Wiring substrate and semiconductor device

摘要

A wiring substrate has a semiconductor device mounted thereonto, the semiconductor device having ball-shaped externally connecting parts. The wiring substrate includes through holes at positions corresponding to the ball-shaped externally connecting parts and electric conductors provided inside and around the through holes. Land portions of the electric conductors, at which the electric conductors are engaged with the externally connecting parts, includes sectional tapering portions, respectively. Further, the through holes have sectional tapering portions at edge portions in proximity to the land portions, respectively. The ball-shaped externally connecting parts of the semiconductor device are engaged with the land portions provided around the through holes of the wiring substrate and having the sectional tapering portions, respectively.