硅片处理预对准系统的研究

Research on Wafer Pre-alignment System

介绍了所研制的12 in硅片预对准系统.首先,根据硅片预对准系统的任务和流程设计了系统的结构.其次,设计了预对准检测算法,采用最小二乘圆法对硅片圆心进行定位;提出了检测硅片缺口的边缘变化率法和计算缺口基准点的曲线拟合法.对预对准系统进行了误差分析.最后,采用光学式预对准方法,对12 in硅片进行了预对准实验研究.实验结果表明硅片缺口的重复定位精度小于4.8μm,预对准时间为23 s,满足设计要求.

A system for automated pre-alignment of wafer with a diameter of 12 inches is developed. At first, the architecture of the wafer pre-alignment system is designed according to its task and flow. Next, several detection methods for prealignment are introduced and the least square circle fitting approach is used to position the wafer＇s center. Two methods, i. e. , an edge flexion method to detect the range of wafer notch and an arc fitting method to calculate the notch base point, are proposed. Then, error analysis on the wafer pre-alignment system is presented. Finally, using the optical pre-alignment methods, the experiment with the 12-inch wafer is made. The experimental result shows that the repeatability of the wafer notch is less than 4.8 p,m and the whole pre-alignment process spends 23 seconds, which satisfies the design requirements.