AVS 49th International Symposium
    Plasma Science Wednesday Sessions
       Session PS-WeM

Paper PS-WeM8
Effect of Carbon Based Polymer Formation on Process Stability in Polysilicon Etching

Wednesday, November 6, 2002, 10:40 am, Room C-105

Session: Conductor Etch II
Presenter: Th. Lill, Applied Materials
Authors: S. Xu, Applied Materials
S. Deshmukh, Applied Materials
Th. Lill, Applied Materials
O. Joubert, CNRS/LTM, France
Correspondent: Click to Email
High density plasma at low pressure has been used extensively in etching ultra-small feature devices to achieve precise critical-dimension control. In such a processing environment, plasma properties become significantly dependent on the wall condition of the reactor through plasma wall interactions. Commonly, halogen containing silicon oxides are deposited on the chamber walls during polysilicon etching. Recently, in-situ dielectric mask open or dielectric anti-reflective coating open steps are being used more frequently. These steps generate carbon based deposits on the chamber walls. Another source of carbon polymers are CF4 and other CxHyFz additives used in silicon etching to achieves good n/p etch behavior and dense/iso microloading. This paper extends previously published studies on the influence of polymer formation on the chamber walls to carbon based polymers. The effect of surface polymerization has been characterized by studying the variation of the plasma properties and process performance. Clean, oxide covered and carbon covered chamber wall are being compared in terms radical densities, plasma emission properties, etch rates, and critical gate dimensions. Effective approaches to reduce the impact of chamber wall on the plasma and process stability will be discussed.