EFFECT OF ELECTRON-BEAM ORBIT DISTORTION ON OPTICAL-PERFORMANCE OF THE SYNCHROTRON-RADIATION LITHOGRAPHY BEAMLINE

We have investigated the effect of the synchrotron radiation (SR) sour ce drifts, namely, the source position and emission angle, caused by e lectron beam closed orbit distortion (GOD) on optical performance of t he beamline such as the exposure field size, the illumination intensit y and the uniformity. We theoretically derived that SR source drifts s hould be controlled within +/-0.4 mm and +/-0.2 mrad for the position and emission angle drifts, respectively, to obtain uniformity better t han 15% for our beamline. We also propose a new technique to directly measure the SR source drifts using the focusing property of the mirror and the SR beam monitor installed in the beamline, which can be appli ed to predict the changes of optical performance of the beamline, and to monitor the electron beam drifts for correcting COD.