Package warpage evaluation for high performance PQFP

An electrically and thermally enhanced QFP (ETE-QFP) has been developed to provide a cost effective packaging solution for high pin-count, high performance applications. The ETE-QFP incorporates a multi-layer printed circuit board into the leadframe for electrical enhancement and a heat slug for increased thermal dissipation. The heat slug on one side of the ETE-QFP package creates an unbalanced mold compound distribution, making the package susceptible to warpage. This paper describes a package warpage evaluation on ETE-QFP after the molding process. Several mold compounds were evaluated to determine their effect on package warpage. Experimentation and finite element analysis were used to study the effect of mold compounds on package bending. The effect of package warpage on lead coplanarity is also discussed. It is concluded that mold compound selection is critical for controlling package warpage and lead coplanarity