溅射离子泵阳极筒-阴极板间距对抽气特性影响的数值研究

The Effects of Gap between Anode and Cathode of Sputter Ion Pump on Its Pumping Performance Based on Numerical Approach

建立了描述溅射离子泵抽气单元抽气特性的计算模型。采用商业软件COMOL Multiphysics,将等离子体模块、磁场模块、带电粒子追踪模块进行耦合,计算得到了阳极筒内潘宁放电特性参数、气体离子入射阴极板能量和角度。引入非垂直入射溅射产额公式,计算得到阳极筒内壁溅射产额及抽气单元抽速。模拟计算结果与实验数据的对比表明,两者具有较好的一致性,验证了所建模型的适用性。基于所建计算模型,开展了溅射离子泵阳极筒-阴极板间距对抽气性能影响的数值研究。计算结果表明,阳极筒与阴极板间距对抽气单元的有效抽速有显著影响,并存在最优间距,该间距下抽气单元的抽速最大,同时最优间距随阳极筒半径增加而增大。基于模拟结果,提出了非等径、非等高阳极筒抽气单元阵列结构离子泵设计方案,为溅射离子泵的结构改进和性能优化提供了新的设计思路和可行路径。

A numerical modelling is proposed to calculate the pumping performance of sputter ion pump(SIP). The discharge parameters in Penning cell,sputtering ion energy and angle are obtained by COMOL Multiphysics plasma mode coupled with electromagnetic field mode. The sputtering yield and pumping speed of a Penning cell are calculated based on the sputtering yield semi empirical formalism. The numerical calculation results agree well with the experimental data,which shows that the present numerical modelling is validated. The effects of gap between anode and cathode of SIP Penning cell on the pumping performance is studied by the numerical method. The simulation results shown that the gap between anode cell and cathode plate is an important factor effected on the effective pumping speed. The effective pumping speeds increase first and then decrease as the gap increases. There is a gap between anode and cathode make pumping speed get peak value,which will be large as the radius of anode cell increases. A new SIP structure composed of different height and radius Penning cells is improved to optimize the pumping performance.