Flexible integration of MEMS and IC for low-cost production of wireless sensor nodes

In this paper, we proposed a flexible process for size-free MEMS and IC integration with high efficiency for MEMS ubiquitous applications in wireless sensor network. In this approach, MEMS and IC can be fabricated individually by different wafers. MEMS and IC known-good-dies (KGD) are temporarily bonded onto carrier wafer with rapid and high-accurate self-alignment by using fine pattern of hydrophobic surface assembled monolayer and capillary force of H ₂O; and then KGD are de-bonded from carrier wafer and transferred to target wafer by wafer level permanent bonding with plasma surface activation to reduce bonding temperature and load force. By applying above 2-step process, size of both wafer and chip could be flexible selected. Besides, CMOS processed wafer or silicon interposer can be used as the target wafer. This approach offers us excellent process flexibilities for low-cost production of wireless sensor nodes.