Metallization Technologies on a Smooth Resin Surface for the Next Generation of Flip Chip Packaging

Abstract

To realize higher wiring density, both finer line/space resolution and a smoother resin-metal interface are needed. These requirements, however, conflict to each other: sufficiently fine lines are difficult to form on a rough surface, while a smooth surface generally results in poor peel strength. The feasibility of various metallization processes that promote adhesion on smooth resin surfaces is examined. Their practical applicability to manufacturing high wiring-density packages is also assessed and the related issues that need to be improved are discussed.