Fabrication method of semiconductor package having electrical connecting structures

A fabrication method of a semiconductor package having electrical connecting structures, comprising the steps of:

• providing a metal board with a plurality of substrate units;
• forming a patterned metal layer on the substrate units;
• forming a conductive layer on the metal layer, wherein the conductive layer has a die pad and a plurality of traces disposed at a periphery of the die pad, the traces each comprising a trace body, a finger pad formed at an end of the trace body and positioned proximate to the die pad, and a trace end formed at another end of the trace body and positioned distal to the die pad;
• mounting a chip on the die pad and electrically connecting the chip to the finger pads through bonding wires;
• forming an encapsulant to cover the chip, the bonding wires and the conductive layer;
• removing the metal board and the metal layer so as to expose the conductive layer;
• forming a solder mask layer on bottom surfaces of the conductive layer and the encapsulant to cover the conductive layer and the encapsulant, followed by forming a plurality of openings in the solder mask layer to expose the trace ends, respectively;
• forming a plurality of solder balls in the openings of the solder mask layer, respectively, so as to electrically connect the solder pads to the trace ends;
• and
• singulating the substrate units from each other so as to obtain a plurality of semiconductor packages.