阅读说明：本技术 功率模块以及电力变换装置 (Power module and power conversion device ) 是由 近藤聪 藤野纯司 松井智香 于 2019-06-21 设计创作，主要内容包括：本发明提供对在金属配线之下形成孔洞进行了抑制的功率模块。具备：半导体元件；基板,其搭载半导体元件；接线部,其由多个配线的队列构成；壳体,在其底面侧配置基板,该壳体收容半导体元件以及接线部；以及绝缘封装材料,其填充在壳体内,构成接线部的多个配线以在相同的方向成环,各自的配线高度至少朝向队列的一个方向而逐渐地变高的方式配置。(The invention provides a power module which suppresses the formation of holes under metal wiring. The disclosed device is provided with: a semiconductor element; a substrate on which a semiconductor element is mounted; a wiring section configured from a line of a plurality of wires; a case in which a substrate is disposed on a bottom surface side and which houses the semiconductor element and the wiring portion; and an insulating sealing material filled in the housing, wherein a plurality of wires constituting the wire connection portion are looped in the same direction, and the respective wire heights are arranged so as to gradually increase toward at least one direction of the array.)

1. A power module is provided with:

a semiconductor element;

a substrate on which a semiconductor element is mounted;

a wiring section configured from a line of a plurality of wires;

a case in which the substrate is disposed on a bottom surface side thereof, the case accommodating the semiconductor element and the wire connecting portion; and

an insulating encapsulation material filled in the case,

the plurality of wires constituting the wire connecting portion are arranged in a loop in the same direction, and the heights of the wires are gradually increased toward at least one direction of the queue.

2. The power module of claim 1,

the plurality of wires of the wire connecting portion are arranged so that the wire height is the lowest at the center portion of the queue and gradually increases from the center portion toward the 1 st direction of the queue, and are arranged so as to gradually increase toward the 2 nd direction opposite to the 1 st direction.

3. The power module of claim 1,

the plurality of wires of the wire connecting portion are arranged so that the wire interval is wider than other portions and the wire height is the highest at the center portion of the queue, and gradually decreases from the center portion toward the 1 st direction of the queue, and gradually decreases toward the 2 nd direction opposite to the 1 st direction.

4. The power module of claim 1,

the plurality of wires of the wire connecting portion are arranged such that the wire interval is wider than other portions and the wire height is the lowest at the center portion of the queue, and gradually increases from the center portion toward the 1 st direction of the queue, and gradually increases toward the 2 nd direction opposite to the 1 st direction.

5. The power module of claim 1,

the plurality of wires of the wire connecting portion are arranged so that the wire interval is wider than other portions and the wire height is the highest at the center portion of the queue and gradually decreases from the center portion toward the 1 st direction of the queue, and are arranged so as to gradually decrease toward the 2 nd direction opposite to the 1 st direction, and are arranged so as to be inclined in the 1 st direction and the 2 nd direction, respectively, with the center portion as a boundary in a plan view.

6. The power module of any of claims 1-5,

the plurality of wires of the wire connecting portion include double wires arranged so that the wires are overlapped in a loop forming direction.

7. The power module of any of claims 1-5,

the plurality of wires in the wire connecting portion are made uniform in inductance by making the wire length of the wire having the highest wire height the shortest in plan view, making the wire length of the wire having the lowest wire height the longest in plan view, and making the total lengths of the wires the same.

8. The power module of any of claims 1-5,

the wiring portion is provided at least in a portion that electrically connects the semiconductor element and a main electrode terminal through which a main current flows in the semiconductor element, between the semiconductor elements, and between conductor patterns on the substrate.

9. A power conversion device is provided with:

a main conversion circuit having the power module according to claim 1, the main conversion circuit converting and outputting the input electric power; and

and a control circuit that outputs a control signal for controlling the main converter circuit to the main converter circuit.

Technical Field

The present invention relates to a power module, and more particularly, to a power module in which formation of a hole in an insulating encapsulating material filled in a case is suppressed.

Background

A circuit is formed by electrically connecting a semiconductor element and a circuit pattern on an insulating substrate with metal wires or the like in a normal power module, but the number of metal wires connected to the semiconductor element tends to increase and the arrangement density of the metal wires increases with the increase in density and reliability in the power module, and for example, as disclosed in fig. 9A of patent document 1, a power module employing staggered bonding in which bonding is performed by shifting the bonding position little by little is increasing.

Patent document 1: japanese Kokai publication 2007-502544

However, if the number of metal wirings in the power module increases due to diversification of the rated value of the power module and increase in the current, there is a possibility that the wiring interval becomes narrow, bubbles contained in the insulating sealing material become difficult to be released from the gap of the metal wirings, the bubbles stay under the metal wirings, and finally, the bubbles remain as holes under the metal wirings.

Disclosure of Invention

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a power module in which formation of a void below a metal wiring is suppressed.

The power module according to the present invention includes: a semiconductor element; a substrate on which a semiconductor element is mounted; a wiring section configured from a line of a plurality of wires; a case in which the substrate is disposed on a bottom surface side thereof, the case accommodating the semiconductor element and the wire connecting portion; and an insulating sealing material filled in the case, wherein the plurality of wires constituting the wire connecting portion are looped in the same direction, and the respective wire heights are arranged so as to gradually increase toward at least one direction of the array.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the power module of the present invention, since the wiring height of each of the plurality of wires constituting the wiring portion is gradually increased toward at least one direction of the array, air bubbles in the insulating sealing material under the metal wire are easily discharged from under the metal wire, and formation of voids under the metal wire can be suppressed.

Drawings

Fig. 1 is a cross-sectional view of a power module according to embodiment 1 of the present invention.

Fig. 2 is a partial plan view of the power module according to embodiment 1 of the present invention as viewed from above.

Fig. 3 is a plan view illustrating an example 1 of an exhaust structure of a wire connection portion of a power module according to embodiment 1 of the present invention.

Fig. 4 is a sectional view illustrating an example 1 of an exhaust structure of a wire connection portion of a power module according to embodiment 1 of the present invention.

Fig. 5 is a schematic diagram for explaining a mechanism of the exhaust structure.

Fig. 6 is a plan view illustrating an example 2 of an exhaust structure of a wire connection portion of a power module according to embodiment 1 of the present invention.

Fig. 7 is a cross-sectional view illustrating an example 2 of an exhaust structure of a wire connection portion of a power module according to embodiment 1 of the present invention.

Fig. 8 is a plan view illustrating an example 3 of an exhaust structure of a wire connection portion of a power module according to embodiment 1 of the present invention.

Fig. 9 is a sectional view illustrating an example 3 of an exhaust structure of a wire connection portion of a power module according to embodiment 1 of the present invention.

Fig. 10 is a sectional view illustrating an example 3 of an exhaust structure of a wire connection portion of a power module according to embodiment 1 of the present invention.

Fig. 11 is a plan view illustrating an example 4 of an exhaust structure of a wire connection portion of a power module according to embodiment 1 of the present invention.

Fig. 12 is a sectional view illustrating an example 4 of an exhaust structure of a wire connection portion of a power module according to embodiment 1 of the present invention.

Fig. 13 is a plan view illustrating an example 5 of an exhaust structure of a wire connection portion of a power module according to embodiment 1 of the present invention.

Fig. 14 is a plan view illustrating an example 5 of an exhaust structure of a wire connection portion of a power module according to embodiment 1 of the present invention.

Fig. 15 is a sectional view illustrating an example 5 of an exhaust structure of a wire connection portion of a power module according to embodiment 1 of the present invention.

Fig. 16 is a plan view illustrating an example 6 of the exhaust structure of the wire connection portion of the power module according to embodiment 1 of the present invention.

Fig. 17 is a cross-sectional view illustrating an example 6 of the exhaust structure of the wire connection portion of the power module according to embodiment 1 of the present invention.

Fig. 18 is a plan view illustrating an application example of the exhaust structure of the wire connection portion of the power module according to embodiment 1 of the present invention to other portions.

Fig. 19 is a sectional view illustrating an application example of the exhaust structure to the other part of the wire connection part of the power module according to embodiment 1 of the present invention.

Fig. 20 is a plan view illustrating an application example of the exhaust structure of the wire connection portion of the power module according to embodiment 1 of the present invention to other portions.

Fig. 21 is a sectional view illustrating an application example of the exhaust structure to the other part of the wire connection part of the power module according to embodiment 1 of the present invention.

Fig. 22 is a block diagram showing a configuration of a power conversion device according to embodiment 2 of the present invention.

Description of the reference numerals

1 case, 2 main electrode terminals, 3 insulating substrate, 4 insulating packaging material, 5 metal wiring, 104 semiconductor element.

Detailed Description

< embodiment 1 >

Fig. 1 is a sectional view of a power module 100 according to embodiment 1 of the present invention. Fig. 2 is a partial plan view of the power module 100 as viewed from above, and the sealing resin and the like are omitted. Further, the section in the direction of the arrow at the line a-B-a in fig. 2 is the section of fig. 1.

As shown in fig. 1, in the power module 100, the insulating substrate 3 is bonded to the upper surface of the base plate 101 with solder (under-substrate solder) 107b, and the semiconductor element 104 including the switching element 104a and the flywheel diode 104b is bonded to the upper surface of the insulating substrate 3 (substrate) with solder 107 a. The base plate 101 is housed in an opening on the bottom surface side of the casing 1, the upper surface side and the bottom surface side of the casing 1 are openings, and the base plate 101 having the same shape and the same area as the opening on the bottom surface side constitutes the bottom surface of the casing 2.

In the insulating substrate 3, upper conductor patterns 103a and 103b are provided on an upper surface of an insulating material 103d, a lower conductor pattern 103e is provided on a lower surface, and the insulating material 103d is made of, for example, resin or Al₂O₃AlN and Si₃N₄Etc. ceramic material. In addition, a lead frame patterned with a circuit pattern may be used instead of the insulating substrate 3.

As the semiconductor element 104, for example, an igbt (insulated Gate Bipolar transistor) is used as the switching element 104 a. When a SiC (silicon carbide) -mosfet (metal oxide semiconductor Field Effect transistor) is used as the switching element 104a, a SiC-sbd (shottky Barrier diode) can be used as the flywheel diode 104 b. From SiC, Ga₂O₃Since a MOSFET made of a wide band gap semiconductor material such as GaN has a high withstand voltage and a high allowable current density, the MOSFET can be made smaller than a MOSFET made of a silicon semiconductor material, and the power module can be made smaller by incorporating the MOSFET.

The switching element 104a and the free wheel diode 104b are bonded to the upper conductor pattern 103a of the insulating substrate 3 by solder 107a, but a bonding material containing sintered Ag (silver) or Cu (copper) particles may be used, and the lifetime of the bonded portion can be improved by using a sintered bonding material as compared with the case of solder bonding. In the case of using a semiconductor device (SiC semiconductor device) using SiC that can operate at high temperatures, the characteristics of the SiC semiconductor device can be more effectively exhibited by using a sintered material to increase the life of the bonding portion.

A main electrode terminal 2 through which a main current flows is provided on a side surface of the case 1, and the main electrode terminal 2 extends from the side surface of the case 1 to an upper surface of the case 1 and is exposed to the outside on the upper surface of the case 1. Further, a control terminal 21 is provided on a side surface of the case 1 on which the main electrode terminal 2 is provided, and the control terminal 21 extends from the side surface of the case 1 to an upper surface of the case 1 and is exposed to the outside on the upper surface of the case 1.

In the case 1, the switching element 104a and the upper surface electrode 109 of the diode 104b, the upper surface electrode 109 of the diode 104b and the upper conductor pattern 103b, and the upper conductor pattern 103b and the main electrode terminal 2 are connected by a plurality of metal wirings 5. A control electrode (not shown) of the switching element 104a is connected to the control terminal 21 via the metal wiring 51. In the following, a line of a plurality of metal wires 5 connecting between components will be referred to as a connection portion.

The base plate 101 is housed in the case 1, the case 1 and the base plate 101 are joined by a resin adhesive or the like to form the case 1 with no lid and a bottom, and the base plate 101, the insulating substrate 3, the semiconductor element 104, the metal wirings 5 and 51 are covered with the insulating sealing material 4 and sealed by a resin by introducing the insulating sealing material 4 such as an epoxy resin into the opening on the upper surface side of the case 1. As the insulating sealing material 4, a silicon-based sealing material may be used.

Here, although a composite material, namely an AlSiC plate and a Cu plate, can be used for the base plate 101, the bottom surface of the case 1 may be formed of the insulating substrate 3 without providing the base plate 101 as long as the insulating performance and strength are sufficient when the semiconductor element 104 is used. That is, the lower conductor pattern 103e may be provided on the lower surface of the insulating substrate 3, and the lower conductor pattern 103e may be exposed as the bottom surface of the case 1.

As described above, if the number of metal wires 5 in the power module 100 increases, the wire interval becomes narrow, and it becomes difficult for air bubbles contained in the insulating sealing material 4 to escape from the gap between the metal wires 5.

< 1 st example of exhaust Structure >

Fig. 3 and 4 are diagrams illustrating the wiring arrangement of the wire connection portion having a vent structure for moving bubbles below the metal wiring 5 upward when the wiring interval is narrow, fig. 3 is a partial plan view of the power module 100 as viewed from above, and fig. 4 is a sagittal sectional view taken along line C-C in fig. 3.

Fig. 3 and 4 show a wire connection portion in which a diode 104b on an insulating substrate 3 and an upper conductor pattern 103b are wired by a plurality of metal wires 5 by wire bonding, and as shown in fig. 3, the arrangement interval of the metal wires 5 is about the line width of the metal wires 5. For example, when the line width of the metal wiring 5 is about 1mm and the arrangement interval of the metal wirings 5 is 1mm or less, the insulating sealing material 4 is filled in the case 1, and when the diameter of the air bubble in the insulating sealing material 4 is 1mm to 3mm, the air bubble cannot be discharged from between the metal wirings 5 and remains in the metal wirings 5. The accumulated air bubbles may be accumulated and have a further increased diameter.

However, as shown in fig. 4, the plurality of metal wirings 5 are looped (looping) in the same direction, and the wiring heights are different from each other, and the wiring heights are arranged so as to gradually increase or gradually decrease toward one direction of the queue. In fig. 4, the wiring height increases toward the left side facing the drawing. A structure in which the metal wiring 5 is disposed so that the wiring height changes as described above is defined as an exhaust structure.

Here, the mechanism of the exhaust structure will be described with reference to fig. 5. Fig. 5 shows an exhaust structure in which a plurality of metal wires 5 are looped in the same direction, facing the drawing, and the wire height is increased toward the right side, the plurality of metal wires 5 are bonded to a conductor MB by wire bonding, and air bubbles BB are present between the plurality of metal wires 5 looped and the conductor MB. The size of the air bubbles BB is larger than the arrangement interval of the metal wirings 5, and therefore cannot pass between the metal wirings 5. Further, the plurality of metal wirings 5 are covered with an insulating sealing material, together with the conductor MB, and the air bubbles BB are present in the insulating sealing material, but the insulating sealing material is omitted from illustration for convenience.

As shown in fig. 5, first, air bubbles BB located on the metal wiring 5 side having a low wiring height move to the metal wiring 5 side having a high wiring height with the passage of time as indicated by an arrow AR, and are finally discharged from under the metal wiring 5. The reason for this is that the specific gravity of the insulating sealing material, for example, 1.9 in the case of epoxy resin, and the specific gravity of the air bubbles BB, for example, 1 in the case of air, are different from each other in specific gravity, and the air bubbles BB move from a low position to a high position. The air bubbles BB discharged from under the metal wiring 5 move upward in a state where the insulating sealing material is in a liquid state before curing, and the viscosity of the insulating sealing material temporarily decreases during thermal curing, so that the air bubbles BB easily move upward. Therefore, the air bubbles in the insulating sealing material are gathered on the upper surface of the insulating sealing material 4 filled in the case 1, and are released (exhausted) from the insulating sealing material. This can reduce air bubbles in the insulating sealing material. In the past, it was difficult to exhaust the bubbles under the metal wiring 5, but by using the above-described exhaust structure, the bubbles under the metal wiring 5 were also easily exhausted. Therefore, the cured insulating sealing material can suppress the air bubbles from remaining as voids under the metal wiring 5, and can ensure the insulation of the power module 100.

< example 2 of exhaust gas Structure

Fig. 6 and 7 are diagrams illustrating a wiring arrangement having a gas exhaust structure for moving bubbles under the metal wiring 5 upward when the wiring interval is narrow, fig. 6 is a partial plan view of the power module 100 as viewed from above, and fig. 7 is a sagittal sectional view of the line C-C in fig. 6. The arrangement position, arrangement interval, and the like of the metal wiring 5 are the same as those in fig. 3 and 4.

In the exhaust structure shown in fig. 6, the wiring height of each of the plurality of metal wirings 5 is the lowest at the center portion of the wiring array, and the wiring height increases from the center portion toward the left direction (1 st direction) and the right direction (2 nd direction) in the drawing. Therefore, the air bubbles existing under the plurality of annular metal wirings 5 move toward at least one of the right side and the left side of the exhaust structure, and are exhausted from under the metal wirings 5, so that the air bubbles under the metal wirings 5 can be exhausted.

< example 3 of the exhaust gas Structure

Fig. 8 and 9 are diagrams illustrating a wiring arrangement having a gas exhaust structure for moving bubbles under the metal wiring 5 upward when the wiring interval is narrow, fig. 8 is a partial plan view of the power module 100 as viewed from above, and fig. 9 is a sagittal sectional view of the line C-C in fig. 8. The arrangement position of the metal wiring 5 is the same as that in fig. 3 and 4.

In the exhaust structure shown in fig. 9, the arrangement interval is wider at the center portion of the wiring array than at other portions, and the wiring height is reduced from the center portion toward the left direction (1 st direction) and the right direction (2 nd direction) in the drawing.

Therefore, bubbles existing under the plurality of annular metal wirings 5 move from at least one of the right and left sides of the exhaust structure toward the central portion, and are exhausted from under the metal wirings 5 in the gap of the central portion, so that the bubbles under the metal wirings 5 can be exhausted.

Considering that the diameter of the bubble is 1mm to 3mm, the gap at the center portion is set in the range of 1mm to 3 mm.

In the case where the arrangement interval can be made wider at the center portion of the wiring line than at other portions, as shown in fig. 10, the wiring height of each of the plurality of metal wirings 5 is the lowest at the center portion side of the wiring line, and the wiring height increases in the leftward direction (1 st direction) and the rightward direction (2 nd direction) in the drawing from the center portion side, contrary to the air-exhausting structure shown in fig. 9.

Thus, the air bubbles existing under the plurality of annular metal wirings 5 move toward at least one of the right side and the left side of the exhaust structure, and are exhausted from under the metal wirings 5, so that the air bubbles under the metal wirings 5 can be exhausted. Further, since the gap at the center of the wire array is wide, air bubbles existing under the metal wiring 5 near the center of the wire array may be discharged from the center, and the effect of exhausting air is improved.

< example 4 of the exhaust gas Structure

Fig. 11 and 12 are diagrams illustrating a lead arrangement having a vent structure for moving bubbles under the metal wiring 5 upward when the wiring interval is narrow, fig. 11 is a partial plan view of the power module 100 as viewed from above, and fig. 12 is a sagittal sectional view of the line C-C in fig. 11. The arrangement position of the metal wiring 5 is the same as that of fig. 3.

In the exhaust structure shown in fig. 11, the metal wirings 5 are arranged in the center portion of the wire array at intervals wider than other portions, and are inclined in the left direction (1 st direction) and the right direction (2 nd direction) with the center portion as a boundary. Therefore, as shown in fig. 12, the wiring height of each of the plurality of metal wirings 5 becomes lower toward the left and right directions in the drawing from the central portion, and the distal end side (upper side conductor pattern 103b) is wider than the proximal end side (diode 104b side) with respect to the central portion.

Therefore, bubbles existing under the plurality of metal wirings 5 in the ring shape are easily discharged from the central portion of the exhaust structure.

< example 5 of exhaust gas Structure

Fig. 13 is a diagram illustrating a lead arrangement having a gas discharge structure for moving bubbles under the metal wiring 5 upward when the wiring interval is narrow, and fig. 13 is a partial plan view of the power module 100 as viewed from above.

In the exhaust structure shown in fig. 13, the bonding positions of the adjacent metal wirings 5 are staggered and bonded so as to be different from each other. By performing the staggered bonding, even when the wiring interval is further narrowed, the insertion space of the bonding tool can be secured, and the bonding becomes easy.

In the case of performing such staggered bonding, similarly, for example, as shown in fig. 4, the plurality of metal wirings 5 are arranged so that the wiring heights thereof gradually increase or gradually decrease toward one direction of the row, whereby bubbles existing under the plurality of metal wirings 5 in the ring shape move toward the metal wirings 5 having a high wiring height and are exhausted.

In addition, as described above, when the wiring heights of the plurality of metal wirings 5 are changed in the case of performing the staggered bonding, the wiring lengths are changed, and thereby the inductance (resistance) is changed. Therefore, by making the wiring lengths uniform, the inductances can be unified, and the circuit design of the power module 100 can be simplified.

Fig. 14 is a plan view showing an exhaust structure in the case where the wiring lengths are made uniform in the case of performing the staggered bonding, and fig. 15 is a cross-sectional view corresponding to fig. 4.

As shown in fig. 14 and 15, the length of each of the plurality of metal wirings 5 in the plan view is set so that the wiring length of the metal wiring 5 having the lowest wiring height in the plan view is longest and the wiring length of the metal wiring 5 having the highest wiring height in the plan view is shortest. As a result, the entire length (actual wiring length) of each metal wiring 5 becomes the same, and the inductance can be unified.

As described above, the method of changing the wiring length in a plan view in accordance with the wiring height can be applied to examples 1 to 4 of the exhaust structure described above, and the circuit design of the power module 100 can be simplified by unifying the inductances.

< 6 th example of exhaust Structure

Fig. 16 and 17 are diagrams illustrating a lead arrangement having a vent structure for moving bubbles under the metal wiring 5 upward when the wiring interval is narrow, fig. 16 is a partial plan view of the power module 100 as viewed from above, and fig. 17 is a sagittal sectional view of the line C-C in fig. 16. The arrangement position of the metal wiring 5 is the same as that of fig. 3. In fig. 16 and 17, the upper metal wiring 5 is shown to be thick, but for convenience, the upper and lower metal wirings 5 are actually made to have the same thickness.

Fig. 16 and 17 show an exhaust structure in the case of a double wiring in which the metal wirings 5 are arranged to be overlapped in the loop forming direction, and in the case of such a double wiring, similarly, as shown in fig. 17, the wiring heights of the plurality of metal wirings 5 are arranged to be gradually higher or gradually lower toward one direction of the queue, whereby bubbles existing under the plurality of metal wirings 5 in the ring shape move toward the metal wiring 5 side having a high wiring height and are exhausted. Further, the exhaust structure is not limited to the above-described double wiring, and can be applied to a wiring such as a triple wiring that is further overlapped.

< example of application of exhaust Structure to other parts >

In the 1 st to 6 th examples of the above-described exhaust structure, the connection portion between the diode 104b and the upper conductor pattern 103b is described, but the exhaust structure may be applied to other connection portions.

Fig. 18 and 19 show a case 1 in which, for example, an air-bleeding structure is applied to a wire connection portion between an upper conductor pattern 103b and another upper conductor pattern 103C on an insulating substrate 3, fig. 18 is a partial plan view of a power module 100 as viewed from above, and fig. 19 is a sagittal cross-sectional view taken along line C-C in fig. 18, in which the wiring heights of a plurality of metal wirings 5 are arranged so as to gradually increase or gradually decrease in one direction toward a row. The upper conductor pattern 103c is present in a portion not shown in the plan view shown in fig. 2.

As shown in fig. 18 and 19, by applying the air-bleeding structure also when connecting the conductor patterns on the insulating substrate 3 to each other, air bubbles existing under the plurality of metal wirings 5 in the ring shape move toward the metal wirings 5 having a high wiring height and are bled.

Fig. 20 and 21 show a case of example 1 in which, for example, an air-bleeding structure is applied to the connection portion between the upper conductor pattern 103b and the main electrode terminal 2 on the insulating substrate 3, fig. 20 is a partial plan view of the power module 100 as viewed from above, and fig. 21 is a sagittal cross-sectional view taken along line C-C in fig. 20, and the wiring heights of the plurality of metal wirings 5 are arranged so as to gradually increase or gradually decrease toward one direction of the matrix.

As shown in fig. 20 and 21, by applying the air-bleeding structure also when the upper conductor pattern 103b on the insulating substrate 3 is connected to the main electrode terminal 2, air bubbles existing under the plurality of metal wirings 5 in the ring shape move toward the metal wirings 5 having a high wiring height and are bled.

Other constructions for exhaust gas

In embodiment 1 described above, for example, when the arrangement interval of the metal wirings 5 is 1mm or less and the diameter of the air bubbles in the insulating sealing material 4 is 1mm to 3mm, the air bubbles cannot be discharged from between the metal wirings 5, but the air discharge structure is obtained by making the interval of the metal wirings 5 larger than the diameter of the air bubbles.

However, when the line width of the metal wiring 5 is about 1mm, if the wiring interval is about 3mm, the increase in wiring density cannot be coped with along with the diversification of the rated value of the power module and the increase in current. Therefore, the wire width of the metal wire 5 is increased or a plate-like ribbon connector (ribbon bond) is used to increase the fusing current per 1 wire, and the wire interval is set to 1mm or more.

< embodiment 2 >

In the present embodiment, the power module according to embodiment 1 is applied to a power conversion device. Next, as embodiment 2, a case where embodiment 1 is applied to a three-phase inverter will be described.

Fig. 22 is a block diagram showing a configuration of a power conversion system to which the power conversion device according to the present embodiment is applied.

The power conversion system shown in fig. 22 includes a power supply 500, a power conversion device 600, and a load 700. The power supply 500 is a dc power supply and supplies dc power to the power conversion device 600. The power supply 500 may be configured by various power supplies, for example, a direct current system, a solar cell, a storage battery, or a rectifier circuit or an AC/DC converter connected to an alternating current system. The power supply 500 may be configured by a DC/DC converter that converts DC power output from the DC system into predetermined power.

Power conversion device 600 is a three-phase inverter connected between power supply 500 and load 700, and converts dc power supplied from power supply 500 into ac power to supply ac power to load 700. As shown in fig. 22, the power conversion device 600 includes: a main converter circuit 601 that converts dc power into ac power and outputs the ac power; and a control circuit 602 that outputs a control signal for controlling the main conversion circuit 601 to the main conversion circuit 601.

Load 700 is a three-phase motor driven by ac power supplied from power conversion device 600. The load 700 is not limited to a specific application, and is an electric motor mounted on various electric devices, for example, a motor for a hybrid car, an electric car, a railway vehicle, an elevator, or an air conditioner.

Hereinafter, the power conversion device 600 will be described in detail. The main converter circuit 601 includes a switching element and a flywheel diode (not shown), and is turned on and off by the switching element to convert dc power supplied from the power supply 500 into ac power and supply the ac power to the load 700. While various specific circuit configurations exist for the main converter circuit 601, the main converter circuit 601 according to the present embodiment is a two-level three-phase full bridge circuit and can be configured with 6 switching elements and 6 freewheeling diodes connected in anti-parallel with the respective switching elements. The power module 100 according to embodiment 1 described above is applied to a power module including the main converter circuit 601, and the plurality of metal wires 5 in the power module 100 are arranged in an exhaust structure. Two of the 6 switching elements are connected in series to form upper and lower arms, and each of the upper and lower arms forms each phase (U-phase, V-phase, W-phase) of the full bridge circuit. The load 700 is connected to 3 output terminals of the main converter circuit 601, which are output terminals of the upper and lower arms.

Further, the main conversion circuit 601 includes a drive circuit (not shown) for driving each switching element, but the drive circuit may be incorporated in the power module 100 as described in embodiment 1, or may be configured to have a separate drive circuit from the power module 100.

The drive circuit generates a drive signal for driving the switching element of the main conversion circuit 601 and supplies the drive signal to the control electrode of the switching element of the main conversion circuit 601. Specifically, a drive signal for turning the switching element on and a drive signal for turning the switching element off are output to the control electrode of each switching element in accordance with a control signal from a control circuit 602 described later. When the switching element is maintained in the on state, the drive signal is a voltage signal (on signal) greater than or equal to the threshold voltage of the switching element, and when the switching element is maintained in the off state, the drive signal is a voltage signal (off signal) less than the threshold voltage of the switching element.

The control circuit 602 controls the switching elements of the main conversion circuit 601 to supply desired power to the load 700. Specifically, the time (on time) at which each switching element of the main converter circuit 601 should be turned on is calculated based on the power to be supplied to the load 700. For example, the main conversion circuit 601 can be controlled by PWM control for modulating the on time of the switching element in accordance with the voltage to be output. Then, a control command (control signal) is output to a drive circuit provided in the main conversion circuit 601 so that an on signal is output to the switching element to be turned on at each time point and an off signal is output to the switching element to be turned off. The drive circuit outputs an on signal or an off signal as a drive signal to the control electrode of each switching element in accordance with the control signal.

By configuring the main converter circuit 601 with the power module 100 according to embodiment 1, it is possible to suppress air bubbles from remaining as voids under the metal wiring 5 in the cured insulating sealing material, and it is possible to avoid problems in the power module having ensured insulation properties and in the power converter including the power module, and to suppress functional deterioration thereof.

In the present embodiment, an example in which the present invention is applied to a two-level three-phase inverter has been described, but the present invention is not limited to this, and can be applied to various power conversion devices. In the present embodiment, a two-level power conversion device is used, but a three-level or multi-level power conversion device may be used, and the present invention may be applied to a single-phase inverter when power is supplied to a single-phase load. In addition, the present invention can be applied to a DC/DC converter or an AC/DC converter even when power is supplied to a DC load or the like.

The power converter of the present embodiment is not limited to the case where the load is a motor, and may be used as a power supply device for an electric discharge machine, a laser machine, an induction heating cooker, or a non-contactor power supply system, and may also be used as a power conditioner for a solar power generation system, a power storage system, or the like.

In addition, the present invention can be modified and omitted as appropriate within the scope of the present invention.