摘要
对投影光刻机同轴对准系统进行了理论分析，阐述了系统的成象机理和工作过程，并在整机上检测了同轴对准系统的重复精度。该系统在掩模和硅片上均刻有对准光栅标记，经光栅衍射后形成干涉信号，使对准信噪比大大提高，并实现了掩模和硅片之间的直接对准，同时利用光弹性调制器组件对光学信号进行了光学调制，由电路实施解调，提供了一种保持高信噪比，又使弱信号探测不降低精度的对准方案。该系统可适用于各种硅片衬底，工艺适应能力强，稳定性能好，重复对准精度可达±０．１μｍ（３σ）。
The coaxial alignment system of the wafer stepper is analyzed in theory.The imaging mechanism and the operating process are described,the repeated accuracy of the coaxial alignment system is tested on the whole machine.The alignment grating marks are etched on mask and wafer,interference signal is formed through grating diffraction,thus the alignment signalnoiseratio is highly raised.The direct alignment between mask and wafer is realized.Optical signal is modulated by means of optical elastic modulator module,then it is demodulated by circuits,thus an alignment method which not only maintains a high signalnoiseratio but also not reduce detection accuracy for the weak signal is provided.The system is suitable for various wafer substrate.Its technological adaptability is strong and stability is good,its repeated alignment accuracy is as high as ±0.1μm(3σ).
出处
《光电工程》
CAS
CSCD
1998年第3期1-6,共6页
Opto-Electronic Engineering
基金
国家"八五"科技攻关项目
关键词
分步重复光刻机
掩模对准系统
对准精度
光刻
Stepandrepeat photoetching machines,Mask aligners,Alignment accuracy.Classification number TN305
