大直径直拉硅单晶等径的PID参数优化

Optimization of PID Control Parameters for Large Diameter Silicon Crystal Growth

随着国内硅材料应用技术不断发展,在大直径单晶的直径生长控制方面除了在设备上采用更加先进的双CCD系统,同时也对单晶生长的直径PID提出了更加严格的要求,因此研究单晶生长的直径PID参数设置有着重要意义。以等径阶段PID参数设置为研究对象,采用晶体生长的实验方法研究了不同PID参数控制对晶体生长的影响,分析了不同参数的作用,最终获得了大直径CZ硅等径生长的优化PID控制参数。实验选用TDR-150型单晶炉,Φ700 mm热场系统,一次性投入200 kg多晶硅,拉制目标直径400 mm的大直径硅单晶。从实验中可以分别得到4条晶体生长等径过程中直径波动曲线以及4张等径过程中实际拉速及晶体生长速率波动图。通过对比分析,实验确认了PID 3个参数(P值比例增益,D值微分,I值积分)的合理取值范围及其作用效果:应使P值在系统具备较高灵敏度和稳定控制的平衡点;使D部分在系统频率特性的中频段,以改善系统的动态性能;而使I值在系统频率特性的较低频段,以提高系统的稳态性能,同时又能够作用于长期控制。

With the development of large diameter silicon crystal growth technology,in addition to introduce more advanced double CCD system for the diameter control during large diameter crystal growth,the more precise PID control system was also required.So it was important to study the parameters of PID control.The PID control parameters during body growth process of CZ silicon were studied,the effects of PID on crystal growth was discussed and parameters were optimized for large diameter crystal growth.In the expe...