A Novel High Resolution Epoxy Based Dry Film Material for Wafer Level Packaging Application

Applications of a novel epoxy based dry film photoresist, PerMX3000, have been investigated in this work in case of 3D structure architecture, micro-fluid tunnel, and wafer surface molding. For different package level requirements, such material provides high resolution patterning ability for narrow pitch layout design; controllable side wall shape from positive slope to negative slope; good adhesion property with silicon, silicon dioxide, BCB, polyimide, and general UBM metals for RDL and bumping in wafer level package; high chemical resistivity with alkaline, organic alkaline, acidic solutions. Dry film type material even enlarges the compatibility for the purpose of wafer level packaging process. In this work, single layer and multi-layers stacking laminations were performed. Non-planar surface with over 30um topography differences can be laterally modified into 2um by over-lamination of PerMX3000 material. Furthermore, the material with low cross-link temperature and low shrinkage reduces wafer warpage concerned in thermal curing process. The demonstration results shows high expected potential and possibilities for new package demand in next generation.