JP2023032484A - Power semiconductor unit, manufacturing method of power semiconductor unit - Google Patents

Abstract

To provide a power semiconductor unit including a cooler capable of balancing the cooling efficiency and mounting flexibility of the mounted power semiconductor module.SOLUTION: The power semiconductor unit includes: a power semiconductor element; a first insulating substrate bonded to one side of the power semiconductor element; a wiring metal component bonded to the other side of the power semiconductor element; a second insulating substrate bonded to the side of the wiring metal component opposite to the side to which the power semiconductor element is bonded; and a heat sink for cooling the heat from the power semiconductor element. The connection between the power semiconductor element and the first insulating circuit board, the connection between the power semiconductor element and the wiring metal component, and the connection between the wiring metal component and the second insulating substrate are a sintered metal joint.SELECTED DRAWING: Figure 1

Description

The present invention relates to a structure of a power semiconductor unit and a method of manufacturing the same, and more particularly to a technique effectively applied to a power semiconductor unit provided with a cooler.

In recent years, along with growing awareness of the environment, eco-friendly vehicles such as hybrid electric vehicles (HV) and electric vehicles (EV) are becoming popular. Due to the further spread of next-generation HVs and EVs, the development of smaller, lower-cost, and more efficient electric power systems is underway. Among these, miniaturization, lower cost, and higher efficiency of power semiconductor units are important. This is one of the issues.

BACKGROUND ART For example, Patent Document 1 discloses a technology related to an in-vehicle power semiconductor unit. Patent Document 1 discloses a configuration of a power semiconductor module in which insulating substrates attached to both sides of a power semiconductor element and cooling means such as a heat sink are joined by brazing such as soldering or brazing.

With the configuration of Patent Document 1, the thermal resistance between the power semiconductor element and the cooling means is greatly reduced, and high cooling performance can be obtained.

JP 2008-124430 A

In Patent Document 1, the power semiconductor elements 1 and 2 are joined to the insulating substrates 9 and 18 by soldering or the like, and the insulating substrates 9 and 18 are connected to the heat sinks 13 and 23 provided with heat sink fins. They are joined by brazing (soldering or brazing).

As a result, the solder at the joints between the power semiconductor elements 1 and 2 and the insulating substrates 9 and 18 melts again due to the heat in the brazing process when the heat sinks 13 and 23 are joined to the insulating substrates 9 and 18. , there is a concern that the reliability and thermal conductivity (cooling efficiency) of the joints between the power semiconductor elements 1 and 2 and the insulating substrates 9 and 18 will be lowered.

Patent Document 1 discloses that a high-temperature bonding material in which copper particles and tin particles are mixed, for example, is used as a bonding material such as solder for bonding the power semiconductor elements 1 and 2 to the insulating substrates 9 and 18. The bonding material such as solder for bonding the heat sinks 13 and 23 to the insulating substrates 9 and 18 has a lower melting point than the bonding material such as solder for bonding the power semiconductor elements 1 and 2 to the insulating substrates 9 and 18. For example, the use of Sn-3Ag-0.5Cu lead-free solder is disclosed.

However, both CuSn solder, which is a high-temperature bonding material, and Sn-3Ag-0.5Cu lead-free solder exemplified in Patent Document 1 are solders, and even CuSn solder, which is a high-temperature bonding material, contains Sn. Since the melting point is about 350°C at the highest, there is a limit to changing the melting point greatly, and the heat generated when Sn-3Ag-0.5Cu lead-free soldering may deteriorate the quality of CuSn solder. have a nature.

Further, when an electric system for vehicle is to be constructed using the power semiconductor module of Patent Document 1, a mounting structure considering remelting of the solder at the joints between the power semiconductor elements 1 and 2 and the insulating substrates 9 and 18 is required. design is required, and there are certain restrictions in mounting the power semiconductor module.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a power semiconductor unit equipped with a cooler, and a method of manufacturing the power semiconductor unit, which is capable of achieving both cooling efficiency and mounting freedom of the mounted power semiconductor module.

In order to solve the above problems, the present invention provides a power semiconductor element, a first insulating substrate bonded to one surface of the power semiconductor element, and a wiring metal bonded to the other surface of the power semiconductor element. a component, a second insulating substrate bonded to the surface of the wiring metal component opposite to the surface to which the power semiconductor element is bonded, and a heat sink for cooling heat from the power semiconductor element, The bonding between the power semiconductor element and the first insulating substrate, the bonding between the power semiconductor element and the wiring metal component, and the bonding between the wiring metal component and the second insulating substrate are sintered metal bonding. characterized by

Further, the present invention includes: (a) a step of bonding a power semiconductor element onto a first insulating substrate by sintered metal bonding; and (b) bonding a wiring metal component onto the power semiconductor element by sintered metal bonding. (c) bonding a second insulating substrate onto the wiring metal component by sintered metal bonding; (d) the first insulating substrate, the power semiconductor element, the wiring metal component and the second (e) after step (d), bonding the first insulating substrate to the heat sink by solder bonding or sintered metal bonding; A method of manufacturing a power semiconductor unit including:

Further, the present invention cools a first power semiconductor module, a second power semiconductor module superimposed on the first power semiconductor module, and the first power semiconductor module and the second power semiconductor module. a heat sink, wherein the heat sink has at least one liquid-cooled heat sink, and the first power semiconductor module has two main surfaces only one of which is thermally coupled to the liquid-cooled heat sink. The second power semiconductor module is characterized in that only one of two main surfaces of the second power semiconductor module is thermally connected to the liquid-cooled heat sink.

ADVANTAGE OF THE INVENTION According to this invention, in the power semiconductor unit provided with the cooler, the power semiconductor unit which can balance the cooling efficiency of a mounted power semiconductor module, and mounting flexibility, and its manufacturing method can be implement|achieved.

Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

It is a figure which shows the cross-section of the power semiconductor unit which concerns on Example 1 of this invention. It is a figure which shows the structure of the power semiconductor unit which concerns on Example 2 of this invention. FIG. 2B is a diagram showing a method of incorporating the power semiconductor unit of FIG. 2A into a cooling jacket; It is a figure which shows the modification of FIG. 2A and FIG. 2B. It is a figure which shows the mounting example of the power semiconductor unit which concerns on Example 2 of this invention. It is a figure which shows the structure of the power semiconductor unit which concerns on Example 3 of this invention. FIG. 5B is a diagram showing a cross section taken along line A-A' of FIG. 5A; It is a figure which shows the structure of the power semiconductor unit which concerns on Example 4 of this invention. FIG. 6B is a diagram showing a B-B′ cross section of FIG. 6A. It is a figure which shows the structure of the power semiconductor unit which concerns on Example 5 of this invention. FIG. 7B is a diagram showing a C-C′ cross section of FIG. 7A.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in each drawing, the same configurations are denoted by the same reference numerals, and detailed descriptions of overlapping portions are omitted.

A power semiconductor unit according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a cross-sectional structure of a power semiconductor unit 1 of this embodiment.

In this specification, semiconductor chips on which power semiconductor elements such as power MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), insulated gate bipolar transistors (IGBTs), and diodes are formed are referred to as " A power semiconductor element mounted on an insulating substrate and sealed with resin is called a "power semiconductor module", and a power semiconductor module equipped with a cooler such as a heat sink is called a "power semiconductor unit". call.

As shown in FIG. 1, the power semiconductor unit 1 of this embodiment includes, as main components, a power semiconductor element 3 which is a semiconductor chip on which a power semiconductor element such as an IGBT is formed, and a The bonded insulating substrate 2, the wiring metal component 4 such as a spacer or lead frame bonded to the upper surface of the power semiconductor element 3, and the surface of the wiring metal component 4 opposite to the surface to which the power semiconductor element 3 is bonded. It has a bonded insulating substrate 5 and heat sinks 6 and 7 for cooling the heat from the power semiconductor element 3 .

The insulating substrate 2 is, for example, a DBC substrate (Direct Bonded Copper) in which copper plates 9 and 10 are bonded to both sides of a ceramic substrate 8 . Similarly, the insulating substrate 5 is a DBC substrate or the like in which copper plates 12 and 13 are bonded to both sides of a ceramic substrate 11 .

The heat sinks 6 and 7 are provided with cooling fins, and cool the heat from the power semiconductor element 3 by heat exchange with the coolant 19 . In the case of an air-cooled heat sink, the refrigerant 19 is gas such as air, and in the case of a liquid-cooled heat sink, the refrigerant 19 is cooling water, LLC (Long Life Coolant), or the like.

A sintered metal 14 is interposed between the power semiconductor element 3 and the insulating substrate 2 , and the power semiconductor element 3 and the insulating substrate 2 are sintered metal bonded by the sintered metal 14 .

A sintered metal 15 is interposed between the power semiconductor element 3 and the wiring metal component 4 , and the power semiconductor element 3 and the wiring metal component 4 are sintered metal bonded by the sintered metal 15 . there is

A sintered metal 16 is interposed between the metal wiring component 4 and the insulating substrate 5 .

Sintered silver, sintered copper, or the like is used for the sintered metals 14, 15, and 16. FIG. The melting point of sintered metals such as sintered silver and sintered copper is as high as 900° C. or higher. The sintering temperature of the sintered metal joints forming the sintered metals 14, 15, 16 is about 200° C. to 350° C., and once the sintered metal joints are joined, the melting point is much higher than the sintering temperature. There is

The heat sink 6 is bonded to the surface of the insulating substrate 2 opposite to the surface to which the power semiconductor element 3 is bonded. is interposed therebetween, and the insulating substrate 2 and the heat sink 6 are metal-bonded by solder or sintered metal 17 . In this way, instead of the so-called indirect cooling that thermally connects via heat-dissipating grease or heat-dissipating sheet, the so-called direct-cooling structure that thermally connects with a metal joint reduces the thermal resistance of the connection. can. Further, the melting point of solder is about 200.degree. C. to 350.degree. A sintering temperature of about 200° C. to 350° C. can also be applied for sintering metal bonding forming the sintered metal 17 . Therefore, the step of joining with solder or the sintered metal 17 is performed at a temperature much lower than the melting point of the sintered metals 14, 15, 16 formed in the previous step, so that the sintered metals 14, 15 , 16 does not cause problems such as remelting and deterioration of quality.

The heat sink 7 is bonded to the surface of the insulating substrate 5 opposite to the surface to which the metal wiring component 4 is bonded. A metal 18 is interposed, and the insulating substrate 5 and the heat sink 7 are metal-bonded by solder or sintered metal 18 .

Only main steps of the method for manufacturing the power semiconductor unit 1 will be described with reference to FIG.

First, the power semiconductor element 3 is bonded onto the insulating substrate 2 by sintered metal bonding. At this time, a sintered metal 14 as a bonding layer is formed between the insulating substrate 2 and the power semiconductor element 3 .

Next, the wiring metal component 4 is joined onto the power semiconductor element 3 by sintered metal joining. At this time, a sintered metal 15 as a bonding layer is formed between the power semiconductor element 3 and the wiring metal component 4 .

Subsequently, the insulating substrate 5 is bonded onto the wiring metal component 4 by sintered metal bonding. At this time, a sintered metal 16 as a bonding layer is formed between the wiring metal component 4 and the insulating substrate 5 .

Note that the order of bonding is not limited to the order described above. Also, by using an alignment jig for fixing the position of each component, it is possible to form two or all of the joints of the sintered metal 14, the sintered metal 15, and the sintered metal 16 together. .

Next, the insulating substrate 2, the power semiconductor element 3, the wiring metal component 4, and the insulating substrate 5 are sealed with a sealing resin (not shown). In FIG. 1, the illustration of the sealing resin is omitted in order to make the structure easy to understand.

After resin sealing, the insulating substrate 2 and the heat sink 6, and the insulating substrate 5 and the heat sink 7 are respectively joined by soldering or sintered metal joining.

The power semiconductor unit 1 of the present embodiment is configured as described above. Since the sintered metals 14, 15, 16 each having a melting point of 900° C. or higher are used for bonding with the substrate 5, the insulating substrate 2 and the heat sink 6, and the insulating substrate 5 and the heat sink 7 are bonded to each other at a melting point or sintering temperature. There is no need to consider remelting of the sintered metals 14, 15, 16 inside the power semiconductor module and deterioration of their quality when joining with solder or sintered metals 17, 18 at about 200.degree. C. to 350.degree.

As a result, the degree of freedom in attaching the heat sinks 6 and 7 to the power semiconductor module is improved, and the reliability of bonding inside the power semiconductor module and the reliability of bonding between the power semiconductor module and the heat sink can be ensured. Moreover, since the thermal resistance of the connecting portions between the heat sinks 6 and 7 and the power semiconductor module can be reduced, the cooling efficiency of the power semiconductor unit as a whole can also be improved.

A power semiconductor unit according to a second embodiment of the present invention will be described with reference to FIGS. 2A to 4. FIG. FIG. 2A is a diagram showing the configuration of the power semiconductor unit 1 of this embodiment. FIG. 2B is a diagram showing a method of incorporating the power semiconductor unit 1 of FIG. 2A into the cooling jacket 21. As shown in FIG. FIG. 3 is a diagram showing a modification of FIGS. 2A and 2B. FIG. 4 is a diagram showing a mounting example of the power semiconductor unit 1 of this embodiment.

As described in Embodiment 1, the power semiconductor unit 1 has the heat sinks 6 and 7 respectively joined to both surfaces of the power semiconductor module 20 by metal joint such as solder joint or sintered metal joint, as shown in FIG. 2A. It consists of

The power semiconductor unit 1 configured as shown in FIG. 2A is incorporated in, for example, a cooling jacket 21 having a plurality of openings 23 as shown in FIG. Cooled.

When the power semiconductor unit 1 is incorporated into the cooling jacket 21, the power semiconductor unit 1 is joined in the opening 23 of the cooling jacket 21 by solder joint or sintered metal joint.

Also, as in the modification shown in FIG. 3, the power semiconductor module 20 with the heat sinks 6 and 7 not joined is directly joined to the cooling jacket 24 with built-in cooling fins by solder joint or sintered metal joint. It is also possible to construct a power semiconductor unit. In this case, the cooling jacket 24 becomes a liquid-cooled heat sink. In order to improve the cooling efficiency, pin fins (not shown) or the like are installed in the flow path of the cooling jacket 24 .

Further, since the power semiconductor unit 1 configured as shown in FIG. 2A has improved cooling efficiency and mounting freedom, it is required to be mounted together with the capacitor 25 and the like as shown in FIG. It can be used as a power semiconductor unit for electric vehicles (EVs).

A configuration example of the power semiconductor unit in FIG. 4 will be described later in Example 4 (FIGS. 6A and 6B).

A power semiconductor unit according to Example 3 of the present invention will be described with reference to FIGS. 5A and 5B. FIG. 5A is a diagram showing the configuration of the power semiconductor unit of this embodiment. FIG. 5B is a diagram showing a cross section along A-A' in FIG. 5A.

In the power semiconductor unit of this embodiment, as shown in FIGS. 5A and 5B, the heat sink is composed of two aluminum fixing bars 26 and a cooling jacket 24 arranged between the two aluminum fixing bars 26. . The cooling jacket 24 also functions as a liquid-cooled heat sink. The aluminum fixing bar 26 also functions as an air-cooled heat sink.

A first power semiconductor module group in which a plurality of power semiconductor modules 20 are arranged in parallel is provided between the lower aluminum fixing bar 26 and the cooling jacket 24 .

A second power semiconductor module group in which a plurality of power semiconductor modules 20 are arranged in parallel is provided between the upper aluminum fixing bar 26 and the cooling jacket 24 .

For joining the lower aluminum fixing bar 26 and the power semiconductor module 20, joining the cooling jacket 24 and the power semiconductor module 20, and joining the upper aluminum fixing bar 26 and the power semiconductor module 20, soldering or Sintered metal joints are used.

The power semiconductor module 20 uses two pairs of terminals arranged mirror-symmetrically. Each of the power semiconductor module 20 in the upper layer and the power semiconductor module 20 in the lower layer has a main terminal through which a main current flows and a control terminal including at least a gate terminal. are bent and extended in the opposite direction to the control terminals of the power semiconductor module 20 in the lower layer.

In the power semiconductor unit of this embodiment, as described above, the heat sink has at least one liquid-cooled heat sink (cooling jacket 24), and the power semiconductor module 20 in the upper layer has one of two main surfaces. is thermally connected to the cooling jacket 24 , and the lower power semiconductor module 20 is thermally connected to the cooling jacket 24 only on one of the two main surfaces. As a result, the number of liquid-cooled heat sinks can be reduced.

One main surface of the upper power semiconductor module 20 is bonded to the cooling jacket 24 via a metal bonding material such as solder bonding or sintered metal bonding, and one main surface of the lower power semiconductor module 20 is It is joined to the cooling jacket 24 via a metal joining material such as solder joint or sintered metal joint. In this way, instead of the so-called indirect cooling that thermally connects via heat-dissipating grease or heat-dissipating sheet, the so-called direct-cooling structure that thermally connects with metal bonding material reduces the thermal resistance of the connection part. can.

Although the thermal resistance of the connecting portion is higher than that of the metal bonding material, it is also possible to use heat dissipating grease or a heat dissipating sheet in place of the metal bonding material such as solder bonding or sintered metal bonding.

By configuring the power semiconductor unit as in the present embodiment (FIGS. 5A and 5B), it is possible to achieve a configuration with good cost performance while emphasizing small size and light weight.

A power semiconductor unit according to a fourth embodiment of the present invention will be described with reference to FIGS. 6A and 6B. FIG. 6A is a diagram showing the configuration of the power semiconductor unit of this embodiment. FIG. 6B is a diagram showing a B-B' section of FIG. 6A.

In the power semiconductor unit of this embodiment, as shown in FIGS. 6A and 6B, a heat sink is composed of two cooling jackets 24 arranged vertically.

A plurality of power semiconductor modules 20 are stacked in two stages between two cooling jackets 24, and the power semiconductor modules 20 in the upper layer and the power semiconductor modules 20 in the lower layer are soldered or sintered metal bonded to each other. are spliced.

The lower cooling jacket 24 is bonded to the surface of the insulating substrate 2 of the lower power semiconductor module 20 opposite to the surface to which the power semiconductor elements 3 are bonded. The insulating substrate 5 of the power semiconductor module 20 is bonded to the surface opposite to the surface to which the metal wiring component 4 is bonded.

Soldering or sintering is used to join the insulating substrate 2 of the lower power semiconductor module 20 and the lower cooling jacket 24 and to join the insulating substrate 5 of the upper power semiconductor module 20 and the upper cooling jacket 24 . A metal joint is used.

Between the cooling jacket 24 on the upper side and the cooling jacket 24 on the lower side, a plurality of power semiconductor modules 20 are arranged in parallel and arranged in a vertically overlapping manner.

In the power semiconductor unit of this embodiment, as described above, the heat sink has two cooling jackets 24 arranged vertically, and one main surface of the upper power semiconductor module 20 has an upper cooling jacket 24 . Jacket 24 is thermally connected, lower cooling jacket 24 is thermally connected to one main surface of power semiconductor module 20 in the lower layer, and the other main surface of power semiconductor module 20 in the upper layer and the other main surface of power semiconductor module 20 in the lower layer The other main surface of power semiconductor module 20 is thermally connected.

Although the thermal resistance of the connecting portion is higher than that of the metal bonding material, it is also possible to use heat dissipating grease or a heat dissipating sheet in place of the metal bonding material such as solder bonding or sintered metal bonding.

By configuring the power semiconductor unit as in the present embodiment (FIGS. 6A and 6B), it is possible to achieve a configuration with good cost performance while emphasizing small size and light weight.

A power semiconductor unit according to Example 5 of the present invention will be described with reference to FIGS. 7A and 7B. FIG. 7A is a diagram showing the configuration of the power semiconductor unit of this embodiment. FIG. 7B is a view showing a C-C' section of FIG. 7A.

In the power semiconductor unit of this embodiment, as shown in FIGS. 7A and 7B, the heat sink is composed of three cooling jackets 24 arranged in three upper and lower layers.

A plurality of power semiconductor modules 20 are stacked in two stages between three cooling jackets 24, and the power semiconductor module 20 in the upper layer is between the cooling jacket 24 in the uppermost stage and the cooling jacket 24 in the middle stage. Joined by solder joints or sintered metal joints.

The lower power semiconductor module 20 is joined between the lowermost cooling jacket 24 and the middle cooling jacket 24 by solder joint or sintered metal joint.

Although the thermal resistance of the connecting portion is higher than that of the metal bonding material, it is also possible to use heat dissipating grease or a heat dissipating sheet in place of the metal bonding material such as solder bonding or sintered metal bonding.

By configuring the power semiconductor unit as in this embodiment (FIGS. 7A and 7B), both sides of all the power semiconductor modules 20 are cooled by the liquid cooling type cooling jacket 24, so that the maximum This is advantageous when you want to give priority to output.

In addition, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. In addition, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

DESCRIPTION OF SYMBOLS 1... Power semiconductor unit 2, 5... Insulating substrate 3... Power semiconductor element 4... Wiring metal part 6, 7... Heat sink 8, 11... Ceramic substrate 9, 10, 12, 13... Copper plate 14, 15, 16... Sintered metal REFERENCE SIGNS LIST 17, 18 Solder or sintered metal 19 Refrigerant 20 Power semiconductor module 21, 24 Cooling jacket 22 Water channel 23 Opening 25 Capacitor 26 Aluminum fixing bar

Claims (16)

a power semiconductor element;
a first insulating substrate bonded to one surface of the power semiconductor element;
a wiring metal component joined to the other surface of the power semiconductor element;
a second insulating substrate bonded to the surface of the wiring metal component opposite to the surface to which the power semiconductor element is bonded;
a heat sink that cools heat from the power semiconductor element,
The bonding between the power semiconductor element and the first insulating substrate, the bonding between the power semiconductor element and the wiring metal component, and the bonding between the wiring metal component and the second insulating substrate are sintered metal bonding. A power semiconductor unit characterized by: In the power semiconductor unit according to claim 1,
The power semiconductor unit, wherein the sintered metal joint is sintered silver joint or sintered copper joint. In the power semiconductor unit according to claim 1,
the heat sink is bonded to the surface of the first insulating substrate opposite to the surface to which the power semiconductor element is bonded;
A power semiconductor unit, wherein the bonding between the first insulating substrate and the heat sink is solder bonding or sintered metal bonding. In the power semiconductor unit according to claim 1,
The power semiconductor unit, wherein the heat sink cools the heat from the power semiconductor element by heat exchange with gas or liquid. In the power semiconductor unit according to claim 1,
A power semiconductor unit, comprising: a power semiconductor module in which the power semiconductor element, the first insulating substrate, the wiring metal part, and the second insulating substrate are sealed with the same sealing resin. . In the power semiconductor unit according to claim 5,
a first heat sink bonded to a surface of the first insulating substrate opposite to a surface to which the power semiconductor element is bonded;
a second heat sink bonded to the surface of the second insulating substrate opposite to the surface to which the wiring metal component is bonded;
The bonding between the first insulating substrate and the heat sink and the bonding between the second insulating substrate and the second heat sink are solder bonding or sintered metal bonding,
A power semiconductor unit, wherein a plurality of said power semiconductor modules are arranged in parallel between said first heat sink and said second heat sink. In the power semiconductor unit according to claim 6,
The plurality of power semiconductor modules are stacked in two stages between the first heat sink and the second heat sink,
A power semiconductor unit, wherein the power semiconductor module in the upper layer and the power semiconductor module in the lower layer are joined by solder joint or sintered metal joint. In the power semiconductor unit according to claim 5,
the heat sink has a first heat sink, a second heat sink, and a third heat sink;
a first power semiconductor module group in which a plurality of the power semiconductor modules are arranged in parallel between the first heat sink and the second heat sink;
a second power semiconductor module group in which a plurality of the power semiconductor modules are arranged in parallel between the second heat sink and the third heat sink;
The bonding between the first heat sink and the power semiconductor module, the bonding between the second heat sink and the power semiconductor module, and the bonding between the third heat sink and the power semiconductor module are solder bonding or sintered metal bonding. A power semiconductor unit characterized by: In the power semiconductor unit according to claim 8,
the second heat sink is positioned between the first heat sink and the third heat sink;
The second heat sink is a liquid-cooled heat sink,
The power semiconductor unit, wherein the first heat sink and the third heat sink are air-cooled heat sinks. A method of manufacturing a power semiconductor unit comprising the steps of;
(a) bonding a power semiconductor device onto a first insulating substrate by sintered metal bonding;
(b) bonding a wiring metal component onto the power semiconductor element by sintered metal bonding;
(c) bonding a second insulating substrate onto the wiring metal component by sintered metal bonding;
(d) sealing the first insulating substrate, the power semiconductor element, the wiring metal component, and the second insulating substrate with a sealing resin;
(e) bonding the first insulating substrate to a heat sink by solder bonding or sintered metal bonding after step (d); a first power semiconductor module;
a second power semiconductor module superimposed on the first power semiconductor module;
a heat sink that cools the first power semiconductor module and the second power semiconductor module;
the heat sink comprises at least one liquid-cooled heat sink;
The first power semiconductor module is thermally connected to the liquid-cooled heat sink only on one of two main surfaces,
A power semiconductor unit, wherein only one of two main surfaces of the second power semiconductor module is thermally connected to the liquid-cooled heat sink. In the power semiconductor unit according to claim 11,
The first power semiconductor module has the one main surface bonded to the liquid-cooled heat sink via a metal bonding material,
A power semiconductor unit, wherein the one main surface of the second power semiconductor module is bonded to the liquid-cooled heat sink via a metal bonding material. In the power semiconductor unit according to claim 11,
The first power semiconductor module has the one main surface thermally connected to the liquid-cooled heat sink via heat-dissipating grease or a heat-dissipating sheet,
A power semiconductor unit, wherein the one main surface of the second power semiconductor module is thermally connected to the liquid-cooled heat sink via heat-dissipating grease or a heat-dissipating sheet. In the power semiconductor unit according to claim 11,
The heat sink has a first non-liquid cooled heat sink and a second non-liquid cooled heat sink,
the one main surface of the first power semiconductor module and the one main surface of the second power semiconductor module are thermally connected to a common liquid-cooled heat sink;
The first heat sink is thermally connected to the other main surface of the first power semiconductor module,
A power semiconductor unit, wherein the second heat sink is thermally connected to the other main surface of the second power semiconductor module. In the power semiconductor unit according to claim 11,
The heat sink has a first liquid-cooled heat sink and a second liquid-cooled heat sink,
The first liquid-cooled heat sink is thermally connected to the one main surface of the first power semiconductor module,
The second liquid-cooled heat sink is thermally connected to the one main surface of the second power semiconductor module,
A power semiconductor unit, wherein the other main surface of the first power semiconductor module and the other main surface of the second power semiconductor module are thermally connected. In the power semiconductor unit according to claim 11,
each of the first power semiconductor module and the second power semiconductor module has a main terminal through which a main current flows and a control terminal including at least a gate terminal;
A power semiconductor unit, wherein the control terminals of the first power semiconductor module are bent and extend in a direction opposite to the control terminals of the second power semiconductor module.

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