Heidelberg 1999 – scientific programme

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P: Plasmaphysik

P 21: Plasmatechnologie (Poster)

P 21.6: Poster

Monday, March 15, 1999, 16:30–19:00, PY

Studies of Oxide Etching Processes in Different Fluorocarbon Plasmas — •Harald H. Richter, Andre Wolff, Dietmar Krueger, and Rainer Barth — Institute for Semiconductor Physics Frankfurt (Oder); W.-Korsing-Str. 2, 15230 Frankfurt (Oder)

Processing of advanced integrated circuits requires a lot of plasma etching steps. Oxide etching will probably be one of the most critical processes for the next device generations. Due to the increase in aspect ratio, it is becoming more and more difficult to find a compromise between a high selectivity to underlayer and/or photoresist, and the absence of etch stop. We report a study of the application of different C_xF_yH_z discharges to SiO₂ contact etch. In particular, CHF₃/C₂F₆ and C₄F₈/CO₂ discharges will be compared with each other for plasma etching suitability in quarter micron technologies. It was found that gas flows play an important role for etch stops. Moreover, highly selective processes were achieved by H₂ addition to fluorocarbon plasmas. Diagnostics of fluorocarbon radicals and fluorine atom species were carried out using optical emission spectroscopy (OES). An increase in oxide selectivity is caused by enhanced CF radical concentration detected in OES spectra.