Publication detail

Infinite selectivity of wet SiO2 etching in respect to Al

GABLECH, I. BRODSKÝ, J. PEKÁREK, J. NEUŽIL, P.

Original Title

Infinite selectivity of wet SiO2 etching in respect to Al

Type

journal article in Web of Science

Language

English

Original Abstract

We propose and demonstrate an unconventional method suitable for releasing microelectromechanical systems devices containing an Al layer by wet etching using SiO2 as a sacrificial layer. We used 48% HF solution in combination with 20% oleum to keep the HF solution water-free and thus to prevent attack of the Al layer, achieving an outstanding etch rate of thermally grown SiO2 of ≈1 µm·min−1. We also verified that this etching solution only minimally affected the Al layer, as the chip immersion for ≈9 min increased the Al layer sheet resistance by only ≈7.6%. The proposed etching method was performed in an ordinary fume hood in a polytetrafluorethylene beaker at elevated temperature of ≈70 °C using water bath on a hotplate. It allowed removal of the SiO2 sacrificial layer in the presence of Al without the necessity of handling highly toxic HF gas.

Keywords

SiO2 etching; microelectromechanical systems (MEMS) ; sacrificial layer; selectivity

Authors

GABLECH, I.; BRODSKÝ, J.; PEKÁREK, J.; NEUŽIL, P.

Released

31. 3. 2020

Publisher

MDPI

Location

Basel, Switzerland

ISBN

2072-666X

Periodical

Micromachines

Year of study

11

Number

4

State

Swiss Confederation

Pages from

365

Pages to

371

Pages count

7

URL

https://www.mdpi.com/2072-666X/11/4/365

Full text in the Digital Library

http://hdl.handle.net/11012/186781

BibTex

@article{BUT163196,
  author="Imrich {Gablech} and Jan {Brodský} and Jan {Pekárek} and Pavel {Neužil}",
  title="Infinite selectivity of wet SiO2 etching in respect to Al",
  journal="Micromachines",
  year="2020",
  volume="11",
  number="4",
  pages="365--371",
  doi="10.3390/mi11040365",
  issn="2072-666X",
  url="https://www.mdpi.com/2072-666X/11/4/365"
}