High etch selectivity for plasma etching SiO2 with AlN and Al2O3 masks

Kai Kolari

Research output: Contribution to journalArticleScientificpeer-review

27 Citations (Scopus)


SiO2 has been etched with high etching selectivity to Al2O3 and AlN masks using inductively coupled plasma. This offers a possibility to use very thin masks for deep etching of glass for e.g. microfluidic devices. Furthermore, SiO2 can be etched with very low etching selectivity to the mentioned masks, indicating a possibility to pattern the Al2O3 and AlN with SiO2 or photoresist mask. A process based on a mixture of SF6 and C4F8 was observed to etch SiO2 with a rate of about 100 nm/min at 250 V bias (peak-to-peak) voltage, when Al2O3 and AlN had a zero etch rate. A process based on pure C4F8 was observed to etch Al2O3 and AlN with about 350 V bias, when SiO2 etch rate was still zero.
Original languageEnglish
Pages (from-to)985-987
JournalMicroelectronic Engineering
Issue number5-6
Publication statusPublished - 2008
MoE publication typeA1 Journal article-refereed


  • Plasma etching
  • Glass
  • Selectivity
  • Aluminium nitride
  • Aluminium oxide


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