The Impact of Thermal Shrinkage of Glass Carriers on Achieving Fine Pitch Wiring Through Fan-Out WLP/PLP Process

The impact of thermal shrinkage of glass used as fan-out carriers on achieving fine pitch wiring were investigated. Glasses with thermal expansion coefficient of around 6~8 ppm/K with and without alkali ions were tested. With using conventional soda-lime glass as the carrier material, it was indicated that the thermal shrinkage of glass possibly causes failure of interconnection with via hole at multi-layer RDL. With using non-alkali glass, it was estimated that the amount of thermal shrinkage is sufficiently small even if the line and space is 2 µm/2 µm.