Abstract
An optical autofocus system for a DUV KrF excimer laser wafer stepper was developed by using the PSD (Position Sensitive Detector) as the position sensor. The laser beam was incident on the surface of wafer and the reflected beam was magnified optically by a lens. And the beam was directed onto the surface of PSD by a mirror system. The spatial resolution of the autofocus system was found to be $0.03{\mu}m$.
PSD(Position Sensitive Detector)를 위치센서로 사용하여 광학적 자동촛점 장치를 구성하여 그 특성을 조사하였다. 본 연구는 광 리소그라피 장비인 KrF 엑사이머 레이저 스템퍼를 모델로 개발 하였다. 광원으로 780nm인 반도체 레이저를 사용하였으며, 시준기, 반사경, 렌즈 등을 사용한 광학계를 구성하여 위치신호(position error signal)를 측정 하였으며, 분해능은 $0.03{\mu}m$이었다.