Semiconductor device and vehicle

A semiconductor device comprising:

• a semiconductor element, including:
• a semiconductor layer,
• a plurality of metal layers stacked on the semiconductor layer, and
• an insulating layer formed between the plurality of metal layers in a top view of the semiconductor element and extending in an extending direction,
• a top surface of the plurality of metal layers and the insulating layer being a first surface of the semiconductor element;
• and
• a metal wiring board having a bonded portion bonded to the plurality of metal layers of the semiconductor element via a bonding material, wherein
• the bonded portion of the metal wiring board has:
• a first main surface facing the first surface of the semiconductor element, and
• a second main surface opposite to the first main surface,
• the bonded portion further has, on the first main surface:
• a bonded surface facing the plurality of metal layers;
• a recess formed in the bonded surface to separate the bonded surface into a plurality of bonded surface portions, and
• a protrusion located immediately adjacent to the recess and protruding from the bonded surface to the first surface of the semiconductor element,
• the recess extends in the extending direction at a position facing the insulating layer on the first surface of the semiconductor element,
• the protrusion extends along the recess, and
• an air passage is formed within the recess and is continuous from one end to another end in the extending direction in the recess.