To ensure a sufficient underfill sealing strength by canceling a creep-up lack of an underfill to a side face of each corner of semiconductor electronic parts in a semiconductor device formed by carrying out sealing of an underfill to the semiconductor electronic parts in the shape of almost rectangular plane.

This invention relates to a semiconductor device 1a formed by carrying out sealing of the underfill 5 to semiconductor electronic parts 10 in the shape of almost rectangular plane on a substrate 2 with a solder resist film layer 3. In the solder resist film layer 3, there is formed a groove 30 around a packaging region of the semiconductor electronic parts, while making a contour in the shape of almost rectangular plane mostly along a contour shape of the semiconductor electronic parts. While an electrode pat 40 is formed inside almost rectangular corner in the shape of the groove over the substrate 2, a solder resist on the electrode pat is opened, and a solder projection 50 is formed on the electrode pat.