JP2018049861A - Semiconductor device and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of components, and thereby reduce a manufacturing cost.SOLUTION: In a cooling device for a semiconductor device, a lower housing part 33 configured by integrally molding a housing part 331 and fixing parts 334a-334d by a casting method using a material whose liquidus temperature is equal to or higher than a brazing temperature, an upper lid, and a heat dissipation fin part 31, are integrally molded by brazing. Further, a thermal conductivity of the material is equal to or more than 150 W/(mK). Such the cooling device can reduce the number of components, and thereby reduce a manufacturing cost, and can suppress reduction in heat dissipation property.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a semiconductor device and a method for manufacturing the semiconductor device.

  In order to maintain the reliability of the semiconductor module including the power semiconductor element, the power semiconductor element can be efficiently and stably cooled by mounting the semiconductor module on the cooling device.

  The cooling device, for example, introduces a refrigerant from a piping part attached to the inlet, circulates the refrigerant between a plurality of heat dissipating fins arranged inside the cooling device, and receives the refrigerant from the piping part attached to the outlet. The refrigerant circulates to be discharged. The heat generated from the semiconductor module is dissipated through the refrigerant circulating in the cooling device, thereby cooling the power semiconductor element.

Japanese Patent Laid-Open No. 2005-079386

  However, the cooling device is composed of an upper lid on which a semiconductor module is mounted, a heat radiation fin, and a housing part that houses the heat radiation fin and forms a flow path, and further, a piping part is provided between the inlet and the outlet. Each of them is joined to be composed of a plurality of articles.

  The present invention has been made in view of these points, and an object of the present invention is to provide a semiconductor device and a method for manufacturing the semiconductor device that reduce the number of components and reduce the manufacturing cost.

  According to one aspect of the present invention, a semiconductor module having a semiconductor element, a front surface and a back surface facing the front surface, the lid on which the semiconductor module is mounted on the front surface, And a cooling device having a storage portion joined to the back surface of the lid with a brazing material. The storage portion has a housing shape having a bottom surface, has a refrigerant flow path between the lid and the bottom surface, has an inlet at one end of the flow path, and flows into the other end of the flow path. A housing part provided with an outlet, and a first fixing part provided around the inflow port and a second provided around the outflow port in order to fix the housing part to an external installation region. A fixing part. Further, the casing part, the first fixing part, and the second fixing part are a cast product integrally formed by a casting method including a material having a liquidus temperature higher than the liquidus temperature of the brazing material. is there.

  A method for manufacturing the semiconductor device is also provided.

  According to the disclosed technology, it is possible to reduce the manufacturing cost of the semiconductor device.

It is a figure for demonstrating the manufacturing process of the semiconductor device of embodiment. It is a side view of the semiconductor device of an embodiment. It is a perspective view of the radiation fin part of an embodiment. It is a perspective view of the upper lid of an embodiment. It is a perspective view (front surface side) of the lower storage part of an embodiment. It is a perspective view (back side) of the lower storage part of an embodiment. It is a perspective view (front surface side) of the housing | casing part in which the radiation fin part of embodiment was accommodated. It is a perspective view of the cooling device of an embodiment. It is principal part sectional drawing of the upper cover brazed to the lower storage part and lower storage part of embodiment. It is sectional drawing of the cooling device of embodiment. It is a perspective view (back side) of the lower storage part to which the piping part of an embodiment was joined. It is a figure for demonstrating the manufacturing process of the semiconductor device of a reference example. It is a perspective view of the semiconductor device of a reference example. It is a perspective view of the upper cover of a reference example. It is a perspective view (front surface side) of the housing | casing part of a reference example. It is a perspective view of the piping part of a reference example. It is a perspective view (front surface side) of the housing | casing part by which the radiation fin part of the reference example was accommodated, the piping part was connected, and the fixing | fixed part was set. It is a graph which shows the junction temperature of the semiconductor module with respect to the heat conductivity of embodiment.

Hereinafter, embodiments will be described with reference to the drawings.
First, a semiconductor device and manufacturing of the semiconductor device will be described with reference to FIGS.
FIG. 1 is a diagram for explaining a manufacturing process of the semiconductor device of the embodiment.

FIG. 2 is a side view of the semiconductor device according to the embodiment.
As shown in FIGS. 1 and 2, the semiconductor device 1 includes a semiconductor module 2 and a cooling device 3 on which the semiconductor module 2 is mounted via solder (not shown).

The semiconductor module 2 includes power semiconductor elements 21 a and 21 b and a laminated substrate 22.
The power semiconductor elements 21a and 21b are, for example, IGBTs (Insulated Gate Bipolar Transistors), MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), FWDs (Free Wheeling Diodes), and the like. The number of power semiconductor elements 21a and 21b is not limited to two, and a number according to need is provided.

The multilayer substrate 22 includes an insulating plate 22a, a circuit board 22b formed on the front surface of the insulating plate 22a, and a metal plate 22c formed on the back surface of the insulating plate 22a.
The insulating plate 22a is made of an electrically insulating material. Examples of such a material include aluminum oxide and silicon nitride.

The circuit board 22b is made of a metal such as copper having excellent conductivity and has a plurality of circuit patterns (not shown).
The metal plate 22c is disposed on the entire back surface of the insulating plate 22a and is made of aluminum, iron, silver, copper, an alloy containing these, or the like having high thermal conductivity.

  The semiconductor module 2 seals the case for housing the power semiconductor elements 21a and 21b and the laminated substrate 22, the wiring for connecting the power semiconductor elements 21a and 21b to the circuit pattern, the power semiconductor elements 21a and 21b, the circuit board 22b, and the wiring. A sealing material may be included. The semiconductor module 2 may be sealed by a transfer molding method.

  The cooling device 3 has the semiconductor module 2 mounted thereon, and has an upper lid 32 and a lower storage portion 33. The cooling device 3 may further include a radiation fin portion 31. In FIG. 2, illustration of each component of the cooling device 3 is omitted.

Hereinafter, each structure of the cooling device 3 and the cooling device 3 are demonstrated using FIGS. 3-6 (and FIG. 1).
FIG. 3 is a perspective view of the radiation fin portion of the embodiment.

FIG. 4 is a perspective view of the upper lid of the embodiment.
FIG. 5 is a perspective view (front surface side) of the lower storage portion of the embodiment.
FIG. 6 is a perspective view (back side) of the lower storage portion of the embodiment.

  As shown in FIG. 3, the heat dissipating fin portion 31 includes a plurality of fins in parallel. The radiating fin portion 31 is formed by extrusion or pressing. The heat radiating fin portion 31 is made of aluminum or the like excellent in thermal conductivity.

  As shown in FIG. 4, the upper lid 32 is a rectangular plate having a front surface 32f and a back surface 32b opposite to the front surface 32f. The upper lid 32 has screw holes 321a to 321d formed at four corners, respectively. The upper lid 32 is formed by pressing. The upper lid 32 is made of aluminum or the like excellent in thermal conductivity.

  The lower housing portion 33 is formed by casting (die casting) obtained by pouring a molten aluminum-based alloy into a mold and cooling it, and then removing it from the mold. In addition, the aluminum alloy which is a die-cast material has the characteristics that the thermal conductivity is 150 W / (mK) or more and the liquidus temperature is 600 ° C. or more. An aluminum alloy having a thermal conductivity of 150 W / (mK) or more and 200 W / (mK) or less and a liquidus temperature of 600 ° C. or more and 660 ° C. or less is preferable from the viewpoint of castability. Examples of such alloys include AC4D (aluminum-silicon-copper-magnesium alloy), DX17 (aluminum-7 silicon-magnesium-iron alloy), DX26 (aluminum-2 nickel-iron alloy) manufactured by Nippon Light Metal Co., Ltd. Can be mentioned.

  As shown in FIGS. 5 and 6, the lower storage portion 33 formed in this way is a housing-like box-shaped container having a bottom surface 331 b. The lower storage portion 33 includes a housing portion 331, first fixing portions 334a and 334b, and second fixing portions 334c and 334d.

  In the illustrated example, the housing portion 331 has a substantially rectangular parallelepiped shape. The housing portion 331 is provided with an inflow port 332a at one end and an outflow port 332b at the other end on the opposite side with the flow path 331p interposed therebetween. The inflow port 332a and the outflow port 332b may be provided on the bottom surface 331b of the housing portion 331, respectively. A channel 331p through which a refrigerant can flow is provided between the upper lid 32 and the bottom surface 331b of the housing portion 331. A refrigerant circulation system can be connected to the inflow port 332a and the outflow port 332b, and the refrigerant can circulate through the paths of the inflow port 332a, the flow path 331p, and the outflow port 332b.

  The first fixing parts 334a and 334b and the second fixing parts 334c and 334d may be fixed to an external installation area. The housing portion 331, the first fixing portions 334a and 334b, and the second fixing portions 334c and 334d are integrally formed.

  The inflow port 332a and the outflow port 332b are formed to face each other on the longitudinal center line (the chain line in FIG. 5) of the housing portion 331. A first thick portion 333a is formed around the inflow port 332a, and a second thick portion 333b is formed around the outflow port 332b. The first thick part 333 a and the second thick part 333 b are formed in a staircase (terrace) shape from the bottom surface 331 of the housing part 331 toward the upper lid 32. The first thick part 333a and the second thick part 333b are formed thicker than the bottom surface 331b of the housing part 331. The inflow port 332a and the outflow port 332b each open to the terrace.

  First fixing portions 334a and 334b are formed integrally with the housing portion 331 on both sides (in the short-side direction) of the inflow port 332a, and a joint between the housing portion 331 and the first fixing portions 334a and 334b is formed. The recesses 335a and 335b are formed. On both sides of the inflow port 332a, the side wall of the housing portion 331 is formed with an angle along the first fixing portions 334a and 334b (curves a1 and a2), and the height of the side wall is the first fixing portion. It is the same thickness as 334a and 334b.

  Second fixing portions 334c and 334d are also formed integrally with the housing portion 331 on both sides (in the short direction) of the outflow port 332b, and a joint between the housing portion 331 and the second fixing portions 334c and 334d is formed. The recesses 335c and 335d are formed. On both sides of the outlet 332b, the side wall of the housing portion 331 is formed with an angle along the second fixing portions 334a and 334b (curves a3 and a4), and the height of the side wall is the fixing portion 334c, It is the same thickness as 334d.

  The first fixing portions 334a and 334b include solid portions 334as and 334bs that are solid. The second fixing portions 334c and 334d include solid portions 334cs and 334ds that are solid. The solid portions 334as and 334bs and the solid portions 334cs and 334ds are thicker than the first thick portion 333a and the second thick portion 333b, and are integrally formed with the housing portion 331 by a forging method. The first fixing portions 334a and 334b and the second fixing portions 334c and 334d may have holes penetrating from the front surface to the back surface in addition to the solid portions 334as and 334bs and the solid portions 334cs and 334ds, respectively. . These through holes may be provided coaxially with the screw holes 321a to 321d of the upper lid 32, respectively.

  The solid portions 334as and 334bs of the first fixing portions 334a and 334b include a first side wall 334aw and a second side wall 334bw facing each other with the inflow port 332a interposed therebetween. The first side wall 334 aw and the second side wall 334 bw are formed from the first thick part 333 a toward the upper lid 32. The first side wall 334aw and the second side wall 334bw are not parallel, but have an angle as shown by the curves a1 and a2, and the distance between them decreases as the distance from the second fixing portions 334c and 334d increases.

  Similarly, the solid portions 334cs and 334ds of the second fixing portions 334c and 334d include a third side wall 334cw and a fourth side wall 334dw that are opposed to each other with the inflow port 332b interposed therebetween. The third side wall 334cw and the fourth side wall 334dw are formed from the second thick part 333b toward the upper lid 32. The third side wall 334cw and the fourth side wall 334dw are not parallel but have an angle as indicated by the curves a3 and a4, and the distance between them decreases as the distance from the first fixing portions 334a and 334b increases.

As shown in FIG. 6, the back surface 336 of the lower storage portion 33 is flat with a housing portion 331 and fixing portions 334 a to 334 d formed in a plane.
Further, the minimum thickness of the bottom surface 331b of the lower storage portion 33 is about 1 mm, and the thicknesses of the first thick portion 333a and the second thick portion 333b are about 4 mm. Furthermore, the height of the side walls (the first side wall 334 aw, the second side wall 334 bw, the third side wall 334 cw, and the fourth side wall 334 dw) that surrounds both sides of the inlet 332 a and the outlet 332 b of the lower storage portion 33 is about 10 mm. .

Next, the assembly structure of the cooling device 3 will be described with reference to FIGS. 7 to 9 (and FIG. 1).
FIG. 7 is a perspective view (front surface side) of a housing portion in which the heat dissipating fin portions of the embodiment are housed.

FIG. 8 is a perspective view of the cooling device according to the embodiment.
FIG. 9 is a cross-sectional view of the main part of the lower storage portion and the upper lid brazed to the lower storage portion of the embodiment.

  First, for example, a brazing material such as gold, silver, copper, or aluminum is applied to the housing portion 331 of the lower housing portion 33, and the radiating fin portion 31 is disposed in the housing portion 331 as shown in FIG. To do. As the brazing material, aluminum brazing containing aluminum and silicon as main components is preferably used. The aluminum brazing may contain additional components such as copper, magnesium and zinc.

  The inflow port 332a and the outflow port 332b are arranged on the bottom surface 331b of the housing portion 331 on one side and the other side of each fin with the heat radiating fin portion 31 arranged in this way interposed therebetween. (Dashed line in FIG. 7). For this reason, the refrigerant that has flowed into the housing portion 331 from the inflow port 332a flows between the fins of the radiating fin portion 31, and flows out from the outflow port 332b. In this way, in the housing portion 331, the refrigerant flow path 331 p including the heat radiation fin portion 31 is provided between the upper lid 32 and the bottom surface 331 b of the housing portion 331.

  Next, as shown in FIG. 8, the upper lid 32 having the back surface 32 b coated with a brazing material is disposed in the opening of the housing portion 331 with respect to the lower storage portion 33. As the upper lid 32, a clad material obtained by previously bonding a brazing material in layers may be used. At this time, the screw holes 321a to 321d of the upper lid 32 and the fixing portions 334a to 334d are aligned with each other.

  Then, brazing is performed by pressing the upper lid 32 toward the lower storage portion 33 at a brazing temperature of 575 ° C. or more and less than 600 ° C. As a result, the upper lid 32 is brazed to the upper end portion of the radiating fin portion 31, the edge of the casing portion 331, and the fixing portions 334 a to 334 d, and the lower end portion of the radiating fin portion 31 is connected to the casing portion 331. The bottom surface 331b is brazed.

  At this time, since the liquidus temperature of the lower housing part 33 is 600 ° C. or higher, which is higher than the liquidus temperature of the brazing material, the lower housing part 33 is not melted by brazing, and the radiating fin part 31 and the upper lid 32 and the lower storage part 33 can be brazed together reliably.

  In addition, the edge of the housing | casing part 331 of the lower accommodating part 33 has comprised the shape along the outer side, as FIG. 9 shows. For this reason, the upper lid 32 can be reliably brazed to the edge of the housing portion 331 of the lower storage portion 33.

The semiconductor device 1 is configured by installing the semiconductor module 2 on the upper lid 32 of the cooling device 3 via solder.
The cooling device 3 includes a pump that circulates the refrigerant into the inflow port 332a and circulates the refrigerant that flows out of the outflow port 332b, and a heat radiating device (radiator) that radiates the heat of the circulated refrigerant to the outside. May be.

  In the semiconductor device 1, heat generated as the power semiconductor elements 21 a and 21 b of the semiconductor module 2 operate is conducted to the cooling device 3 via the laminated substrate 22. In the cooling device 3, the heat conducted to the radiating fin portion 31 via the upper lid 32 is conducted to the refrigerant by the radiating fin portion 31, and is radiated to the outside by circulating the refrigerant.

A cross-sectional view of the cooling device 3 will be described with reference to FIG.
FIG. 10 is a cross-sectional view of the cooling device according to the embodiment.
10 is a cross-sectional view taken along one-dot chain line YY of the cooling device 3 of FIG.

  In the cooling device 3, the radiating fin portion 31 housed in the housing portion 331 of the lower housing portion 33 is brazed at its lower end portion to the bottom surface 331 b of the housing portion 331 and its upper end portion to the back surface 32 b of the upper lid 32. Has been.

  When the semiconductor module 2 disposed on the upper lid 32 of the cooling device 3 generates heat, the upper lid 32 generates thermal stress and warps. However, since the upper end and the lower end of the radiating fin portion 31 are brazed to the upper lid 32 and the bottom surface of the housing portion 331, warping of the upper lid 32 is suppressed. Thereby, it is prevented that the cooling device 3 is damaged, and a decrease in the reliability of the cooling device 3 can be suppressed.

Next, in the cooling device 3, the lower storage portion to which the piping portion is joined will be described with reference to FIG. 11.
FIG. 11 is a perspective view (back side) of the lower storage portion to which the piping portion of the embodiment is joined.

  The lower storage portion 33a is configured such that piping portions 337a and 337b are integrally provided from the back surface 336 side to the inflow port 332a and the outflow port 332b of the housing portion 331, and the other configuration is the lower storage portion. The configuration is the same as that of the unit 33.

  In such a lower storage part 33a, a mold in which a mold for the piping parts 337a and 337b is newly formed with respect to the mold used for forming the lower storage part 33 is used. A lower part in which the casing 331, the fixing parts 334a to 334d, and the pipe parts 337a and 337b are integrally formed by performing die casting on the mold like the case of the lower housing part 33. A storage portion 33a is formed.

Here, a cooling device as a reference example will be described with reference to FIGS.
FIG. 12 is a diagram for explaining a manufacturing process of the semiconductor device of the reference example.
FIG. 13 is a perspective view of a semiconductor device of a reference example.

  As shown in FIGS. 12 and 13, the semiconductor device of the reference example (not shown) has the same semiconductor module 2 as that of the embodiment, and cooling in which the semiconductor module 2 is mounted via solder not shown. Device 4.

  As described with reference to FIG. 2, the semiconductor module 2 includes the power semiconductor elements 21 a and 21 b and the multilayer substrate 22. For this reason, detailed description of the power semiconductor elements 21a and 21b and the laminated substrate 22 is omitted.

  The cooling device 4 is mounted with the semiconductor module 2, and includes a heat radiating fin portion 41, an upper lid 42, a housing portion 43, piping portions 44a and 44b, a flange (not shown), and a fixing portion 45a. ~ 45d.

Hereinafter, each structure of the cooling device 4 and the cooling device 4 will be described with reference to FIGS. 14 to 16 (and FIGS. 12 and 13).
In addition, since the radiation fin part 41 has comprised the same structure as the radiation fin part 31 demonstrated above, description is abbreviate | omitted.

FIG. 14 is a perspective view of the upper lid of the reference example.
FIG. 15 is a perspective view (front surface side) of the housing portion of the reference example.
FIG. 16 is a perspective view of a piping portion of a reference example.

  As shown in FIG. 14, the upper lid 42 has a rectangular shape, and screw holes 421a to 421d are formed at the four corners, respectively. The upper lid 42 is formed by pressing. The upper lid 42 is made of aluminum or the like having excellent thermal conductivity.

  As shown in FIG. 15, the casing 43 has, for example, an octagonal container shape when viewed from above, and a refrigerant inlet 431 a and a refrigerant outlet 431 b are formed on a pair of opposing side walls. Each is formed. The housing | casing part 43 is formed by press work. The housing | casing part 43 is comprised with the aluminum etc. which were excellent in thermal conductivity.

  As shown in FIG. 16, the pipe portions 44 a and 44 b have, for example, a cylindrical shape. As described later, the pipe portions 44 a and 44 b have an end portion joined to the inlet 431 a and the outlet 431 b of the housing portion 43. A flange (not shown) is formed. The pipe portions 44a and 44b are formed by bulging, in which a pipe-shaped material is set in a mold and then clamped, and both ends of the material are axially compressed while being filled with a high-pressure liquid to perform hollow molding. Alternatively, the pipe portions 44a and 44b can be formed by cutting. The piping parts 44a and 44b are made of aluminum or the like having excellent thermal conductivity.

  The fixing portions 45a to 45d have screw holes into which screws are fitted, as shown in FIG. 17 described later. The fixing portions 45a to 45d are formed by an extrusion process in which a constituent material is strongly pressed and extruded from a hole of a predetermined mold. Alternatively, the fixing portions 45a to 45d can be formed by cutting.

Next, assembly of the cooling device 4 will be described with reference to FIG. 17 (and FIGS. 12 and 13).
FIG. 17 is a perspective view (front surface side) of a housing part in which the heat dissipating fin part of the reference example is accommodated, the pipe part is connected, and the fixing part is set.

First, a wax is applied in the housing portion 43, and the radiating fin portions 41 are disposed as shown in FIG.
And piping part 44a, 44b is joined to the inflow port 431a and the outflow port 431b of the housing | casing part 43, respectively.

In addition, after joining the piping parts 44a and 44b to the housing | casing part 43 previously, you may arrange | position the radiation fin part 41 in the housing | casing part 43. FIG.
Thus, with respect to the housing | casing part 43 in which the radiation fin part 41 is arrange | positioned and piping part 44a, 44b was joined, the fixing | fixed part 45a-45d is set to a predetermined position.

  Wax is applied to the vicinity of the screw holes 421 a to 421 d of the upper lid 42 and locations where the casing portion 43 and the heat radiating fin portions 41 are joined, and the upper lid 42 is disposed in the opening of the casing portion 43. At this time, the screw holes 421a to 421d of the upper lid 42 and the fixing portions 45a to 45d are aligned.

  And the upper cover 42 is pressed to the housing | casing part 43 side under the temperature of 575 degreeC-600 degreeC. Accordingly, the upper lid 42 is brazed to the upper end of the radiating fin portion 41 and the edge of the housing portion 43, and the lower end of the radiating fin portion 41 is brazed to the bottom surface of the housing portion 43.

Thereby, the cooling device 4 shown in FIG. 13 is obtained.
In such a cooling device 4, the configuration other than the upper lid 42 and the heat radiating fin portion 41 is divided into a housing portion 43, piping portions 44 a and 44 b, and fixing portions 45 a to 45 d.

  On the other hand, the lower storage portion 33 (and the lower storage portion 33a) of the cooling device 3 is composed of the housing portion 331, the fixing portions 334a to 334d (and the piping portions 337a to 337d), and the number of components is increased. Is suppressed.

  Moreover, in the housing | casing part 43 of the cooling device 4, it is requested | required that the dimensional tolerance at the time of joining piping part 44a, 44b to the inflow port 431a and the outflow port 431b as much as possible should be made as small as possible. When this dimensional tolerance is large, it becomes difficult to ensure airtightness between the casing 43 and the pipes 44a and 44b. A seal material or the like for reducing the dimensional tolerance is newly required, and the number of components increases.

  On the other hand, the lower storage portion 33a of the cooling device 3 realizes high dimensional accuracy because the piping portions 337a and 337b are integrally joined to the inlet 332a and the outlet 332b of the casing 331 by casting. can do.

Next, the simulation result performed regarding the cooling performance of the cooling device 3 will be described with reference to FIG.
FIG. 18 is a graph showing the junction temperature of the semiconductor module with respect to the thermal conductivity of the embodiment.

18, the horizontal axis represents the thermal conductivity (W / (mK)), and the vertical axis represents the junction temperature (° C.) of the semiconductor module 2.
18 represents a simulation result of the junction temperature of the semiconductor module 2 when the die-cast material of the lower housing portion 33 of the cooling device 3 is changed in the semiconductor device 1.

  Point A (black circle) is a reference example, and represents a case where an aluminum alloy (ADC12) having a thermal conductivity of 96 W / (mK) and a liquidus temperature of 580 ° C. is used as a die-cast material. Point B (white circle) is an aluminum alloy (DX17 in the embodiment) having a thermal conductivity of 170 W / (mK) and a liquidus temperature of 610 ° C., and point C (white circle) has a thermal conductivity of 190 W / (mK). ), An aluminum alloy having a liquidus temperature of 655 ° C. (DX26 of the embodiment) is shown as a die-cast material.

Further, as a refrigerant used in the cooling device 3, an ethylene glycol-based diluted LLC (Long Life Coolant) of 60 ° C. is set, and the flow rate is set to 2 liters / minute.
According to this graph, it can be seen that the junction temperature exceeds 155 ° C. at point A of the reference example. On the other hand, at the points B and C, it can be seen that the junction temperature is lower by 100 ° C. or more than the point A, and the cooling is further performed. This is probably because the lower storage part 33 at the points B and C has a higher heat conductivity than the lower storage part 33 at the point A, so that the heat dissipation rate is higher than that at the point A.

  Furthermore, as described above, the liquidus temperature of the die-cast material in the lower storage portion 33 at the points B and C exceeds 600 ° C., and is higher than the brazing temperature (575 ° C. to 600 ° C.). For this reason, even if the heat radiating fin portion 31 and the upper lid 32 are brazed to the lower storage portion 33 integrally formed by die casting, the cooling device 3 can be obtained without melting the lower storage portion 33.

  On the other hand, the liquidus temperature of the die-cast material of the lower storage portion 33 at point A is less than 600 ° C., which is about the brazing temperature. For this reason, if the radiation fin part 31 and the upper cover 32 are brazed to the lower storage part 33 integrally formed by die casting, the lower storage part 33 may be melted, and the cooling device 3 can be obtained appropriately. There is a case that cannot be done.

  The semiconductor device 1 includes a semiconductor module 2 including power semiconductor elements 21a and 21b, a front surface and a back surface facing the front surface, and the upper cover on which the semiconductor module 2 is mounted on the front surface. 32 and a cooling device 3 having a lower housing portion 33 joined to the back surface of the upper lid 32 with a brazing material. The lower storage portion 33 has a casing shape having a bottom surface 331b. The lower storage portion 33 has a coolant channel 331p between the upper lid 32 and the bottom surface 331b. An inlet 332a is provided at one end of the channel 331p. A casing 331 provided with an outlet 332b at the other end, and first fixing parts 334a and 334b provided around the inlet 332a and an outlet for fixing the casing 331 to an external installation area 2nd fixing | fixed part 334c, 334d provided in the circumference | surroundings of 332b. Cast product in which casing portion 331, first fixing portions 334a and 334b, and second fixing portions 334c and 334d include a material having a liquidus temperature equal to or higher than the liquidus temperature of the brazing material is integrally formed by a casting method It is.

  In such a cooling device 3 for the semiconductor device 1, the housing portion 331 and the fixing portions 334 a to 334 d are integrally formed by a casting method using a material whose liquidus temperature is equal to or higher than the brazing temperature. And the upper cover 32 and the radiation fin part 31 are integrally molded by brazing. Furthermore, the thermal conductivity of the material is 150 W / (mK) or more.

  Such a cooling device 3 can reduce the number of components to reduce the manufacturing cost, and can suppress a decrease in heat dissipation. In the lower storage portion 33a, in addition to the housing portion 331 and the fixing portions 334a to 334d, pipe portions 337a and 337b are integrally formed by the same casting method at the inlet 332a and the outlet 332b of the housing portion 331. Has been. For this reason, it is possible to reduce the number of components to reduce the manufacturing cost, and to suppress a decrease in heat dissipation, and to realize high dimensional accuracy and position accuracy. Further, the lower storage portions 33 and 33a can be optimally formed with pipe shapes and arrangement positions of the pipe portions 337a and 337b, the inlet 332a and the outlet 332b according to the mold used in the casting process, and the degree of freedom in design can be increased. improves.

  In the lower storage portions 33 and 33 a, a first thick portion 333 a and a second thick portion 333 b are formed thicker than the bottom surface 331 b of the housing portion 331. Further, both sides of the inflow port 332a and the outflow port 332b are solid solid portions 334as, 334bs and solid portions 334cs, 334ds, a first side wall 334aw, a second side wall 334bw, a third side wall 334cw, and a fourth side wall 334dw. The first fixed portions 334a and 334b and the second fixed portions 334c and 334d are included. Since the storage portions 33 and 33a are formed by a casting method, the first thick portion 333a, the second thick portion 333b, the solid portions 334as and 334bs, and the solid portions 334cs and 334ds can be formed without increasing the number of steps. .

  With such a structure, the cooling device 3 is unlikely to buckle even when a large mechanical force is applied to the inlet 332a and the outlet 332b. Further, the heights of the first side wall 334aw, the second side wall 334bw, the third side wall 334cw, and the fourth side wall 334dw are the same thickness as the fixing portions 334a to 334d, and the side walls are shown by curves a1 to a4 in FIG. There may be an angle along. Thereby, even if pressure is applied to the inlet 332a and the outlet 332b of the cooling device 3, it is possible to prevent the lower storage portion 33 from buckling.

DESCRIPTION OF SYMBOLS 1 Semiconductor device 2 Semiconductor module 3 Cooling device 21a, 21b Power semiconductor element 22 Laminated substrate 22a Insulation plate 22b Circuit board 22c Metal plate 31 Radiation fin part 32 Upper cover 33, 33a Lower storage part 321a-321d Screw hole 331 Case part 331b Bottom face 331p flow path 332a inflow port 332b outflow port 333a first thick portion 333b second thick portion 334a, 334b first fixed portion 334as, 334bs, 334cs, 334ds solid portion 334aw first side wall 334bw second side wall 334c, 334d 2 fixed part 334cw 3rd side wall 334dw 4th side wall 335a-335d hollow 336 back surface 337a-337d Piping part

Claims (14)

A semiconductor module having a semiconductor element;
A front surface and a rear surface facing the front surface; the lid on which the semiconductor module is mounted on the front surface; and a storage portion joined to the rear surface of the lid with a brazing material. A cooling device;
Including
The storage section is
The casing has a bottom surface, and has a refrigerant flow path between the lid and the bottom surface, an inlet is provided at one end of the flow path, and an outlet is provided at the other end of the flow path. A housing part;
A first fixing part provided around the inflow port and a second fixing part provided around the outflow port in order to fix the housing part to an external installation area;
The casing part, the first fixing part, and the second fixing part include a material having a liquidus temperature equal to or higher than the liquidus temperature of the brazing material, and are a cast product integrally formed by a casting method.
Semiconductor device. The liquidus temperature of the material is 600 ° C. or higher,
The thermal conductivity of the material is 150 W / (mK) or more.
The semiconductor device according to claim 1. The material is an aluminum alloy;
The semiconductor device according to claim 2. The liquidus temperature of the brazing material is 575 ° C. or more and less than 600 ° C.,
The semiconductor device according to claim 1. The inflow port and the outflow port are respectively formed on the bottom surface of the housing portion.
The semiconductor device according to claim 1. The housing includes a step-like first thick part and a second thick part formed from the bottom surface toward the lid, and the first thick part is formed around the inflow port. 2 thick parts are provided around the outlet,
The first fixing part is solid and includes a solid part thicker than the first thick part; the second fixing part is solid and includes a solid part thicker than the second thick part;
The semiconductor device according to claim 5. The solid part of the first fixed part includes a first side wall and a second side wall that are formed facing the lid from the first thick part, with the inflow port interposed therebetween, The distance between the first side wall and the second side wall decreases as the distance from the second fixing portion increases.
The semiconductor device according to claim 6. The inflow port and the outflow port are respectively disposed opposite to each other on a center line passing through the center of the housing portion.
The semiconductor device according to claim 6. The fixing part is disposed on both sides of the inflow port at right angles to the center line;
The side wall of the housing part around the inflow port is formed along the fixed part,
The semiconductor device according to claim 8. The fixing portion is disposed on both sides of the outlet and perpendicular to the center line;
The side wall of the housing part around the outlet is formed along the fixed part.
The semiconductor device according to claim 8. As for the said accommodating part, the piping part is integrally formed by the said casting method in the said inflow port and the said outflow port, respectively.
6. The semiconductor device according to claim 1 or 5. A radiating fin portion having a plurality of fins parallel to a direction in which the refrigerant flowing in from the inflow port flows between the inflow port and the outflow port is accommodated in the housing unit. ing,
The semiconductor device according to claim 8. The lower end portion of the radiating fin portion is brazed to the bottom surface of the housing portion, and the upper end portion of the radiating fin portion is brazed to the back surface of the lid,
The semiconductor device according to claim 12. Preparing a semiconductor module having a semiconductor element;
Preparing a lid;
A casing portion having a casing shape, in which a refrigerant inlet and a refrigerant outlet are formed, and a fixing portion that fixes the casing portion to an external installation area are integrally formed by a casting method. Preparing a storage section,
Forming the cooling device integrally by covering the casing with the lid and joining with a brazing material;
Mounting the semiconductor module on the cooling device, and
A method for manufacturing a semiconductor device, wherein the housing part and the fixing part include a material having a liquidus temperature equal to or higher than a liquidus temperature of the brazing material.

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