Method of manufacturing semiconductor device, flexible substrate, and semiconductor device

A semiconductor chip is mounted on a flexible substrate wherein internal connecting electrodes to be connected to protruding electrodes on an element surface of the semiconductor chip and wires for connecting the internal connecting electrodes and the external connecting electrodes to be connected to external devices are provided on a surface of an insulating film . The internal connecting electrodes , the wires and the surface of the insulating film are coated with a protective film . The protruding electrodes and the internal connecting electrodes are connected by arranging the element surface of the semiconductor chip to face the flexible substrate and causing the protruding electrodes on the element surface to pierce the protective film . This semiconductor device manufacturing method makes it possible to prevent ion migration and reduce occurrence of short circuit between wires.