JP2008229709A - Soldering device, soldering method and manufacturing method of electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a soldering device that, when soldering electronic components by high frequency induction heating to a workpiece having a plurality of parts to be soldered, can uniformize the temperature rise speed of an object to be heated even if a workpiece shape has variations and maintains a solder temperature within a prescribed range thereby excellently performs soldering, and also to provide a soldering method and a manufacturing method of electronic equipment. <P>SOLUTION: The soldering device 21 includes a high frequency heating coil 20 and cores 40 which are arranged opposite to a plurality of spindles 17 to be simultaneously heated by high frequency induction heating, which are also disposed movably relatively to the high frequency heating coil 20, and which have magnetic path forming parts 40b installed so as to extend toward the spindles 17. In addition, the soldering device 21 is provided with bolts 50 and nuts 51 for individually positioning and supporting the cores 40. The plurality of cores 40 are positioned and supported using the bolts 50 and the nuts 51 in a state where gaps G between the end face of the magnetic path forming parts 40b and the spindles 17 are adjusted to a value which is set according to the temperature rise speed of the spindles. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a soldering device for soldering an electronic component by melting a solder by heating an object to be heated by high-frequency induction heating to each soldering part of a work having a plurality of soldering parts, and soldering The present invention relates to a method and a method for manufacturing an electronic device.

  When mounting electronic parts such as semiconductor elements, chip resistors, and chip capacitors on a circuit board, a method of joining the circuit board and the electronic parts via solder is common. In addition, conventionally, a metal plate serving as a wiring layer is bonded to the surface of the ceramic substrate and a metal plate serving as a bonding layer is bonded to the back surface, and a semiconductor element is bonded to the metal plate on the front surface side, while the metal on the back surface side is bonded. 2. Description of the Related Art A semiconductor module in which a heat dissipation device (heat sink) that dissipates heat generated by a semiconductor element is joined to a plate to form a module is known. In this type of semiconductor module, a semiconductor element is joined to a metal plate on the front side by soldering.

  Also, a method of soldering a printed circuit board and an electronic component by soldering an electrode of a surface-mounted electronic component to a printed circuit board wired with copper foil is proposed by melting the solder by induction heating (patent) Reference 1). In this method, as shown in FIG. 9, a printed wiring board 73 for forming a wiring circuit made of copper foils 72 and 72a on a printed board 71, a plurality of heat generating elements 74 having conductivity and magnetism, and a holding for holding the same. A jig 76 composed of a plate 75 and an induction heating coil 77 are prepared. The heating element 74 is arranged to face a plurality of electrodes 79 of the surface-mount type electronic component 78 to be soldered. First, the solder 80 is placed on the surfaces of the copper foils 72, 72 a, and the electronic component 78 is arranged so that the electrode 79 of the electronic component 78 is applied to the solder 80. Next, the holding plate 75 is disposed so that the electrode 79 is sandwiched between and in contact with the solder 80 and the heating element 74. Thereafter, the heating element 74 is induction-heated by the induction heating coil 77 to melt the solder 80 by heat conduction.

A material having a high magnetic permeability is used for the heating element 74 corresponding to the electrode 79 of the copper foil 72a having a large heat capacity, and a material having a low permeability is used for the heating element 74 corresponding to the electrode 79 of the copper foil 72 having a small heat capacity. It is disclosed that all the electrodes 79 are soldered at a uniform temperature by using the. Also. The heating element 74 corresponding to the electrode 79 of the copper foil 72a having a large heat capacity is formed with a small size, and the heating element 74 corresponding to the electrode 79 of the copper foil 72 having a small heat capacity is formed with a large size, so that all the electrodes 79 are formed. Is disclosed to be soldered at a uniform temperature.
JP-A-8-293668

  When manufacturing a modularized semiconductor module by joining a heat sink that dissipates heat generated by a semiconductor element to a metal plate on the back side of the ceramic substrate, the ceramic substrate is joined via a metal plate on the metal heat sink. ing. For this reason, the workpiece in a state before the semiconductor element is soldered may have a slightly different shape or a warped state depending on the bonding state or the like. As a result, in the soldering method in which the heating member (object to be heated) is heated by induction heating to melt the solder, the solder is melted at a plurality of soldering portions due to the difference in the distance between the induction heating coil and the heating member. The state becomes different, and depending on the soldering part, the semiconductor element may not be soldered properly. For example, when the same heat generating member is induction-heated, the temperature rising speed of the heat generating member varies depending on the distance from the coil, and as a result, the temperature rising speed of the solder varies.

  In Patent Document 1, when the heat capacities of the copper foils 72 and 72a on the printed circuit board 71 are different, a heating element (heating object) 74 having different permeability and dimensions is used, and all the electrodes 79 are connected regardless of the heat capacity. Soldering is performed at a uniform temperature. However, Patent Document 1 aims to solder each electrode 79 to copper foils 72 and 72a having different heat capacities due to their different sizes from each other at a uniform temperature. In addition, the heating state of the soldering portion, which should be the same, may not be satisfactorily performed due to the temperature rise rate of the heating element 74 being different due to variations in the shape of the workpiece during manufacturing. There is no idea that suggests countermeasures.

  The present invention has been made in view of the above-described conventional problems, and its object is to have variations in the shape of a workpiece when an electronic component is soldered to a workpiece having a plurality of soldering portions by high-frequency induction heating. However, it is possible to provide a soldering apparatus, a soldering method, and a method for manufacturing an electronic device that can uniformize the temperature rise rate of the heating target and can perform soldering satisfactorily while maintaining the solder temperature within a predetermined range. It is in.

  In order to solve the above-mentioned problems, the invention according to claim 1 melts solder by heating an object to be heated by high-frequency induction heating to each soldering part of a work having a plurality of soldering parts. A soldering apparatus for soldering an electronic component, disposed opposite to a high-frequency heating coil capable of passing a high-frequency current and a plurality of heating objects that are simultaneously heated by high-frequency induction heating by the high-frequency heating coil, and A magnetic path forming portion that is arranged to be relatively movable to the high-frequency heating coil and that forms a magnetic path around the high-frequency heating coil by energizing the high-frequency heating coil toward the heating object. An extended core; and positioning means for positioning and supporting the core, wherein the core includes an end surface facing the heating object in the magnetic path forming unit, and the heating object. And positionable supported by said positioning means in a state where the gap was adjusted to the value set in accordance with the rate of temperature increase of the heating object during.

  According to this, even if there is a variation in the shape of the workpiece, by adjusting the gap with the object to be heated by moving the core, the temperature rise of a plurality of objects to be heated simultaneously by the common high-frequency heating coil The speed can be made uniform. Therefore, when the solder is heated and melted at a uniform temperature rise rate by high-frequency induction heating, the solder temperature is maintained within a predetermined range, and the electronic component can be soldered well.

  According to a second aspect of the present invention, in the soldering apparatus according to the first aspect, a plurality of the cores are provided and are individually positioned by the positioning means. According to this invention, each of the plurality of cores can be reliably positioned, and the gap adjusted corresponding to each heating object can be reliably maintained by the positioning means.

  According to a third aspect of the present invention, in the soldering apparatus according to the second aspect, the plurality of cores are arranged to face each of the plurality of heating objects. According to this invention, a plurality of gap values are set due to the presence of a plurality of heating objects. The gap set for each heating object can be maintained by disposing the core opposite to each heating object.

  Invention of Claim 4 is a soldering apparatus as described in any one of Claims 1-3. WHEREIN: The said core straddles the said high frequency heating coil, and a magnetic path formation part from the outer side of a high frequency heating coil Is formed in a lateral C-shaped cross section so as to extend toward the object to be heated. According to this, a magnetic path with high magnetic flux density can be formed between a magnetic path formation part and a heating target object.

  According to a fifth aspect of the present invention, in the soldering apparatus according to any one of the first to third aspects, the soldering apparatus includes a plurality of high-frequency heating coils whose currents flow in opposite directions. And the core separates the high-frequency heating coils in which the current flows in different directions, and a magnetic path forming portion extends toward the object to be heated so that a magnetic path can be formed around each high-frequency heating coil. It is formed in a mold shape.

  According to this, a magnetic path with high magnetic flux density can be formed between a magnetic path formation part and a heating target object. Moreover, it is possible to prevent the magnetic paths formed in the high-frequency heating coil from canceling out due to the magnetic path forming part interposed between the high-frequency heating coils having different current flowing directions.

  The invention according to claim 6 is the soldering apparatus according to any one of claims 1 to 5, wherein the heating object is a heat generating member that can be heated by the high-frequency induction heating, The solder is melted by the heat conducted through the heat generating member, and the gap is set between an end surface of the heat generating member facing the magnetic path forming portion and an end surface of the magnetic path forming portion facing the heat generating member. According to this, heat can be intensively transmitted to the solder by heating the heat generating member by high frequency induction heating to heat the solder.

  A seventh aspect of the present invention is the soldering apparatus according to any one of the first to sixth aspects, wherein the positioning means is interposed between the high-frequency heating coil and the core. It is a spacer. According to this, the gap can be maintained with a simple configuration.

  The invention according to claim 8 is the soldering apparatus according to any one of claims 1 to 6, wherein the positioning means includes a support plate extending from the core, and the support. It consists of bolts and nuts interposed between the plate and the workpiece. According to this, the gap can be maintained with a simple configuration. Further, the gap can be finely adjusted by a simple operation of adjusting the screwing position of the nut with respect to the bolt.

  According to a ninth aspect of the present invention, in the soldering apparatus according to the sixth aspect, the positioning means faces an end surface of the heat generating member facing the magnetic path forming portion and a heat generating member of the magnetic path forming portion. It is a spacer made of a non-magnetic material interposed between the end surface to be made. According to this, the gap can be maintained with a simple configuration.

  The invention according to claim 10 is a soldering method for soldering an electronic component by melting a solder by heating an object to be heated by high-frequency induction heating to each soldering portion of a workpiece having a plurality of soldering portions. A plurality of objects to be heated simultaneously by high-frequency induction heating by a high-frequency heating coil are disposed so as to be relatively movable to the high-frequency heating coil, and the high-frequency heating coil is energized by energization of a high-frequency current. A magnetic path forming portion that forms a magnetic path around the high-frequency heating coil is disposed so as to face a core that extends toward the heating object, and an end face that faces the heating object in the magnetic path forming portion and the heating object The gap between the object and the object is adjusted to a value set according to the temperature rise rate of the object to be heated, and the core is positioned and supported so as to maintain the gap. Cormorant.

  According to this, even if there is a variation in the shape of the workpiece, by adjusting the gap with the object to be heated by moving the core, the temperature rise of a plurality of objects to be heated simultaneously by the common high-frequency heating coil The speed can be made uniform. Therefore, when the solder is heated and melted at a uniform temperature rise rate by high-frequency induction heating, the solder temperature is maintained within a predetermined range, and the electronic component can be soldered well.

  An eleventh aspect of the invention is a method for manufacturing an electronic device using the soldering method according to the tenth aspect in a soldering process. In this invention, in the manufacturing method of an electronic device, there exists an effect | action and effect of the invention as described in the said corresponding claim.

  According to the present invention, when an electronic component is soldered to a workpiece having a plurality of soldering portions by high-frequency induction heating, the temperature rise rate of the heating object is made uniform even if there is a variation in the workpiece shape, etc. Can be kept in a predetermined range and soldering can be performed satisfactorily.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
1 and 2 show a semiconductor module 10 that is a component of an electronic device used in a driving device for a vehicle travel motor. As shown in FIG. 1, the semiconductor module 10 includes a circuit board 11 and a plurality of semiconductor elements 12 as electronic components joined to the circuit board 11 by soldering. The circuit board 11 includes a plurality of ceramic substrates 14 (16 in this embodiment, but only six shown in FIG. 1) having metal circuits 13 on the surface, and are integrated with a metal heat sink 15 via a metal plate 16. The cooling circuit board. Four semiconductor elements 12 are soldered on each ceramic substrate 14 and a total of 64 semiconductor elements 12 on the circuit board 11.

  The semiconductor element 12 is bonded (soldered) to the metal circuit 13. A symbol “H” in FIG. 2 indicates a solder layer. As the semiconductor element 12, for example, an IGBT (Insulated Gate Bipolar Transistor), a MOSFET, or a diode is used. The metal circuit 13 is made of, for example, aluminum or copper. The ceramic substrate 14 is made of, for example, aluminum nitride, alumina, silicon nitride, or the like. The metal plate 16 functions as a bonding layer for bonding the ceramic substrate 14 and the heat sink 15 and is formed of, for example, aluminum or copper.

  The heat sink 15 has a rectangular shape in plan view, and a plurality of (8 in this embodiment, see FIG. 3) ceramic substrates 14 are integrated in the long side direction of the heat sink 15, and two pieces of the ceramic substrate 14 are integrated in the short side direction of the heat sink 15. The ceramic substrate 14 is integrated. Further, the heat sink 15 includes a refrigerant flow path 15a through which a cooling medium flows. The heat sink 15 is formed of aluminum metal, copper, or the like. An aluminum-based metal means aluminum or an aluminum alloy.

  FIG. 3 schematically shows a configuration of a soldering apparatus 21 used for soldering. The soldering device 21 performs a soldering method for melting the solder by high-frequency induction heating and soldering the semiconductor element 12 to the metal circuit 13 as a plurality of soldering portions of the circuit board 11 as a work. It is configured as a device.

  The soldering device 21 includes a chamber 24 that can be sealed. In the soldering device 21, two high-frequency heating coils 20 that form a pair of square pipes are installed at two locations in the upper part of the chamber 24. That is, as shown in FIG. 4, a total of four high-frequency heating coils 20 are installed in the chamber 24. The two high-frequency heating coils 20 that form a pair correspond to each of the ceramic substrates 14 corresponding to a plurality (eight in this embodiment) of ceramic substrates 14 arranged in a line along the long side direction of the heat sink 15. It is disposed on the upper side of the substrate 14. Further, the two high-frequency heating coils 20 forming a pair are different in the direction in which the high-frequency current flows. The high frequency heating coil 20 is electrically connected to a high frequency generator (not shown) included in the soldering device 21.

  And the output of the high frequency generator is controlled based on the measurement result of the temperature sensor (not shown) installed in the chamber 24. The high-frequency heating coil 20 forms a passage for the inside of the square pipe to pass cooling water, and is connected to a cooling water tank (not shown) provided in the soldering device 21. The chamber 24 is provided with a lid 24a that can be opened at a part of the upper side to facilitate maintenance of the high-frequency heating coil 20 and the like, and the lid 24a is always fixed in an airtight state at a closed position. .

  As shown in FIG. 3, the soldering device 21 is connected to a reducing gas supply unit 30 for supplying a reducing gas (hydrogen in this embodiment) into the chamber 24. The reducing gas supply unit 30 includes a pipe 30a, an opening / closing valve 30b of the pipe 30a, and a hydrogen tank 30c. The soldering device 21 is connected to an inert gas supply unit 31 for supplying an inert gas (nitrogen in this embodiment) into the chamber 24. The inert gas supply unit 31 includes a pipe 31a, an opening / closing valve 31b of the pipe 31a, and a nitrogen tank 31c. The soldering device 21 is connected to a gas discharge part 32 for discharging the gas filled in the chamber 24 to the outside. The gas discharge unit 32 includes a pipe 32a, an opening / closing valve 32b of the pipe 32a, and a vacuum pump 32c. The soldering device 21 includes a reducing gas supply unit 30, an inert gas supply unit 31, and a gas discharge unit 32 so that the pressure in the chamber 24 can be adjusted. Pressurized or depressurized by pressure adjustment.

  The soldering device 21 is connected to a heat medium supply unit 33 as a supply means for supplying a heat medium (cooling gas) into the chamber 24 after soldering. The heat medium supply unit 33 includes a pipe 33a, an opening / closing valve 33b of the pipe 33a, and a gas tank 33c. The heat medium supply unit 33 is connected to supply a cooling gas to the heat sink 15 of the semiconductor module 10 accommodated in the chamber 24. Note that the heat medium supplied from the heat medium supply unit 33 may be a coolant.

  In the manufacturing method of the semiconductor module 10 using the soldering apparatus 21, when the semiconductor element 12 is soldered on the circuit board 11, the soldering is melted by high-frequency induction heating, but the solder is melted directly by high-frequency induction heating. I don't let it. That is, the soldering uses a heat generating member (heating object) that can be heated by high frequency induction heating, and the heat generated by the heat generating member is conducted to the solder and melted. In this embodiment, a weight is used as the heat generating member, and a positioning jig is used. As shown in FIG. 4, the weight 17 includes a convex portion having a pressure surface 17 a that contacts the semiconductor element 12 or the metal circuit 13 during soldering. Further, the weight 17 is formed in a rectangular shape in plan view, and two concave portions 17b are formed on the upper surface. The jig 18 is used to position the sheet solder 19, the semiconductor element 12, and the weight 17 on the ceramic substrate 14 during soldering. For this reason, the jig 18 is formed with a positioning hole 18a.

  The weight 17 is formed using a material that can be heated by high-frequency induction heating. When a high-frequency current is supplied to the high-frequency heating coil 20, a current is generated by a change in magnetic flux passing through the weight 17, and its own electricity is generated. Heat is generated by resistance. The weight 17 of this embodiment is made of stainless steel. The jig 18 is made of, for example, a material such as graphite or ceramics.

  As shown in FIGS. 3 and 4, in the soldering device 21, a plurality of cores 40 are disposed on the upper side of the two high-frequency heating coils 20 to be paired in the extending direction of the high-frequency heating coils 20. . The cores 40 are arranged so as to face one ceramic substrate 14, specifically, one weight 17. The core 40 is made of a material having high magnetic permeability such as ferrite or electromagnetic steel plate. The plurality of cores 40 all have the same magnetic characteristics, and have the same weight and dimensions.

  The core 40 is formed in a rectangular shape in plan view, and the cross-sectional view along the length direction of the core 40 is formed in a horizontal E shape. As shown in FIG. 4, the core 40 is formed with two housing recesses 40a that open downward, and the high-frequency heating coil 20 is housed in each housing recess 40a. Therefore, the core 40 is arrange | positioned on the two high frequency heating coils 20 so that the two high frequency heating coils 20 used as a pair may be straddled.

  In the core 40, magnetic path forming portions 40 b extending toward the weight 17 are formed at positions on both sides of the housing recesses 40 a so as to sandwich the housing recesses 40 a and outside the high-frequency heating coils 20. . That is, the core 40 is provided with three magnetic path forming portions 40b. When a high frequency current is passed through the high frequency heating coil 20, a magnetic path is formed around the high frequency heating coil 20 so as to pass through the core 40 and the weight 17 by the magnetic path forming portion 40 b. In the state where the core 40 is disposed opposite to the weight 17, the accommodation recess 40 a is disposed opposite to the recess 17 b of the weight 17, and each magnetic path forming portion 40 b is disposed opposite to the portion other than the recess 17 b in the weight 17. It is like that.

  Support plates 41 extending from the core 40 are integrated with both ends of the core 40 in the length direction. Both support plates 41 are formed with insertion holes 41a. Further, the bolt 50 can be inserted into each insertion hole 41a. A nut 51 is screwed onto the bolt 50, and the nut 51 is disposed below the support plate 41. The bolt 50 is erected on the heat sink 15, and the height of the core 40 supported by the nut 51 from the heat sink 15 can be adjusted by adjusting the screwing position of the nut 51 to the bolt 50. Yes. That is, the support plate 41, the bolt 50, and the nut 51 are provided for each core 40, and form positioning means for positioning and supporting each core 40 individually at a predetermined height. The bolt 50 and the nut 51 are provided with the support plate 41. A spacer interposed between the heat sink 15 and the heat sink 15 is formed. The core 40 can be moved relative to the high-frequency heating coil 20 by changing the screwing position of the nut 51 to the bolt 50.

  Next, a method for soldering the semiconductor element 12, which is one step of the method for manufacturing the semiconductor module 10 that is a component of the electronic device, using the soldering apparatus 21 configured as described above will be described. In addition, the thing (henceforth a "soldering object") which joined the heat sink 15 to the circuit board 11 is produced previously.

  When soldering, an object to be soldered is placed in the chamber 24 and positioned. Next, a jig 18 is placed on each circuit board 11 (ceramic substrate 14) to be soldered, and the sheet solder 19 and the semiconductor element 12 are placed in each hole 18a of the jig 18. The sheet solder 19 is disposed between the circuit board 11 (metal circuit 13) and the semiconductor element 12. Then, a weight 17 is placed on the circuit board 11 on which the semiconductor element 12 is arranged. In this state, the sheet solder 19, the semiconductor element 12, and the weight 17 are laminated on the circuit board 11 (metal circuit 13) in this order from the metal circuit 13 side. The sheet solder 19, the semiconductor element 12, and the weight 17 are stacked in the vertical direction of the soldering device 21. Further, the pressing surface 17 a of the weight 17 is in contact with the non-bonding surface of the semiconductor element 12 and pressurizes it.

  Next, the screwing position of the nut 51 with respect to the bolt 50 is adjusted, and the height of the nut 51 from the heat sink 15 is adjusted. Here, in the row of weights 17 arranged in a line along the length direction of the heat sink 15, when all the weights 17 are arranged in parallel at the same height, the weight 17 located at the center of the row is Since the weights 17 are also located on both sides, the weight 17 located in the center receives the heat from the weights 17 on both sides when heated by the high-frequency heating coil 20, and becomes the highest temperature. On the other hand, in the row of weights 17, the weights 17 located at both ends of the row have the weights 17 only on one side. For this reason, since the heat received from the adjacent weight 17 is less than that of the weight 17 located in the center and heat can be radiated to the side, the weights 17 located at both ends are heated by the high-frequency heating coil 20. When the temperature is lower than the weight 17 located at the center. Therefore, when all the weights 17 are set to the same height, when all the weights 17 are heated at the same time, in the row of weights 17, the rate of temperature rise of the weights 17 decreases from the center toward both ends. The temperature of 17 is also lowered.

  Further, the heat sink 15 has a variation in shape (thickness) compared to the ceramic substrate 14 or the like, or even when the ceramic substrate 14 is joined to the heat sink 15 via the metal plate 16 even when the thickness is constant, Warpage may occur. For this reason, for example, when the heat sink 15 has a variation in shape, the distance from the upper surface of the heat sink 15 to the high-frequency heating coil 20 varies depending on the position, and the distance between the high-frequency heating coil 20 and the weight 17 is different in different metal circuits 13. It will be in a different state. As a result, when the weight 17 having the same temperature raising performance is used, even if the high-frequency current supplied to the high-frequency heating coil 20 is constant, the temperature rise rate (heat generation state) of the weight 17 is different.

  Then, in the soldering device 21, in consideration of the difference in the shape of the heat sink 15 and the temperature rise rate due to the position of the weight 17, each core 40, The gap G with the weight 17 disposed to face the core 40 is adjusted. The gap G is the distance between the end surface (lower end surface) facing the weight 17 in the magnetic path forming portion 40b and the end surface (upper end surface) facing the magnetic path forming portion 40b in the weight 17.

  In this embodiment, in the array of cores 40 arranged in a line along the length direction of the heat sink 15, the core 40 located at the center of the array is farthest from the weight 17 to maximize the gap G, and both ends of the array The core 40 is gradually brought closer to the weight 17 as it goes to, and the gap G is gradually reduced. That is, the distance between the end face of each core 40 facing the weight 17 of the magnetic path forming portion 40b and the end face of the weight 17 facing the magnetic path forming portion 40b is set according to the temperature rise rate of the weight 17. Set the value to Then, the screwing position of the nut 51 is adjusted so that the individual gap G set between each core 40 and the weight 17 is maintained, and the core 40 is individually determined using the bolt 50 and the nut 51. Positioned and supported at the position.

  Next, the gas exhaust unit 32 is operated to evacuate the chamber 24, and the inert gas supply unit 31 is operated to supply nitrogen into the chamber 24, thereby filling the chamber 24 with the inert gas. After this evacuation and supply of nitrogen are repeated several times, the reducing gas supply unit 30 is operated to supply hydrogen into the chamber 24, and the inside of the chamber 24 is set to a reducing gas atmosphere.

  Next, the high frequency generator is operated, and a high frequency current is passed through the high frequency heating coil 20. Then, a magnetic path is formed around the high-frequency heating coil 20 through the magnetic path forming part 40b and through the opposing weight 17 to generate a high-frequency magnetic flux, and an eddy current is generated in the weight 17 due to the passage of the magnetic flux. appear. At this time, since the end surface of the magnetic path forming portion 40b faces and approaches the weight 17, a magnetic path having a high magnetic flux density is formed. A weight (object to be heated) 17 placed in the magnetic flux of the high-frequency heating coil 20 is heated by electromagnetic induction, and the heat is transmitted from the pressure surface 17 a of the weight 17 to the semiconductor element 12. Then, on the sheet solder 19 placed on each metal circuit 13 of the circuit board 11, heat generated in the weight 17 is concentrated (locally) via the pressure surface 17 a of the weight 17 and the semiconductor element 12. It is transmitted and heated. As a result, the sheet solder 19 is melted by being heated to a temperature equal to or higher than the melting temperature by the heat transmitted through the semiconductor element 12.

  In the soldering device 21, one core 40 is disposed opposite to one weight 17, and the gap G between the core 40 and the weight 17 is adjusted to perform soldering by high frequency induction heating. Then, considering the variation and warpage of the shape of the heat sink 15, and further considering the variation of the temperature rise rate (heat generation state) due to the positions of the weights 17 arranged in parallel, the gap G between the core 40 and the weight 17 A value is set. For this reason, if the high-frequency current supplied to the high-frequency heating coil 20 is constant, the temperature rising speeds of the plurality of weights 17 are made uniform, and the sheet solders 19 are all heated at the same temperature. Therefore, all the sheet solders 19 are melted at the same timing by keeping the temperature within a predetermined range, and it is possible to prevent the melted states of the solder from being different in a plurality of soldering portions.

  In addition, since the semiconductor element 12 is pressed toward the circuit board 11 by the weight 17, it is not moved by the surface tension of the molten solder. Then, after the sheet solder 19 is completely melted, the supply of the high-frequency current to the high-frequency heating coil 20 is stopped. Note that the high-frequency current supply time is set to an appropriate time by a test in advance. Further, the pressure in the chamber 24 is increased and decreased according to the progress of the soldering operation, and the atmosphere is adjusted.

  After stopping the supply of current to the high-frequency heating coil 20, the cooling medium is supplied to the chamber 24 by operating the cooling heat medium supply unit 33. The cooling gas is blown toward the inlet or outlet of the refrigerant flow path 15a of the heat sink 15, and the cooling gas supplied into the chamber 24 flows around the refrigerant flow path 15a and the heat sink 15 to be soldered. The object (semiconductor module 10) is cooled. As a result, the molten solder is solidified by being cooled below the melting temperature, and joins the metal circuit 13 and the semiconductor element 12. In this state, the soldering is finished, and the semiconductor module 10 is completed.

According to the above embodiment, the following effects can be obtained.
(1) In the soldering device 21, a plurality of cores 40 are provided on the high-frequency heating coil 20, and the cores 40 are arranged to face each other with a plurality of weights 17 that are simultaneously heated by high-frequency induction heating by the high-frequency heating coil 20. did. The core 40 can be moved relative to the high-frequency heating coil 20, and can be positioned and supported using the bolt 50 and the nut 51 in a state where the gap G between the core 40 and the weight 17 is adjusted. Therefore, the weight 17 can be heated by adjusting the gap G so that the temperature rising speeds of the plurality of weights 17 heated at the same time are made uniform. Accordingly, the temperature rise rate of the sheet solder 19 is made uniform, and the semiconductor element 12 can be soldered in a state where the solder temperature is kept uniformly within a predetermined range, and the soldering can be performed satisfactorily.

  (2) A plurality of cores 40 are disposed on the high-frequency heating coil 20, and the plurality of weights 17 are simultaneously heated by the high-frequency heating coil 20. The plurality of weights 17 are arranged in a row in the length direction of the heat sink 15, and the center of the row of the weights 17 is easily heated. Further, the heat sink 15 has variations in shape such as warpage. In the soldering apparatus 21, there are various conditions in soldering. However, the temperature rise rate of the weight 17 is made uniform only by adjusting the gap G in consideration of each condition, and soldering is performed in all the soldering portions. It can be done well. Therefore, in order to make the temperature rise rate of all the weights 17 uniform, there is no need to prepare or select a heating element having different magnetic permeability or heat capacity as in the background art, and the soldering operation is facilitated. Can do.

  (3) By heating the weight 17 that presses the semiconductor element 12 to heat the sheet solder 19, heat can be intensively transmitted to the sheet solder 19. Since the gap G between the weight 17 and the core 40 can be adjusted, soldering can be performed more satisfactorily.

  (4) The core 40 includes three magnetic path forming portions 40 b extending toward the weight 17. Further, two concave portions 17b are formed on the surface of the weight 17 facing the core 40. And each magnetic path formation part 40b is opposingly arranged by parts other than the recessed part 17b in the weight 17. FIG. For this reason, for example, a magnetic path having a high magnetic flux density can be formed between the core 40 and the weight 17 as compared with a core in which the magnetic path forming portion 40b is not formed and the magnetic path is an open loop. The weight 17 can be efficiently heated by high-frequency induction heating, and the power required to form a magnetic path having a predetermined magnetic flux density can be suppressed.

  (5) The core 40 is formed in an E-shaped cross section, and a magnetic path forming part 40b is interposed between the two high-frequency heating coils 20. For this reason, it is possible to prevent the magnetic paths formed around each high-frequency heating coil 20 from canceling each other.

  (6) Fine adjustment of the height of the core 40 can be easily performed only by a simple operation such as screwing or unscrewing the nut 51 with respect to the bolt 50. That is, fine adjustment of the gap G between the weight 17 and the core 40 can be easily performed. Therefore, compared with the case where a large number of heating elements having different magnetic permeability and heat capacity are required as in the background art, the work for making the temperature rise rate uniform can be facilitated.

  (7) Soldering is performed by the above-described method in the soldering process of the semiconductor element 12 which is one process of the manufacturing method of the semiconductor module 10 which is a component of the electronic device. Therefore, each effect described above can be obtained in the method for manufacturing an electronic device.

  (8) The soldering apparatus 21 includes a plurality of cores 40, and each core 40 can be individually positioned using a bolt 50 and a nut 51. For this reason, the gap G set for each core 40 can be accurately maintained at the set value.

  (9) In the soldering device 21, the plurality of cores 40 are arranged to face each weight 17. For this reason, the gap G set with respect to each of the plurality of weights 17 can be maintained, and the temperature rising speed of the plurality of weights 17 can be made uniform evenly.

In addition, you may change the said embodiment as follows.
As shown in FIG. 5, the core 60 may be formed in a lateral C shape in a sectional view along the length direction. The core 60 has an accommodation recess 60a that opens downward, and magnetic path forming portions 60b are formed on both sides of the accommodation recess 60a. Further, a support plate 60 c is extended from the core 60. And the two high frequency heating coils 20 used as a pair are accommodated in the accommodation recessed part 60a. In these two high-frequency heating coils 20, the direction of current flow is the same. Further, the weight 17 disposed to face the core 60 is formed with only one concave portion 17 b on the surface facing the core 60. The accommodating recess 60a is disposed opposite to the recess 17b, and the end surface of the magnetic path forming portion 60b facing the weight 17 is disposed opposite to the end surface of the weight 17 facing the core 60.

  As shown in FIG. 6, the positioning means of the core 40 may be a spacer 61 interposed between the upper surface of each high-frequency heating coil 20 and the inner surface of the housing recess 40a of the core 40. In this case, the support plate 41 in the core 40 is deleted, and the bolt 50 and the nut 51 are not used. In addition, you may use the spacer 61 interposed between the upper surface of each high frequency heating coil 20, and the inner surface of the accommodation recessed part 60a of the core 60 as a positioning means of the core 60 shown in FIG.

  As shown in FIG. 7, the positioning means of the core 40 is a spacer interposed between the end face of the magnetic path forming portion 40b facing the weight 17 and the end face of the weight 17 facing the magnetic path forming portion 40b. 62 may be sufficient. The spacer 62 is made of a nonmagnetic material such as ceramic or glass. In this case, the support plate 41 in the core 40 is deleted, and the bolt 50 and the nut 51 are not used. As a positioning means for the core 60 shown in FIG. 5, a spacer 62 interposed between the end surface of the magnetic path forming portion 60b facing the weight 17 and the end surface of the weight 17 facing the magnetic path forming portion 60b. There may be.

  As shown in FIG. 8, the core 63 may be a plate that is interposed between two high-frequency heating coils 20 that form a pair. The core 63 itself forms a magnetic path forming part. The positioning means for the core 63 includes a spacer 64 interposed between an end surface of the core 63 facing the weight 17 and an end surface of the weight 17 facing the core 63. In this case, the current flows in the two high-frequency heating coils 20 in opposite directions.

  The cores 40 and 60 may be supported by being suspended from the lid portion 24a, and the lid portion 24a is provided with a suspension portion for suspending the cores 40 and 60. And you may adjust the gap G of the weight 17 and the cores 40 and 60 by adjusting the suspension position of the cores 40 and 60 with respect to a suspension part. In this case, the hanging portion constitutes a positioning means for the cores 40 and 60.

A plurality of weights 17 having different temperature rising characteristics may be used, or weights 17 having at least one of dimensions, width, and heat capacity may be used.
The number of ceramic substrates 14 bonded on the circuit board 11 may be plural, and may be arbitrarily changed. Further, the number of semiconductor elements 12 to be soldered on one metal circuit 13 may be arbitrarily changed.

  The circuit board 11 is not limited to a board with a heat sink provided with the heat sink 15, and may be any circuit board having a plurality of soldering portions. For example, a configuration in which a plurality of metal circuits 13 are formed on one side of a ceramic substrate 14 or a configuration in which a plurality of metal circuits 13 are formed on one side of a resin substrate may be adopted. As the resin constituting the resin substrate, a resin having particularly excellent heat resistance such as polyimide and polyamideimide is preferable. However, since high heat resistance is required for a short time during soldering, such as an epoxy resin. Alternatively, a resin having lower heat resistance than polyimide may be used. In the case of a resin substrate, one reinforced with glass fiber or carbon fiber is preferable.

○ The solder used for soldering is not limited to the sheet solder 19, and a solder paste may be used.
The high frequency heating coil 20 may be formed in a cylinder instead of a square pipe.

  The semiconductor element 12 may be soldered to the metal circuit 13 by directly heating and melting the sheet solder 19 by high-frequency induction heating by the high-frequency heating coil 20 without using the weight 17 and the jig 18. In this case, the sheet solder 19 itself becomes an object to be heated that is heated by high-frequency induction heating by the high-frequency heating coil 20. Even with this configuration, the sheet solder 19 can be heated by adjusting the gap G so that the temperature rising speeds of the plurality of sheet solders 19 that are simultaneously heated are made uniform. Accordingly, the temperature rise rate of the sheet solder 19 is made uniform, and the semiconductor element 12 can be soldered in a state where the solder temperature is kept uniformly within a predetermined range, and the soldering can be performed satisfactorily.

  In the configuration in which the weight 17 is heated by high-frequency induction heating and the solder is melted by the heat, the weight 17 is not limited to stainless steel but may be any material that can be induction-heated. For example, instead of stainless steel, iron or graphite Or may be configured using two kinds of conductive materials having different thermal conductivities.

  (Circle) the cores 40 and 60 may be formed in the magnitude | size which can accommodate two pairs of the two high frequency heating coils 20 used as the pair with the accommodation recessed parts 40a and 60a. In this case, a partition is provided between the two high-frequency heating coils 20 that form a pair.

In the soldering device 21, the number of the high-frequency heating coils 20 may be arbitrarily changed according to the number of soldering portions to be soldered by high-frequency induction heating.
Only one high-frequency heating coil 20 may be provided in the chamber 24. In this case, the core has a C-shaped section (for example, the core 60 shown in FIG. ) Is used.

  An electronic component that is joined by soldering to the metal circuit 13 of the circuit board 11 that constitutes the semiconductor module 10 is not limited to the semiconductor element 12, and the semiconductor element 12 and other electronic components such as a chip resistor and a chip capacitor are mixed. May be.

  In the soldering device 21, the size is not limited to the configuration in which the cores 40, 60, and 63 are disposed to face the weights 17, but the cores 40, 60, and 63 extend over a plurality of (for example, two) weights 17. The cores 40, 60, 63 may be arranged opposite to each other so as to straddle the plurality of weights 17.

The top view which shows the semiconductor module of embodiment. The expanded sectional view in the AA line of Drawing 1 in the semiconductor module of an embodiment. Sectional drawing which shows schematically the soldering apparatus of embodiment. Sectional drawing which expands and shows a part of soldering apparatus of embodiment. The expanded sectional view which shows another example of a core. The expanded sectional view which shows another example of a positioning means. The expanded sectional view which shows another example of a positioning means. The expanded sectional view which shows another example of a core and a positioning means. Sectional drawing which shows background art.

Explanation of symbols

  G ... Gap, 11 ... Circuit board as work, 12 ... Semiconductor element as electronic component, 13 ... Metal circuit as soldering part, 17 ... Weight as heating object and heating member, 19 ... As heating object Sheet solder, 20 ... high frequency heating coil, 21 ... soldering device, 40, 60, 63 ... core, 40b, 60b ... magnetic path forming portion, 41, 60c ... support plate for forming positioning means, 50 ... forming positioning means Bolts 51, nuts forming positioning means 61, 62, 64, spacers as positioning means;

Claims (11)

A soldering device for soldering an electronic component by melting a solder by heating an object to be heated by high-frequency induction heating to each soldering part of a work having a plurality of soldering parts,
A high-frequency heating coil capable of passing a high-frequency current;
A plurality of objects to be heated that are simultaneously heated by high-frequency induction heating by the high-frequency heating coil, and disposed so as to be relatively movable to the high-frequency heating coil, and by applying a high-frequency current to the high-frequency heating coil A core in which a magnetic path forming part for forming a magnetic path around the high-frequency heating coil is extended toward the heating object;
Positioning means for positioning and supporting the core,
The core is positioned in a state in which a gap between an end surface of the magnetic path forming unit facing the heating object and the heating object is adjusted to a value set according to a temperature increase rate of the heating object. Soldering device that can be positioned and supported by means.   The soldering apparatus according to claim 1, wherein a plurality of the cores are provided and are individually positioned by the positioning unit.   The soldering device according to claim 2, wherein the plurality of cores are arranged to face each of the plurality of heating objects.   The core is formed in a transverse C-shaped cross section so that the core crosses the high-frequency heating coil and a magnetic path forming portion extends from the outside of the high-frequency heating coil toward the object to be heated. The soldering apparatus according to claim 1.   The soldering apparatus includes a plurality of high-frequency heating coils whose currents flow in opposite directions, and the core partitions the high-frequency heating coils having different current-flow directions and forms a magnetic path around each high-frequency heating coil. The soldering apparatus according to any one of claims 1 to 3, wherein the magnetic path forming part is formed in a cross-sectional lateral E shape extending toward the heating object so as to be possible.   The heating object is a heat generating member that can be heated by the high-frequency induction heating, the solder is melted by heat conducted through the heat generating member, and the gap has an end surface facing the magnetic path forming portion in the heat generating member; The soldering device according to any one of claims 1 to 5, wherein the soldering device is set between an end face of the magnetic path forming portion facing the heat generating member.   The soldering apparatus according to any one of claims 1 to 6, wherein the positioning unit is a spacer interposed between the high-frequency heating coil and the core.   The said positioning means consists of the volt | bolt and nut which are interposed between the support plate extended from the said core, and the said support plate and a workpiece | work. Soldering device.   The positioning means is a spacer made of a non-magnetic material interposed between an end face of the heat generating member facing the magnetic path forming portion and an end face of the magnetic path forming portion facing the heat generating member. 6. The soldering apparatus according to 6. A soldering method for soldering an electronic component by melting a solder by heating an object to be heated by high frequency induction heating to each soldering part of a work having a plurality of soldering parts,
A plurality of objects to be heated simultaneously by high-frequency induction heating by a high-frequency heating coil are disposed so as to be relatively movable to the high-frequency heating coil, and the high-frequency heating coil is energized by applying a high-frequency current to the high-frequency heating coil. A magnetic path forming portion that forms a magnetic path around the core extended toward the object to be heated is disposed oppositely,
Adjusting the gap between the end surface facing the heating object in the magnetic path forming unit and the heating object to a value set according to the temperature increase rate of the heating object;
A soldering method comprising performing soldering while positioning and supporting the core so as to maintain the gap.   The manufacturing method of the electronic device which uses the soldering method of Claim 10 for a soldering process.

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