated by the electronic component 5 is dissipated to the lower surface side of the substrate 1A via the insulator 3, the first seat 21, and the second seat 22.

[0046] [Second embodiment] <substrate> The structure of a substrate according to a second embodiment for carrying out the invention will be described with reference to Fig. 5. Components having the same structure as substrate 1A of the first embodiment are given the same reference numerals and will not be described. Substrate 1B of the present invention differs from substrate 1A of the first embodiment in that it includes an electric circuit 7.

[0047] Electrical Circuits The electric circuit 7 is a circuit that supplies electricity to the electronic components 5, and also has a function of cooling the electronic components 5 together with the heat diffusion circuit 2 by receiving a portion of the heat generated by the electronic components 5. The electric circuit 7 is provided so as to extend in a planar direction on the surface of the substrate 1B on the side where the electronic components 5 are disposed. The electric circuit 7 is disposed so as to be located directly below the electronic components 5 and to cover the insulator 3. The electric circuit 7 is not particularly limited as long as it can pass electricity, but it is preferable to mold it from an electrolytic conductor since it is easy to manufacture. The electric circuit 7 is disposed between the insulator 3 and the electronic component 5, and the electric circuit 7 is disposed in contact with the insulator 3 on the side (upper side) of the insulator 3 on which the electronic component 5 is disposed. Moreover, the electric circuit 7 is disposed in contact with the electronic component 5 and is connected to the electronic component 5 by a connecting member such as solder so as to supply electricity thereto.

[0048] [Substrate manufacturing method] A method for manufacturing the substrate 1B will be described with reference to Fig. 6. The method for manufacturing the substrate 1B is the same as the method for manufacturing the substrate 1A of the first embodiment of the present invention, and includes steps from the rolled conductor preparation step to the insulator upper surface installation step. In the state shown in Fig. 4(A), a conductor 70 is provided on the entire surface on the side (upper side) on which the electronic component 5 is to be disposed, as shown in Fig. 6(A). More specifically, an electrolytic conductor is provided by a plating process. This process is referred to as a conductor forming process.

[0049] 6(B), an etching resist 27 is provided on the surface of the conductor 70 so as to cover the area that will become the electric circuit 7. This step is referred to as a third resist forming step.

[0050] Next, with the etching resist 27 provided, an etching process is performed to form the electric circuit 7. This process is called the electric circuit forming process. The substrate 1B is completed by this process. After that, the etching resist 27 is removed to obtain the substrate 1B shown in FIG. 6(C). In the third resist forming step, the entire lower surface of the heat diffusion circuit 2 may also be protected with the etching resist 27.

[0051] Thereafter, like the board 1A, a solder resist is provided on the board 1B, and a heat dissipation member is provided on the underside of the second seat 22. Then, as shown in FIG. 5, the electronic component 5 is placed on the electric circuit 7, and a wiring 61 such as a wire bonding is connected to the electric circuit 7, and the wiring 62 is connected to the electronic component 5. Then, electricity from a power source (not shown) flows between the wiring 61, the electric circuit 7, the electronic component 5, and the wiring 62. In addition, heat generated by the electronic component 5 is dissipated to the underside of the board 1B via the electric circuit 7, the insulator 3, the first seat 21, and the second seat 22 in this order. In addition, a part of the heat is transferred in the planar direction of the electric circuit 7 and dissipated to the upper side of the board 1B. [Third embodiment] <substrate> The structure of a substrate according to a third embodiment for carrying out the invention will be described with reference to Fig. 7. Components having the same structure as substrate 1A of the first embodiment are given the same reference numerals, and descriptions thereof will be omitted. Substrate 1C of the present invention differs from substrate 1A of the first embodiment in that the location of insulator 3 is different, and there is no insulator 3 between first seat 21 and electronic component 5.

[0052] <Insulator> The insulator 3 is disposed for the purpose of providing insulation so that, in the event that the electronic component 5 is damaged, electricity does not flow to the lower surface side of the substrate 1C via the heat diffusion circuit. The insulator 3 is disposed so as to be in contact with the second seat 22 and to cover the entire surface (lower surface) opposite to the side on which the electronic components are disposed.

[0053] <Electronic Components> The electronic component 5 is disposed in contact with the first seat 21 of the heat diffusion circuit 2. Therefore, the substrate 1C can receive heat from the electronic component 5 more quickly than the substrate 1A in which the insulator 3 is disposed between the electronic component 5 and the first seat 21, and the heat dissipation effect is improved.

[0054] [Substrate manufacturing method] A method for manufacturing the substrate 1C will be described with reference to Fig. 8. The method for manufacturing the substrate 1C is the same as the method for manufacturing the substrate 1A of the first embodiment of the present invention, and includes steps from the rolled conductor preparation step to the second insulating resin filling step. In the state shown in Fig. 3(C), as shown in Fig. 8(A), an insulating sheet or ceramic coating is placed so as to cover the entire lower surface of the second pedestal 22, and the insulator 3 is formed. This process is called the insulator lower surface installation process. By forming the insulator 3, the substrate 1C is completed.

[0055] Thereafter, like the substrate 1A, a solder resist is provided on the substrate 1C, and a heat dissipation member is provided on the insulator 3 arranged under the second seat 22. Then, as shown in FIG. 8B, the electronic component 5 is placed on the first seat 21, and wiring 61 and 62 are provided by wire bonding to obtain the electronic device shown in FIG. 7. Then, electricity from a power source (not shown) flows between the wiring 61, the electronic component 5, and the wiring 62. Also, heat generated by the electronic component 5 is dissipated to the back side of the substrate 1C via the first seat 21, the second seat 22, and the insulator 3 in this order.

[0056] [Fourth embodiment] <substrate> The structure of a substrate according to a fourth embodiment for carrying out the invention will be described with reference to Fig. 9. Components having the same structure as substrate 1B of the second embodiment are given the same reference numerals, and description thereof will be omitted. Substrate 1D of the present invention differs from substrate 1B of the second embodiment in that the location of insulator 3 is different, there is no insulator 3 between first seat 21 and electric circuit 7, and first seat 21 and electric circuit 7 are arranged in contact with each other.

[0057] <Insulator> The insulator 3 is similar to that in the third embodiment, and is arranged for the purpose of providing insulation so that in the event that the electronic component 5 is damaged, electricity does not flow to the underside of the substrate 1D via the heat diffusion circuit 2. The insulator 3 is disposed so as to be in contact with the second seat 22 and to cover the entire surface (lower surface) opposite to the side on which the electronic component 5 is disposed. <Electronic Components> The electronic component 5 is disposed in contact with the electric circuit 7. Therefore, the board 1D can receive heat from the electronic component 5 more quickly and has an improved heat dissipation effect than the boards 1A and 1B in which the insulator 3 is disposed between the electronic component 5 and the first seat 21. In addition, since the heat spreads in the planar direction of the electric circuit 7, the heat dissipation effect is higher than that of the board 1C. In this embodiment, when electricity is supplied to the electronic component 5, an electric charge is applied to the thermal diffusion circuit 2, but in order to prevent electricity from flowing to other parts via the thermal diffusion circuit 2, an insulator 3 is disposed below the thermal diffusion circuit 2, and insulators 41 and 42 are disposed all around the side surface of the thermal diffusion circuit 2 and on the entire upper surface of the second pedestal. The thermal diffusion circuit 2 is a conductive structure to which an electric charge is applied but which is not used as a path for electricity to flow, and in the substrate 1D, such a conductive structure is provided within the circuit.

[0058] [Substrate manufacturing method] A method for manufacturing substrate 1D will be described with reference to Fig. 10. The method for manufacturing substrate 1D includes the steps from the rolled conductor preparation step to the second insulating resin filling step in the method for manufacturing substrate 1A (Fig. 3C). Thereafter, similar to the method for manufacturing substrate 1B, the conductor preparation step (Fig. 10A), the third resist preparation step (Fig. 10B), and the electric circuit preparation step (Fig. 10C) are performed. Then, similar to the method for manufacturing substrate 1C, the insulator lower surface installation step (Fig. 11A) is performed to achieve the substrate 1D. In the conductor forming step (FIG. 10A), the conductor 70 is formed across the surfaces of the insulator 41 and the first seat 21.

[0059] Thereafter, like the boards 1A to 1C, a solder resist is provided on the board 1D, and a heat dissipation member is provided on the insulator 3 arranged under the second seat 22. Then, as shown in FIG. 11B, the electronic component 5 is arranged on the electric circuit 7, and the wiring 61 such as wire bonding is connected to the electric circuit 7, and the wiring 62 is connected to the electronic component 5, thereby forming the electronic device shown in FIG. 9. Then, electricity from a power source (not shown) flows between the wiring 61, the electric circuit 7, the electronic component 5, and the wiring 62. In addition, heat generated by the electronic component 5 is dissipated to the back side of the board 1D via the electric circuit 7, the first seat 21, the second seat 22, and the insulator 3 in this order. In addition, a part of the heat is transferred in the planar direction of the electric circuit 7 and dissipated to the upper surface side of the board 1D.

[0060] [Fifth embodiment] <substrate> The structure of a substrate according to a fifth embodiment for carrying out the invention will be described with reference to Fig. 12. Components having the same structure as those of the substrate 1D of the fourth embodiment are given the same reference numerals, and description thereof will be omitted. The substrate 1E of the present invention differs from the substrate 1D of the fourth embodiment in that the shape of the heat diffusion circuit 2 is different. Also, there is no insulator 3 between the heat diffusion circuit 2 (base member 28) and the electronic component 5.

[0061] <Heat diffusion circuit> The heat diffusion circuit 2 includes a base member 28. The base member 28 is a columnar member. The base member 28 does not have a step between the upper portion (corresponding to the first base 21) and the lower portion (corresponding to the second base 22) of the thermal diffusion circuit 2 as in the first to fourth embodiments of the present invention. The surface area of ​​the upper side of the base member 28 and the surface area of ​​the lower side of the base member 28 are the same, or the surface area of ​​the lower side of the base member 28 is larger than the surface area of ​​the upper side of the base member 28. In other words, the base member 28 may be formed by inserting a cylindrical conductive member (corresponding to a copper inlay in the prior art) of the same diameter from top to bottom into a through hole provided in the thickness direction of the substrate 1E, or a cone-shaped conductive member with an upper side area smaller than the lower side area, or by arranging an integrated conductor with no connection surface by plating the through hole, or by etching a rolled conductor into an integrated columnar shape with no connection surface. However, when the base member 28 is provided by etching the rolled conductor according to the manufacturing method of the substrate shown in the manufacturing method of this embodiment described later, as shown in Fig. 14B, the base member central portion 283, which is the central portion in the plate thickness direction of the substrate 1E, can have a columnar shape that is wider in the planar direction than the upper surface of the base member upper portion 281 and the lower surface of the base member lower portion 282, and the volume of the conductor can be increased, which is preferable in terms of improving the heat dissipation effect of the heat generated by the electronic component 5. Note that the base member upper portion 281 and the base member lower portion 282 may have the same volume or different volumes.

[0062] [Substrate manufacturing method] The manufacturing method of the substrate 1E will be described below. The manufacturing method of the substrate 1E is the same as the manufacturing method of the substrate 1D, and is realized by carrying out the steps from the rolled conductor preparation step to the insulator lower surface installation step. At this time, the etching resist 25 and the etching resist 26 provided in the first resist forming step and the second resist forming step are provided so as to have the shape of the pillar member after the second etching step.

[0063] Thereafter, a solder resist is provided as in the case of the substrate 1E, and a heat dissipation member is provided on the insulator 3 arranged under the second pedestal 22. Then, the electronic component 5 is placed on the electric circuit 7, the wiring 61 is connected to the electric circuit 7 by wire bonding, and the wiring 62 is connected to the electronic component 5, thereby forming the electronic device shown in FIG. 12. Then, electricity from a power source (not shown) flows between the wiring 61, the electric circuit 7, the electronic component 5, and the wiring 62. In addition, heat generated by the electronic component 5 is dissipated to the lower surface side of the substrate 1E via the electric circuit 7, the pedestal member 28, and the insulator 3 in this order. In addition, part of the heat is transferred in the planar direction of the electric circuit 7 and dissipated to the surface side of the substrate 1E.

[0064] [Sixth embodiment] In the sixth embodiment of the present invention, modified examples of the first to fourth embodiments are illustrated. In the first to fourth embodiments, as shown in Fig. 13, another circuit 71 may be provided in the same layer as the electric circuit 7 or the electronic component 5. The other circuit 71 is disposed on the upper surface side of the second pedestal 22 with an insulator 41 interposed therebetween. In the first to fourth embodiment of the present invention, since other circuits 71 can be arranged on the upper side of the second base 22, it is possible to obtain the effect of improving the freedom of circuit design. The other circuits 71 can be realized, for example, as in the second embodiment of the present invention, by performing a conductor creation process, providing an etching resist that covers the portion that will become the other circuits 71 in a third resist creation process, and then performing an electrical circuit creation process.

[0065] 13, a lower surface side conductor 72 may be provided between the second pedestal 22 and the insulator 3 in the plate thickness direction (on the lower surface side of the second pedestal 22). In other words, the insulator 3 is disposed below the second pedestal 22. The manufacturing method for the lower-side conductor 72 can be achieved by providing a conductor 70 on the lower side of the substrate in the conductor creation process, providing an etching resist that covers the portion that will become the lower-side conductor 72 in the third resist creation process, and etching the lower surface of the substrate in the electrical circuit creation process. Moreover, it is preferable that the lower-surface-side conductor 72 is in a state in which it spreads out in the planar direction from the second pedestal 22, and has a larger area than the second pedestal 22. This further improves the effect of dissipating heat from the second pedestal 22 to the outside.

[0066] In the first to fourth embodiments of the present invention, it is preferable that the electronic component 5, the insulator 3, and the heat diffusion circuit 2 are arranged in a straight line in the plate thickness direction. In other words, it is preferable in terms of efficient heat conduction that the entire bottom surface of the electronic component 5 (the surface on which the heat diffusion circuit 2 is arranged) is placed on the first seat 21 of the heat diffusion circuit 2 via the insulator 3 or is placed in contact with the first seat 21 of the heat diffusion circuit 2. However, as shown in FIG. 13, the effects of the present invention can be achieved even if electronic component 5 is positioned offset in the planar direction relative to first pedestal 21, or if the planar area of ​​first pedestal 21 is smaller than the area of ​​the bottom surface of electronic component 5.

[0067] In the second and fourth embodiments of the present invention, the wiring 61 is connected to the electric circuit 7, but as in the sixth embodiment, the wiring 61 may be connected to the electronic component 5 in FIG. 5 (second embodiment of the present invention) and FIG. 9 (fourth embodiment). In other words, the electronic device may be in a state where no electricity flows through the electric circuit 7. In this case, the electric circuit 7 does not serve as a path through which electricity flows, but serves as a circuit that dissipates heat to the upper surface.

[0068] 13, the insulator 3 may be provided between the electronic component 5 and the electric circuit 7 in the plate thickness direction. In other words, the insulator 3 may be provided on the upper side of the first seat 21 (the side on which the electronic component is placed).

[0069] When a transistor is used as the electronic component 5, the electric circuit 7 may be used as a circuit through which electricity flows (corresponding to an electric-thermal current circuit). In this case, for example, the wiring 61 may be designed to be the source, the wiring 62 to be the gate, and the electric circuit 7 to be the drain.

[0070] Fig. 20 is a perspective view of a state in which electronic component 5 is mounted on a board similar to the board shown in Fig. 13. Fig. 21 is a partially enlarged view of a cross section seen from the AA direction in Fig. 20 in a state in which the insulator of the board similar to the board shown in Fig. 13 has been removed. The difference from the embodiment of FIG. 13 is that the heat spreading circuit 2 is designed to allow a large current to flow. The large current is the current required for electronic components to operate. In the circuit of the board, there are conductors called signal lines that are used to transmit logic signals from one end of the circuit to the other end, and conductors that become circuits that supply power to electronic components. FIG. 20 illustrates an example in which the heat spreading circuit 2 is used as a circuit that supplies power to electronic components. In Figure 22, in Figures 20 and 21, a transistor is implemented as electronic component 5, and is connected to second base 22 and another circuit (a circuit connected to a power source) at a location not shown in the figure so that a large current flows via first base 21 and second base 22. The transistor serving as the electronic component 5 is designed so that the wiring 61 serves as the source, the wiring 62 serves as the gate, and the heat diffusion circuit 2 serves as the drain. When the transistor of the electronic component 5 operates, electricity is supplied to the electronic component 5 via the heat diffusion circuit 2, and the transistor generates heat. The heat is dissipated below the second pedestal via the heat diffusion circuit 2. Even when electricity is not supplied to the electronic component 5 via the heat diffusion circuit 2 and the transistor is stopped, the heat diffusion circuit 2 still functions to diffuse residual heat from the transistor. This embodiment may be applied to the fifth embodiment. Also, the case where the heat spreading circuit 2 dissipates heat generated by a transistor has been described as an example. However, if the heat spreading circuit 2 is designed as a circuit that passes a large current, the heat spreading circuit 2 also plays a role in dissipating heat generated by the resistance of a conductor when a large current flows. Moreover, when the heat diffusion circuit 2 is designed so that a current flows therethrough, it serves both as a circuit through which a current flows and as a circuit for dissipating heat from the electronic component 5. In this specification, such a circuit is referred to as a dual-current electric / thermal circuit. In Fig. 22, the arrow (gray) A1 indicates the flow of heat, and the arrow (black) A2 illustrates the current. Note that the arrow A2, which is the direction of the current, may be reversed.

[0071] [Seventh embodiment] <substrate> The structure of a substrate according to a seventh embodiment for carrying out the invention will be described with reference to Figures 15 and 16. Components having the same structure as those of the substrate 1C of the third embodiment are given the same reference numerals and will not be described. The substrate 1G of the present invention is characterized in that a plurality of heat diffusion circuits (2G1 and 2G2) are provided, and the heat diffusion circuits are provided with a support member 81 having higher heat dissipation performance than the insulator 3 via the insulator 3, and the support member 81 is provided across the plurality of heat diffusion circuits.

[0072] <Heat diffusion circuit> The heat diffusion circuit 2G1 includes a first pedestal 21G1 and a second pedestal 22G1. The heat diffusion circuit 2G1 is formed so that the lower side (the side in contact with the insulator 3) of the second pedestal 22G1 has the widest width in the planar (left-right) direction, and is formed so that the planar width gradually narrows in the order of the upper side (the side on which the electronic component 5 is arranged) of the second pedestal 22G1, the lower side of the first pedestal 21G1, and the upper side of the first pedestal 21G1.

[0073] The heat diffusion circuit 2G2 includes a first pedestal 21G2 and a second pedestal 22G2. The heat diffusion circuit 2G2 is formed so that the lower side (the side in contact with the insulator 3) of the second pedestal 22G2 has the widest width in the planar (left-right) direction, and is formed so that the planar width gradually narrows in the order of the upper side (the side on which electronic components are arranged) of the second pedestal 22G2, the lower side of the first pedestal 21G2, and the upper side of the first pedestal 21G2. The thermal diffusion circuits 2G1 and 2G2 are formed by an etching process, which will be described later. Other structures of the heat diffusion circuit 2G1 and the heat diffusion circuit 2G2 are similar to those of the heat diffusion circuit 2 of the first embodiment.

[0074] <Insulator> The insulator 41G1 is disposed so as to be in contact with the upper surface of the insulator 3, the side surface of the second pedestal 22G1 and the side surface of the second pedestal 22G2, and the upper surface of the insulator 41G1 is at the same height as the upper surfaces of the first pedestal 21G1 and the first pedestal 21G2. In addition, the insulator 41G2 is positioned so as to be in contact with the side of the insulator 41G1, the side of the first pedestal 21G1, and the upper surface of the second pedestal 22G1, and is also positioned so as to be in contact with the side of the insulator 41G1, the side of the first pedestal 21G2, and the upper surface of the second pedestal 22G2. The insulators 41G1 and 41G2 have a connection surface 43G in the plate thickness direction (vertical direction) and do not have a connection surface in the planar direction. The insulators 41G1 and 41G2 are supporting insulators, and the material thereof is the same as that of the supporting insulator (insulators 41 and / or 42) of the thermal diffusion circuit 2 of the first embodiment.

[0075] <Support member> The support member 81 plays a role in supporting the heat diffusion circuits 2G1 and 2G2 and increasing the rigidity of the board. It also plays a role in dissipating heat from the electronic components 5 that is transmitted through the heat diffusion circuits 2G1 or 2G2 and the insulator 3 in that order. The support member 81 is disposed below the insulator 3 and is disposed across the second pedestal 22G1 and the second pedestal 22G2 via the insulator 3. This structure has the effect of supporting the heat diffusion circuits 2G1 and 2G2, obtaining rigidity, and dissipating heat evenly. Moreover, the support member 81 may be made of a material having a higher heat dissipation performance than the insulator 3, and specific examples thereof include copper and aluminum. The support member 81 may be an electrolytic conductor made by copper plating or may be rolled copper. However, in the case of an electrolytic conductor made by copper plating, it can be provided thinly in the plate thickness direction, and has the effect of enabling the weight of the substrate 1G to be reduced while maintaining heat dissipation. In addition, in the case of a rolled conductor (rolled copper), the rigidity of the substrate 1G can be increased.

[0076] [Substrate manufacturing method] Next, a method for manufacturing the substrate 1G will be described with reference to FIGS. 17(A), a composite substrate 20G is prepared in which a rolled conductor (copper) 20G1 is bonded to the upper side of an insulator 3 and a rolled conductor (copper) 20G2 is bonded to the lower side of the insulator 3. This process is referred to as a composite substrate preparation process.

[0077] Next, as shown in Fig. 17(B), an etching resist 25G is provided on the surface of the rolled conductor 20G1. A process is performed in which the portions of the upper surface of the rolled conductor 20G1 that correspond to the first pedestal 21G1 and the second pedestal 22G1, and the first pedestal 21G2 and the second pedestal 22G2 are covered with the etching resist 25G. This process is referred to as a first intermediate resist preparation process. In the first intermediate resist preparation step, the entire lower surface of the rolled conductor 20G2 may also be protected by the etching resist 25G.

[0078] Next, the rolled conductor 20G1 is etched while covered with the etching resist 25G from the first intermediate resist preparation step. This step is called the intermediate etching step. The etching is performed until the insulator 3 is exposed, as shown in FIG. 17(C). This step forms a recess 45G on one side of the rolled conductor 20G1, forming an intermediate 21G. Then, the etching resist 25G provided in the first intermediate resist step is removed.

[0079] 18A, a step of filling recess 45G with insulating resin is performed. This step is referred to as a first intermediate insulating resin filling step. Through this process, the insulator 41G1 is formed. After the first intermediate insulating resin filling step, the upper surfaces of the insulator 41G1 (insulating resin) and the intermediate body 21G may be subjected to a surface smoothing process so that the surfaces of the insulator 41G1 (insulating resin) and the intermediate body 21G are flat. This step is referred to as a fourth surface smoothing step.

[0080] 18(B), a process is performed in which the portions of the upper surface of the preform 21G that will become the first seat 21G1 and the first seat 21G2 are covered with an etching resist 26G. This process is referred to as a second preform resist forming process. In addition, in the second intermediate resist preparation step, the entire lower surface of the rolled conductor 20G2 is also protected by the etching resist 26G.

[0081] Next, while covered with the etching resist 26G in the second intermediate resist forming process, the intermediate 21G is etched (half etched). This process is called the second intermediate etching process. By this process, a recess 46G is formed in the intermediate 21G as shown in FIG. 18(C). Then, the etching resist 26G provided in the second intermediate resist process is removed, resulting in the state shown in FIG. 19(A). Furthermore, by this process, the thermal diffusion circuits 2G1 and 2G2 are completed.

[0082] Next, as shown in FIG. 19B, a step of filling the recess 46G with insulating resin is performed. This step is called a recess insulating resin filling step. This step forms the insulator 41G2, which is the supporting insulator. This step also forms the connection surface 43G. In addition, the rolled conductor 20G2 functions as a support member 81. After the recess edge resin filling step, the upper surfaces of the insulator 41G2 (insulating resin), the thermal diffusion circuits 2G1 and 2G2, and the insulator 41G1 may be smoothed so that the surfaces of the insulator 41G2 (insulating resin) and the thermal diffusion circuits 2G1 and 2G2 and the insulator 41G1 are flat. This step is called a fourth surface smoothing step.

[0083] Thereafter, similarly to the first embodiment, solder resist is provided on the upper and lower surfaces of the substrate 1G to protect the substrate surface, and a heat dissipation member such as a heat sink is provided below the support member 81 to further improve the heat dissipation efficiency of the substrate. Also, electronic members 5 and wirings 61 and 62 are arranged to form an electronic device.

[0084] In this embodiment, an example has been given of the case where the entire rolled conductor 20G2 is covered with etching resist in the first intermediate resist creation process and the second intermediate resist creation process, but a portion of the rolled conductor 20G2 may be etched so that the rolled conductor 20G2 remains as a support member 81 to support the thermal diffusion circuits 2G1 and 2G2. In this embodiment, the insulator 3 may be an insulating sheet made of insulating resin that does not contain glass fibers, or a plate-shaped insulator made of insulating resin and a sheet-shaped reinforcing material with woven glass fibers (conventionally called prepreg). In the case of an insulating sheet made of insulating resin, the absence of glass fibers has the effect of reducing the weight of the board, and further, if a thermally conductive filler is filled, the effect of improving heat dissipation can be achieved. In addition, in the case of a plate-shaped insulator made of insulating resin and a sheet-shaped reinforcing material with woven glass fibers, the effect of increasing the rigidity of the board is achieved.

[0085] Further, in this embodiment, the case where the substrate 1G has two heat diffusion circuits has been exemplified, but the substrate 1G may have one (single) heat diffusion circuit or three or more heat diffusion circuits. [Industrial Applicability]

[0086] The electronic device of the present invention is an electronic device equipped with the substrate of the present invention, and its applications are not particularly limited, but examples thereof include automobiles, aircraft, unmanned aerial vehicles, mobile phones, smartphones, personal computers, LED modules, power semiconductor modules, etc. With this electronic device and substrate, the heat dissipation performance of electronic components can be improved. [Explanation of symbols]

[0087] 1A board, 1B board, 1C board, 1D board, 1E board, 2 heat diffusion circuit, 3 insulator, 5 electronic component, 7 electric circuit, 20 rolled conductor, 21 first base, 22 second base, 25 etching resist, 26 etching resist, 27 etching resist, 28 base member, 41 insulator, 42 insulator, 43 connection surface, 45 recess, 46 recess, 61 wiring, 62 wiring, 70 conductor, 71 other circuit, 72 underside conductor, 211 first base upper part, 212 first base lower part, 221 second base upper part, 222 second base lower part, 281 base member upper part, 282 base member lower part, 283 base member center part

Claims

1. The device is equipped with a heat diffusion circuit that utilizes temperature differences to allow heat to flow, and an insulator. the heat spreading circuit is made of a conductor and has a first base and a second base; the first base and the second base have an integral structure with no connecting surface, and the second base has a thickness greater than that of the first base, the first seat is disposed on a side on which an electronic component is disposed, the second seat is disposed on a side opposite to a side on which the electronic component is disposed, The second seat has a structure extending in a planar direction further than the first seat, the insulator includes an insulator disposed on a side of the second base opposite to a side on which the electronic component is disposed, and a supporting insulator that supports the heat diffusion circuit in a plate shape; The support insulator includes an insulator extending in a planar direction and disposed at a side surface of the first base, and an insulator extending in a planar direction and disposed at a side surface of the second base, a connection surface is provided between an insulator extending in a planar direction and disposed at a side surface of the first base and an insulator extending in a planar direction and disposed at a side surface of the second base, the connection surface being located at the same thickness as a boundary between the first base and the second base in a plate thickness direction; a surface of the first seat on which an electronic component is disposed and a surface of an insulator disposed at a side surface of the first seat and extending in a planar direction are flat surfaces; a surface of the second seat opposite to a side on which an electronic component is disposed and a surface of an insulator disposed at a side surface of the second seat and extending in a planar direction are flat surfaces; The substrate, wherein the heat diffusion circuit is a circuit for connecting an electronic component to a power source.

2. The substrate described in claim 1, characterized in that the heat diffusion circuit is made of a rolled conductor.

3. When the thermal diffusion circuit is cut in the plate thickness direction, on one side of the heat diffusion circuit in a planar direction, a center side of the first pedestal in a plate thickness direction does not extend further in the planar direction than a center side of the second pedestal in a plate thickness direction, and a center side of the second pedestal in a plate thickness direction does not extend further in the planar direction than a center side of the first pedestal in a plate thickness direction, 2. The substrate according to claim 1, characterized in that on the other side of the heat spreading circuit in the planar direction, a surface of the second base at a central side in the plate thickness direction extends to the other side beyond the central side in the plate thickness direction of the first base, and the surface of the second base at a central side in the plate thickness direction is in contact with an insulator extending in the planar direction and arranged at a side position of the first base.

4. The substrate described in claim 1, characterized in that the heat diffusion circuit is a circuit for connecting to an electrode of a transistor of the electronic component.

5. A substrate as described in claim 1, characterized in that an electrical circuit is arranged on the side of the heat diffusion circuit on which the electronic components are arranged.

6. An electronic device comprising the substrate according to any one of claims 1 to 5 and an electronic component.

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