Structural Design And Signal Processing Of3D Zero Sensor Of Wafer Stage Of Lithography

Semiconductor industry plays an increasingly prominent role in economic, theperformance of lithography affects the yield of the chip directly.In recent years,dualstage technology has been applied which makes the yield of chip improved sharply,thedevelopment process of dual stage requires masses of simulation.Research of this paperis based on the step-scan-projection lithography machine.3D information of the waferstage is measured by laser interferometer optical sensors. But laser interferometer is anincremental sensor. Zero calibration is a necessary for it.This paper will design a3Dsensor for the zero calibration. After signal processing, zero information is passed to thesignal collection board. And then correct the zero compensation value of laserinterferometer.Firstly, this article briefly describes several of the most commonly used methodsfor measuring the micro-displacement. According to the characteristics of every method,we decide to use the optical triangulation method as the displacement measurement.Then analyzed the basic working principle of position-sensitive detector and pyramidalprism. And described the3D measurement methods by position sensitive detector withpyramidal prism.Secondly, described the design and the implementation of two-degrees-of-freedommeasurement system from the optical, mechanical, hardware circuit, based on ofmicro-displacement measurement principle by position sensitive detector, includingoptical system analysis, selection of key components, mechanical structural analysis,hardware circuit design and software programming.Thirdly, analyze the error may exist in measurement system which is designed bythis article. And then design the corresponding experimental program to evaluate thesystem performance. According to the results of the experiment, test the resolution andrepeatability of the measurement system.Finally, studied zero calibration problem of the laser interferometer system。Based on the the zero position sensor designed by this article, propose a calibration methodand establish relevant models. Identify zero calibration process for the laserinterferometer.