Analyses of Reactive Plasma Dynamics by Particle Simulations

通过粒子模拟分析反应等离子体动力学

• 批准号: 11680484
• 负责人: HAMAGUCHI Satoshi
• 金额: $ 2.56万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11680484/
• 关键词: plasma processing; PIC-MCC; RF discharge; particle simulation; dual frequency discharge; capacitively coupled discharge

Plasma processing, such as thin-film formation and surface modification technologies based on reactive plasmas, is one of the most important technologies for the advanced electronics, including semiconductor chips and liquid-crystal displays. In the present research, we have employed particle simulations based on the Particle-in-Cell (PIC) and Monte-Carlo Collision (MCC) methods to analyze plasma-processing tools used in semiconductor manufacturing. The PIC and MCC methods are ideal for reactive plasma simulations as the former can resolve electron velocity distribution functions and the latter can determine chemical reaction rates using fundamental physical data such as reaction collision cross sections. In 1999, we have developed a PIC/MCC code to simulate capacitively coupled parallel-plate Ar discharges in 2D cylindrical geometry. As to collisions, we have included ionization, excitation, and elastic collisions for electron-neutral collisions, and charge exchange and elastic collisions for ion-neutral collisions. Currently the neutral gas is assumed to be uniform with the room temperature. In 2000, we have extended the simulation code to handle dual-frequency capacitively coupled discharges and also introduced external electrical circuits for realistic plasma processing tools. Furthermore, we have employed an acceleration scheme for ion dynamics calculations to increase efficiency of the simulation code. In our simulations we have observed that, in both single- and dual-frequency capacitively coupled discharges, as the gas pressure decreases, the electron heating mechanism changes from ohmic heating to collisionless heating, and the electron energy distribution function exhibits a bi-Maxwellian distribution due to the Ramsauer minimum of the elastic collision cross section for Ar.

等离子体加工技术是以反应等离子体为基础的薄膜形成和表面改性技术，是半导体芯片和液晶显示器等先进电子技术的重要组成部分。在本研究中，我们采用粒子模拟的基础上粒子在细胞（PIC）和蒙特-卡罗碰撞（MCC）的方法来分析等离子体加工工具中使用的半导体制造。PIC和MCC方法是反应等离子体模拟的理想方法，因为前者可以求解电子速度分布函数，而后者可以使用反应碰撞截面等基本物理数据来确定化学反应速率。在1999年，我们已经开发了一个PIC/MCC代码来模拟电容耦合平行板Ar放电在二维圆柱几何。至于碰撞，我们已经包括电离，激发和弹性碰撞的电子中性碰撞，电荷交换和弹性碰撞的离子中性碰撞。目前，中性气体被假定为与室温一致。在2000年，我们已经扩展了模拟代码，以处理双频电容耦合放电，也介绍了现实的等离子体处理工具的外部电路。此外，我们采用了加速计划的离子动力学计算，以提高效率的模拟代码。在我们的模拟中，我们已经观察到，在单频和双频电容耦合放电，随着气体压力的降低，电子加热机制从欧姆加热到碰撞加热的变化，和电子能量分布函数呈现双麦克斯韦分布由于拉姆绍尔最小值的弹性碰撞截面Ar。