The core sequence: A nanoscale fluorocarbon-free silicon plasma etch process based on SF6/O2 cycles with excellent 3D profile control at room temperature

Vy Thi Hoang Nguyen, Chantal Silvestre, Peixiong Shi, Roy Cork, Flemming Jensen, Jorg Hubner, Kechun Ma, Pele Leussink, Meint de Boer, Henri Jansen*

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    4 Citations (Scopus)

    Abstract

    This study focuses on the development of a fluorocarbon-free directional silicon etching process, called CORE (Clear, Oxidize, Remove, and Etch) in which a switching sequence of SF6 and O2 is operated at room temperature. This distinguishes it from the old-fashioned room temperature and cryogenic mixed RIE processes as CORE enables a higher selectivity, creates pattern independency of etching profiles and works excellent at room temperature. The CORE process resembles the well-known SF6-based Bosch process, but the usual C4F8 inhibitor is replaced by O2 oxidation with self-limiting characteristics. Therefore the CORE result is similar to Bosch, however has the advantage of preventing the pile-up of fluorocarbon deposits at the topside of deep-etched or nano-sized features. At the same time, process drift is minimized as the reactor wall is staying perfectly clean. The CORE process has shown an excellent performance in high aspect ratio (3D) nanoscale structures with an accurate and controllable etch rate between 1 and 50 nm min−1 (and SiO2-selectivity of ca. 35) using the etch-tool in the RIE-mode. By adding the ICP source (DRIE-mode), a directional etch rate up to 1 μm min−1 (at 50 sccm SF6 flow) and selectivity >200 for SiO2 is possible.

    Original languageEnglish
    Article number024002
    JournalECS journal of solid state science and technology
    Volume9
    Issue number2
    DOIs
    Publication statusPublished - 17 Jan 2020

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