Microelectronic Engineering 57–58 (2001) 599–605 www.elsevier.com / locate / mee Simulation of fluorocarbon plasma etching of SiO structures 2 a,b, a b * G. Kokkoris , E. Gogolides , A.G. Boudouvis a Institute of Microelectronics, NCSR ‘‘ Demokritos’’, Aghia Paraskevi, Attiki, Greece 15310 b Department of Chemical Engineering, National Technical University of Athens, Zographou Campus, Attiki, Greece 15780 Abstract A surface model for open area etching of SiO is coupled with a model to calculate the local values of etching rate on 2 each elementary surface of the structure being etched. The surface model includes the surface chemistry for ion-enhanced etching or deposition. The local etching model (essentially a local flux calculation model) includes shadowing effects of ions / neutrals and re-emission, while charging effects are simulated only by an increased ion angular spread. Aspect ratio dependent and independent etching as well as transition from etching to deposition are predicted and studied as a function of plasma phase composition. Variations of etching yield versus aspect ratio can be graphically depicted as paths on the two dimensional plot of equal yield contours versus the normalised fluorine and carbonaceous radicals flux. Operation regimes of the plasma allowing minimisation of aspect ratio dependent phenomena can be easily identified by such graphical representation.  2001 Elsevier Science B.V. All rights reserved. Keywords: SiO etching; Plasma etching; Aspect ratio dependent etching 2 1. Introduction Etching of SiO structures in fluorocarbon plasmas is a frequently encountered process in 2 microelectronics fabrication (i.g. etching of contact holes). Etching rates of SiO features have been 2 observed to depend on aspect ratio (AR) of the feature (the ratio of depth to width of the feature) rather than the absolute feature size. This scaling of etching rates to aspect ratio is described by the term aspect ratio dependent etching (ARDE). ARDE includes phenomena such as reactive ion etching lag (RIE lag), etch stop and transition from etching to deposition, and inverse RIE lag. The goal to achieve is aspect ratio independent etching (ARIE). There have been experimental results [1] and modeling efforts [2,3] showing that ARIE could be accomplished, at least for a range of feature depths. The purpose of this work is to explore the surface reaction effects, as well as near surface ion and *Corresponding author. Tel.: 130-1-650-3237; fax: 130-1-651-1723. E-mail addresses: gkok@imel.demokritos.gr (G. Kokkoris), evgog@imel.demokritos.gr (E. Gogolides), boudouvi@chemeng.ntua.gr (A.G. Boudouvis). 0167-9317 / 01 / $ – see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S0167-9317(01)00549-4