Düsseldorf 2007 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
P: Fachverband Plasmaphysik
P 16: Poster
P 16.26: Poster
Mittwoch, 21. März 2007, 16:30–18:30, Poster A
Etch Stop Phenomena in Deep Trench Silicon Plasma Etching For Sub-100nm Technologies — •Harald Richter1, Siegfried Günther1, Günter Weidner1, Stephan Wege2, Sven Barth2, Steffen Marschmeyer1, Heike Silz1, and Ioan Costina1 — 1IHP Frankfurt (Oder) — 2Qimonda Dresden
Plasma etch processes are key technological steps in fabrication of semiconductor devices. The process development is driven by ultrahigh-density structures such as DRAM memories. The shrink of lateral dimensions at approximately constant capacity specifications leads to increased deep trench aspect ratios.
In this paper we describe deep trench process development focused on hard mask investigation. These investigations are driven by the following motivation: To realise high aspect ratios requirements high selectivity to etch mask and excellent uniformity are needed. Therefore, better knowledge of hard mask consumption during Si etching and sidewall passivation mechanisms are necessary. Investigations were focused on a hard mask consisting of oxide layer on TiN.
A common deep trench etch process using HBr/NF3/O2 leads to an etch stop in Si as soon as the oxide mask is consumed completely and TiN mask is exposed to plasma. A thick passivation layer at trench bottom was detected. The chemical analysis of the bottom region shows a significant Ti concentration causing etch stop. The influence of different plasma parameters (power, pressure, cathode temperature and gas additives) to overcome this unrequested etch stop phenomenon will be discussed.