A semiconductor device comprising: a connecting base including: a semiconductor substrate, a surface insulating-film having a flat upper face and provided on the semiconductor substrate, a multi-level interconnection (22, 23) buried in the surface insulating-film, and a surface electrode arranged on the upper face of the surface insulating-film and connected to the multi-level interconnection (22, 23); and an external connection mechanism including: a passivation film covering the upper face of the surface insulating-film and the surface electrode, establishing a groove that exposes a central part of the surface electrode at a bottom, the passivation film comprising a mesa-shaped portion located above the surface electrode; a barrier-metal film spanning from an upper face of the surface electrode exposed at the bottom of the groove up to an upper face of the passivation film corresponding to an area of the mesa-shaped portion so as to cover an area corresponding to the surface electrode in a plane pattern; and a plurality of micro-bumps arranged on a limited portion of the barrier-metal film located on the passivation film, the limited portion corresponding to the area of the mesa-shaped portion. a connecting base including: a semiconductor substrate, a surface insulating-film having a flat upper face and provided on the semiconductor substrate, a multi-level interconnection (22, 23) buried in the surface insulating-film, and a surface electrode arranged on the upper face of the surface insulating-film and connected to the multi-level interconnection (22, 23); and a semiconductor substrate, a surface insulating-film having a flat upper face and provided on the semiconductor substrate, a multi-level interconnection (22, 23) buried in the surface insulating-film, and a surface electrode arranged on the upper face of the surface insulating-film and connected to the multi-level interconnection (22, 23); and an external connection mechanism including: a passivation film covering the upper face of the surface insulating-film and the surface electrode, establishing a groove that exposes a central part of the surface electrode at a bottom, the passivation film comprising a mesa-shaped portion located above the surface electrode; a barrier-metal film spanning from an upper face of the surface electrode exposed at the bottom of the groove up to an upper face of the passivation film corresponding to an area of the mesa-shaped portion so as to cover an area corresponding to the surface electrode in a plane pattern; and a plurality of micro-bumps arranged on a limited portion of the barrier-metal film located on the passivation film, the limited portion corresponding to the area of the mesa-shaped portion. a passivation film covering the upper face of the surface insulating-film and the surface electrode, establishing a groove that exposes a central part of the surface electrode at a bottom, the passivation film comprising a mesa-shaped portion located above the surface electrode; a barrier-metal film spanning from an upper face of the surface electrode exposed at the bottom of the groove up to an upper face of the passivation film corresponding to an area of the mesa-shaped portion so as to cover an area corresponding to the surface electrode in a plane pattern; and a plurality of micro-bumps arranged on a limited portion of the barrier-metal film located on the passivation film, the limited portion corresponding to the area of the mesa-shaped portion.