Inkjet-printed microshell encapsulation: A new zero-level packaging technology

A low-thermal-budget (CMOS-compatible) process for microshell encapsulation of MEMS devices is proposed. Inkjet-printing of silver (Ag) nanoparticle ink is demonstrated to form porous microshells through which sacrificial oxide (SiO2) can be selectively removed to release MEMS structures. A second inkjet printing process using finer gold (Au) nanoparticle ink is demonstrated to effectively seal the microshells. The mechanical strength of a printed microshell (~3 μm thick) is sufficient for encapsulating regions greater than 1 mm in length.