JP2003338592A - Semiconductor module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure the reliability of a power semiconductor module over a long period of time by removing heat stress between respective members constituting a heat conduction route in the power semiconductor module. <P>SOLUTION: A power semiconductor module having IGBT elements 9 in its inside is provided with both of power conductivity and heat conductivity by bringing faces of electrodes 2, 4 and 5 composed of metal materials having high power conductivities and high heat conductivities directly into contact with power inputs and power outputs of the IGBT elements 9 without fusing members to be power and heat conduction routes in the power semiconductor module by a conductive fusing/joining member such as solder. The members to be the power and heat conduction routes in the power semiconductor module are formed as laminated structure, and an elastic member 13 for pressurizing the laminated members in a mutually press-contact state in the laminated direction is arranged in the power semiconductor module. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a semiconductor module used in a power converter and the like, and more particularly to a power semiconductor module.

[0002]

2. Description of the Related Art FIG. 22 is a sectional view showing a conventional power semiconductor module.
General-purpose IGBT (Insulated) equipped with a cooling device
(Gate Bipolar Transistor)
It is a module. In the figure, 61 is an IGBT module, 62 is a heat-radiating metal base plate made of aluminum, copper, or the like, 63 is an insulating substrate made of alumina, aluminum nitride, or the like having metal foils made of copper or the like bonded to both surfaces, and 64 is an IGBT.
T element, 65 is a collector electrode of the IGBT element 64, 66
Is an emitter electrode of the IGBT element 64.

Further, 67 is a collector bus bar of the main circuit wiring, 68 is an emitter bus bar of the main circuit wiring, 69 is a relay substrate, and 70 is an emitter electrode 66 of the IGBT element 64.
And aluminum wire connecting the bus bar 68 for work mitter, 7
1 is solder, 72 is a silicon gel for sealing the inside of the IGBT module 61, 73 is a cooling device such as a heat sink,
74 is a compound such as grease.

As shown in the figure, the collector electrode 65 of the IGBT element 64 is bonded onto the insulating substrate 63 via the solder 71, and the insulating substrate 63 is soldered onto the heat radiating metal base plate 62. The IGBT module 61 is connected and pressure-contacted to the cooling device 73 via the compound 74. I during operation of the IGBT module
The heat generated from the GBT element 64 is conducted to the cooling device 73 via the insulating substrate 63 and the heat-dissipating metal base plate 62, whereby the IGBT element 64 and the like are cooled.

Another structure of the power semiconductor module is GTO (Gate Turn-0ff Th).
A buffer electrode made of molybdenum, tungsten, etc., and a main electrode made of copper, etc. are provided on both sides of a power semiconductor element such as a yristor), and a cooling device such as a heat sink is attached to both sides of the power semiconductor module. There is a pressure contact stack type module in which the connection part is connected by pressure from the outside.

In the internal structure of these power semiconductor modules, since the linear expansion coefficients of the respective members used are different from each other, thermal deformation occurs due to temperature change during operation, which causes thermal stress. In addition, the amount of heat generated by the semiconductor element increases as the capacity increases, and the number of thermal cycles also increases, which poses a problem regarding long-term reliability.

For example, in the IGBT module 61, the linear expansion coefficient of the insulating substrate 63 is about 4 × 10 ^-6 / K when it is made of aluminum nitride, whereas the linear expansion coefficient of the heat radiating metal base plate 62 is Approximately 16 × 10 ^-6 / when composed of copper
In the case of K and aluminum, the difference is about 23 × 10 ⁻⁶ / K, which is very large. Therefore, due to temperature change during operation, thermal stress is applied to the joint between the insulating substrate 63 and the heat radiating metal base plate 62. When a hard material such as the conventional solder 71 is used, cracks are likely to occur, which causes a problem in long-term reliability. Further, a compound 74 having a low thermal conductivity is provided between the IGBT module 61 and the cooling device 73.
Since the structure is connected and pressure contacted with, there was a problem that the thermal resistance was high and the cooling performance was low.

In the pressure contact stack type module, the difference in linear expansion coefficient between the power semiconductor element and the main electrode is large.
A material having a linear expansion coefficient intermediate between the power semiconductor element and the main electrode material is inserted as a buffer electrode between the power semiconductor element and the main electrode to relax thermal stress and prevent damage to the semiconductor element. . However, with this structure, although the generation of thermal stress can be relaxed to some extent, the thermal stress at the joint between the power semiconductor element and the buffer electrode is not completely eliminated.

For example, when a GTO element is used as the power semiconductor element, its linear expansion coefficient is about 3 × 10 ⁻⁶ / K, whereas the linear expansion coefficient of the buffer electrode is about 3 × 10 ⁻⁶ / K. It is 5 × 10 ⁻⁶ / K, and when it is made of tungsten, it is about 4 × 10 ⁻⁶ / K. Further, the thermal resistance between the members inside the module or the thermal resistance between the module and the cooling device cannot be reduced unless the pressure contact force is increased, but the power semiconductor element may be damaged if the pressure contact force is large. There was also a problem.

As means for alleviating the thermal stress due to such temperature change, for example, Japanese Patent Application Laid-Open No. 11-233696 discloses long-term reliability of a member serving as a heat conduction path inside a power semiconductor module, and the semiconductor module. A structure for improving cooling performance is disclosed. In this structure, a low melting point material having a melting point lower than the maximum operating temperature of the power semiconductor element is provided between the insulating substrate that serves as a heat conduction path inside the power semiconductor module and the heat radiating metal base plate, and the low melting point material contacts The surfaces of the insulating substrate and the metal base plate for heat dissipation are each coated with an anticorrosive member, and a high-contact member having good contact with the low-melting point material is further coated thereon to form a two-layer coating. As a result, the thermal stress between the members is eliminated, the long-term reliability is improved, the cooling performance of the power semiconductor element is improved, and alloying of the low melting point material is suppressed.

Regarding the pressure contact stack type module, for example, Japanese Patent Application Laid-Open No. 5-267491 discloses a pressure contact type semiconductor device and a power conversion device using the same. In this publication, a soft layer made of a soft material is provided between the semiconductor substrate and the buffer electrode, between the buffer electrode and the main electrode, and further between the semiconductor substrate and the main power to reduce thermal stress and reduce the stress. It is shown that the pressure resistance reduces the thermal resistance.

Further, as another prior disclosure example of another pressure contact stack type module, for example, Japanese Patent Laid-Open No. 6-
Japanese Patent No. 37219 discloses a power semiconductor cooling device. According to this structure, a cold plate having a coolant passage inside the stacking plate is stacked on the power semiconductor device and is stacked on the power semiconductor device for a stack assembly formed by stacking a plurality of flat power semiconductor devices. The refrigerant circulation path to and from the plate is composed of a pipe made of an electrically insulating material, and the refrigerant is forcibly circulated to radiate the heat generated in the semiconductor to the outside of the system through a radiator to cool it.

[0013]

Since the conventional semiconductor module is constructed as described above, it is disclosed in Japanese Patent Laid-Open No. 11-2.
In the structure disclosed in Japanese Patent No. 33696, cooling is performed from one side of the power semiconductor element of the heat source, so that basically the same heat conduction path as in the conventional case is formed, and furthermore, the coating is provided in a plurality of layers. As a result, the number of man-hours is increased and there is a problem in cost.

Further, in the structure disclosed in Japanese Patent Laid-Open No. 5-267491, the soft layer is arranged between the members, but there is a problem that the thermal stress is not completely eliminated by this structure. Furthermore, in the pressure contact stack type structure disclosed in Japanese Patent Laid-Open No. 6-37219, a member that conducts electric power of the power semiconductor and a member that also transfers heat of the power semiconductor are composed of independent individual members. As a result, the number of parts increases, the structure becomes complicated, and the number of assembling steps increases.

The present invention has been made in order to solve the above-mentioned problems, and eliminates the thermal stress between the members forming the heat conduction paths inside the power semiconductor module, so that the power semiconductor module The reliability can be continued for a long time, and further, the thermal resistance between each member that becomes a heat conduction path inside the power semiconductor module and the thermal resistance between the power semiconductor module and the cooling device can be reduced. An object of the present invention is to provide a semiconductor module that can be manufactured.

[0016]

A semiconductor module according to claim 1 of the present invention is one in which a semiconductor element is sealed, and an input portion and an output portion of the semiconductor element are electrically and thermally conductive. An electrode made of a high metal material is brought into surface contact, a semiconductor element and an electrode have a laminated structure, and an elastic member for pressing the laminated members together in the laminating direction is provided.

In the semiconductor module according to the second aspect of the present invention, the coil spring serving as an electrode is pressed against the semiconductor element, and one end of the coil spring is fixed to the control board.

According to a third aspect of the present invention, a semiconductor module is provided with a guide member having a truncated cone shape for positioning a coil spring.

According to a fourth aspect of the present invention, a semiconductor module is provided with a positioning member for determining the position of the laminated member and a gap between the members.

According to a fifth aspect of the present invention, the semiconductor module is such that the electrodes are provided with fins for heat dissipation.

According to a sixth aspect of the present invention, a semiconductor module is provided with a through hole through which a cooling medium passes and an uneven fin is provided on the inner wall of the through hole.

In the semiconductor module according to the seventh aspect of the present invention, a cavity is provided in the electrode, and a working fluid for transferring heat is sealed in the cavity.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. An embodiment of the present invention will be described below with reference to the drawings. 1 is a plan view showing an IGBT module according to Embodiment 1 of the present invention,
2 is a side view seen from the direction A in FIG. 1, and FIG. 3 is a front view seen from the direction B in FIG. In the figure, 1 is an IGBT module, 2 is an electrode which is in surface contact with the collector portion of one IGBT element made of copper, aluminum or the like, and has a fin 3 for heat dissipation.

The other IGBT 4 is made of copper or aluminum.
The electrode is in contact with the emitter section of the device and has a fin 3 for heat dissipation, similar to the electrode 2. When the electrode 2 is in contact with the collector part of the IGBT element, 5 serves as an emitter part when it functions as a collector, and further, the electrode 4 has an IGBT part.
It is a shared electrode that comes into contact with the emitter of the T element and serves as a collector when it functions as an emitter, and is provided with a fin 3 for heat dissipation similar to the electrodes 2 and 4.

Further, 6 is a module main body in which each component is embedded, 7 is a control board for controlling the switch signal of the IGBT element, and 8 is an electrode for transmitting the switch signal of the IGBT element to the gate portion or the base portion of the IGBT element. , Made of coil spring made of tin plated spring steel.

FIG. 4 is a cross-sectional plan view taken along the line CC in FIG. 2. In the figure, 9 is an IGBT element, 10 is a gate portion, 11 is a flywheel diode, and
It is paired with the T element 9.

The electrode 2 has a function of guiding a positive voltage from a battery (not shown) to the collector portion of the IGBT element 9 when a motor (not shown) to be controlled acts as an electric motor. When the gate signal of the IGBT element 9 with which the electrode 2 is in contact is ON, a positive voltage of the battery is emitted from the emitter, the electrode 5 guides it, and a current is supplied to the field coil (not shown) of the motor (not shown). introduce.

On the contrary, when the motor acts as a generator and the generator stores electricity in the battery during regenerative braking, the current generated in the field coil (not shown) of the generator (not shown) is used as an electrode. When guided by 5, the electrode 5 functions as a collector portion of the IGBT element and supplies a positive voltage from the generator. At this time, if the gate signal of the IGBT element in contact with the electrode 5 is ON, a positive potential is applied from the emitter by the electrode 4, and the current is transmitted to the secondary battery (not shown).

FIG. 5 is a side sectional view taken along the line DD in FIG. 1, in which 12 is a gate portion 1 of the IGBT element 9.
A guide member having a truncated right circular cone shape for guiding the coil spring 8 serving as the zero electrode to a desired position. And
Coil spring 8 fixed to control board 7 and serving as a gate electrode
However, when it is assembled to the module body 6, the truncated right circular cone shaped guide member 1 fixed to the module body 6 side.
While following the slope of No. 2 and the center of the coil spring 8,
Since the center of the gate portion 10 of the T element 9 is automatically aligned with the conical axis 12a of the truncated right circular cone-shaped guide member 12, the coil spring 8 and the gate portion 10 are aligned.
It is not necessary to make a delicate position adjustment, and the coil spring 8 can be assembled so that the coil spring 8 contacts the gate portion 10 easily, at high speed, and reliably.

Further, 13 is a spring composed of a leaf spring or the like, which generates a pressing force in a state where the IGBT element 9 and the flywheel diode 11 and the electrodes 2, 4 and 5 are laminated. Element 9 and electrode 2,
Enables electrical conduction of 4, 5 and IGBT
The heat generated by the element 9 and the flywheel diode 11 is
It can be adapted to communicate with the electrodes 2, 4, 5.

FIG. 6 is a front sectional view taken along the line EE in FIG. 2. In the drawing, 14 is each layer of the laminated structure inside the power semiconductor module, and the IGBT element 9, the flywheel diode 11 and the electrodes 2, 4, 5 are provided. Is a positioning plate member for determining the position of the. The positioning member 14 has a thickness substantially equal to that of the members forming the IGBT element 9 and the like in the stacking direction, and more accurately has a size that is slightly (about 10 to 100 μm) thinner.
It is made of a material that is electrically insulated and has excellent thermal conductivity. For example, a ceramic (internal resistance of about 10
¹⁰ Ωm, thermal conductivity 170 W / mK, linear expansion coefficient about 4.5 × 10 ⁻⁶ / K) and porcelain (internal resistance about 10 ¹¹ Ω)
m, thermal conductivity 1.5 W / mK, linear expansion coefficient about 4.5 x 1
Consists 0 ^-6 / K), for positioning so as to surround the periphery of the member constituting the IGBT element 9 or the like.

At this time, in each layer, each functional member such as the IGBT element 9 and the positioning member 14 have a gap x therebetween and are arranged adjacent to each other. This gap x is determined by the IGBT element 9
And the linear expansion coefficient of silicon, which is the main material forming the semiconductor element of the flywheel diode 11, is approximately 2.4 × 10.
^-6 / K, the linear expansion coefficient of the plate-shaped positioning member 14 is about 4.5 × 10 ^-6 / K, and the linear expansion coefficient of copper forming the electrodes 2, 4, 5 is about 16.7 × 10 ^{−. 6} / K or a linear expansion coefficient of aluminum of about 23 × 10 ⁻⁶ / K, etc., provided to secure a space for absorbing a difference in expansion due to different materials.

Reference numeral 15 denotes a case, which, like the plate-shaped positioning member 14, is made of a material having excellent electrical insulation and thermal conductivity, and constitutes the lower portion of the outer shell of the power semiconductor module. The cover 16 constituting the upper portion of the outer shell is fitted to each other to form the outer shell of the power semiconductor module and form the module body 6.

As described above, in the power semiconductor module according to the present invention, a conductive welding member such as solder is not welded between the members serving as power and heat conduction paths inside the power semiconductor module, and the power semiconductor element is not welded. Since the electrodes 2, 4, and 5 made of a metal material having excellent electrical conductivity and thermal conductivity are directly brought into surface contact with the power input section and the power output section of the above, the electrical conductivity and the thermal conductivity are exerted. It is possible to secure long-term reliability of the power semiconductor module without causing thermal stress between the members due to the generated heat, while securing the electric power conduction function.

Further, in the power semiconductor module according to the present clarification, the members serving as electric power and heat conduction paths inside the power semiconductor module have a laminated structure, and the spring 13 for pressing the laminated members in the laminating direction. Since an elastic member made of is provided, desired electrical conductivity and thermal conductivity (thermal resistance),
Further, it becomes possible to set and maintain the mechanical durability, so that the life of the power semiconductor element can be extended and the reliability can be secured for a long time.

Further, in the bower semiconductor module according to the present invention, the coil spring 8 formed of a conductive material is formed as an electrode for transmitting a signal for energization and interruption in the gate portion 10 or the base portion of the power semiconductor element. Since the coil spring 8 is pressed and brought into electrical connection, electrical conduction is enabled, so that thermal stress is not generated between the members due to the generated heat while maintaining the original conductive function, and the long-term reliability of the power semiconductor element is ensured. The sexuality is dramatically improved. Furthermore, in order to fix the coil spring 8 to the control board 7 side,
The power semiconductor element does not need to be separately provided with a member serving as an electrode for transmitting a signal for energization and an interruption, and the structure is simplified,
The manufacturing cost of the power semiconductor device can be suppressed.

In the power semiconductor module according to the present invention, the center of the gate portion 10 or the base portion of the power semiconductor element is aligned with the central axis of the power semiconductor element, and the shape of the coil spring 8 serving as the gate electrode or the base electrode is adjusted. Since the guide member 12 having a truncated right circular cone shape is provided, it is not necessary to adjust the positions of the gate portion 10 or the base portion of the power semiconductor element and the coil spring 8 serving as an electrode during assembly.
Since the assemblability is simplified, the manufacturing cost can be suppressed.

Further, in the power semiconductor module according to the present invention, since the guide member 12 having a truncated right circular cone shape is fixed to the laminated structure side of the power semiconductor module body, the central axis 12a of the truncated right circular cone and the power semiconductor. Since the structure is such that the position of the gate portion 10 or the base portion of the power semiconductor element matches, it is not necessary to adjust the position of the gate portion 10 or the base portion of the power semiconductor element and the coil spring 8 serving as the electrode at the time of assembly, and the assembly is simple. Therefore, the manufacturing cost can be suppressed.

Further, in the power semiconductor module according to the present invention, in the laminated structure of the power semiconductor module, since the gap x is provided between a plurality of adjacent members in the same layer, the heat between the members due to expansion and contraction due to thermal change is generated. No stress is generated and the long-term reliability of the power semiconductor module is improved.

Further, the power semiconductor module according to the present invention is a metal member excellent in electrical conductivity and thermal conductivity that is brought into surface contact with the power input section and the power output section of the power semiconductor element, and the metal member (electrode) is used for heat dissipation. Since the cooling performance is improved by providing the fin 3, the life of the power semiconductor element can be extended and the reliability can be secured for a long period of time.

Embodiment 2. In the structure of the IGBT module according to the first embodiment of the present invention as described above, although the conductive function of the power semiconductor module can be secured with a relatively small number of types of members, the efficiency of cooling the power semiconductor element is low. It's not good. This is because the heat flux transferred from the power semiconductor element, which is a heat source, once passes through the cross section of the electrodes 2, 4 and 5 and moves to a portion where the heat radiation fin 3 is present.

A thermal resistance Rth is generated during the movement of the heat flow east, and the thermal resistance Rth is represented by the following equation: Rth = D / λS D: Heat moving distance [m] λ: Thermal conduction Rate [W / m · K] S: cross-sectional area [m ² ] of a path along which heat travels, which is proportional to the moving distance D and inversely proportional to the cross-sectional area S of a member through which a heat flux passes. This is the same as the electrodes 2, 4, 5 of the IGBT module according to the first embodiment of the present invention.
In the case of a relatively thin and flat member, the heat transfer distance D becomes long and the cross-sectional area S becomes small.
This is because the value of h is inevitably high.

Further, simply increasing the size of the member in order to increase the cross-sectional area S is contrary to the original purpose of the module, that is, size reduction and cost reduction. When the value of the thermal resistance Rth becomes high, the temperature of the member of the transmission path rises proportionally in the steady state, and the temperature of the power semiconductor element as the heat source is also maintained at a higher temperature than the temperature of the member of the transmission path. Become. Therefore, the thermal resistance Rth is set by keeping the cross-sectional area S as wide as possible so that the heat flux can pass while suppressing the heat moving distance D to the minimum.
In order to minimize the above, in the second embodiment, the cooling structure incidental to the electrode is devised.

FIG. 7 shows an IG according to the second embodiment of the present invention.
FIG. 8 is a plan view showing the BT module, FIG. 8 is a side view seen from the F direction in FIG. 7, and FIG. 9 is a front view seen from the G direction in FIG. In the figure, 21 is an IGBT module, 22 is an electrode in contact with the collector part of an IGBT element made of copper, aluminum, or the like, which is a pipe that transmits a cooling medium and is made of an electrically insulating material ( A nipple 23, which is not shown) and which is integrated by fitting and fitting, is pressed into the electrode 22.

Reference numeral 24 denotes an electrode which is in contact with the emitter of the IGBT element made of copper, aluminum or the like, and like the electrode 22, the nipple 23 for the refrigerant is press-fitted. When the electrode 22 contacts the collector part of the IGBT to function as a collector, the electrode 25 becomes an emitter part.
It is a common electrode that serves as a collector when it functions as an emitter by contacting the emitter of the GBT element.
Like the electrodes 22 and 24, the nipple 23 for the refrigerant is press-fitted.

Further, 26 is a module main body in which each component is embedded, 27 is a control board for controlling the switch signal of the IGBT element, and 28 is an IGBT element for the switch signal of the IGBT element.
The electrode that transmits to the gate part is made of a coil spring made of tin plated spring steel.

FIG. 10 is a sectional plan view taken along the line HH in FIG. 8, and FIG. 11 is a sectional plan view taken along the line I-I in FIG.
In the figure, 29 is an IGBT element, 30 is a gate portion, 3
Reference numeral 1 is a flywheel diode, which is an IGBT element 29.
And are configured in pairs. The electrode 22 has a function of guiding a positive voltage from a battery (not shown) to the collector portion of the IGBT element when a motor (not shown) to be controlled acts as an electric motor. And the electrode 22
When the gate signal of the IGBT element in contact with is ON, the positive potential of the battery is emitted from the emitter, the electrode 25 guides it, and the current is transmitted to the field coil (not shown) of the motor (not shown).

On the contrary, in the case where the motor acts as a generator and the generator acts on the battery during regenerative braking, FIG.
The other IGBT element 29 described in No. 1 will function. That is, when the electrode 25 guides a current generated in a field coil (not shown) of a generator (not shown), the electrode 25 functions as a collector portion of the IGBT element and supplies a positive voltage from the generator. At this time, the electrode 25
When the gate signal of the IGBT element in contact with is ON, a positive potential is applied from the emitter by the electrode 24, and current is transmitted to the secondary battery (not shown) to charge the secondary battery.

FIG. 12 is a side sectional view taken along the line JJ in FIG. 7. In FIG. 12, reference numeral 32 denotes a frustoconical truncated cone for guiding the coil spring 28, which is an electrode of the gate portion 30 of the IGBT element 29, to a desired position. It is a guide member having a shape. This is because when the coil spring 28 fixed to the control substrate 27 and serving as the gate electrode is assembled to the module main body 26, the coil spring 28 follows the slope of the truncated right circular cone-shaped guide member 32 fixed to the module main body 26 side. Since the center of the coil electrode spring 28 and the center of the gate portion 30 of the IGBT element 29 are automatically aligned so as to be coaxial with the conical shaft 32a of the truncated right circular cone-shaped guide member 32, the coil spring The delicate position adjustment between the gate 28 and the gate portion 30 is not necessary, and the coil spring 28 can be assembled so that the coil spring 28 contacts the gate portion 30 easily, at high speed, and reliably.

Further, 33 is a spring composed of a leaf spring or the like, and includes an IGBT element 29 and a flywheel diode 31,
A pressing force is generated in a state where the electrodes and the electrodes 22, 24, 25 are laminated, and this enables electrical conduction between the IGBT element 29 and the electrodes 22, 24, 25, and at the same time the IGBT element 29 and the fly. Wheel diode 31
It is possible to transfer the heat generated at the electrodes 22, 24, 25 to the electrodes.

FIG. 13 is a front sectional view taken along the line KK in FIG. 8. In the figure, 34 is each layer of the laminated structure inside the power semiconductor module, which is an IGBT element 29, a flywheel diode 31, and electrodes 22, 24 and 25. Is a positioning member for determining the position of. The positioning member 34 has a thickness substantially equal to that of the members forming the IGBT element 29 and the like in the stacking direction.
More precisely, it has a dimension that makes it slightly (about 10 to 100 μm) thinner, and is made of a material that is electrically insulated and has excellent thermal conductivity. For example, a ceramic (internal resistance: about 10 ¹⁰ Ωm, heat resistance: Conductivity 170 W / mK, linear expansion coefficient about 4.5 × 10 ^-6 / K and porcelain (internal resistance about 10)
¹¹ Ωm, thermal conductivity 1.5 W / mK, linear expansion coefficient about 4.
5 × 10 ⁻⁶ / K), and the positioning is performed so as to surround the members constituting the IGBT element 29 and the like.

At this time, the IGBT element 29 is formed in each layer.
Each of the functional members such as the above and the positioning member 34 have a gap x therebetween and are arranged adjacent to each other. This gap x is determined by the IGBT element 2
9 and the linear expansion coefficient of silicon, which is the main material forming the semiconductor elements of the flywheel diode 31, of about 2.4 × 10.
^-6 / K and the linear expansion coefficient of the plate-like positioning member 34 is about 4.
5 × 10 ⁻⁶ / K, further, the linear expansion coefficient of copper constituting the electrodes 22, 24, 25 is about 16.7 × 10 ⁻⁶ / K, or the linear expansion coefficient of aluminum is about 23 × 10 ⁻⁶ / K, etc. It is provided to secure a space for absorbing a difference in expansion due to different materials.

Reference numeral 35 designates a case, which, like the plate-like positioning member 34, is made of a material having excellent electric insulation and thermal conductivity and constitutes the lower part of the outer shell of the power semiconductor module. The cover 36 forming the upper part of the outer shell is fitted with each other to form the outer shell of the power semiconductor module and form the module body 26.

FIG. 14 is a front sectional view taken along the line LL in FIG. 8. In FIG. 14, reference numeral 37 is a through hole through which a cooling medium penetrating the inside of the electrodes 22, 24 and 25 passes. FIG. 15 is an enlarged view showing the sectional shape of the through hole 37. As shown in FIG. 15, an uneven fin 38 is provided on the inner wall of the through hole 37 in order to increase the contact area with the refrigerant. The uneven fins 38 increase the contact area, suppress the thermal resistance Rth, and improve the heat transfer performance. Since the cooling performance is enhanced in this way, the life of the power semiconductor element can be extended and the reliability can be secured for a long period of time.

Then, it is conceivable to use air, which is an electrically insulating material, or a fluorocarbon liquid, etc., as the cooling refrigerant passing through the through holes 37.

Embodiment 3. In the present embodiment, a heat pipe is applied to the electrodes in order to transfer heat more rapidly and efficiently perform heat exchange. 16 is a plan view showing an IGBT module according to Embodiment 3 of the present invention, FIG. 17 is a side view seen from the M direction in FIG. 16, and FIG. 18 is FIG.
It is the front view seen from N direction. In the figure, 41 is I
The GBT module 42 is a heat pipe having an outer shell made of copper and also serves as an electrode in contact with the collector portion of one IGBT element. The heat radiating portion of the heat pipe 42 has fins 43 for radiating heat.

A heat pipe 44 made of steel also serves as an electrode in contact with the emitter of the other IGBT element. Like the heat pipe 42, the fin 43 for heat dissipation is used.
Have. Reference numeral 45 serves as an emitter section when the electrode 42 contacts the collector of the IGBT element to function as a collector. Further, when the electrode 44 contacts the emitter section of the IGBT element, it serves as a collector section. Electrodes, which are also made of copper, also serve as heat pipes, and have fins 43 for heat dissipation.

Further, 46 is a module main body in which the respective parts are embedded, 47 is a control board for controlling the switch signal of the IGBT element, and 48 is an IGBT element for the switch signal of the IGBT element.
It is an electrode that transmits to the gate of the device, and is made of a coil spring made of tinned spring steel.

FIG. 19 is a cross-sectional plan view taken along the line OO in FIG. 17, in which 49 is an IGBT element and 50 is an element.
Is a gate portion, 51 is a flywheel diode, and
It is paired with the GBT element 49.

The electrode 42 has a function of guiding a positive voltage from a battery (not shown) to the collector portion of the IGBT element 49 when a motor (not shown) to be controlled acts as an electric motor. Then, the I that the electrode 42 contacts
When the gate signal of the GBT element 49 is ON, the positive voltage of the battery is emitted from the emitter and the electrode 45 guides it.
A current is transmitted to a field coil (not shown) of a motor (not shown).

On the other hand, when the motor acts as a generator and the generator stores electricity in the battery during regenerative braking, the current generated in the field coil (not shown) of the generator (not shown) is applied to the electrode. The electrode 45 is guided by the IGB 45.
It functions as a collector of the T element 49 and supplies a positive voltage from the generator. At this time, if the gate signal of the IGBT element 49 in contact with the electrode 45 is ON, a positive potential is applied from the emitter by the electrode 44, and a secondary battery (not shown)
F and current is transmitted.

FIG. 20 is a side sectional view taken along the line P--P in FIG. 16, in which reference numeral 52 denotes a frustoconical truncated cone for guiding the coil spring 48 serving as the electrode of the gate portion 50 of the IGBT element 49 to a desired position. It is a guide member having a shape.
This is because when the coil spring 48, which is fixed to the control substrate 47 and serves as a gate electrode, is attached to the module main body 46, the coil spring 48 follows the slope of the truncated right circular cone-shaped guide member 52 fixed to the module main body 46 side. Coil spring 48
And the center of the gate part 50 of the IGBT element 49 are
Since the guide member 52 having a truncated cone shape is automatically aligned so as to be coaxial with the conical shaft 52a, fine adjustment of the position of the coil spring 48 and the gate portion 50 is unnecessary, and it is simple, fast, and fast. The gate spring 50 can be assembled so that the coil spring 48 is surely brought into contact with the gate portion 50.

Further, 53 is a spring composed of a leaf spring or the like, which includes an IGBT element 49 and a flywheel diode 51,
A pressing force is generated in a state where the electrodes and the electrodes 42, 44 and 45 are laminated, which enables electrical connection between the IGBT element 49 and the electrodes 42, 44 and 45, and at the same time, the IGBT element 49 and the flywheel. The heat generated by the diode 51 can be transferred to the electrodes 42, 44, 45.

FIG. 21 is a front sectional view taken along the line Q-Q in FIG. 17, in which 54 denotes each layer of the laminated structure inside the power semiconductor module, the IGBT element 49, the flywheel diode 51 and the electrodes 42, 44 and 45.
Is a positioning plate member for determining the position of the. The positioning plate member 54 has a thickness substantially equal to that of the members forming the IGBT element 49 and the like in the stacking direction, and more precisely has a dimension of slightly thinning (about 10 to 100 μm), and has an electrical property. It is made of a material that is electrically insulated and has excellent thermal conductivity. For example, a ceramic (internal resistance of about 10 ¹⁰ Ωm, thermal conductivity of 170 W / m.
K, linear expansion coefficient about 4.5 × 10 ⁻⁶ / K) and porcelain (internal resistance about 10 ¹¹ Ωm, thermal conductivity 1.5 W / m · K, linear expansion coefficient about 4.5 × 10 ⁻⁶ / K). ), The above IGB
Positioning is performed so as to surround the members that form the T element 49 and the like.

At this time, the IGBT element 49 is formed in each layer.
The respective functional members such as the above and the positioning member 54 have a gap x therebetween and are arranged adjacent to each other. This gap x is determined by the IGBT element 4
9 and the linear expansion coefficient of silicon, which is the main material forming the semiconductor elements of the flywheel diode 51, of about 2.4 × 10.
^-6 / K, the linear expansion coefficient of the plate-shaped positioning member 54 is about 4.5 * 10 < ^-6 > / K, and the linear expansion coefficient of copper forming the electrodes 42, 44, 45 is about 16.7 * 10 < ^- >. ⁶ / K or a linear expansion coefficient of aluminum of about 23 × 10 ⁻⁶ / K, etc., provided to secure a space for absorbing a difference in expansion due to different materials.

Reference numeral 55 denotes a case, which, like the plate-shaped positioning member 54, is made of a material having excellent electrical insulation and thermal conductivity and constitutes the lower part of the outer shell of the power semiconductor module. The cover 56 forming the upper part of the outer shell is fitted and included in each other to form the outer shell of the power semiconductor module and form the module main body 46.

As shown in FIG. 20, the electrodes 42, 44 and 45 are provided with a cavity 57 therein, and a capillary tissue called a wick (not shown) is formed on the inner wall surface of the cavity 57. A liquid that moves heat, which is called a working liquid (not shown), is enclosed in the inner space. The heat generated by the IGBT element 49 and the flywheel diode 51 is transferred to the electrodes 42, 44, 45 which also function as a heat pipe which is a heat conductor, and transferred to the wall of the heat input part of the heat pipe. As a result, the working fluid enclosed in the cavity 57 inside the heat pipe is heated and evaporated.

The vapor obtained by this vaporization moves from the heat input portion of the heat pipe to the heat radiating portion, releases heat in the heat radiating portion, condenses, and returns to the working fluid again. The latent heat released from the vapor is transferred to the fins 43 of the heat radiating portion of the heat pipe and released into the air. Further, the working fluid flows back from the heat radiating portion of the heat pipe to the heat input portion.

The power semiconductor element described in each of the above embodiments is not limited to the IGBT element.
Besides IGBT element, diode, thyristor, triac, MOSFET, bipolar transistor, SIT
Etc., or a mixture of these may be used.

As described above, the power semiconductor module according to the present invention is provided with a metal member having excellent conductivity and thermal conductivity, which is brought into surface contact with the power input section and the power output section of the power semiconductor element, and the metal member is heated. Since it also functions as a pipe, the power semiconductor element serving as a heat source is not cooled by interposing a plurality of different members, but the metal member (electrode) itself also serves as a cooling function. The simplification can be achieved, and the effect of significantly reducing the cost for manufacturing the power semiconductor module can be obtained.

Further, by constructing a passage for a refrigerant that absorbs and moves heat in this metal member (electrode), it becomes possible to greatly suppress the thermal resistance, and the life of the power semiconductor element is prolonged and the reliability is long-term. It is possible to further improve the property. Further, since the cooling performance is improved by providing the fins 43 for heat dissipation on the metal member (electrode), it becomes possible to further prolong the life of the power semiconductor element and further improve the long-term reliability.

[0072]

According to the semiconductor module of the first aspect of the present invention, the semiconductor element is sealed inside, and the input portion and the output portion of the semiconductor element are made of metal having high conductivity and thermal conductivity. Since the electrodes made of materials are brought into surface contact, the semiconductor element and the electrodes have a laminated structure, and elastic members for pressing the laminated members in the laminating direction are provided, thermal stress between the members is not generated by the generated heat. In addition, desired electrical conductivity, thermal conductivity, and mechanical durability can be maintained, the life of the semiconductor element can be extended, and long-term reliability can be ensured.

According to the semiconductor module of the second aspect of the present invention, since the coil spring serving as the electrode is pressed against the semiconductor element and one end of the coil spring is fixed to the control substrate, the structure is simplified and the manufacturing cost is reduced. Can be suppressed.

According to the semiconductor module of the third aspect of the present invention, since the guide member having the truncated cone shape for positioning the coil spring is provided, the assembly can be easily performed.

According to the semiconductor module of the fourth aspect of the present invention, since the positioning member for determining the position of the laminated member is provided and the gap is provided between the respective members,
The thermal stress between members does not occur.

According to the semiconductor module of the fifth aspect of the present invention, since the fins for radiating heat are provided on the electrodes, the cooling performance can be improved.

According to the semiconductor module of the sixth aspect of the present invention, the through hole for passing the cooling medium is provided inside the electrode, and the fin having the uneven shape is provided on the inner wall of the through hole. Performance can be improved.

According to the semiconductor module of the seventh aspect of the present invention, since the electrode is provided with the cavity and the working liquid for moving the heat is enclosed in the cavity, the cooling performance can be enhanced.

[Brief description of drawings]

FIG. 1 is a plan view showing a semiconductor module according to a first embodiment of the present invention.

FIG. 2 is a side view seen from the direction A in FIG.

FIG. 3 is a front view seen from the direction B in FIG.

FIG. 4 is a cross-sectional plan view taken along the line CC in FIG.

5 is a cross-sectional side view taken along the line DD in FIG.

6 is a sectional front view taken along line EE in FIG.

FIG. 7 is a plan view showing a semiconductor module according to a second embodiment of the present invention.

FIG. 8 is a side view seen from the F direction in FIG.

9 is a front view seen from the direction G in FIG. 7. FIG.

10 is a cross-sectional plan view taken along the line HH in FIG.

11 is a cross-sectional plan view taken along the line I-I of FIG.

12 is a cross-sectional side view taken along line JJ in FIG.

13 is a sectional front view taken along line KK in FIG.

14 is a sectional front view taken along line LL in FIG.

FIG. 15 is an enlarged view showing a through hole portion.

FIG. 16 is a plan view showing a semiconductor module according to a third embodiment of the present invention.

FIG. 17 is a side view seen from the M direction in FIG.

FIG. 18 is a front view seen from the N direction in FIG.

19 is a cross-sectional plan view taken along line OO in FIG.

20 is a cross-sectional side view taken along line P-P in FIG.

21 is a sectional front view taken along the line QQ in FIG.

FIG. 22 is a sectional view showing a conventional semiconductor module.

[Explanation of symbols]

2, 4, 5, 22, 24, 25, 42, 44, 45 electrodes, 3,43 fins, 7, 27, 47 control board,
8, 28, 48 Coil spring, 12, 32, 52 Guide member, 13, 33, 53 Elastic member, 14, 34, 54
Positioning member, 37 through holes, 57 cavities.

Claims (7)

[Claims] 1. A semiconductor module having a semiconductor element sealed inside, wherein an electrode made of a metal material having high electrical conductivity and thermal conductivity is brought into surface contact with an input portion and an output portion of the semiconductor element, A semiconductor module, wherein the semiconductor element and the electrode have a laminated structure, and an elastic member for pressing the laminated members against each other in the laminating direction is provided. 2. The semiconductor module according to claim 1, wherein a coil spring serving as an electrode is pressed into contact with the semiconductor element and one end of the coil spring is fixed to a control board. 3. The semiconductor module according to claim 2, further comprising a guide member having a truncated cone shape for positioning the coil spring. 4. The semiconductor according to claim 1, wherein a positioning member for determining the position of the laminated member is provided, and a gap is provided between each member. module. 5. The semiconductor module according to claim 1, wherein the electrode is provided with a fin for heat dissipation. 6. A through hole for allowing a cooling medium to pass therethrough is provided inside the electrode, and an uneven fin is provided on the inner wall of the through hole. The semiconductor module according to any one of 1. 7. The semiconductor module according to claim 1, wherein a cavity is provided in the electrode, and a working liquid for transferring heat is sealed in the cavity. .