The challenges of highly sensitive EUV photoresists

Abstract

A prerequisite for good photoresists is high sensitivity, but unfortunately highly sensitive resists are usually accompanied by line roughness. Even if understanding what is causing roughness in resists were not completely in its infancy, we still have not achieved complete answers and effective solutions to these issues. Our group has been working with Zr-based and Hf-based resists almost one decade now and has shown that these resists have incredibly high sensitivity. At the same time, we have shown that these resists after development possess scumming issues and increased roughness. And while we have managed to deal with these scumming issues by employing a variety of strategies, we did not succeed in improving roughness; we have changed our processing method and decreased our size distribution to get a material with more well-defined structure compared to the starting material, but roughness remains. What we are investigating now, is whether a well-defined Zr-monocrystal cluster could be the answer to our problem.