JP4395739B2 - Radiator, manufacturing method thereof, power module substrate and power module - Google Patents

Description

  The present invention relates to a heat radiating body configured to dissipate heat of a heat generating body to the outside and a manufacturing method thereof, and more particularly to a heat radiating body suitable for a power module used in a semiconductor device that controls a large current and a large voltage, and The present invention relates to a manufacturing method, a power module substrate, and a power module.

  The following configuration is generally known as a power module in which this type of heat radiator is used. That is, a semiconductor chip as a heating element is provided on one surface side of the insulating substrate, a heat radiator is provided on the other surface side of the insulating substrate, and the heat of the semiconductor chip is dissipated outside through the heat radiator. . Among the components of this power module, the thermal expansion coefficient of the insulating substrate and the semiconductor chip is small compared to the thermal expansion coefficient of the heat radiating element. Therefore, when this power module is used under a temperature cycle by the heat generating element, it is insulated. Due to the difference between the thermal expansion coefficient of the substrate and the thermal expansion coefficient of the heat dissipating member, peeling may occur at these joint interfaces.

As a means for solving this problem, the heat sink is a low heat composed of a Ni—Co—Fe alloy or the like between the heat dissipator bodies as a high thermal conductor composed of Cu, Cu alloy, Al, Al alloy or the like. A laminated structure in which an expansion body is disposed is known (for example, see Patent Document 1). As a manufacturing method of the heat radiating body, through holes are formed in the surface of the low thermal expansion body, the heat radiating body is placed on the front and back surfaces of the low thermal expansion body, and these are pressurized and heated in this state. A method is known in which the heat dissipating body is plastically deformed and allowed to flow into the through hole of the low thermal expansion body, thereby manufacturing the heat dissipating body having the laminated structure.
Japanese Patent Laid-Open No. 9-1361

  By the way, in the prior art, in order to manufacture the radiator by flowing the radiator body into the through hole from the front and back surfaces of the low thermal expansion body by the pressure heating, in the manufactured radiator, the front and rear surfaces of the low thermal expansion body. There is a problem that it is difficult to make the thickness of the heat dissipating body main body substantially uniform. That is, it is difficult to make the thickness of the heat dissipating body main body respectively disposed on the front and back surfaces of the low thermal expansion body uniform in the direction along each surface, and each heat dissipating body main body is the through hole. There was a problem that it was difficult to make the volume flowing into the inside uniform.

  Therefore, when this heat radiator is used as a power module and placed under a temperature cycle, the deformation stress generated by thermal expansion is different in each heat radiator body, and the heat radiator is likely to warp. There was a problem. In this case, peeling occurs at the bonding interface between the radiator and the insulating substrate having the heating element, and the cooling sink is disposed on the lower surface of the radiator (the surface opposite to the insulating substrate). There is a case where a gap is generated between the radiator and the cooling sink, and there is a problem that it is difficult to provide the power module with good heat dissipation characteristics.

  The present invention has been made in consideration of such circumstances, and is capable of suppressing the occurrence of warping even when used under a temperature cycle, and has a low thermal expansion property and high thermal conductivity, and its manufacture. It is an object to provide a method, a power module substrate, and a power module.

In order to achieve the above object, the present invention proposes the following means.
The invention according to claim 1 is a three-layer structure in which a low thermal expansion body having a thermal expansion coefficient lower than that of the heat dissipation body is disposed between the upper and lower heat dissipation body, and the surface of the heat dissipation body. A heat dissipating body configured to conduct and dissipate heat of the heat generating element provided on the side in the stacking direction of the heat dissipating body and the low thermal expansion body, and in a through hole formed in the low thermal expansion body A hole filling material having a higher thermal conductivity than the heat dissipating body is disposed, and the heat dissipating body, and the low thermal expansion material and the hole filling material facing the heat dissipating body are brazed and joined over the entire surface. The heat radiator body is preferably a Cr-Zr-Cu alloy or Ni-Si-Cu alloy, the low thermal expansion body is preferably an Fe-Ni alloy, and the hole filling material is Is preferably pure Cu.

According to the heat dissipating body according to the present invention, since the heat dissipating body main body, the low thermal expansion material and the hole filling material are brazed and joined, the heat dissipating body has a low thermal expansion body. Therefore, the fall of the thermal conductivity of this heat radiator can be suppressed. Therefore, a radiator having both low thermal expansion and high thermal conductivity can be obtained.
In particular, if the heat dissipating body, the low thermal expansion body, and the hole filling material are formed of the above-described materials, it is possible to reliably provide low thermal expansion and high thermal conductivity and to increase the strength of the heat dissipating body. Therefore, in a configuration in which the heat generating body side having a smaller thermal expansion coefficient than the heat radiating body and the heat radiating body are joined, even when this is used under a temperature cycle, it is possible to prevent the heat radiating body from warping.

  The invention according to claim 2 is the heat dissipating body according to claim 1, wherein the through-hole has an occupied area ratio in a region corresponding to the heating element on a surface of the low thermal expansion body, and a peripheral region of the corresponding region. It is characterized by being formed so as to be smaller than the occupied area ratio.

  According to the heat dissipating body according to the present invention, a decrease in bending rigidity in the corresponding region of the heat dissipating body can be suppressed to the minimum, and the occurrence of warpage in the corresponding region due to the heat from the heating element can be suppressed.

  The invention according to claim 3 is the heat radiator according to claim 1 or 2, wherein the opening end of the through hole is gradually reduced in diameter from the opening end toward the penetration direction, and radially inward. It is characterized by being a convex curved surface portion that is convex toward the surface.

  According to the heat dissipating body according to the present invention, the convex curved surface portion acts as a stress relieving portion, and in a state where the heat dissipating member is placed under a temperature cycle, the hole filling material is joined to the heat dissipating member main body. It is possible to suppress the occurrence of stress concentration. Therefore, since it can suppress that a crack generate | occur | produces in the said junction part, the high thermal conductivity of a thermal radiation body can be maintained over a long term.

The invention according to claim 4 is a three-layer structure in which a low thermal expansion body having a thermal expansion coefficient lower than that of the heat dissipation body is disposed between the upper and lower heat dissipation body, and the surface of the heat dissipation body. A method of manufacturing a heat radiating body configured to conduct and dissipate heat of a heat generating body provided on the side in the stacking direction of the heat radiating body main body and the low thermal expansion body, and a through hole formed in the low thermal expansion body A hole filling step of disposing a hole filling material having a higher thermal conductivity than the heat dissipating body, and after the hole filling step, the heat dissipating body, the low thermal expansion body facing the heat dissipating body, and the A bonding step of bonding the hole filling material over the entire surface by brazing.

  According to the method of manufacturing a radiator according to the present invention, since the hole filling step and the bonding step are separately provided, the thickness of the radiator body respectively disposed on the front and back surfaces of the low thermal expansion body is made substantially uniform. It is possible to suppress the occurrence of warping of the heat dissipator when the heat dissipator is used.

According to a fifth aspect of the present invention, in the method for manufacturing a radiator according to the fourth aspect , in the hole filling step, a filling material having a volume larger than a space volume of the through hole formed in advance is press-fitted into the through hole. It is characterized by that.

  According to the method for manufacturing a heat radiator according to the present invention, the hole filling material can be spread all over the inside of the through hole by press-fitting.

The invention according to claim 6 includes a heat radiating body in which a low thermal expansion body having a thermal expansion coefficient lower than the thermal expansion coefficient of the heat radiating body is laminated on the heat radiating body, and an insulating substrate including a heating element, 4. The power module substrate, wherein the insulating substrate is disposed on one surface of the heat dissipating body and configured to conduct and dissipate heat of the heat generating member in the stacking direction, wherein the heat dissipating member is of claim 1 to 3 . It is a heat radiator according to any one of the above.

According to a seventh aspect of the present invention, there is provided a heat radiating body in which a low thermal expansion coefficient having a thermal expansion coefficient lower than the thermal expansion coefficient of the heat radiating body is laminated on the heat radiating body, an insulating substrate including the heating element, and a refrigerant inside A cooling sink portion configured to circulate, and the insulating substrate is disposed on one surface of the heat dissipating body, and the cooling sink portion is disposed on the other surface of the heat dissipating body. A power module configured to conduct and dissipate from one surface of the radiator to the other surface, wherein the radiator is the radiator according to any one of claims 1 to 3. To do.

According to the heat dissipating body according to the present invention, although the heat dissipating body has a configuration having a low thermal expansion body, it is possible to suppress a decrease in the thermal conductivity of the heat dissipating body, and to achieve low thermal expansion and high thermal conductivity. A heat radiator having both of the above is obtained.
In addition, according to the method for manufacturing a radiator according to the present invention, since the hole filling step and the joining step are separately provided, the thickness of the radiator body respectively disposed on the front and back surfaces of the low thermal expansion body is made substantially uniform. It is possible to suppress the occurrence of warpage of the heat radiating body when the heat radiating body is used.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall view showing a power module to which a radiator according to an embodiment of the present invention is applied.
This power module roughly includes a power module substrate 10 and a cooling sink portion 31 as shown in FIG.
The power module substrate 10 includes an insulating substrate 11 made of, for example, AlN, Al ₂ O ₃ , Si ₃ N ₄ , SiC, a circuit layer 12 disposed on the upper surface of the insulating substrate 11, and an insulating substrate 11. And a semiconductor chip (heating element) 30 disposed on the upper surface of the circuit layer 12, and a radiator 16 disposed on the lower surface of the metal layer 13.

The circuit layer 12 and the metal layer 13 are formed of pure Al, Al alloy, pure Cu, Cu alloy or the like, and are laminated and bonded to the upper and lower surfaces of the insulating substrate 11 by soldering or brazing. Is joined to the upper surface of the circuit layer 12.
And the heat sink 16 is joined to the lower surface of the metal layer 13 by solder 15 or by brazing, diffusion bonding or the like, and the cooling sink portion 31 is further attached to the heat sink 16 by means of mounting screws 33 so that the power module is mounted. It is configured.

  In addition, a circulation hole 31a connected to a refrigerant circulation means (not shown) that supplies and collects a refrigerant 32 such as a coolant and cooling air is formed inside the cooling sink portion 31, and is supplied into the circulation hole 31a. The heat transferred from the semiconductor chip 30 to the heat radiating body 16 is recovered by the generated refrigerant 32, and the refrigerant circulating means recovers the refrigerant 32 from which the heat has been recovered, and a new refrigerant 32 is supplied, and the above is repeated. As a result, heat from the semiconductor chip 30 is dissipated from the power module.

  The radiator 16 includes a radiator body 17 having a thermal conductivity of 150 W / m · K or more and a tensile strength of 500 MPa or more, and a low thermal expansion made of a material having a thermal expansion coefficient lower than that of the radiator body 17. The low thermal expansion body 18 is provided between the heat radiating body main bodies 17 and these are joined by brazing.

  As shown in FIG. 2, a plurality of through holes 19 having a hexagonal shape in plan view are formed in the low thermal expansion body 18, and in these through holes 19, the thermal conductivity is higher than that of the radiator body 17 ( 200 W / m · K or more) The hole filling material 21 is provided. The hole-filling material 21 and the radiator body 17 are joined to each other by brazing, and the heat-radiator body 17 and the hole-filling material 21 having relatively high thermal conductivity are continuous in the stacking direction. It has become the composition. Thereby, if the heat radiator 16 has the low thermal expansion body 18, the thermal conductivity of the heat radiator 16 is lowered as much, but the reduction of the thermal conductivity can be suppressed as much as possible.

  In addition, as shown in FIG. 2, the through hole 19 has an occupied area ratio in the region X corresponding to the insulating substrate 11 in the surface of the low thermal expansion body 18 as compared to an occupied area ratio in the peripheral region Y of the corresponding region X. It has been made smaller. Specifically, it is determined by the material and size of the insulating substrate 11 and the heat dissipating body 17 and the like, but in the present embodiment, the corresponding region X has about 30% or more of the surface area of the low thermal expansion body 18. The through hole 19 is formed by occupying 50% or less, and the through hole 19 is formed in the peripheral region Y by occupying about 40% to 70% of the surface area of the low thermal expansion body 18.

As described above, by changing the occupation area ratio of the through-holes 19 between the corresponding region X and the peripheral region Y in the surface of the low thermal expansion body 18, it is possible to suppress a decrease in bending rigidity in the corresponding region X, and to dissipate heat. It is possible to suppress a decrease in the thermal conductivity of the entire 16.
In addition, by making the through-holes 19 have a hexagonal shape in plan view, it is possible to easily realize a substantially constant interval between the through-holes 19 on the surface of the low thermal expansion body 18. For each of X and Y, the thermal conductivity can be made uniform in the direction along the surface of the low thermal expansion body 18.
Further, as shown in FIG. 3, the opening end portion of the through hole 19 is gradually reduced in diameter from the opening end toward the penetrating direction, and has a convex curved surface portion 19a that is convex radially inward. In addition, the hole filling material 19 is arranged over substantially the entire area inside the through hole 19 including the surface of the concave curved surface portion 19a.

In the present embodiment, the radiator body 17 is made of a Cr—Zr—Cu alloy or a Ni—Si—Cu alloy. By forming the heat dissipating body 17 from these alloy materials, it becomes possible to increase the strength as compared with the case where pure metal such as pure Al is adopted, and creep due to the temperature cycle when the heat dissipating body 16 is used. Deformation can be suppressed.
The low thermal expansion body 18 is made of an Fe—Ni alloy, and the hole filling material 21 is made of pure Cu. As the Fe—Ni-based alloy of the low thermal expansion body 18, an Invar alloy (thermal expansion coefficient is about 2.0 × 10 ⁻⁶ / ° C. or less) is particularly preferable. This Invar alloy is an alloy that hardly undergoes thermal expansion near room temperature, and has a composition ratio of 64.6 mol% Fe and 35.4 mol% Ni. However, Fe containing other inevitable impurities is also called an Invar alloy.
Furthermore, as the brazing material for joining the heat dissipating body 17, the low thermal expansion body 18 and the hole filling material 21, in this embodiment, an Ag—Cu based brazing material defined in JIS Z 3261 is used.

  As described above, since the radiator 16 has the low thermal expansion body 18, the thermal expansion coefficient of the entire radiator 16 is lower than the thermal expansion coefficient of the radiator body 17, and the thermal expansion coefficient of the radiator 16 and the insulating substrate 11. The difference from the thermal expansion coefficient will be as close as possible.

The thickness A of the low thermal expansion body 18 is 0.3 to 1.3 times the thickness B of the heat dissipating body 17. This is because if the low thermal expansion body 18 is provided in the heat radiating body 16 itself, the thermal conductivity is lowered accordingly, so that the reduction of the thermal conductivity is suppressed as much as possible, and in order to suppress the reduction of the thermal conductivity, If the thickness A of the low thermal expansion body 18 is unnecessarily thin, the influence of the low thermal expansion body 18 that contributes to the thermal expansion coefficient of the heat radiating body 16 itself is reduced. This is to avoid being substantially the same as the coefficient.
That is, by making the thickness A of the low thermal expansion body 18 0.3 times or more and 1.3 times or less the thickness B of the radiator body, the thermal expansion coefficient of the radiator 16 is reduced, that is, the curvature of the radiator 16 is reduced. Both suppression of generation and suppression of decrease in thermal conductivity of the radiator 16 can be achieved.

Next, the manufacturing method of the heat radiator 16 configured as described above will be described.
First, in the low thermal expansion body 18, the corresponding area X and the peripheral area Y have different occupation area ratios, and a plurality of through holes 19 are formed, and the filling of a volume larger than the space volume of each through hole 19 is made. The material 19 is formed of pure Cu. As the hole filling material 21, for example, there is a so-called rivet shape as shown in FIG.

  In a state where the hole filling material 21 is fitted into the through hole 19, the hole filling material 21 is pressed into the through hole 19 by pressurizing in the thickness direction of the low thermal expansion body 18. A hole filling material 21 is disposed inside. At this time, since the hole filling material 21 is formed in a volume larger than the space volume of the through hole 19, the excessive volume of the hole filling material 21 flows outward in the radial direction of the through hole 19, In close contact with the inner peripheral surface of 19 and also flows on the surface of the convex curved surface portion 19a of the through hole 19, thereby filling the entire area inside the through hole 19 including the surface of the concave curved surface portion 19a. 21 will go around.

  Thereafter, a brazing material or foil (not shown) is placed on substantially the entire front and back surfaces of the low thermal expansion body 18, and further, the radiator body 17 is placed on the surface of the brazing material or foil, and then these are heated in a heated state. By applying pressure in the stacking direction, the radiator body 17, the low thermal expansion body 18, and the hole filling material 21 are joined by brazing to form the radiator 16.

Specific examples of the above manufacturing method will be described.
A brazing material made of 72Ag-28Cu with a thickness of about 50 μm, a heat radiator body 17 made of a Cu—Cr—Zr-based alloy with a thickness of about 1.0 mm, a width of about 80 mm, and a length of about 200 mm, and an Fe-36Ni-based alloy And a low thermal expansion body 18 having a thickness of about 1.0 mm, a width of about 80 mm, and a length of about 200 mm. A plurality of through holes 19 having an outermost diameter of about 5.8 mm are formed on the surface of the low thermal expansion body 18 so as to have a pitch interval of about 5.8 mm, and the holes are formed in the through holes 19 as described above. A filling material 21 is disposed.

Thereafter, the low thermal expansion body 18, the brazing material, and the heat radiating body main body 17 are laminated as described above, and are pressurized in the laminating direction at a pressure of 0.1 MPa or more. atmosphere _(H 2, _0.2~0.4Torr) placed in a by bonding oven. And after raising the temperature in a joining furnace to about 760 degreeC at 20 degreeC / min, this temperature is hold | maintained for about 60 minutes, and, thereby, brazing material, the heat radiator main body 17, the low thermal expansion body 18, and a hole The temperature of the filling material 21 is made uniform. Thereafter, the temperature is further raised to about 830 ° C. at 20 ° C./minute, and this temperature is maintained for about 20 minutes, thereby melting the brazing material.

Then, the vacuum reducing atmosphere is discharged from the inside of the joining furnace, the vacuum atmosphere is sucked, the furnace temperature is cooled to about 200 ° C., the vacuum atmosphere is further discharged, and N ₂ gas is sucked. Quench rapidly to room temperature.
As described above, the heat radiating body 17, the low thermal expansion body 18 and the hole filling material 21 are joined, and the heat radiating body 16 is obtained.

  As described above, according to the radiator 16 according to the present embodiment, the radiator body 17, the low thermal expansion material 18 and the hole filling material 21 are brazed and joined. Despite the configuration having the body 18, it is possible to suppress a decrease in the thermal conductivity of the heat radiating body 16. Therefore, the heat radiating body 16 having both low thermal expansion and high thermal conductivity is obtained.

  In particular, the heat dissipating body 17 is formed of a Cr—Zr—Cu alloy or a Ni—Si—Cu alloy, the low thermal expansion member 18 is formed of a Fe—Ni alloy, and the hole filling material 21 is formed of pure Cu. Therefore, the heat dissipating body 16 can be surely provided with low thermal expansion and high thermal conductivity, and high strength can be achieved. Therefore, the insulating substrate 11 side having a smaller thermal expansion coefficient than the heat dissipating body 16 can be provided. In the configuration in which the heat radiating body 16 is joined, even if it is used under a temperature cycle, the heat radiating body 16 can be prevented from warping.

  Further, since the through-hole 19 has a larger occupied area ratio in the peripheral region Y than a occupied area ratio in the corresponding region X in the surface of the low thermal expansion body 18, the corresponding region X in the heat radiator 16. It is possible to suppress a decrease in bending rigidity at the minimum, and to prevent the corresponding region X from being warped by heat from the semiconductor chip 30.

  Furthermore, since the opening portion of the through hole 19 is a convex curved surface portion 19a, the stress generated at the joint portion of the hole filling material 21 with the radiator body 17 when the radiator 16 is placed under a temperature cycle. Concentration will be eased. Therefore, since it can suppress that a crack generate | occur | produces in the said junction part, the high thermal conductivity of the heat radiator 16 can be maintained over a long period of time.

  Moreover, according to the manufacturing method of the heat radiating body 16 according to the present embodiment, since the hole filling step and the joining step described above are separately provided, the thickness of the heat radiating body main body 17 respectively disposed on the front and back surfaces of the low thermal expansion body 18. It is possible to make the thickness A substantially uniform, and it is possible to suppress the occurrence of warpage of the heat radiating body 16 when the heat radiating body 16 is used. Further, in the hole filling step, since the hole filling material 21 having a volume larger than the space volume of the through hole 19 formed in advance is press-fitted into the through hole 19, the hole filling material 21 is almost entirely inside the through hole 19 by press fitting. Can be spread over.

  In the above-described embodiment, an example in which an Fe—Ni-based alloy is used as the low thermal expansion body 18 laminated on the heat radiating body 17 is shown. However, other low thermal expansion bodies such as high carbon steel (Fe—C) are used. ), 42 alloy, molybdenum (Mo), tungsten (W), etc., the same effects can be obtained.

  Furthermore, although the structure which has arrange | positioned the cooling sink part 31 in the heat radiator 16 was shown, it is good also as a structure which provided not only this structure but a corrugated fin. That is, a joining portion joined to the surface of the heat radiating body 16 via a brazing material, a rising portion provided at one end of the joining portion and rising up perpendicular to the joining portion, and provided at an upper end of the rising portion and parallel to the joining portion and A projecting portion including a flat portion extending in a separating direction and a folded portion provided at one end of the flat portion and orthogonal to the flat portion and folded back toward the radiator 16 is continuously repeated along the creeping direction of the radiator 16. It is good also as a structure provided. In this configuration, the rising portion, the flat portion, the folded portion, and the surface of the radiator 16 form a space.

  Moreover, in the said embodiment, although the heat radiator 16 was applied to the power module of the semiconductor device, you may use it attaching to other heat generating bodies and heat sources, without limiting to this. Further, the rivet-shaped hole filling material 21 is disposed in the through-hole 19 by press-fitting, but the powder material is filled in the through-hole 19 and then the powder material is pressurized and heated to be sintered. Also good. Further, the shape of the through hole 19 of the low thermal expansion body 18 is not limited to the hexagonal shape shown in FIG.

  A heat radiator having both low thermal expansibility and high thermal conductivity is provided, and even when the heat radiator is used under a temperature cycle, warpage of the heat radiator is suppressed.

1 is an overall view showing a power module to which a heat radiator according to an embodiment of the present invention is applied. It is a top view of the low thermal expansion body shown in FIG. It is an expanded sectional side view of the heat radiator shown in FIG. It is an expanded sectional side view which shows the process of pressing-in a hole-filling material in the manufacturing process which manufactures the heat radiator shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Power module board | substrate 11 Insulation board | substrate 16 Heat radiating body 17 Heat radiating body main body 18 Low thermal expansion body 19 Through-hole 19a Convex-curved surface part 21 Filling material 30 Semiconductor chip (heating element)
X corresponding area Y peripheral area

Claims (7)

A three-layer structure in which a low thermal expansion coefficient having a thermal expansion coefficient lower than the thermal expansion coefficient of the radiator body is arranged between the upper and lower radiator bodies, and the heating element provided on the surface side of the radiator body A heat radiator configured to conduct and dissipate heat in the stacking direction of the heat radiator body and the low thermal expansion body ,
In the through-hole drilled in the low thermal expansion body, a hole filling material having a higher thermal conductivity than the radiator body is disposed,
A heat radiator, wherein the heat radiator body, the low thermal expansion material and the hole filling material facing the heat radiator body are brazed and joined over the entire surface . The heat radiator according to claim 1,
The through hole is formed such that, in the surface of the low thermal expansion body, an occupied area ratio in a region corresponding to the heating element is smaller than an occupied area ratio in a peripheral region of the corresponding region. Heatsink. In the heat radiator according to claim 1 or 2,
The opening end portion of the through hole is a convex curved surface portion that is gradually reduced in diameter as it goes from the opening end toward the penetrating direction and that protrudes radially inward. . A three-layer structure in which a low thermal expansion coefficient having a thermal expansion coefficient lower than the thermal expansion coefficient of the radiator body is arranged between the upper and lower radiator bodies, and the heating element provided on the surface side of the radiator body A method of manufacturing a radiator that is configured to conduct and dissipate heat in the stacking direction of the radiator body and the low thermal expansion body ,
A hole filling step of disposing a hole filling material having a higher thermal conductivity than the heat dissipating body in the through hole formed in the low thermal expansion body;
After the hole-filling step, the heat-radiating member main body, and a joining step of joining the low thermal expansion body and the hole-filling material facing the heat-dissipating body main body by brazing over the entire surface . Production method. In the manufacturing method of the heat radiator of Claim 4,
The said hole-filling process press-fits the hole-filling material of the volume larger than the space volume of the said through-hole previously formed in the said through-hole, The manufacturing method of the heat radiator characterized by the above-mentioned. The radiator body includes a radiator in which a low thermal expansion coefficient having a thermal expansion coefficient lower than the thermal expansion coefficient of the radiator body is laminated, and an insulating substrate including the heating element.
The insulating substrate is disposed on one surface of the heat dissipating body, and the power module substrate is configured to conduct and dissipate heat of the heating element in the stacking direction,
A power module substrate, wherein the heat dissipating member is a heat radiator according to any one of claims 1 to 3. Cooling structure in which a heat radiating body is laminated with a low thermal expansion body having a thermal expansion coefficient lower than that of the heat radiating body, an insulating substrate provided with the heat generating body, and a cooling medium configured to circulate inside. With a sink part,
The insulating substrate is disposed on one surface of the radiator, and the cooling sink portion is disposed on the other surface.
A power module configured to conduct and dissipate heat of the heat generating body from one surface of the heat radiating body to the other surface,
A power module, wherein the radiator is the radiator according to any one of claims 1 to 3 .

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