CN114078793A - Cooling device and method for manufacturing cooling device - Google Patents

Cooling device and method for manufacturing cooling device Download PDF

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Publication number
CN114078793A
CN114078793A CN202110865418.9A CN202110865418A CN114078793A CN 114078793 A CN114078793 A CN 114078793A CN 202110865418 A CN202110865418 A CN 202110865418A CN 114078793 A CN114078793 A CN 114078793A
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CN
China
Prior art keywords
heat sink
cooling device
flat plate
case
fins
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Pending
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CN202110865418.9A
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Chinese (zh)
Inventor
安西智洋
伊川俊辅
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Lishennoco Co ltd
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Showa Denko KK
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Publication of CN114078793A publication Critical patent/CN114078793A/en
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K7/00—Constructional details common to different types of electric apparatus
    • H05K7/20—Modifications to facilitate cooling, ventilating, or heating
    • H05K7/20218—Modifications to facilitate cooling, ventilating, or heating using a liquid coolant without phase change in electronic enclosures
    • H05K7/20254—Cold plates transferring heat from heat source to coolant
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/46—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements involving the transfer of heat by flowing fluids
    • H01L23/473—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements involving the transfer of heat by flowing fluids by flowing liquids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/20—Bonding
    • B23K26/21—Bonding by welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/70—Auxiliary operations or equipment
    • B23K26/702—Auxiliary equipment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
    • H01L21/4814—Conductive parts
    • H01L21/4871—Bases, plates or heatsinks
    • H01L21/4882—Assembly of heatsink parts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2101/00—Articles made by soldering, welding or cutting
    • B23K2101/04—Tubular or hollow articles
    • B23K2101/14—Heat exchangers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
    • H01L23/3735—Laminates or multilayers, e.g. direct bond copper ceramic substrates

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Engineering (AREA)
  • Plasma & Fusion (AREA)
  • Manufacturing & Machinery (AREA)
  • Thermal Sciences (AREA)
  • Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
  • Cooling Or The Like Of Electrical Apparatus (AREA)
  • Laser Beam Processing (AREA)

Abstract

The invention provides a cooling device which can be manufactured without reducing the strength of components and a manufacturing method of the cooling device. The cooling device is provided with: a heat sink (10) having a flat plate-like portion (11) and a plurality of fins (12) protruding from the flat plate-like portion (11); and a cover (22) that houses the heat sink (10), wherein the heat sink (10) is joined to the cover (22) by irradiating the flat plate-shaped portion (11) between the plurality of fins (12) with laser light (L) from the side of the plurality of fins (12).

Description

Cooling device and method for manufacturing cooling device
Technical Field
The present invention relates to a cooling device and a method for manufacturing the cooling device.
Background
For example, a cooler described in patent document 1 is formed by housing a fin unit in a base body formed of a1 st base body forming member and a 2 nd base body forming member. An inner region through which a heat-supplying medium flows is formed inside the base. The surface of the 1 st base forming member opposite to the inner region is set as the 1 st surface to which the power module as a heat generating body is bonded. The surface of the 2 nd base forming member opposite to the inner region is set as the 2 nd surface to which the power module is bonded. The fin unit is formed by forming columnar fins on both surfaces of a flat plate-shaped substrate. The fin unit is formed by integrally molding the base plate and the fins. Specifically, the fin unit is formed by hot forging an aluminum plate and/or a copper plate using a forging die formed in accordance with the shape of the fin unit. The first substrate-forming member 1 and the second substrate-forming member 2 are formed by collectively brazing the surfaces on the inner region side with a brazing material applied thereto, and the tip end surfaces of the fins in the fin unit are in contact with the brazing material applied to the first substrate-forming member 1 and the second substrate-forming member 2.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2013-239675
Disclosure of Invention
Problems to be solved by the invention
After a plurality of components are formed, if Brazing (Brazing) is performed to join the components, the entire product may be annealed and have a reduced strength.
The invention aims to provide a cooling device and the like which can be manufactured without reducing the strength of components.
Means for solving the problems
The present invention accomplished to achieve the above object is a cooling device including: a heat sink having a flat plate-like portion and a plurality of fins protruding from the flat plate-like portion; and a case that houses the heat sink, wherein the heat sink is bonded to the case by irradiating the flat plate-shaped portion between the plurality of fins with laser light from the fin side.
Here, the flat plate-shaped portion and the case may be formed with a fusion portion.
In addition, a fusion zone may be formed in the flat plate-like portion, the fin, and the case.
The case may have a case body having a bottomed concave shape, and a cover that covers an opening of the case body and holds the heating element on a side opposite to the case body, and the heat sink may be joined to a portion of the cover on the side opposite to the heating element.
The case may have a case body having a bottomed concave shape and a cover covering an opening of the case body, the heat generating element may be held on a bottom portion of the case body on a side opposite to the cover, and the heat sink may be joined to a portion of the bottom portion of the case body on the side opposite to the heat generating element.
Further, a surface of the fin facing an adjacent fin may be inclined with respect to the protruding direction such that a distance between the adjacent fins gradually decreases from the distal end portion to the base end portion.
Further, the fin may have at least one of a chamfer and an R portion at a tip end portion.
In addition, the heat sink may be formed of aluminum or copper.
In addition, a portion of the case to which the heat sink is joined may be molded from at least one of aluminum and copper.
Further, the heat sink may be molded from aluminum, a portion of the case to which the heat sink is joined may be molded from a clad material of aluminum and copper, and the aluminum may be a joining surface to which the heat sink is joined.
In addition, the present invention is a cooling device, as viewed from another point of view, comprising: a heat sink having a flat plate-like portion and a plurality of fins protruding from the flat plate-like portion; and a base that holds the heat sink and that holds the heating element on the side opposite to the heat sink, wherein the heat sink is bonded to the base by irradiating the flat plate-shaped portion between the plurality of fins with laser light from the fin side.
In addition, the present invention is a method of manufacturing a cooling device, in which a heat sink having a flat plate-like portion and a plurality of fins protruding from the flat plate-like portion is overlapped with a case housing the heat sink, and the flat plate-like portion between the plurality of fins is irradiated with laser light from the fin side, thereby joining the heat sink to the case.
In addition, the present invention is a method of manufacturing a cooling device, in which a heat sink having a flat plate-like portion and a plurality of fins protruding from the flat plate-like portion and a base holding a case holding the heat sink and a heating element on a side opposite to the heat sink are overlapped, and the flat plate-like portion between the plurality of fins is irradiated with laser light from the side of the plurality of fins, thereby joining the heat sink and the base.
Effects of the invention
According to the present invention, a cooling device and the like can be provided which can be manufactured without reducing the strength of the component.
Drawings
Fig. 1 is an example of an exploded view of components constituting a cooling device according to embodiment 1.
Fig. 2 is a view showing an example of a cross section of the cooling device.
Fig. 3 is a diagram for explaining the joining of the heat sink and the cover.
Fig. 4 is a diagram illustrating an example of the welded portion.
Fig. 5 is a diagram illustrating an example of the welding path.
Fig. 6 is a diagram showing an example of a welding path when the heat sink having the corrugated fin is joined to the cover.
Fig. 7 is a diagram showing an example of a modification of the shape of the fin.
Fig. 8 is a diagram illustrating an example of a welded portion according to embodiment 2.
Fig. 9 is a diagram showing an example of a cross section of the cooling device according to embodiment 3.
Fig. 10 is a diagram showing an example of a cross section of the cooling device according to embodiment 4.
Description of the reference numerals
1, 2, 3, 4 … cooling device, 5 … semiconductor module, 10 … heat sink, 11 … flat plate portion, 12 … fin, 20 … case, 21 … case main body, 22 … cover, 31 … bottom, 40 … welding portion, 41 … melting portion, 121 … front end portion, 122 … base end portion, 123 … chamfer, 60 … base, 151 … laser head, L … laser head
Detailed Description
Hereinafter, embodiments will be described in detail with reference to the drawings.
< embodiment 1 >
Fig. 1 is an example of an exploded view of components constituting a cooling device 1 according to embodiment 1.
Fig. 2 is a diagram showing an example of a cross section of the cooling apparatus 1.
The cooling device 1 of the embodiment includes: a heat sink 10 having fins 12; and a case 20 that houses the radiator 10 and forms a space through which the cooling liquid flows. The cooling device 1 is a liquid-cooled cooling device that cools the semiconductor module 5, which is an example of a heat generating body, using a cooling liquid and a heat sink 10.
The case 20 includes a case body 21 having a bottomed concave shape, a cover 22 covering an opening of the case body 21, an O-ring 23 sealing a space between the case body 21 and the cover 22, and a bolt 24 joining the case body 21 and the cover 22. The housing 20 includes an inflow pipe 25 for allowing the coolant to flow into the housing 20, and an outflow pipe 26 for allowing the coolant to flow out of the housing 20.
The material of the case body 21 and the cover 22 may be, for example, a6000 series aluminum alloy such as a6063 or copper.
The case body 21 has a flat rectangular bottom portion 31 and 4 side walls 32 protruding from peripheral end portions of the bottom portion 31 in a direction orthogonal to the plate surface of the bottom portion 31.
The 1 st through-hole 323 penetrating the 1 st sidewall 321 is formed in the 1 st sidewall 321 among the 4 sidewalls 32. In addition, a 2 nd through hole 324 penetrating the 2 nd side wall 322 is formed in the 2 nd side wall 322 opposed to the 1 st side wall 321 among the 4 side walls 32. The inflow tube 25 is fitted into the 1 st through hole 323, and the outflow tube 26 is fitted into the 2 nd through hole 324.
Further, on the end surface of the 4 side walls 32 on the cover 22 side, a groove 325 into which the O-ring 23 is fitted is formed around the opening of the housing body 21, and female screws 326 for fastening the bolts 24 are formed at four corners outside the groove 325.
The cover 22 is a flat plate-like member. Holes 221 through which the bolts 24 are inserted are formed at four corners of the cover 22.
The heat sink 10 is joined to an inner surface 222 of the cover 22 on the side of the housing body 21. The joining method thereof will be described in detail later.
On the other hand, the semiconductor module 5 is joined to an outer surface 223 that is the surface of the cover 22 opposite to the inner surface 222.
Here, the semiconductor module 5 has an insulating substrate 51, a wiring layer 52 provided on the insulating substrate 51, and a semiconductor element 53 mounted on the wiring layer 52 via a solder layer 54. The semiconductor module 5 further includes a heat transfer layer 55 for transferring heat from the insulating substrate 51 to the cooling device 1.
The heat transfer layer 55 of the semiconductor module 5 is joined to the outer surface 223 of the cover 22. Examples of a method for joining the heat transfer layer 55 and the cover 22 include brazing, soldering, sintering (sintering), bonding with a resin, and adhesion with a thermal conductive paste.
The heat sink 10 includes a flat plate-like portion 11 and a plurality of columnar fins 12 projecting from the flat plate-like portion 11 in a direction orthogonal to the plate surface.
The fins 12 may be exemplified by a columnar shape in which the protruding direction from the flat plate-like portion 11 is a columnar direction. The shape of the fin 12 when viewed from the projecting direction (hereinafter, sometimes referred to as "cross-sectional shape") may be exemplified by a circle or an ellipse. The cross-sectional shape may be a square, a rectangle, a rhombus, or the like. The fin 12 may be flat. When the fins 12 are flat, they may be parallel to the direction from the inlet pipe 25 toward the outlet pipe 26, or may be wavy with portions inclined with respect to the direction from the inlet pipe 25 toward the outlet pipe 26.
The heat sink 10 may be formed by forging, for example. The material of the heat sink 10 may be, for example, a 1000-series pure aluminum such as a1100, or copper.
The cooling device 1 and the semiconductor module 5 configured as described above are assembled as follows.
First, the cover 22 and the semiconductor module 5 are brazed.
After that, the cover 22 to which the semiconductor module 5 is bonded to the heat sink 10 by laser welding. Details regarding this engagement will be described later.
Next, the cover 22 to which the heat sink 10 is bonded is covered on the case main body 21 so that the semiconductor module 5 is positioned outside and the heat sink 10 is housed inside the case 20, and the opening of the case main body 21 is covered with the cover 22. When the cover 22 is to be covered on the housing body 21, the O-ring 23 is fitted in advance in the groove 325 formed in the housing body 21.
After the cover 22 is placed on the case main body 21, the bolt 24 inserted through the hole 221 formed in the cover 22 is fastened to the female screw 326 formed in the case main body 21.
Thereby, a circulation space 35 through which the coolant flows is formed in a space surrounded by the heat sink 10 and the recess 34 of the case main body 21. The flow-through space 35 is sealed by an O-ring 23.
Next, a method of joining the radiator 10 to the cover 22 will be described.
Fig. 3 is a diagram for explaining the joining of the heat sink 10 and the cover 22.
Fig. 4 is a diagram illustrating an example of the welded portion 40.
As shown in fig. 3, the cover 22 is superimposed on the heat sink 10 such that the flat plate-like portion 11 of the heat sink 10 is placed on the cover 22 in contact therewith. Then, the laser head 151 of the laser device 150 irradiates the flat plate-like portion 11 between the plurality of fins 12 from the side of the plurality of fins 12 of the heat sink 10 with the laser light L. Then, the laser heads 151 are moved along the shape of the gaps between the plurality of fins 12, thereby continuously irradiating the laser light L.
When the flat plate portion 11 of the heat sink 10 is irradiated with the laser light L, the energy of the laser light L is converted into heat, whereby the flat plate portion 11 of the heat sink 10 and the base material of the cover 22 are melted and then rapidly cooled. The welded portion 40 is subjected to structural change by the rapid heating and rapid cooling, and the welded portion 40 is composed of a molten portion 41 that is melted and then solidified, and a heat-affected zone 42 in which the structural change is caused by the welding heat. The heat-affected zone 42 is composed of the heat-affected zone 42h of the flat plate-like portion 11 and the heat-affected zone 42c of the cover 22.
In the present embodiment, laser welding is performed so that the melting portion 41 does not penetrate the cover 22. This is to suppress the occurrence of irregularities on the outer surface 223 of the cover 22 to which the semiconductor module 5 is bonded, due to the penetration of the melting portion 41 through the cover 22. The energy density per unit time may be adjusted so that the fusion zone 41 does not penetrate the cover 22 for laser welding. Since the deeper fusion zone 41 is formed as the energy density per unit time becomes higher, the energy density per unit time becomes lower than the energy density per unit time when penetrating through the cover 22. In order to reduce the energy density per unit time, the moving speed of the laser head 151 may be increased. In addition, in order to reduce the energy density per unit time, the laser output may be reduced. Therefore, by at least one of increasing the moving speed of the laser torch 151 and reducing the laser output, the laser welding can be performed so that the melting portion 41 does not penetrate the cover 22.
The cooling device 1 configured as described above includes: a heat sink 10 having a flat plate-like portion 11 and a plurality of fins 12 protruding from the flat plate-like portion 11; and a case 20 that houses the heat sink 10, forms a flow space 35 as an example of a space through which the cooling liquid flows, and irradiates the flat plate-shaped portion 11 between the plurality of fins 12 with the laser light L from the side of the plurality of fins 12, thereby bonding the heat sink 10 to the case 20. Thus, for example, in comparison with a configuration in which the radiator 10 and the case 20 are joined by brazing, since annealing of the entire cooling device 1 does not occur at the time of brazing, it is possible to suppress a decrease in strength of the case main body 21 and/or the cover 22 due to annealing. Further, since the heat sink 10 and the case 20 are joined by irradiating the laser light L from the fin 12 side of the heat sink 10, the case 20 can be prevented from being formed with irregularities, as compared with the configuration in which the heat sink 10 and the case 20 are joined by irradiating the laser light L from the case 20 side.
Here, the case 20 includes a case main body 21 having a bottomed concave shape, and a cover 22 that covers an opening portion of the case main body 21 and holds the semiconductor module 5 on a side opposite to the case main body 21, and the heat sink 10 is joined to an inner surface 222 of the cover 22, which is an example of a portion opposite to the semiconductor module 5. By irradiating the laser light L from the fin 12 side of the heat sink 10, it is possible to suppress the occurrence of irregularities on the surface of the portion of the cover 22 holding the semiconductor module 5 due to the formation of the welded portion in the portion. For example, when the laser L is irradiated to the outer surface 223 of the cover 22 to join the heat sink 10 and the cover 22, a welded portion is formed on the outer surface 223 of the cover 22 to form irregularities. If the gap between the cover 22 and the semiconductor module 5 becomes large due to the irregularities, heat from the semiconductor module 5 may not be efficiently transferred to the cover 22, and cooling performance may deteriorate. In addition, when the heat transfer layer 5 is made of, for example, a heat conductive paste, it is necessary to increase the amount of the heat conductive paste used to fill the gap between the cover 22 and the semiconductor module 5. In order to prevent this, if the outer surface 223 of the cover 22 is cut to have a flat surface so as to eliminate the unevenness of the welded portion, the number of manufacturing steps increases, and thus the manufacturing cost increases. In the cooling device 1 of the above embodiment, since the surface of the cover 22 where the semiconductor module 5 is held is less likely to have irregularities, it is possible to suppress deterioration of the cooling performance and increase in cost due to the irregularities.
Fig. 5 is a diagram illustrating an example of the welding path.
As shown in fig. 5, the laser light L is irradiated so that the welded portions 40 are formed between all the adjacent fins 12 among the plurality of fins 12 having the rhombic cross-sectional shape. Further, when the laser light L is irradiated, the laser head 151 is moved so as to reciprocate in the same direction. For example, the irradiation operation is repeated in which the laser heads 151 are moved in the 1 st direction M1 from the lower left to the upper right in fig. 5 and in the 2 nd direction M2 from the upper right to the lower left. When the laser torch reaches the right end portion, the irradiation operation is repeated in which the laser torch 151 is moved in the 3 rd direction M3 from the lower right to the upper left, and in the 4 th direction M4 from the upper left to the lower right.
This enables the welded portion 40 to be molded quickly and accurately.
Fig. 6 is a diagram showing an example of a welding path when the heat sink 10 having the corrugated fin 12 is joined to the cover 22.
Even if the fins 12 are corrugated, the laser light L is irradiated so that the welded portions 40 are formed between all the adjacent fins 12 among the plurality of fins 12. For example, the irradiation operation is repeated in which the laser head 151 is moved in the 5 th direction M5 from the left to the right in fig. 6 and the irradiation operation is performed in the 6 th direction M6 from the right to the left.
This enables the welded portion 40 to be molded quickly and accurately.
(materials of radiator 10 and cover 22)
The materials of the heat sink 10 and the cover 22 can be exemplified as follows.
In other words, the heat sink 10 and the cover 22 are made of the same material, and are made of copper or aluminum. Further, the heat sink 10 and the cover 22 are made of different materials, and one of them is made of copper and the other is made of aluminum. For example, since the heat sink 10 is made of aluminum and the cover 22 is made of copper, the heat sink 10 can be easily molded by forging, and the heat conductivity of the cover 22 can be improved, so that the cooling performance of the cooling device 1 can be improved.
The heat sink 10 may be molded of aluminum, and the cover 22 may be molded of a clad material of aluminum and copper, which serves as a bonding surface with the heat sink 10. Thus, the heat sink 10 can be easily molded by forging, and the portion of the cover 22 to which the heat sink 10 is joined is made of aluminum as in the case of the heat sink 10, so that joining can be easily performed by laser welding. Further, since the portion of the cover 22 to which the semiconductor module 5 is bonded is made of copper, heat from the semiconductor module 5 can be rapidly transferred to the heat sink 10, and thus the cooling performance of the cooling device 1 can be improved.
(modification of shape of fin 12)
Fig. 7 is a diagram showing an example of a modification of the shape of the fin 12.
As shown in fig. 7, the fins 12 may be formed as follows: the surfaces of the fins 12 facing the adjacent fins 12 are inclined with respect to the protruding direction so that the distance between the adjacent fins 12 gradually decreases from the distal end 121 to the base end 122. This can suppress the laser beam L irradiated between the adjacent fins 12 from striking the fins 12.
In addition, as shown in fig. 7, the fin 12 may have a chamfer 123 at the leading end portion 121. This can suppress the laser beam L irradiated between the adjacent fins 12 from reaching the distal end portion 121. Instead of the chamfer 123, the fin 12 may have an R portion in which the corner of the tip portion 121 of the fin 12 is rounded. Even in the R portion, the laser light L can be prevented from reaching the distal end portion 121. The fin 12 may have an R portion at a corner of the chamfer 123.
< embodiment 2 >
The cooling apparatus 2 according to embodiment 2 differs from the cooling apparatus 1 according to embodiment 1 in the shape of the welded portion 40. The following description deals with differences from embodiment 1. The same reference numerals are used for portions having the same functions in embodiment 1 and embodiment 2, and detailed description thereof is omitted.
Fig. 8 is a diagram illustrating an example of the welded portion 240 according to embodiment 2.
The welded portion 240 of embodiment 2 is different from embodiment 1 in that the fused portions 241 are formed in the flat plate-like portion 11, the base end portion 122 of the fin 12, and the cover 22, and the fused portions 41 are not formed in the welded portion 40 of embodiment 1 in the fin 12. In other words, the laser welding is performed so that the melted portion 241 is formed on the flat plate portion 11, the base end portion 122 of the fin 12, and the cover 22. In order to perform laser welding so that the melted portion 241 is also formed on the base end portion 122 of the fin 12, the energy density per unit time may be increased as compared with the formation of the welded portion 40 of embodiment 1. In order to increase the energy density per unit time, the moving speed of the laser head 151 may be decreased. In addition, in order to increase the energy density per unit time, the laser output may be increased. Therefore, by at least one of reducing the moving speed of the laser torch 151 and increasing the laser output, the laser welding can be performed so that the melted portion 241 is also formed on the base end portion 122 of the fin 12.
Further, by forming the melted portion 241 also in the base end portion 122 of the fin 12 in this manner, the width W of the melted portion 241 at the joint interface between the heat sink 10 and the cover 22 can be increased as compared with the melted portion 41 in which the melted portion is not formed in the base end portion 122 of the fin 12. As a result, the heat conductivity between the radiator 10 and the cover 22 can be improved, and therefore, the cooling performance can be improved.
< embodiment 3 >
The cooling device 3 according to embodiment 3 differs from the cooling device 1 according to embodiment 1 in that the heat sink 10 is joined to the case main body 21. The following description deals with points different from embodiment 1. The same reference numerals are used for portions having the same functions in embodiment 1 and embodiment 3, and detailed description thereof is omitted.
Fig. 9 is a diagram showing an example of a cross section of the cooling device 3 according to embodiment 3.
In the cooling device 3, the semiconductor module 5 is joined to the bottom portion 31 of the case main body 21 on the side opposite to the cover 22. The heat sink 10 is joined to the bottom surface 311, which is a portion of the bottom portion 31 of the case main body 21 on the side opposite to the semiconductor module 5.
The method of joining the heat sink 10 and the case main body 21 is the same as the method of joining the heat sink 10 and the cover 22 described with reference to fig. 3. That is, the case body 21 is superimposed on the heat sink 10 so that the flat plate-like portion 11 of the heat sink 10 is placed on the bottom surface 311 of the case body 21 in contact therewith. Then, the flat plate-shaped portion 11 between the plurality of fins 12 is irradiated with the laser light L from the side of the plurality of fins 12 of the heat sink 10.
In the present embodiment, laser welding is performed so that the melted portion formed by irradiation with the laser light L does not penetrate the case main body 21. This is to suppress the occurrence of irregularities on the outer surface 211 of the case main body 21 to which the semiconductor module 5 is joined, due to the melted portion penetrating the case main body 21.
The fusion zone of embodiment 3 may be formed in the flat plate-like portion 11 and the case main body 21 of the heat sink 10 as in the fusion zone 41 of embodiment 1, or may be formed in the flat plate-like portion 11, the base end portions 122 of the fins 12, and the case main body 21 of the heat sink 10 as in the fusion zone 241 of embodiment 2.
The cooling device 3 and the semiconductor module 5 configured as described above can be assembled as follows.
First, the semiconductor module 5 and the case main body 21 are brazed.
After that, the case main body 21 to which the semiconductor module 5 is bonded to the heat sink 10 by laser welding.
Next, the cover 22 is covered on the case main body 21, and the bolt 24 inserted through the hole 221 formed in the cover 22 is fastened to the female screw 326 formed in the case main body 21. When the cover 22 is placed on the housing body 21, the O-ring 23 is fitted into the groove 325 formed in the housing body 21.
With the cooling device 3 configured as described above, compared with a configuration in which the radiator 10 and the case main body 21 are joined by brazing, annealing of the entire cooling device 3 does not occur at the time of brazing, and therefore, it is possible to suppress a decrease in strength of the case main body 21 and/or the cover 22 due to annealing. Further, since the heat sink 10 and the case main body 21 are joined by irradiating the laser light L from the fin 12 side of the heat sink 10, it is possible to suppress formation of irregularities on the outer surface 211 of the case main body 21, compared to a configuration in which the heat sink 10 and the case main body 21 are joined by irradiating the laser light L from the case main body 21 side. That is, in the cooling device 3, since the irregularities are less likely to be generated on the outer surface 211, which is the surface of the case main body 21 where the semiconductor module 5 is held, it is possible to suppress the deterioration of the cooling performance and the increase in cost due to the generation of the irregularities described above.
< embodiment 4 >
The cooling device 4 of embodiment 4 is an air-cooling type cooling device that cools the semiconductor module 5, which is an example of a heat generating body, using air and a heat sink 10, and is different from the cooling device 1 of embodiment 1. The following description deals with points different from embodiment 1. The same reference numerals are used for portions having the same functions in embodiment 1 and embodiment 4, and detailed description thereof is omitted.
Fig. 10 is a diagram showing an example of a cross section of the cooling device 4 according to embodiment 4.
The cooling device 4 includes a radiator 10 and a base 60 that holds the radiator 10.
The base 60 is a flat plate-like member. Holes 60h are formed in the base 60, for example, at four corners, for inserting bolts 64, the bolts 64 being attached to a product to which the cooling device 4 is to be attached.
In the base 60, the heat sink 10 is joined to the 1 st surface 61, which is one surface, and the semiconductor module 5 is joined to the 2 nd surface 62, which is the other surface, in the same manner as the cover 22 of embodiment 1.
The method of bonding the semiconductor module 5 to the base 60 is the same as the method of bonding the semiconductor module 5 to the cover 22 in embodiment 1.
The method of joining the heat sink 10 to the base 60 is the same as the method of joining the heat sink 10 to the cover 22 in embodiment 1. That is, the base 60 is superimposed on the heat sink 10 so that the flat plate-like portion 11 of the heat sink 10 is placed on the 1 st surface 61 of the base 60 in contact therewith. Then, the flat plate-shaped portion 11 between the plurality of fins 12 is irradiated with the laser light L from the side of the plurality of fins 12 of the heat sink 10.
In the present embodiment, laser welding is performed so that the melted portion formed by irradiation with the laser light L does not penetrate the base 60. This is to suppress the occurrence of irregularities on the 2 nd surface 62 of the base 60 to which the semiconductor module 5 is bonded, due to the melted portion penetrating through the base 60.
The fusion zone of embodiment 4 may be formed on the flat plate-shaped portion 11 and the base 60 of the heat sink 10, as in the fusion zone 41 of embodiment 1, or may be formed on the flat plate-shaped portion 11, the base end portion 122 of the fin 12, and the base 60 of the heat sink 10, as in the fusion zone 241 of embodiment 2.
With the cooling device 4 configured as described above, compared with a configuration in which the heat sink 10 and the base 60 are joined by brazing, annealing of the entire cooling device 4 does not occur at the time of brazing, and therefore, a decrease in strength of the base 60 due to annealing can be suppressed. Further, since the heat sink 10 is joined to the base 60 by irradiating the laser light L from the fin 12 side of the heat sink 10, it is possible to suppress formation of irregularities on the 2 nd surface 62 of the base 60, compared to a configuration in which the heat sink 10 is joined to the base 60 by irradiating the laser light L from the base 60 side. That is, in the cooling device 4, since the unevenness is less likely to occur on the 2 nd surface 62 which is the surface of the base 60 where the semiconductor module 5 is held, it is possible to suppress the deterioration of the cooling performance and the increase in cost due to the occurrence of the unevenness as described above.

Claims (13)

1. A cooling device is provided with:
a heat sink having a flat plate-like portion and a plurality of fins protruding from the flat plate-like portion; and
a case that houses the heat sink,
the heat sink is bonded to the case by irradiating the flat plate-shaped portion between the plurality of fins with laser light from the fin side.
2. The cooling device according to claim 1,
a fusion portion is formed between the flat plate portion and the case.
3. The cooling device according to claim 1,
a melting portion is formed in the flat plate-like portion, the fin, and the case.
4. The cooling device according to any one of claims 1 to 3,
the case has a case body having a bottomed concave shape, and a cover which covers an opening of the case body and holds the heating element on a side opposite to the case body,
the heat sink is joined to a portion of the cover on the side opposite to the heating element.
5. The cooling device according to any one of claims 1 to 3,
the case has a case body having a bottomed concave shape and a cover covering an opening of the case body, and a heating element is held on a side opposite to the cover of a bottom of the case body,
the heat sink is joined to a portion of the bottom of the case main body on the side opposite to the heating element.
6. The cooling device according to any one of claims 1 to 3,
the surface of the fin facing the adjacent fin is inclined with respect to the protruding direction so that the distance between the adjacent fins gradually decreases from the distal end portion to the base end portion.
7. The cooling device according to any one of claims 1 to 3,
the fin has at least one of a chamfer and an R portion at a front end portion.
8. The cooling device according to any one of claims 1 to 3,
the heat sink is formed of aluminum or copper.
9. The cooling device according to any one of claims 1 to 3,
a portion of the case to which the heat sink is joined is molded from at least any one of aluminum and copper.
10. The cooling device according to any one of claims 1 to 3,
the heat sink is formed of aluminum and is,
the portion of the case to which the heat sink is joined is molded from a clad material of aluminum and copper, and the aluminum serves as a joining surface with the heat sink.
11. A cooling device is provided with:
a heat sink having a flat plate-like portion and a plurality of fins protruding from the flat plate-like portion; and
a base that holds the heat sink and holds a heat-generating body on a side opposite to the heat sink,
the heat sink is bonded to the base by irradiating the flat plate-shaped portion between the plurality of fins with laser light from the fin side.
12. A method of manufacturing a cooling device, in which a heat sink having a flat plate-like portion and a plurality of fins projecting from the flat plate-like portion is superposed on a case housing the heat sink,
the heat sink is joined to the case by irradiating the flat plate-like portion between the plurality of fins with laser light from the plurality of fins.
13. A method of manufacturing a cooling device, wherein a heat sink having a flat plate-like portion and a plurality of fins projecting from the flat plate-like portion is superposed on a base which holds a case for holding the heat sink and holds a heating element on the side opposite to the heat sink,
the heat sink is joined to the base by irradiating the flat plate-like portion between the plurality of fins with laser light from the plurality of fins.
CN202110865418.9A 2020-08-21 2021-07-29 Cooling device and method for manufacturing cooling device Pending CN114078793A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2020-140331 2020-08-21
JP2020140331A JP2022035781A (en) 2020-08-21 2020-08-21 Cooler and manufacturing method therefor

Publications (1)

Publication Number Publication Date
CN114078793A true CN114078793A (en) 2022-02-22

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Application Number Title Priority Date Filing Date
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JP (1) JP2022035781A (en)
CN (1) CN114078793A (en)
DE (1) DE202021103562U1 (en)

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JP2022035781A (en) 2022-03-04
DE202021103562U1 (en) 2021-07-15

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