低气压感性耦合等离子体源模拟研究进展  

Numerical investigation of low pressure inductively coupled plasma sources:A review

作　　者：张钰如 高飞 王友年 Zhang Yu-Ru;Gao Fei;Wang You-Nian(Key Laboratory of Materials Modification by Laser,Ion,and Electron Beams,Ministry of Education,School of Physics,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学物理学院,三束材料改性教育部重点实验室,大连116024

出　　处：《物理学报》2021年第9期33-49,共17页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11875101,11935005);辽宁省自然科学基金(批准号:2020-MS-114);中央高校基本科研业务费专项资金(批准号:DUT20LAB201,DUT21LAB110)资助的课题。

摘　　要：感性耦合等离子体源具有放电气压低、等离子体密度高、装置结构简单等优点,因此常被用于材料刻蚀及表面处理工艺中.为了深入了解感性耦合等离子体的特性及其与表面的相互作用,数值模拟成为了目前人们普遍采用的研究手段之一.针对具体问题,可以选择不同的模拟方法,如整体模型、流体力学模型、流体力学/蒙特卡罗碰撞混合模型、偏压鞘层模型、粒子模拟/蒙特卡罗碰撞混合模型等.其中,整体模型计算效率最高,常被用于模拟复杂的反应性气体放电.但整体模型无法给出各物理量的空间分布,因此二维及三维的流体力学模型,也得到了人们的广泛关注.在低气压等极端的放电条件下,由于电子能量分布函数显著偏离麦氏分布,则需要耦合蒙特卡罗碰撞模型,来精确地描述等离子体内部的动理学行为.此外,通过耦合偏压鞘层模型,还可以自洽地模拟鞘层的瞬时振荡行为对等离子体特性的影响.对于等离子体中的非局域及非热平衡现象,则需要采用基于第一性原理的粒子模拟方法来描述.最后对目前感性耦合放电中的前沿问题进行了展望.Inductively coupled plasmas have been widely used in the etch process due to the high plasma density,simple reactor geometry,etc.Since the plasma characteristics are difficult to understand only via experiments,the numerical study seems to be a valuable and effective tool,which could help us to gain an in-depth insight into the plasma properties and the underlying mechanisms.During the past few years,various models have been employed to investigate inductive discharges,such as global model,fluid model,fluid/Monte Carlo collision hybrid model,biased sheath model,particle-in-cell/Monte Carlo collision hybrid model,etc.Since the plasma parameters are volume averaged in the global model,which effectively reduces the computational burden,it is usually used to study the reactive gas discharges with a complex chemistry set.In order to obtain the spatial distribution,a two-dimensional or three-dimensional fluid model is necessary.However,in the fluid model,the electron energy distribution function is assumed to be Maxwellian,which is invalid under special discharge conditions.For instance,strong electric field and low pressure may result in non-Maxwellian distributions,such as bi-Maxwellian distribution,two-temperature distribution,etc.Therefore,a fluid/Monte Carlo collision hybrid model is adopted to take the electron kinetics into account.Besides,a separate biased sheath model is necessary to study the influence of the sheath on the plasma properties self-consistently.The particle-in-cell/Monte Carlo collision hybrid model is a fully kinetic method based on the first-principles,which could be used to investigate the non-local and non-thermal equilibrium phenomena.In conclusion,the numerical investigation of inductively coupled plasmas has a significant importance for plasma process optimization.

关 键 词：感性耦合等离子体 整体模型 流体力学模型 混合模型 偏压鞘层模型 粒子模拟 

分 类 号：O53[理学—等离子体物理]