磁控溅射镀膜中钛靶冷却系统的仿真与优化

Simulation and Optimization for the Titanium Target Cooling in Magnetron Sputtering Coating

在磁控溅射镀膜过程中,纯钛靶材会在辉光放电中受到离子轰击而迅速升温,可能会导致靶材或永磁体等关键部件毁坏,为保证钛靶的正常工作温度以及溅射过程的稳定性,需要通过水冷等方式来降温。为了研究水冷过程中不同冷却结构对钛靶换热效率的影响,从增大换热面积和增加水流的湍流效果出发设计冷却通道结构,通过改变水流入口速度以及进出口的方向来获得最优的冷却系统结构。结果表明:平面冷却通道的换热效果优于蛇形冷却通道,且钛靶表面凸起结构能有效增加水流湍流效果;对于任意冷却结构来说,随着入口水流速度的增加,钛靶表面最高温度明显降低;水流进出口沿着冷却内腔切向方向且呈相对平行时,冷却系统的换热效果最优,钛靶表面温度分布也更为均匀。

In a magnetron sputtering system, the temperature of Ti target will increase rapidly under the action of ion bombardment during the process of glow discharge, and maybe destroy the key components, such as target or permanent magnet. To make an ideal temperature environment available for the Ti target and the sputtering process, the cooling system should be set to decrease the temperature of Ti target. To compare the heat transfer effectivity with different cooling system structures, different cooling water path structures were established with large heat transfer area and con- ducive to increase the flow turbulent. By changing the water velocity of inlet and the direction between inlet and outlet of water flow, the optimal structure of cooling system could be obtained. The results show that the plane structure is prefer to the snakelike structure in cooling performance, and the bump structure added on the target surface can greatly enhance the effect of water turbulence. For any kind of structure, cooling effect is greatly improved by increasing the water velocity of inlet. Also, the results show that the temperature distribution of Ti target surface is best when the inlet and outlet are in a relative parallel position and the cooling water flow along the tangential direction of chamber wall.