Power storage pack, semiconductor device, and semiconductor device manufacturing method

A semiconductor device comprising:

• a semiconductor element of chip-size package type including a plurality of external connection terminals;
• and
• a first metal plate including a portion whose thickness is at most 0.2 mm, wherein
• the semiconductor element includes one main surface to which the first metal plate is connected,
• the semiconductor element includes an other main surface that includes a substrate connection terminal to be connected to a mounting substrate on which the semiconductor element is mounted, the other main surface and the one main surface facing in opposite directions, the substrate connection terminal being included in the plurality of external connection terminals,
• the first metal plate includes a first main surface connected to the semiconductor element and a second main surface on which a joint preparation region for joining the first metal plate and a second metal plate is provided, the second main surface and the first main surface facing in opposite directions,
• in a plan view of the first metal plate, the joint preparation region does not overlap a connection region in which the first metal plate is connected to the semiconductor element,
• the first metal plate has a same electric potential as at least one of the plurality of external connection terminals,
• the first metal plate is bendable at the portion whose thickness is at most 0.2 mm to include a portion in which second main surfaces face each other,
• the semiconductor device further comprises a third metal plate between the semiconductor element and the first metal plate,
• the third metal plate is connected to the semiconductor element on the one main surface of the semiconductor element and is connected to the first metal plate on the first main surface of the first metal plate, and
• the first metal plate is connected to the one main surface of the semiconductor element via the third metal plate.