Dry vapor etch utilising HF or XeF2 is used for the isotropic etch removal of sacrificial silicon or oxide layers to release flexures or other MEMS devices with enhanced selectivity and without stiction. This provides controlled, residue-free etching across a wide range of etch rates.
Key applications for vapor release technology include inertial sensors, mirror arrays, resonators, RF MEMS, micro-actuators and microphones.
Benefits of SPTS Dry Vapor Release
- Eliminates stiction
- Low attack on a wide range of device and mask materials
- Repeatable, stable performance with a wide process window
- Compatible with a wide range of metals, especially unprotected aluminium (Al) mirrors and bond pads
- No complex waste management issues, small footprint, no process consumables
- Low cost of ownership compared with wet bench technology
- Reduced pressure operation keeps etch by-products in the gas phase ensuring high selectivities to metals and maximum feature penetration
Released silicon mirror
(Courtesy of Fraunhofer IPMS)
Released thin silicon wire waveguide
(Courtesy of Assoc. Prof. Kanamori,