Mechanism of charging reduction in pulsed plasma etching

被引:35
作者
Hwang, GS [1 ]
Giapis, KP [1 ]
机构
[1] CALTECH, Dept Chem & Chem Engn, Pasadena, CA 91125 USA
来源
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS | 1998年 / 37卷 / 4B期
关键词
pulsed plasma; global models; Monte Carlo simulation; sheath dynamics; charging; etching; notching; charging damage; gate oxide degradation;
D O I
10.1143/JJAP.37.2291
中图分类号
O59 [应用物理学];
学科分类号
摘要
Numerical simulations of charging and etching in time-modulated high-density plasmas suggest a new mechanism for the reduction of pattern-dependent charging, which is based on low energy positive ions. During the power-off period and before the sheath collapses, the electron temperature and plasma potential decrease rapidly, resulting in low energy ions which can be deflected by smaller local electric fields. The nux of deflected ions to the upper mask sidewalls increases enabling neutralization of the negative charge accumulated there due to the electron shading effect. Current balance at the trench bottom surface is achieved at lower charging potentials, which lead to significantly reduced notching and gate oxide degradation. Pulsing period and duty ratio are examined as parameters to control the performance of pulsed plasmas.
引用
收藏
页码:2291 / 2301
页数:11
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