低温等离子体是芯片制造过程中刻蚀工艺的重要媒介物，也是刻蚀机腔室多场耦合分析与优化设计的主要研究对象。本文以感应耦合等离子体（ICP）刻蚀机为研究对象，通过流体动力学模拟方法，深入分析了腔室中流场和等离子体特性的空间分布以及关键结构和工艺参数的影响规律，并研究了基于多场耦合分析的刻蚀机优化设计方法。中性气体流场特性和等离子体特性的空间分布是影响刻蚀工艺效果的重要因素，是腔室与线圈结构以及工艺条件参数综合作用的结果。建立并验证了真空腔室可压缩理想气体流场模型，并分析了进气流量、腔室高度、腔室半径以及进气口半径对流场分布的影响，指出腔室高度对气压分布均匀性影响较大。建立并验证了标准实验平台GEC/ICP的两种等离子体多场耦合模型，一种是CFD-ACE+模型，一种是基于COMSOL的直接耦合求解偏微分方程组的流体动力学模型。后者考虑了电子与中性粒子的弹性碰撞能量损失，并提出了自洽的功率沉积机制，具有完全的开放性，在等离子体作用机理研究等方面潜力巨大。对实际用于90~65nm工艺的300mm多晶硅刻蚀机进行了建模仿真，并分析了关键工艺参数和结构参数分别对电子温度和电子数密度分布的影响。研究发现，随着气压和功率的增加，电子数密度升高；而电子温度则随气压增加而降低，随功率变化不明显。结构参数中屏蔽板、Focus Ring、腔室构型和腔室高度对等离子体特性空间分布有一定影响，而腔室半径和线圈构型是最重要的影响因素。引入回归正交试验设计方法，利用流场及等离子体仿真分析技术，建立多组模拟试验，对影响腔室中气压与等离子体分布的工艺与结构参数进行了灵敏度分析，并求得相应的回归方程。在回归方程基础上，运用一般约束优化方法搜寻满足气压和等离子体特性分布均匀度的最优参数空间，提出了扫描进气流量变化域以及参数空间分析的结构优化方法。
Low temperature plasma, as the main research object of multi-fields coupling analysis and optimization design for the chamber of the etcher, is an important medium by which chips are etched. Focusing on inductively coupled plasma (ICP) etchers, this thesis conducts the following research: fluid dynamics simulations are implemented to investigate spacial distributions of gas flow and plasma in chambers and key structure parameters and key process parameters’influences on those properties, and methods of optimization design of etchers based on multi-fields coupling analysis are then proposed.The important factors that affect etching results are spacial distributions of neutral gas flow and plasma, which are complicatedly domained by processes and structures of chambers and coils. Compressable ideal gas models of vacuum chambers are built and verified experimentally. By analyzing the influences of mass flow rate, height and radium of chamber, and raium of injet on the gas flow, it is concluded that the chamber’s height has more effects on the uniformity of pressure distribution.Two plasma multi-fields coupling models of the standard experimental platform, GEC/ICP, are built and proved efficiently. One is a CFD-ACE+ model, and the other is a fluid dynamics model which directly solves partial differential equations based on COMSOL. Elastic collision energy loss between electron and neutral particle is considered and a self-consistent mechanism of power deposition is taken into account in the latter model. Therefore, exclusively-opened COMSOL model is of great potential in the study of plasma reaction principle.A 300mm etcher which is used in 90~65nm polysilicon etching process is simulated to investigate the influences of key process and structure parameters on the spacial distributions of electron temperature (ET) and electron number density (END). It is implied that END increases with both pressure and power, while ET decreases obviously with pressure but slightly with the change of power. Although shielding slab, focus ring, chamber configuration and chamber height of structure factors all have some influences on plasma distribution, comparably chamber radium and coil configuration are the most important factors.A number of simulation experiments are setup by introducing regression orthogonal experiment design method and the technology of fluid and plasma simulation to analyze the sensitivity of process and structure parameters which affect pressure and plasma distribution in the chamber, and the regression equations are obtained. The regression equations from simulation experiments are optimized with general constrains to obtain the optimum parameters space which can meet the uniformity of pressure and plasma. Finally, a structure optimization method scanning gas flow rate in legal range and parameters space analysis is proposed.
