Chip to wafer temporary bonding with self-alignment by patterned FDTS layer for size-free MEMS integration

In this paper, we present a low-cost and rapid self-alignment process for temporary bonding of MEMS chip onto carrier wafer for size-free MEMS-IC integration. For the first time, a hydrophobic self-assembled monolayer (SAM), FDTS (CF₃(CF₂)₇(CH₂)₂SiCl₃), was successfully patterned by lift-off process on an oxidized silicon carrier wafer. Small volume of H₂O (~μl/cm²) was then dropped and spread on the non-coated hydrophilic SiO₂ surface for temporary bonding of MEMS chip. Our results demonstrated that the hydrophobic FDTS pattern on carrier wafer enables rapid and precise self-alignment of MEMS chip onto SiO₂ binding-site by capillary force. After transfer the MEMS chips to target wafer, FDTS can be removed by O₂ plasma treatment or UV irradiation.