Deep lateral anhydrous HF/methanol etching for MEMS release processes

Meltem Erdamar; Karthikeyan Shanmugasundaram; Paul Roman; Paul Mumbauer; Maria Klimkiewicz; Jerzy Ruzyllo

doi:10.1117/1.2959177

1 July 2008 Deep lateral anhydrous HF/methanol etching for MEMS release processes

Meltem Erdamar, Karthikeyan Shanmugasundaram, Paul Roman, Paul Mumbauer, Maria Klimkiewicz, Jerzy Ruzyllo

Journal of Micro/Nanolithography, MEMS, and MOEMS, Vol. 7, Issue 3, 033014 (July 2008). https://doi.org/10.1117/1.2959177

Abstract

As demonstrated earlier, gas-phase etching of sacrificial oxide with a vapor mixture of anhydrous HF (AHF) and methanol (CH₃OH) offers a clean, stiction-free, effective etching technique for microelectromechanical systems (MEMS) release. The use of AHF/methanol process in MEMS release operations is explored in the deep lateral etching of patterned silicon-on-insulator (SOI) substrates using a 200 mm multiwafer commercial module, which assures adequate process throughput. It was determined that highly selective, with respect to both Si and Si₃N₄, etching of SiO₂ can be accomplished by controlling pressure and wafer temperature. It was also observed that the vertical etch rates for both the AHF/methanol and the HF: H₂O solution was higher than the rates of lateral etches in confined geometries. Furthermore, the AHF/methanol and 1:10 HF: H₂O etch chemistries were directly compared in releasing silicon cantilevers up to 500 µm in length and a significantly faster, stiction-free process was observed in the former case. Adequate process reproducibility from wafer to wafer as well uniformity across the wafer was demonstrated.

©(2008) Society of Photo-Optical Instrumentation Engineers (SPIE)

Citation Download Citation

Meltem Erdamar, Karthikeyan Shanmugasundaram, Paul Roman, Paul Mumbauer, Maria Klimkiewicz, and Jerzy Ruzyllo "Deep lateral anhydrous HF/methanol etching for MEMS release processes," Journal of Micro/Nanolithography, MEMS, and MOEMS 7(3), 033014 (1 July 2008). https://doi.org/10.1117/1.2959177

Published: 1 July 2008

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