Development of molded fine-pitch ball grid array (FPBGA) using through-hole bonding process

Abstract

A molded fine-pitch ball grid array (FPBGA) structure, consisting of the fabricated chip, carrier tape, molded resin, and solder bumps, has many advantages over conventional structures for chip-scale packages. The assembly process of FPBGA consists of through-hole bonding, lamination, molding, solder bump formation, and outline cutting. The bonding process, which is called through-hole bonding, does not have lead bending or wire or lead crossing and allows a finer chip pad pitch to be used. However, since it is difficult to evaluate the bonding strength of each part, unlike wire bonding or TAB inner lead bonding, we developed several methods for evaluating the through-hole bonding. In the fabrication of molded FPBGA, the back side of the chip is molded by resin, which improves the robustness of the package. In this process, it is important to keep coplanarity of the package surface. We are currently testing the reliability of the molded FPBGA and results are good.