JP6484100B2 - Method for manufacturing power conversion device - Google Patents

Description

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

  In recent years, in vehicles such as four-wheeled vehicles, hybrid vehicles using an engine that is an internal combustion engine and an electric motor in cooperation with 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 electronic control devices that operate an engine and an electric motor in cooperation.

  Such a power conversion device includes a component such as a semiconductor element joined to a predetermined arrangement position by solder, and a resin case that accommodates these components. For example, each component is joined to a predetermined arrangement position by soldering by performing a soldering process at a predetermined arrangement position.

  Under such circumstances, Patent Document 1 and Patent Document 2 describe hydrogen reflow in which component parts are soldered to a circuit board while suppressing reflow solder material from being oxidized by supplying hydrogen gas that is a reducing gas. A soldering process is disclosed.

  Patent Document 3 discloses a formic acid reflow soldering process in which circuit boards are soldered to each other while suppressing the reflow solder material from being oxidized 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 inventor, Patent Documents 1 to 3 do not disclose or suggest a reflow soldering process that can be adapted for manufacturing a power conversion device composed of various components. Absent.

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

  Moreover, in the formic acid reflow soldering process disclosed in Patent Document 3, although the formic acid reduction start temperature is relatively low, only the processing conditions for soldering the circuit boards are disclosed. It is considered that the processing conditions for soldering various components in a time efficient manner with a high degree of freedom are not considered.

  Therefore, at present, when manufacturing a power conversion device composed of various components, it is possible to reduce soldering processing costs and processing labor, and realize soldering processing with high time efficiency and high processing freedom. There is a long-awaited situation for a method of manufacturing a power conversion device that realizes a reflow soldering process having a novel configuration that can be performed, and the manufacturing device thereof.

  The present invention has been made through the above-described studies, and when manufacturing a power conversion device composed of various components, it is possible to reduce soldering processing costs and processing labor, and to improve time efficiency and processing. It is an object of the present invention to provide a method for manufacturing a power conversion device that realizes a reflow soldering process with a high degree of freedom and a manufacturing device therefor.

  In order to achieve the above object, in the first aspect of the present invention, 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; and the semiconductor element, the first connection member, the second connection member, and the circuit board. In the manufacturing method of the power converter which comprises a resin case and exhibits a power conversion function by the switching operation of the semiconductor element, between the first connection terminal and the first connection member, the first connection member And the second connection member, and between the second connection terminal and the circuit board, the semiconductor element, the first connection member, and the second connection in a form in which solder is disposed. Member and circuit base A first step of maintaining the pressure by placing the preliminary structure housed in the resin case in a formic acid gas atmosphere whose pressure is increased to a pressure equal to or higher than atmospheric pressure, and execution of the first step, The preliminary structure is heated to raise the temperature so that the temperature of the solder is less than its melting temperature and the temperature of the resin case is less than the lower temperature limit of the resin, and the temperature of the formic acid gas atmosphere is that of the formic acid. Following the second step of raising the temperature of the formic acid gas so as to be equal to or higher than the reduction start temperature, and the first step and the second step, an inert gas having the formic acid gas atmosphere at a pressure higher than atmospheric pressure. Subsequent to the third step of setting the atmosphere and the third step, the preliminary structure is further arranged so that the solder is in the molten state and the temperature of the resin case is lower than the lower limit temperature of the resin. Heat After the heating, a fourth step of maintaining the temperature of the solder and the temperature of the resin case, and during the execution of the fourth step, the inert gas atmosphere is evacuated and discharged to discharge the preliminary structure. Subsequent to the fifth step in which the atmosphere is reduced to a vacuum state and a vacuum atmosphere, and the fourth step and the fifth step, the molten solder is cooled and solidified. A sixth step of joining each of the connection terminal and the first connection member, the first connection member and the second connection member, and the second connection terminal and the circuit board with the solidified solder; , A method for manufacturing a power conversion device.

  In addition to the first aspect, the present invention places the circuit board side of the preliminary structure on a pallet before the first step, and the semiconductor element of the preliminary structure, the first A jig assembly is configured by placing a jig on one connection member and the second connection member, and in the second step, the amount of heating on the jig side of the jig assembly is determined. The second aspect is to increase the application degree earlier than the application degree of the heating amount on the pallet side of the jig assembly.

  In addition to the first or second aspect of the present invention, in the second step, the solder is preliminarily heated to a temperature lower than the melting temperature of the solder, and further maintained at the melting temperature. The third aspect is to raise the temperature as described above.

  In addition to any one of the first to third aspects, the present invention provides the first step, wherein the formic acid gas atmosphere is evacuated and discharged to reduce the atmosphere of the preliminary structure to a vacuum state. After the vacuum atmosphere is set, a formic acid gas atmosphere in which the vacuum atmosphere is set to a pressure equal to or higher than the atmospheric pressure is a fourth aspect.

  Moreover, this invention makes it 5th aspect to maintain the said vacuum atmosphere at the said 5th process in addition to any 1st to 4th aspect.

  Further, in addition to any one of the first to fifth aspects, the present invention places the preliminary structure on the pallet and mounts the jig on the preliminary structure before the first step. A sixth aspect of the present invention is to place a jig assembly on which the jig assembly is placed, to set the atmosphere of the jig assembly to a vacuum state and then to an inert gas atmosphere filled with an inert gas, and to further set the inert gas atmosphere to a vacuum state. And

  In addition to any one of the first to sixth aspects, the present invention provides the sixth step, wherein the vacuum atmosphere is changed to an inert gas atmosphere following the fifth step, and then the molten state is added. The seventh aspect is that the solder is cooled and solidified.

  In addition to the seventh aspect, the present invention has an eighth aspect in which the inert gas atmosphere is maintained at atmospheric pressure or higher in the sixth step.

  In addition to any one of the first to eighth aspects of the present invention, the power conversion device further includes a cooler that cools the semiconductor element, and the preliminary structure includes the first connection. Between the connection target surfaces of the lead frame connected to the terminal and the first connection terminal, between the connection target surfaces of the lead frame and the bus bar connected to the lead frame, the second connection terminal and the The solder is arranged correspondingly between the connection target surfaces of the circuit board connected to the second connection terminal and between the connection target surfaces of the circuit board and the cooler. Nine aspects.

  According to the method for manufacturing the power conversion device according to the first aspect of the present invention 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. A member, a second connection member connected to the first connection member, a circuit board on which the semiconductor element is mounted, and a resin case that houses the semiconductor element, the first connection member, the second connection member, and the circuit board And a method for manufacturing a power conversion device that exhibits a power conversion function by a switching operation of a semiconductor element, between the first connection terminal and the first connection member, between the first connection member and the second connection member. A spare configuration in which the semiconductor element, the first connection member, the second connection member, and the circuit board are accommodated in a resin case in a manner in which solder is disposed between the second connection terminal and the circuit board. Boost your body above atmospheric pressure The first step of maintaining the pressure in a formic acid gas atmosphere, and the execution of the first step, the solder temperature is less than its melting temperature and the resin case temperature is less than the heat resistant lower limit temperature of the resin. A second step of raising the temperature of the formic acid gas so that the temperature of the formic acid gas becomes equal to or higher than the reduction start temperature of the formic acid, and the first step; Subsequent to the second step, a third step in which the formic acid gas atmosphere is an inert gas atmosphere having a pressure higher than atmospheric pressure, and following the third step, the solder is in a molten state and the temperature of the resin case is After the preliminary structure is further heated and heated so that the temperature is lower than the heat resistant lower limit temperature of the resin, the fourth step of maintaining the temperature of the solder and the temperature of the resin case, and during the execution of the fourth step, The active gas atmosphere is evacuated and discharged Following the fifth step, in which the atmosphere of the preliminary structure is reduced to a vacuum state, and the fourth step and the fifth step, the molten solder is cooled and solidified, whereby the first connection And a sixth step of joining each of the terminal and the first connecting member, the first connecting member and the second connecting member, and the second connecting terminal and the circuit board with the solidified solder. When manufacturing a power conversion device composed of various components, it is possible to reduce reflow soldering processing cost and processing labor, and to realize reflow soldering processing with high time efficiency and high processing freedom. it can. In particular, the formic acid gas can be reliably brought into contact with the solder placed in each part and in a molten state while suppressing unnecessary reoxidation due to formic acid by the first step and the second step. It is possible to reliably suppress the oxidation by exerting the reducing action of the. At this time, all of the temperature conditions for melting the solder disposed in each part, the temperature conditions for starting the reducing action on the solder subjected to formic acid, and the temperature conditions for not melting the resin material of the resin case can be satisfied. In addition, the solder placed in each part and in a molten state can be solidified in a manner in which generation of unnecessary voids is suppressed by the third to fifth steps.

  Moreover, according to the method for manufacturing the power conversion device according to the second aspect of the present invention, before the first step, the circuit board side of the preliminary structure is placed on the pallet and the semiconductor element of the preliminary structure, A jig assembly is configured by placing a jig on the first connection member and the second connection member, and in the second step, the degree of application of the heating amount on the jig side of the jig assembly is determined. Since the heating amount is increased earlier than the degree of application of the heating amount on the pallet side of the jig assembly, the preliminary configuration is made while the jig in the jig assembly functions as a secondary heat source in the reflow soldering process. A quantity of heat can be quickly applied to the solder joint location on the jig side of the body, and the solder disposed in each part can be appropriately melted.

  Further, according to the method of manufacturing the power conversion device according to the third aspect of the present invention, in the second step, after the solder is preliminarily heated to below the melting temperature of the solder and maintained, the solder is further heated to the melting temperature or higher. Therefore, in the reflow soldering process, it is possible to appropriately raise the temperature of the solder disposed in each part and obtain a homogeneous molten state thereof.

  Further, according to the method for manufacturing the power converter according to the fourth aspect of the present invention, in the first step, the vacuum atmosphere in which the formic acid gas atmosphere is evacuated and discharged to reduce the atmosphere of the preliminary structure to a vacuum state. After that, the formic acid gas atmosphere in which the vacuum atmosphere is set to a pressure higher than the atmospheric pressure is used. Therefore, in the reflow soldering process, the formic acid gas having a high purity of formic acid is brought into contact with the solder disposed in each part. Can exhibit an appropriate reduction function.

  Further, according to the method for manufacturing the power conversion device according to the fifth aspect of the present invention, in the fifth step, the vacuum atmosphere is maintained, so in the reflow soldering process, the molten state is arranged in each part. This solder can be solidified in a manner in which generation of unnecessary voids is further suppressed.

  Moreover, according to the method for manufacturing the power conversion device according to the sixth aspect of the present invention, the preliminary structure is placed on the pallet and the jig is placed on the preliminary structure before the first step. The jig assembly is an inert gas atmosphere filled with an inert gas after the atmosphere of the jig assembly is vacuumed, and the inert gas atmosphere is vacuumed. Unnecessary components can be eliminated from the solder atmosphere by reflow soldering.

  Further, according to the method for manufacturing the power conversion device according to the seventh aspect of the present invention, in the sixth step, the vacuum atmosphere is changed to the inert gas atmosphere following the fifth step, and then the molten solder is cooled. Therefore, in the reflow soldering process, the solder disposed in each part and in a molten state can be solidified in a manner in which generation of unnecessary voids is further suppressed.

  Further, according to the method for manufacturing the power conversion device according to the eighth aspect of the present invention, in the sixth step, the inert gas atmosphere is maintained at atmospheric pressure or higher, so that it is solidified by the reflow soldering process. Impurities that can be mixed into the solder atmosphere can be reduced.

  Moreover, according to the manufacturing method of the power converter device concerning the 9th aspect of this invention, a power converter device is further equipped with the cooler which cools a semiconductor element, and a 1st connection terminal and 1st in a preliminary | backup structure. Connect between the connection target surfaces of each lead frame connected to one connection terminal, between the connection target surfaces of each lead frame and the bus bar connected to the lead frame, and connect to the second connection terminal and the second connection terminal. Reflow soldering processing of each part in the power conversion device because solder is arranged correspondingly between the connection target surfaces of the circuit board and between the connection target surfaces of the circuit board and the cooler. Can be done at once.

FIG. 1 is a schematic cross-sectional view of a main part showing a configuration of a power conversion device manufactured by a power conversion device manufacturing apparatus and a manufacturing method according to an embodiment of the present invention. FIG. 2A is a schematic diagram showing a configuration of a power conversion device manufacturing apparatus according to the present embodiment, and FIG. 2B is a chamber of the power conversion device manufacturing apparatus shown in FIG. It is a schematic diagram which shows the internal structure. FIG. 3A is a schematic main part of a jig assembly in which a jig and a pallet are set on a preliminary structure of the power conversion apparatus manufactured by the power conversion apparatus manufacturing apparatus and manufacturing method according to the embodiment of the present invention. FIG. 3B is a diagram showing the temperature characteristics, the vacuum characteristics, and the types of atmospheres in the chamber at the time of manufacturing by the power conversion apparatus manufacturing apparatus and manufacturing method according to the present embodiment. FIG. 4A is a diagram showing the heating characteristics of the upper and lower heaters during manufacturing by the power conversion device manufacturing apparatus and manufacturing method according to the present embodiment, and FIG. 4B is a diagram of the power conversion device according to the present 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, a manufacturing apparatus and a manufacturing method of a power conversion device according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In the figure, the x-axis and the z-axis form a biaxial orthogonal coordinate system, the x-axis direction corresponds to the horizontal direction, and the z-axis direction corresponds to the up-down direction.

[Configuration of power converter]
First, with reference to FIG. 1, it demonstrates in detail about the structure of the power converter device manufactured by the manufacturing apparatus and manufacturing method of the power converter device in this embodiment.

  FIG. 1 is a schematic cross-sectional view of a main part showing a configuration of a power conversion device manufactured by a power conversion device manufacturing apparatus and a manufacturing 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 a cooler 2 that cools components inside the power conversion device 1. A resin case 3 fixed on the cooler 2, a circuit board 5 accommodated in the resin case 3 and joined to the cooler 2 by the solder joint 4, and the interior of the resin case 3 And a plurality of semiconductor elements 7 joined to the circuit board 5 by the solder joints 6 and electrically connected to the circuit board 5, and housed in the resin case 3 and a plurality of semiconductor elements 7. A plurality of lead frames 91 that are correspondingly joined and electrically connected to each other by the solder joints 8, and accommodated inside the resin case 3 and correspondingly joined to the plurality of lead frames 91 by the solder joints 10. 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 solidifying after the reflow solder material is melted. Note that the end portions of the plurality of bus bars 9 may penetrate the resin case 3 and reach the outside thereof to constitute terminal portions.

  Such a power conversion device 1 is typically mounted on a vehicle and converts DC power from a battery (not shown) into three-phase current power and supplies it to a drive electric motor DC (Direct Current) / AC (Alternate). Current) conversion function and an AC / DC conversion function for 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 necessary.

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

  The resin case 3 is typically a rectangular frame in plan view, and is a molded product made of non-conductive resin (synthetic resin). 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 solder material of the solder joints 4, 6, 8, and 10.

  The circuit board 5 is typically a flat DCB (Direct Copper Bond) board disposed in parallel to a horizontal plane, and a copper circuit board 52 is bonded on an insulating board 51 which is an alumina ceramic board. Circuit board. The lower surface of the insulating substrate 51 is bonded to the upper surface of the cooler 2 in which the coolant channel 21 is formed via the solder bonding portion 4. A solder joint 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 solder 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) having a collector terminal 71 and an emitter terminal 72. The plurality of semiconductor elements 7 are bonded onto the copper circuit board 52 of the circuit board 5 via the solder bonding portion 6 and are bonded to the lead frame 91 via the solder bonding portion 8. That is, in each of the plurality of semiconductor elements 7, the collector terminal 71 is joined and electrically connected to the copper circuit board 52 of the circuit board 5 via the solder joint portion 6, and the emitter terminal 72 is soldered. They are joined and electrically connected to the lead frame 91 via the joint 8. The minimum heat-resistant temperature of the plurality of semiconductor elements 7 is set higher than the melting temperature of the reflow solder material of the solder joints 4, 6, 8, 10. Note that 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 depending on the specifications and the like.

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

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

[Configuration of power converter manufacturing equipment]
Next, with reference to FIG. 2, it demonstrates in detail about the structure of the manufacturing apparatus of the power converter device 1 in this embodiment.

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

  As shown in FIG. 2 (a), the manufacturing apparatus 100 of the power conversion apparatus 1 in this embodiment includes a conveyor 101, a chamber 102, a vacuum pump 104, a nitrogen gas pipe 105, and a formic acid generator 106. I have. Operations of various components of the manufacturing apparatus 100 may be automatically controlled by a controller (not shown) or may be manually performed by an operator.

  The conveyor 101 is movable through the chamber 102, and a jig assembly 110 (a jig and a pallet are set on a preliminary construction body with respect to the power conversion apparatus 1 to be subjected to reflow soldering processing. Details will be described later. Is a device for carrying and transporting.

  The chamber 102 is a device having a heating function for heating the jig assembly 110 conveyed 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 its upper surface side, and a plurality of lower heaters 102b for heating the jig assembly 110 from its lower surface side. A plurality of exhaust ports 102c for exhausting the inside of the chamber 102, a plurality of nitrogen gas introduction ports 102d for introducing nitrogen gas into the chamber 102, and a plurality of formic acid gas introduction ports 102e for introducing formic acid gas into the chamber 102, It is equipped with. Each of the plurality of upper heaters 102a and the plurality of lower heaters 102b is typically composed of a heating light source. In FIG. 2B, a mode in which a plurality of jig assembly bodies 110 are introduced into the chamber 102 is illustrated, but one jig assembly body 110 is introduced into the chamber 102. It may be a thing. The number of 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 through the exhaust pipe 104a. The vacuum pump 104 is a device that evacuates the chamber 102 via the exhaust pipe 104a to bring the chamber 102 into a vacuum state.

  The nitrogen gas pipe 105 is connected from a nitrogen gas source (not shown) corresponding to the nitrogen gas inlet 102d of the chamber 102 and the formic acid generator 106. The nitrogen gas pipe 105 is connected to the chamber 102 and the formic acid generator 106 from the nitrogen gas source. It is a piping which supplies. Here, an inert gas other than nitrogen gas may be applied.

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

[Manufacturing method of 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. 3A is a schematic cross-sectional view of a main part of a jig assembly 110 in which a jig and a pallet are set on a preliminary structure of the power conversion apparatus 1 manufactured by the manufacturing apparatus 100 and the manufacturing method according to the embodiment of the present invention. FIG. 3B is a diagram showing temperature characteristics, vacuum characteristics, and types of atmospheres in the chamber during manufacturing by the manufacturing apparatus 100 and the manufacturing method according to the present embodiment. FIG. 4A is a diagram illustrating the heating characteristics of the upper and lower heaters 102a and 102b during manufacturing by the manufacturing apparatus 100 and the manufacturing method according to the present embodiment. In FIG. 3B, the upper stage shows the temperature characteristics, the interruption shows the vacuum degree characteristics, and the lower stage shows the type of atmosphere in the chamber.

  When the power converter 1 shown in FIG. 1 is manufactured, first, as shown in FIG. 3A, a jig assembly in which the pallet 111 and the jig 112 are assembled to the preliminary structure 11 of the power converter 1. 110 is prepared.

  Specifically, first, the reflow solder material 4a is arranged at a 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 solder material 4 a is disposed between the target surface and the connection target surface of the circuit board 5. Next, the reflow solder material 6a is disposed at a 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 solder material 6a to connect the circuit board 5. The reflow solder material 6 a is disposed between the target surface and the connection target surface of the collector terminal 71. Next, the reflow solder material 8 a 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 placed on the reflow solder material 8 a to connect the connection surface of the emitter terminal 72. The reflow solder material 8 a is disposed between the connection target surfaces of the lead frame 91. Next, the reflow solder 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 that penetrates the resin case 3. And the preliminary | backup structure 11 of the power converter device 1 is comprised by attaching the resin case 3 to the cooler 2. FIG. The reflow solder materials 4a, 6a, 8a, and 10a are typically lead-free reflow solder materials, and the order in which they are arranged may be changed as necessary. Moreover, it is not necessary to apply the reflow solder materials 4a, 6a, 8a and 10a at a time if necessary. For example, the reflow solder material 4a disposed on the cooler 2 having a large heat capacity is replaced with the reflow solder material 6a. , 8a and 10a may be applied in a reflow soldering process different from the reflow soldering process.

  Here, the lower part of the preliminary structure 11 is partly accommodated and placed on a pallet 111 made of a high thermal conductivity material such as carbon, and the high thermal conductivity of carbon or the like is placed on the upper part of the preliminary structure 11. A jig 112 made of a functional material is placed. Practically, when the preliminary structure 11 is configured, the cooler 2 is placed on the pallet 111, and the reflow solder material 4a is placed at the corresponding placement position of the circuit board 5 on the cooler 2. Then, in order to arrange the reflow solder materials 6a, 8a and 10a in order to form the preliminary structure 11, and to fix and hold each component of the preliminary structure 11, the semiconductor element 7 and the lead frame The jig assembly 110 is configured by fitting and placing the jig 112 on the upper part of each of 91 and the bus bar 9. Here, in particular, the jig 112 is preferably in direct contact with each of the lead frame 91 and the bus bar 9 or as close as possible. This is because when the lead frame 91 and a part of the bus bar 9 are in contact with the resin case 3 or the like, or when a part of the bus bar 9 is extended while being in contact with 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 lead frame 91 and the bus bar 9 on the jig 112 side are quickly heated while the jig 112 is used as a secondary heat source. Then, the amount of heat is quickly given to the solder joint portion on the jig 112 side, and those reflow solder materials are appropriately melted. In addition, 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 obtained in this way is placed on the conveyor 101, and the reflow solder materials 4a, 6a, The power conversion device 1 in which the solder joints 4, 6, 8, and 10 are formed is manufactured by melting and solidifying 8a and 10a.

  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 cure. The heating of the tool assembly 110 is started, and thereafter, the temperature characteristics of the preliminary structure 11 in the jig assembly 110, that is, the temperature characteristics of the reflow solder materials 4a, 6a, 8a, and 10a are shown in FIG. It is preferable to exhibit characteristics combining the linear temperature rise, the constant temperature, and the linear temperature drop shown in the upper stage. Here, as shown in FIG. 4A, initially, the jig assembly 110 is typically heated only by the upper heater 102a which is a heating light source (characteristic line L1), and the output of the upper heater 102a is a predetermined output. At time t = td1 when reaching the PD, heating of the jig assembly 110 is typically started by the lower heater 102b, which is a heating light source (characteristic line L2), and the output of the upper heater 102a is maintained at the 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). The heating of the jig assembly 110 by only the upper heater 102a precedes the heating of the jig assembly 110 by the lower heater 102b after a predetermined delay time. As described above, in consideration of the fact that the thermal conductivity on the jig 112 side tends to be lower than the thermal conductivity on the pallet 111 side, the jig 112 in the preliminary structure 11 in the jig assembly 110. This is because the reflow solder material is appropriately melted by quickly applying a heat quantity to the solder joint portion on the side.

  In addition, at time t = 0 shown in FIG. 3B, as the jig assembly 110 starts to be heated, the vacuum pump 104 is driven to start depressurization in the chamber 102 toward the medium vacuum level pressure P1. To do.

  Next, at time t = t1 shown in FIG. 3 (b), when the inside of the chamber 102 is depressurized by the vacuum pump 104 to a medium vacuum level pressure P1, the driving of the vacuum pump 104 is stopped, and the pressure equal to or higher than the atmospheric pressure. Nitrogen gas introduction is started from the nitrogen gas pipe 105 into the chamber 102 toward 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 heating.

  Next, at time t = t2 shown in FIG. 3B, when the pressure of the nitrogen gas atmosphere in the chamber 102 reaches a pressure P2 that is equal to or higher than the atmospheric pressure, the inside of the chamber 102 is evacuated by driving the vacuum pump 104. Reduce pressure to level pressure P1. Thus, by setting the atmosphere in the chamber 102 to a nitrogen gas atmosphere, unnecessary components are eliminated from the atmosphere in the chamber 102 by the reflow soldering process. Further, it is preferable that the pressure in the nitrogen gas atmosphere exceeds the atmospheric pressure in the chamber 102 because unnecessary components can be more reliably removed from the chamber 102 by reflow soldering than in the atmospheric pressure atmosphere. .

  Next, at time t = t3 shown in FIG. 3B, when the inside of the chamber 102 is depressurized to the pressure P1 of the medium vacuum level, the driving of the vacuum pump 104 is stopped, and the pressure in the chamber 102 is over atmospheric pressure. Formic acid gas starts to be introduced into the chamber 102 from the formic acid generator 106 so as to reach the pressure P2. Thereafter, when the pressure in the chamber 102 reaches the pressure P2, the driving of the formic acid generator 106 is stopped, the supply of the formic acid gas into the chamber 102 is stopped, and the pressure in the chamber 102 is maintained at the pressure P2. Here, the temperature of the preliminary structure 11 in the jig assembly 110 at this time, that is, the temperature T1 of the reflow solder materials 4a, 6a, 8a, and 10a is higher than the initial temperature such as room temperature. It is lower than the melting temperature of the reflow solder materials 4a, 6a, 8a and 10a. Further, if the pressure of the formic acid gas atmosphere exceeds the atmospheric pressure in the chamber 102, the formic acid gas can be brought into contact with the reflow solder materials 4a, 6a, 8a, and 10a more reliably than in the atmospheric pressure atmosphere. preferable.

  Next, in a state where the pressure in the chamber 102 is maintained at the pressure P2, and the temperature of the preliminary structure 11 in the jig assembly 110, that is, the temperatures of the reflow solder materials 4a, 6a, 8a, and 10a, At the time t = t3a shown in FIG. 3B, which is the timing before reaching the temperature T2 equal to or higher than the melting temperature, the nitrogen gas pipe 105 is discharged while the formic acid gas in the chamber 102 is discharged by driving the vacuum pump 104. Then, nitrogen gas is introduced into the chamber 102 to replace the formic acid gas atmosphere in the chamber 102 with a nitrogen gas atmosphere. Thereby, formic acid is pulled out of the chamber 102 at an early stage, and unnecessary oxidation due to formic acid is suppressed. Here, during the time t = t3 to t3a shown in FIG. 3B, the temperature of the formic acid gas atmosphere in the chamber 102 exceeds the formic acid reduction start temperature.

  Next, at the time t = t4 shown in FIG. 3B, the temperature of the preliminary structure 11 in the jig assembly 110, that is, the temperatures of the reflow solder materials 4a, 6a, 8a, and 10a are their melting temperatures. When the above temperature T2 is reached, the reflow solder material is controlled by maintaining the output of each of the upper heater 102a and the lower heater 102b in the PD as shown after time t = td2 shown in FIG. The temperatures of 4a, 6a, 8a, and 10a are maintained at a temperature T2 that is equal to or higher than their melting temperature. Here, the temperature T <b> 2 is a temperature lower than the heat resistant lower limit temperature T <b> 3 of the resin material of the resin case 3 that houses the semiconductor element 7. In addition, between time t = t3 and t4, the pressure in the chamber 102 reaches the pressure P2 and is maintained.

  Next, at time t = t5 shown in FIG. 3B, while maintaining the temperature T2, the vacuum pump 104 is driven to evacuate the nitrogen gas in the chamber 102, and the chamber 102 Is reduced to a pressure P1 ′ at a medium vacuum level. This suppresses generation of unnecessary voids in the reflow solder materials 4a, 6a, 8a, and 10a of the preliminary structure 11 in the jig assembly 110. At this time, the medium vacuum level pressure P1 ′ is preferably set to a medium vacuum level pressure similar to the medium vacuum level pressure P1 at times t = t1 and t3 shown in FIG. From the viewpoint of reliably suppressing the generation of unnecessary voids in the solder materials 4a, 6a, 8a, and 10a, it is preferable to set the pressure P1 ′ to a value equal to the pressure P1.

  Next, when the pressure in the chamber 102 reaches the pressure P1 ′ at time t = t6 shown in FIG. 3B, the driving of the vacuum pump 104 is stopped and the 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 ΔTI1, and then the pressure in the chamber 102 moves toward the pressure P2 that is equal to or higher than atmospheric pressure. Then, 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 a predetermined time ΔTI1 generates unnecessary voids in the reflow solder materials 4a, 6a, 8a, and 10a of the preliminary structure 11 in the jig assembly 110. This is preferable from the viewpoint of more reliably suppressing the operation. From the viewpoint of simplifying and speeding up a series of processes, the pressure in the chamber 102 is maintained at the pressure P1 ′ at the timing when the pressure in the chamber 102 reaches the pressure P1 ′ without maintaining the pressure P1 ′ for a predetermined time ΔTI1. The introduction of nitrogen gas from the nitrogen gas pipe 105 into the chamber 102 may be started so that the pressure in the gas 102 is directed to a pressure P2 that is equal to or higher than atmospheric pressure.

  Next, when the pressure in the chamber 102 reaches a pressure P2 that is equal to or 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 finished. At the same time, the temperature of the jig assembly 110 starts to be lowered in a nitrogen gas atmosphere having a pressure P2 equal to or higher than atmospheric pressure. At this time, the maintenance time during which the temperature of the reflow solder materials 4a, 6a, 8a, and 10a of the preliminary structure 11 in the jig assembly 110 is maintained at the temperature T2 reaches a predetermined time ΔTI2. Further, by making the atmosphere in the chamber 102 a nitrogen gas atmosphere in this way, impurities that can be mixed into the reflow solder materials 4a, 6a, 8a, and 10a that are solidified from the atmosphere in the chamber 102 by reflow soldering processing. Reduce. At the same time, by setting the atmosphere in the chamber 102 to a nitrogen gas atmosphere having a pressure P2 equal to or higher than the atmospheric pressure in this way, the reflow solder materials 4a, 6a, 8a, which solidify in the preliminary structure 11 in the jig assembly 110, The solidification quality of each of 10a is improved. Further, if the pressure in the nitrogen gas atmosphere exceeds the atmospheric pressure in the chamber 102, the solidification quality of each of the reflow solder materials 4a, 6a, 8a, and 10a can be further improved as compared with the atmospheric pressure atmosphere. preferable. The temperature drop may be due to natural cooling or forced cooling.

  Next, when the temperature of the reflow solder materials 4a, 6a, 8a and 10a of the preliminary structure 11 in the jig assembly 110 decreases to a predetermined temperature at time t = t8 shown in FIG. The reflow solder materials 4a, 6a, 8a, and 10a of the preliminary structure 11 in the body 110 are solidified to become solder joints 4, 6, 8, and 10, and the corresponding components of the preliminary structure 11 are bonded by solder. The At the same time, the supply of nitrogen gas is stopped and the vacuum pump 104 is driven to start discharging the nitrogen gas in the chamber 102.

  Next, when the pressure in the chamber 102 reaches the reduced pressure P1 ″ at time t = t9 shown in FIG. 3B, 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, and the jig assembly 110 that has reached room temperature is discharged from the chamber 102, and the reflow solder materials 4a, 6a, 8a are discharged. The power conversion apparatus 1 is obtained by removing the pallet 111 and the jig 112 from the jig assembly 110 including the preliminary structure 11 in which the solder joints 4, 6, 8, and 10 are solidified.

  Now, since various modifications can be considered for the method of manufacturing the power conversion apparatus 1 using the manufacturing apparatus 100 in the present embodiment, hereinafter, with reference to FIG. This will be described in detail. Further, the configuration in the present modification is the same as that in the present embodiment except for the following projection.

  FIG. 4B is a diagram illustrating a modification of the temperature characteristics, the vacuum characteristics, and the type of atmosphere in the chamber when the power converter according to the present embodiment is manufactured. In FIG. 4B, the upper stage shows temperature characteristics, the interruption shows vacuum characteristics, and the lower stage shows types of chamber atmospheres. 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 a medium vacuum level. The pressure to be reduced to the pressure of the pressure is set to the pressure P1, and at the timing when the pressure in the chamber 102 reaches the pressure P1, the pressure in the chamber 102 is directed from the nitrogen gas pipe 105 so as to go to the pressure P2 that is equal to or higher than atmospheric pressure. An example is shown in which introduction of nitrogen gas into the chamber 102 is started.

  In this modification, as shown in FIG. 4B, the melting temperature of the reflow solder materials 4a, 6a, 8a, and 10a of the preliminary structure 11 in the jig assembly 110 between time t = t3 and t4. The temperature of the reflow solder materials 4a, 6a, 8a, and 10a is not increased linearly until reaching the above temperature T2, but increases linearly until then at time t = t3 ′ after time t = t3. When the temperature of the reflow solder materials 4a, 6a, 8a, and 10a that have been heated reaches a temperature T1 ′ that is lower than their melting temperature, the temperature is maintained for a predetermined time ΔTI3 until time t = t3 ″, and then the reflow solder material 4a. , 6a, 8a, and 10a are linearly increased to raise the temperature stepwise to a temperature equal to or higher than the melting temperature T2 of the reflow solder materials 4a, 6a, 8a, and 10a. By executing such stepwise temperature increase, the temperature of the reflow solder materials 4a, 6a, 8a, and 10a is appropriately increased to obtain a homogeneous molten state of the reflow solder materials 4a, 6a, 8a, and 10a. The timing time t = t3a for replacing the formic acid gas atmosphere in the chamber 102 with a nitrogen gas atmosphere is typically set between the times t = t3 and t4.

  Further, in this modification, 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 a pressure P2 that is equal to or higher than atmospheric pressure at time t = t3 shown in FIG. After that, when the pressure in the chamber 102 reaches the pressure P2, the driving of the formic acid generator 106 is stopped as indicated by the alternate long and short dash line LL in the vacuum characteristic shown in FIG. Subsequent 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, and the inside of the chamber 102 is depressurized to a pressure P1 at a medium vacuum level, Thereafter, introduction of formic acid gas into the chamber 102 from the formic acid generator 106 is started again so that the pressure in the chamber 102 is directed toward the pressure P2, and the pressure in the chamber 102 is increased. 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, the formic acid gas having a high purity of formic acid is brought into contact with the reflow solder materials 4a, 6a, 8a, and 10a of the preliminary structure 11 in the jig assembly 110 so as to be appropriate. To show a good reduction function. Note that the reintroduction of the formic acid gas may be applied to the degree of vacuum characteristics of the present embodiment shown in FIG.

  As apparent from the above description, in the method for manufacturing the power conversion device 1 in 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 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 that accommodates the connection member 9 and the circuit board 5, and a method for manufacturing the power conversion device 1 that exhibits a power conversion function by the switching operation of the semiconductor element 7, and includes a first connection terminal 72. And solder 6a, 8a, 10a between the first connecting member 91, between the first connecting member 91 and the second connecting member 9, and between the second connecting terminal 71 and the circuit board 5, respectively. The semiconductor element 7. The preliminary 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 that is pressurized to a pressure equal to or higher than atmospheric pressure. Along with the execution of the first step for maintaining the pressure and the first step, the preliminary operation is performed so that the temperature of the solder 6a, 8a, 10a is lower than the melting temperature and the temperature of the resin case 3 is lower than the heat resistant lower limit temperature of the resin. A second step of heating the component 11 to raise the temperature, and raising the temperature of the formic acid gas so that the temperature of the formic acid gas is equal to or higher than the reduction start temperature of the formic acid; the first step and the second step Subsequent to the step, the third step in which the formic acid gas atmosphere is an inert gas atmosphere having a pressure equal to or higher than the atmospheric pressure, and the third step, the solders 6a, 8a, 10a are in a molten state, and the resin case 3 Temperature is the lower temperature limit of the resin After the preliminary structure 11 is further heated and heated so that it is full, the fourth step of maintaining the temperatures of the solders 6a, 8a and 10a and the temperature of the resin case 3 and during the execution of the fourth step Next, a fifth step of changing the atmosphere of the preliminary structure 11 to a vacuum atmosphere in which the inert gas atmosphere is evacuated and discharged to a vacuum state, and the molten solder following the fourth step and the fifth step. 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 And a sixth step of joining the circuit board 5 with the solidified solders 6, 8, and 10, respectively. Therefore, when the power conversion device 1 composed of various components is manufactured, reflow soldering is performed. Reduce processing costs and processing effort It is possible to realize a reflow soldering process that is time efficient and has a high degree of processing freedom. In particular, the formic acid gas can be reliably brought into contact with the solder 6a, 8a, 10a disposed in each part and in a molten state while suppressing unnecessary reoxidation due to formic acid by the first step and the second step. The solder 6a, 8a, 10a can be reliably reduced by formic acid and the oxidation thereof can be reliably suppressed. At this time, the temperature conditions for melting the solders 6a, 8a, 10a arranged in the respective parts, the temperature conditions for starting the reducing action on the solders 6a, 8a, 10a to which formic acid is applied, and the resin material of the resin case 3 are melted. It is possible to satisfy all the temperature conditions that are not performed. At the same time, the solders 6a, 8a, and 10a disposed in the respective portions and in a molten state can be solidified in a manner in which generation of unnecessary voids is suppressed by the third to fifth steps.

  Moreover, in the manufacturing method of the power converter 1 in this embodiment, before the 1st process, the circuit board 5 side of the preliminary | backup structure 11 is mounted on the pallet 111, and the semiconductor element 7 of the backup | preliminary structure 11, 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 is arranged on the jig 112 side. Since the application degree of the heating amount is increased earlier than the application degree of the heating amount on the pallet 111 side of the jig assembly 110, two jigs 112 in the jig assembly 110 are added in the reflow soldering process. While functioning as a secondary heat source, heat is quickly applied to the solder joint portion on the jig 112 side of the preliminary structure 11 to appropriately melt the solder 6a, 8a, 10a disposed in each part. Can.

  Moreover, in the manufacturing method of the power converter device 1 in the present embodiment, after the solder 6a, 8a, and 10a are preliminarily heated to below the melting temperature of the solder 6a, 8a, and 10a and maintained in the second step, Since the solder 6a, 8a, 10a is heated to a melting temperature or higher, in the reflow soldering process, the temperature of the solder 6a, 8a, 10a disposed in each part is appropriately raised, and their homogeneous A molten state can be obtained.

  Moreover, in the manufacturing method of 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 preliminary structure 11 is reduced to a vacuum state, Since the vacuum atmosphere is a formic acid gas atmosphere having a pressure P2 equal to or higher than atmospheric pressure, formic acid gas having a high purity of formic acid is applied to the solders 6a, 8a, and 10a arranged in each part in the reflow soldering process. An appropriate reduction function can be exhibited by contact.

  Moreover, in the manufacturing method of the power conversion device 1 in the present embodiment, since the vacuum atmosphere is maintained in the fifth step, the solder 6a disposed in each part and brought into a molten state in the reflow soldering process, 8a and 10a can be solidified in such a manner that generation of unnecessary voids is further suppressed.

  Further, in the method for manufacturing the power conversion device 1 according to the present embodiment, before the first step, the spare structure 11 is placed on the pallet 111 and the jig 112 is placed on the spare structure 11. Since the tool assembly 110 is an inert gas atmosphere filled with an inert gas after the atmosphere of the jig assembly 110 is set to a vacuum state, and the inert gas atmosphere is set to a vacuum state, the jig assembly body 110 is disposed in each part. Unnecessary components can be eliminated by reflow soldering from the atmosphere of the solder 6a, 8a, 10a.

  Moreover, in the manufacturing method of the power converter device 1 in the present embodiment, in the sixth step, the vacuum atmosphere is changed to the inert gas atmosphere following the fifth step, and then the molten solders 6a, 8a, and 10a are cooled. Therefore, in the reflow soldering process, the solders 6a, 8a, and 10a that are disposed in the respective portions and are in a molten state can be solidified in a manner in which generation of unnecessary voids is further suppressed.

  Moreover, in the manufacturing method of the power converter device 1 in this embodiment, since the inert gas atmosphere is maintained at atmospheric pressure or higher in the sixth step, the solders 6a and 8a being solidified by the reflow soldering process. Impurities that can be mixed into the 10a atmosphere can be reduced.

  Moreover, in the manufacturing method of the power converter device 1 in this embodiment, the power converter device 1 is further provided with the cooler 2 which cools the semiconductor element 7, and in the preliminary structure, the first connection terminal 72 and the first Between the connection target surfaces of the lead frame 91 connected to the connection terminal 72, between the connection target surfaces of the lead frame 91 and the bus bar 9 connected to the lead frame 91, the second connection terminal 71 and the second connection terminal 72. Solders 4a, 6a, 8a, and 10a are arranged correspondingly between the connection target surfaces of the circuit board 5 connected to the connection terminal 71 and between the connection target surfaces of the circuit board 5 and the cooler 2. Therefore, the reflow soldering process of each part in the power change device 1 can be performed at a time.

  In the present invention, the type, shape, arrangement, number, and the like of the members are not limited to the above-described embodiment, and the gist of the invention is appropriately replaced such that the constituent elements are appropriately replaced with those having the same operational effects. Of course, it can be changed as appropriate without departing from the scope.

  As described above, according to the present invention, when manufacturing a power conversion device composed of various components, it is possible to reduce soldering processing cost and processing labor, and to perform time-efficient and highly flexible soldering processing. A power conversion device manufacturing method that realizes reflow soldering processing and a manufacturing device therefor can be provided, and power conversion used for a vehicle such as a hybrid vehicle due to its universal character It is expected to be widely applicable to devices.

DESCRIPTION OF SYMBOLS 1 ... Power converter 2 ... Cooler 3 ... Resin case 4, 6, 8, 10 ... Solder junction part 4a, 6a, 8a, 10a ... Reflow solder material 5 ... Circuit board 7 ... Semiconductor element 9 ... Bus bar 11 ... Preliminary structure Body 21 ... Coolant passage 51 ... Insulating substrate 52 ... Copper circuit board 71 ... Collector terminal 72 ... Emitter terminal 91 ... Lead frame 100 ... Manufacturing apparatus 101 ... Conveyor 102 ... Chamber 102a ... Upper heater 102b ... Lower heater 102c ... Exhaust port 102d ... Nitrogen gas inlet 102e ... Formic acid gas inlet 104 ... Vacuum pump 104a ... Exhaust pipe 105 ... Nitrogen gas pipe 106 ... Formic acid generator 106a ... Formic acid gas pipe 110 ... Jig assembly 111 ... Pallet 112 ... Jig

Claims (9)

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 connecting member connected to the first connecting member;
A circuit board on which the semiconductor element is mounted;
A resin case for housing the semiconductor element, the first connecting member, the second connecting member, and the circuit board;
And a method for manufacturing a power conversion device that exhibits a power conversion function by a switching operation of the semiconductor element,
Solder 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, respectively. In a mode in which the semiconductor element, the first connection member, the second connection member, and the circuit board are accommodated in the resin case, the preliminary structure is increased to a pressure equal to or higher than the atmospheric pressure. A first step of maintaining the pressure in a formic acid gas atmosphere;
With the execution of the first step, the preliminary structure is heated to raise the temperature so that the temperature of the solder is less than its melting temperature and the temperature of the resin case is less than the heat resistant lower limit temperature of the resin, and A second step of heating the formic acid gas atmosphere so that the temperature of the formic acid gas atmosphere is equal to or higher than the reduction start temperature of the formic acid;
Subsequent to the first step and the second step, a third step of setting the formic acid gas atmosphere to an inert gas atmosphere having a pressure of atmospheric pressure or higher,
Subsequent to the third step, after the preliminary structure is further heated to raise the temperature so that the solder is in the molten state and the temperature of the resin case is lower than the heat resistant lower limit temperature of the resin, A fourth step of maintaining the temperature of the solder and the temperature of the resin case;
During the execution of the fourth step, a fifth step of evacuating and discharging the inert gas atmosphere and reducing the atmosphere of the preliminary structure to a vacuum state,
Subsequent to the fourth step and the fifth step, the solder in the molten state is cooled and solidified, whereby the first connection terminal, the first connection member, the first connection member, and A sixth step of joining each of the second connection member, the second connection terminal, and the circuit board with the solidified solder;
The manufacturing method of the power converter device characterized by the above-mentioned. Prior to the first step, the circuit board side of the preliminary structure is placed on a pallet and cured on the semiconductor element, the first connection member, and the second connection member of the preliminary structure. Configure the jig assembly by placing the tool,
In the second step, an application degree of the heating amount on the jig side of the jig assembly is increased earlier than an application degree of the heating amount on the pallet side of the jig assembly. The manufacturing method of the power converter device of Claim 1.   3. The solder 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 solder is further heated to the melting temperature or higher. Method of manufacturing the power converter of the present invention.   In the first step, after the formic acid gas atmosphere is evacuated and discharged, and the atmosphere of the preliminary structure is reduced to a vacuum state, the formic acid gas atmosphere is set to a pressure higher than atmospheric pressure. The method for manufacturing a power conversion device according to any one of claims 1 to 3, wherein:   5. The method for manufacturing a power conversion device according to claim 1, wherein the vacuum atmosphere is maintained in the fifth step.   Before the first step, the preliminary structure is placed on a pallet and a jig is mounted on the preliminary structure, and the atmosphere of the jig assembly is in a vacuum state. 6. The method for manufacturing a power conversion device according to claim 1, wherein an inert gas atmosphere filled with an inert gas is used later, and the inert gas atmosphere is evacuated.   7. The method according to claim 1, wherein in the sixth step, after the vacuum atmosphere is changed to an inert gas atmosphere after the fifth step, the molten solder is cooled and solidified. A method for manufacturing the power conversion device according to claim 1.   The method for manufacturing a power converter according to claim 7, wherein the inert gas atmosphere is maintained at atmospheric pressure or higher in the sixth step. The power conversion device further includes a cooler that cools the semiconductor element,
In the preliminary structure, between the connection target surfaces of the first connection terminal and the lead frame connected to the first connection terminal, connection target surfaces of the lead frame and the bus bar connected to the lead frame. Between the connection target surfaces of the circuit board connected to the second connection terminal and the second connection terminal, and between the connection target surfaces of the circuit board and the cooler, 9. The method for manufacturing a power conversion device according to claim 1, wherein solder is disposed correspondingly.

Images