JP6517577B2 - Power converter manufacturing method - Google Patents

Description

  The present invention relates to a method of and an apparatus for manufacturing a power conversion device, and more particularly to a method and an apparatus for manufacturing a power conversion device that can be suitably applied to a vehicle that is a hybrid vehicle.

  BACKGROUND In recent years, in vehicles such as four-wheeled vehicles, hybrid vehicles that use an engine, which is an internal combustion engine, and an electric motor in cooperation with each other in a drive system have become widespread. In such a hybrid vehicle, a power control device incorporating a power conversion device is used as one of the electronic control devices for operating the engine and the electric motor in cooperation with each other.

  The power converter includes components such as a semiconductor element joined to a predetermined arrangement position by solder, and a resin case that accommodates these components. Then, for example, each component is soldered to the predetermined arrangement position by the soldering process at the predetermined arrangement position.

  Under such circumstances, Patent Document 1 and Patent Document 2 disclose hydrogen reflow in which components are soldered to a circuit board while suppressing the oxidation of the reflow solder material by supplying hydrogen gas which is a reducing gas. A soldering process is disclosed.

  Further, Patent Document 3 discloses a formic acid reflow soldering process in which circuit boards are soldered while suppressing the oxidation of a reflow solder material by supplying a formic acid gas which is a reducing gas.

JP, 2009-253157, A JP, 2010-000513, A JP 2011-003765 A

  However, according to the study of the present inventors, Patent Documents 1 to 3 disclose or suggest reflow soldering processing that can be adapted to the manufacture of power converters consisting of various components. Absent.

  That is, in the hydrogen reflow soldering process disclosed in Patent Document 1 and Patent Document 2, the reduction start temperature of hydrogen is relatively high, and when the power converter is manufactured by the hydrogen reflow soldering process, heating is performed. Since a cover jig for suppressing the temperature rise of the resin case of the power conversion device accompanying it is required, it is considered that a large amount of processing cost and processing effort are required.

  Further, in the formic acid reflow soldering process disclosed in Patent Document 3, although the reduction start temperature of formic acid is relatively low, only the process conditions for soldering circuit boards to each other are disclosed, and the power converter It is considered that the processing conditions for soldering various components time-efficiently and freely are not considered.

  Therefore, at present, when manufacturing a power converter composed of various components, the soldering processing cost and processing labor can be reduced, and a soldering process with high time efficiency and high processing freedom is realized. There is a great demand for a method and apparatus for manufacturing a power conversion device that realizes a reflow soldering process with a novel configuration that can be performed.

  The present invention has been made through the above study, and can reduce the processing cost and processing effort of soldering when manufacturing a power converter composed of various components, and is time efficient and processed. It is an object of the present invention to provide a method of manufacturing a power conversion device realizing a reflow soldering process with a high degree of freedom and a manufacturing apparatus therefor.

In order to achieve the above object, according to a first aspect of the present invention, there is provided a semiconductor element having a first connection terminal and a second connection terminal, and a first connection member connected to the first connection terminal. A second connection member connected to the first connection member, a circuit board on which the semiconductor element is mounted, and the semiconductor element, the first connection member, the second connection member, and the circuit board are accommodated. And a resin case, wherein the first connection member is disposed between the first connection terminal and the first connection member in a method of manufacturing a power conversion device that exhibits a power conversion function by the switching operation of the semiconductor element. The semiconductor element, the first connection member, and the second connection in a mode in which solder is disposed between the second connection member and between the second connection terminal and the circuit board; Member and circuit substrate Together with the execution of the first step, and a first step of maintaining the pressure by placing the pre-structure housed in the resin case in a formic acid gas atmosphere in which the pressure is increased to a pressure higher than atmospheric pressure; The temperature of the formic acid gas atmosphere is equal to or higher than the formic acid reduction start temperature and the resin while the solder is in a molten state by heating the temperature of the preparatory structure so that the temperature of the solder is equal to or higher than the melting temperature. The formic acid gas atmosphere and the preliminary structure are heated so that the temperature of the case is less than the heat resistant lower limit temperature of the resin, the temperature of the solder, the temperature of the formic acid gas atmosphere, and the temperature of the resin case Subsequent to the second step of maintaining, and the first step and the second step, a vacuum atmosphere in which the atmosphere of formic acid gas is evacuated and discharged, and the atmosphere of the preliminary structure is reduced to a vacuum state. The first connection terminal and the first connection member, and the first connection by lowering the temperature of the molten solder to solidify the third step and the third step following the third step. A second member and the second connection member, and a fourth step of bonding the second connection terminal and the circuit board respectively with the solidified solder , wherein the spare step is performed before the first step. A jig assembly is provided by mounting the circuit board side of the structure on a pallet and mounting a jig on the semiconductor element of the preparatory structure, the first connection member and the second connection member. An upper heater for heating the jig assembly from the jig side of the jig assembly in the second step, and the jig assembly from the pallet side of the jig assembly. Using the lower heater to heat the lower The heating amount of the upper heater precedes the heating of the upper heater before the heater, and thereafter the heating of the lower heater is started with a predetermined delay time, so that the heating amount on the jig side of the jig assembly can be obtained. the degree of application than applying the degree of heating of the pallet side of the jig assembly which is a method of manufacturing a power converter Ru increased early.

The present invention, in addition to the first aspect, in the second step, after the solder was maintained in pre-heated to less than the solder melting temperature, further raising the solder above said melting temperature Warming is the second phase.

In addition to the first or second aspect of the present invention, in the first step, the atmosphere of the formic acid gas is evacuated and discharged to make the atmosphere of the preliminary structure vacuumed to a vacuum state. After that, setting the vacuum atmosphere to a formic acid gas atmosphere at a pressure higher than atmospheric pressure is a third aspect.

Further, the present invention is the first addition to the third one aspect, in the third step, a fourth aspect of maintaining the vacuum atmosphere.

Further, according to the present invention, in addition to any of the first to fourth aspects, prior to the first step, the preparatory structure is placed on a pallet and a jig is placed on the preparatory structure. A fifth aspect of the present invention is a jig assembly in which the atmosphere of the jig assembly is set to a vacuum state and then an inert gas atmosphere filled with an inert gas is set, and the inert gas atmosphere is set to a vacuum state. I assume.

Further, in addition to any one of the first to fifth aspects of the present invention, in the fourth step, the vacuum atmosphere is changed to an inert gas atmosphere subsequently to the third step, and then the molten state is obtained. A sixth aspect is to solidify by lowering the temperature of the solder.

The present invention, in addition to the sixth aspect, in the fourth step, a seventh aspect of maintaining the inert gas atmosphere above atmospheric pressure.

Further, according to the present invention, in addition to any of the first to seventh aspects, the power conversion device further includes a cooler for cooling the semiconductor element, in the spare structure, the first connection. Between the connection target surface of each of the lead frame connected to the terminal and the first connection terminal, between the connection target surface of each of the lead frame and the bus bar connected to the lead frame, the second connection terminal and the second connection terminal It is preferable that the solder is correspondingly disposed between connection target surfaces of the circuit boards connected to the second connection terminals and between connection target surfaces of the circuit board and the cooler. It shall be the eighth phase.

According to the method of manufacturing a power conversion device according to the first aspect of the present invention as described above, the semiconductor element having the first connection terminal and the second connection terminal, and the first connection connected to the first connection terminal Member, a second connection member connected to the first connection member, a circuit board on which the semiconductor element is mounted, a resin case for accommodating the semiconductor element, the first connection member, the second connection member, and the circuit board And a power conversion device exhibiting a power conversion function by the switching operation of the semiconductor device, the first connection member and the second connection between the first connection terminal and the first connection member. The semiconductor element, the first connection member, the second connection member, and the circuit board are accommodated in the resin case in a mode in which solder is disposed between the members and between the second connection terminal and the circuit board. Boost the pre-assembly to above atmospheric pressure With the execution of the first step and the first step of placing the pressure in the formic acid gas atmosphere and maintaining the pressure, the preliminary structure is heated to raise the temperature so that the temperature of the solder becomes equal to or higher than its melting temperature By heating the formic acid gas atmosphere and the preliminary structure so that the temperature of the formic acid gas atmosphere is higher than the formic acid reduction start temperature and the temperature of the resin case is less than the heat resistant lower limit temperature of the resin while The second step of maintaining the temperature of the solder, the temperature of the formic acid gas atmosphere, and the temperature of the resin case, and the first step and the second step, subsequently evacuating and discharging the formic acid gas atmosphere, and the atmosphere of the preliminary structure The third step of reducing the pressure to a vacuum state and the third step, the temperature of the molten solder is lowered subsequently to solidify the first connection terminal, the first connection member, the first Connection member and The second connecting member, and a fourth step of each joined with solder that is solidified the second connecting terminals and the circuit board, comprising a, before the first step, the palette circuit board side of the pre-structure The jig assembly is constructed by mounting the jig on the semiconductor element of the preparatory structure, the first connection member and the second connection member while mounting on the jig, and in the second step, the jig is assembled. Use the upper heater to heat the jig assembly from the jig side of the body and the lower heater to heat the jig assembly from the pallet side of the jig assembly, and let the upper heater precede the lower heater Heating of the upper heater is started, and then heating of the lower heater is started with a predetermined delay time, thereby applying the heating amount on the jig side of the jig assembly to the pallet side of the jig assembly in shall be increased earlier than the degree of applied Therefore, when manufacturing a power converter composed of various components, the processing cost and processing effort of reflow soldering can be reduced, and a reflow soldering process with high time efficiency and high processing freedom can be realized. be able to. In particular, formic acid gas can be reliably brought into contact with the solder placed in a molten state by the first step and the second step, and the reducing action of formic acid is surely exerted on the solder to oxidize them. Can be reliably suppressed. Further, at this time, it is possible to satisfy all the temperature conditions under which the solder disposed in each part melts, the temperature conditions under which the reducing action of the formic acid starts, and the temperature conditions under which the resin material of the resin case does not melt. Furthermore, in the second step, the degree of application of the heating amount on the jig side of the jig assembly is increased earlier than the degree of application of the heating amount on the pallet side of the jig assembly, so reflow soldering In processing, while causing the jig in the jig assembly to function as a secondary heat source, heat is quickly given to the solder joint portion on the jig side in the preparatory structure to appropriately melt the solder disposed in each part can do. At the same time, in the third step, the solder placed in a molten state can be solidified in a mode in which the generation of unnecessary voids is suppressed.

Further, according to the method of manufacturing a power conversion device according to the second aspect of the present invention, after the solder is preheated to a temperature lower than the melting temperature of the solder and maintained in the second step In the reflow soldering process, it is possible to appropriately raise the temperature of the solder disposed in each part to obtain a homogeneous molten state of them.

Further, according to the method of manufacturing a power conversion device in accordance with the third aspect of the present invention, in the first step, a vacuum atmosphere in which the atmosphere of formic acid gas is evacuated and discharged to reduce the atmosphere of the preparatory structure to vacuum After that, the formic acid gas atmosphere is set to a vacuum atmosphere at a pressure higher than atmospheric pressure, so formic acid gas with high purity of formic acid is brought into contact with the solder disposed in each part in the reflow soldering process. Appropriate reduction function can be exhibited.

Further, according to the method of manufacturing a power converter according to the fourth aspect of the present invention, since the vacuum atmosphere is maintained in the third step, it is disposed in each portion and melted in the reflow soldering process. Can be solidified in a mode in which the generation of unnecessary voids is further suppressed.

Further, according to the method of manufacturing a power conversion device according to the fifth aspect of the present invention, the preparatory structure is placed on the pallet and the jig is placed on the preparatory structure before the first step. As the jig assembly, the atmosphere of the jig assembly is made vacuum and then the inert gas atmosphere filled with the inert gas is made, and furthermore, the inert gas atmosphere is made vacuum, so it is arranged at each part. Unwanted components can be removed from the atmosphere of the solder by the reflow soldering process.

Further, according to the method of manufacturing a power converter according to the sixth aspect of the present invention, in the fourth step, the vacuum atmosphere is changed to an inert gas atmosphere subsequently to the third step, and then the molten solder is cooled. Since the solder solidifies, the solder placed in a molten state in each part of the reflow soldering process can be solidified in a mode in which the generation of unnecessary voids is further suppressed.

Further, according to the method of manufacturing a power conversion device according to the seventh aspect of the present invention, since the inert gas atmosphere is maintained at atmospheric pressure or higher in the fourth step, the solidification is performed by the reflow soldering process. It is possible to reduce the impurities which may be unnecessarily mixed into them from the solder atmosphere.

Further, according to the method of manufacturing a power conversion device of the eighth aspect of the present invention, the power conversion device further includes a cooler for cooling the semiconductor element, and in the spare structure, the first connection terminal and the first connection terminal The second connection terminal and the second connection terminal are connected between the connection target surface of each lead frame connected to the connection terminal 1 and the connection target surface of each of the lead frame and the bus bar connected to the lead frame Since the solder is correspondingly disposed between the connection target surfaces of the circuit boards and between the connection target surfaces of the circuit board and the cooler, the reflow soldering process of each part in the power conversion device is performed. Can be done at once.

FIG. 1 is a schematic main part cross-sectional view showing the configuration of a power conversion device manufactured by the power conversion device manufacturing apparatus and method according to an embodiment of the present invention. Fig.2 (a) is a schematic diagram which shows the structure of the manufacturing apparatus of the power converter in this embodiment, Moreover, FIG.2 (b) is a chamber of the manufacturing apparatus of the power converter shown to Fig.2 (a). It is a schematic diagram which shows the internal structure of. Fig.3 (a) is a typical principal part of the jig assembly which set the jig and the pallet to the preparatory structure of the power converter manufactured by the manufacturing apparatus and manufacturing method of the power converter in embodiment of this invention. FIG. 3B is a cross-sectional view, showing temperature characteristics, vacuum characteristics, and types of atmosphere in the chamber at the time of manufacturing by the power conversion device manufacturing apparatus and manufacturing method in the present embodiment. Fig.4 (a) is a figure which shows the heating characteristic of the upper and lower heater at the time of manufacture by the manufacturing apparatus and manufacturing method of the power converter device in this embodiment, FIG.4 (b) is a power converter device in this embodiment. It is a figure which shows the modification of the temperature characteristic at the time of manufacture of the power converter device by a manufacturing apparatus and a manufacturing method, a vacuum degree characteristic, and the kind of atmosphere in a chamber.

  Hereinafter, with reference to the drawings as appropriate, an apparatus and a method for manufacturing a power conversion device according to an embodiment of the present invention will be described in detail. In the drawing, the x-axis and the z-axis form a biaxial orthogonal coordinate system, the direction of the x-axis corresponds to the horizontal direction, and the direction of the z-axis corresponds to the vertical direction.

[Configuration of Power Converter]
First, with reference to FIG. 1, the configuration of a power conversion device manufactured by the power conversion device manufacturing apparatus and method according to the present embodiment will be described in detail.

  FIG. 1 is a schematic cross-sectional view showing the configuration of a power conversion device manufactured by the power conversion device manufacturing apparatus and method according to the present embodiment.

  As shown in FIG. 1, the power conversion device 1 is typically a water-cooled power conversion device mounted on a vehicle (not shown), and is a cooler 2 for cooling the components inside the power conversion device 1. A resin case 3 fixed on the cooler 2, a circuit board 5 housed inside the resin case 3 and joined by the solder joint 4 on the cooler 2, and an inside of the resin case 3 And a plurality of semiconductor elements 7 joined to the circuit board 5 by the solder joint 6 and electrically connected to the circuit board 5, and housed in the resin case 3 and the plurality of semiconductor elements 7. And a plurality of lead frames 91 which are correspondingly joined and electrically connected by the solder joint portion 8 and which are accommodated in the resin case 3 and are correspondingly joined by the solder joint portion 10 to the plurality of lead frames 91 Being electric It includes a plurality of bus bars 9, a to be connected to. The solder joints 4, 6, 8, 10 are each formed by solidification after the reflow solder material is melted. The end portions of the plurality of bus bars 9 may penetrate through the resin case 3 and reach the outside thereof to constitute a terminal portion.

  Such a power conversion device 1 is typically DC (Direct Current) / AC (Alternate) which converts DC power from a battery (not shown) mounted on a vehicle into power of a three-phase current and supplies it to a driving electric motor. Current) A conversion function, and an AC / DC conversion function of converting the power of the three-phase current from the regeneration mechanism into DC power and supplying it to the battery. The power conversion device 1 may have one of a DC / AC conversion function and an AC / DC conversion function as needed.

  The cooler 2 is typically a cast product made of metal such as aluminum. The cooler 2 cools the plurality of semiconductor elements 7 via the solder joint portion 4, the circuit board 5, and the solder joint portion 6 by the coolant flowing in the coolant flow path 21.

  The resin case 3 is typically a frame having a rectangular shape in a plan view, and is a molded product made of a nonconductive resin (synthetic resin), and the circuit board 5, the semiconductor element 7, the lead frame 91, And the bus bar 9 is accommodated. The heat-resistant lower limit temperature of the resin material of the resin case 3 is set higher than the melting temperature of the reflow soldering material of the solder joints 4, 6, 8, 10.

  Circuit board 5 is typically disposed parallel to a horizontal plane, is a flat DCB (Direct Copper Bond) board, and has copper circuit board 52 bonded onto insulating substrate 51 which is an alumina ceramic substrate. It is a circuit board. The lower surface of the insulating substrate 51 is joined via the solder joint portion 4 to the upper surface of the cooler 2 in which the coolant flow channel 21 is formed. The solder joint portion 6 is joined to a predetermined portion of the upper surface of the copper circuit board 52. The heat-resistant lower limit temperature of the circuit board 5 is set higher than the melting temperature of the reflow soldering material of the solder joints 4, 6, 8, 10.

  The plurality of semiconductor elements 7 are typically power semiconductor elements, and are IGBTs (Insulated Gate Bipolar Transistors) each having a collector terminal 71 and an emitter terminal 72. The plurality of semiconductor elements 7 are joined onto the copper circuit board 52 of the circuit board 5 via the solder joint portion 6 and are joined to the lead frame 91 via the solder joint portion 8. That is, in the plurality of semiconductor elements 7, the collector terminals 71 are respectively joined corresponding to the copper circuit boards 52 of the circuit board 5 via the solder joint portions 6 and electrically connected, and the emitter terminals 72 are soldered It is joined corresponding to lead frame 91 via junction part 8, and is electrically connected. The heat resistant lower limit temperature of the plurality of semiconductor elements 7 is set higher than the melting temperature of the reflow soldering material of the solder joints 4, 6, 8, 10. The relative positions of the collector terminal 71 and the emitter terminal 72 in each of the plurality of semiconductor elements 7 may be reversed in their heights according to the specification and the like.

  Lead frame 91 is typically a plate member made of metal such as steel, and is joined to and electrically connected to emitter terminal 72 of corresponding semiconductor element 7 through solder joint portion 8 and also solder It is joined and electrically connected to the corresponding bus bar 9 through the joint portion 10.

  The bus bar 9 is typically a plate member made of metal such as steel, and while extending the space between the plurality of semiconductor elements 7 in the resin case 3, both ends of the resin case are on both positive and negative sides of the x axis. 3 It has been extended outside. The bus bar 9 is joined and electrically connected to the corresponding lead frame 91 via the solder joint portion 10.

[Configuration of manufacturing apparatus of power converter]
Next, with reference to FIG. 2, the configuration of the manufacturing apparatus of the power conversion device 1 in the present embodiment will be described in detail.

  Fig.2 (a) is a schematic diagram which shows the structure of the manufacturing apparatus of the power converter device 1 in this embodiment, and FIG.2 (b) is a manufacturing apparatus of the power converter device 1 shown to Fig.2 (a). It is a schematic diagram which shows the internal structure of a chamber.

  As shown to Fig.2 (a), the manufacturing apparatus 100 of the power converter device 1 in this embodiment includes the conveyor 101, the chamber 102, the vacuum pump 104, the nitrogen gas piping 105, and the formic acid generator 106. Have. The operations of the various components of the manufacturing apparatus 100 may be controlled automatically by a controller (not shown) or manually by an operator.

  The conveyor 101 is movable through the inside of the chamber 102, and the jig assembly 110 for the power conversion device 1 to be subjected to the reflow soldering process (the jig and pallet are set in the preliminary structure, the details will be described later) ) Is placed and transported.

  The chamber 102 is a device having a heating function of heating the jig assembly 110 transported by the conveyor 101. As shown in FIG. 2B, the chamber 102 includes a plurality of upper heaters 102a for heating the jig assembly 110 from the upper surface side thereof and a plurality of lower heaters 102b for heating the jig assembly 110 from the lower surface side thereof. A plurality of exhaust ports 102c for exhausting the inside of the chamber 102, a plurality of nitrogen gas inlets 102d for introducing nitrogen gas into the chamber 102, and a plurality of formic acid gas inlets 102e for introducing formic acid gas into the chamber 102; And. Each of the plurality of upper heaters 102 a and the plurality of lower heaters 102 b is typically composed of a heating light source. Although FIG. 2B illustrates an example in which a plurality of jig assemblies 110 are introduced into the chamber 102, one jig assembly 110 is introduced into the chamber 102. It may be one. Further, the number of the chambers 102 is not particularly limited, and can be set arbitrarily.

  The vacuum pump 104 is connected to the exhaust port 102c of the chamber 102 via the exhaust pipe 104a. The vacuum pump 104 is a device for evacuating the inside of the chamber 102 by evacuating the inside of the chamber 102 through the exhaust pipe 104 a.

  The nitrogen gas pipe 105 is connected from the nitrogen gas source (not shown) to the nitrogen gas inlet 102 d of the chamber 102 and the formic acid generator 106 corresponding to the nitrogen gas source from the nitrogen gas source to the chamber 102 and the formic acid generator 106. Is a pipe that supplies In addition, inert gas other than nitrogen gas may be applied here.

  The formic acid generator 106 is connected to a formic acid gas inlet 102e of the chamber 102 through a formic acid gas pipe 106a. The formic acid generator 106 is an apparatus that generates a formic acid gas having a predetermined concentration and supplies the generated formic acid gas into the chamber 102 through a formic acid gas pipe 106 a. The practical reduction start temperature which expresses the formic acid gas reduction function is typically lower than the melting temperature of the reflow soldering material of the solder joints 4, 6, 8, 10. Further, the predetermined concentration of formic acid gas is typically a mixture of nitrogen gas supplied from a nitrogen gas source to formic acid generator 106 through nitrogen gas pipe 105 and formic acid gas generated by formic acid generator 106. can get.

[Method of Manufacturing Power Converter]
Next, with reference to FIG.3 and FIG.4, it demonstrates in detail about the manufacturing method of the power converter device 1 using the manufacturing apparatus 100 in this embodiment.

  Fig.3 (a) is a typical principal part cross section of the jig | tool assembly 110 which set the jig | tool and the pallet to the preparatory structure of the power converter 1 manufactured by the manufacturing apparatus 100 and manufacturing method in embodiment of this invention. It is a figure, FIG.3 (b) is a figure which shows the temperature characteristic at the time of manufacture by the manufacturing apparatus 100 and manufacturing method in this embodiment, a vacuum degree characteristic, and the kind of atmosphere in a chamber. FIG. 4A is a view showing the heating characteristics of the upper and lower heaters 102a and 102b at the time of manufacturing by the manufacturing apparatus 100 and the manufacturing method in the present embodiment. In FIG. 3B, the upper stage shows the temperature characteristic, the interruption shows the vacuum degree characteristic, and the lower stage shows the type of the atmosphere in the chamber.

  When manufacturing the power conversion device 1 shown in FIG. 1, first, as shown in FIG. 3A, a jig assembly in which the pallet 111 and the jig 112 are assembled to the preparatory structure 11 of the power conversion device 1. Prepare 110.

  Specifically, first, the reflow solder material 4a is disposed at the corresponding arrangement position of the circuit board 5 on the cooler 2, and the circuit board 5 is placed on the reflow solder material 4a to connect the cooler 2 The reflow soldering material 4 a is disposed between the target surface and the connection target surface of the circuit board 5. Next, the reflow soldering material 6 a is disposed at the corresponding connection position of the collector terminal 71 of the semiconductor element 7 on the circuit board 5, and the collector terminal 71 is placed on the reflow soldering material 6 a to connect the circuit board 5. The reflow soldering material 6 a is disposed between the target surface and the connection target surface of the collector terminal 71. Next, the reflow soldering material 8a is disposed at the connection position of the lead frame 91 on the emitter terminal 72 of the semiconductor element 7, and the lead frame 91 is mounted on the reflow soldering material 8a. Then, the reflow soldering material 8 a is disposed between connection target surfaces of the lead frame 91. Next, the reflow soldering material 10 a is disposed between the connection target surface of the lead frame 91 and the connection target surface of the bus bar 9 penetrating the resin case 3. Then, the resin case 3 is attached to the cooler 2 to configure the preparatory structure 11 of the power conversion device 1. The reflow soldering materials 4a, 6a, 8a, and 10a are typically lead-free reflow soldering materials, and the order of arranging them may be changed as necessary. In addition, if necessary, the reflow soldering materials 4a, 6a, 8a, 10a may not be applied at one time. For example, the reflow soldering material 4a disposed on the cooler 2 having a large heat capacity is a reflow soldering material 6a. , 8a, 10a may be applied in another reflow soldering process.

  Here, the lower portion of the preliminary structure 11 is partially accommodated and placed in a pallet 111 made of a high thermal conductivity material such as carbon, and the upper portion of the preliminary structure 11 is made of high thermal conductivity such as carbon. The jig 112 made of the elastic material is placed. Practically, when constructing the preparatory structure 11, the cooler 2 is placed on the pallet 111, and the reflow soldering material 4a is arranged at the corresponding arrangement position of the circuit board 5 on the cooler 2. Then, the reflow soldering materials 6a, 8a and 10a are sequentially arranged to constitute the preparatory structure 11, and the semiconductor element 7 and the lead frame are used to fix and hold the respective constituent elements of the preparatory structure 11 A jig assembly 110 is configured by fitting and mounting the jig 112 on the upper portion of each of the bus bar 91 and the bus bar 9 and the like. Here, in particular, the jig 112 is preferably in direct contact with or as close as possible to each of the lead frame 91 and the bus bar 9. That is, in the case where part of the lead frame 91 and the bus bar 9 contacts the resin case 3 or the like, or in the case where part of the bus bar 9 contacts the hole wall of the through hole of the resin case 3 Considering that the effective thermal conductivity of the lead frame 91 and the bus bar 9 is lowered, the temperature of the lead frame 91 and the bus bar 9 on the jig 112 side can be rapidly raised while using the jig 112 as a secondary heat source Then, the amount of heat is given more quickly to the solder joint portion on the jig 112 side, and these reflow solder materials are appropriately melted. Since the coolant is not filled in the cooler 2 on the pallet 111 side during the reflow soldering process, the thermal conductivity of the cooler 2 on the pallet 111 side is not lowered.

  Next, the jig assembly 110 thus obtained is placed on the conveyor 101, and the conveyor 101 is moved to convey the jig assembly 110 to the chamber 102 while the reflow soldering materials 4a, 6a, After melting 8a and 10a, they are solidified to produce the power conversion device 1 in which the solder joints 4, 6, 8 and 10 are formed.

  Specifically, first, at time t = 0 shown in FIG. 3B, the conveyor 101 is moved to introduce the jig assembly 110 into the chamber 102, and the upper heater 102a and the lower heater 102b are used to fix the jig assembly 110. The heating of the tool assembly 110 is started, and thereafter, the temperature characteristics of the preparatory structure 11 in the jig assembly 110, and finally, the temperature characteristics of the reflow soldering materials 4a, 6a, 8a, 10a are shown in FIG. 3 (b). It is preferable to exhibit the characteristic which combined linear temperature rising, constant temperature, and linear temperature-fall which are shown on the upper stage of. Here, as shown in FIG. 4A, at first, the jig assembly 110 is heated by only the upper heater 102a which is typically a heating light source (characteristic line L1), and the output of the upper heater 102a is a predetermined output. At time t = td1 at which PD is reached, heating of jig assembly 110 by lower heater 102b that is a heating light source is typically started (characteristic line L2), and the output of upper heater 102a is maintained at output PD ( Characteristic line L1). Then, after time t = td2 when the output of the lower heater 102b reaches the predetermined output PD, the output PD is maintained (characteristic line L2). As described above, it is the jig assembly 110 that precedes the heating of the jig assembly 110 by only the upper heater 102 a and then starts the heating of the jig assembly 110 by the lower heater 102 b with a predetermined delay time. As described above, in consideration of the tendency of the thermal conductivity on the side of the jig 112 to be lower than the thermal conductivity on the side of the pallet 111, the jig 112 in the preparatory structure 11 in the jig assembly 110 is This is because heat is given more quickly to the solder joints on the side to melt the reflow solder materials appropriately.

  Further, at time t = 0 shown in FIG. 3B, with the start of heating of the jig assembly 110, the vacuum pump 104 is driven to start the pressure reduction toward the medium vacuum level pressure P1 in the chamber 102. Do.

  Next, at time t = t1 shown in FIG. 3B, when the pressure in the chamber 102 is reduced to the medium vacuum level pressure P1 by the vacuum pump 104, the driving of the vacuum pump 104 is stopped, and the pressure is higher than atmospheric pressure. The introduction of nitrogen gas is started from the nitrogen gas pipe 105 into the chamber 102 so as to go to P2. The heating of the jig assembly 110 starting at time t = 0 may be started at time t = 1 in order to reduce power consumption due to the heating.

  Next, at time t = t2 shown in FIG. 3B, when the pressure of the nitrogen gas atmosphere in the chamber 102 reaches the pressure P2 higher than the atmospheric pressure, the vacuum pump 104 is driven to drive the inside of the chamber 102 to a medium vacuum. Reduce the pressure to the level P1. As described above, by setting the atmosphere in the chamber 102 to a nitrogen gas atmosphere, unnecessary components are removed from the atmosphere in the chamber 102 by the reflow soldering process. In addition, when the pressure in the nitrogen gas atmosphere is set to a pressurized atmosphere exceeding the atmospheric pressure, it is preferable because the unnecessary components can be more reliably removed in the reflow soldering process from the chamber 102 compared to the atmospheric pressure atmosphere. .

  Next, at time t = t3 shown in FIG. 3B, when the pressure in the chamber 102 is reduced to the medium vacuum level pressure P1, the driving of the vacuum pump 104 is stopped, and the pressure in the chamber 102 is higher than atmospheric pressure. The introduction of formic acid gas from the formic acid generator 106 into the chamber 102 is started so as to head to the pressure P2. Thereafter, when the pressure in the chamber 102 reaches the pressure P2, the drive of the formic acid generator 106 is stopped to stop the supply of formic acid gas into the chamber 102, and the pressure in the chamber 102 is maintained at the pressure P2. Here, although the temperature of the preparatory structure 11 in the jig assembly 110 at this time, and finally, the temperature T1 of the reflow soldering materials 4a, 6a, 8a, 10a is higher than the initial temperature such as room temperature It is lower than the melting temperature of the reflow soldering materials 4a, 6a, 8a, 10a. In addition, when the pressure of the formic acid gas atmosphere in the chamber 102 is a pressurized atmosphere exceeding the atmospheric pressure, the formic acid gas can be more reliably brought into contact with the reflow solder materials 4a, 6a, 8a, 10a as compared to the atmospheric pressure atmosphere. preferable.

  Next, at time t = t4 shown in FIG. 3B, the temperature of the preparatory structure 11 in the jig assembly 110, and finally, the temperature of the reflow soldering materials 4a, 6a, 8a, 10a are their melting temperatures. When temperature T2 above is reached, as shown after time t = td2 shown in FIG. 4A, the reflow solder material is controlled by controlling the output of each of upper heater 102a and lower heater 102b to be PD. The temperature of 4a, 6a, 8a, 10a is maintained at a temperature T2 above their melting temperature. Here, the temperature T2 is lower than the heat-resistant lower limit temperature T3 of the resin material of the resin case 3 accommodating the semiconductor element 7. In addition, between time t = t3 and t4, the temperature of the formic acid gas atmosphere in the chamber 102 exceeds the reduction start temperature of formic acid.

  Next, while maintaining the temperature T2 at time t = t5 shown in FIG. 3B, the formic acid gas in the chamber 102 is evacuated by driving the vacuum pump 104 to Is reduced toward the pressure P1 'at an intermediate vacuum level. As a result, generation of unnecessary voids in the reflow soldering materials 4a, 6a, 8a, 10a of the preparatory structure 11 in the jig assembly 110 is suppressed. Further, the pressure P1 'at the intermediate vacuum level at this time is preferably a pressure at the intermediate vacuum level comparable to the pressure P1 at the intermediate vacuum level at times t = t1 and t3 shown in FIG. From the viewpoint of reliably suppressing the generation of unnecessary voids in the solder members 4a, 6a, 8a, 10a, the pressure P1 ′ is preferably set to a value equal to the pressure P1.

  Next, at time t = t6 shown in FIG. 3B, when the pressure in the chamber 102 reaches the applied pressure P1 ′, the drive of the vacuum pump 104 is stopped and the applied pressure P1 ′ is maintained for a predetermined time ΔTI1. .

  Next, at time t = t6 'shown in FIG. 3B, the pressure in the chamber 102 is maintained at the applied pressure P1' for a predetermined time .DELTA.TI1, and then the pressure in the chamber 102 goes to the pressure P2 above atmospheric pressure The introduction of nitrogen gas from the nitrogen gas pipe 105 into the chamber 102 is started. Here, maintaining the pressure in the chamber 102 at the pressure P1 ′ for the predetermined time ΔTI1 causes unnecessary voids in the reflow soldering materials 4a, 6a, 8a, 10a of the preparatory structure 11 in the jig assembly 110. It is preferable from the viewpoint of more reliably suppressing the From the viewpoint of simplifying and speeding up the series of processes, the pressure in the chamber 102 is not maintained at the pressure P1 ′ at the pressure P1 ′ for a predetermined time ΔTI1, and at the timing when the pressure in the chamber 102 reaches the pressure P1 ′. The introduction of nitrogen gas may be started from the nitrogen gas pipe 105 into the chamber 102 so that the pressure in the pressure 102 is directed to the pressure P2 higher than the atmospheric pressure.

  Next, when the pressure in the chamber 102 reaches the pressure P2 higher than the atmospheric pressure at time t = t7 shown in FIG. 3B, the heating of the jig assembly 110 by the upper heater 102a and the lower heater 102b is ended. At the same time, the temperature decrease of the jig assembly 110 is started in the nitrogen gas atmosphere of the pressure P2 higher than the atmospheric pressure. At this time, the maintenance time for maintaining the temperature of the reflow soldering materials 4a, 6a, 8a, 10a of the preparatory structure 11 at the temperature T2 in the jig assembly 110 reaches the predetermined time ΔTI2. Further, by setting the atmosphere in the chamber 102 to a nitrogen gas atmosphere as described above, impurities that may be unnecessarily mixed in the reflow solder materials 4a, 6a, 8a, 10a during solidification by the reflow soldering process from the atmosphere in the chamber 102 Reduce At the same time, by setting the atmosphere in the chamber 102 to a nitrogen gas atmosphere with a pressure P2 higher than the atmospheric pressure, reflow soldering materials 4a, 6a, 8a, which solidify in the preparatory structure 11 in the jig assembly 110. The coagulation quality of each of 10a is improved. In addition, when the pressure in the nitrogen gas atmosphere in the chamber 102 is a pressurized atmosphere exceeding atmospheric pressure, the solidification quality of each of the reflow solder materials 4a, 6a, 8a, 10a can be further improved as compared to the atmospheric pressure atmosphere. preferable. The temperature may be lowered by natural cooling or by forced cooling.

  Next, at time t = t8 shown in FIG. 3B, when the temperature of the reflow soldering materials 4a, 6a, 8a and 10a of the preparatory structure 11 in the jig assembly 110 drops to a predetermined temperature, the jig is assembled. The reflow soldering materials 4a, 6a, 8a, 10a of the preliminary construction 11 in the body 110 solidify to form solder joints 4, 6, 8, 10, and the corresponding components of the preliminary construction 11 are joined by solder. Ru. At the same time, the supply of nitrogen gas is stopped and the evacuation of nitrogen gas in the chamber 102 is started by driving the vacuum pump 104.

  Next, at time t = t9 shown in FIG. 3B, when the pressure in the chamber 102 reaches the reduced pressure P1 '', the driving of the vacuum pump 104 is stopped and the chamber 102 is opened.

  Finally, after time t = t10 shown in FIG. 3B, the conveyor 101 is moved to discharge the jig assembly 110 at room temperature from the chamber 102, and reflow soldering materials 4a, 6a, 8a. The power converter 1 is obtained by removing the pallet 111 and the jig 112 from the jig assembly 110 including the preparatory structure 11 in which the solder joints 4, 6, 8, 10 are solidified by 10 a.

  Now, with regard to the method of manufacturing the power conversion device 1 using the manufacturing apparatus 100 in the present embodiment, various modifications can be considered. Therefore, referring to FIG. To explain in detail. Moreover, the structure in this modification is the same as that in this embodiment except what protrudes below.

  FIG.4 (b) is a figure which shows the modification of the temperature characteristic at the time of manufacture of the power converter device by the manufacturing apparatus and manufacturing method of the power converter device in this embodiment, a vacuum degree characteristic, and the kind of atmosphere in a chamber. In FIG. 4B, the upper stage shows the temperature characteristic, the interruption shows the vacuum degree characteristic, and the lower stage shows the type of the atmosphere in the chamber. Further, in FIG. 4B, heating of the jig assembly 110 is started at time t = 1, and formic acid gas in the chamber 102 is evacuated at time t = t5 so that the inside of the chamber 102 is at an intermediate vacuum level. The pressure is reduced to the pressure of pressure P1 and when the pressure in chamber 102 reaches pressure P1, the pressure in chamber 102 moves from pressure N2 to pressure P2 above atmospheric pressure from nitrogen gas piping 105 An example in which introduction of nitrogen gas into the chamber 102 is started is shown.

  In this modification, as shown in FIG. 4B, the melting temperatures of the reflow soldering materials 4a, 6a, 8a, 10a of the preparatory structure 11 in the jig assembly 110 from time t = t3 to t4. The temperature of the reflow soldering materials 4a, 6a, 8a, 10a is not increased linearly until the temperature T2 is reached, but the temperature is increased linearly until time t = t3 'after time t = t3. When the temperature of the heated reflow soldering materials 4a, 6a, 8a, 10a reaches a temperature T1 'below their melting temperature, it is maintained for a predetermined time .DELTA.TI3 until time t = t3' ', and subsequently the reflow soldering materials 4a , 6a, 8a and 10a are linearly raised to raise the temperature to the melting temperature T2 or more of the reflow soldering materials 4a, 6a, 8a and 10a. By performing such stepwise temperature rise, the temperature of the reflow solder materials 4a, 6a, 8a, 10a is appropriately raised to obtain a homogeneous molten state of the reflow solder materials 4a, 6a, 8a, 10a.

  Further, in this modification, at time t = t3 shown in FIG. 4B, formic acid gas is introduced into the chamber 102 from the formic acid generator 106 so that the pressure in the chamber 102 is directed to the pressure P2 higher than the atmospheric pressure. After starting, when the pressure in the chamber 102 reaches the pressure P2, the driving of the formic acid generator 106 is stopped as indicated by an alternate long and short dash line LL in the vacuum degree characteristic shown in FIG. 4 (b). Subsequently to stopping the supply of formic acid gas into the chamber 102, the formic acid gas in the chamber 102 is evacuated by driving the vacuum pump 104 to reduce the pressure in the chamber 102 to a pressure P1 at a medium vacuum level, Thereafter, the introduction of formic acid gas from the formic acid generator 106 into the chamber 102 is started again so that the pressure in the chamber 102 is directed to the pressure P2, and the pressure in the chamber 102 is As pressure P2, it may be maintained the pressure in the chamber 102 to the pressure P2. By reintroducing the formic acid gas in this manner, formic acid gas having high purity of formic acid is brought into contact with the reflow soldering materials 4a, 6a, 8a, 10a of the preparatory structure 11 in the jig assembly 110 and appropriate. Demonstrate a good reduction function. Note that such re-introduction of formic acid gas may be applied to the configuration of the present embodiment shown in FIG.

  As apparent from the above description, in the method of manufacturing the power conversion device 1 according to the present embodiment, the semiconductor element 7 having the first connection terminal 72 and the second connection terminal 71 and the first connection terminal 72 are used. The first connection member 91 to be connected, the second connection member 9 to be connected to the first connection member 91, the circuit board 5 on which the semiconductor element 7 is mounted, the semiconductor element 7, the first connection member 91, the first And a resin case 3 accommodating the connection member 9 and the circuit board 5, and a method of manufacturing the power conversion device 1 having a power conversion function by the switching operation of the semiconductor element 7, the first connection terminal 72 And the first connection member 91, the first connection member 91 and the second connection member 9, and the second connection terminal 71 and the circuit board 5 with solders 6a, 8a and 10a, respectively. In the arranged mode, semiconductor element 7. The preparatory structure 11 in which the first connection member 91, the second connection member 9, and the circuit board 5 are accommodated in the resin case 3 is placed in a formic acid gas atmosphere in which the pressure is increased to a pressure higher than atmospheric pressure. By performing the first step of maintaining the pressure and the execution of the first step, the solder 6a is heated by heating the temperature of the preparatory structure 11 so that the temperature of the solder 6a, 8a, 10a is equal to or higher than its melting temperature. , 8a and 10a in the molten state, raise the formic acid gas atmosphere and the pre-structure 11 so that the temperature of the formic acid gas atmosphere is higher than the reduction start temperature of the formic acid and the temperature of the resin case 3 is lower than the heat resistant lower limit temperature The second step of heating, maintaining the temperature of the solder 6a, 8a, 10a, the temperature of the formic acid gas atmosphere and the temperature of the resin case 3, and the first step and the second step, vacuum the formic acid gas atmosphere. And discharge A third step of reducing the atmosphere of the component 11 to a vacuum state and a third step, and subsequently cooling the melted solder 6a, 8a, 10a and solidifying the first step. The terminal 72 and the first connection member 91, the first connection member 91 and the second connection member 9, and the second connection terminal 71 and the circuit board 5 are respectively joined by the solidified solders 6, 8 and 10. Since four steps are provided, processing cost and processing labor of reflow soldering can be reduced when manufacturing the power conversion device 1 composed of various components, and time efficiency and processing freedom can be achieved. A high degree of reflow soldering process can be realized. In particular, the formic acid gas can be reliably brought into contact with the solders 6a, 8a, 10a disposed in the molten state by the first step and the second step, and such solders 6a, 8a, 10a The reducing action can be exerted reliably to suppress their oxidation. Further, at this time, the temperature conditions for melting the solder 6a, 8a, 10a arranged in each part, the temperature conditions for starting reduction action to the solder 6a, 8a, 10a to which formic acid is applied, and the resin material of the resin case 3 is melted. It is possible to satisfy all non-temperature conditions. At the same time, in the third step, the solders 6a, 8a, 10a disposed in the respective portions and brought into a molten state can be solidified in a mode in which the generation of unnecessary voids is suppressed.

  Further, in the method of manufacturing the power conversion device 1 in the present embodiment, the circuit board 5 side of the preparatory structure 11 is placed on the pallet 111 and the semiconductor element 7 of the preparatory structure 11 before the first step. The jig assembly 110 is configured by placing the jig 112 on the first connection member 91 and the second connection member 9, and in the second step, the jig assembly 110 on the jig 112 side Since the degree of application of the heating amount is increased earlier than the degree of application of the heating amount on the pallet 111 side of the jig assembly 110, the jig 112 in the jig assembly 110 is set to 2 in the reflow soldering process. While serving as the secondary heat source, heat is quickly applied to the solder joint portion on the side of the jig 112 in the preparatory structure 11, and the solder 6a, 8a, 10a disposed in each portion is appropriately melted. Can.

  Further, in the method of manufacturing the power conversion device 1 in the present embodiment, after the solder 6a, 8a, 10a is preheated to a temperature lower than the melting temperature of the solder 6a, 8a, 10a in the second step, Since the temperature of the solder 6a, 8a, 10a is raised to the melting temperature or more, the temperature of the solder 6a, 8a, 10a disposed in each part is appropriately raised in the reflow soldering process, and their homogeneity A molten state can be obtained.

  Further, in the method of manufacturing the power conversion device 1 in the present embodiment, after the formic acid gas atmosphere is evacuated and discharged in the first step, and the atmosphere of the preparatory structure 11 is reduced to a vacuum state, Since the vacuum atmosphere is a formic acid gas atmosphere in which the pressure P2 is higher than the atmospheric pressure, formic acid gas having a high purity of formic acid with respect to the solder 6a, 8a, 10a disposed in each portion in the reflow soldering process. It can be brought into contact to exert an appropriate reduction function.

  Further, in the method of manufacturing the power conversion device 1 in the present embodiment, since the vacuum atmosphere is maintained in the third step, the solder 6a disposed in a molten state in each portion in the reflow soldering process, 8a and 10a can be solidified in a mode in which the generation of unnecessary voids is further suppressed.

  Further, in the method of manufacturing the power conversion device 1 in the present embodiment, the preparatory structure 11 is placed on the pallet 111 and the jig 112 is placed on the preparatory structure 11 before the first step. Since the atmosphere of the jig assembly 110 is set to a vacuum state and then the inert gas atmosphere filled with the inert gas is set to a vacuum state, and the inert gas atmosphere is set to a vacuum state, Unwanted components can be removed from the atmosphere of the solders 6a, 8a, 10a by the reflow soldering process.

  Further, in the method of manufacturing the power conversion device 1 in the present embodiment, in the fourth step, the vacuum atmosphere is changed to an inert gas atmosphere subsequently to the third step, and then the temperature of the molten solder 6a, 8a, 10a is decreased. Since the solder solidifies, the solders 6a, 8a, 10a disposed in the molten state in the reflow soldering process can be solidified in a mode in which the generation of unnecessary voids is further suppressed.

  Further, in the method of manufacturing the power conversion device 1 in the present embodiment, since the inert gas atmosphere is maintained at atmospheric pressure or higher in the fourth step, the solders 6a and 8a being solidified by the reflow soldering process , 10a, can reduce unnecessary impurities that may be mixed into them.

  Further, in the method of manufacturing the power conversion device 1 in the present embodiment, the power conversion device 1 further includes the cooler 2 for cooling the semiconductor element 7, and in the spare structure, the first connection terminal 72 and the first connection terminal 72 A second connection terminal 71 and a second connection terminal 71 are connected between the connection target surfaces of the lead frame 91 connected to the connection terminals 72 and a connection target surface of each of the bus bars 9 connected to the lead frame 91. Solders 4a, 6a, 8a, 10a are correspondingly arranged between connection target surfaces of circuit boards 5 connected to connection terminals 71 and between connection target surfaces of circuit boards 5 and cooler 2, respectively. Therefore, the reflow soldering process of each part in the power change device 1 can be performed at one time.

  In the present invention, the type, shape, arrangement, number, and the like of members are not limited to those in the above-described embodiment, and the components of the present invention can be appropriately replaced by those having equivalent effects. Of course, changes can be made as appropriate without departing from the scope of the invention.

  As described above, the present invention can reduce the soldering processing cost and the processing labor when manufacturing a power conversion device composed of various components, and can perform soldering processing with a high degree of freedom in a time efficient manner. It is possible to provide a method and apparatus for manufacturing a power conversion device that realizes a reflow soldering process that can realize the power conversion used in vehicles such as hybrid vehicles because of its universal characteristics. It is expected that it can be widely applied to the device.

DESCRIPTION OF SYMBOLS 1 ... Power converter 2 ... Cooler 3 ... Resin case 4, 6, 8, 10 ... Solder joint part 4a, 6a, 8a, 10a ... Reflow soldering material 5 ... Circuit board 7 ... Semiconductor element 9 ... Bus bar 11 ... Preliminary composition Body 21 ... coolant flow path 51 ... insulating substrate 52 ... copper circuit board 71 ... collector terminal 72 ... emitter terminal 91 ... lead frame 100 ... manufacturing device 101 ... conveyor 102 ... chamber 102 a ... upper heater 102 b ... lower heater 102 c ... exhaust port 102 d ... Nitrogen gas inlet 102e ... Formic acid gas inlet 104 ... Vacuum pump 104a ... Exhaust pipe 105 ... Nitrogen gas piping 106 ... Formic acid generator 106a ... Formic acid gas piping 110 ... Jig assembly 111 ... Pallet 112 ... Jig

Claims (8)

A semiconductor element having a first connection terminal and a second connection terminal;
A first connection member connected to the first connection terminal;
A second connection member connected to the first connection member;
A circuit board on which the semiconductor element is mounted;
A resin case for housing the semiconductor element, the first connection member, the second connection member, and the circuit board;
In a method of manufacturing a power conversion device, the power conversion function is provided by the switching operation of the semiconductor element,
Solder is provided between the first connection terminal and the first connection member, between the first connection member and the second connection member, and between the second connection terminal and the circuit board. In the embodiment in which the semiconductor element, the first connection member, the second connection member, and the circuit board are accommodated in the resin case, the pressure is increased to a pressure higher than atmospheric pressure. A first step of maintaining the pressure in a formic acid gas atmosphere;
With the execution of the first step, the temperature of the formic acid gas atmosphere is raised while the solder is melted by heating the temperature of the preparatory structure so that the temperature of the solder is equal to or higher than the melting temperature. The temperature of the formic acid gas and the preliminary structure are raised so that the temperature above the reduction start temperature of formic acid and the temperature of the resin case become lower than the heat resistant lower limit temperature of the resin, the temperature of the solder, the formic acid gas atmosphere A second step of maintaining the temperature and the temperature of the resin case;
Subsequently to the first step and the second step, a third step of evacuating and discharging the formic acid gas atmosphere and setting the atmosphere of the preliminary structure to a vacuum atmosphere reduced to a vacuum state;
The first connection terminal and the first connection member, the first connection member, and the second connection member are obtained by cooling and solidifying the solder in the molten state subsequently to the third step. And a fourth step of respectively bonding the second connection terminal and the circuit board with the solidified solder.
Equipped with
Before the first step, the circuit board side of the preliminary structure is placed on a pallet, and the semiconductor element of the preliminary structure, the first connection member, and the second connection member are fixed. A jig assembly is constructed by mounting the tool,
In the second step, an upper heater for heating the jig assembly from the jig side of the jig assembly, and a lower heater for heating the jig assembly from the pallet side of the jig assembly And the jig assembly is started by starting heating the upper heater prior to the lower heater and starting heating the lower heater with a predetermined delay time. method of manufacturing a power converter, wherein characterized Rukoto increased earlier than applying the degree of heating of the pallet side of the application degree jig side of the heating amount the jig assembly of. The electric power according to claim 1 , wherein in the second step, the solder is preliminarily heated to a temperature lower than the melting temperature of the solder and maintained, and then the temperature of the solder is raised to the melting temperature or higher. Method of manufacturing a converter. In the first step, the formic acid gas atmosphere is evacuated and discharged, and the atmosphere of the preparatory structure is reduced to a vacuum state to make a vacuum atmosphere, and then the formic acid gas atmosphere in which the vacuum atmosphere is a pressure above atmospheric pressure The method of manufacturing a power conversion device according to claim 1 or 2 , characterized in that: The said vacuum atmosphere is maintained at said 3rd process, The manufacturing method of the power converter device in any one of Claim 1 to 3 characterized by the above-mentioned. Prior to the first step, the preparatory assembly is placed on a pallet and a jig is assembled on the preparatory assembly with a jig mounted thereon, and the atmosphere of the jig assembly is vacuumed. The method for manufacturing a power conversion device according to any one of claims 1 to 4 , wherein an inert gas atmosphere is filled with an inert gas later, and the inert gas atmosphere is further evacuated. The method according to any one of claims 1 to 5 , wherein, in the fourth step, the vacuum atmosphere is changed to an inert gas atmosphere subsequently to the third step, and then the molten solder is cooled to solidify. A method of manufacturing a power conversion device according to any one of the above. The method for manufacturing a power conversion device according to claim 6 , wherein the inert gas atmosphere is maintained at atmospheric pressure or higher in the fourth step. The power converter further includes a cooler for cooling the semiconductor device.
In the spare structure, the connection target surfaces of the lead frame and the bus bars connected to the lead frame are connected between the first connection terminals and the connection target surfaces of the lead frames connected to the first connection terminals. Between the connection target surfaces of each of the circuit boards connected to the second connection terminal and the second connection terminal, and between the connection target surfaces of the circuit board and the cooler. The method of manufacturing a power conversion device according to any one of claims 1 to 7 , wherein solder is disposed correspondingly.

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