自动投影光刻中的暗场对准技术

A dard field alignment technique in the stepper

暗场对准技术是利用光学暗场成像原理和微光真空光电探测技术，使投影光刻硅片上的标记获得大幅值、高信噪比的对准信号通过双池偏差优化软件，借助计算机进行采样控制和数据处理，从而获得很高的对准精度。对多种不同工艺硅片上的标记进行对准试验，精度达０．２μｍ（３σ）。该技术精度高，对硅片光刻工艺的适应性广，可用于大规模集成电路生产硅片光刻时的实际对准工作，使我国的投影光刻技术进入１μｍ特性线宽的实用阶段。

A dark field alignment system using optical dark field technique and reflecting the dark field wafer information toward the photomultipler tube is presented. The alignment signal with high contrast and ratio of signal to noise can be obtained from the mark on the wafer. The dark field alignment system has been designed and assembled. A bicell detector implemented in software is used for calculating the misalignment value.The experiments with various wafers show that the alignment accuracy of this system is within 0. 2 μm (3σ). The technique is suitable for the direct stepper on the wafer (DSW) which is used for manufacturing microcircuits.