High selectivity in dry etching of silicon nitride over Si using a novel hydrofluorocarbon etch gas in a microwave excited plasma for FinFET

Y. Nakao, T. Matsuo, A. Teramoto, H. Utsumi, K. Hashimoto, R. Kuroda, Y. Shirai, S. Sugawa, T. Ohmi

Research output: Contribution to journalConference articlepeer-review

4 Citations (Scopus)

Abstract

Increased etch selectivity of SiNx over Si is required for the gate spacer formation in miniaturized MISFETs, especially in the FinFET. In this work, the selectivity of SiNx over Si is evaluated using a novel hydrofluorocarbon etch gas with a microwave excited high-density plasma. By using this novel etchant gas, a higher selectivity of SiNx over Si was obtained compared to CH3F. The etch rate of Si was suppressed due to the deposition of a hydrocarbon film on Si surface without O2 gas. It was found that the selectivity of SiNx over Si near the SiNx sidewall decreased compared that far from the SiNx sidewall. By using flow rates of more than 12 sccm of the novel CxHyFz gas, the gate spacer was formed without Si recess even after the SiNx was overetched for an equivalent thickness of 40 nm.

Original languageEnglish
Pages (from-to)29-37
Number of pages9
JournalECS Transactions
Volume61
Issue number3
DOIs
Publication statusPublished - 2014
EventInternational Symposium on Silicon Compatible Materials, Processes, and Technologies for Advanced Integrated Circuits and Emerging Applications 4 - 225th ECS Meeting - Orlando, United States
Duration: 2014 May 112014 May 15

ASJC Scopus subject areas

  • Engineering(all)

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