The present invention include a semiconductor device and a method therefor, the method includes disposing a sheet-shaped resin at a side opposite to the chip mounting portion mounting semiconductor chips to be mounted on the chip mounting portion, and forming a resin sealing portion between the sheet-shaped resin and the chip mounting portion, to seal the semiconductor chips. According to an aspect of the present invention, it is possible to provide a semiconductor device and a fabrication method therefor, by which it is possible to reduce the size of the package and to prevent the generation of an unfilled portion in a resin sealing portion or a filler-removed portion or to prevent the exposure of wire from the resin sealing portion.