Method for manufacturing power module, power module, and heating device for manufacturing power module

Abstract

A method for manufacturing a power module comprises: a step of preparing a laminate including a substrate having a first electrode and a second electrode, a semiconductor element disposed on the first electrode via a first bonding layer, and a wiring member disposed on the semiconductor element via a second bonding layer and disposed on the second electrode via a third bonding layer; a first connection step of electrically connecting the first electrode and the semiconductor element; a second connection step of electrically connecting the semiconductor element and the wiring member; and a third connection step of electrically connecting the second electrode and the wiring member. The connection in the first connection step is performed by melting the first bonding layer by induction heating.

Description

Method for manufacturing a power module, power module, and heating device for manufacturing a power module

[0001] The present disclosure relates to a method for manufacturing a power module, a power module, and a heating device for manufacturing a power module.

[0002] Power modules are used in various fields such as automobiles, railways, power supply equipment, and industrial equipment. In addition to a base material and semiconductor elements mounted on the base material, a power module includes various members. Various configurations of the power module have been studied (see, for example, Patent Document 1 below).

[0003] Japanese Patent Application Laid-Open No. 2008-16564

[0004] In a conventional method for manufacturing a power module, a laminated structure before connecting members constituting the power module to each other by a bonding layer is placed in a high-temperature furnace, and the bonding layer is melted to connect the members to each other. When the laminated structure is heated in the high-temperature furnace, wiring members, bonding layers, etc. made of a metal material expand, while substrates, semiconductor elements, etc. hardly expand. Therefore, when heat is dissipated after connecting the members to each other, the members made of a metal material contract, but the other members hardly contract, so stress is generated due to the difference in the thermal contraction rate between the members. Such stress may cause cracking of the members, peeling of the bonding layer, and poor connection.

[0005] One aspect of the present disclosure aims to provide a method for manufacturing a power module that can suppress the generation of stress caused by the difference in the thermal contraction rate of each member when manufacturing the power module. Another aspect of the present disclosure aims to provide a power module and a heating device for manufacturing a power module.

[0006] One aspect of this disclosure includes, for example, the following [1] to

[30] : [1] A method for manufacturing a power module, comprising: a step of preparing a laminate comprising: a substrate having electrodes; a semiconductor element disposed on the electrodes via a first junction layer; and a wiring member disposed on the semiconductor element via a second junction layer; a first connection step of electrically connecting the electrodes and the semiconductor element via the first junction layer; and a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer, wherein the first connection step connects the electrodes and the semiconductor element by melting the first junction layer by induction heating. [2] A method for manufacturing a power module, comprising: a step of preparing a laminate comprising a substrate having electrodes; a semiconductor element disposed on the electrodes via a first junction layer; and a wiring member disposed on the semiconductor element via a second junction layer; a first connection step of electrically connecting the electrodes and the semiconductor element via the first junction layer; and a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer, wherein the second connection step connects the semiconductor element and the wiring member by melting the second junction layer by induction heating. [3] A method for manufacturing a power module, comprising: a step of preparing a laminate comprising a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and on the second electrode via a third junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; and a third connection step of electrically connecting the second electrode and the wiring member via the third junction layer, wherein the first connection step connects the first electrode and the semiconductor element by melting the first junction layer by induction heating.[4] A method for manufacturing a power module, comprising: a step of preparing a laminate comprising a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and on the second electrode via a third junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; and a third connection step of electrically connecting the second electrode and the wiring member via the third junction layer, wherein the second connection step connects the semiconductor element and the wiring member by melting the second junction layer by induction heating. [5] A method for manufacturing a power module, comprising: a step of preparing a laminate comprising a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and on the second electrode via a third junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; and a third connection step of electrically connecting the second electrode and the wiring member via the third junction layer, wherein the third connection step electrically connects the second electrode and the wiring member by melting the third junction layer by induction heating.[6] A method for manufacturing a power module, comprising: a step of preparing a laminate comprising: a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; a spacer disposed on the second electrode via a third junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and on the spacer via a fourth junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; a third connection step of electrically connecting the second electrode and the spacer via the third junction layer; and a fourth connection step of electrically connecting the spacer and the wiring member via the fourth junction layer, wherein the first connection step connects the first electrode and the semiconductor element by melting the first junction layer by induction heating. [7] A method for manufacturing a power module, comprising: a step of preparing a laminate comprising: a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; a spacer disposed on the second electrode via a third junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and on the spacer via a fourth junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; a third connection step of electrically connecting the second electrode and the spacer via the third junction layer; and a fourth connection step of electrically connecting the spacer and the wiring member via the fourth junction layer, wherein the second connection step connects the semiconductor element and the wiring member by melting the second junction layer by induction heating.[8] A method for manufacturing a power module, comprising: a step of preparing a laminate comprising: a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; a spacer disposed on the second electrode via a third junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and on the spacer via a fourth junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; a third connection step of electrically connecting the second electrode and the spacer via the third junction layer; and a fourth connection step of electrically connecting the spacer and the wiring member via the fourth junction layer, wherein the third connection step electrically connects the second electrode and the spacer by melting the third junction layer by induction heating. [9] A method for manufacturing a power module, comprising the steps of: preparing a laminate comprising a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; a spacer disposed on the second electrode via a third junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and on the spacer via a fourth junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; a third connection step of electrically connecting the second electrode and the spacer via the third junction layer; and a fourth connection step of electrically connecting the spacer and the wiring member via the fourth junction layer, wherein the fourth connection step electrically connects the spacer and the wiring member by melting the fourth junction layer by induction heating.

[10] The method for manufacturing a power module according to any one of [6] to [9], wherein the composition of the second junction layer is substantially the same as the composition of the fourth junction layer.

[11] The manufacturing method according to any one of [6] to

[10] , wherein the thickness of the second bonding layer is substantially the same as the thickness of the fourth bonding layer.

[12] The manufacturing method according to any one of [6] to

[11] , wherein the second bonding layer and the fourth bonding layer are formed of a paste-like bonding material.

[13] The manufacturing method according to any one of [6] to

[11] , wherein the second bonding layer and the fourth bonding layer are formed of a sheet-like bonding material.

[14] The manufacturing method according to any one of [3] to

[13] , wherein the thickness of the first bonding layer is substantially the same as the thickness of the third bonding layer.

[15] The manufacturing method according to any one of [3] to

[14] , wherein the composition of the first bonding layer is substantially the same as the composition of the third bonding layer.

[16] The manufacturing method according to any one of [3] to

[15] , wherein the first bonding layer and the third bonding layer are formed of a paste-like bonding material.

[17] The manufacturing method according to any one of [3] to

[16] , wherein the first bonding layer and the third bonding layer are formed of a sheet-like bonding material.

[18] The manufacturing method according to any one of [6] to

[17] , wherein at least one bonding layer selected from the group consisting of the first bonding layer, the second bonding layer, the third bonding layer, and the fourth bonding layer is a sintered body.

[19] A manufacturing method according to any one of [6] to

[18] , wherein at least one bonding layer selected from the group consisting of the first bonding layer, the second bonding layer, the third bonding layer, and the fourth bonding layer contains copper particles.

[20] A manufacturing method for a power module according to any one of [1] to

[19] , wherein the induction heating is low-frequency induction heating, and the laminate comprises a ferromagnetic material near or inside the bonding layer to be melted.

[21] A manufacturing method for a power module according to

[20] , wherein the ferromagnetic material contains Invar.

[22] A manufacturing method for a power module according to any one of [1] to

[21] , wherein the induction heating is performed while cooling the substrate from the side opposite to the side of the substrate on which the first electrode and the second electrode are arranged.

[23] A power module comprising: a substrate having electrodes; a semiconductor element connected to the electrodes via a first bonding layer; a wiring member connected to the semiconductor element via a second bonding layer; and a ferromagnetic material disposed near or inside at least one bonding layer selected from the group consisting of the first bonding layer and the second bonding layer.

[24] A power module comprising: a substrate having a first electrode and a second electrode; a semiconductor element connected to the first electrode via a first junction layer; a wiring member connected to the semiconductor element via a second junction layer and also connected to the second electrode via a third junction layer; and a ferromagnetic material disposed near or inside at least one junction layer selected from the group consisting of the first junction layer, the second junction layer, and the third junction layer.

[25] A power module comprising: a first substrate having a first electrode; a second substrate having a second electrode; a semiconductor element connected to the first electrode via a first junction layer; a wiring member connected to the semiconductor element via a second junction layer and also connected to the second electrode via a third junction layer; and a ferromagnetic material disposed near or inside at least one junction layer selected from the group consisting of the first junction layer, the second junction layer, and the third junction layer.

[26] The power module according to

[24] or

[25] , wherein the composition of the first junction layer is substantially the same as the composition of the third junction layer.

[27] A power module according to any one of

[24] to

[26] , wherein the thickness of the first bonding layer is substantially the same as the thickness of the third bonding layer.

[28] A power module according to any one of

[24] to

[27] , wherein at least one bonding layer selected from the group consisting of the first bonding layer, the second bonding layer, and the third bonding layer is a sintered body.

[29] A power module according to any one of

[24] to

[28] , wherein at least one bonding layer selected from the group consisting of the first bonding layer, the second bonding layer, and the third bonding layer contains copper particles.

[30] A heating device for manufacturing a power module, comprising: a chamber for housing a member to be heated; a coil section for generating an induced current inside the member to be heated by passing an electric current through it, thereby heating the member to be heated; a pressure control unit for adjusting the pressure inside the chamber; and an atmosphere control unit for adjusting the atmospheric gas inside the chamber.

[0007] According to one aspect of this disclosure, a method for manufacturing a power module can be provided that can suppress the generation of stress caused by differences in the thermal shrinkage rates of each component during the manufacturing of the power module. According to another aspect of this disclosure, a power module and a heating device for manufacturing a power module can be provided.

[0008] Figures 1(a) to 1(c) are cross-sectional views showing a method for manufacturing a power module according to one embodiment of the present disclosure. Figures 2(a) to 2(c) are cross-sectional views showing a method for manufacturing a power module according to one embodiment of the present disclosure, and show steps performed after the steps shown in Figure 1. Figures 3(a) to 3(c) are cross-sectional views showing a method for manufacturing a power module according to another embodiment of the present disclosure. Figures 4(a) and 4(b) are cross-sectional views showing a method for manufacturing a power module according to another embodiment of the present disclosure, and show steps performed after the steps shown in Figure 3. Figure 5 is a cross-sectional view showing an example of a power module according to one embodiment of the present disclosure. Figure 6 is a cross-sectional view showing an example of a power module according to another embodiment of the present disclosure.

[0009] The embodiments of this disclosure will be described below. However, this disclosure is not limited to the embodiments described below and can be implemented in various ways within the scope of its gist.

[0010] <Method for Manufacturing a Power Module> A method for manufacturing a power module according to one embodiment comprises the steps of: preparing a laminate (laminated laminate preparation step) comprising a substrate having electrodes, a semiconductor element disposed on the electrodes via a first junction layer, and a wiring member disposed on the semiconductor element via a second junction layer; a first connection step of electrically connecting the electrodes and the semiconductor element via the first junction layer; and a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer. In the first connection step, the electrodes and the semiconductor element may be electrically connected by melting the first junction layer by induction heating, and in the second connection step, the semiconductor element and the wiring member may be electrically connected by melting the second junction layer by induction heating. In the method for manufacturing a power module according to one embodiment, in either the first connection step or the second connection step, the junction layers are melted by induction heating to connect the members. The wiring member may be formed by plating.

[0011] A method for manufacturing a power module according to one embodiment includes a step of preparing a laminate (laminated laminate preparation step) comprising a substrate having a first electrode and a second electrode, a semiconductor element disposed on the first electrode via a first junction layer, and a wiring member disposed on the semiconductor element via a second junction layer and on the second electrode via a third junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via a first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via a second junction layer; and a third connection step of electrically connecting the second electrode and the wiring member via a third junction layer. The first connection step may be performed by melting the first junction layer by induction heating to electrically connect the first electrode and the semiconductor element, the second connection step may be performed by melting the second junction layer by induction heating to electrically connect the semiconductor element and the wiring member, and the third connection step may be performed by melting the third junction layer by induction heating to electrically connect the second electrode and the wiring member. In the method for manufacturing a power module according to one embodiment, in any of the first connection step, second connection step, and third connection step, the junction layers are melted by induction heating to connect the members. The following describes a method for manufacturing a power module according to one embodiment, with reference to the drawings.

[0012] As shown in Figures 1 and 2, the laminate preparation process may include, for example, the steps of preparing a substrate 10 having a first electrode 11 and a second electrode 12, placing a first junction layer 1 on the first electrode 11, placing a semiconductor element 20 on the first junction layer 1, placing a third junction layer 3 on the second electrode 12, placing a second junction layer 2 on the semiconductor element 20, and placing a wiring member 30 on the second junction layer 2 and the third junction layer 3. The laminate preparation process may further include the step of placing a ferromagnetic material on the wiring member 30. Each step may be performed in the order described above, in a different order, or some steps may be performed substantially simultaneously. The laminate preparation process may include, for example, the steps of preparing a substrate member such as a DBC substrate, placing a first junction layer on the first electrode and a third junction layer on the second electrode, and placing a semiconductor element on the first junction layer.

[0013] The constituent material of the substrate 10 may be ceramic. Examples of constituent materials for the insulating member include aluminum oxide, aluminum nitride, and silicon nitride. Examples of metallic elements constituting the metallic member include copper and aluminum.

[0014] A first electrode 11 and a second electrode 12 are arranged on the substrate 10. Hereinafter, the component on which the first electrode 11 and the second electrode 12 are arranged on the substrate 10 will also be referred to as the substrate component. The substrate component may be a DBC (Direct Bonded Copper) substrate, an AMB (Active Metal Brazed) substrate, a lead frame, etc.

[0015] The first electrode and the second electrode may be arranged on different substrates. If the first electrode and the second electrode are arranged on different substrates, the manufacturing method of the power module may include the steps of preparing a first substrate having the first electrode and preparing a second substrate having the second electrode in the laminate preparation step.

[0016] The first bonding layer 1, the second bonding layer 2, and the third bonding layer 3 (hereinafter collectively referred to as the "bonding layer" together with the fourth bonding layer 4 described later) may each be composed of the same material or of different materials. The constituent material of the bonding layer may be a metallic material. The metallic material may be a single metal or a metallic compound such as a metallic alloy. Examples of metallic elements constituting the bonding layer include copper, silver, gold, titanium, nickel, silicon, palladium, and aluminum. The bonding layer may be composed of a sintered body containing metal (metallic element) (for example, a sintered body of metal particles), or it may be a metallic layer formed by sintering and bonding metal particles. Examples of metal (metallic element) in such a sintered body include copper and silver. At least one bonding layer selected from the group consisting of the first bonding layer 1, the second bonding layer 2, and the third bonding layer 3 may be a sintered body from the viewpoint of electrical conductivity and heat dissipation. At least one bonding layer selected from the group consisting of a first bonding layer 1, a second bonding layer 2, and a third bonding layer 3 may contain at least one selected from the group consisting of solder, copper, and silver, and may also contain copper particles, from the viewpoint of electrical conductivity and heat dissipation.

[0017] The composition of the first bonding layer 1 may be substantially the same as the composition of the third bonding layer 3. Furthermore, the compositions of the first bonding layer 1, the second bonding layer 2, and the third bonding layer 3 may each be substantially the same.

[0018] The thickness of the first bonding layer 1 and the thickness of the second bonding layer 2 may be approximately the same.

[0019] At least one layer selected from the group consisting of a first bonding layer 1, a second bonding layer 2, and a third bonding layer 3 may be formed from a paste-like bonding material or from a sheet-like bonding material. The first bonding layer 1 and the third bonding layer 3 may be formed from a paste-like bonding material or from a sheet-like bonding material.

[0020] The constituent material of the wiring member 30 may be a metallic material. The metallic material may be a single metal or a metallic compound such as a metallic alloy. Examples of metallic elements constituting the wiring member 30 include copper, silver, gold, titanium, nickel, silicon, palladium, aluminum, and molybdenum.

[0021] The wiring member 30 may be wire-shaped or plate-shaped. The plate-shaped wiring member may be a flat plate-shaped wiring member, a stepped wiring member (for example, a clip wiring member), or a ribbon-shaped wiring member.

[0022] The first, second, and third connection steps may each include melting the bonding layer by heating and fusing the members in contact with the bonding layer. The first, second, and third connection steps may be independent steps or may be performed substantially simultaneously.

[0023] The connection in at least one step selected from the group consisting of a first connection step, a second connection step, and a third connection step is performed by melting at least one bonding layer selected from the group consisting of a first bonding layer 1, a second bonding layer 2, and a third bonding layer 3 by induction heating. Induction heating is a heating method in which an alternating current is passed through a coil (induction coil) to form a magnetic field around the coil, and by placing the coil that has formed the magnetic field near the bonding layer, an induced current is generated inside the bonding layer, and Joule heat is generated by the electrical resistance of the bonding layer.

[0024] The induction heating may be high-frequency induction heating or low-frequency induction heating. If the induction heating is low-frequency induction heating, the laminate may contain a ferromagnetic material near or inside the bonding layer to be melted. "Near the bonding layer" means close enough that the bonding layer can be heated by the Joule heat generated in the ferromagnetic material by low-frequency induction heating.

[0025] An example of a ferromagnetic material is Invar (an alloy of iron and nickel).

[0026] In the first, second, and third connection steps, heating in steps where induction heating is not used to connect the bonding layers may be performed by methods such as a high-temperature furnace or laser heating.

[0027] In the first connection step, the second connection step, and the third connection step, the bonding layer may be heated while cooling from the side opposite to the side of the substrate 10 where the first electrode 11 and the second electrode 12 are located.

[0028] In another embodiment, the method for manufacturing the power module may involve providing a laminate (second laminate) instead of the above-described laminate, comprising: a substrate 10 having a first electrode 11 and a second electrode 12; a semiconductor element 20 disposed on the first electrode 11 via a first bonding layer 1; a spacer 40 disposed on the second electrode 12 via a third bonding layer 3; and a wiring member 30 disposed on the semiconductor element 20 via a second bonding layer 2 and on the spacer 40 via a fourth bonding layer 4. In this case, the method for manufacturing the power module, as shown in Figures 3 to 4, comprises the steps of: preparing a laminate (second laminate preparation step) comprising: a substrate 10 having a first electrode 11 and a second electrode 12; a semiconductor element 20 disposed on the first electrode 11 via a first bonding layer 1; a spacer 40 disposed on the second electrode 12 via a third bonding layer 3; and a wiring member 30 disposed on the semiconductor element 20 via a second bonding layer 2 and on the spacer 40 via a fourth bonding layer 4; a first connection step of electrically connecting the first electrode 11 and the semiconductor element 20 via the first bonding layer 1; a second connection step of electrically connecting the semiconductor element 20 and the wiring member 30 via the second bonding layer 2; a third connection step of electrically connecting the second electrode 12 and the spacer 40 via the third bonding layer 3; and a fourth connection step of electrically connecting the spacer 40 and the wiring member 30 via the fourth bonding layer 4. The first connection step may involve melting the first bonding layer 1 by induction heating to connect the first electrode 11 and the semiconductor element 20; the second connection step may involve melting the second bonding layer 2 by induction heating to connect the semiconductor element 20 and the wiring member 30; the third connection step may involve melting the third bonding layer 3 by induction heating to electrically connect the second electrode 12 and the spacer 40; and the fourth connection step may involve melting the fourth bonding layer 4 by induction heating to electrically connect the spacer 40 and the wiring member 30. In one embodiment of the power module manufacturing method, in any of the first, second, third, and fourth connection steps, the bonding layers are melted by induction heating to connect the members.

[0029] The material used to construct the spacer 40 may be any electrically conductive material. The material used to construct the spacer 40 may be a metallic material. The metallic material may be a single metal or a metallic compound such as a metallic alloy. Examples of metallic elements that make up the spacer 40 include copper, silver, gold, titanium, nickel, silicon, palladium, aluminum, and molybdenum.

[0030] The thermal expansion coefficient of the spacer 40 may be smaller than that of the third bonding layer 3 and the fourth bonding layer 4. This can suppress connection failures caused by the wiring member 30 tilting relative to the substrate 10 after connection between the wiring member 30 and the second electrode 12. From the viewpoint of more effectively suppressing connection failures caused by the wiring member 30 tilting relative to the substrate 10, the thermal expansion coefficient of the spacer 40 may be approximately the same as that of the semiconductor element 20.

[0031] The thickness of the spacer 40 may be approximately the same as the thickness of the semiconductor element 20.

[0032] When viewed from the thickness direction of the substrate 10, the outer edge of the fourth bonding layer 4 may be located inside the outer edge of the spacer 40. By having the outer edge of the fourth bonding layer 4 located inside the outer edge of the spacer 40, it is possible to suppress the falling of a portion of the fourth bonding layer 4 onto the substrate 10, thereby suppressing the occurrence of a short circuit. From the viewpoint of suppressing the falling of a portion of the fourth bonding layer 4 onto the substrate 10, the thickness of the outer edge of the spacer 40 may be greater than the thickness of the region inside the outer edge of the spacer 40.

[0033] The constituent material of the fourth bonding layer 4 can be described by referring to the description of the constituent material of the bonding layer above. At least one bonding layer selected from the group consisting of the first bonding layer 1, the second bonding layer 2, the third bonding layer 3, and the fourth bonding layer 4 may be a sintered body from the viewpoint of electrical conductivity and heat dissipation. At least one bonding layer selected from the group consisting of the first bonding layer 1, the second bonding layer 2, the third bonding layer 3, and the fourth bonding layer 4 may contain at least one selected from the group consisting of solder, copper, and silver, and may also contain copper particles from the viewpoint of electrical conductivity and heat dissipation.

[0034] The composition of the second bonding layer 2 may be substantially the same as the composition of the fourth bonding layer 4. Furthermore, the compositions of the first bonding layer 1, the second bonding layer 2, the third bonding layer 3, and the fourth bonding layer 4 may each be substantially the same.

[0035] The thickness of the fourth bonding layer 4 may be approximately the same as the thickness of the second bonding layer 2. Also, the thicknesses of the first bonding layer 1, the second bonding layer 2, the third bonding layer 3, and the fourth bonding layer 4 may each be approximately the same.

[0036] The fourth bonding layer 4 may be formed from a paste-like bonding material or from a sheet-like bonding material. The second bonding layer 2 and the fourth bonding layer 4 may be formed from a paste-like bonding material or from a sheet-like bonding material.

[0037] The first, second, third, and fourth connection steps may each include melting the bonding layer by heating and fusing the members in contact with the bonding layer. The first, second, third, and fourth connection steps may each be independent steps or may be performed substantially simultaneously.

[0038] The connection in at least one step selected from the group consisting of a first connection step, a second connection step, a third connection step, and a fourth connection step is performed by melting at least one bonding layer selected from the group consisting of a first bonding layer 1, a second bonding layer 2, a third bonding layer 3, and a fourth bonding layer 4 by induction heating. In the first, second, third, and fourth connection steps, the heating in steps where the bonding layers are not connected by induction heating may be performed by methods such as a high-temperature furnace or laser heating. In the first, second, third, and fourth connection steps, the bonding layers may be heated while cooling from the side opposite to the surface on which the first electrode 11 and the second electrode 12 of the substrate 10 are located.

[0039] <Power Module> Another aspect of this disclosure relates to a power module. A power module according to one embodiment includes a substrate having electrodes, a semiconductor element connected to the electrodes via a first junction layer, a wiring member connected to the semiconductor element via a second junction layer, and a ferromagnetic material disposed near or inside at least one junction layer selected from the group consisting of the first junction layer and the second junction layer.

[0040] Furthermore, as shown in Figure 5, a power module 100 according to one embodiment includes a substrate 10 having a first electrode 11 and a second electrode 12, a semiconductor element 20 connected to the first electrode 11 via a first junction layer 1, a spacer 40 connected to the second electrode 12 via a third junction layer 3, a wiring member 30 connected to the semiconductor element 20 via a second junction layer 2 and also connected to the spacer 40 via a fourth junction layer 4, and a ferromagnetic material 50 disposed near or inside at least one junction layer selected from the group consisting of the first junction layer 1, the second junction layer 2, the third junction layer 3, and the fourth junction layer 4.

[0041] In the power module 100, the first electrode 11 may be directly connected to the first junction layer 1, the first junction layer 1 may be directly connected to the semiconductor element 20, the semiconductor element 20 may be directly connected to the second junction layer 2, the second junction layer 2 may be directly connected to the wiring member 30, the wiring member 30 may be directly connected to the fourth junction layer 4, the fourth junction layer 4 may be directly connected to the spacer 40, the spacer 40 may be directly connected to the third junction layer 3, and the third junction layer 3 may be directly connected to the second electrode 12. The power module 100 may have other members, bonding layers, etc., between the first electrode 11 and the first bonding layer 1, between the first bonding layer 1 and the semiconductor element 20, between the semiconductor element 20 and the second bonding layer 2, between the second bonding layer 2 and the wiring member 30, between the wiring member 30 and the fourth bonding layer 4, between the fourth bonding layer 4 and the spacer 40, between the spacer 40 and the third bonding layer 3, and between the third bonding layer 3 and the second electrode 12. The power module may not have a spacer, and the second electrode and the wiring member may be directly connected via a bonding layer.

[0042] The first electrode 11 and the second electrode 12 may each be on different substrates. That is, a power module 200 according to another embodiment of the present disclosure, as shown in Figure 6, comprises a first substrate 111 having the first electrode 11, a second substrate 112 having the second electrode 12, a semiconductor element 20 connected to the first electrode 11 via a first junction layer 1, a spacer 40 connected to the second electrode 12 via a third junction layer 3, a wiring member 30 connected to the semiconductor element 20 via a second junction layer 2 and also connected to the spacer 40 via a fourth junction layer 4, and a ferromagnetic material 50 disposed near or inside at least one junction layer selected from the group consisting of the first junction layer 1, the second junction layer 2, the third junction layer 3, and the fourth junction layer 4. The power module may not have a spacer, and the second electrode and the wiring member may be directly connected via a junction layer.

[0043] <Heating device for manufacturing power modules> Another aspect of the present disclosure relates to a heating device for manufacturing power modules that can be used in a method for manufacturing power modules. A heating device for manufacturing power modules according to one embodiment includes a chamber for housing a component to be heated, a coil section that generates an induced current inside the component to be heated by passing an electric current through it to heat the component, a pressure control unit for adjusting the pressure inside the chamber, and an atmosphere control unit for adjusting the atmospheric gas inside the chamber.

[0044] 1...First junction layer, 2...Second junction layer, 3...Third junction layer, 4...Fourth junction layer, 10...Substrate, 11...First electrode, 12...Second electrode, 20...Semiconductor element, 30...Wiring material, 40...Spacer, 50...Ferromagnetic material, 100, 200...Power module.

Claims

1. A method for manufacturing a power module, comprising: a step of preparing a laminate comprising a substrate having electrodes; a semiconductor element disposed on the electrodes via a first junction layer; and a wiring member disposed on the semiconductor element via a second junction layer; a first connection step of electrically connecting the electrodes and the semiconductor element via the first junction layer; and a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer, wherein the first connection step connects the electrodes and the semiconductor element by melting the first junction layer by induction heating.

2. A method for manufacturing a power module, comprising: a step of preparing a laminate comprising a substrate having electrodes; a semiconductor element disposed on the electrodes via a first junction layer; and a wiring member disposed on the semiconductor element via a second junction layer; a first connection step of electrically connecting the electrodes and the semiconductor element via the first junction layer; and a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer, wherein the second connection step connects the semiconductor element and the wiring member by melting the second junction layer by induction heating.

3. A method for manufacturing a power module, comprising: a step of preparing a laminate comprising: a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and also disposed on the second electrode via a third junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; and a third connection step of electrically connecting the second electrode and the wiring member via the third junction layer, wherein the first connection step connects the first electrode and the semiconductor element by melting the first junction layer by induction heating.

4. A method for manufacturing a power module, comprising: a step of preparing a laminate comprising a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and also disposed on the second electrode via a third junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; and a third connection step of electrically connecting the second electrode and the wiring member via the third junction layer, wherein the second connection step connects the semiconductor element and the wiring member by melting the second junction layer by induction heating.

5. A method for manufacturing a power module, comprising: a step of preparing a laminate comprising a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and also disposed on the second electrode via a third junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; and a third connection step of electrically connecting the second electrode and the wiring member via the third junction layer, wherein the third connection step electrically connects the second electrode and the wiring member by melting the third junction layer by induction heating.

6. A method for manufacturing a power module, comprising: a step of preparing a laminate comprising: a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; a spacer disposed on the second electrode via a third junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and on the spacer via a fourth junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; a third connection step of electrically connecting the second electrode and the spacer via the third junction layer; and a fourth connection step of electrically connecting the spacer and the wiring member via the fourth junction layer, wherein the first connection step connects the first electrode and the semiconductor element by melting the first junction layer by induction heating.

7. A method for manufacturing a power module, comprising: a step of preparing a laminate comprising: a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; a spacer disposed on the second electrode via a third junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and on the spacer via a fourth junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; a third connection step of electrically connecting the second electrode and the spacer via the third junction layer; and a fourth connection step of electrically connecting the spacer and the wiring member via the fourth junction layer, wherein the second connection step connects the semiconductor element and the wiring member by melting the second junction layer by induction heating.

8. A method for manufacturing a power module, comprising: a step of preparing a laminate comprising: a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; a spacer disposed on the second electrode via a third junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and on the spacer via a fourth junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; a third connection step of electrically connecting the second electrode and the spacer via the third junction layer; and a fourth connection step of electrically connecting the spacer and the wiring member via the fourth junction layer, wherein the third connection step electrically connects the second electrode and the spacer by melting the third junction layer by induction heating.

9. A method for manufacturing a power module, comprising: a step of preparing a laminate comprising: a substrate having a first electrode and a second electrode; a semiconductor element disposed on the first electrode via a first junction layer; a spacer disposed on the second electrode via a third junction layer; and a wiring member disposed on the semiconductor element via a second junction layer and on the spacer via a fourth junction layer; a first connection step of electrically connecting the first electrode and the semiconductor element via the first junction layer; a second connection step of electrically connecting the semiconductor element and the wiring member via the second junction layer; a third connection step of electrically connecting the second electrode and the spacer via the third junction layer; and a fourth connection step of electrically connecting the spacer and the wiring member via the fourth junction layer, wherein the fourth connection step electrically connects the spacer and the wiring member by melting the fourth junction layer by induction heating.

10. The manufacturing method according to any one of claims 6 to 9, wherein the composition of the second bonding layer is substantially the same as the composition of the fourth bonding layer.

11. The manufacturing method according to any one of claims 6 to 9, wherein the thickness of the second bonding layer is substantially the same as the thickness of the fourth bonding layer.

12. The manufacturing method according to any one of claims 6 to 9, wherein the second bonding layer and the fourth bonding layer are formed of a paste-like bonding material.

13. The manufacturing method according to any one of claims 6 to 9, wherein the second bonding layer and the fourth bonding layer are formed of a sheet-like bonding material.

14. The manufacturing method according to any one of claims 3 to 9, wherein the thickness of the first bonding layer is substantially the same as the thickness of the third bonding layer.

15. The manufacturing method according to any one of claims 3 to 9, wherein the composition of the first bonding layer is substantially the same as the composition of the third bonding layer.

16. The manufacturing method according to any one of claims 3 to 9, wherein the first bonding layer and the third bonding layer are formed of a paste-like bonding material.

17. The manufacturing method according to any one of claims 3 to 9, wherein the first bonding layer and the third bonding layer are formed of a sheet-like bonding material.

18. The manufacturing method according to any one of claims 6 to 9, wherein at least one bonding layer selected from the group consisting of the first bonding layer, the second bonding layer, the third bonding layer, and the fourth bonding layer is a sintered body.

19. The manufacturing method according to any one of claims 6 to 9, wherein at least one bonding layer selected from the group consisting of the first bonding layer, the second bonding layer, the third bonding layer, and the fourth bonding layer contains copper particles.

20. A method for manufacturing a power module according to any one of claims 1 to 9, wherein the induction heating is low-frequency induction heating, and the laminate comprises a ferromagnetic material near or inside the bonding layer to be melted.

21. The method for manufacturing a power module according to claim 20, wherein the ferromagnetic material contains Invar.

22. The method for manufacturing a power module according to any one of claims 3 to 9, wherein the induction heating is performed while cooling the substrate from the side opposite to the side of the substrate on which the first electrode and the second electrode are located.

23. A power module comprising: a substrate having electrodes; a semiconductor element connected to the electrodes via a first junction layer; a wiring member connected to the semiconductor element via a second junction layer; and a ferromagnetic material disposed near or inside at least one junction layer selected from the group consisting of the first junction layer and the second junction layer.

24. A power module comprising: a substrate having a first electrode and a second electrode; a semiconductor element connected to the first electrode via a first junction layer; a wiring member connected to the semiconductor element via a second junction layer and also connected to the second electrode via a third junction layer; and a ferromagnetic material disposed near or inside at least one junction layer selected from the group consisting of the first junction layer, the second junction layer, and the third junction layer.

25. A power module comprising: a first substrate having a first electrode; a second substrate having a second electrode; a semiconductor element connected to the first electrode via a first junction layer; a wiring member connected to the semiconductor element via a second junction layer and also connected to the second electrode via a third junction layer; and a ferromagnetic material disposed near or inside at least one junction layer selected from the group consisting of the first junction layer, the second junction layer, and the third junction layer.

26. The power module according to claim 24 or 25, wherein the composition of the first bonding layer is substantially the same as the composition of the third bonding layer.

27. The power module according to claim 24 or 25, wherein the thickness of the first bonding layer is substantially the same as the thickness of the third bonding layer.

28. The power module according to claim 24 or 25, wherein at least one bonding layer selected from the group consisting of the first bonding layer, the second bonding layer, and the third bonding layer is a sintered body.

29. The power module according to claim 24 or 25, wherein at least one bonding layer selected from the group consisting of the first bonding layer, the second bonding layer, and the third bonding layer contains copper particles.

30. A heating apparatus for manufacturing power modules, comprising: a chamber for housing a component to be heated; a coil section for generating an induced current inside the component to be heated by passing an electric current through it, thereby heating the component; a pressure control unit for adjusting the pressure inside the chamber; and an atmosphere control unit for adjusting the atmospheric gas inside the chamber.

Images