Bonding pads are formed on a main surface of a semiconductor chip. An insulating layer having openings located on the bonding pads is formed on the main surface of the semiconductor chip. Base metal layers are formed on the bonding pads. A buffer coat film having a portion laid on a periphery of the base metal layer is formed on the insulating layer. Connection layers are formed on the base metal layers. First conductors are formed on the connection layers. A seal resin exposing only top surfaces of the first conductors is formed. Lumpish second conductors are formed on the top surfaces of the first conductor. Thereby, a resin seal semiconductor package can be made compact and it has improved electrical characteristics and high reliability.