The Comparison of different Top Metal Materials in MEMS Applications

The combination of analog/mixed-signal, high-voltage and embedded non-volatile memory options with sensor and actuator integration is still common in automotive, industrial, communication and medical applications. MEMS with or without integrated CMOS, 3D integration micro transfer printing and integrated microfluid systems are in use to realize such applications. The established top metal interconnect materials for analog/mixed-signal CMOS applications are thick Aluminum (AlCu with Titan and Titanium Nitride) and thick Copper. Integrated noble metal electrodes are necessary for MEMS applications like microfluidics. The reliability requirements of a CMOS/ MEMS process differs from a long storage shelf life at room temperature, long life time for medical (in-body) or space applications up to high operating conditions for automotive and industrial applications like oil drilling. Applications, like functional surfaces, combine integrated circuits for example for next generation DNA sequencing. The noble metals for electrodes on top are thinner for such applications. An additional reliability challenge for such a lab on a chip is corrosion.