FIRST-PLATING-THEN-ETCHING QUAD FLAT NO-LEAD (QFN) PACKAGING STRUCTURES AND METHOD FOR MANUFACTURING THE SAME

摘要

A method is disclosed for manufacturing a first-plating-then-etching quad flat no-lead (QFN) packaging structure. The method includes providing a metal substrate, forming a first photoresist film on a top surface of the metal substrate, and forming a plating pattern in the first photoresist film using photolithography. The method also includes forming a first metal layer containing a plurality of inner leads by a first multi-layer electrical plating process using the plating pattern in the first photoresist film as a mask such that a lead pitch of the plurality of inner leads is significantly reduced. Further, the method includes attaching at least one die in a predetermined region on the top surface of the metal substrate, connecting the die and the plurality of inner leads using metal wires by a wire bonding process, and sealing the die, the plurality of inner leads, and metal wires with a molding compound. The method also includes forming a second metal layer on a back surface of the metal substrate by a second multi-layer electrical plating process and, after forming the second metal layer, etching the metal substrate from the back surface of the metal substrate to form a plurality of I/O pads with pre-formed second metal layer corresponding to the plurality of inner leads. Further, the method includes filling sealant in etched areas at the back surface of the metal substrate.