Wet etching of SiO2 as sacrificial layer with infinite selectivity to Al

Wet etching of SiO2 as sacrificial layer with infinite selectivity to Al

article in a collection out of WoS and Scopus

Czech

This work presents an unusual method for releasing microelectromechanical systems which contain an Al layer. This is done by wet etching of SiO2 as a sacrificial layer. Mixture of 49% HF acid and 20% H2SO4∙SO3 (oleum) is used. Oleum keeps the solution water-free and subsequently prevents the attack of Al layer. Exceptional etch rate (≈ 1 µm·min−1) of thermally grown SiO2 is achieved by this method. The infinite selectivity to Al layer is verified by measuring the thickness of layer before and after etching. The etching itself is done in an ordinary fume hood in polytetrafluorethylene (PTFE) beaker.

This work presents an unusual method for releasing microelectromechanical systems which contain an Al layer. This is done by wet etching of SiO2 as a sacrificial layer. Mixture of 49% HF acid and 20% H2SO4∙SO3 (oleum) is used. Oleum keeps the solution water-free and subsequently prevents the attack of Al layer. Exceptional etch rate (≈ 1 µm·min−1) of thermally grown SiO2 is achieved by this method. The infinite selectivity to Al layer is verified by measuring the thickness of layer before and after etching. The etching itself is done in an ordinary fume hood in polytetrafluorethylene (PTFE) beaker.

MEMS, selectivity, SiO2 etching, sacrificial layer

MEMS, selectivity, SiO2 etching, sacrificial layer

BRODSKÝ, J.; GABLECH, I.

27. 4. 2020

VUT

Brno, Czech Republic

978-80-214-5867-3

Proceedings of the 26th Conference STUDENT EEICT

292

295

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