The Physics of Plasma-Induced Charging Damage

图案表面经常暴露在等离子体中，如通过微小的采样孔进行等离子体表征或在微电子中的蚀刻，沉积和灰化到选择性表面功能化等应用中。通常，这些模式由不同的材料（绝缘掩膜、导电金属或多晶硅、栅极和场氧化物）组成，它们由于等离子体鞘出口离子和电子之间的方向性差异而充电。等离子体诱导的充电可能引起离子偏转，带来不良后果；例如，在蚀刻高纵横比特征时，掩膜充电会导致侧壁轮廓不规则。在这一建议中，我们试图通过结合实验和理论的方法来揭示等离子体诱导充电的基本物理原理，重点关注与等离子体蚀刻过程中遇到的类似的绝缘体和导体的密集亚微米模式。大规模的蒙特卡罗模拟将结合护套动力学、微观结构充电、静电学、反应、散射、电子穿隧穿过t n绝缘体和表面电流，揭示关于等离子体参数对充电损伤影响的各种相互矛盾的报道。特别是，我们试图理解所谓的“电子遮蔽”损伤的本质，它会导致灾难性的电子隧穿电流通过绝缘体上多晶硅结构中的栅氧化物。对模式相关充电效应的重要建模工作将扩展到包括隧道效应和表面电流，并将用于预测：a)电子温度、射频偏置和射频频率对充电损伤的影响。b)视宽比相关的充电效应。微负载和电子遮蔽之间是否存在关联？c)蒙版厚度效果。如何使用较薄的硬质（氧化物）掩膜冲击充电损伤？d)特征和晶圆规模效应。一个特殊功能的充电会影响相邻战壕的伤害吗？e)脉冲等离子体效应。为什么脉冲等离子体可以减少两种形式的充电伤害？f)新的设备布局规则，以消除充电损坏。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进行大量的蚀刻实验来验证

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