The Physics of Plasma-Induced Charging Damage

ECS-9729968 GiapisPatterned表面经常暴露在等离子体中，就像在等离子体表征中通过微小取样孔或在从微电子中的蚀刻、沉积和灰化到选择性表面功能化的应用中一样。通常，图案由不同的材料(绝缘掩模、导电金属或多晶硅、栅极和场氧化物)组成，由于等离子体鞘出口处离子和电子之间的方向性差异而充电。等离子体感应充电可能会导致离子偏转，导致不良后果；例如，掩模充电导致在刻蚀高深宽比特征时侧壁轮廓不规则。在这项提议中，我们试图通过一种实验和理论相结合的方法来揭示等离子体感应充电的基本物理原理，该方法侧重于绝缘体和导体的致密亚微米图案，类似于等离子刻蚀中遇到的图案。大规模的蒙特卡罗模拟将结合鞘动力学、微结构充电、静电学、反应、散射、通过绝缘体的电子隧穿和表面电流来揭示关于等离子体参数对充电损伤的影响的各种相互矛盾的报告。特别是，我们试图了解所谓的“电子遮蔽”损伤的性质，这种损伤会导致灾难性的电子隧道电流通过绝缘体上多晶硅结构中的栅氧化物。模式相关充电效应的大量建模工作将被扩展到包括隧道效应和表面电流，并将被用于预测：a)电子温度、射频偏置和射频频率对充电损伤的影响。b)长宽比相关的充电效应。微负载和电子阴影之间有关联吗？c)掩膜厚度效应。使用较薄的硬(氧化物)面具将如何影响充电损害？d)特征和晶片规模的影响。对某一特定特征的充电是否会影响邻近战壕的伤害？为什么脉冲等离子体可以减少这两种形式的充电损伤？F)消除充电损伤的新器件布局规则。模拟结果将通过在螺旋谐振器中产生的高密度等离子体中的大量刻蚀实验来验证

ECS-9729968GiapisPatterned surfaces are frequently exposed to plasmas as in plasma characterization through minuscule sampling orifices or in applications ranging from etching, deposition, and ashing in microelectronics, to selective surface functionalization. Frequently, the patterns consist of dissimilar materials (insulating masks, conductive metal or polysilicon, gate and field oxide), which charge up as a result of the directionality difference between ions and electrons at the plasma-sheath exit. Plasma-induced charging may cause ion deflection with undesirable consequences; for example, mask charging leads to sidewall profile irregularities when etching high aspect ratio features. In this proposal, we seek to reveal the fundamental physics of plasma-induced charging through a combined experimental and theoretical approach focused on dense sub-micron patterns of insulators and conductors similar to those encountered during plasma etching. Large-scale Monte Carlo simulation will combine sheath dynamics, microstructure charging, electrostatics, reactions, scattering, electron tunneling through t n insulators, and surface currents to shed light into a variety of conflicting reports on the influence of plasma parameters on charging damage. In particular, we seek to understand the nature of the so called "electron shading" damage, which causes catastrophic electron tunneling currents through the gate oxide in polysilicon-on-insulator structures. Significant modeling effort on pattern-dependent charging effects will be expanded to include tunneling effects and surface currents and will be used to predict:a) The influence of electron temperature, rf bias, and rf frequency on charging damage.b) Aspect-ratio-dependent charging effects. Is there a correlation between microloading and electron shadowing?c) Mask thickness effects. How will the use of thinner hard (oxide) masks impact charging damage?d) Feature- and wafer-scale effects. Does charging of a particular feature affect damage in neighboring trenches?e) Pulsed-plasma effects. Why do pulsed plasmas reduce both forms of charging damage? f) New device-layout rules for eliminating charging damage.The simulation results will be validated by extensive etching experiments in a high density plasma produced in a helical resonator