JP2013038183A - Cooling device and method for manufacturing the same - Google Patents

Abstract

The present invention provides a cooling device and a method for manufacturing the same, in which both high mechanical strength of a mounting portion provided for attaching the cooling device to a module or the like and good thermal conductivity of the cooling device itself are achieved.
A cooling device includes: a cooling member having a heat medium flow path provided on a member formed of aluminum or an aluminum alloy; and a plate-shaped member arrangement surface of the cooling member. The plate-like member 12 arranged so that a part of the cooling member 11 is exposed, the exposed part 11c where a part of the cooling member 12 is exposed from the plate-like member 12, and the surface of the plate-like member 12 around it And a heat conductive layer 13 formed by accelerating a powder made of copper or a copper alloy together with a gas and spraying the powder in a solid state to deposit the powder.
[Selection] Figure 2

Description

  The present invention relates to a cooling device and a manufacturing method thereof.

  Various modules and devices such as computer CPUs, chipsets, AV equipment and automotive power transistors (hereinafter collectively referred to as modules, etc.) are usually provided with cooling devices to prevent overheating of the modules. It is done. As an example of the cooling device, a cooling member (heat sink) in which a heat medium moving path is provided in an aluminum alloy member is used. The heat sink is usually provided with a heat conductive layer formed of copper or the like, and the heat generated from the chip or the like is transferred to the cooling unit main body through the heat conductive layer and radiated to the outside, thereby a module or the like. Can be cooled.

  In such a cooling device, it is necessary to increase the thermal conductivity from the heat sink to the heat conductive layer. For this reason, for example, in patent document 1, in order to prevent formation of the intermetallic compound which becomes a factor of thermal resistance, it is supposed to braze the copper plate which gave nickel plating with respect to the heat sink made from aluminum. Moreover, in patent document 2, after forming a thermal spray metal layer directly on the flat plate part of a heat sink by thermal spraying methods, such as cold spray, the heat processing for reducing the defect in a thermal spray metal layer is performed.

JP 2002-307165 A JP 2009-32996 A

  By the way, when attaching such a cooling device to a module or the like, for example, as shown in FIG. 8 of Patent Document 2, the end portion of the flat plate portion at the top of the heat sink extends outward from the main body, In some cases, the heat exchanger is a cross-link to a radiator that is a container for a heat exchange medium. Alternatively, the end portion of the flat plate portion may be mechanically fastened to the radiator. For this reason, high mechanical strength is required for the flat plate portion.

  Therefore, in order to improve the strength of the flat plate portion, it is conceivable to heat-treat the entire cooling device after providing a copper heat conduction layer by a cold spray method on a cooling member made of aluminum or an aluminum alloy. However, in this case, an intermetallic compound is generated at the interface between aluminum or an aluminum alloy and copper, and the thermal conductivity and mechanical reliability at this interface may be reduced.

  Alternatively, the cooling member itself may be made of a high-strength aluminum alloy that has been previously hardened. However, in general, the thermal conductivity of a high-strength aluminum alloy is considerably lower (for example, about half) than pure aluminum or an aluminum alloy that has not been work-hardened, so that the cooling efficiency of the cooling member itself decreases.

  The present invention has been made in view of the above, and in a cooling device in which a heat conduction layer is provided on a cooling member, a high mechanical strength of an attachment portion provided for attaching the cooling device to a module or the like, It is an object of the present invention to provide a cooling device and a method for manufacturing the same, which are compatible with good thermal conductivity of the cooling device itself.

  In order to solve the above-described problems and achieve the object, a cooling device according to the present invention includes a cooling member formed of a metal or an alloy and a metal or an alloy. A plate-like member arranged so that a part of the cooling member is exposed; an exposed portion where a part of the cooling member is exposed from the plate-like member; and at least the plate-like member around the exposed portion. It is characterized by comprising a heat conductive layer formed by accelerating a powder made of a metal or an alloy together with a gas toward the surface and spraying the powder in a solid state to deposit the powder.

  In the cooling device, an opening for exposing a part of the cooling member is formed in the plate-like member.

  In the cooling device, at least a part of the plate-like member extends outward from the outer periphery of the cooling member.

  In the cooling device, an end surface of the plate-shaped member that is in contact with the boundary of the exposed portion has a taper shape that extends from the cooling member side toward the surface of the plate-shaped member.

  In the cooling device, a notch into which the plate-like member is fitted is provided on the plate-like member arrangement surface of the cooling member so as to be equal to the thickness of the plate-like member.

  In the cooling device, a heat medium flow path is provided in the cooling member.

  In the cooling device, the cooling member is made of aluminum or an aluminum alloy, the plate-like member is made of an aluminum alloy, and the heat conductive layer is made of copper or a copper alloy.

  In the cooling device manufacturing method according to the present invention, a plate-like member formed of a metal or an alloy is exposed to one surface of the cooling member formed of a metal or an alloy so that a part of the cooling member is exposed. A plate-shaped member arranging step to be arranged, an exposed portion where a part of the cooling member is exposed from the plate-shaped member, and at least a surface of the plate-shaped member around the exposed portion are made of a metal or an alloy. A heat conductive layer forming step of forming a heat conductive layer by accelerating the powder together with gas and spraying the powder in a solid state to deposit the powder.

  According to the present invention, since the cooling member and the plate-like member are separately manufactured, it is possible to select a material having good thermal conductivity as the cooling member and to select a material having high mechanical strength as the plate-like member. It becomes possible. Further, according to the present invention, the heat conduction layer is formed by the so-called cold spray method on the portion of the cooling member exposed from the plate-like member and the surrounding plate-like member surface, so that there is no intervening component that causes thermal resistance. The heat conductive layer can be formed directly on the cooling member, and at the same time, the cooling member and the plate-like member can be integrated. Therefore, it is possible to provide a cooling device that achieves both high mechanical strength of the mounting portion and good thermal conductivity of the cooling device itself.

FIG. 1 is a schematic diagram showing the structure of a cooling device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the cooling device shown in FIG. FIG. 3 is a flowchart showing a method of manufacturing the cooling device shown in FIG. FIG. 4 is a diagram for explaining a method of manufacturing the cooling device shown in FIG. FIG. 5 is a diagram for explaining a method of manufacturing the cooling device shown in FIG. FIG. 6 is a schematic diagram showing an outline of a cold spray apparatus. FIG. 7 is a cross-sectional view illustrating the structure of the cooling device according to the first modification. FIG. 8 is a cross-sectional view illustrating the structure of the cooling device according to the second modification. FIG. 9 is a cross-sectional view illustrating the structure of the cooling device according to the third modification. FIG. 10 is a top view illustrating the structure of the cooling device according to the fourth modification.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by the following embodiment. The drawings referred to in the following description only schematically show the shape, size, and positional relationship so that the contents of the present invention can be understood. That is, the present invention is not limited only to the shape, size, and positional relationship illustrated in each drawing.

(Embodiment)
FIG. 1 is a perspective view showing a structure of a cooling device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG.
As shown in FIGS. 1 and 2, the cooling device 1 according to the present embodiment includes a cooling member 11 provided with a heat medium channel 11 a for heat exchange in a member formed of metal or an alloy, and cooling. A plate-like member 12 disposed on one surface 11b of the member 11 (hereinafter also referred to as a plate-like member arrangement surface) and provided with an opening 12a exposing a part of the surface 11b, and the inside and surroundings of the opening 12a And a heat conductive layer 13 formed on the surface of the plate-like member 12.

  The cooling member 11 is formed of a member having good thermal conductivity, such as aluminum or an aluminum alloy. The channel 11a is provided by subjecting such a member to excavation and the like, for example, by forming a part into a fin shape, for example. The cooling member 11 radiates the heat conducted from the heat conductive layer 13 to a heat medium such as cooling water or cooling gas flowing through the flow path 11a.

  In addition, the shape of the flow path 11a is not limited to what is shown in FIG.1 and FIG.2, It is good also as a desired shape. Moreover, it is good also considering only the surface of the cooling member 11 as a thermal radiation part, without providing a flow path inside the cooling member 11. FIG.

  As a material for the cooling member 11, specifically, pure aluminum (A1000 series, thermal conductivity: 220 to 235 W / (m · K)) with Al of 99% or more, or an Al—Mg—Si based alloy (A6000 series). A6063 (thermal conductivity: 218 W / (m · K)) or the like subjected to annealing treatment) is used.

  The plate-like member 12 is formed of a metal or alloy having high mechanical strength such as an aluminum alloy. At least a part (all in FIG. 1) of the peripheral edge of the plate-like member 12 extends outward from the plate-like member arrangement surface 11b. This extended portion (extension portion) 12b is used as an attachment portion when the cooling device 1 is attached to, for example, a radiator that accommodates a heat medium.

  The size and shape of the opening 12a are not limited to those shown in FIG. 1, and may be a desired size and shape as long as they are within the plate-like member arrangement surface 11b. Preferably, the area of the opening 12a is set as wide as possible so that the mechanical strength of the plate-like member 12 can be secured and a space for forming the heat conductive layer 13 on the plate-like member 12 can be sufficiently secured. 11 and the heat conductive layer 13 are preferably widened.

Specifically, the material of the plate-like member 12 is a heat-treated Al-Cu alloy (A2000 series) (tensile strength: 330 to 490 MPa, proof stress: 250 to 290 MPa), Al-Mn alloy ( A3000 (working-hardened) (tensile strength: 150-220 MPa, proof stress: 130-200 MPa), Al-Mg alloy (A5000-based) work-hardened (tensile strength: 180-290 MPa, proof stress : 130-260 MPa), heat-treated Al-Mg-Si alloy (A6000 system) (tensile strength: 180-380 MPa, yield strength: 140-320 MPa), Al-Zn-Mg-Cu alloy (A7000) And the like subjected to heat treatment (tensile strength: 360 to 690 MPa, proof stress: 250 to 660 MPa).

  The heat conductive layer 13 is formed of a metal or alloy having good heat conductivity, such as copper or a copper alloy. The heat conductive layer 13 has a contact surface 13a that comes into contact with a heat generation source such as a chip directly or through a substrate or the like when the cooling device 1 is attached to a radiator or the like, and through the contact surface 13a. The received heat is conducted to the cooling member 11. Such a heat conductive layer 13 is formed by a so-called cold spray method in which a powder of material (copper powder or the like) is accelerated together with a gas and sprayed and deposited on a base material in a solid state. The heat conductive layer 13 is continuously provided over the exposed portion 11 c exposed from the opening 12 a and the upper surface of the plate member 12 around the opening 12 a, and the cooling member 11. And the plate-like member 12 are integrated with each other.

Next, a method for manufacturing the cooling device 1 will be described. FIG. 3 is a flowchart showing a method for manufacturing the cooling device 1.
First, in step S11, the cooling member 11 is produced by excavating aluminum or an aluminum alloy member into a desired shape (see FIG. 4).

  In the subsequent step S12, the plate-like member 12 is produced by providing an opening 12a in an aluminum alloy plate having a desired shape (see FIG. 4). At this time, in order to improve the mechanical strength of the plate member 12, the plate member 12 may be further subjected to heat treatment.

  In step S13, the plate member 12 is arranged on the plate member arrangement surface 11b of the cooling member 11 (see FIGS. 4 and 5). At this time, the plate member 12 may be temporarily fixed to the cooling member 11 using a jig, an adhesive, or the like.

  In step S14, the heat conductive layer 13 is formed by the cold spray method on the exposed portion 11c exposed from the opening 12a and the surface of the plate-like member 12 around the opening 12a in the plate-like member arrangement surface 11b.

  FIG. 6 is a schematic diagram showing an outline of a cold spray apparatus used for forming the heat conductive layer 13. As shown in FIG. 6, the cold spray device 60 contains a gas heater 61 that heats the compressed gas and a powder of the material of the heat conductive layer 13 (hereinafter referred to as “material powder” or simply “powder”). The supplied powder supply device 62, the gas nozzle 64 for injecting the heated compressed gas and the material powder supplied thereto onto the base 67, and the supply amount of the compressed gas to the gas heater 61 and the powder supply device 62 are adjusted. Valves 65 and 66 are provided.

As the compressed gas, helium, nitrogen, air or the like is used. The compressed gas supplied to the gas heater 61 is, for example, 50 ° C. or higher, heated to a temperature in a range lower than the melting point of the material powder, and then supplied to the spray gun 63. The heating temperature of the compressed gas is preferably 300 to 900 ° C.
On the other hand, the compressed gas supplied to the powder supply device 62 supplies the material powder in the powder supply device 62 to the spray gun 63 so as to have a predetermined discharge amount.

  The heated compressed gas is made a supersonic flow (about 340 m / s or more) by the gas nozzle 64 having a divergent shape. The gas pressure of the compressed gas at this time is preferably about 1 to 5 MPa. This is because the adhesion strength of the material powder to the base material 67 can be improved by adjusting the pressure of the compressed gas to this level. More preferably, the treatment is performed at a pressure of about 2 to 4 MPa. The material powder supplied to the spray gun 63 is accelerated by the injection of the compressed gas into the supersonic flow, and collides with the base material 67 at a high speed while being in a solid state, and forms a film. Note that the apparatus is not limited to the cold spray apparatus 60 shown in FIG. 6 as long as the apparatus can form a film by colliding the material powder toward the base material 67 in a solid state.

  In such a cold spray device 60, the cooling member 11 and the plate-like member 12 disposed thereon are set as the base material 67 to form a copper film (thermal conductive layer 13). At this time, a copper film is formed so as to be sufficiently thicker than the thickness of the plate member 12, and the copper film on the exposed portion 11 c and the copper film on the plate member 12 are integrated. Thereby, the cooling device 1 is completed.

  As described above, according to the present embodiment, the heat conductive layer 13 is formed in the opening 12a (exposed portion 11c) of the plate-like member 12 disposed on the cooling member 11 and around it by the cold spray method. . Here, the film formed by the cold spray method has high thermal conductivity because there is no phase transformation and oxidation is suppressed. Further, in the cold spray method, when the material powder collides with the base material (or the previously formed film), plastic deformation occurs between the powder and the base material, and an anchor effect is obtained. Since the coating is destroyed and metal bonds are formed between the new surfaces, the adhesive strength with the substrate is high. Therefore, since the heat conductive layer 13 itself has good heat conductivity and the heat conductive layer 13 is in close contact with the cooling member 11, good heat conductivity can be obtained between them.

  Moreover, according to this Embodiment, the material suitable for each function can be selected separately with the cooling member 11 and the plate-shaped member 12. FIG. Accordingly, the cooling device 1 can achieve both the thermal conductivity required for the cooling member 11 and the mechanical strength required for the plate-like member 12.

  Further, according to the present embodiment, since the cooling member 11 and the plate-like member 12 are integrated, it is not necessary to perform a heat treatment or the like for improving the mechanical strength of the plate-like member 12. 11 and the plate-like member 12 can suppress the formation of intermetallic compounds that cause thermal resistance.

  Moreover, in this Embodiment, the cooling member 11 and the plate-shaped member 12 are integrated by the heat conductive layer 13 formed by the cold spray method. Therefore, it is not necessary to separately provide a member or a process for fastening or joining the cooling member 11 and the plate-like member 12, and the number of parts can be reduced and the manufacturing process can be simplified.

  Hereinafter, modifications 1 to 4 of the present embodiment will be described. In addition, about the material of the cooling member in each modification 1-4, a plate-shaped member, and a heat conductive layer, it is the same as that of what was demonstrated in the said embodiment.

(Modification 1)
FIG. 7 is a cross-sectional view illustrating the structure of the cooling device according to the first modification. In the cooling device 2 shown in FIG. 7, the end surface 21 b of the opening 21 a provided in the plate-like member 21 has a tapered shape that spreads from the cooling member 11 side toward the upper surface of the plate-like member 21. In this case, since the level | step difference which arises in the area | region (plate-shaped member 21 around the exposed part 11c and the opening 21a) which sprays material powder when forming the heat conductive layer 13 can be reduced, it is more uniform in thickness and density. The heat conductive layer 13 can be formed. In FIG. 7, the heat conductive layer 13 is formed only on the exposed portion 11c and the end surface 21b. However, the heat conductive layer 13 may be extended to the upper surface of the plate-like member 21 around the end surface 21b.

(Modification 2)
FIG. 8 is a cross-sectional view illustrating the structure of the cooling device according to the second modification. In the cooling device 3 shown in FIG. 8, excavation is performed on the peripheral edge portion 31 b except for the portion corresponding to the opening 12 a of the upper surface (plate member arrangement surface) 31 a of the cooling member 31 by the amount corresponding to the thickness of the plate member 12. A cutout is provided. Thus, when the plate-like member 12 is disposed on the cooling member 31, the exposed portion 31 c is fitted into the opening 12 a, and the heights of the upper surface of the exposed portion 31 c and the upper surface of the plate-like member 12 are made uniform. In this case, the heat conductive layer 32 that is more uniform in thickness and density can be formed.

(Modification 3)
FIG. 9 is a cross-sectional view illustrating the structure of the cooling device according to the third modification.
In the cooling device 3 shown in FIG. 8, the exposed portion 31c of the cooling member 31 is fitted into the opening 12a without any gap. However, like the cooling device 4 shown in FIG. 9, the end surface of the exposed portion 31c and the opening 12a There may be a gap between the end face. In this case, when forming the heat conductive layer 41, the gap 41a between them is filled with a copper film, and the heat conductive layer 41 on the plate-like member 12 and the heat conductive layer 41 on the exposed portion 31c are integrated. You can do it.

  Further, as a further modification, at least one of the end face of the opening 12a and the end face of the exposed portion 31c may be tapered so as to expand toward the upper surface of the plate-like member 12 as in the second modification.

(Modification 4)
FIG. 10 is a top view illustrating the structure of the cooling device according to the fourth modification.
In the embodiment and the first to third modifications described above, the plate-like member provided with the opening is disposed on the cooling member. However, it is not always necessary to provide an opening in the plate member as long as a part of the plate member arrangement surface of the cooling member can be exposed when the plate member is arranged.

  For example, like the cooling device 5 shown in FIG. 10, by arranging the plate-like members 52 and 53 on the plate-like member arrangement surface of the cooling member 51 so as to be spaced apart from each other, a part of the plate-like member arrangement surface is formed. Can be exposed. In this case, the cooling member 51 and the plate-like members 52 and 53 are simultaneously formed by forming the heat conductive layer 54 by the cold spray method from the exposed portion 51a of the plate-like member arrangement surface to the plate-like members 52 and 53. Can be integrated.

  In the fourth modification, as in the first modification, the end surfaces of the plate-like members 52 and 53 may be tapered. Further, similarly to the second and third modifications, a cutout may be provided on the upper surface of the cooling member 51 and the plate-like members 52 and 53 may be fitted into the cutout.

1-5 Cooling device 11, 31, 51 Cooling member 11a Flow path 11b Plate-like member arrangement surface 11c, 31c, 51a Exposed portion 12, 21, 52 Plate-like member 12a, 21a Opening 13, 32, 41, 54 Thermal conduction layer 13a Contact surface 21b End surface 31b Peripheral portion 41a Clearance 60 Cold spray device 61 Gas heater 62 Powder supply device 63 Spray gun 64 Gas nozzle 65, 66 Valve 67 Base material

Claims (8)

A cooling member formed of metal or alloy;
A plate-like member that is formed of a metal or an alloy and disposed on one surface of the cooling member such that a part of the cooling member is exposed;
A powder made of a metal or an alloy is accelerated together with a gas toward an exposed portion where a part of the cooling member is exposed from the plate-like member, and at least the surface of the plate-like member around the exposed portion, and a solid phase A thermally conductive layer formed by spraying as it is to deposit the powder;
A cooling device comprising:   The cooling device according to claim 1, wherein an opening for exposing a part of the cooling member is formed in the plate member.   3. The cooling device according to claim 1, wherein at least a part of the plate-like member extends outside the outer periphery of the cooling member.   The end face of the plate-shaped member that contacts the boundary of the exposed portion has a tapered shape that widens from the cooling member side toward the surface of the plate-shaped member. The cooling device as described.   The plate-like member arrangement surface of the cooling member is provided with a notch that is equal to the thickness of the plate-like member and into which the plate-like member is fitted. 2. The cooling device according to item 1.   The cooling device according to any one of claims 1 to 5, wherein the cooling member is provided with a flow path of a heat medium. The cooling member is formed of aluminum or an aluminum alloy,
The plate-like member is formed of an aluminum alloy,
The cooling device according to claim 1, wherein the heat conductive layer is made of copper or a copper alloy. A plate-like member arranging step of arranging a plate-like member formed of a metal or an alloy so that a part of the cooling member is exposed with respect to one surface of the cooling member formed of a metal or an alloy;
A powder made of a metal or an alloy is accelerated together with a gas toward an exposed portion where a part of the cooling member is exposed from the plate-like member, and at least the surface of the plate-like member around the exposed portion, and a solid phase A thermal conductive layer forming step of forming a thermal conductive layer by depositing the powder by spraying in a state; and
The manufacturing method of the cooling device characterized by including this.

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