Reactivity of CCl 4 plasma against SiO 2 surfaces

SiO 2 is etched considerably by a CCl 4 plasma at surface power densities of about 0.3 W cm −2 . This etching process is investigated by the SiCl 4 formation with aid of mass spectroscopy where final products of the etching process and the extracted ions were studied in dependence on time in a closed plasma volume. The primary step of the etching process is the activation of SiO 2 by the plasma involving breaking of siloxan bridges. The overall mechanism of the SiO 2 etching by the CCl 4 plasma is proposed in form ofThe rate limiting constants are k 0 and k 3 . The SiCl 4 formation is decreased or inhibited by an admixture of Cl 2 , H 2 , O 2 or CO to the CCl 4 plasma. CCl 4 ‐Plasmen führen zu einem Ätzangriff an SiO 2 ‐Oberflächen. Dieser Ätzprozeß ist bei Leistungsdichten an der zu ätzenden Oberfläche von > 0,3 W cm −2 deutlich über eine SiCl 4 ‐Bildung nachweisbar. Der Primärschritt ist eine Aktivierung der SiO 2 ‐Oberfläche durch das Plasma, die zu Bindungsbrüchen der Siloxanbrücken führt.