Improving aluminum nitride plasma etch process for MEMS applications

Improving aluminum nitride plasma etch process for MEMS applications
Title:
Improving aluminum nitride plasma etch process for MEMS applications
Other Titles:
Journal of Micromechanics and Microengineering
Keywords:
Publication Date:
27 September 2013
Citation:
Abstract:
We present a new plasma etch process optimized for etching piezoelectric aluminum nitride (AlN) film deposited on thin molybdenum (Mo) metal electrode. Such film stack finds application in the integration of AlN-based RF microelectromechanical systems devices. The process is based on Cl2/BCl3/Ar gas chemistry with added buffer gas in inductively coupled plasma reactive ion etching system. The new gas mixture overcomes a generic problem of etched surface roughness without significant drop in AlN etch rate. Using design of experiment, the process window is optimized for improving selectivity to Mo and reducing microtrenching while maintaining smooth etched surface. Finally, an etching rate of 280 nm min−1 with reliable etch stop on Mo electrode and smooth bottom surface is reported. The integration suitability of the developed etch process is tested by etching 2.0 to 5.0 µm size square shaped via holes in 1.0 µm thick (0 0 2) oriented piezoelectric AlN on 0.2 µm thick Mo electrode while integrating contour mode resonators.
License type:
PublisherCopyrights
Funding Info:
Description:
ISSN:
0960-1317
Files uploaded:

File Size Format Action
pub13-016-mems-002.pdf 1.12 MB PDF Open