Mounted structure

1. A mounted structure comprising:

an electrode of a substrate;

an electrode of a semiconductor element; and

a mounted layers that bonds the electrode of the substrate and the electrode of the semiconductor element,

wherein the mounted layers includes along a direction from the substrate toward the semiconductor element:

a first intermetallic compound layer containing a CuSn-based intermetallic compound;

a Bi layer;

a second intermetallic compound layer containing a CuSn-based intermetallic compound;

a Cu layer; and

a third intermetallic compound layer containing a CuSn-based intermetallic compound.

2. The mounted structure according to claim 1 , wherein the mounted layers further includes:

a Bi layer; and

a fourth intermetallic compound layer containing a CuSn-based intermetallic compound, and

the above layers are sequentially arranged between the third intermetallic compound layer and the electrode of the semiconductor element.

3. The mounted structure according to claim 1 , wherein the CuSn-based intermetallic compound includes at least one intermetallic compound of Cu 6 Sn 5 and Cu 3 Sn.

4. The mounted structure according to claim 1 , wherein the Cu layer has a thickness of 6.2 μm or more.

5. The mounted structure according to claim 4 , wherein a mount plane between the mounted layers and the electrode of the semiconductor element has an area of between 5 mm 2 and 100 mm 2 .

6. The mounted structure according to claim 1 , wherein the first intermetallic compound layer contains the CuSn-based intermetallic compound, and includes an AgSn-based intermetallic compound.

7. The mounted structure according to claim 2 , wherein the fourth intermetallic compound layer contains the CuSn-based intermetallic compound, and includes an AgSn-based intermetallic compound.