Ball grid assembly type semiconductor device having a heat diffusion function and an electric and magnetic shielding function

A ball grid assembly type semiconductor device comprising:

• a) a circuit substrate having a first lead pattern and a second lead pattern on a front surface and a rear surface of said circuit substrate respectively, said first lead pattern having a die mounted region at a central portion of said front surface of said circuit substrate and a plurality of conductive leads arranged around said die mounting region on said front surface of said circuit substrate, said second lead pattern including a plurality of first outer connecting terminal lands connected with said die mounted region by a plurality of first vias, a plurality of second outer connected terminal lands connected with said conductive leads of said first lead pattern to a plurality of second vias, a ground plane substantially entirely covering said rear surface and electrically connected with said first outer connected terminal lands and electrically and magnetically shielded from said second outer connecting terminal lands by a plurality of annular gaps around said second outer connecting terminal lands,
• b) a first dielectric layer coated on said first lead pattern and a second dielectric layer coated on said second lead pattern, but not on said first and second outer connecting terminal lands, said first and second dielectric layers being silk screen printed solder resistant film layers,
• c) a plurality of solder balls mounted on said first and second outer connecting terminal lands respectively,
• d) a semiconductor die fixedly mounted on said die mounting region by an electrically conductive adhering agent,
• e) a plurality of bonding wires connecting a plurality of electrode pads mounted on said semiconductor die with a plurality of said conductive leads respectively, and
• f) a resin package sealing said front surface of said circuit substrate on which said semiconductor die and said bonding wires are mounted.