NCF for wafer lamination process in higher density electronic packages

Abstract

We have developed a novel NCF (Non Conductive Film) which can be applied to the wafer lamination process and shows the excellent bondability & reliability. For lamination processability, we improved the transparency of NCF in order to recognize the dicing pattern or alignment marks on wafer through NCF. As a result, NCF-laminated wafer can be diced simultaneously and smoothly. For the bondability, the use of the high heat-resistant components and the optimization of the hardenability and viscosity made it possible to form the excellent bonding part and fill the narrow gap between chip & substrate without voids even at the high temperature condition (>300 degC for 1s) of Au-Sn eutectic bonding. For the reliability, we found that a kind of antioxidant prevented remarkably the electrochemical migration at finer pitch wiring and we confirmed the good electronic insulation property up to 25 μm pitch. Furthermore, the addition of the flux component into NCF enabled Cu-solder bonding. From these features, this NCF is expected to be a promising material for the high density electronic packages including 3D package with TSV (Through Silicon Via) [1–3].