磁控溅射源中氩辉光放电的等离子体行为及分布特性

Plasma Behavior and Distribution Characteristics of Argon Glow Discharge in Magnetron Sputtering Source

通过三维粒子数值模型对现有磁控溅射源结构中氩辉光放电的等离子体行为和分布特征进行了模拟,从而得到靶材利用率和能量利用率的信息。离子轨迹、离子能量和离子入射角分布的分析结果表明,由于电势的空间分布影响,放电电压从260 V增加到340 V,使得轰击离子比例从80%降低到67%。由于离子向靶材移动和远离靶材都会得到加速,过高的放电电压不利于提高能量利用率。另一方面,提高放电电压有利于离子以更高的平均动能撞击靶材,有利于提高溅射产额。因此,根据工作压力选择合适的放电电压是提高电源效率的有效途径。通过离子溅射位置分布与靶材实际侵蚀剖面图的对比,验证了仿真模型的可靠性,对磁控溅射源的优化设计具有一定的参考价值。

In this paper,a 3D Particle-in-Cell numerical simulation model of DC magnetron sputtering source based on an existing structure is built.By simulating plasma behavior and distribution characteristics of argon glow discharge in an existing magnetron sputtering source structure,information about target utilization efficiency and also power efficiency can be obtained.Analysis of ion trajectories,energy and incident angle distribution indicates that bombarding ion portion decreases from 80%to 67%with the discharge voltage increasing from 260 V to 340 V due to the spatial distribution of electric potential.Since ions can be accelerated both moving toward and away from the target,an over-high discharge voltage is not beneficial to increasing power efficiency.On the other hand,increasing discharge voltage facilitates ions to impact the target with higher mean kinetic energy,which is beneficial to increasing sputtering yield.Therefore,choosing a proper discharge voltage according to working pressure is an effective way to increase power efficiency.Since the reliability of the simulation model is verified by comparison of ion sputtering position distribution and target actual erosion profile,simulation and analyzing methods in this paper are useful for the optimization design of the magnetron sputtering source.