Primaxx Vapor HF Release for Oxide MEMS Structures at Cornell
Vincent Genova, CNF Process Engineer
Posted Oct. 2012
The recently installed Primaxx uEtch vapor HF system is a valuable addition to CNF’s process capabilties. The system provides a single step release process of MEMS structures without stiction or the use of critical point drying. The dry release process allows for highly selective and uniform etching of silicon dioxide (SiO2). Undercut etch rates as high as 0.25um/min can be obtained along with high selectivity to materials such as single crystal silicon, amorphous silicon, Al, TiW, Al2O3, and SiC. In addition, high selectivity to both LPCVD low stress silicon nitride and LPCVD stoichiometric silicon nitride has been demonstrated with figures as high 80:1 and 10:1 respectively. The figure at the right illustrates the successful release silicon beams 25um in length and 500nm in width from a silicon on insulator wafer (SOI) with a 2um thick buried oxide layer.
For additional information or training on the Primaxx system, please contact Vince Genova at Genova @cnf.cornell.edu.