A Self-Corrected, Self-Cleaned MEMS and Suitable for Advanced Foundry Multi-Project Wafer (MPW)

This work simplifies sacrificial-oxide (SOX) etching related implications (undercut and stress) in released MEMS that remains a leading process concern. Herein, SOX etch-time and stress-part get relaxed simultaneously simply by exposing MEMS chips to nanosecond (ns) laser before final SOX-etching (releasing). Therefore, > 80% stress-recovery in residue bending-correction, 6× extended etching window in undercut-correction, and for robust SOX etch-front and the direct cleaning feasibility of SOX’s residues is the first of its kind. Applied method yields ~ 66% direct reduction in pull-in voltage (21-to-7 volt). Verified self-corrected/self-cleaned feature added advantage to released MEMS as no extra fabrication preventing measures (deposition/patterning) required, unlike past fabrication attempts. The presented method can be applied directly in MPW like foundry manufacturing to reduce undercut/stress and related yield loss.