JP2023173556A - Method for manufacturing semiconductor module, method for manufacturing power conversion system, semiconductor module, power conversion system - Google Patents

Abstract

To suppress the occurrence of shrinkage nests in semiconductor modules by the technology disclosed in this application specification.SOLUTION: A method for manufacturing a semiconductor module relating to the technology disclosed in this application specification is to bond a semiconductor element to the top surface of an insulating substrate, the insulating substrate to which the semiconductor device is bonded is bonded to the base portion via a first solder, the joining of the insulating substrate and the base portion is performed by cooling the first solder while bringing the heated first solder into contact with the insulating substrate and the base portion and applying vibration to the first solder after the temperature of the first solder begins to drop.SELECTED DRAWING: Figure 3

Description

The technology disclosed in this specification relates to a semiconductor module.

Power modules are becoming widespread in all kinds of products such as industrial equipment, home appliances, and information terminals. Power modules installed in electric vehicles or industrial equipment that handle large currents and high voltages are required to have high heat dissipation properties (for example, patent (See Reference 1).

In a power module, when shrinkage cavities (solidification cracks) occur in the solder joint between the fin base and the ceramic substrate due to solidification and shrinkage of the solder, they impede heat conduction and reduce heat dissipation.

In addition, power modules are also required to have a package form that can be applied to SiC semiconductors, which are likely to become mainstream in the future due to their high operating temperature and excellent efficiency.

Patent No. 6008750

Semiconductor modules such as power modules are becoming popular in all situations such as electric energy generation, power transmission, and regeneration as awareness of environmental issues increases.

Since semiconductor modules handle large currents and high voltages, ceramic substrates with high insulation and heat dissipation properties are used as insulating substrates. In addition, a method may be used in which a ceramic substrate is soldered to a fin base made of aluminum or copper, which has excellent heat conduction, to ensure a heat dissipation path.

A ceramic board on which multiple large semiconductor elements are mounted is a large board with a side of, for example, 30 mm or more and 70 mm or less, and when this is soldered to a fin base, shrinkage cavities occur due to solidification and shrinkage of the solder. (solidification cracking) may occur. There is a concern that this shrinkage cavity may become an unbonded portion, inhibit heat conduction, and reduce heat dissipation.

The technology disclosed in this specification has been developed in view of the problems described above, and is a technology for suppressing the occurrence of shrinkage cavities in semiconductor modules.

A method for manufacturing a semiconductor module, which is a first aspect of the technology disclosed in the present specification, includes bonding a semiconductor element to an upper surface of an insulating substrate, and bonding the insulating substrate to which the semiconductor element has been bonded to a first solder. The first solder is bonded to the base portion through the insulating substrate and the base portion is bonded to the insulating substrate, and the temperature begins to decrease while the heated first solder is in contact with the insulating substrate and the base portion. The first solder is cooled while applying vibration to the first solder.

According to at least the first aspect of the technology disclosed in the present specification, overcooling is less likely to occur during the solder solidification process. Therefore, it is possible to suppress the occurrence of shrinkage cavities.

In addition, objects, features, aspects, and advantages related to the technology disclosed herein will become more apparent from the detailed description and accompanying drawings set forth below.

FIG. 2 is a cross-sectional view schematically showing an example of a manufacturing process of a power module as a semiconductor module according to an embodiment. FIG. 2 is a cross-sectional view schematically showing an example of a manufacturing process of a power module as a semiconductor module according to an embodiment. FIG. 2 is a cross-sectional view schematically showing an example of a manufacturing process of a power module as a semiconductor module according to an embodiment. FIG. 2 is a cross-sectional view schematically showing an example of a manufacturing process of a power module as a semiconductor module according to an embodiment. FIG. 2 is a plan view showing an example of the configuration of a power module according to an embodiment. It is a figure showing an example of application of the power module concerning an embodiment. It is a figure which shows the other example of application of the power module regarding embodiment. It is a figure which shows another example of the manufacturing process of a power module regarding embodiment. FIG. 2 is a cross-sectional view schematically showing an example of a manufacturing process of a power module as a semiconductor module according to an embodiment. 1 is a cross-sectional view schematically showing an example of the configuration of a power module as a semiconductor module according to an embodiment. 1 is a cross-sectional view schematically showing an example of the configuration of a power module according to an embodiment. FIG. 3 is a cross-sectional view schematically showing another example of the configuration of the power module according to the embodiment. 1 is a diagram conceptually showing an example of a configuration of a power conversion system including a power conversion device according to an embodiment.

Embodiments will be described below with reference to the accompanying drawings. In the following embodiments, detailed features and the like are shown for technical explanation, but these are merely examples, and not all of them are necessarily essential features for the embodiments to be implemented.

Note that the drawings are schematically illustrated, and for convenience of explanation, structures may be omitted or simplified as appropriate in the drawings. Further, the mutual relationship between the sizes and positions of the structures shown in different drawings is not necessarily described accurately and may be changed as appropriate. Further, even in drawings such as plan views that are not cross-sectional views, hatching may be added to facilitate understanding of the content of the embodiments.

In addition, in the following description, similar components are shown with the same reference numerals, and their names and functions are also the same. Therefore, detailed descriptions thereof may be omitted to avoid duplication.

In addition, in the description provided in the specification of this application, when a component is described as "comprising," "includes," or "has," unless otherwise specified, exclusions that exclude the presence of other components are also used. It's not an expression.

Furthermore, even if ordinal numbers such as "first" or "second" are sometimes used in the description of the present specification, these terms will not be used to facilitate understanding of the content of the embodiments. These ordinal numbers are used for convenience and the content of the embodiments is not limited to the order that can occur based on these ordinal numbers.

In addition, in the description provided herein, specific positions or directions such as "top", "bottom", "left", "right", "side", "bottom", "front" or "back" Even if terms that mean It is independent of the position or direction of the

In addition, in the description provided in the specification of this application, when "...upper surface" or "...lower surface" etc. are described, in addition to the upper surface itself or the lower surface itself of the target component, This also includes a state in which other components are formed on the upper or lower surface of the. That is, for example, when it is described as "B provided on the upper surface of A", it does not prevent another component "C" from being interposed between A and B.

<First embodiment>
A semiconductor module and a method for manufacturing the semiconductor module according to this embodiment will be described below. Furthermore, in the following description, the expression "A and B are electrically connected" means that current can flow bidirectionally between configuration A and configuration B.

<About the configuration of the semiconductor module>
1 to 4 are cross-sectional views schematically showing an example of a manufacturing process of a power module as a semiconductor module according to this embodiment.

As an example is shown in FIG. 1, a semiconductor element 2 is positioned and mounted on a ceramic substrate 10 together with a solder 31. Then, in a reflow oven, preheating is performed at 150° C. for 90 seconds and main heating is performed at 250° C. for 30 seconds to perform soldering. Here, the solder 31 for mounting the semiconductor element 2 is in the form of a sheet, for example, has a thickness of 0.3 mm, is made of 96.5% tin, 3% silver, and 0.5% copper, and has a melting point. The temperature is 217°C.

The semiconductor element 2 is, for example, a silicon diode. In this case, the dimensions are, for example, 13 mm long, 10 mm wide, and 0.2 mm thick. Alternatively, the semiconductor element 2 is, for example, an insulated gate bipolar transistor (IGBT) made of silicon. In this case, the dimensions are, for example, 13 mm long, 13 mm wide, and 0.2 mm thick.

In the ceramic substrate 10, a copper surface conductor layer 12 is formed on the upper surface of an aluminum nitride base material 11 by brazing. Further, a back conductor layer 13 is formed on the lower surface of the aluminum nitride base material 11 by brazing. Here, the aluminum nitride base material 11 has a thickness of, for example, 0.64 mm. Further, the front conductor layer 12 and the back conductor layer 13 have a thickness of, for example, 0.8 mm.

Next, as an example is shown in FIG. 2, the base plate 70 and the ceramic substrate 10 on which the semiconductor element 2 is mounted are placed on top of each other with the solder 30 interposed therebetween. Further, a silicone adhesive 81 is applied around the base plate 70, and the case 5 in which the external electrodes 61 and the signal electrodes 63 are inserted and formed is overlapped with the silicone adhesive 81 interposed therebetween. External electrode 61 is bonded to surface conductor layer 12 via solder 32. Here, the base plate 70 is made of copper, for example, and has dimensions of 60 mm in length, 45 mm in width, and 3 mm in thickness. Further, the solder 30 for stacking the ceramic substrate 10 on which the semiconductor element 2 is mounted on the base plate 70 is in the form of a sheet, and has a thickness of 0.4 mm, for example, and is made of 96.5% tin and 3% silver. %, copper 0.5%, and the melting point is 217°C. Further, the case 5 is made of, for example, polyphenylene sulfide (PPS) resin, and has dimensions of 60 mm in length, 45 mm in width, and 6 mm in thickness.

Next, as shown in an example in FIG. 3, the ceramic substrate 10 and the base plate 70 are heated in a reflow oven with preheating at 150°C for 90 seconds and main heating at 250°C for 30 seconds. Melt the solder 30. After that, after cooling has started and the temperature of the solder 30 has begun to fall, the ultrasonic horn 91 is inserted into the opening of the hot plate 90 (cooling plate) in the reflow oven and applied to the back surface of the base plate 70 (lower surface ) and apply 44 kHz ultrasonic waves. As a result, vibration can be applied to the solder 30 that is being cooled. In this step, the silicone adhesive 81 is also cured by heating, and the case 5 and the base plate 70 are bonded together.

Next, as an example is shown in FIG. 4, the main terminal of the diode and the main terminal of the IGBT, which are the semiconductor elements 2, are connected to the surface conductor layer 12 of the ceramic substrate 10 or the external electrode 61 by an aluminum wire 41. The gate electrode of the IGBT is connected to the signal electrode 63 by an aluminum wire 42. Here, the wire 41 has a diameter of 0.4 mm, for example. Further, the wire 42 has a diameter of 0.15 mm, for example. Then, the inside of the case 5 is filled with the sealing resin 82, thereby forming a power module. Here, the sealing resin 82 is, for example, an epoxy resin in which silica filler is dispersed.

Here, the aluminum nitride base material 11 was used as the base material of the ceramic substrate 10, but a silicon nitride or alumina base material may also be used. In addition, copper was used for the front conductor layer 12 and the back conductor layer 13, but even aluminum conductor layers can be used by modifying the surface with nickel plating or the like so that it can be soldered. be able to. Further, a resin insulated metal substrate or a glass epoxy resin substrate may be used instead of the ceramic substrate 10 as long as the required heat dissipation performance is satisfied.

Further, although copper is used as the material for the base plate 70, the base plate may be made of aluminum or an aluminum alloy. Further, although the diode and IGBT as the semiconductor element 2 are made of silicon, a wide bandgap semiconductor such as silicon carbide or gallium nitride may be used.

As for the solder 30 and the solder 31, those containing 96.5% tin, 3% silver, and 0.5% copper and having a melting point of 217°C were used, but the solder 30 and 31 were 99.3% tin and 0.5% copper. A solder material containing 7% tin and a melting point of 224° C., or a solder material containing 95% tin and 5% antimony and a melting point of 240° C. may be used. Further, a part of the solder may be replaced with a bonding material other than solder, such as a silver epoxy adhesive, a silver sintered material, or a brazing material.

Further, although wires 41 and 42 are made of aluminum, they may be made of aluminum alloy containing a small amount of additives such as iron, or may be made of copper.

Further, although the case 5 is made of PPS, it can be replaced with a case made of liquid crystal polymer (LCP) to improve heat resistance.

Further, although a copper frame was used for the external electrode 61 and the signal electrode 63, the external electrode 61 and the signal electrode 63 may be appropriately nickel-plated or replaced with a copper alloy or nickel-plated aluminum frame. You can also

Further, although an epoxy resin in which silica filler is dispersed is used as the sealing resin 82, a filler such as alumina may be used, and the same effect can be obtained by mixing an epoxy resin with a silicone resin. A similar effect can also be obtained by sealing with only silicone resin.

Furthermore, in the above description, ultrasonic waves are applied from the ultrasonic horn 91 when the solder 30 is being cooled after heating is completed (after the temperature of the solder 30 has started to decrease), but when vibrations are being applied, Since the bonding state between the ceramic substrate 10 and the base plate 70 becomes unstable, the cooling rate may be reduced and productivity may be affected. Therefore, by applying ultrasonic waves after the temperature of the solder 30 decreases after cooling starts and the temperature of the solder 30 falls below the melting point (liquidus temperature) of 217°C, the time required for cooling can be shortened. , productivity can be improved.

Further, the solder 31 for joining the semiconductor element 2 to the ceramic substrate 10 is a solder having a higher melting point than the solder 30 used for joining the base plate 70, and the temperature of the solder 30 being cooled is higher than the melting point of the solder 31. Ultrasonic waves can also be applied after the temperature has decreased. By doing so, vibrations are applied to the solder 30 while the bond between the semiconductor element 2 and the ceramic substrate 10 by the solder 31 is fixed, which may cause misalignment of the semiconductor element 2 with respect to the ceramic substrate 10. It becomes possible to suppress the In this case, the solder 30 is made of, for example, 96.5% tin, 3% silver, and 0.5% copper, and has a melting point of 217°C, and the solder 31 is made, for example, of 95% tin, 5% antimony, and has a melting point of 217°C. can be 240°C.

FIG. 5 is a plan view showing an example of the configuration of a power module according to this embodiment. Note that in FIG. 5, illustration of the sealing resin is omitted.

As an example is shown in FIG. 5, the surface conductor layer 12 of the ceramic substrate 10 is patterned to function as a 2-in-1 module. Further, the semiconductor element 2 mounted on the upper surface of the ceramic substrate 10 has a main circuit formed by wires 41 and is connected to an external electrode 61. The gate electrode 20g and the like in the semiconductor element 2 are connected to the signal electrode 63 by a wire 42 to form a control circuit. Note that although a 2-in-1 module is shown as an example in FIG. 5, a 1-in-1 module or a 6-in-1 module may be used.

FIG. 6 is a diagram showing an example of application of the power module according to this embodiment. In the example shown in FIG. 6, cooling fins 71 are attached to the lower surface of the base plate 70 with thermally conductive grease 83 interposed therebetween. The cooling fins 71 ensure a heat dissipation path for the semiconductor element 2 .

FIG. 7 is a diagram showing another example of application of the power module according to this embodiment. In the example shown in FIG. 7, a base plate 70p with pin fins 72 is bonded to case 5 via silicone adhesive 81 and bonded to the lower surface of ceramic substrate 10 via solder 30. The pin fin 72 is provided on the lower surface side of the base plate 70p. A water cooling jacket 73 is further fastened to the base plate 70p. The base plate 70p and the water cooling jacket 73 enable heat dissipation by water cooling.

FIG. 8 is a diagram showing another example of the power module manufacturing process according to this embodiment. As an example shown in FIG. 8, the ceramic substrate 10 can also be vibrated by applying (bringing into contact with) the top surface of the semiconductor element 2 with the ultrasonic horn 91. As a result, vibration can be applied to the solder 30. Alternatively, an ultrasonic horn 91 may be incorporated into the hot plate 90 to vibrate the hot plate 90 itself.

<Second embodiment>
A semiconductor module and a method for manufacturing the semiconductor module according to this embodiment will be described. In addition, in the following description, components similar to those described in the embodiment described above will be illustrated with the same reference numerals, and detailed description thereof will be omitted as appropriate. .

<About the configuration of the semiconductor module>
FIG. 9 is a cross-sectional view schematically showing an example of a manufacturing process of a power module as a semiconductor module according to this embodiment. In FIG. 9, the process of applying ultrasonic waves is particularly shown.

As an example is shown in FIG. 9, in the process in which a base plate 70 and a ceramic substrate 10 on which a semiconductor element 2 is mounted are bonded via solder 30, a reflow oven is used instead of a hot plate method. It is a wind system, and the mechanism that transports the power modules is a conveyor.

In this case, at least a portion of the conveyor roller 92 in the conveyor is an eccentric roller whose rotation center is offset from the center of the roller (eccentric). The eccentric roller vibrates during rotation due to the above-mentioned deviation.

Since at least a portion of the conveyor roller 92 is an eccentric roller, vibrations also occur in the power module when the conveyed power module passes over the eccentric roller. The above-mentioned vibrations in the power module can reduce overcooling of the solder 30 when the heated solder 30 is being cooled (for example, the state shown in FIG. 3).

The eccentric conveyor roller 92 may be provided only in the area where the solder 30 is cooled. Further, the solder 31 for joining the semiconductor element 2 to the ceramic substrate 10 is a solder having a higher melting point than the solder 30 used for joining to the base plate 70, and after the temperature of the solder 30 becomes lower than the melting point of the solder 31, By controlling the conveyance timing so that the power module enters the area where the conveyor roller 92 is arranged, it is possible to suppress the occurrence of positional shift of the semiconductor element 2 with respect to the ceramic substrate 10. In this case, the solder 30 is made of, for example, 96.5% tin, 3% silver, and 0.5% copper, and has a melting point of 217°C, and the solder 31 is made, for example, of 95% tin, 5% antimony, and has a melting point of 217°C. can be 240°C.

<Third embodiment>
A semiconductor module and a method for manufacturing the semiconductor module according to this embodiment will be described. In addition, in the following description, components similar to those described in the embodiment described above will be illustrated with the same reference numerals, and detailed description thereof will be omitted as appropriate. .

<About the configuration of the semiconductor module>
FIG. 10 is a cross-sectional view schematically showing an example of the configuration of a power module as a semiconductor module according to this embodiment.

As an example is shown in FIG. 10, a base plate 70 and a ceramic substrate 10 on which a semiconductor element 2 is mounted are soldered together via a solder 30. Here, the base plate 70 is made of copper, for example, and has dimensions of 60 mm in length, 45 mm in width, and 3 mm in thickness. Further, the solder 30 is in the form of a sheet, and has a thickness of, for example, 0.4 mm.

A silicone adhesive 81 is applied around the ceramic substrate 10, and the ceramic substrate 10 is bonded via the silicone adhesive 81 to a copper lead frame on which an external electrode 61f or a signal electrode 63f is formed.

The main terminals of the diode and the IGBT as the semiconductor element 2 are connected to the surface conductor layer 12 of the ceramic substrate 10 or the external electrode 61f of the lead frame by an aluminum wire 41. Here, the wire 41 has a diameter of 0.4 mm, for example.

Further, the gate electrode of the IGBT and the signal electrode 63f of the lead frame are wire-bonded using an aluminum wire 42 to form a circuit. Here, the wire 42 has a diameter of 0.15 mm, for example.

Then, the transfer mold resin 84 insulates and seals the power module while exposing one end of the external electrode 61f, one end of the signal electrode 63f, and the back surface of the base plate 70.

FIG. 11 is a cross-sectional view schematically showing an example of the configuration of a power module according to this embodiment. FIG. 11 shows a process in which the ceramic substrate 10 and the base plate 70 having the configuration shown in FIG. 10 are soldered together.

The base plate 70 is housed in a recess 90a formed in a hot plate 90 of a reflow oven, with the copper lead frame and the ceramic substrate 10 bonded together with a silicone adhesive 81. Then, in a reflow oven, the solder 30 is melted by preheating at 150° C. for 90 seconds and main heating at 250° C. for 30 seconds. Thereafter, after starting cooling, the ultrasonic horn 91 is brought into contact with the back surface of the hot plate 90 (cooling plate) in the reflow oven and applied to the back surface of the base plate 70 to apply 44 kHz ultrasonic waves. In this step, the silicone adhesive 81 is also cured by heating, and the lead frame (external electrode 61f and signal electrode 63f) and ceramic substrate 10 are bonded together.

FIG. 12 is a cross-sectional view schematically showing another example of the configuration of the power module according to this embodiment. In the example shown in FIG. 12, cooling fins 71 are attached to the lower surface of the base plate 70 with thermally conductive grease 83 interposed therebetween. The cooling fins 71 ensure a heat dissipation path for the semiconductor element 2 .

Note that in this embodiment, a lead frame made of copper is used, but a lead frame made of alloy or nickel-plated aluminum may also be used.

<Fourth embodiment>
A power conversion device and a method for manufacturing the power conversion device according to the present embodiment will be described. In the following description, the same components as those described in the embodiments described above will be illustrated with the same reference numerals, and detailed description thereof will be omitted as appropriate.

<About the configuration of the power converter>
In this embodiment, the power module related to the embodiment described above is applied to a power conversion device. Although the power conversion device to which the present invention is applied is not limited to a specific application, a case where the present invention is applied to a three-phase inverter will be described below.

FIG. 13 is a diagram conceptually showing an example of the configuration of a power conversion system including the power conversion device of this embodiment.

As an example shown in FIG. 13, the power conversion system includes a power source 2100, a power conversion device 2200, and a load 2300. Power supply 2100 is a DC power supply and supplies DC power to power conversion device 2200. The power source 2100 can be configured with various things, such as a DC system, a solar battery, or a storage battery. Further, the power supply 2100 can be configured with a rectifier circuit or an AC-DC converter connected to an AC system. Further, the power supply 2100 can also be configured with a DC-DC converter that converts DC power output from a DC system into predetermined power.

Power conversion device 2200 is a three-phase inverter connected between power supply 2100 and load 2300. Power conversion device 2200 converts DC power supplied from power supply 2100 into AC power, and further supplies the AC power to load 2300.

The power conversion device 2200 also includes a conversion circuit 2201 that converts DC power into AC power and outputs the converted power, and outputs a control signal for controlling the conversion circuit 2201 to the conversion circuit 2201, as shown in an example in FIG. A control circuit 2203 is provided.

Load 2300 is a three-phase electric motor driven by AC power supplied from power converter 2200. Note that the load 2300 is not limited to a specific use, but is a motor installed in various electrical devices, such as a motor used in a hybrid vehicle, electric vehicle, railway vehicle, elevator, or air conditioner. It is.

The details of the power conversion device 2200 will be described below. The conversion circuit 2201 includes a switching element and a free wheel diode (not shown here). Then, the switching element performs a switching operation to convert the DC power supplied from the power supply 2100 into AC power, and further supplies the AC power to the load 2300.

Although there are various specific circuit configurations of the conversion circuit 2201, the conversion circuit 2201 according to this embodiment is a two-level, three-phase full bridge circuit, and has six switching elements and each switching element. It is equipped with six freewheeling diodes connected in antiparallel.

The power module in any of the embodiments described above is applied to at least one of each switching element and each free wheel diode in conversion circuit 2201. The six switching elements are connected in series every two switching elements to constitute an upper and lower arm, and each upper and lower arm constitutes each phase (that is, U phase, V phase, and W phase) of the full bridge circuit. The output terminals of the respective upper and lower arms (that is, the three output terminals of the conversion circuit 2201) are connected to the load 2300.

Further, the conversion circuit 2201 includes a drive circuit (not shown here) that drives each switching element, but the drive circuit may be built in a power module that is a semiconductor module, or the drive circuit may be built in a power module that is a semiconductor module, or The configuration may be provided separately from the module. The drive circuit generates a drive signal for driving the switching element of the conversion circuit 2201, and further supplies the drive signal to the control electrode of the switching element of the conversion circuit 2201. Specifically, based on a control signal output from a control circuit 2203 (described later), a drive signal that turns the switching element on and a drive signal that turns the switching element off are output to the control electrodes of each switching element. do.

When keeping the switching element in the on state, the drive signal is a voltage signal that is greater than or equal to the threshold voltage of the switching element (i.e., an on signal), and when keeping the switching element in the off state, the drive signal is less than or equal to the threshold voltage of the switching element. voltage signal (ie, off signal).

Control circuit 2203 controls switching elements of conversion circuit 2201 so that desired power is supplied to load 2300. Specifically, based on the power to be supplied to the load 2300, the time during which each switching element of the conversion circuit 2201 should be in the on state (ie, on time) is calculated. For example, the conversion circuit 2201 can be controlled by PWM control that modulates the on-time of the switching element according to the voltage to be output.

The control circuit 2203 then sends a control command (i.e., , control signal). The drive circuit outputs an on signal or an off signal as a drive signal to the control electrode of each switching element based on the control signal.

In the power conversion device 2200 according to this embodiment, the power module according to any of the embodiments described above is applied as the switching element of the conversion circuit 2201, so that it is possible to stabilize the on-resistance after passing through the energization cycle. can.

Note that in this embodiment, an example has been described in which the power module in any of the embodiments described above is applied to a two-level three-phase inverter, but the application example is not limited to this. The power module in any of the embodiments described above can be applied to various power converters.

Further, in this embodiment, a two-level power conversion device has been described, but the power module in any of the embodiments described above may be applied to a three-level or multi-level power conversion device. . Furthermore, when power is supplied to a single-phase load, the power module in any of the embodiments described above may be applied to a single-phase inverter.

Further, when power is supplied to a DC load or the like, the power module in any of the embodiments described above can be applied to a DC-DC converter or an AC-DC converter.

Furthermore, the power conversion device to which the power module in any of the embodiments described above is applied is not limited to the case where the above-mentioned load is an electric motor, but includes, for example, an electrical discharge machine, a laser processing machine, etc. It can also be used as a power supply device for a machine, an induction heating cooker, or a non-contact power supply system. Further, a power conversion device to which the power module in any of the embodiments described above is applied can also be used as a power conditioner in a solar power generation system, a power storage system, or the like.

<About the manufacturing method of the power conversion device>
Next, a method for manufacturing a power conversion device according to this embodiment will be explained.

First, a power module is manufactured using the manufacturing method described in the embodiment described above. Then, a conversion circuit 2201 having the power module is provided as a configuration of a power conversion device. The conversion circuit 2201 is a circuit for converting input power and outputting the converted power.

A control circuit 2203 is provided as a configuration of the power conversion device. The control circuit 2203 is a circuit for outputting a control signal for controlling the conversion circuit 2201 to the conversion circuit 2201.

The semiconductor switching element used in the embodiments described above is not limited to a switching element made of a silicon (Si) semiconductor. For example, the semiconductor switching element may be a non-Si semiconductor having a wider bandgap than a Si semiconductor. It may be made of material.

Examples of wide bandgap semiconductors that are non-Si semiconductor materials include silicon carbide, gallium nitride-based materials, and diamond.

Switching elements made of wide bandgap semiconductors can be used even in high voltage regions where unipolar operation is difficult with Si semiconductors, and can greatly reduce switching losses that occur during switching operations. Therefore, it is possible to greatly reduce power loss.

Furthermore, switching elements made of wide bandgap semiconductors have low power loss and high heat resistance. Therefore, when configuring a power module including a cooling section, it is possible to reduce the size of the radiation fins of the heat sink, thereby making it possible to further reduce the size of the semiconductor module.

Furthermore, switching elements made of wide bandgap semiconductors are suitable for high frequency switching operations. Therefore, when applied to a converter circuit that requires high frequency, the reactor or capacitor connected to the converter circuit can be downsized by increasing the switching frequency.

Therefore, similar effects can be obtained even when the semiconductor switching element in the embodiment described above is a switching element made of a wide gap semiconductor such as silicon carbide.

<About the effects produced by the embodiments described above>
Next, examples of effects produced by the embodiment described above will be shown. In addition, in the following description, the effects will be described based on the specific configurations shown in the embodiments described above, but examples will not be included in the present specification to the extent that similar effects are produced. may be replaced with other specific configurations shown. That is, for convenience, only one of the concrete configurations that are associated may be described below as a representative, but other specific configurations that are described as a representative may also be described. It may be replaced with a similar configuration.

Further, the replacement may be made across multiple embodiments. That is, the respective configurations shown as examples in different embodiments may be combined to produce similar effects.

According to the embodiment described above, in the method for manufacturing a semiconductor module, the semiconductor element 2 is bonded to the upper surface of the insulating substrate. Here, the insulating substrate corresponds to, for example, the ceramic substrate 10. Then, the ceramic substrate 10 to which the semiconductor element 2 is bonded is bonded to the base portion via the first solder. Here, the first solder corresponds to, for example, the solder 30. Further, the base portion corresponds to, for example, the base plate 70. Here, the joining between the ceramic substrate 10 and the base plate 70 is carried out with the heated solder 30 in contact with the ceramic substrate 10 and the base plate 70, while applying vibration to the solder 30 after the temperature has started to decrease. This is to cool the solder 30.

According to such a configuration, overcooling is less likely to occur during the solidification process of the solder 30. Therefore, it is possible to suppress the occurrence of large shrinkage cavities due to concentration of solidification shrinkage due to the solder 30 solidifying all at once.

Note that if there are no particular restrictions, the order in which each process is performed can be changed.

In addition, if other configurations exemplified in the specification of the present application are appropriately added to the above configuration, that is, if other configurations in the specification of the present application that are not mentioned as the above configurations are appropriately added. Even if there is, the same effect can be produced.

Further, according to the embodiment described above, the ceramic substrate 10 and the base plate 70 are conveyed by the conveyor roller 92 while being in contact with the heated solder 30, respectively. Here, the conveyor roller 92 includes an eccentric roller whose rotation center is shifted. Then, the solder 30 is cooled while the ceramic substrate 10 and the base plate 70 are being conveyed by the conveyor roller 92, and the solder 30 after the temperature starts to decrease is connected to the ceramic substrate 10 and the base plate 70. The purpose is to apply vibrations generated by the eccentric roller to the solder 30 when the solder 30 is conveyed by the eccentric roller. According to such a configuration, when the solder 30 being transported is being cooled, overcooling of the solder 30 can be reduced.

Further, according to the embodiment described above, the joining between the ceramic substrate 10 and the base plate 70 is achieved by using an ultrasonic horn that contacts the solder 30 from the lower surface of the base plate 70 after the temperature has started to decrease. The purpose is to cool the solder 30 while applying the vibration generated by the solder 30. According to such a configuration, the degree of freedom in the method of applying vibration to the solder 30 using the ultrasonic horn 91 increases.

Further, according to the embodiment described above, the joining between the ceramic substrate 10 and the base plate 70 is achieved by using an ultrasonic horn that contacts the solder 30 from the upper surface of the semiconductor element 2 after the temperature has started to decrease. The purpose is to cool the solder 30 while applying the vibration generated by the solder 30. According to such a configuration, the degree of freedom in the method of applying vibration to the solder 30 using the ultrasonic horn 91 increases.

Further, according to the embodiment described above, the joining between the ceramic substrate 10 and the base plate 70 is performed by cooling the solder 30 while the heated solder 30 is in contact with the ceramic substrate 10 and the base plate 70. Then, after the temperature of the solder 30 falls below the liquidus temperature (melting point), vibration is applied to the solder 30. According to such a configuration, by shortening the time for which vibration is applied, the accuracy of bonding between the ceramic substrate 10 and the base plate 70 is increased, and the productivity of the semiconductor module is improved and the positional shift of the semiconductor element 2 is suppressed. can be realized.

Further, according to the embodiment described above, the semiconductor element 2 is bonded to the upper surface of the ceramic substrate 10 via the second solder. Here, the second solder corresponds to, for example, the solder 31. The melting point of the solder 31 is higher than that of the solder 30. According to such a configuration, vibration is applied to the solder 30 while the bond between the semiconductor element 2 and the ceramic substrate 10 by the solder 31 is fixed, so that the position of the semiconductor element 2 with respect to the ceramic substrate 10 is changed. It is possible to suppress the occurrence of misalignment.

Further, according to the embodiment described above, the joining between the ceramic substrate 10 and the base plate 70 is performed by cooling the solder 30 while the heated solder 30 is in contact with the ceramic substrate 10 and the base plate 70. Then, after the temperature of the solder 30 reaches a temperature lower than the melting point of the solder 31, vibration is applied to the solder 30. According to such a configuration, vibration is applied to the solder 30 while the bond between the semiconductor element 2 and the ceramic substrate 10 by the solder 31 is fixed, so that the position of the semiconductor element 2 with respect to the ceramic substrate 10 is changed. It is possible to suppress the occurrence of misalignment.

Further, according to the embodiment described above, the base plate 70 has a fin structure on the surface opposite to the surface joined to the ceramic substrate 10. Here, the fin structure corresponds to at least one of the cooling fins 71, pin fins 72, etc., for example. According to such a configuration, a heat dissipation path for the semiconductor element 2 can be appropriately secured by the fin structure.

Further, according to the embodiment described above, in a method for manufacturing a power conversion device, a conversion circuit that includes a semiconductor module manufactured by the above manufacturing method and that converts input power and outputs the converted power is provided. 2201 is provided. A control circuit 2203 is provided that outputs a control signal for controlling the conversion circuit 2201 to the conversion circuit 2201. According to such a configuration, overcooling is less likely to occur in the process in which the temperature of the solder 30 decreases. Therefore, it is possible to suppress the occurrence of large shrinkage cavities due to concentration of solidification shrinkage due to the solder 30 solidifying all at once.

<About modifications of the embodiment described above>
In the embodiments described above, the materials, materials, dimensions, shapes, relative arrangement relationships, implementation conditions, etc. of each component may also be described, but these are only one example in all aspects. However, it is not limited.

Accordingly, countless variations and equivalents, not illustrated, are envisioned within the scope of the technology disclosed herein. For example, when at least one component is modified, added, or omitted, or when at least one component in at least one embodiment is extracted and combined with a component in another embodiment. shall be included.

In addition, in the embodiments described above, if a material name is stated without being specified, unless a contradiction occurs, the material may contain other additives, such as an alloy. shall be included.

Further, the description herein is incorporated by reference for all purposes related to the present technology, and is not admitted to be prior art.

Hereinafter, various aspects of the present disclosure will be collectively described as supplementary notes.

(Additional note 1)
A semiconductor element is bonded to the top surface of an insulating substrate,
the insulating substrate to which the semiconductor element is bonded is bonded to a base portion via a first solder;
The bonding between the insulating substrate and the base portion is performed by applying vibration to the first solder after the temperature starts to decrease while the heated first solder is in contact with the insulating substrate and the base portion. cooling the first solder while giving
A method for manufacturing semiconductor modules.

(Additional note 2)
A method for manufacturing a semiconductor module according to Supplementary Note 1,
The insulating substrate and the base portion are conveyed by a conveyor roller while being in contact with the heated first solder,
The conveyor roller includes an eccentric roller whose rotation center is shifted,
The first solder is cooled while the insulating substrate and the base are being conveyed by the conveyor roller, and the first solder is bonded to the insulating substrate and the base after the temperature starts to decrease. applying vibrations generated by the eccentric roller to the first solder when the first solder is conveyed by the eccentric roller;
A method for manufacturing semiconductor modules.

(Additional note 3)
A method for manufacturing a semiconductor module according to Supplementary Note 1,
The first solder is bonded to the insulating substrate and the base while applying vibrations generated by an ultrasonic horn that comes into contact with the first solder from the lower surface of the base after the temperature has started to decrease. is to cool the
A method for manufacturing semiconductor modules.

(Additional note 4)
A method for manufacturing a semiconductor module according to Supplementary Note 1,
The first solder is bonded to the insulating substrate and the base while applying vibrations generated by an ultrasonic horn that contacts the semiconductor element from the top surface to the first solder after the temperature has started to decrease. is to cool the
A method for manufacturing semiconductor modules.

(Appendix 5)
A method for manufacturing a semiconductor module according to any one of Supplementary Notes 1 to 4,
The bonding between the insulating substrate and the base portion is achieved by cooling the first solder while keeping the heated first solder in contact with the insulating substrate and the base portion. applying vibration to the first solder after the solder falls below a liquidus temperature;
A method for manufacturing semiconductor modules.

(Appendix 6)
A method for manufacturing a semiconductor module according to any one of Supplementary Notes 1 to 5,
the semiconductor element is bonded to the upper surface of the insulating substrate via a second solder,
the melting point of the second solder is higher than the melting point of the first solder;
A method for manufacturing semiconductor modules.

(Appendix 7)
A method for manufacturing a semiconductor module according to appendix 6,
The bonding between the insulating substrate and the base portion is achieved by cooling the first solder while keeping the heated first solder in contact with the insulating substrate and the base portion. applying vibration to the first solder after the solder reaches a temperature lower than the melting point of the second solder;
A method for manufacturing semiconductor modules.

(Appendix 8)
A method for manufacturing a semiconductor module according to any one of Supplementary Notes 1 to 7,
The base portion has a fin structure on a surface opposite to a surface to be bonded to the insulating substrate.
A method for manufacturing semiconductor modules.

(Appendix 9)
It has a semiconductor module manufactured by the manufacturing method described in any one of Supplementary Notes 1 to 8, and is provided with a conversion circuit that converts and outputs input power,
providing a control circuit that outputs a control signal to the conversion circuit for controlling the conversion circuit;
A method for manufacturing a power conversion device.

(Appendix 10)
A semiconductor element bonded to the top surface of an insulating substrate,
a base portion bonded to the insulating substrate to which the semiconductor element is bonded via a first solder;
The insulating substrate and the base section apply vibration to the first solder after the temperature starts to decrease while the heated first solder is in contact with the insulating substrate and the base section. bonding by cooling the first solder while
semiconductor module.

(Appendix 11)
A conversion circuit that includes the semiconductor module according to appendix 10 and that converts and outputs input power;
a control circuit that outputs a control signal for controlling the conversion circuit to the conversion circuit;
Power converter.

2 Semiconductor element, 30 Solder, 31 Solder, 32 Solder, 2200 Power converter, 2201 Conversion circuit, 2203 Control circuit.

Claims (11)

A semiconductor element is bonded to the top surface of an insulating substrate,
the insulating substrate to which the semiconductor element is bonded is bonded to a base portion via a first solder;
The bonding between the insulating substrate and the base portion is performed by applying vibration to the first solder after the temperature starts to decrease while the heated first solder is in contact with the insulating substrate and the base portion. cooling the first solder while giving
A method for manufacturing semiconductor modules. A method for manufacturing a semiconductor module according to claim 1,
The insulating substrate and the base portion are conveyed by a conveyor roller while being in contact with the heated first solder,
The conveyor roller includes an eccentric roller whose rotation center is shifted,
The first solder is cooled while the insulating substrate and the base are being conveyed by the conveyor roller, and the first solder is bonded to the insulating substrate and the base after the temperature starts to decrease. applying vibrations generated by the eccentric roller to the first solder when the first solder is conveyed by the eccentric roller;
A method for manufacturing semiconductor modules. A method for manufacturing a semiconductor module according to claim 1,
The first solder is bonded to the insulating substrate and the base while applying vibrations generated by an ultrasonic horn that comes into contact with the first solder from the lower surface of the base after the temperature has started to decrease. is to cool the
A method for manufacturing semiconductor modules. A method for manufacturing a semiconductor module according to claim 1,
The first solder is bonded to the insulating substrate and the base while applying vibrations generated by an ultrasonic horn that contacts the semiconductor element from the top surface to the first solder after the temperature has started to decrease. is to cool the
A method for manufacturing semiconductor modules. A method for manufacturing a semiconductor module according to claim 1 or 2,
The bonding between the insulating substrate and the base portion is achieved by cooling the first solder while keeping the heated first solder in contact with the insulating substrate and the base portion. applying vibration to the first solder after the solder falls below a liquidus temperature;
A method for manufacturing semiconductor modules. A method for manufacturing a semiconductor module according to claim 1 or 2,
the semiconductor element is bonded to the upper surface of the insulating substrate via a second solder,
the melting point of the second solder is higher than the melting point of the first solder;
A method for manufacturing semiconductor modules. A method for manufacturing a semiconductor module according to claim 6,
The bonding between the insulating substrate and the base portion is achieved by cooling the first solder while keeping the heated first solder in contact with the insulating substrate and the base portion. applying vibration to the first solder after the solder reaches a temperature lower than the melting point of the second solder;
A method for manufacturing semiconductor modules. A method for manufacturing a semiconductor module according to claim 1 or 2,
The base portion has a fin structure on a surface opposite to a surface to be bonded to the insulating substrate.
A method for manufacturing semiconductor modules. A semiconductor module manufactured by the manufacturing method according to claim 1 or 2, and a conversion circuit that converts and outputs input power,
providing a control circuit that outputs a control signal to the conversion circuit for controlling the conversion circuit;
A method for manufacturing a power conversion device. A semiconductor element bonded to the top surface of an insulating substrate,
a base portion bonded to the insulating substrate to which the semiconductor element is bonded via a first solder;
The insulating substrate and the base section apply vibration to the first solder after the temperature starts to decrease while the heated first solder is in contact with the insulating substrate and the base section. bonding by cooling the first solder while
semiconductor module. A conversion circuit comprising the semiconductor module according to claim 10 and converting and outputting input power;
a control circuit that outputs a control signal for controlling the conversion circuit to the conversion circuit;
Power converter.

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