Thin substrate handling by electrostatic force

Abstract:
Efficient handling and processing of thinned Si-substrates becomes increasingly important for such technologies like 3D system integration, MEMS applications and advanced packaging and micro integration. Using suitable adhesives to bond device wafers temporarily to a rigid handling wafer can offer an efficient solution for 3D IC fabrication – if the material is satisfying a set of stringent requirements. In the future this may be replaced or at least supplemented by a novel handling technique that uses mobile electrostatic carrier ("mobile e-Chuck"), fabricated by processing a standard Si-wafer. The corresponding principle is based on electrostatic forces between the e-Chuck wafer, serving as a mobile handling substrate, and the thin device wafer or chips. The mobile e-Chuck is fully CMOS-compatible and it allows long duration times for electrostatic holding also after disconnecting a charging unit.