Thin hermetic borosilicate glass layers for highly reliable chip-passivations in wafer-level-packaging

A technology yielding thin, hermetic borosilicate glass layers at high deposition rates and low substrate temperatures and its potentials for a novel approach on wafer-level passivation is described. The benefits of this CMOS-compatible technology are highlighted, comparing the achievable film characteristics to polymers commonly used for these purposes. The glass layer is deposited at low temperatures (T < 100degC) using a plasma-enhanced e-beam deposition and can be structured by a lift-off process using a standard photo resist process for masking. The process flow is fully compatible with standard CMOS post processing and is integrated in a state-of-the-art production environment.