JP6460160B2 - Electrical connection member, electrical connection structure, and method of manufacturing electrical connection member - Google Patents

Description

  The present invention relates to an electrical connection member, an electrical connection structure using the electrical connection member, and a method for manufacturing the electrical connection member.

  Conventionally, a power module using an electrical connection member for electrically connecting one connection target member and another connection target member is known (see, for example, Patent Document 1).

  Patent Document 1 discloses a power module including a lead frame, a semiconductor chip disposed on the lead frame, and an aluminum wire that electrically connects the lead frame and the semiconductor chip. In this power module, the lead frame and the semiconductor chip are electrically connected by ultrasonic welding of an aluminum wire to the surface on which the semiconductor chip of the lead frame having a different height is placed and the upper surface of the semiconductor chip. It is connected to the. The semiconductor chip and the aluminum wire are resin-molded in a state where the lead frame and the semiconductor chip are electrically connected by the aluminum wire.

Japanese Patent Laying-Open No. 2015-23211

  However, in the power module of Patent Document 1, an aluminum wire made of metal (Al) having a large thermal expansion coefficient tends to expand due to heat generated during energization. Here, since the aluminum wire is fixed to the lead frame or the semiconductor chip (member to be connected) in the ultrasonic welding portion (electrical connection portion) and is fixed by the resin mold, the aluminum wire cannot be sufficiently thermally expanded. It is considered that stress resulting from the suppression of thermal expansion is applied to the ultrasonic welded portion. As a result, it is considered that there is a problem that damage such as cracks and peeling may occur in the ultrasonic welded portion. Note that this problem is particularly problematic in structures such as power modules that are prone to high temperatures due to the flow of high current. Also, in order to obtain sufficient connection strength, when connecting the aluminum wire and the lead frame or semiconductor chip by applying pressure, pressure cannot be applied evenly to the part to be connected due to the difference in height position. In addition, it is considered that there is a problem that the ultrasonic welding portion may be connected with insufficient connection strength.

  The present invention has been made in order to solve the above-described problems, and the object of the present invention is to sufficiently prevent the electrical connection portion from being damaged due to thermal expansion while sufficiently preventing the electrical connection portion from being damaged. It is to provide an electrical connection member that can be connected with an appropriate connection strength, an electrical connection structure using the electrical connection member, and a method of manufacturing the electrical connection member.

The electrical connection member according to the first aspect of the present invention includes a first Cu layer made of Cu or a Cu alloy, and an Fe alloy or Ni material having an average coefficient of thermal expansion from room temperature to 300 ° C. smaller than that of the first Cu layer. A clad material comprising a clad material in which a low thermal expansion layer configured and a second Cu layer composed of Cu or a Cu alloy are joined in this order are arranged on the opposite side of the low thermal expansion layer from the first Cu layer On the surface of the first Cu layer side, a first surface and a second surface that is connected to the first surface through a stepped portion and is located on the low thermal expansion layer side than the first surface are formed. and second surfaces has an electrical connection portion, and the cladding material of the thickness of the first surface is much larger than the thickness of the clad material of the second surface, the first surface-side cladding material thickness Low thermal expansion layer, first Cu layer and second C The ratio of the thickness of the layer, the low thermal expansion layer to the thickness of the clad material of the second surface side, substantially equal to the ratio of the thickness of the 1Cu layer and the 2Cu layer, The "Cu alloy", Cu (copper) Is an alloy containing 50 mass% or more as a main component, “Fe alloy” means an alloy containing Fe (iron) as a main component and 50 mass% or more, and “Ni material” is pure Ni (nickel) Or an alloy material containing Ni as a main component and containing 50% by mass or more.

  As described above, the electrical connection member according to the first aspect of the present invention includes a first Cu layer composed of Cu or a Cu alloy, and an Fe whose average thermal expansion coefficient from room temperature to 300 ° C. is smaller than that of the first Cu layer. A clad material joined at least to a low thermal expansion layer made of an alloy or Ni material is provided. This suppresses the thermal expansion of the first Cu layer composed of Cu or Cu alloy having a large thermal expansion by the low thermal expansion layer in the temperature range from room temperature to 300 ° C. which is the normal use environment of the electrical connection member. Can do. As a result, since the thermal expansion can be reduced in the entire clad material including the first Cu layer and the low thermal expansion layer, it is possible to suppress the stress caused by the thermal expansion from being applied to the electrical connection portion of the electrical connection member. can do. Therefore, it is possible to suppress the occurrence of damage such as cracks and peeling at the electrical connection portion due to the thermal stress. In addition, a first surface and a second surface that is connected to the first surface via the stepped portion and located on the low thermal expansion layer side than the first surface are formed on the surface of the clad material on the first Cu layer side. Thereby, even if there is a difference in height position (step) between one connection target member to which the electrical connection member is electrically connected and the other connection target member, the first Cu layer side of the clad material By the step portion formed on the surface, at least a part of the step between one connection target member and another connection target member can be absorbed. As a result, the influence of the step can be reduced, and it is possible to suppress the pressure from being uniformly applied due to the step, so that the electric connection member and the one connection target member (others) Can be connected with sufficient connection strength. As a result, the electrical connection portion can be connected with sufficient connection strength while suppressing the occurrence of damage to the electrical connection portion due to thermal expansion. Therefore, it is particularly effective to use the electrical connection member of the present invention in an electrical connection structure provided in a power module or the like that is likely to become hot when a high current flows.

  In the electrical connection member according to the first aspect, the cladding is connected to the surface of the clad material on the first Cu layer side via the first surface and the stepped portion, and has a lower thermal expansion layer than the first surface. And a second surface located on the side. As a result, when one connection target member and another connection target member are connected to the first Cu layer side of the electrical connection member, electricity (current) easily flows through the first Cu layer near the electrical connection portion. Since the flowing first Cu layer is made of Cu or Cu alloy having a low volume resistivity, power loss (power loss) during power transmission can be reduced.

  In the electrical connection member according to the first aspect, preferably, the surface of the cladding material opposite to the first Cu layer is formed in a flat surface shape having no stepped portion. In this case, the electrical connection member has a form in which the surface on the first Cu layer side of the clad material has two flat first surfaces and second surfaces adjacent to both sides of the stepped portion, and the first Cu of the clad material. The surface opposite to the layer side has a flat surface. If comprised in this way, when connecting one connection object member and another connection object member to the 1st Cu layer side of the member for electrical connection, from the surface on the opposite side to the 1st Cu layer of the flat clad material Easily apply pressure evenly. Thereby, in the electrical connection portion, the electrical connection member and the one connection target member (other connection target member) can be connected with more sufficient connection strength.

In member for electric connection according to the first aspect, clad material, and the first 1Cu layer of low thermal expansion layer is bonded to the opposite side, further comprising a first 2Cu layer composed of Cu or a Cu alloy. Also, the surface of the 2Cu layer side of the clad material is formed on the no step portion flat surface. In this case, the electrical connection member has a form in which the surface on the first Cu layer side of the clad material has two flat first surfaces and second surfaces adjacent to both sides of the stepped portion, and the second Cu of the clad material. The surface on the layer side is in the form of a flat surface. According to this structure, when the clad material is manufactured, the clad material warps due to the large ductility of the first Cu layer made of Cu or Cu alloy. Or it can suppress by the 2nd Cu layer comprised from a Cu alloy and joined to the opposite side to the 1st Cu layer of a low thermal expansion layer. Moreover, the volume resistivity of the member for electrical connection can be effectively reduced by providing the second Cu layer composed of Cu or Cu alloy having a low volume resistivity.

  In the electrical connection member according to the first aspect, preferably, the second surface side of the clad material is divided into a plurality along the extending direction of the stepped portion. If comprised in this way, since the several electrical connection part which protrudes in the direction which cross | intersects the direction where a level | step-difference part extends is formed in the several part divided | segmented in the 2nd surface side of a clad material, one electrical connection By the member for use, one connection object member arranged on the first surface side and a plurality of other connection object members arranged on the second surface side can be electrically connected. Thereby, one other connection object member arranged on the first surface side by one electrical connection member and one of the plurality of other connection object members arranged on the second surface side Compared with the case of electrical connection, the number of electrical connection members required for connection can be effectively reduced.

In the electrical connection member according to the first aspect, preferably, the low thermal expansion layer is made of an Fe alloy or Ni material having an average thermal expansion coefficient from room temperature to 300 ° C. of 15 × 10 ⁻⁶ / K or less. . If comprised in this way, the thermal expansion of the 1st Cu layer comprised from Cu or Cu alloy with large thermal expansion is a low thermal expansion layer whose average thermal expansion coefficient from room temperature to 300 degreeC is 15 * 10 < ^-6 > / K or less. Can be effectively suppressed. Thereby, it can suppress effectively that damage, such as a crack and peeling, arises in an electrical connection part. The average thermal expansion coefficient of the low thermal expansion layer from room temperature to 300 ° C. is 12 × 10 ⁻⁶ / K or less, 10 × 10 ⁻⁶ / K or less, 8 × 10 ⁻⁶ / K or less, 6 × 10 ^−6. If it is smaller than / K or less, the effect of suppressing thermal expansion of the electrical connection member is increased, which is preferable.

In the electrical connection member according to the first aspect, preferably , at least one of the electrical connection portion on the first surface and the electrical connection portion on the second surface is plated with Ag, Ag alloy, Ni, or Ni alloy. A layer is formed. If comprised in this way, when using the connection material which consists of metal materials, such as a brazing material, for the connection of the member for electrical connection, and a connection object member, the wettability of a connection material can be improved with a plating layer. Thereby, the member for electrical connection and the connection object member can be reliably connected by the connecting material.

  In this case, the plating layer is preferably formed on the entire surface of the clad material. If comprised in this way, unlike the case where a plating layer is formed only in a part of surface of a clad material, it is not necessary to form a mask, Therefore A plating layer can be formed easily. In addition, since the electrical connection portion can be secured over a wide range on the first surface and the second surface, the electrical connection member and the connection target member can be reliably and easily connected by the connection material. Furthermore, since Ag, Ag alloy, Ni or Ni alloy is excellent in corrosion resistance compared to Fe alloy and the like not containing Cu and Cr, the corrosion resistance of the clad material can be improved by the plating layer.

The electrical connection structure according to the second aspect of the present invention is composed of a first Cu layer composed of Cu or a Cu alloy, and an Fe alloy or Ni material having an average coefficient of thermal expansion from room temperature to 300 ° C. smaller than that of the first Cu layer. A clad material in which the low thermal expansion layer is disposed on the opposite side of the first Cu layer of the low thermal expansion layer and the second Cu layer composed of Cu or a Cu alloy is joined in this order . On the surface on the first Cu layer side, a first surface and a second surface connected to the first surface via a stepped portion and located on the low thermal expansion layer side than the first surface are formed. and second surfaces has an electrical connection portion, the clad material of the thickness of the first surface is much larger than the thickness of the clad material of the second surface, low heat to the cladding material of the thickness of the first surface Expansion layer, first Cu layer and second Cu The ratio of the thickness of the low thermal expansion layer to the second surface of the clad material thickness substantially equal to electric connecting member and the ratio of the thickness of the 1Cu layer and the 2Cu layer, the electrical connection of the first and second surfaces A connecting member for connecting the electrical connection member and the connection target member in the portion.

  In the electrical connection structure according to the second aspect of the present invention, similarly to the electrical connection member according to the first aspect, the electrical connection member and the connection target member are connected via the connection material due to thermal expansion. It is possible to obtain an electrical connection structure that is suppressed from being damaged at the electrical connection portion that is a portion to be connected and that is connected with sufficient connection strength at the electrical connection portion.

The method for manufacturing an electrical connection member according to the third aspect of the present invention includes a first Cu layer made of Cu or a Cu alloy by rolling joining, and an average thermal expansion coefficient from room temperature to 300 ° C. higher than that of the first Cu layer. A clad material is produced by producing a clad material at least joined with a low thermal expansion layer composed of a small Fe alloy or Ni material, and performing plastic working on the produced clad material after producing the clad material by rolling joining A first surface and a second surface that is connected to the first surface via a stepped portion and is located closer to the low thermal expansion layer than the first surface are formed on the surface of the first Cu layer.

  In the method for manufacturing an electrical connection member according to the third aspect of the present invention, in addition to the same effect as the electrical connection member according to the first aspect, by performing plastic working on the cladding material, On the surface on the first Cu layer side, the first surface and the second surface connected to the first surface via the stepped portion and located on the low thermal expansion layer side than the first surface can be easily formed. In addition, as a plastic working, means, such as a press and roll reduction, can be used, for example.

  In the method for manufacturing the electrical connection member according to the third aspect, preferably, after forming the first surface and the second surface, the unnecessary portion that flows when the first surface and the second surface are formed is cut. Remove. If comprised in this way, the dispersion | variation in the shape in the member for electrical connection can be made small.

  In the method for manufacturing the electrical connection member according to the third aspect, preferably, after forming the first surface and the second surface, the second surface side of the clad material is divided into a plurality along the direction in which the stepped portion extends. To do. If comprised in this way, one of the several connection object members arrange | positioned by the one electrical connection member on the 2nd surface side, and 1 other of the other one arrange | positioned on the 1st surface side Compared to the case where the connection target member is electrically connected, the number of members for electrical connection required for connection can be effectively reduced.

  In the method for manufacturing an electrical connection member according to the third aspect, preferably, the first Cu layer, the low thermal expansion layer, and the first Cu layer of the low thermal expansion layer are formed on a side opposite to the first Cu layer by rolling bonding. A clad material in which the second Cu layer to be formed is bonded is produced. If comprised in this way, at the time of manufacture of a clad material, it is Cu or the same Cu as a 1st Cu layer that a clad material warps due to the large ductility of the 1st Cu layer comprised from Cu or Cu alloy. It can suppress by the 2nd Cu layer comprised from a Cu alloy and joined to the opposite side to the 1st Cu layer of a low thermal expansion layer. Moreover, the volume resistivity of the member for electrical connection can be effectively reduced by providing the second Cu layer composed of Cu or Cu alloy having a low volume resistivity.

  According to the present invention, as described above, an electrical connection member that can be connected with sufficient connection strength at the electrical connection portion while suppressing damage to the electrical connection portion due to thermal expansion, An electrical connection structure using the electrical connection member and a method of manufacturing the electrical connection member can be provided.

It is the perspective view which showed the member for electrical connection by 1st Embodiment of this invention. FIG. 7 is a cross-sectional view taken along line 700-700 in FIG. It is the perspective view which showed the electrical connection structure by 1st Embodiment of this invention. FIG. 7 is a cross-sectional view taken along line 710-710 in FIG. It is a schematic diagram for demonstrating the manufacturing process of the member for electrical connection by 1st Embodiment of this invention. It is a schematic cross section for demonstrating a press process (before press) among the manufacturing processes of the member for electrical connection by 1st Embodiment of this invention. It is a schematic cross section for demonstrating a press process (after a press) among the manufacturing processes of the member for electrical connection by 1st Embodiment of this invention. It is a schematic cross section for demonstrating a trimming process among the manufacturing processes of the member for electrical connection by 1st Embodiment of this invention. It is a schematic cross section for demonstrating the manufacturing process of the electrical connection structure using the member for electrical connection by 1st Embodiment of this invention. It is the perspective view which showed the member for electrical connection by 2nd Embodiment of this invention. It is a model perspective view for demonstrating an etching process among the manufacturing processes of the member for electrical connection by 2nd Embodiment of this invention. It is the perspective view which showed the member for electrical connection by 3rd Embodiment of this invention. It is sectional drawing which showed the member for electrical connection by the modification of 3rd Embodiment of this invention. It is sectional drawing which showed the member for electrical connection by the modification of 1st Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, the structure of the electrical connection member 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

[Structure of electrical connection members]
The electrical connection member 1 according to the first embodiment of the present invention includes one connection target member (for example, the lead frame 2 shown in FIG. 3) and another connection target member (for example, the semiconductor element 3 shown in FIG. 3). It is a member for electrical connection. In addition, although the maximum length (maximum thickness) of the thickness direction (Z direction) of the member 1 for electrical connection can be set so that it may be suitable for the amount of energization etc., for example, it is 0.01 mm-2.0 mm, but this maximum thickness It is not limited to. For example, when applied to an application with a large energization amount such as a power module, it is preferable that the maximum length (maximum thickness) of the electrical connection member 1 is 0.1 mm or more and 1.0 mm or less.

  As shown in FIG. 1, the electrical connection member 1 is composed of a plate-like clad material 10. The clad material 10 is laminated and bonded to a low thermal expansion layer 11 made of a low thermal expansion Fe alloy or Ni material, and one surface 11a on one side (Z1 side) in the thickness direction (Z direction) of the low thermal expansion layer 11. This is a clad material 10 having a three-layer structure including a Cu layer 12 and a Cu layer 13 laminated and bonded to the other surface 11b on the other side (Z2 side) in the thickness direction of the low thermal expansion layer 11. The Cu layer 12 and the Cu layer 13 are made of Cu or Cu alloy. In addition, at the interface Ia between the low thermal expansion layer 11 and the Cu layer 12 and the interface Ib between the low thermal expansion layer 11 and the Cu layer 13, the elements constituting each other layer are diffused and bonded at the atomic level. The Cu layer 12 and the Cu layer 13 are examples of the “first Cu layer” and the “second Cu layer” in the claims, respectively.

The low thermal expansion layer 11 is made of an Fe alloy or Ni material having a smaller average thermal expansion coefficient from room temperature to 300 ° C. than Cu or Cu alloy constituting the Cu layer 12. Preferably, the low thermal expansion layer 11 is made of an Fe alloy having an average thermal expansion coefficient of 15 × 10 ⁻⁶ / K or less from room temperature (30 ° C.) to 300 ° C. In addition, the average thermal expansion coefficient from room temperature to 300 ° C. in C1020 (oxygen-free copper) as an example of Cu or Cu alloy is about 17 × 10 ⁻⁶ / K.

Examples of Fe alloys having an average thermal expansion coefficient from room temperature to 300 ° C. of 15 × 10 ⁻⁶ / K or less include, for example, Ni—Co—Fe alloys, Ni—Fe alloys, Ni—Cr—Fe alloys, and Ni—Cr. -Co-Fe alloys, or some ferritic stainless steels such as SUS410, SUS430, and SUS444 defined in JIS standards, are not limited to these Fe alloys.

Here, as the Ni—Co—Fe alloy, for example, 29 mass% Ni (nickel), 17 mass% Co (cobalt), a trace amount content, unavoidable impurities and 29Ni-17Co—Fe alloy composed of the remainder Fe, etc. Is mentioned. The average thermal expansion coefficient of the 29Ni-17Co—Fe alloy from room temperature to 300 ° C. is about 5 × 10 ⁻⁶ / K.

Further, as the Ni-Fe alloy, for example, 36 mass% of Ni, a trace content, 36 alloy composed of inevitable impurities and the balance Fe, and 42 mass% of Ni, trace content, inevitable impurities and the balance Fe consisting of 42 alloys Etc. The average thermal expansion coefficient of the 36 alloy from room temperature to 300 ° C. is about 2 × 10 ⁻⁶ / K or less.

Examples of the Ni—Cr—Fe alloy include an Fe alloy containing 42% by mass of Ni, 6% by mass of Cr (chromium), a trace content, inevitable impurities, and the balance Fe. The average thermal expansion coefficient of the Fe alloy having the above composition from room temperature to 300 ° C. is about 8 × 10 ⁻⁶ / K.

In addition, the Ni—Cr—Co—Fe alloy contains, for example, 29 mass% Ni, 4 mass% to 10 mass% Cr, 17 mass% Co, trace content, inevitable impurities, and the balance Fe. Fe alloy etc. are mentioned. The average thermal expansion coefficient of the Fe alloy having the above composition from room temperature to 300 ° C. is about 6 × 10 ⁻⁶ / K.

Moreover, some ferritic stainless steel is mentioned as Fe alloy. For example, the average thermal expansion coefficient of up to 300 ° C. from room temperature is about 10 × 10 ^-6 / K in the SUS410 is about 11 × 10 ^-6 / K in SUS430, about 10 in SUS444 × 10 ^-6 / K It is.

Examples of the Ni material include pure Ni and monel metal containing 30% by mass of Cu and the balance Ni. The average thermal expansion coefficient of pure Ni from room temperature to 300 ° C. is about 13 × 10 ⁻⁶ / K, and Monel metal is about 12 × 10 ⁻⁶ / K.

  The Fe alloy or Ni material of the low thermal expansion layer 11 can be appropriately selected according to the specifications of the electrical connection member 1 and the like. For example, when it is desired to improve the corrosion resistance of the low thermal expansion layer 11, the low thermal expansion layer 11 is preferably composed of an Fe alloy containing Cr or pure Ni. For example, when it is desired to sufficiently suppress the thermal expansion of the electrical connection member 1, the low thermal expansion layer 11 is preferably composed of 29Ni-17Co—Fe alloy and 36 alloy having a particularly small thermal expansion coefficient.

  The Cu layers 12 and 13 are made of Cu or Cu alloy having high electrical conductivity. As Cu constituting the Cu layers 12 and 13, C1000 such as C1020 (oxygen-free copper), C1100 (tough pitch copper) and C1220 (phosphorus deoxidized copper) defined in JIS H3100 can be used. Further, as a Cu alloy constituting the Cu layers 12 and 13, a C2000 system defined in JIS H3100 can be used.

  Thereby, when an electric current is passed through the electrical connection member 1, the electrical conductivity in the electrical connection member 1 is improved by the current flowing mainly in the Cu layer 12 located on the surface layer of the clad material 10. Yes.

  Here, in the first embodiment, the surface 14 on the Cu layer 12 side (Z1 side) of the clad material 10 is connected to the first surface 14a and the first surface 14a via the stepped portion 15, and the first surface 14a is connected. A second surface 14b located on the low thermal expansion layer 11 side (Z2 side) than 14a is formed. That is, the cladding material 10 is formed so that the height positions in the Z direction of the first surface 14a and the second surface 14b are different. The height position of the first surface 14a and the height position of the second surface 14b can be appropriately adjusted based on the size of the connection target member in the Z direction and the like.

  Further, the surface 16 (the surface on the Cu layer 13 side of the clad material 10) 16 on the opposite side (Z2 side) of the clad material 10 is not formed with a step portion, and is a flat surface over substantially the entire surface. It is formed in a shape. As a result, the thickness of the clad material 10 on the first surface 14a side (X1 side) is larger than the thickness of the clad material 10 on the second surface 14b side (X2 side). The ratio (thickness ratio) of the thickness of the low thermal expansion layer 11, the Cu layer 12 and the Cu layer 13 to the thickness in the Z direction of the cladding material 10 on the first surface 14a side is the Z of the cladding material 10 on the second surface 14b side. It is substantially equal to the ratio (thickness ratio) of the thickness of the low thermal expansion layer 11, the Cu layer 12, and the Cu layer 13 to the thickness in the direction.

  The step portion 15 is formed so as to extend along the Y direction. And in the clad material 10, in the level | step-difference part 15, it is comprised so that the thickness of the clad material 10 may change continuously toward the X2 side from the X1 side. At this time, the low thermal expansion layer 11 and the Cu layers 12 and 13 of the clad material 10 are also configured to continuously change in thickness from the X1 side to the X2 side in the step portion 15. In addition, in the Cu layer 12 having a large amount of deformation in the Z direction in the step portion 15, it is preferable that the Cu layer 12 on the first surface 14a side and the Cu layer 12 on the second surface 14b side are continuously connected. That is, it is preferable that the Cu layer 12 is not cut off, and defects such as cracks and holes are not formed in the Cu layer 12. Thereby, it is possible to suppress that the electrical conductivity of the member 1 for electrical connection falls. In addition, if it is a part of Cu layer 12 (for example, less than 50% of Cu layer 12), a defect may be permitted.

  In order to suppress warping of the clad material 10, it is preferable that the Cu layer 12 and the Cu layer 13 have the same thickness ratio with respect to the low thermal expansion layer 11 in the Z direction. Further, in order to suppress warping of the clad material 10, the Cu layer 12 and the Cu layer 13 are preferably made of Cu or Cu alloy having the same composition with the same ductility.

  Here, as the thickness ratio of each layer of the cladding material 10 (thickness t1 of the low thermal expansion layer 11: thickness t2 of the Cu layer 12: thickness t3 of the Cu layer 13), for example, 1: 1: 1 and 1: 2: 1. 1: 3: 1, 1: 8: 1, and the like. The thickness ratio of each layer can be set in consideration of the balance between the thermal expansion amount and the volume resistivity in the clad material 10. The thickness t1 of the low thermal expansion layer 11 is preferably 25% or more with respect to the thickness t4 of the clad material 10. When the thickness t1 of the low thermal expansion layer 11 is 25% with respect to the thickness t4 of the cladding material 10, the thickness ratio is 1.5: 1: 1.5.

Here, the low thermal expansion layer 11 is made of 36 alloy, and the Cu layers 12 and 13 are pure Cu (average thermal expansion coefficient from room temperature to 300 ° C .: about 17 × 10 ⁻⁶ / K, volume resistivity: about 1. 7 × 10 ⁻⁸ Ω · m) is assumed. At this time, when the thickness ratio is 1: 1: 1, the average thermal expansion coefficient of the cladding material 10 from room temperature to 300 ° C. is about 11 × 10 ⁻⁶ / K, and the volume of the cladding material 10 is The resistivity is about 2.2 × 10 ⁻⁸ Ω · m. When the thickness ratio is 1: 3: 1, the average thermal expansion coefficient of the cladding material 10 from room temperature to 300 ° C. is about 7 × 10 ⁻⁶ / K, and the volume resistance of the cladding material 10 is The rate is about 4.1 × 10 ⁻⁸ Ω · m. When the thickness ratio is 1: 8: 1, the average thermal expansion coefficient of the cladding material 10 from room temperature to 300 ° C. is about 4 × 10 ⁻⁶ / K, and the volume resistance of the cladding material 10 is The rate is about 7.8 × 10 ⁻⁸ Ω · m.

Further, it is assumed that the low thermal expansion layer 11 is made of 42 alloy and the Cu layers 12 and 13 are made of pure Cu. At this time, when the thickness ratio is 1: 1: 1, the average thermal expansion coefficient of the cladding material 10 from room temperature to 300 ° C. is about 12 × 10 ⁻⁶ / K, and the volume of the cladding material 10 is The resistivity is about 2.5 × 10 ⁻⁸ Ω · m. When the thickness ratio is 1: 2: 1, the average thermal expansion coefficient of the cladding material 10 from room temperature to 300 ° C. is about 9 × 10 ⁻⁶ / K, and the volume resistance of the cladding material 10 is The rate is about 4.1 × 10 ⁻⁸ Ω · m. When the thickness ratio is 1: 8: 1, the average thermal expansion coefficient of the cladding material 10 from room temperature to 300 ° C. is about 6 × 10 ⁻⁶ / K, and the volume resistance of the cladding material 10 is The rate is about 7.7 × 10 ⁻⁸ Ω · m.

Further, it is assumed that the low thermal expansion layer 11 is made of 29Ni-17Co—Fe alloy and the Cu layers 12 and 13 are made of pure Cu. At this time, when the thickness ratio is 1: 1: 1, the average thermal expansion coefficient of the cladding material 10 from room temperature to 300 ° C. is about 10 × 10 ⁻⁶ / K, and the volume of the cladding material 10 is The resistivity is about 2.5 × 10 ⁻⁸ Ω · m. When the thickness ratio is 1: 2: 1, the average thermal expansion coefficient of the cladding material 10 from room temperature to 300 ° C. is about 6 × 10 ⁻⁶ / K, and the volume resistance of the cladding material 10 is The rate is about 4.1 × 10 ⁻⁸ Ω · m. When the thickness ratio is 1: 8: 1, the average thermal expansion coefficient of the cladding material 10 from room temperature to 300 ° C. is about 3 × 10 ⁻⁶ / K, and the volume resistance of the cladding material 10 is The rate is about 7.8 × 10 ⁻⁸ Ω · m.

[Configuration of electrical connection structure]
Next, an electrical connection structure 100a which is a part of the power module 100 using the electrical connection member 1 in the first embodiment will be described with reference to FIGS.

  For example, as shown in FIGS. 3 and 4, the electrical connection member 1 is used in an electrical connection structure 100 a that is a part of a power module 100 to which a lead frame 2 and a semiconductor element 3 such as a switching element are connected. It is done. The electrical connection member 1 is inverted from the state shown in FIGS. 1 and 2 so that the surface 14 on the Cu layer 12 side is located below (Z2 side) and the surface 16 on the Cu layer 13 side is located above (Z1 side). In this state, the lead frame 2 is disposed on the upper surface (the surface on the Z1 side) and the upper surface of the semiconductor element 3. The lead frame 2 and the semiconductor element 3 are examples of the “member to be connected” in the claims.

  The lead frame 2 is divided into a first portion 2a where the semiconductor element 3 is disposed on the upper surface and a second portion 2b where the semiconductor element 3 is not disposed. Here, the step portion 15 of the electrical connection member 1 is preferably formed to have a length in the Z direction substantially equal to the thickness (length in the Z direction) of the semiconductor element 3.

  In the electrical connection structure 100a, the electrical connection member 1 is connected to the lead frame 2 and the semiconductor element 3 via the connection material 4, so that the lead frame 2 and the semiconductor element 3 connect the electrical connection member 1 to each other. Is electrically connected. Specifically, the electrical connection member 1 and the lead frame 2 are connected via the connection material 4 at the electrical connection portion E1 of the first surface 14a of the electrical connection member 1. In addition, the electrical connection member 1 and the semiconductor element 3 are connected via the connection material 4 in the electrical connection portion E2 of the second surface 14b of the electrical connection member 1.

  Here, the difference in height position is absorbed by the difference in height position (step) in the Z direction between the upper surface of the lead frame 2 and the upper surface of the semiconductor element 3 by the step portion 15 of the electrical connection member 1. Can be substantially eliminated.

  The connecting material 4 is made of Ag (silver) obtained by reducing a connecting material paste 104 (see FIG. 9) containing silver oxide microparticles and a reducing agent (for example, triethylene glycol) by heat treatment. Here, since the connecting material 4 does not substantially melt up to the melting point of Ag (about 960 ° C.), even when the power module 100 reaches a high temperature of about 200 ° C. when the power module 100 is used, the electrical connecting member 1 and the lead frame 2 or the semiconductor element 3 can be reliably secured. As a result, the mechanical strength of the electrical connection structure 100a under a high temperature environment is improved.

  The connecting material 4 is formed in a layer shape having a thickness of, for example, nano-order. In FIG. 4, the thickness of the connecting material 4 (length in the Z direction) is exaggerated.

  The electrical connection structure 100a may be resin molded. Thereby, it is possible to maintain the electrical connection structure 100a stably.

[Method of manufacturing electrical connection member]
Next, with reference to FIG. 1, FIG. 2, and FIGS. 5-7, the manufacturing method of the member 1 for electrical connection in 1st Embodiment is demonstrated.

  First, as shown in FIG. 5, strip-like (plate-like) Cu materials 112 and 113 made of Cu or a Cu-based alloy, and an average from room temperature to 300 ° C. than the Cu or Cu alloy constituting the Cu material 112 A low thermal expansion steel material 111 made of an Fe alloy or Ni material having a small thermal expansion coefficient is prepared. In addition, the length of the width direction (Y direction) of the low thermal expansion steel material 111 and the Cu materials 112 and 113 is substantially equal. The Cu roller 112 is disposed (laminated) on one surface on the Z1 side of the low thermal expansion steel material 111 and the Cu roller 113 is disposed (laminated) on the other surface on the Z2 side of the low thermal expansion steel material 111. Continuously roll-join (rolling process). In addition, intermediate annealing can be performed as needed during the rolling process.

  As a result, a clad material 110 having a strip shape and a three-layer structure in which the Cu layer 12, the low thermal expansion layer 11, and the Cu layer 13 are laminated in this order is manufactured. At this time, since the Cu layer 12 and the Cu layer 13 having the same ductility are arranged so as to sandwich the low thermal expansion layer 11, the clad material 110 warps to the Cu layer 12 side or the Cu layer 13 side. It is possible to suppress.

  Then, continuous annealing is performed on the strip-shaped clad material 110 in the annealing furnace 202 to continuously perform diffusion annealing (diffusion annealing step). As a result, the band-shaped clad material 110a in which the low thermal expansion layer 11 and the Cu layer 12 are diffusion bonded at the atomic level and the low thermal expansion layer 11 and the Cu layer 13 are diffusion bonded at the atomic level is manufactured. The strip-shaped clad material 110a may be made so that the length in the width direction (Y direction, see FIG. 1) is equal to that of the electrical connection member 1, or the width in the width direction of the electrical connection member 1 You may produce so that it may become a width | variety magnitude | size, such as an integer multiple. For example, when the strip-shaped clad material 110a is manufactured to have a wide size such as an integer multiple, if the slit processing is performed on the manufactured clad material 110a with the length in the width direction of the electrical connecting member 1. Good.

  Then, the strip-shaped clad material 110a is cut to a predetermined length in the transport direction (X direction) (cutting step). Thereby, a plurality of individual clad materials 110b are produced.

  Here, in the manufacturing method of the first embodiment, as shown in FIG. 6, each of the plurality of individual clad members 110 b is plastically processed by, for example, pressing (pressing process). Specifically, the press machine 204 has an upper mold 205 and a lower mold 206. The lower surface (the surface on the Z2 side) of the upper mold 205 has a recess 205a that is recessed upward (in the Z1 direction). The recess 205a has a first inner bottom surface 205b corresponding to the first surface 14a (see FIG. 2) and a second inner surface located below the first inner bottom surface 205b and corresponding to the second surface 14b (see FIG. 2). An inner bottom surface 205c and a step portion 205d that connects the first inner bottom surface 205b and the second inner bottom surface 205c are formed. The size of the stepped portion 205d is appropriately set in consideration of the stepped portion between the connection target members (stepped portion between the lead frame 2 and the semiconductor element 3). The Cu layer 12 on the first surface 14a side and the Cu layer 13 on the second surface 14b side are not easily separated.

  Further, the upper surface (the surface on the Z1 side) of the lower mold 206 has a concave portion 206a that is recessed downward (in the Z2 direction). The recess 206a is configured to be slightly larger than the length of the clad material 110b in the X direction so that the clad material 110b can be fitted therein. Further, unlike the recess 205a of the upper mold 205, the inner bottom surface 206b of the recess 206a is formed in a flat surface shape.

  Further, in the state where the upper mold 205 is positioned at the lowest point (see FIG. 7), the separation distance L between the first inner bottom surface 205b of the recess 205a and the inner bottom surface 206b of the lower mold 206 in the upper mold 205 is approximately the clad material 110b. The press machine 204 is configured to be substantially equal to the thickness of the press.

  Then, the upper mold 205 is moved to the lowest point while the clad material 110b is disposed in the recess 206a of the lower mold 206 so that the surface 14 on the Cu layer 12 side is located above. Thereby, as shown in FIG. 7, the part facing the 2nd inner bottom face 205c and the level | step-difference part 205d of the clad material 110b is crushed. As a result, the surface 14 on the Cu layer 12 side (Z1 side) is connected to the first surface 14a via the first surface 14a and the stepped portion 15, and the lower thermal expansion layer 11 side (Z2 side) than the first surface 14a. The clad material 110c formed with the second surface 14b located at (1) is produced. Further, the surface 16 opposite to the Cu layer 12 (Z2 side) is formed into a flat surface by the inner bottom surface 206b of the recess 206a.

  In the pressing step, a part of the low thermal expansion layer 11, the Cu layer 12 and the Cu layer 13 flows in a gap between the upper mold 205 and the lower mold 206, and thereby, it is formed as a surplus (an example of an unnecessary part). There is a case. Therefore, for example, as shown in FIG. 8, a laser trimming device 207 is used to remove the surplus with laser light (trimming process). Thereby, the member 1 for electrical connection shown in FIG. 1 and FIG. 2 is produced.

[Method of manufacturing electrical connection structure]
Next, with reference to FIGS. 1-4 and FIG. 9, the manufacturing method of the electrical connection structure 100a of the power module 100 using the member 1 for electrical connection in 1st Embodiment is demonstrated.

  First, the electrical connection member 1 shown in FIGS. 1 and 2 and the lead frame 2 on which the semiconductor element 3 is arranged are prepared. Then, the electrical connection member 1 and the lead frame 2 are arranged on the mounting table 208 a in the heating furnace 208. At that time, from the state shown in FIG. 1 and FIG. 2, the surface 14 on the Cu layer 12 side is located below (Z2 side) and the surface 16 on the Cu layer 13 side is located above (Z1 side). In this inverted state, the lead frame 2 is disposed on the upper surface (the surface on the Z1 side) and the upper surface of the semiconductor element 3. At that time, the connecting material paste 104 is disposed between the electrical connection portion E1 of the first surface 14a and the upper surface of the lead frame 2, and between the electrical connection portion E2 of the second surface 14b and the upper surface of the semiconductor element 3. Then, the connecting material paste 104 is disposed. The connecting material paste 104 contains silver oxide microparticles and a reducing agent (for example, triethylene glycol).

  Then, the electrical connection member 1 is heat-treated by setting the temperature in the heating furnace 208 to 250 ° C. while pressing the flat surface 16 of the electrical connection member 1 from above with the pressing member 209. At this time, the inside of the heating furnace 208 is preferably a reducing atmosphere (for example, a hydrogen atmosphere) or a non-oxidizing atmosphere (for example, an inert gas atmosphere or a nitrogen atmosphere), but may be air. Thereby, silver oxide of the silver oxide microparticles is reduced by the reducing agent of the connecting material paste 104 to generate Ag. Then, the generated Ag layer having a thickness of, for example, nano-order connects the electrical connection portion E1 of the first surface 14a and the upper surface of the lead frame 2, and the electrical connection portion E2 of the second surface 14b and the semiconductor element 3 Connect the top surface. At this time, the flat surface 16 is pressed by the pressing member 209, whereby an equal pressure is applied to the Ag layers (connecting material 4) of the electrical connection portions E1 and E2. As a result, the electrical connection portion E1 of the first surface 14a and the upper surface of the lead frame 2 are connected with sufficient connection strength, and the electrical connection portion E2 of the second surface 14b and the upper surface of the semiconductor element 3 are sufficiently connected. Connected by strength. Thereby, the electrical connection structure 100a of the power module 100 shown in FIG. 3 and FIG. 4 is produced. Thereafter, resin molding may be performed on the electrical connection structure 100a portion of the power module 100.

  In the electrical connection structure 100a of the manufactured power module 100, even when the power module 100 reaches a high temperature of about 200 ° C. when the power module 100 is used, thermal expansion in the electrical connection member 1 is suppressed. As a result, in the electrical connection portions E1 and E2, it is possible to suppress the occurrence of damage such as cracks and peeling in the electrical connection member 1, the lead frame 2 or the semiconductor element 3, and the connection material 4.

(Effect of 1st Embodiment)
In the first embodiment, the following effects can be obtained.

  In the first embodiment, as described above, the electrical connection member 1 includes a Cu layer 12 made of Cu or a Cu alloy, and an Fe alloy having an average coefficient of thermal expansion from room temperature to 300 ° C. smaller than that of the Cu layer 12. Alternatively, a cladding material 10 is provided in which a low thermal expansion layer 11 made of a Ni material and a Cu layer 13 made of Cu or a Cu alloy are joined. Thereby, in the temperature range from room temperature to 300 ° C. which is a normal use environment of the electrical connecting member 1, the thermal expansion of the Cu layers 12 and 13 made of Cu or Cu alloy having a large thermal expansion is reduced. Can be suppressed. As a result, since the thermal expansion can be reduced in the entire clad material 10 including the Cu layers 12 and 13 and the low thermal expansion layer 11, the electrical connection portions E1 and E2 of the electrical connection member 1 are caused by thermal expansion. It is possible to suppress the stress to be applied. Therefore, it is possible to suppress the occurrence of damage such as cracks and peeling in the electrical connection portions E1 and E2 (connection material 4) due to thermal stress. Further, the first surface 14a and the first surface 14a are connected to the surface 14 on the Cu layer 12 side of the clad material 10 via the stepped portion 15, and the first surface 14a is located closer to the low thermal expansion layer 11 than the first surface 14a. 2 surfaces 14b. As a result, even if there is a difference in height position (step) between the lead frame 2 and the semiconductor element 3 to which the electrical connection member 1 is electrically connected, the surface of the clad material 10 on the Cu layer 12 side The step 15 formed in the step can absorb the step between the lead frame 2 and the semiconductor element 3. As a result, the effect of the step can be reduced, and the pressure can not be uniformly applied due to the step, so that the electrical connection member 1 and the lead frame 2 at the electrical connection portions E1 and E2 can be suppressed. (Semiconductor element 3) can be connected with sufficient connection strength. As a result, the electrical connection part E1 (E2), which is the part where the electrical connection member 1 and the lead frame 2 (semiconductor element 3) are connected via the connection material 4 due to thermal expansion, is damaged. Can be connected with sufficient connection strength at the electrical connection portion E1 (E2). Therefore, it is particularly effective to use the electrical connection member 1 of the first embodiment for the electrical connection structure 100a provided in the power module 100 that is likely to become high temperature when a high current flows. Further, when the clad material 10 is manufactured, the clad material 10 warps due to the large ductility of the Cu layer 12 made of Cu or Cu alloy. And the Cu layer 13 bonded to the opposite side (Z2 side) of the low thermal expansion layer 11 to the Cu layer 12 can be suppressed. Moreover, the volume resistivity of the electrical connection member 1 can be effectively reduced by providing the Cu layer 13 made of Cu or Cu alloy having a low volume resistivity.

  In the first embodiment, as described above, the surface 14 of the clad material 10 on the Cu layer 12 side is connected to the first surface 14a via the first surface 14a and the stepped portion 15, and the first surface 14a. 2nd surface 14b located in the low thermal expansion layer 11 side rather than. Thus, by connecting the lead frame 2 and the semiconductor element 3 to the Cu layer 12 side of the electrical connection member 1, electricity (current) can easily flow through the Cu layer 12 near the electrical connection portions E1 and E2. The power loss (power loss) during power transmission can be reduced because the Cu layer 12 through which current flows is made of Cu or Cu alloy having a low volume resistivity while being connected with connection strength.

  In the first embodiment, as described above, the surface 16 of the clad material 10 on the side opposite to the Cu layer 12 is formed with a flat surface without a stepped portion. Thereby, when connecting the lead frame 2 and the semiconductor element 3 to the Cu layer 12 side of the electrical connection member 1, it is possible to easily apply pressure evenly from the surface 16 on the side opposite to the flat Cu layer 12. it can. As a result, the electrical connection member 1 and the lead frame 2 (semiconductor element 3) can be connected with more sufficient connection strength at the electrical connection portion E1 (E2).

In the first embodiment, the low thermal expansion layer 11 is preferably made of an Fe alloy or Ni material having an average thermal expansion coefficient of 15 × 10 ⁻⁶ / K or less from room temperature (30 ° C.) to 300 ° C. Yes. If comprised in this way, the thermal expansion of Cu layer 12 (13) comprised from Cu or Cu alloy with large thermal expansion is 15 * 10 < ^-6 > / K or less in average thermal expansion coefficient from room temperature to 300 ^degreeC . The low thermal expansion layer 11 can be effectively suppressed. Thereby, it can suppress effectively that damage, such as a crack and peeling, arises in the electrical connection part E1 (E2).

  In the manufacturing method according to the first embodiment, as described above, plastic processing is performed on each piece of the clad material 110b by, for example, pressing. As a result, the surface 14 of the clad material 10 on the Cu layer 12 side is connected to the first surface 14a via the first surface 14a and the stepped portion 15, and is positioned closer to the low thermal expansion layer 11 than the first surface 14a. The second surface 14b can be easily formed.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. 10 and FIG. In the second embodiment, unlike the electrical connection member 1 of the first embodiment, a case where a part of the electrical connection member 301 is divided into a plurality of parts will be described. In addition, about the structure similar to the said 1st Embodiment, description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  In the electrical connection member 301 according to the second embodiment of the present invention, as shown in FIG. 10, the second surface 14 b side of the clad material 10 is divided into a plurality (three) along the Y direction in which the step portion 15 extends. Has been. Specifically, two notches 318a and 318b extending in the X direction from the vicinity of the stepped portion 15 to the end portion on the X2 side of the cladding material 10 are formed on the second surface 14b side of the cladding material 10. . The notches 318a and 318b are formed at a predetermined distance in the Y direction in which the step portion 15 extends. As a result, the second surface 14b side of the clad material 10 is divided into a plurality along the Y direction in which the step portion 15 extends. Therefore, it is possible to provide three electrical connection portions E2a, E2b, and E2c protruding in the X direction on the second surface 14b side of the clad material 10. As a result, one connection object member (see lead frame 2 and FIG. 3) disposed on the electrical connection portion E1 of the first surface 14a and the electrical connection portions E2a, E2b, and E2c of the second surface 14b, respectively. It is possible to electrically connect the three other members to be connected (semiconductor element 3, see FIG. 3) arranged by one electrical connection member 301. In addition, the other structure of 2nd Embodiment is the same as that of the said 1st Embodiment.

  Next, with reference to FIG. 10 and FIG. 11, the manufacturing method of the member 301 for electrical connection in 2nd Embodiment is demonstrated. In addition, since it is the same as the manufacturing method of the said 1st Embodiment until a press process, description is abbreviate | omitted.

  In the method of manufacturing the electrical connection member 301 in the second embodiment, the two notches 318a and 318b are formed by performing, for example, laser etching on the clad material 301a after the pressing process (etching process). . Specifically, the portions corresponding to the two notches 318 a and 318 b in the clad material 301 a are removed by etching using the laser etching apparatus 307. As a result, two notches 318a and 318b extending in the X direction from the vicinity of the stepped portion 15 to the X2 side end of the clad material 10 are formed on the second surface 14b side of the clad material 10. As a result, the second surface 14b side of the clad material 10 is divided into a plurality (three pieces) along the Y direction in which the step portion 15 extends. Thereafter, a trimming process is performed in the same manner as in the manufacturing method of the first embodiment, whereby the electrical connection member 301 shown in FIG. 10 is manufactured.

(Effect of 2nd Embodiment)
In the second embodiment, the following effects can be obtained.

  In the second embodiment, as described above, the electrical connection member 301 includes the Cu layer 12 composed of Cu or a Cu alloy, and the Fe alloy whose average thermal expansion coefficient from room temperature to 300 ° C. is smaller than that of the Cu layer 12. Alternatively, a cladding material 10 is provided in which a low thermal expansion layer 11 made of a Ni material and a Cu layer 13 made of Cu or a Cu alloy are joined. Thus, similarly to the first embodiment, the electrical connection portions E1 and E2a to E2c are connected with sufficient connection strength while suppressing the occurrence of damage to the electrical connection portions E1 and E2a to E2c due to thermal expansion. can do.

  In the second embodiment, as described above, the second surface 14 b side of the clad material 10 is divided into a plurality (three) along the Y direction in which the step portion 15 extends. As a result, a plurality of electrical connection portions E1 to E3 projecting in the X direction intersecting with the Y direction in which the stepped portion 15 extends are formed in the plurality of portions divided on the second surface 14b side of the clad material 10. One electrical connection member 301 electrically connects one connection target member arranged on the first surface 14a side and a plurality of other connection target members arranged on the second surface 14b side. can do. As a result, one of the one connection target member disposed on the first surface 14a side by one electrical connection member 301 and one of the plurality of other connection target members disposed on the second surface 14b side. The number of electrical connection members 301 required for connection can be effectively reduced as compared with the case where they are electrically connected. The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, a case will be described in which plating layers 417a and 417b are further provided on the electrical connection portions E1 and E2 of the electrical connection member 1 of the first embodiment, respectively. In addition, about the structure similar to the said 1st Embodiment, description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  In the electrical connection member 401 of the third embodiment of the present invention, as shown in FIG. 12, the electrical connection portion E1 of the first surface 14a of the clad material 10 and the electrical connection portion E2 of the second surface 14b are respectively Plating layers 417a and 417b are formed. The plating layers 417a and 417b are provided in order to improve the wettability of a connecting material (for example, the connecting material 4, see FIG. 4) made of a metal material.

  Specifically, the plating layers 417a and 417b are made of Ag, an Ag alloy, Ni, or a Ni alloy. In addition, as the plating layers 417a and 417b made of Ag, for example, an Ag plating layer by matte silver plating treatment may be used. Examples of the plating layers 417a and 417b made of an Ag alloy include an Ag alloy plating layer by bright silver plating and an Ag alloy plating layer containing Cu by electrolytic plating. Examples of the plating layers 417a and 417b made of Ni include Ni plating layers formed by electrolytic plating. Examples of the plating layers 417a and 417b made of Ni alloy include Ni-P alloy plating layers formed by electroless plating.

  The plating layers 417a and 417b have a minimum thickness that can improve the wettability of the connecting material, for example, a thickness of 5 μm or more that is not easily affected by the base (Cu layer 12). In order to suppress this, the thickness is preferably 10 μm or less. Thereby, the plating layers 417a and 417b can be formed in a short time, and the consumption of the material constituting the plating layers 417a and 417b can be reduced.

  In addition, the other structure of 3rd Embodiment is the same as that of the said 1st Embodiment. Moreover, the electrical connection member 401 of the third embodiment can be manufactured by performing a predetermined plating process on the electrical connection member 1 manufactured by the manufacturing method of the first embodiment. . In the plating process, it is necessary to form a mask in a portion where the plating layers 417a and 417b are not formed.

(Effect of the third embodiment)
In the third embodiment, the following effects can be obtained.

  In the third embodiment, as described above, the electrical connection member 401 includes the Cu layer 12 made of Cu or Cu alloy, and the Fe alloy having an average coefficient of thermal expansion from room temperature to 300 ° C. smaller than that of the Cu layer 12. Alternatively, a cladding material 10 is provided in which a low thermal expansion layer 11 made of a Ni material and a Cu layer 13 made of Cu or a Cu alloy are joined. Thereby, similarly to 1st Embodiment, it can connect with sufficient connection intensity | strength in electrical connection part E1 and E2, suppressing generation | occurrence | production of damage to electrical connection part E1 and E2 resulting from thermal expansion. .

  In the third embodiment, as described above, the electrical connection portion E1 of the first surface 14a of the clad material 10 and the electrical connection portion E2 of the second surface 14b are respectively Ag, Ag alloy, Ni, or Ni alloy. Plating layers 417a and 417b composed of Thereby, when using the connection material which consists of metal materials, such as a brazing material, for the connection of the electrical connection member 401 and the connection object member, the wettability of the connection material can be improved by the plating layers 417a and 417b. As a result, the electrical connection member 401 and the connection target member can be reliably connected by the connection material. The remaining effects of the third embodiment are similar to those of the aforementioned first embodiment.

(Modification of the third embodiment)
Next, a modification of the third embodiment of the present invention will be described with reference to FIG. In this modification of the third embodiment, a case will be described in which a plating layer 517 is provided over the entire surface of the clad material 10, unlike the electrical connection member 401 of the third embodiment. In addition, about the structure similar to the said 3rd Embodiment, description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  In the electrical connection member 501 of the modification of the third embodiment of the present invention, as shown in FIG. 13, the plating layer 517 made of Ag, Ag alloy, Ni or Ni alloy is formed on the entire surface of the clad material 10. Is formed. That is, the plating layer 517 is formed not only on the surface 14 of the clad material 10 on the Cu layer 12 side but also on the surface 16 opposite to the Cu layer 12 and the side surface of the clad material 10. As a result, the entire first surface 14a can be suitably used as an electrical connection portion, and the entire second surface 14b can be suitably used as an electrical connection portion.

  In addition, the other structure of the modification of 3rd Embodiment is the same as that of the said 3rd Embodiment. The electrical connection member 501 of the modification of the third embodiment is the same as the manufacturing method of the third embodiment except that the plating layer 517 is formed without forming a mask.

(Effects of Modification of Third Embodiment)
In the modification of the third embodiment, the following effects can be obtained.

  In the modification of the third embodiment, the plating layer 517 is formed on the entire surface of the clad material 10 as described above. Thus, unlike the case where the plating layer is formed only on a part of the surface of the clad material 10, it is not necessary to form a mask, and therefore the plating layer 517 can be easily formed. Further, since the electrical connection portions E1 and E2 can be secured in a wide range on the first surface 14a and the second surface 14b, respectively, the electrical connection member 501 and the connection target member can be reliably and easily connected by the connection material. Can do. Furthermore, the corrosion resistance of the clad material 10 can be improved by the plating layer 517 using Ag, Ag alloy, Ni or Ni alloy, which is superior in corrosion resistance compared to an Fe alloy containing no Cu and Cr. The remaining effects of the modification example of the third embodiment are similar to those of the aforementioned third embodiment.

(Modification)
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first to third embodiments, the clad material 10 has an example of a three-layer structure in which the Cu layer 12, the low thermal expansion layer 11, and the Cu layer 13 are joined in this order. The present invention is not limited to this. In the present invention, the clad material may be a clad material having a two-layer structure or a four-layer structure or more. For example, as in the modification of the first embodiment shown in FIG. 14, the clad material 610 includes a Cu layer 12 composed of Cu or a Cu alloy, and an average thermal expansion coefficient from room temperature to 300 ° C. is higher than that of the first Cu layer. Alternatively, a clad material 610 having a two-layer structure joined to a low thermal expansion layer 611 made of a small Fe alloy or Ni material may be used. In this case, the step portion 15 is formed on the Cu layer 12 side (Z1 side) of the low thermal expansion layer 611 to provide the first surface 14a and the second surface 14b including the electrical connection portions E1 and E2 (see FIG. 1), respectively. . Note that the surface 616 of the low thermal expansion layer 611 opposite to the Cu layer 12 (Z2 side) is preferably flat. As a result, unlike the first to third embodiments, the second Cu layer that easily undergoes thermal expansion is not provided, so that it is possible to more reliably suppress damage to the electrical connection portion due to thermal expansion. it is conceivable that.

  In the first embodiment, the first surface 14a, the second surface 14b, and the second surface 14b are obtained by cutting the strip-shaped clad material 110a so as to have a predetermined length in the transport direction, and then performing plastic working using a press, for example. Although the example which produced the clad | crud material 10 in which the level | step-difference part 15 was formed was shown, this invention is not limited to this. In the present invention, for example, after forming a strip-shaped clad material having a first surface, a second surface, and a stepped portion by plastic working by pressing, the strip-shaped clad material has a predetermined length in the transport direction. It may be cut into pieces. Thereby, it is possible to produce the electrical connection member continuously. In this case, the trimming process is preferably performed after the pressing process and before the cutting process. Similarly, in the second embodiment, for example, a belt-shaped clad material in which the first surface, the second surface, and the stepped portion are formed by plastic working by pressing, for example, and then the belt-shaped clad material is transported in the transport direction. You may cut | disconnect so that it may become predetermined length. In this case, the etching process in which the notch is formed is performed after the pressing process and before the cutting process (before the etching process).

  In the first embodiment, each of the individual clad members 110b is subjected to plastic working by pressing, for example, so that the surface 14 on the Cu layer 12 side of the clad material 10 has a first surface 14a and An example is shown in which the first surface 14a is connected to the first surface 14a through the step portion 15 and the second surface 14b located on the low thermal expansion layer 11 side with respect to the first surface 14a is formed. However, the present invention is limited to this. Absent. In the present invention, the first surface, the second surface, and the stepped portion may be formed by plastic working by a method other than pressing. For example, the first surface, the second surface, and the stepped portion are formed by performing plastic working by so-called roll reduction to reduce the thickness by applying pressure using a rolling roll only to a portion corresponding to the second surface of the clad material. May be formed.

  Moreover, although the example which removes the surplus with a laser beam using the laser trimming apparatus 207 was shown in the said 1st Embodiment, this invention is not limited to this. In the present invention, the excess wall may be removed by a method other than laser light. For example, the surplus may be removed by pressing using a press trimming device, or a portion other than between the cutters is removed by passing between a plurality of cutters arranged at a predetermined distance. The surplus may be removed by this (so-called slit processing). Moreover, it is not necessary to remove the surplus depending on the situation and application of the clad material after the pressing process.

  Further, in the second embodiment, the example in which the two notches 318a and 318b are formed by performing the laser etching process on the clad material 301a after the pressing process has been described. Not limited. In the present invention, the notch may be formed by a processing method other than the laser etching process. For example, the notch may be formed by punching a portion corresponding to the notch of the clad material with a press.

  In the second embodiment, the example in which the second surface 14b side of the clad material 10 is divided into three along the Y direction in which the step portion 15 extends is shown. However, the present invention is not limited to this. In the present invention, the second surface side of the clad material may be divided into two or four or more.

  Moreover, although the example which performs a trimming process after performing a laser etching process was shown in the said 2nd Embodiment, this invention is not limited to this. In the present invention, the laser etching process may be performed after the trimming process.

  Moreover, in the said 1st Embodiment, using the connection material 4 comprised from Ag (silver) by which the connection material paste 104 containing a silver oxide microparticle and a reducing agent was reduced by heat processing, Although the example which connects a connection object member (the lead frame 2 and the semiconductor element 3) was shown, this invention is not limited to this. In the present invention, the material of the connecting material is not particularly limited as long as it has conductivity. For example, a metal material such as solder or a conductive adhesive may be used as the connecting material. Further, the electrical connection member and the connection target member may be connected by laser welding or ultrasonic welding. In this case, by forming the plating layer of the third embodiment in the electrical connection portion of the electrical connection member, the plating layer and its vicinity are melted by welding heat to become a connection material. It is possible to easily connect the connection target member.

  In the first to third embodiments, the surface 16 opposite to the Cu layer 12 (first Cu layer) of the clad material 10 is shown as a flat surface. However, the present invention is not limited to this. I can't. In the present invention, the surface of the cladding material opposite to the first Cu layer may not be formed into a flat surface.

1, 301, 401, 501, 601 Electrical connection member 2 Lead frame (member to be connected)
3 Semiconductor elements (members to be connected)
10, 110, 610 Clad material 11, 611 Low thermal expansion layer 12 Cu layer (first Cu layer)
13 Cu layer (second Cu layer)
14 Surface (surface on the 1st Cu layer side)
14a First surface 14b Second surface 15 Stepped portion 16, 616 Surface (surface opposite to the first Cu layer)
100a Electrical connection structure 417a, 417b, 517 Plating layer

Claims (11)

A first Cu layer composed of Cu or a Cu alloy;
A low thermal expansion layer composed of an Fe alloy or Ni material having an average thermal expansion coefficient from room temperature to 300 ° C. smaller than that of the first Cu layer, and the low thermal expansion layer on the opposite side of the first Cu layer; Or a clad material in which a second Cu layer composed of a Cu alloy is joined in this order ,
A surface on the first Cu layer side of the clad material is connected to the first surface via a stepped portion, and a second surface located on the low thermal expansion layer side with respect to the first surface, Is formed,
The first surface and the second surface have electrical connection portions;
The thickness of the clad material of the first surface, the second much larger than the thickness of the surface side of the cladding material, the low thermal expansion layer to the thickness of the clad material of the first surface, the first 1Cu layer And the ratio of the thickness of the second Cu layer is substantially equal to the ratio of the thickness of the low thermal expansion layer, the first Cu layer, and the second Cu layer to the thickness of the cladding material on the second surface side .   2. The electrical connection member according to claim 1, wherein a surface of the clad material opposite to the first Cu layer is formed in a flat surface shape having no stepped portion. The member for electrical connection according to claim 1 or 2 , wherein the second surface side of the clad material is divided into a plurality along the direction in which the stepped portion extends. The low thermal expansion layer is composed of a Fe alloy or Ni material having an average thermal expansion coefficient of less 15 × 10 -6 ^{/ K} to 300 ° C. from room temperature, according to any one of claims 1 to 3 Electrical connection member. At least one is of the electrical connections of the electrical connecting portion or the second surface before Symbol first surface, Ag, Ag alloy, plated layer formed of Ni or Ni alloy is formed, according to claim 1 The member for electrical connection according to any one of to 4 . The member for electrical connection according to claim 5 , wherein the plating layer is formed on the entire surface of the clad material. A first Cu layer composed of Cu or Cu alloy, a low thermal expansion layer composed of Fe alloy or Ni material having an average coefficient of thermal expansion from room temperature to 300 ° C. smaller than that of the first Cu layer, and the low thermal expansion layer The clad material is disposed on the opposite side of the first Cu layer and joined with a second Cu layer made of Cu or a Cu alloy in this order, and the surface of the clad material on the first Cu layer side includes A first surface and a second surface that is connected to the first surface via a stepped portion and is located on the low thermal expansion layer side with respect to the first surface; and the first surface and the second surface has an electrical connection portion, to said thickness of said clad material of the first surface, the second much larger than the thickness of the clad material on the surface side, the thickness of the clad material of the first surface The low thermal expansion layer, the first Cu layer and the thickness ratio of the first 2Cu layer, wherein the low thermal expansion layer to the thickness of the clad material of the second surface, the first 1Cu layer and substantially equal to the electrical connection member and the ratio of the thickness of the first 2Cu layer When,
An electrical connection structure comprising: a connection material that connects the electrical connection member and a connection target member at electrical connection portions of the first surface and the second surface. At least a first Cu layer composed of Cu or Cu alloy by rolling joining and a low thermal expansion layer composed of Fe alloy or Ni material having an average coefficient of thermal expansion from room temperature to 300 ° C. smaller than that of the first Cu layer. Make a bonded clad material,
After the production of the clad material by the rolling bonding, by performing plastic working on the produced clad material, on the surface of the clad material on the first Cu layer side, the first surface and the step portion A method for manufacturing an electrical connection member, wherein the second surface is connected to a first surface and is located closer to the low thermal expansion layer than the first surface. The electrical connection member according to claim 8 , wherein after forming the first surface and the second surface, an unnecessary portion that flows when the first surface and the second surface are formed is cut and removed. Production method. After forming said first surface and said second surface, said second surface of the clad material into a plurality in the direction of extension of the step portion, for electric connection according to claim 8 or 9 Manufacturing method of member. The clad in which the first Cu layer, the low thermal expansion layer, and the second Cu layer made of Cu or a Cu alloy are bonded to the opposite side of the low thermal expansion layer to the first Cu layer by the rolling bonding. making wood, manufacturing method of the electrical connection member according to any one of claims 8-10.

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