Influence of Optical Parameters of Synchrotron Radiation Lithography Beamline on Pattern Replication

The influence of the angular divergence of X-rays incident on an X-ray mask and the exposure spectrum, which are the optical parameters determined by the geometric and band-pass properties of beamline optics and the synchrotron radiation (SR) spectrum, on resist pattern replication on various substrates was investigated. Using a compact storage ring as the SR source, we confirmed that there is no problem in 0.15-µm-feature pattern replication on Si substrate, regardless of the type of beamline optics. However, we found that an undercut or undeveloped portion inevitably occurs on a substrate which is covered with high atomic number material film, but this overexposure of resist can be reduced in a beamline with a broad band exposure spectrum.