Investigations of x-ray exposure using plane scanning mirrors

Abstract

One of the essential processing problems in x-ray lithography using synchrotron radiation is the relatively small vertical divergence of the radiation. A possible method to enlarge the small exposure field is the application of scanning x-ray mirrors in the grazing incidence region with a reflectivity of about 90% at wavelengths around 10 Å. The theoretical values of the absorbed energy in the x-ray resist as a function of the glancing angle, in the case of a plane mirror, have been compared with experimental results. In order to obtain a homogeneous exposure when scanning the mirror, the velocity profile of the mirror movement has to be adjusted to the change in the reflectivity. Another important aspect in the application of the mirror is the degradation of its surface, due to cracked hydrocarbon products under the influence of synchrotron radiation. Initial experimental results show that this problem is not as severe as previously expected. The investigations show that the application of x-ray mirrors is in fact a useful way to enlarge the exposable area in the case of synchrotron radiation, since the loss in intensity is acceptable and the mirror lifetime is satisfactory.