Power module and connecting member

Abstract

The present invention provides a power module equipped with connecting members capable of achieving excellent connection reliability while ensuring optimal electrical conductivity. [Solution] A power module 1 comprising a semiconductor element 10 and a connecting member 20, wherein the connecting member 20 comprises a first member 22, a conductive second member 24, and a third member 26, the first member 22 having a first main surface 22a and a second main surface 22b, the second member 24 being positioned on the first main surface 22a and having a main surface S1 that includes a connection region R1 in part, the third member 26 being positioned on the second main surface 22b, the thermal expansion coefficient of the first member 22 being smaller than that of the second member 24 and the third member 26, the electrical resistivity of the second member 24 being lower than that of the first member 22 and the third member 26, and the product of the thermal expansion coefficient and volume ratio of the second member 24 and the product of the thermal expansion coefficient and volume ratio of the third member 26 being substantially the same.

Description

【Technical Field】 【0001】 The present disclosure relates to a power module, a connection member, and the like. 【Background Art】 【0002】 Power modules are used in various fields such as automobiles, railways, power supply equipment, and industrial equipment. In a power module, a semiconductor element can be electrically connected to a connection target (for example, an external electrode) using a connection member. A power module using a wire as a connection member is known (for example, see Patent Document 1 below). 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 International Publication No. 2016 / 136457 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 In a power module, from the viewpoint of supplying a large current to a semiconductor element, it may be necessary to use a connection member different from a wire, and a connection member capable of achieving excellent connection reliability is required. In addition, for a connection member for electrically connecting a semiconductor element and a connection target, it is required to achieve excellent connection reliability while achieving suitable electrical conduction. 【0005】 One aspect of the present disclosure aims to provide a power module including a connection member for electrically connecting a semiconductor element and a connection target, the connection member being capable of achieving excellent connection reliability while achieving suitable electrical conduction. Another aspect of the present disclosure aims to provide a connection member for electrically connecting a semiconductor element and a connection target, the connection member being capable of achieving excellent connection reliability while achieving suitable electrical conduction. 【Means for Solving the Problems】 【0006】 The inventors focused on using a connecting member having a main surface that includes a region for electrical connection with a semiconductor element. However, with such a connecting member, the connecting member may expand or contract with temperature changes, which can cause problems such as poor connection between the semiconductor element and the connecting member. In response to this, the inventors have found that by using different materials for the second and third members in a connecting member comprising a first member having a first main surface and a second main surface opposite to the first main surface, a second member (a member having a main surface that includes a region for electrical connection between a semiconductor element and the connecting member) positioned on the first main surface, and a third member positioned on the second main surface, and by adjusting the physical properties of the first, second, and third members, it is possible to achieve excellent connection reliability while achieving suitable electrical conductivity. 【0007】 This disclosure relates to the following [1] to

[18] , etc. [1] A semiconductor element and a connecting member, the connecting member comprising a first member, a conductive second member and a third member, the first member having a first main surface on the semiconductor element side and a second main surface on the opposite side of the first main surface, the second member being positioned on the first main surface and having a main surface on the semiconductor element side that includes a region for electrically connecting the semiconductor element and the connecting member, the third member being positioned on the second main surface, and the first member A power module in which the coefficient of thermal expansion is smaller than that of the second and third members, the electrical resistivity of the second member is lower than that of the first and third members, the second and third members are formed from different materials, and the product of the coefficient of thermal expansion of the second member and the volume ratio of the second member to the entire connecting member, and the product of the coefficient of thermal expansion of the third member and the volume ratio of the third member to the entire connecting member are substantially the same. [2] The power module according to [1], wherein the first member is conductive. [3] The power module according to [1] or [2], wherein the first component contains at least one selected from the group consisting of iron and nickel. [4] The power module according to any one of [1] to [3], wherein the second member contains at least one selected from the group consisting of copper and aluminum. [5] A power module according to any one of [1] to [4], wherein the electrical resistivity of the first member is lower than the electrical resistivity of the third member. [6] The power module according to any one of [1] to [5], wherein the first main surface comprises a region on which the second member is arranged and a region on which the second member is not arranged. [7] The power module according to [6], wherein the second member has a plurality of portions extending substantially parallel to each other. [8] The power module according to any one of [1] to [7], wherein the second main surface comprises a region on which the third member is arranged and a region on which the third member is not arranged. [9] The power module according to [8], wherein the third member has a plurality of portions extending substantially parallel to each other.

[10] A connecting member used in a power module equipped with a semiconductor element, comprising a first member, a conductive second member, and a third member, wherein the first member has a first main surface on the semiconductor element side and a second main surface on the opposite side of the first main surface, the second member is disposed on the first main surface and has a main surface on the semiconductor element side that includes a region for electrically connecting the semiconductor element and the connecting member, and the third member is disposed on the second main surface, A connecting member wherein the thermal expansion coefficient of the first member is smaller than that of the second and third members, the electrical resistivity of the second member is lower than that of the first and third members, the second and third members are formed of different materials, and the product of the thermal expansion coefficient of the second member and the volume ratio of the second member to the entire connecting member, and the product of the thermal expansion coefficient of the third member and the volume ratio of the third member to the entire connecting member are substantially the same.

[11] The connecting member according to

[10] , wherein the first member is conductive.

[12] The connecting member according to

[10] or

[11] , wherein the first member contains at least one selected from the group consisting of iron and nickel.

[13] The connecting member according to any one of

[10] to

[12] , wherein the second member contains at least one selected from the group consisting of copper and aluminum.

[14] A connecting member according to any one of

[10] to

[13] , wherein the electrical resistivity of the first member is lower than the electrical resistivity of the third member.

[15] The connecting member according to any one of

[10] to

[14] , wherein the first main surface has a region on which the second member is arranged and a region on which the second member is not arranged.

[16] The connecting member according to

[15] , wherein the second member has a plurality of portions extending substantially parallel to each other.

[17] The connecting member according to any one of

[10] to

[16] , wherein the second main surface has a region on which the third member is arranged and a region on which the third member is not arranged.

[18] The connecting member according to

[17] , wherein the third member has a plurality of portions extending substantially parallel to each other. [Effects of the Invention] 【0008】 According to one aspect of this disclosure, a power module can be provided that includes a connecting member for electrically connecting a semiconductor element and a connected object, which is capable of achieving excellent connection reliability while achieving suitable electrical conductivity. According to another aspect of this disclosure, a connecting member for electrically connecting a semiconductor element and a connected object can be provided that is capable of achieving excellent connection reliability while achieving suitable electrical conductivity. [Brief explanation of the drawing] 【0009】 [Figure 1] Figure 1 is a schematic cross-sectional view showing an example of a power module. [Modes for carrying out the invention] 【0010】 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. 【0011】 In this specification, numerical ranges indicated using "~" represent a range that includes the numbers before and after "~" as the minimum and maximum values, respectively. "A or greater" in a numerical range means A and the range exceeding A. "A or less" in a numerical range means A and the range less than A. In numerical ranges described stepwise in this specification, the upper or lower limit of one step in the numerical range can be arbitrarily combined with the upper or lower limit of another step in the numerical range. Unless otherwise specified, the materials exemplified in this specification can be used individually or in combination of two or more. The term "layer" includes not only structural shapes formed across the entire surface when viewed in a plan view, but also structural shapes formed in part. 【0012】 The power module according to this embodiment comprises a semiconductor element and a connecting member, the connecting member comprising a first member, a conductive second member and a third member, the first member having a first main surface on the semiconductor element side and a second main surface on the opposite side of the first main surface, the second member being positioned on the first main surface and having a main surface on the semiconductor element side that includes a region for electrically connecting the semiconductor element and the connecting member, the third member being positioned on the second main surface, the thermal expansion coefficient of the first member being smaller than that of the second and third members, the electrical resistivity of the second member being lower than that of the first and third members, the second and third members being formed from different materials, and the product of the thermal expansion coefficient of the second member and the volume ratio of the second member to the entire connecting member, and the product of the thermal expansion coefficient of the third member and the volume ratio of the third member to the entire connecting member being substantially the same. 【0013】 The connecting member according to this embodiment is a connecting member used in a power module equipped with semiconductor elements. The connecting member according to this embodiment comprises a first member, a conductive second member, and a third member, wherein the first member has a first main surface on the semiconductor element side and a second main surface on the opposite side of the first main surface, the second member is positioned on the first main surface and has a main surface on the semiconductor element side that includes a region for electrically connecting the semiconductor element and the connecting member, the third member is positioned on the second main surface, the thermal expansion coefficient of the first member is smaller than that of the second and third members, the electrical resistivity of the second member is lower than that of the first and third members, the second and third members are formed from different materials, and the product of the thermal expansion coefficient of the second member and the volume ratio of the second member to the entire connecting member, and the product of the thermal expansion coefficient of the third member and the volume ratio of the third member to the entire connecting member are substantially the same. 【0014】 In the power module and connecting member according to this embodiment, the second member has a main surface on the semiconductor element side that includes a portion of a region for electrically connecting the semiconductor element and the connecting member (hereinafter referred to as the "first connection region"), and by electrically connecting the connecting member and the object to be connected via the region of the main surface other than the first connection region (hereinafter referred to as the "second connection region"), the semiconductor element and the object to be connected can be electrically connected via the connecting member. Furthermore, in the power module and connecting member according to this embodiment, the electrical resistivity of the second member is lower than that of the first and third members, thereby achieving suitable electrical conductivity (electrical conductivity between the semiconductor element and the object to be connected). 【0015】 In the power module and the connection member according to this embodiment, the coefficient of thermal expansion of the first member is smaller than those of the second and third members, and the product of the coefficient of thermal expansion of the second member and the volume ratio of the second member in the entire connection member, and the product of the coefficient of thermal expansion of the third member and the volume ratio of the third member in the entire connection member are substantially the same as each other. In this case, even if the connection member expands and contracts with temperature changes, the strains in the second and third members facing each other via the first member do not differ significantly, so that excessive strain in the connection member is suppressed. As a result, problems such as poor connection between the semiconductor element and the connection member are suppressed, and excellent connection reliability can be achieved. 【0016】 The power module according to this embodiment includes a semiconductor element and the connection member according to this embodiment. The power module according to this embodiment may include a single semiconductor element and may include a single connection member. The power module according to this embodiment may include a plurality of semiconductor elements and may include a plurality of connection members. 【0017】 The semiconductor element may contain silicon atoms and may contain a silicon compound (for example, silicon carbide). The semiconductor element may have a first main surface located on the connection member side and a second main surface (a main surface facing the first main surface) opposite to the connection member. The first main surface is located closer to the connection member side than the second main surface. The first main surface can be electrically connected to the first connection region in the second member. 【0018】 The connection member according to this embodiment includes a first member, a second member having conductivity, and a third member. The shapes of the connection member, the first member, the second member, and the third member are not particularly limited. At least one selected from the group consisting of the first member, the second member, and the third member may be layered. The connection member may be long (may extend in one direction). At least one selected from the group consisting of the first member, the second member, and the third member may be long (may extend in one direction). 【0019】 The first component may be conductive or insulating. The first component may contain inorganic materials or organic materials. The first component may contain conductive materials or metallic materials. The metallic material may contain elemental metals, metallic alloys, or metallic compounds. Examples of metallic elements in the metallic material include iron, nickel, aluminum, copper, silver, gold, titanium, palladium, cobalt, chromium, platinum, etc. The first component may contain at least one selected from the group consisting of iron and nickel, an alloy containing at least one selected from the group consisting of iron and nickel, an alloy containing iron and nickel, or Invar (Invar alloy). The first component does not have to contain copper. The first component may contain insulating materials, ceramics, or resin materials. Examples of ceramics include aluminum oxide, aluminum nitride, and silicon nitride. The constituent materials of the first member may be one type alone or a combination of two or more types. The first member may be formed solely of metallic materials, ceramics, or organic materials, or it may be formed of at least one material selected from the group consisting of metallic materials, ceramics, and organic materials. The first member may contain materials other than carbon materials, or it may not contain carbon materials. 【0020】 The first member has a first main surface on the semiconductor element side (the second member side) and a second main surface (a main surface facing the first main surface) on the opposite side of the first main surface (the third member side). The first main surface is located closer to the semiconductor element than the second main surface. The areas of the first and second main surfaces of the first member may be larger than the area of ​​the first main surface of the semiconductor element. 【0021】 The average thickness of the first member may be 0.1 μm or more, 0.5 μm or more, 1 μm or more, 3 μm or more, 5 μm or more, 8 μm or more, 10 μm or more, 12 μm or more, 15 μm or more, 18 μm or more, 20 μm or more, 30 μm or more, 50 μm or more, 80 μm or more, 100 μm or more, 150 μm or more, 200 μm or more, 300 μm or more, 500 μm or more, or 1000 μm or more. The average thickness of the first member may be 1000 μm or less, 500 μm or less, 300 μm or less, 200 μm or less, 150 μm or less, 100 μm or less, 80 μm or less, 50 μm or less, 30 μm or less, 20 μm or less, 18 μm or less, 15 μm or less, 12 μm or less, 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, 1 μm or less, 0.5 μm or less, or 0.1 μm or less. From these viewpoints, the average thickness of the first member may be between 0.1 and 1000 μm. As the average thickness of the first member, the average value of the thickness at 10 points on the first member can be used. 【0022】 The second component is electrically conductive. The second component may contain a metallic material. The metallic material may contain elemental metals, metal alloys, or metal compounds. Examples of metallic elements in the metallic material include iron, nickel, aluminum, copper, silver, gold, titanium, palladium, cobalt, chromium, and platinum. The second component may contain at least one selected from the group consisting of copper and aluminum. The constituent materials of the second component can be used individually or in combination of two or more. 【0023】 The second member is positioned on the first main surface of the first member and is in contact with the first member. 【0024】 The second member has a main surface S1 on the semiconductor element side that includes a first connection region for electrically connecting the semiconductor element and the connecting member. In the power module according to this embodiment, the first connection region is electrically connected to the semiconductor element. The main surface S1 may include a second connection region, distinct from the first connection region, for electrically connecting the connecting member and the object to be connected. In the power module according to this embodiment, the second connection region may be exposed before connection to the object to be connected and may be in contact with the object to be connected after connection. The second member may have a main surface S2 (a main surface facing the main surface S1) that is in contact with the first main surface of the first member on the side opposite to the main surface S1. 【0025】 The position and occupied area of ​​the first and second connection regions on the main surface S1 are not particularly limited. The first connection region may be located at one end of the elongated second member, or it may be located away from one end of the elongated second member. The second connection region may be located at the other end of the elongated second member, or it may be located away from the other end of the elongated second member. 【0026】 The average thickness of the second member may be 0.1 μm or more, 0.5 μm or more, 1 μm or more, 3 μm or more, 5 μm or more, 8 μm or more, 10 μm or more, 12 μm or more, 15 μm or more, 18 μm or more, 20 μm or more, 30 μm or more, 50 μm or more, 80 μm or more, 100 μm or more, 150 μm or more, 200 μm or more, 300 μm or more, 500 μm or more, or 1000 μm or more. The average thickness of the second member may be 1000 μm or less, 500 μm or less, 300 μm or less, 200 μm or less, 150 μm or less, 100 μm or less, 80 μm or less, 50 μm or less, 30 μm or less, 20 μm or less, 18 μm or less, 15 μm or less, 12 μm or less, 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, 1 μm or less, 0.5 μm or less, or 0.1 μm or less. From these viewpoints, the average thickness of the second member may be between 0.1 and 1000 μm. As the average thickness of the second member, the average value of the thickness at 10 locations on the second member can be used. The average thickness of the second member may be less than the average thickness of the first member. 【0027】 The second and third members are formed from different materials. That is, the compositions of the second and third members are different, and the second and third members may contain different components, or they may contain the same components but with different content (proportion) of those components. At least one selected from the group consisting of the second and third members does not need to contain fibers. 【0028】 The third component may be conductive or insulating. The third component may contain inorganic materials or organic materials. The third component may contain conductive materials or metallic materials. If the second component contains metallic materials, the third component may contain metallic materials different from those of the second component. The metallic materials may include elemental metals, metal alloys, or metal compounds. Examples of metallic elements in the metallic materials include iron, nickel, aluminum, copper, silver, gold, titanium, palladium, cobalt, chromium, platinum, etc. The third component may contain metallic materials with a higher electrical resistivity than the metallic materials in the second component. The third component may contain insulating materials, ceramics, or resin materials. Examples of ceramics include aluminum oxide, aluminum nitride, and silicon nitride. The constituent materials of the third component can be used individually or in combination of two or more types. 【0029】 The third member is positioned on the second main surface of the first member and is in contact with the first member. 【0030】 The average thickness of the third member may be 0.1 μm or more, 0.5 μm or more, 1 μm or more, 3 μm or more, 5 μm or more, 8 μm or more, 10 μm or more, 12 μm or more, 15 μm or more, 18 μm or more, 20 μm or more, 30 μm or more, 50 μm or more, 80 μm or more, 100 μm or more, 150 μm or more, 200 μm or more, 300 μm or more, 500 μm or more, or 1000 μm or more. The average thickness of the third member may be 1000 μm or less, 500 μm or less, 300 μm or less, 200 μm or less, 150 μm or less, 100 μm or less, 80 μm or less, 50 μm or less, 30 μm or less, 20 μm or less, 18 μm or less, 15 μm or less, 12 μm or less, 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, 1 μm or less, 0.5 μm or less, or 0.1 μm or less. From these viewpoints, the average thickness of the third member may be between 0.1 and 1000 μm. As the average thickness of the third member, the average value of the thickness at 10 points on the third member can be used. The average thickness of the third member may be less than the average thickness of the first member. 【0031】 The thermal expansion coefficient of the first member is smaller than that of the second and third members. The thermal expansion coefficient of the second member may be less than or equal to that of the third member, smaller than or equal to that of the third member, larger than or equal to that of the third member, or larger than that of the third member. The thermal expansion coefficients of the first, second, and third members may be the average thermal expansion coefficients at 25 to 150°C (heating rate: 5°C / min). The thermal expansion coefficient of each member can be adjusted depending on the type of material that constitutes each member. 【0032】 The electrical resistivity of the second component is lower than that of the first and third components. The electrical resistivity of the first component may be less than or equal to that of the third component, lower than or equal to that of the third component, higher than or equal to that of the third component, and higher than that of the third component. The electrical resistivity of each component can be adjusted by the type of material that constitutes each component, the thickness of each component, etc. 【0033】 The product A, which is the thermal expansion coefficient of the second member and the volume ratio of the second member to the entire connecting member, and the product B, which is the thermal expansion coefficient of the third member and the volume ratio of the third member to the entire connecting member, are approximately the same. Being approximately the same means that A and B are identical values, or that the ratio of the difference between A and B to the larger of the two products is 20% or less. From the viewpoint of easily obtaining excellent connection reliability, the ratio of the difference between A and B to the larger of the two products may be 15% or less, 10% or less, 5% or less, 3% or less, 2% or less, or 1% or less. 【0034】 At least one of the group consisting of the second and third members may be patterned. This allows for adjustment of the volume ratio of each member in the overall connecting member. The first main surface of the first member may have a region where the second member is located and a region where the second member is not located. For example, the second member may have a plurality of parts extending substantially parallel to each other, and the first member may be exposed between the plurality of parts. The plurality of parts of the second member may extend in the longitudinal direction of the long first member, or in a direction intersecting (e.g., perpendicular) the longitudinal direction of the long first member. The second main surface of the first member may have a region where the third member is located and a region where the third member is not located. For example, the third member may have a plurality of parts extending substantially parallel to each other, and the first member may be exposed between the plurality of parts. Multiple portions of the third member may extend in the longitudinal direction of the long first member, or in a direction intersecting (e.g., perpendicular to) the longitudinal direction of the long first member. 【0035】 The connecting member according to this embodiment may be obtained by rolling a laminate in which the first member is positioned between the second member and the third member. If it is difficult to roll the first member (for example, if the first member contains ceramic), the first member may be formed after the second member or the third member has been rolled. If it is difficult to roll the third member (for example, if the third member contains ceramic), the third member may be formed after the laminate comprising the first member and the second member has been rolled, or the first member and the third member may be formed after the second member has been rolled. 【0036】 The power module according to this embodiment may include a metal member A (for example, a layered metal member) that contacts the semiconductor element between the semiconductor element and the connecting member. The power module according to this embodiment may also include a metal member B (for example, a layered metal member) that contacts the semiconductor element on the side opposite to the connecting member. At least one metal material selected from the group consisting of metal member A and metal member B may include elemental metals, metal alloys, or metal compounds. Examples of metal elements in the metal material include copper, silver, gold, titanium, nickel, silicon, palladium, and aluminum. 【0037】 The power module according to this embodiment may include a metal member C (for example, a layered metal member) in contact with a second member of the connecting member between the semiconductor element and the connecting member. The metal member C may be in contact with the metal member A. The metal material of the metal member C may include elemental metals, metal alloys, or metal compounds. Examples of metal elements in the metal material include copper, silver, gold, titanium, nickel, silicon, palladium, and aluminum. The metal member C may be a sintered body containing metal (metal element). The sintered body may be porous. Examples of metal (metal element) in the sintered body include copper and silver. The metal member C may contain at least one selected from the group consisting of copper and silver, or it may be a sintered body containing at least one selected from the group consisting of copper and silver. 【0038】 The power module according to this embodiment may include a base material. The base material can support various components such as semiconductor elements. The base material may support a single semiconductor element or a plurality of semiconductor elements. The base material may be composed of a single component or a plurality of components. The base material may have an insulating member and a metal member D1 (for example, a layered metal member) disposed on the semiconductor element side relative to the insulating member. In this case, the insulating member and the metal member D1 may be in contact. The base material may have an insulating member, a metal member D1 (for example, a layered metal member) disposed on the semiconductor element side relative to the insulating member, and a metal member D2 (for example, a layered metal member) disposed on the opposite side of the insulating member from the semiconductor element. In this case, the insulating member may be in contact with at least one selected from the group consisting of metal member D1 and metal member D2. The insulating member may contain ceramic. Examples of constituent materials for the insulating member include aluminum oxide, aluminum nitride, silicon nitride, etc. Examples of metal elements constituting at least one selected from the group consisting of metal member D1 and metal member D2 include copper, aluminum, etc. The base material is indirectly connected to the second member of the connecting member via a first connection region on the main surface S1 of the second member. The base material may be indirectly connected to the second member only via the first connection region on the main surface S1, and may not be indirectly connected to the second member via a region other than the first connection region on the main surface S1. 【0039】 The power module according to this embodiment may include a metal member E (for example, a layered metal member) in contact with the substrate (for example, a metal member D1 of the substrate) between the semiconductor element and the substrate. The metal member E may be in contact with the metal member B. The metal material of the metal member E may contain elemental metals, metal alloys, or metal compounds. Examples of metal elements in the metal material include copper, silver, gold, titanium, nickel, silicon, palladium, and aluminum. The metal member E may be a sintered body containing metal (metal element). The sintered body may be porous. Examples of metal (metal element) in the sintered body include copper and silver. The metal member E may contain at least one selected from the group consisting of copper and silver, or it may be a sintered body containing at least one selected from the group consisting of copper and silver. 【0040】 The power module according to this embodiment may include a connection target that is electrically connected to a semiconductor element via a connecting member. The connection target may be, for example, an external electrode. The connection target may be elongated (extending in one direction). If the connecting member and the connection target are elongated, the longitudinal directions of the connecting member and the connection target may be the same direction or different directions (intersecting directions). 【0041】 The power module according to this embodiment may include a metal member F (for example, a layered metal member) that is in contact with the connecting member and the object to be connected between the connecting member and the object to be connected. The metal material of the metal member F may include elemental metals, metal alloys, or metal compounds. Examples of metal elements in the metal material include copper, silver, gold, titanium, nickel, silicon, palladium, and aluminum. The metal member F may be a sintered body containing metal (metal element). The sintered body may be porous. Examples of metal (metal element) in the sintered body include copper and silver. The metal member F may contain at least one selected from the group consisting of copper and silver, or it may be a sintered body containing at least one selected from the group consisting of copper and silver. 【0042】 Figure 1 is a schematic cross-sectional view showing an example of a power module. The power module 1 in Figure 1 comprises a semiconductor element 10, a connecting member 20, a base material 30, an external electrode (to be connected) 40, and metal members A, B, C, E, F. 【0043】 The connecting member 20 comprises a first member 22, a conductive second member 24, and a third member 26. The first member 22, the second member 24, and the third member 26 are layered, elongated members extending in one direction. The first member 22 has a first main surface 22a on the semiconductor element 10 side and a second main surface 22b on the opposite side of the first main surface 22a. The second member 24 is positioned on the first main surface 22a. The second member 24 has a main surface S1 on the semiconductor element 10 side that includes a connection region (first connection region) R1 for electrically connecting the semiconductor element 10 and the connecting member 20, and a connection region (second connection region) R2 for electrically connecting the connecting member 20 and the external electrode 40, and has a main surface S2 on the opposite side of the main surface S1 that is in contact with the first main surface 22a of the first member 22. The connection region R1 is located at one end of the second member 24. The connection region R2 is located at the other end of the second member 24. The third member 26 is positioned on the second main surface 22b. 【0044】 The thermal expansion coefficient of the first member 22 is smaller than that of the second member 24 and the third member 26. The electrical resistivity of the second member 24 is lower than that of the first member 22 and the third member 26. The second member 24 and the third member 26 are made of different materials. The product of the thermal expansion coefficient of the second member 24 and the volume ratio of the second member 24 to the entire connecting member 20, and the product of the thermal expansion coefficient of the third member 26 and the volume ratio of the third member 26 to the entire connecting member 20 are approximately the same. 【0045】 Metal member A is in contact with the semiconductor element 10 between the semiconductor element 10 and the connecting member 20. Metal member B is in contact with the semiconductor element 10 on the side opposite to the connecting member 20. Metal member C is in contact with the second member 24 (connection region R1) of the connecting member 20 and metal member A between the semiconductor element 10 and the connecting member 20. The base material 30 supports various members such as the semiconductor element 10. The base material 30 has an insulating member 32, a metal member D1 that is in contact with the insulating member 32 on the semiconductor element 10 side of the insulating member 32, and a metal member D2 that is in contact with the insulating member 32 on the side opposite to the semiconductor element 10. Metal member E is in contact with metal member B and metal member D1 of the base material 30 between the semiconductor element 10 and the base material 30. Metal member F is in contact with the connecting member 20 (connection region R2) and the external electrode 40 between the connecting member 20 and the external electrode 40. [Explanation of Symbols] 【0046】 1...Power module, 10...Semiconductor element, 20...Connecting member, 22...First member, 22a...First main surface, 22b...Second main surface, 24...Second member, 26...Third member, 30...Base material, 32...Insulating member, 40...External electrode (to be connected), A, B, C, D1, D2, E, F...Metal members, R1, R2...Connection area, S1, S2...Main surface.

Claims

[Claim 1] It comprises a semiconductor element and a connecting member, The connecting member comprises a first member, a second member having conductivity, and a third member. The first member has a first main surface on the semiconductor element side and a second main surface on the opposite side of the first main surface. The second member is arranged on the first main surface and has a main surface on the semiconductor element side that includes a region for electrically connecting the semiconductor element and the connecting member. The third member is arranged on the second main surface, The thermal expansion coefficient of the first member is smaller than that of the second member and the third member. The electrical resistivity of the second member is lower than that of the first member and the third member. The second member and the third member are formed from different materials. A power module in which the product of the thermal expansion coefficient of the second member and the volume ratio of the second member to the entire connecting member, and the product of the thermal expansion coefficient of the third member and the volume ratio of the third member to the entire connecting member, are substantially the same. [Claim 2] The power module according to claim 1, wherein the first member is conductive. [Claim 3] The power module according to claim 1, wherein the first member contains at least one selected from the group consisting of iron and nickel. [Claim 4] The power module according to claim 1, wherein the second member contains at least one selected from the group consisting of copper and aluminum. [Claim 5] The power module according to claim 1, wherein the electrical resistivity of the first member is lower than the electrical resistivity of the third member. [Claim 6] The power module according to any one of claims 1 to 5, wherein the first main surface has a region on which the second member is arranged and a region on which the second member is not arranged. [Claim 7] The power module according to claim 6, wherein the second member has a plurality of portions extending substantially parallel to each other. [Claim 8] The power module according to any one of claims 1 to 5, wherein the second main surface has a region on which the third member is arranged and a region on which the third member is not arranged. [Claim 9] The power module according to claim 8, wherein the third member has a plurality of portions extending substantially parallel to each other. [Claim 10] A connecting member used in a power module equipped with semiconductor elements, It comprises a first member, a second member having conductivity, and a third member. The first member has a first main surface on the semiconductor element side and a second main surface on the opposite side of the first main surface. The second member is arranged on the first main surface and has a main surface on the semiconductor element side that includes a region for electrically connecting the semiconductor element and the connecting member. The third member is arranged on the second main surface, The thermal expansion coefficient of the first member is smaller than that of the second member and the third member. The electrical resistivity of the second member is lower than that of the first member and the third member. The second member and the third member are formed from different materials. A connecting member in which the product of the thermal expansion coefficient of the second member and the volume ratio of the second member to the entire connecting member, and the product of the thermal expansion coefficient of the third member and the volume ratio of the third member to the entire connecting member, are substantially the same. [Claim 11] The connecting member according to claim 10, wherein the first member is electrically conductive. [Claim 12] The connecting member according to claim 10, wherein the first member contains at least one selected from the group consisting of iron and nickel. [Claim 13] The connecting member according to claim 10, wherein the second member contains at least one selected from the group consisting of copper and aluminum. [Claim 14] The connecting member according to claim 10, wherein the electrical resistivity of the first member is lower than the electrical resistivity of the third member. [Claim 15] The connecting member according to any one of claims 10 to 14, wherein the first main surface has a region on which the second member is arranged and a region on which the second member is not arranged. [Claim 16] The connecting member according to claim 15, wherein the second member has a plurality of portions extending substantially parallel to each other. [Claim 17] The connecting member according to any one of claims 10 to 14, wherein the second main surface has a region on which the third member is arranged and a region on which the third member is not arranged. [Claim 18] The connecting member according to claim 17, wherein the third member has a plurality of portions that extend substantially parallel to each other.

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