摘要
为满足高分辨率光刻机控制大时间热响应常数投影物镜温度时响应速度和超高精度的要求,设计了前馈——串级水冷投影物镜温控系统。该系统以物镜为主控对象、冷却循环水为副控对象。针对物镜的慢动态温度变化特征,采用模型预测控制作为外环主控制算法;针对冷却水远传回路的纯时滞特性,采用带Smith预估器的PID控制作为内环副控制算法;为解决光刻机在不同工况下激光光路对物镜温度的严重扰动,引入前馈补偿控制激光热扰动。最后,在不同控制结构和热干扰条件下,进行了模拟物镜温度控制实验。结果显示,物镜温度稳态误差曲线在±0.01℃内波动。实验证明该系统极大地提高了物镜的温度收敛速度,具有较强的抗干扰能力,能满足物镜的超高精度温度控制要求。
A feedforword-cascade water cooling control system is presented to meet the requirements of a projection lens in a high-resolution optical lithography for the fast convergence and high performance temperature control. The system takes an objective as the primary control object and the cooling water as a secondary control object. According to the slow dynamic temperature response characteristics of the projection lens, model predictive control is adopted as the outer loop main control algorithm. On the basis of the large time-delay problems of a cooling water circuit, the PID control with a Smith pre- dictor is used as the inner loop auxiliary control algorithm. To overcome the serious disturbance in op- tical lithography at different operating status, the feedforward compensation is introduced to control the laser thermal interference. Finally, the temperature control experiment for the objective is simula- ted under the conditions of different control structures and thermal interferences. The results show that the stable-state error curve of the objective is in the ±0.01 ℃. The control experimental results demonstrate that the method has fast convergence and strong anti-interference, and meets the requirements of the projection lens for ultra-precision temperature control.
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2013年第1期108-114,共7页
Optics and Precision Engineering
基金
国家02专项基金资助项目(No.2009ZX02005)
关键词
投影物镜
温度控制
串级控制
大时滞
模型预测
前馈补偿
projection lens
temperature control
cascade control
long time delay
model prediction
feedforward compensation
