AVS 53rd International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS1-TuP

Paper PS1-TuP1
Influence of Redeposition on the Plasma Etching Dynamics

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Etching of High-K, Compound Semiconductors and Advanced Materials Poster Session
Presenter: J. Margot, Université de Montréal, Canada
Authors: L. Stafford, University of Florida
J. Margot, Université de Montréal, Canada
S. Delprat, INRS-Energie, Matériaux et Télécommunications, Canada
M. Chaker, INRS-Energie, Matériaux et Télécommunications, Canada
S.J. Pearton, University of Florida
Correspondent: Click to Email
The development of high-resolution pattern transfer processes is one of the critical issues related to the manufacturing of very large scale integrated circuits. As the feature size moves toward the nanometer scale, the commonly used trial/error method for the optimization of dry etching is clearly approaching its limit, and basic understanding of the plasma etching science has become crucial for process control. Basic understanding can be realized for example by developing rate and feature scale models which by comparison of their predictions to experimental data can provide insights into the plasma etching dynamics, and eventually suggest experimental conditions for reliable pattern transfer. In this presentation, we examine the influence of redeposition on the plasma etching dynamics using both experimental and modeling approaches. Redeposition of sputtered species is a common feature in plasma etching and usually leads to the formation of shallow sidewall angles and fences on the sidewall of etched profiles. Even though redeposition is known to play an important role in several plasma etching processes, no quantitative results on the influence of this phenomenon have been reported so far. This work reports on measurements of the redeposition degree during sputter-etching of Platinum (Pt), Barium-Strontium-Titanate (BST), Strontium-Bismuth-Tantalate (SBT), and Photo-Resist (PR) in a high-density argon plasma. While PR exhibits a redeposition-free behaviour, the redeposition degree of Pt, BST, and SBT increases from 10 to 90% as the argon pressure increases from 0.5 to 10 mTorr. The physical mechanisms yielding the observed redeposition effects are discussed. Based on these results and using other experimental data reported in the literature, it is demonstrated that, depending on the plasma etching conditions, redeposition effects can induce misinterpretation of the etch rate data. A rate model taking into account redeposition effects is proposed.