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P: Plasmaphysik
P 4: Diagnostik 1; Niedertemperaturplasmen / Plasmatechnologie 2; Magnetischer Einschluß 2
P 4.25: Poster
Monday, March 27, 2006, 17:00–19:00, Flure
Carbon Plasma Etching in Advanced Semiconductor Technologies — •Harald H. Richter1, Kevin A. Pears2, Matthias Markert2, Steffen Marschmeyer1, Siegfried Günther1, Günter Weidner1, and Heike Silz1 — 1IHP Frankfurt; Im Technologiepark 25, 15236 Frankfurt (Oder) — 2Infineon Technologies Dresden
Amorphous hydrogenated carbon films are showing promise as future hard mask candidates for plasma etch applications in semiconductor manufacturing. We present plasma etching results for a dual-layer stack consisting of a thin (25-50nm) SiON film on top of a thicker (200nm) carbon layer. The paper discusses results of process development for different etch chemistries using a magnetically enhanced plasma etch reactor. The basic idea for HBr/He-O2/N2 plasma choice was the availability of a carbon etchant (O2) and simultaneous passivation components (HBr and N2). Our pattern transfer process provides excellent results for profile control and etch selectivities to SiON top layer. The resulting bowing-free carbon profiles are almost vertically with a small taper and are very stable against long over etch steps. Thus, the tendency to lateral etching leading to profile loss seems to be much lower in comparison to other common carbon etch chemistries. It appears that the passivation from HBr/He-O2/N2 did not stick to itself very well but sticked to carbon very well. Therefore, in further experiments a carbon precursor (C2H2) was added to modify the chemical composition of the passivated surface and leads to a better sticking side wall passivation.