Electrical connection member, electrical connection structure, and method for manufacturing electrical connection member

1. An electrical connection member ( 1 , 301 , 401 , 501 , 601 ) comprising: a clad material ( 10 , 110 , 610 ) including at least both a first Cu layer ( 12 ) made of a Cu material and a low thermal expansion layer ( 11 ) made of an Fe material or Ni material having an average thermal expansion coefficient from room temperature to 300° C. smaller than that of the first Cu layer, the first Cu layer and the low thermal expansion layer being bonded to each other; wherein a surface of the clad material on a side of the first Cu layer includes a first surface ( 14 a ) connected to a first connection target member and a second surface ( 14 b ) directly connected to the first surface via a step ( 15 ), which inclines with regard to a stacking direction, and located closer to the low thermal expansion layer than the first surface and connected to a second connection target member, a first thickness of the clad material of the first surface is greater than a second thickness of the clad material of the second surface, and wherein a thickness of the clad material gradually decreases from the first thickness of the first surface to the second thickness of the second surface in the step.

2. The electrical connection member according to claim 1 , wherein a surface of the clad material opposite to the first Cu layer is flat without a step.

3. The electrical connection member according to claim 1 , wherein the clad material further includes a second Cu layer ( 13 ) bonded to a side of the low thermal expansion layer opposite to the first Cu layer and made of a Cu material.

4. The electrical connection member according to claim 1 , wherein a portion of the clad material on a side of the second surface is divided into a plurality of portions along a direction in which the step extends.

5. The electrical connection member according to claim 1 , wherein the low thermal expansion layer is made of an Fe material or Ni material having an average thermal expansion coefficient of 15×10 −6 /K or less from room temperature to 300° C.

6. The electrical connection member according to claim 1 , wherein

each of the first surface and the second surface includes an electrical connection portion; and

at least one of the electrical connection portion of the first surface or the electrical connection portion of the second surface includes a plated layer made of Ag, a Ag alloy, Ni, or a Ni alloy.

7. The electrical connection member according to claim 6 , wherein the plated layer is formed on an entire surface of the clad material.

8. An electrical connection structure ( 100 a ) comprising: an electrical connection member ( 1 , 301 , 401 , 501 , 601 ) including a clad material ( 10 , 110 , 610 ) that includes at least both a first Cu layer ( 12 ) made of a Cu material and a low thermal expansion layer ( 11 ) made of an Fe material or Ni material having an average thermal expansion coefficient from room temperature to 300° C. smaller than that of the first Cu layer, the first Cu layer and the low thermal expansion layer being bonded to each other, the clad material having a surface on a side of the first Cu layer, the surface including a first surface ( 14 a ) connected to a first connection target member and a second surface ( 14 b ) directly connected to the first surface via a step ( 15 ), which inclines with regard to a stacking direction, and located closer to the low thermal expansion layer than the first surface and connected to a second connection target member, a first thickness of the clad material of the first surface is greater than a second thickness of the clad material of the second surface, and wherein a thickness of the clad material gradually decreases from the first thickness of the first surface to the second thickness of the second surface in the step; and a connection material to connect the electrical connection member to the first connection target member in an electrical connection portion of the first surface and to connect the electrical connection member to the second connection target member in an electrical connection portion of the second surface.

9. The electrical connection member according to claim 1 , wherein the step has a length in a stacking direction equal to a difference between a thickness of the first connection target member connected to the first surface and a thickness of the second connection target member connected to the second surface.

10. The electrical connection structure according to claim 8 , wherein the step has a length in a stacking direction equal to a difference between a thickness of the first connection target member connected to the first surface and a thickness of the second connection target member connected to the second surface.