不同工艺参数及喷淋板结构下PECVD热流场分析

Analysis of PECVD Heat and Flow Field under Different Process Parameters and Showerhead Structures

建立了PECVD腔室的连续流体和传热模型,通过仿真实验来分析工艺参数和喷淋板结构对PECVD腔室热流场的影响。在典型工艺的基础上,根据单变量原则设计不同的仿真实验来研究工艺参数对晶圆片上方流速、压力及温度分布的影响,结果显示在不同的工艺参数下,流速分布都能够保持线性分布;温度分布波动很小,表现良好的稳定性;压力随径向近似抛物线分布,中心压力高边缘压力低。另外本文设计了两组仿真实验,研究喷淋板不同的流阻分布对热流场的影响,结果显示喷淋板流阻的分布对流速分布有明显的影响,在不同的流阻分布下,加热盘边缘处的流速保持不变,但是流速分布存在一个拐点,拐点前和拐点后流速都近似于直线分布;结果说明能够通过改变喷淋板流阻的分布来调控晶圆上方流速的分布从而获得更高的薄膜工艺均匀性。

The PECVD reaction chamber＇s fluid and heat transfer model were established,the influence of process parameters and showerhead plate structures on the heat and flow distribution were studied. Based on the typical process parameters,simulations were designed according to single variable principle to study the influence of process parameters on the velocity,pressure and temperature distribution above wafer. The simulation results show that,under different process parameters： the distribution of velocity is linear with radius; the fluctuation of temperature is small and shows good stability; pressure is distributed approximately parabolic along with radius with higher pressure in the center. In addition,the effect of showerhead plate＇s flow resistance distribution on the heat and flow distribution were studied by designing two sets of simulations. The results show that the velocity on the edge of heat plate remains unchanged for different flow resistance distributions,but there is a turning point in the velocity distribution and velocity is linearly distributed before and after the turning point. So,it can be concluded that the velocity distribution above wafer can be controlled to acquire higher deposition uniformity by changing the flow resistance distribution of showerhead plate.