Patent ID: 7459345

Claim:
A packaging method for an electronic element, comprising the steps of: etching portions of a top surface of a metal board made of copper to form several recesses between raised unetched segments and filling the recesses with a dielectric material of high metal density polymer while keeping the raised unetched segments exposed; forming multiple solder balls in contact with the raised unetched segments by plating; coating the solder balls with a thin metal paste layer; bonding contacts on a die respectively to the solder balls with the thin metal paste layer; injecting an underfill between the die and the metal board; sealing the die with an outer encapsulant; etching a bottom surface of the metal board to form multiple metal leads; coating the metal leads with a metal layer; attaching an isolator between the metal leads; coating the bottom surface of the metal board other than the metal leads with a solder resist; and conducting a continuity test.