JP7026451B2 - Power semiconductor modules, their manufacturing methods, and power converters - Google Patents

Description

The present invention relates to a power semiconductor module, a method for manufacturing the same, and a power conversion device.

Japanese Patent Application Laid-Open No. 10-50758 (Patent Document 1) discloses a power semiconductor module including a ceramic substrate, a transistor, a diode, and a tin-plated copper lead. The ceramic substrate includes a metal plate that functions as a heat sink, a ceramic insulating plate provided on the metal plate, and a metal wiring pattern formed on the ceramic insulating plate and plated with nickel. The lead connects the transistor to the metal wiring pattern and the diode to the metal wiring pattern. The ceramic substrate is preheated to 200 ° C. and then the leads are joined to the metal wiring pattern by ultrasonic joining.

Japanese Unexamined Patent Publication No. 10-50758

Since the power semiconductor module disclosed in Patent Document 1 includes a ceramic insulating plate, the cost of the power semiconductor module is high. In order to reduce the cost of the power semiconductor module, it is conceivable to use an insulating substrate including an insulating resin sheet as the substrate of the power semiconductor module.

However, the insulating resin sheet has lower hardness and lower heat resistance than the ceramic insulating plate. Further, in the power semiconductor module disclosed in Patent Document 1, when a tin-plated copper lead is joined to a nickel-plated metal wiring pattern by an ultrasonic joining method, the tin becomes a lead. The copper leads are directly bonded to the nickel-plated metal wiring pattern as they are ejected from the bonding interface with the metal wiring pattern. Therefore, the insulating resin sheet contained in the insulating substrate is thermally and mechanically damaged by the heat and mechanical stress generated when the leads are joined to the metal wiring pattern by the ultrasonic joining method. Therefore, the power semiconductor module has low reliability.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a power semiconductor module having high cost and high reliability and a method for manufacturing the same. An object of the present invention is to provide a power conversion device having low cost and high reliability.

The power semiconductor module of the present invention includes an insulating substrate, a power semiconductor element, and an electrode terminal. The insulating substrate includes an insulating resin sheet and a conductive circuit pattern provided on the first surface of the insulating resin sheet. The power semiconductor element is bonded to the conductive circuit pattern via the conductive bonding member. The electrode terminals are ultrasonically bonded to the conductive circuit pattern via a cushioning member. The electrode terminal has a first main surface facing the cushioning member and a second main surface opposite to the first main surface. The cushioning member consists of a conductive circuit pattern and a material having a lower yield strength and a lower melting point than the electrode terminals. The electrode terminals are separated from the conductive circuit pattern.

The method for manufacturing a power semiconductor module of the present invention comprises joining a power semiconductor element to a conductive circuit pattern via a conductive joining member. The insulating substrate includes an insulating resin sheet and a conductive circuit pattern provided on the first surface of the insulating resin sheet. The method for manufacturing a power semiconductor module of the present invention further comprises joining electrode terminals to a conductive circuit pattern via a shock absorber. The electrode terminal has a first main surface facing the cushioning member and a second main surface opposite to the first main surface. The cushioning member consists of a conductive circuit pattern and a material having a lower yield strength and a lower melting point than the electrode terminals. Joining the electrode terminals to the conductive circuit pattern via the cushioning member means stacking the cushioning members on the conductive circuit pattern, stacking the electrode terminals on the cushioning member, and placing the ultrasonic horn on the second main surface. It includes ultrasonically joining the electrode terminal and the cushioning member by pressing them together, and joining the cushioning member and the conductive circuit pattern. By pressing the ultrasonic horn against the second main surface, the buffer member undergoes a phase transition from the solid phase to the liquid phase. The electrode terminals are separated from the conductive circuit pattern.

The power conversion device of the present invention has the power semiconductor module of the present invention, and outputs a main conversion circuit that converts and outputs the input power and a control signal that controls the main conversion circuit to the main conversion circuit. It is equipped with a control circuit.

The power semiconductor module of the present invention includes an insulating substrate including an insulating resin sheet. Therefore, the cost of the power semiconductor module of the present invention is reduced. Further, in the power semiconductor module of the present invention, the electrode terminals are ultrasonically bonded to the conductive circuit pattern via the cushioning member and separated from the conductive circuit pattern. The cushioning member consists of a conductive circuit pattern and a material having a lower yield strength and a lower melting point than the electrode terminals. The cushioning member can prevent the insulating resin sheet from being thermally and mechanically damaged by the heat and mechanical stress generated when the electrode terminals are ultrasonically bonded to the conductive circuit pattern. The power semiconductor module of the present invention has high reliability.

In the method for manufacturing a power semiconductor module of the present invention, the insulating substrate includes an insulating resin sheet. Therefore, the cost of the power semiconductor module is reduced. Further, in the method of manufacturing a power semiconductor module of the present invention, bonding an electrode terminal to a conductive circuit pattern via a cushioning member causes an ultrasonic horn to be pressed against a second main surface to bond the electrode terminal and the cushioning member. It includes ultrasonic bonding and bonding a cushioning member and a conductive circuit pattern. The cushioning member consists of a conductive circuit pattern and a material having a lower yield strength and a lower melting point than the electrode terminals. By pressing the ultrasonic horn against the second main surface, the buffer member undergoes a phase transition from the solid phase to the liquid phase. The electrode terminals are separated from the conductive circuit pattern. The cushioning member can prevent the insulating resin sheet from being thermally and mechanically damaged by the heat and mechanical stress generated when the electrode terminals are ultrasonically bonded to the conductive circuit pattern. According to the method for manufacturing a power semiconductor module of the present invention, a power semiconductor module having high reliability can be obtained.

The power conversion device of the present invention includes a main conversion circuit having the power semiconductor module of the present invention. The power conversion device of the present invention has low cost and high reliability.

It is a schematic sectional drawing of the power semiconductor module which concerns on Embodiment 1 of this invention. It is a schematic partial enlarged sectional view of the region II shown in FIG. 1 of the power semiconductor module which concerns on Embodiment 1 of this invention. It is a schematic partial enlarged plan view of the power semiconductor module which concerns on Embodiment 1 of this invention. It is a figure which shows the flowchart of the manufacturing method of the power semiconductor module which concerns on Embodiment 1 of this invention. It is a schematic partial enlarged sectional view which shows one step of the manufacturing method of the power semiconductor module which concerns on Embodiment 1 of this invention. It is a schematic partial enlarged sectional view which shows the next process of the process shown in FIG. 5 in the manufacturing method of the power semiconductor module which concerns on Embodiment 1 of this invention. It is a schematic partial enlarged sectional view which shows the next process of the process shown in FIG. 6 in the manufacturing method of the power semiconductor module which concerns on Embodiment 1 of this invention. It is a schematic partial enlarged sectional view which shows one process of the manufacturing method of the power semiconductor module of the comparative example. It is a schematic partial enlarged sectional view of the power semiconductor module which concerns on Embodiment 2 of this invention. It is a schematic partial enlarged sectional view which shows one step of the manufacturing method of the power semiconductor module which concerns on Embodiment 2 of this invention. It is a schematic partial enlarged sectional view which shows the next process of the process shown in FIG. 10 in the manufacturing method of the power semiconductor module which concerns on Embodiment 2 of this invention. It is a schematic partial enlarged sectional view which shows the next process of the process shown in FIG. 11 in the manufacturing method of the power semiconductor module which concerns on Embodiment 2 of this invention. It is a schematic partial enlarged sectional view of the power semiconductor module which concerns on Embodiment 3 of this invention. It is a schematic partial enlarged plan view of the power semiconductor module which concerns on Embodiment 3 of this invention. It is a schematic partial enlarged sectional view of the power semiconductor module which concerns on the modification of Embodiment 3 of this invention. It is a schematic partial enlarged sectional view of the power semiconductor module which concerns on the modification of Embodiment 3 of this invention. It is a schematic partial enlarged sectional view which shows one step of the manufacturing method of the power semiconductor module which concerns on Embodiment 3 of this invention. It is a schematic partial enlarged sectional view which shows the next process of the process shown in FIG. 17 in the manufacturing method of the power semiconductor module which concerns on Embodiment 3 of this invention. It is a schematic partial enlarged sectional view which shows the next process of the process shown in FIG. 18 in the manufacturing method of the power semiconductor module which concerns on Embodiment 3 of this invention. It is a block diagram which shows the structure of the power conversion system which concerns on Embodiment 4 of this invention.

Hereinafter, embodiments of the present invention will be described. The same reference number is assigned to the same configuration, and the description thereof will not be repeated.

Embodiment 1.
The power semiconductor module 1 according to the first embodiment will be described with reference to FIGS. 1 to 3. The power semiconductor module 1 of the present embodiment mainly includes an insulating substrate 11, a power semiconductor element (40, 45), and an electrode terminal 20. The power semiconductor module 1 of the present embodiment may further include a sealing member 67. The power semiconductor module 1 of the present embodiment may further include a case 65.

The insulating substrate 11 includes an insulating resin sheet 13 and a conductive circuit pattern 14 provided on the first surface 13a of the insulating resin sheet 13. The insulating resin sheet 13 is not particularly limited, but may be formed of an epoxy resin. The insulating resin sheet 13 is not particularly limited, but may be formed of a material having a glass transition temperature of 100 ° C. or higher and 130 ° C. or lower. The insulating resin sheet 13 may be thinner than the conductive circuit pattern 14. The insulating resin sheet 13 is not particularly limited, but may have a thickness t ₁ of 0.1 mm or more and 0.25 mm or less.

The conductive circuit pattern 14 may be made of copper or aluminum. The conductive circuit pattern 14 may be thicker than the insulating resin sheet 13. The conductive circuit pattern 14 may be thinner than the electrode terminal 20. The conductive circuit pattern 14 is not particularly limited, but may have a thickness t ₂ of 0.3 mm or more and 1.0 mm or less.

The insulating substrate 11 may further include a heat radiating member 12 on the second surface 13b of the insulating resin sheet 13 on the side opposite to the first surface 13a of the insulating resin sheet 13. The heat radiating member 12 is not particularly limited, but may be a metal plate such as a copper plate. The heat radiating member 12 may be thicker than the insulating resin sheet 13 and the conductive circuit pattern 14. The heat radiating member 12 is not particularly limited, but may have a thickness t ₅ of 1.1 mm or more and 5.0 mm or less.

The power semiconductor device (40, 45) is not particularly limited, but may include a switching element 40 and a freewheeling diode 45 connected in antiparallel to the switching element 40. The switching element 40 may be, for example, an insulated gate bipolar transistor (IGBT) or a metal oxide semiconductor field effect transistor (PWM). The power semiconductor device (40, 45) may be formed from a semiconductor material such as silicon (Si), silicon carbide (SiC) or gallium nitride (GaN). The switching element 40 may include a first electrode 41, a second electrode 42, and a third electrode 43. The freewheeling diode 45 may include a fourth electrode 46 and a fifth electrode 47. Each of the first electrode 41, the second electrode 42, the third electrode 43, the fourth electrode 46, and the fifth electrode 47 may be, for example, an Al electrode, an AlSi electrode, or an AlCu electrode.

The power semiconductor element (40, 45) is bonded to the conductive circuit pattern 14 via the conductive bonding member 50. The first electrode 41 of the switching element 40 is bonded to the conductive circuit pattern 14 by using the conductive bonding member 50. The fourth electrode 46 of the freewheeling diode 45 is bonded to the conductive circuit pattern 14 by using the conductive bonding member 50. The conductive joining member 50 may be solder. The solder may be lead-free solder such as Sn—Cu based solder, Sn—Ag based solder, Sn—Ag—Cu based solder or Sn—Sb based solder. The conductive joining member 50 is not particularly limited, but may be a conductive adhesive or a conductive nanoparticle sintered body. The conductive adhesive may be a resin adhesive in which a metal filler is dispersed, for example, an epoxy resin in which a silver filler is dispersed. The conductive nanoparticles sintered body may be formed by sintering silver nanoparticles or copper nanoparticles at a temperature of 350 ° C. or lower.

The electrode terminal 20 electrically connects the conductive circuit pattern 14 and an external circuit (not shown). One end of the electrode terminal 20 faces the conductive circuit pattern 14 and is connected to the cushioning member 60. The other end of the electrode terminal 20 is electrically connected to an external circuit. The electrode terminal 20 has a first main surface 21 facing the cushioning member 60 and a second main surface 22 opposite to the first main surface 21. The electrode terminal 20 may be made of a metal having a low electrical resistivity and a high thermal conductivity, such as copper or aluminum. The electrode terminal 20 has rigidity so that it can maintain its shape by itself.

The electrode terminal 20 may have a thickness t ₄ of 0.1 mm or more. Therefore, a large current can be supplied to the power semiconductor device (40, 45) through the electrode terminal 20. The electrode terminal 20 may have a thickness t ₄ of 1.5 mm or less. Therefore, the electrode terminal 20 and the cushioning member 60 can be firmly bonded to each other by using the ultrasonic bonding method, and the cushioning member 60 and the conductive circuit pattern 14 can be firmly bonded to each other. In the present specification, the thickness t ₄ of the electrode terminal 20 is defined as the distance between the first main surface 21 and the second main surface 22 (excluding the uneven structure 23). The electrode terminal 20 may have a width of, for example, 0.1 mm or more. Therefore, a large current can be supplied to the power semiconductor device (40, 45) through the electrode terminal 20. The electrode terminal 20 may have a width of, for example, 5.0 mm or less. Therefore, the number of electrode terminals 20 included in the power semiconductor module 1 can be increased. In the present specification, the width of the electrode terminal 20 is defined as the length of the electrode terminal 20 in the lateral direction (y direction).

With reference to FIG. 2, the electrode terminal 20 has an uneven structure 23 on the second main surface 22. The concave-convex structure 23 of the electrode terminal 20 is complementary to the protrusion 71 (see FIG. 6) of the ultrasonic horn 70 used for ultrasonically bonding the electrode terminal 20 to the conductive circuit pattern 14 via the cushioning member 60. It has a shape. The concave-convex structure 23 of the electrode terminal 20 may have, for example, a period p of 0.3 mm or more and 0.5 mm or less and a depth d of 0.1 mm or more and 0.3 mm or less.

The electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60. The electrode terminal 20 is separated from the conductive circuit pattern 14. The electrode terminal 20 is not directly bonded to the conductive circuit pattern 14. The first bonding layer 61 is formed at a part of the interface between the electrode terminal 20 and the cushioning member 60. The first bonding layer 61 may be an alloy layer containing the material of the electrode terminal 20 and the material of the cushioning member 60. A part of the interface between the electrode terminal 20 and the cushioning member 60 is a part of the interface between the electrode terminal 20 and the cushioning member 60 which overlaps with the ultrasonic horn 70 in the plan view of the conductive circuit pattern 14. A second bonding layer 62 is formed at a part of the interface between the cushioning member 60 and the conductive circuit pattern 14. The second bonding layer 62 may be an alloy layer containing the material of the cushioning member 60 and the material of the conductive circuit pattern 14. A part of the interface between the cushioning member 60 and the conductive circuit pattern 14 is a part of the interface between the cushioning member 60 and the conductive circuit pattern 14 which overlaps with the ultrasonic horn 70 in the plan view of the conductive circuit pattern 14. .. The cushioning member 60, the first bonding layer 61, and the second bonding layer 62 have conductivity.

The cushioning member 60 is made of a material having a lower yield strength than the conductive circuit pattern 14 and the electrode terminal 20. As used herein, proof stress is defined as the stress at which a permanent strain of 0.2% occurs when the stress is removed in a material that does not have a well-defined yield point. Since the cushioning member 60 is made of a material having a lower yield strength than the conductive circuit pattern 14 and the electrode terminal 20, when the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60, the cushioning member 60 is used. It is more easily plastically deformed than the conductive circuit pattern 14 and the electrode terminal 20. The cushioning member 60 is made of a material having a conductive circuit pattern 14 and a melting point lower than that of the electrode terminal 20. The cushioning member 60 may have a melting point of 250 ° C. or lower. The cushioning member 60 may be a Sn—Cu based solder, a Sn—Ag based solder, a Sn—Ag—Cu based solder, or a Sn—Sb based solder. The cushioning member 60 made of Sn—Cu-based solder, Sn-Ag-based solder, Sn-Ag-Cu-based solder, or Sn—Sb-based solder has a cushioning member 60 as compared with the cushioning member of the comparative example made of Sn or In. It is possible to improve the reliability of the connection between the electrode terminal 20 and the conductive circuit pattern 14 via the solder.

The cushioning member 60 may have a thickness t ₃ of 0.1 mm or more. Therefore, the electrode terminal 20 can be firmly bonded to the conductive circuit pattern 14 via the cushioning member 60, and the power semiconductor module 1 has high reliability. The cushioning member 60 may have a thickness t ₃ of less than 0.5 mm. Therefore, when the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60, not only the interface between the cushioning member 60 and the electrode terminal 20 but also the electrode terminal 20 and the conductive circuit pattern 14 are bonded. A sufficient load and ultrasonic vibration can be applied from the ultrasonic horn 70 to the interface between them. The electrode terminals 20 may be ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60.

With reference to FIG. 3, in the plan view of the conductive circuit pattern 14, all of the outer circumference 60a of the cushioning member 60 may be outside the outer circumference 21a of the first main surface 21 of the electrode terminal 20. In the plan view of the conductive circuit pattern 14, the cushioning member 60 protrudes from both sides of the first main surface 21 in the longitudinal direction (for example, the x direction) of the electrode terminal 20 and is short of the electrode terminal 20. It may protrude from both sides of the second main surface 21 in the hand direction (for example, the y direction). Since all of the first main surface 21 of the electrode terminal 20 is bonded to the cushioning member 60, the electrode terminal 20 and the cushioning member 60 can be firmly bonded to each other. In the plan view of the conductive circuit pattern 14, the second area of the shock absorber 60 may be larger than 100% of the first area of the first main surface 21 of the electrode terminal 20. In the plan view of the conductive circuit pattern 14, the second area of the shock absorber 60 may be 110% or less of the first area of the first main surface 21 of the electrode terminal 20.

With reference to FIG. 1, the second electrode 42 of the switching element 40 and the conductive circuit pattern 14 are electrically connected to each other by using the conductive wire 55. The third electrode 43 of the switching element 40 and the fifth electrode 47 of the freewheeling diode 45 are electrically connected to each other by using the conductive wire 56. The fifth electrode 47 of the freewheeling diode 45 and the conductive circuit pattern 14 are electrically connected to each other by using the conductive wire 57.

With reference to FIG. 1, the case 65 has electrical insulation. Specifically, the case 65 may be made of a resin having an electrically insulating property. Case 65 may be composed of, for example, polyphenylene sulfide (PPS). The case 65 may be adhered to the insulating substrate 11. The case 65 may be adhered to the insulating resin sheet 13 of the insulating substrate 11 by using the adhesive 18. The adhesive 18 may be a resin adhesive such as, for example, a silicone resin adhesive. The electrode terminal 20 may be integrated with the case 65.

With reference to FIG. 1, the sealing member 67 seals a power semiconductor element (40, 45), a conductive circuit pattern 14, a cushioning member 60, and a part of an electrode terminal 20 facing the cushioning member 60. do. The sealing member 67 has an electrical insulating property. The sealing member 67 may be made of, for example, an epoxy resin. The sealing member 67 may be provided inside the case 65. The power semiconductor module 1 does not include the case 65, and the sealing member 67 may be a transfer mold sealing resin.

A first example of the method for manufacturing the power semiconductor module 1 of the present embodiment will be described with reference to FIGS. 4 to 7.

The method for manufacturing the power semiconductor module 1 of the present embodiment includes joining the power semiconductor element (40, 45) to the conductive circuit pattern 14 (S10) via the conductive joining member 50. The insulating substrate 11 includes an insulating resin sheet 13 and a conductive circuit pattern 14 provided on the first surface 13a of the insulating resin sheet 13. For example, when the conductive joining member 50 is solder, the power semiconductor element (40, 45) may be soldered to the conductive circuit pattern 14 by reflowing the solder.

With reference to FIG. 4, the method of manufacturing the power semiconductor module 1 of the present embodiment further comprises joining the electrode terminal 20 to the conductive circuit pattern 14 via the cushioning member 60 (S20). The electrode terminal 20 has a first main surface 21 facing the cushioning member 60 and a second main surface 22 opposite to the first main surface 21. The cushioning member 60 is made of a material having a lower yield strength and a lower melting point than the conductive circuit pattern 14 and the electrode terminal 20. The cushioning member 60 may have a melting point of 250 ° C. or lower.

With reference to FIG. 5, joining the electrode terminal 20 to the conductive circuit pattern 14 via the cushioning member 60 (S20) involves stacking the cushioning member 60 on the conductive circuit pattern 14 and the electrodes on the cushioning member 60. Includes stacking terminals 20. The cushioning member 60 is in contact with the conductive circuit pattern 14 and the electrode terminal 20. The cushioning member 60 stacked on the conductive circuit pattern 14 may have a thickness t ₆ of 0.2 mm or more. Therefore, when the electrode terminal 20 is joined to the conductive circuit pattern 14 by using the ultrasonic horn 70, the cushioning member 60 is excluded from between the electrode terminal 20 and the conductive circuit pattern 14, and the electrode terminal 20 is the conductive circuit pattern. It is prevented from being directly joined to 14. While the electrode terminal 20 is joined to the conductive circuit pattern 14 using the ultrasonic horn 70, the cushioning member 60 continues to exist between the electrode terminal 20 and the conductive circuit pattern 14. The cushioning member 60 stacked on the conductive circuit pattern 14 may have a thickness t ₆ of 0.5 mm or less. Therefore, the pressure applied by the ultrasonic horn 70 and the ultrasonic vibration can be transmitted not only to the interface between the electrode terminal 20 and the cushioning member 60 but also to the interface between the cushioning member 60 and the conductive circuit pattern 14. .. Using the ultrasonic horn 70, the electrode terminal 20 and the cushioning member 60 are ultrasonically bonded to each other, and the cushioning member 60 and the conductive circuit pattern 14 are ultrasonically bonded to each other.

Referring to FIGS. 6 and 7, bonding the electrode terminal 20 to the conductive circuit pattern 14 via the shock absorber 60 (S20) pushes the ultrasonic horn 70 onto the second main surface 22 of the electrode terminal 20. It includes ultrasonically bonding the electrode terminal 20 and the cushioning member 60 by contact. By pressing the ultrasonic horn 70 against the second main surface 22, the buffer member 60 undergoes a phase transition from the solid phase to the liquid phase. The first bonding layer 61 is formed on a part of the interface between the electrode terminal 20 and the cushioning member 60. The electrode terminal 20 and the cushioning member 60 are ultrasonically bonded to each other in an environment of room temperature.

With reference to FIGS. 6 and 7, joining the electrode terminal 20 to the conductive circuit pattern 14 via the cushioning member 60 (S20) includes joining the cushioning member 60 and the conductive circuit pattern 14. A second bonding layer 62 is formed at a part of the interface between the cushioning member 60 and the conductive circuit pattern 14. Specifically, the cushioning member 60 and the conductive circuit pattern 14 may be ultrasonically bonded by pressing the ultrasonic horn 70 against the second main surface 22. That is, by pressing the ultrasonic horn 70 against the second main surface 22 of the electrode terminal 20, the electrode terminal 20 and the cushioning member 60 are not only ultrasonically bonded to each other, but also the cushioning member 60 and the conductive circuit pattern 14. May be ultrasonically bonded to each other. By pressing the ultrasonic horn 70 against the second main surface 22 of the electrode terminal 20, not only the first bonding layer 61 but also the second bonding layer 62 may be formed. While the electrode terminal 20 is joined to the conductive circuit pattern 14 using the ultrasonic horn 70, the electrode terminal 20 is separated from the conductive circuit pattern 14.

Specifically, the ultrasonic horn 70 comes into contact with the second main surface 22 of the electrode terminal 20. The ultrasonic horn 70 presses the electrode terminal 20 toward the insulating substrate 11. The ultrasonic horn 70 applies ultrasonic waves vibrating in the second main surface 22 (xy surface) of the electrode terminal 20 to the electrode terminal 20, the cushioning member 60, and the conductive circuit pattern 14. The frequency of the ultrasonic wave applied from the ultrasonic horn 70 to the electrode terminal 20, the buffer member 60, and the conductive circuit pattern 14 may be, for example, several tens of kHz.

The ultrasonic vibration applied from the ultrasonic horn 70 causes the first main surface 21 of the electrode terminal 20 and the cushioning member 60 to slide against each other. The film covering the first main surface 21 of the electrode terminal 20 (for example, an oxide film) and the film covering the surface of the buffer member 60 (for example, an oxide film) are removed, and the first main surface of the electrode terminal 20 is removed. The new surface of the surface 21 and the new surface of the cushioning member 60 are exposed. The new surface of the first main surface 21 of the electrode terminal 20 and the new surface of the cushioning member 60 are in contact with each other, and the first bonding layer 61 is formed at the interface between the first main surface 21 of the electrode terminal 20 and the cushioning member 60. It is formed. In this way, the electrode terminal 20 and the cushioning member 60 are ultrasonically bonded to each other.

Due to the ultrasonic vibration applied from the ultrasonic horn 70, the cushioning member 60 and the surface of the conductive circuit pattern 14 rub against each other, and the coating film (for example, an oxide film) covering the surface of the cushioning member 60 and the conductive circuit pattern 14 The film (for example, an oxide film) covering the surface of the buffer member 60 is removed, and the new surface of the cushioning member 60 and the new surface of the conductive circuit pattern 14 are exposed. The new surface of the cushioning member 60 and the new surface of the conductive circuit pattern 14 come into contact with each other, and a second bonding layer 62 is formed at the interface between the cushioning member 60 and the new surface of the conductive circuit pattern 14. In this way, the cushioning member 60 and the new surface of the conductive circuit pattern 14 are ultrasonically bonded to each other.

When the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60, the electrode terminal 20 and the cushioning member 60 rub against each other, so that the first main surface 21 of the electrode terminal 20 and the cushioning member 60 Friction heat is generated at the interface with. When the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60, the cushioning member 60 and the conductive circuit pattern 14 rub against each other, so that the interface between the cushioning member 60 and the conductive circuit pattern 14 is formed. Friction heat is generated. Due to these frictional heats, the temperature of the first main surface 21 of the electrode terminal 20, the temperature of the cushioning member 60, and the temperature of the conductive circuit pattern 14 facing the cushioning member 60 rise. The temperature of the first main surface 21 of the electrode terminal 20, the temperature of the cushioning member 60, and the temperature of the conductive circuit pattern 14 facing the cushioning member 60 may be increased to, for example, 250 ° C. or higher.

The cushioning member 60 has a melting point lower than that of the conductive circuit pattern 14 and the electrode terminal 20. The melting point of the cushioning member 60 is the temperature of the first main surface 21 of the electrode terminal 20 while the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60, the temperature of the cushioning member 60, and the cushioning member 60. It is lower than the temperature of the conductive circuit pattern 14 facing the surface. For example, the melting point of the cushioning member 60 is 250 ° C. or lower, and the temperature of the first main surface 21 of the electrode terminal 20 while the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60. , The temperature of the cushioning member 60 and the temperature of the conductive circuit pattern 14 facing the cushioning member 60 may be higher than 250 ° C. By pressing the ultrasonic horn 70 against the second main surface 22 of the electrode terminal 20, the buffer member 60 undergoes a phase transition from the solid phase to the liquid phase. While the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the buffer member 60, the electrode terminal 20 and the conductive circuit pattern 14 remain solid phase. When the buffer member 60 undergoes a phase transition from a solid phase to a liquid phase, the buffer member 60 is generated between the frictional heat generated between the electrode terminal 20 and the buffer member 60 and between the buffer member 60 and the conductive circuit pattern 14. Absorbs part of the frictional heat. In this way, the cushioning member 60 can prevent the insulating resin sheet 13 contained in the insulating substrate 11 from being thermally damaged.

Further, while the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60, the cushioning member 60 is always interposed between the electrode terminal 20 and the conductive circuit pattern 14, and the electrode terminal 20 is separated from the conductive circuit pattern 14. The cushioning member 60 has a lower yield strength and a lower melting point than the conductive circuit pattern 14 and the electrode terminal 20. When the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60, the cushioning member 60 is selectively deformed and also serves as a cushion against the stress applied by the ultrasonic horn 70. Fulfill. The cushioning member 60 can prevent the insulating resin sheet 13 contained in the insulating substrate 11 from being mechanically damaged.

The protrusion 71 of the ultrasonic horn 70 bites into the second main surface 22 of the electrode terminal 20. Due to the pressure applied to the cushioning member 60 by the ultrasonic horn 70 and the ultrasonic vibration, the cushioning member 60 is stretched in the vibration direction (direction in the xy plane) of the ultrasonic vibration, and the thickness of the cushioning member 60 is increased. Decrease.

With reference to FIG. 4, in the method of manufacturing the power semiconductor module 1 of the present embodiment, the power semiconductor element (40, 45) and the conductive circuit pattern 14 are electrically connected to each other by using the conductive wires 55-57. Further equipped to do (S30). Specifically, the second electrode 42 of the switching element 40 and the conductive circuit pattern 14 are electrically connected to each other by using the conductive wire 55. Using the conductive wire 56, the third electrode 43 of the switching element 40 and the fifth electrode 47 of the freewheeling diode 45 are electrically connected to each other. Using the conductive wire 57, the fifth electrode 47 of the freewheeling diode 45 and the conductive circuit pattern 14 are electrically connected to each other.

With reference to FIG. 4, the method of manufacturing the power semiconductor module 1 of the present embodiment may further include adhering the case 65 to the insulating substrate 11 (S40). The case 65 may be adhered to the insulating resin sheet 13 of the insulating substrate 11 by using the adhesive 18. The electrode terminal 20 may be integrated with the case 65.

With reference to FIG. 4, the method of manufacturing the power semiconductor module 1 of the present embodiment includes a power semiconductor element (40, 45), a conductive circuit pattern 14, a cushioning member 60, and an electrode terminal facing the cushioning member 60. It further comprises sealing a part of 20 with a sealing member 67 (S50). The sealing member 67 may be formed, for example, by injecting the sealing resin into the inside of the case 65 and then curing the sealing resin. The power semiconductor module 1 does not include a case 65, and the power semiconductor element (40, 45), the conductive circuit pattern 14, the cushioning member 60, and a part of the electrode terminal 20 facing the cushioning member 60 are transferred. It may be sealed with the sealing member 67 by the molding method. In the sealing member 67, for example, a power semiconductor element (40, 45), a conductive circuit pattern 14, a cushioning member 60, and an electrode terminal 20 are arranged in a mold, and a sealing resin is injected into the mold. It may then be formed by curing the encapsulating resin.

In the second example of the method for manufacturing the power semiconductor module 1 of the present embodiment, after the case 65 is bonded to the insulating substrate 11 (S40), the electrode terminals 20 are bonded to the conductive circuit pattern 14 via the cushioning member 60. (S20) and electrically connecting the power semiconductor element (40, 45) and the conductive circuit pattern 14 to each other (S30) may be performed by using the conductive wires 55-57.

A power semiconductor module of a comparative example will be described with reference to FIG. The power semiconductor module of the comparative example has the same configuration as the power semiconductor module 1 of the present embodiment, but differs in the following points. In the power semiconductor module of the comparative example, the electrode terminal 20 is ultrasonically bonded directly to the conductive circuit pattern 14 without the intervention of the shock absorber 60. The manufacturing method of the power semiconductor module of the comparative example includes directly joining the electrode terminal 20 to the conductive circuit pattern 14 by an ultrasonic joining method. While the electrode terminal 20 is bonded to the conductive circuit pattern 14 by the ultrasonic bonding method, the cushioning member 60 is not interposed between the electrode terminal 20 and the conductive circuit pattern 14.

In the method of manufacturing the power semiconductor module of the comparative example, when the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 using the ultrasonic horn 70, the electrode terminal 20 and the conductive circuit pattern 14 rub against each other, so that the electrodes Friction heat is generated at the interface between the terminal 20 and the conductive circuit pattern 14. The temperature of the insulating resin sheet 13 becomes higher than the softening temperature of the insulating resin sheet 13, and the insulating resin sheet 13 is thermally decomposed. For example, the surface of the insulating resin sheet 13 is oxidized or carbonized. In the method of manufacturing the power semiconductor module of the comparative example, the insulating resin sheet 13 is thermally damaged and the insulating resin sheet 13 is deteriorated. The dielectric breakdown withstand voltage of the insulating resin sheet 13 is reduced, and therefore the power semiconductor module of the comparative example has low reliability.

Further, in the method of manufacturing the power semiconductor module of the comparative example, the insulating resin sheet 13 is softened and deformed by the frictional heat generated at the interface between the electrode terminal 20 and the conductive circuit pattern 14. In addition, in the method of manufacturing the power semiconductor module of the comparative example, the pressure applied by the ultrasonic horn 70 when the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 by using the ultrasonic horn 70 is the cushioning member 60. It is applied to the insulating resin sheet 13 without being relaxed by. In the power semiconductor module of the comparative example, the insulating resin sheet 13 is mechanically damaged such as a crack 13g. In FIG. 8, the crack 13 g mainly extends along the direction (xy in-plane direction) perpendicular to the thickness direction (z direction) of the insulating resin sheet 13, but the crack 13 g is the insulating resin sheet. It may extend along the thickness direction (z direction) of 13. In the method of manufacturing the power semiconductor module of the comparative example, the insulating resin sheet 13 is mechanically damaged and the insulating resin sheet 13 is deteriorated. The dielectric breakdown withstand voltage of the insulating resin sheet 13 is reduced, and therefore the power semiconductor module of the comparative example has low reliability.

The effects of the power semiconductor module 1 of the present embodiment and the manufacturing method thereof will be described.
The power semiconductor module 1 of the present embodiment includes an insulating substrate 11, a power semiconductor element (40, 45), and an electrode terminal 20. The insulating substrate 11 includes an insulating resin sheet 13 and a conductive circuit pattern 14 provided on the first surface 13a of the insulating resin sheet 13. The power semiconductor element (40, 45) is bonded to the conductive circuit pattern 14 via the conductive bonding member 50. The electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60. The electrode terminal 20 has a first main surface 21 facing the cushioning member 60 and a second main surface 22 opposite to the first main surface 21. The cushioning member 60 is made of a material having a lower yield strength and a lower melting point than the conductive circuit pattern 14 and the electrode terminal 20. The electrode terminal 20 is separated from the conductive circuit pattern 14.

In the power semiconductor module 1 of the present embodiment, the insulating substrate 11 includes an insulating resin sheet 13. Therefore, the cost of the power semiconductor module 1 of the present embodiment is reduced.

The cushioning member 60 has a melting point lower than that of the conductive circuit pattern 14 and the electrode terminal 20. By pressing the ultrasonic horn 70 against the second main surface 22 of the electrode terminal 20, the buffer member 60 undergoes a phase transition from the solid phase to the liquid phase. When the buffer member 60 undergoes a phase transition from a solid phase to a liquid phase, the buffer member 60 is generated at the interface between the electrode terminal 20 and the buffer member 60 and the interface between the buffer member 60 and the conductive circuit pattern 14. Absorbs part of the frictional heat. The cushioning member 60 can prevent the insulating resin sheet 13 contained in the insulating substrate 11 from being thermally damaged.

Further, while the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60, the cushioning member 60 is always interposed between the electrode terminal 20 and the conductive circuit pattern 14, and the electrode terminal 20 is separated from the conductive circuit pattern 14. The cushioning member 60 has a lower yield strength and a lower melting point than the conductive circuit pattern 14 and the electrode terminal 20. When the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60, the cushioning member 60 is selectively deformed and also serves as a cushion against the stress applied by the ultrasonic horn 70. Fulfill. The cushioning member 60 can prevent the insulating resin sheet 13 contained in the insulating substrate 11 from being mechanically damaged. The power semiconductor module 1 of this embodiment has high reliability.

In the power semiconductor module 1 of the present embodiment, the cushioning member 60 is selectively deformed when the electrode terminal 20 is joined to the conductive circuit pattern 14 via the cushioning member 60 by using the ultrasonic horn 70. It is configured in. Therefore, the amount of deformation of the electrode terminal 20 when the protrusion 71 of the ultrasonic horn 70 bites into the second main surface 22 of the electrode terminal 20 is reduced. Therefore, when the electrode terminal 20 is deformed, the amount of debris of the electrode terminal 20 scattered from between the electrode terminal 20 and the ultrasonic horn 70 is also reduced. The power semiconductor module 1 of this embodiment has high reliability.

The power semiconductor module 1 of the present embodiment is configured so that it can be manufactured in an environment of room temperature. In the power semiconductor module 1 of the present embodiment, the electrode terminals 20 are joined to the conductive circuit pattern 14 via the shock absorber 60 without a heating device. The power semiconductor module 1 of the present embodiment is configured so as to reduce the manufacturing cost of the power semiconductor module 1 and the space for manufacturing the power semiconductor module 1.

The method for manufacturing the power semiconductor module 1 of the present embodiment includes joining the power semiconductor element (40, 45) to the conductive circuit pattern 14 (S10) via the conductive joining member 50. The insulating substrate 11 includes an insulating resin sheet 13 and a conductive circuit pattern 14 provided on the first surface 13a of the insulating resin sheet 13. The method for manufacturing the power semiconductor module 1 of the present embodiment further comprises joining the electrode terminal 20 to the conductive circuit pattern 14 via the cushioning member 60 (S20). The electrode terminal 20 has a first main surface 21 facing the cushioning member 60 and a second main surface 22 opposite to the first main surface 21. The cushioning member 60 is made of a material having a lower yield strength and a lower melting point than the conductive circuit pattern 14 and the electrode terminal 20. To join the electrode terminal 20 to the conductive circuit pattern 14 via the cushioning member 60 (S20), the cushioning member 60 is stacked on the conductive circuit pattern 14, the electrode terminal 20 is stacked on the cushioning member 60, and the electrode terminal 20 is stacked. This includes pressing the ultrasonic horn 70 against the second main surface 22 to ultrasonically join the electrode terminal 20 and the cushioning member 60, and joining the cushioning member 60 and the conductive circuit pattern 14. By pressing the ultrasonic horn 70 against the second main surface 22, the buffer member 60 undergoes a phase transition from the solid phase to the liquid phase. The electrode terminal 20 is separated from the conductive circuit pattern 14.

In the method for manufacturing the power semiconductor module 1 of the present embodiment, the insulating substrate 11 includes an insulating resin sheet 13. Therefore, the cost of the power semiconductor module 1 of the present embodiment is reduced.

The cushioning member 60 has a melting point lower than that of the conductive circuit pattern 14 and the electrode terminal 20. By pressing the ultrasonic horn 70 against the second main surface 22 of the electrode terminal 20, the buffer member 60 undergoes a phase transition from the solid phase to the liquid phase. When the buffer member 60 undergoes a phase transition from a solid phase to a liquid phase, the buffer member 60 is generated at the interface between the electrode terminal 20 and the buffer member 60 and the interface between the buffer member 60 and the conductive circuit pattern 14. Absorbs part of the frictional heat. The cushioning member 60 can prevent the insulating resin sheet 13 contained in the insulating substrate 11 from being thermally damaged.

Further, while the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60, the cushioning member 60 is always interposed between the electrode terminal 20 and the conductive circuit pattern 14, and the electrode terminal 20 is separated from the conductive circuit pattern 14. The cushioning member 60 has a lower yield strength and a lower melting point than the conductive circuit pattern 14 and the electrode terminal 20. When the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60, the cushioning member 60 is selectively deformed and also serves as a cushion against the stress applied by the ultrasonic horn 70. Fulfill. The cushioning member 60 can prevent the insulating resin sheet 13 contained in the insulating substrate 11 from being mechanically damaged. According to the method for manufacturing the power semiconductor module 1 of the present embodiment, the power semiconductor module 1 having high reliability can be obtained.

In the method for manufacturing the power semiconductor module 1 of the present embodiment, the cushioning member 60 is selected when the electrode terminal 20 is joined to the conductive circuit pattern 14 via the cushioning member 60 by using the ultrasonic horn 70 (S20). Is transformed. Therefore, the amount of deformation of the electrode terminal 20 when the protrusion 71 of the ultrasonic horn 70 bites into the second main surface 22 of the electrode terminal 20 is reduced. Therefore, when the electrode terminal 20 is deformed, the amount of debris of the electrode terminal 20 scattered from between the electrode terminal 20 and the ultrasonic horn 70 is also reduced. According to the method for manufacturing the power semiconductor module 1 of the present embodiment, the power semiconductor module 1 having high reliability can be obtained.

The method for manufacturing the power semiconductor module 1 of the present embodiment can be performed in an environment of room temperature. In the method for manufacturing the power semiconductor module 1 of the present embodiment, a heating device is not required when the electrode terminal 20 is bonded to the conductive circuit pattern 14 via the cushioning member 60 (S20). The method for manufacturing the power semiconductor module 1 of the present embodiment can reduce the manufacturing cost of the power semiconductor module 1 and the space for manufacturing the power semiconductor module 1.

In the power semiconductor module 1 and the method for manufacturing the power semiconductor module 1 of the present embodiment, the shock absorber 60 may have a melting point of 250 ° C. or lower. By pressing the ultrasonic horn 70 against the second main surface 22 of the electrode terminal 20, the buffer member 60 undergoes a phase transition from the solid phase to the liquid phase. The cushioning member 60 absorbs a part of frictional heat generated at the interface between the electrode terminal 20 and the cushioning member 60 and the interface between the cushioning member 60 and the conductive circuit pattern 14. The cushioning member 60 can prevent the insulating resin sheet 13 contained in the insulating substrate 11 from being thermally damaged. The power semiconductor module 1 of this embodiment has high reliability.

In the power semiconductor module 1 and the manufacturing method thereof of the present embodiment, the shock absorber 60 may be Sn—Cu based solder, Sn—Ag based solder, Sn—Ag—Cu based solder or Sn—Sb based solder. .. Since the cushioning member 60 is a Sn—Cu-based solder, a Sn-Ag-based solder, a Sn-Ag-Cu-based solder, or a Sn—Sb-based solder, the electrode terminal 20 and the conductive circuit pattern 14 via the cushioning member 60 The reliability of the soldering between can be improved. The power semiconductor module 1 of this embodiment has high reliability.

In the power semiconductor module 1 and the manufacturing method thereof of the present embodiment, in the conductive circuit pattern 14, all of the outer peripheral 60a of the cushioning member 60 may be outside the outer peripheral 21a of the first main surface 21 of the electrode terminal 20. good. The electrode terminal 20 can be easily aligned with the cushioning member 60.

In the power semiconductor module 1 of the present embodiment, in the plan view of the conductive circuit pattern 14, the second area of the shock absorber 60 is larger than 100% of the first area of the first main surface 21 of the electrode terminal 20. And it may be 110% or less. Therefore, the electrode terminal 20 can be easily aligned with the cushioning member 60, and the electrode terminal 20 can be arranged in the power semiconductor module 1 at a high density.

The power semiconductor module 1 of the present embodiment may further include a sealing member 67. The sealing member 67 seals the power semiconductor element (40, 45), the conductive circuit pattern 14, the cushioning member 60, and a part of the electrode terminal 20 facing the cushioning member 60. The sealing member 67 may reinforce the bond between the electrode terminal 20 and the conductive circuit pattern 14 via the cushioning member 60. The power semiconductor module 1 of this embodiment has high reliability.

In the method for manufacturing the power semiconductor module 1 of the present embodiment, the cushioning member 60 stacked on the conductive circuit pattern 14 may have a thickness t ₆ of 0.2 mm or more. Therefore, when the electrode terminal 20 is joined to the conductive circuit pattern 14 by using the ultrasonic horn 70, the cushioning member 60 is excluded from between the electrode terminal 20 and the conductive circuit pattern 14, and the electrode terminal 20 is the conductive circuit pattern. It is prevented from being directly joined to 14. The power semiconductor module 1 of this embodiment has high reliability.

Embodiment 2.
The power semiconductor module 1b and the manufacturing method thereof according to the second embodiment will be described with reference to FIG. The power semiconductor module 1b of the present embodiment has the same configuration as the power semiconductor module 1 of the first embodiment, but is mainly different in the following points.

In the power semiconductor module 1b of the present embodiment, the cushioning member 60 has the same or lower melting point as the conductive joining member 50. The cushioning member 60 may be made of the same material as the conductive joining member 50. The second bonding layer 62 may be formed over the entire interface between the cushioning member 60 and the conductive circuit pattern 14.

With reference to FIGS. 10 to 12, the method for manufacturing the power semiconductor module 1b of the present embodiment includes the same steps as the method for manufacturing the power semiconductor module 1 of the first embodiment, but mainly in the following points. different.

With reference to FIG. 10, joining the power semiconductor element (40, 45) to the conductive circuit pattern 14 via the conductive joining member 50 (S10) causes the conductive joining member 50 to be stacked on the conductive circuit pattern 14. In addition, the power semiconductor elements (40, 45) are stacked on the conductive bonding member 50, and heat is applied to the power semiconductor elements (40, 45) via the conductive bonding member 50 in the conductive circuit pattern 14. Including joining to. To join the electrode terminal 20 to the conductive circuit pattern 14 via the cushioning member 60 (S20), the cushioning member 60 is stacked on the conductive circuit pattern 14 and the heat is applied to the cushioning member 60 and the conductive circuit pattern 14. This includes joining the cushioning member 60 to the conductive circuit pattern 14. That is, by applying heat, the power semiconductor element (40, 45) is bonded to the conductive circuit pattern 14 via the conductive bonding member 50, and the cushioning member 60 is also bonded to the conductive circuit pattern 14. By applying heat, a second bonding layer 62 is formed at the interface between the cushioning member 60 and the conductive circuit pattern 14.

Specifically, the conductive bonding member 50 is stacked on the conductive circuit pattern 14, and then the power semiconductor elements (40, 45) are stacked on the conductive bonding member 50. The cushioning member 60 is stacked on the conductive circuit pattern 14. Then, the insulating substrate 11, the conductive joining member 50, the cushioning member 60, and the power semiconductor element (40, 45) are put into the heating furnace. The conductive joining member 50 and the cushioning member 60 are heated in the heating furnace. In this way, the power semiconductor element (40, 45) is bonded to the conductive circuit pattern 14 via the conductive bonding member 50, and the second bonding layer 62 is provided at the interface between the cushioning member 60 and the conductive circuit pattern 14. It is formed.

With reference to FIGS. 11 and 12, bonding the electrode terminal 20 to the conductive circuit pattern 14 via the cushioning member 60 (S20) involves stacking the electrode terminal 20 on the cushioning member 60 and forming the electrode terminal 20. It includes pressing the ultrasonic horn 70 against the second main surface 22 to ultrasonically bond the electrode terminal 20 and the cushioning member 60. By pressing the ultrasonic horn 70 against the second main surface 22, the buffer member 60 undergoes a phase transition from the solid phase to the liquid phase. The first bonding layer 61 is formed on a part of the interface between the electrode terminal 20 and the cushioning member 60. The electrode terminal 20 and the cushioning member 60 are ultrasonically bonded to each other in an environment of room temperature.

The effects of the power semiconductor module 1b of the present embodiment and the manufacturing method thereof will be described.
In the power semiconductor module 1b of the present embodiment, the cushioning member 60 has the same or lower melting point as the conductive joining member 50. The power semiconductor module 1b is configured so that when the power semiconductor element (40, 45) is bonded to the conductive circuit pattern 14 via the conductive bonding member 50, the shock absorber 60 can also be bonded to the conductive circuit pattern 14. ing. The power semiconductor module 1b of the present embodiment is configured so that the number of steps for manufacturing the power semiconductor module 1b can be reduced.

In the method for manufacturing the power semiconductor module 1b of the present embodiment, joining the power semiconductor element (40, 45) to the conductive circuit pattern 14 via the conductive joining member 50 (S10) is performed on the conductive circuit pattern 14. Stacking the conductive joining member 50, stacking the power semiconductor element (40, 45) on the conductive joining member 50, and applying heat to the power semiconductor element (40) via the conductive joining member 50. , 45) includes joining to the conductive circuit pattern 14. By applying heat, the cushioning member 60 and the conductive circuit pattern 14 are joined. As described above, when the power semiconductor element (40, 45) is bonded to the conductive circuit pattern 14 via the conductive bonding member 50 (S10), the shock absorber 60 can also be bonded to the conductive circuit pattern 14. According to the method for manufacturing the power semiconductor module 1b of the present embodiment, the number of steps for manufacturing the power semiconductor module 1b can be reduced.

Embodiment 3.
The power semiconductor module 1c according to the third embodiment will be described with reference to FIGS. 13 to 16. The power semiconductor module 1c of the present embodiment has the same configuration as the power semiconductor module 1 of the first embodiment, but is mainly different in the following points.

In the power semiconductor module 1c of the present embodiment, the electrode terminal 20 includes one or more protrusions 25 protruding from the first main surface 21. The one or more protrusions 25 are separated from the conductive circuit pattern 14. The contact area between the electrode terminal 20 and the cushioning member 60 in the power semiconductor module 1c of the present embodiment is larger than the contact area between the electrode terminal 20 and the cushioning member 60 in the power semiconductor module 1 of the first embodiment. To increase. The one or more protrusions 25 can increase the bonding strength between the electrode terminal 20 and the conductive circuit pattern 14 via the cushioning member 60.

As shown in FIGS. 13 and 14, each of the one or more protrusions 25 may have a convex curved surface at its apex. Each of the one or more protrusions 25 may have, for example, the shape of a hemisphere or the shape of a semi-elliptical sphere. As shown in FIG. 15, each of the one or more protrusions 25 may have the shape of a polygonal pyramid or a cone. As shown in FIG. 16, each of the one or more protrusions 25 may have the shape of a polygonal prism or a cylinder. The one or more protrusions 25 may have the shape of a polygonal prism, a polygonal pyramid, a cone or a cylinder, and may have a convex curved surface at the top thereof.

Each of the one or more protrusions 25 may have a height h of 20% or more of the thickness t ₃ of the cushioning member 60, or a height of 30% or more of the thickness t ₃ of the cushioning member 60. may have h. Each of the one or more protrusions 25 may have a height h of 70% or less of the thickness t ₃ of the cushioning member 60, or a height of 50% or less of the thickness t ₃ of the cushioning member 60. may have h. In the present specification, the height h of each of the one or more protrusions 25 is defined as the maximum height of each top of the one or more protrusions 25 from the first main surface 21 of the electrode terminal 20. .. The thickness t ₃ of the cushioning member 60 is a portion (one or more) facing the first main surface 21 of the cushioning member 60 after the electrode terminal 20 is joined to the conductive circuit pattern 14 via the cushioning member 60. It is defined as the minimum thickness (excluding the protrusion 25).

A method for manufacturing the power semiconductor module 1c according to the third embodiment will be described with reference to FIGS. 17 to 19. The manufacturing method of the power semiconductor module 1c of the present embodiment includes the same steps as the manufacturing method of the power semiconductor module 1 of the first embodiment, but is mainly different in the following points.

Referring to FIG. 17, joining the electrode terminal 20 to the conductive circuit pattern 14 via the cushioning member 60 (S20) involves stacking the cushioning member 60 on the conductive circuit pattern 14 and the electrodes on the cushioning member 60. Includes stacking terminals 20. With reference to FIGS. 18 and 19, bonding the electrode terminal 20 to the conductive circuit pattern 14 via the cushioning member 60 (S20) causes the ultrasonic horn 70 to be pressed against the second main surface 22 to be the electrode terminal. 20 includes ultrasonic bonding of the cushioning member 60. The electrode terminal 20 includes one or more protrusions 25 protruding from the first main surface 21. The one or more protrusions 25 are separated from the conductive circuit pattern 14.

The effects of the power semiconductor module 1c of the present embodiment and the manufacturing method thereof will be described.
In the power semiconductor module 1c and the method for manufacturing the power semiconductor module 1c of the present embodiment, the electrode terminal 20 includes one or more protrusions 25 protruding from the first main surface 21. The one or more protrusions 25 are separated from the conductive circuit pattern 14.

Therefore, when the ultrasonic horn 70 is pressed against the second main surface 22 and the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the buffer member 60, the electrode terminal 20 and the buffer in this embodiment are buffered. The contact area with the member 60 is smaller than in the first embodiment. The pressure applied from the ultrasonic horn 70 to the cushioning member 60 via the electrode terminal 20 increases. The one or more protrusions 25 are formed by deformation of the cushioning member 60 and a bonding layer between the electrode terminal 20 and the conductive circuit pattern 14 via the cushioning member 60 (first bonding layer 61, second bonding layer 62). ) And promote it. In the power semiconductor module 1c of the present embodiment, the energy of ultrasonic vibration that must be supplied from the ultrasonic horn 70 can be reduced, and the electrode terminal 20 is ultrasonically bonded to the conductive circuit pattern 14 via the cushioning member 60. It is configured so that the time required to do so can be reduced. According to the method of manufacturing the power semiconductor module 1c of the present embodiment, the energy of ultrasonic vibration that must be supplied from the ultrasonic horn 70 can be reduced, and the electrode terminal 20 is connected to the electrode terminal 20 via the buffer member 60 in a conductive circuit pattern. The time required for ultrasonic bonding to 14 can be shortened.

In the power semiconductor module 1c of the present embodiment and the manufacturing method thereof, each of the one or more protrusions 25 may have a convex curved surface at the top thereof. In the one or more protrusions 25 having a convex curved surface on the top, the frictional heat generated at the interface between the electrode terminal 20 and the cushioning member 60 is locally higher than that in the one or more protrusions 25 having a corner on the top. It can suppress the excessive increase. Therefore, it is possible to prevent the insulating resin sheet 13 from being thermally damaged. The power semiconductor module 1c of the present embodiment has high reliability. According to the method for manufacturing the power semiconductor module 1c of the present embodiment, the power semiconductor module 1c having high reliability can be obtained.

Embodiment 4.
In this embodiment, the power semiconductor module according to any one of the first to third embodiments is applied to a power conversion device. Although the present invention is not limited to a specific power conversion device, the case where the present invention is applied to a three-phase inverter will be described below as the fourth embodiment.

The power conversion system shown in FIG. 20 includes a power supply 100, a power conversion device 200, and a load 300. The power supply 100 is a DC power supply, and supplies DC power to the power conversion device 200. The power supply 100 is not particularly limited, but may be composed of, for example, a DC system, a solar cell, or a storage battery, or may be composed of a rectifier circuit or an AC / DC converter connected to an AC system. The power supply 100 may be configured by a DC / DC converter that converts DC power output from the DC system into predetermined power.

The power conversion device 200 is a three-phase inverter connected between the power supply 100 and the load 300, converts the DC power supplied from the power supply 100 into AC power, and supplies AC power to the load 300. As shown in FIG. 20, the power conversion device 200 has a main conversion circuit 201 that converts DC power into AC power and outputs it, and a control circuit that outputs a control signal for controlling the main conversion circuit 201 to the main conversion circuit 201. It is equipped with 203.

The load 300 is a three-phase electric motor driven by AC power supplied from the power converter 200. The load 300 is not limited to a specific application, and is an electric motor mounted on various electric devices, and is used as an electric motor for, for example, a hybrid vehicle, an electric vehicle, a railroad vehicle, an elevator, or an air conditioner.

Hereinafter, the details of the power conversion device 200 will be described. The main conversion circuit 201 includes a switching element (not shown) and a freewheeling diode (not shown). By switching the voltage supplied from the power supply 100 by the switching element, the main conversion circuit 201 converts the DC power supplied from the power supply 100 into AC power and supplies it to the load 300. Although there are various specific circuit configurations of the main conversion circuit 201, the main conversion circuit 201 according to the present embodiment is a two-level three-phase full bridge circuit, and has six switching elements and each switching element. It may consist of six anti-parallel freewheeling diodes. As each switching element and each freewheeling diode of the main conversion circuit 201, the switching element 40 and the freewheeling diode 45 included in the power semiconductor modules 1, 1b, 1c according to any one of the above-described first to third embodiments are applied. obtain. As the power semiconductor module 202 constituting the main conversion circuit 201, the power semiconductor modules 1, 1b, 1c according to any one of the above-described first to third embodiments can be applied. The six switching elements are connected in series for each of the two switching elements to form an upper and lower arm, and each upper and lower arm constitutes each phase (U phase, V phase and W phase) of the full bridge circuit. Then, the output terminals of each upper and lower arm, that is, the three output terminals of the main conversion circuit 201 are connected to the load 300.

Further, the main conversion circuit 201 includes a drive circuit (not shown) for driving each switching element. The drive circuit may be built in the power semiconductor module 202 or may be provided outside the power semiconductor module 202. The drive circuit generates a drive signal for driving the switching element included in the main conversion circuit 201, and supplies the drive signal to the control electrode of the switching element of the main conversion circuit 201. Specifically, according to the control signal from the control circuit 203, a drive signal for turning on the switching element and a drive signal for turning off the switching element are output to the control electrodes of each switching element.

In the power conversion device 200 according to the present embodiment, the power semiconductor modules 1, 1b, 1c according to any one of the first to third embodiments are applied as the power semiconductor module 202 included in the main conversion circuit 201. Ru. Therefore, the power conversion device 200 according to the present embodiment has low cost and high reliability.

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

The power conversion device to which the present invention is applied is not limited to the case where the load is an electric motor, for example, a power supply device of an electric discharge machine or a laser machine machine, or an induction heating cooker or a non-contact power supply system. Can be incorporated into a power supply. The power conversion device to which the present invention is applied can be used as a power conditioner for a photovoltaic power generation system, a power storage system, or the like.

It should be considered that the embodiments 1-4 disclosed this time are exemplary in all respects and are not restrictive. As long as there is no contradiction, at least two of Embodiments 1-4 disclosed this time may be combined. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1,1b, 1c Power semiconductor module, 11 Insulated substrate, 12 Heat dissipation member, 13 Insulated resin sheet, 13a 1st surface, 13b 2nd surface, 13g crack, 14 Conductive circuit pattern, 18 Adhesive, 20 Electrode terminal, 21 1st main surface, 21a outer circumference, 22 2nd main surface, 23 uneven structure, 25 protrusions, 40 switching elements, 41 1st electrode, 42 2nd electrode, 43 3rd electrode, 45 freewheeling diode , 46 4th electrode, 47 5th electrode, 50 conductive bonding member, 55, 56, 57 conductive wire, 60 cushioning member, 60a outer circumference, 61 first bonding layer, 62 second bonding layer, 65 case. , 67 Sealing member, 70 Ultrasonic horn, 71 protrusion, 100 power supply, 200 power conversion device, 201 main conversion circuit, 202 power semiconductor module, 203 control circuit, 300 load.

Claims (15)

An insulating substrate including an insulating resin sheet and a conductive circuit pattern provided on the first surface of the insulating resin sheet.
A power semiconductor device bonded to the conductive circuit pattern via a conductive bonding member,
It is provided with an electrode terminal ultrasonically bonded to the conductive circuit pattern via a shock absorber.
The insulating resin sheet is thinner than the conductive circuit pattern,
The electrode terminal has a first main surface facing the cushioning member and a second main surface opposite to the first main surface, and the cushioning member has the conductive circuit pattern and the above-mentioned conductive circuit pattern. It consists of a material that has a lower yield strength and a lower melting point than the electrode terminals.
The electrode terminals are separated from the conductive circuit pattern .
The shock absorber is a power semiconductor module having a melting point of 250 ° C. or lower, which is a Sn—Cu based solder, a Sn—Ag based solder, a Sn—Ag—Cu based solder, or a Sn—Sb based solder . The power semiconductor module according to claim 1 , wherein the cushioning member has the same or lower melting point as the conductive joining member. The power semiconductor module according to claim 1 or 2 , wherein in the plan view of the conductive circuit pattern, all the outer circumferences of the shock absorber member are outside the outer circumference of the first main surface of the electrode terminal. 3. The second area of the cushioning member in the plan view of the conductive circuit pattern is larger than 100% and 110% or less of the first area of the first main surface of the electrode terminal. The power semiconductor module described in. The electrode terminals include one or more protrusions protruding from the first main surface.
The power semiconductor module according to any one of claims 1 to 4 , wherein the one or more protrusions are separated from the conductive circuit pattern. The power semiconductor module according to claim 5 , wherein each of the one or more protrusions has the shape of a polygonal prism, a polygonal pyramid, a cone, or a cylinder. The power semiconductor module according to claim 5 or 6 , wherein each of the one or more protrusions has a convex curved surface at the top thereof. Further equipped with a sealing member,
The sealing member is any of claims 1 to 7 , wherein the sealing member seals the power semiconductor element, the conductive circuit pattern, the cushioning member, and a part of the electrode terminal facing the cushioning member. The power semiconductor module according to claim 1. It comprises joining a power semiconductor device to a conductive circuit pattern via a conductive joining member.
The insulating substrate includes an insulating resin sheet and the conductive circuit pattern provided on the first surface of the insulating resin sheet, and further.
The electrode terminals are joined to the conductive circuit pattern via a cushioning member, and the electrode terminals have a first main surface facing the cushioning member and a second surface opposite to the first main surface. The cushioning member is made of a material having a conductive circuit pattern and a lower yield strength and a lower melting point than the electrode terminals.
To bond the electrode terminal to the conductive circuit pattern via the cushioning member, the cushioning member is stacked on the conductive circuit pattern, the electrode terminal is stacked on the cushioning member, and the second. The second main surface includes the ultrasonic bonding of the electrode terminal and the cushioning member by pressing an ultrasonic horn against the main surface of the surface and the bonding of the cushioning member and the conductive circuit pattern. By pressing the ultrasonic horn against the body, the buffer member undergoes a phase transition from a solid phase to a liquid phase.
A method for manufacturing a power semiconductor module, wherein the electrode terminals are separated from the conductive circuit pattern. The method for manufacturing a power semiconductor module according to claim 9 , wherein the cushioning member and the conductive circuit pattern are ultrasonically bonded by pressing the ultrasonic horn against the second main surface. To join the power semiconductor element to the conductive circuit pattern via the conductive joining member, the conductive joining member is stacked on the conductive circuit pattern and the power semiconductor is placed on the conductive joining member. It comprises stacking the elements and applying heat to join the power semiconductor device to the conductive circuit pattern via the conductive joining member.
The method for manufacturing a power semiconductor module according to claim 9 , wherein the cushioning member and the conductive circuit pattern are joined by applying the heat. The method for manufacturing a power semiconductor module according to any one of claims 9 to 11 , wherein the shock absorber has a melting point of 250 ° C. or lower. The method for manufacturing a power semiconductor module according to any one of claims 9 to 12 , wherein the cushioning member stacked on the conductive circuit pattern has a thickness of 0.2 mm or more. The electrode terminals include one or more protrusions protruding from the first main surface.
The method for manufacturing a power semiconductor module according to any one of claims 9 to 13 , wherein the one or more protrusions are separated from the conductive circuit pattern. A main conversion circuit having the power semiconductor module according to any one of claims 1 to 8 and converting and outputting input power.
A power conversion device including a control circuit that outputs a control signal for controlling the main conversion circuit to the main conversion circuit.

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