Consideration on segregation behavior of the surface localization material and the pattern roughness degradation in EUV lithography

Extreme ultraviolet (EUV) lithography using light of 13.5nm wavelength is essential for high-resolution integrated circuits. However, the various defects that occur during the development process are challenges that must be continuously addressed. Much effort has been made to solve these challenges. Photoresist (PR) point of view, one of the common methods is using a Surface Localization Material (SLM). The SLM can promote development of photoresist film surface at unexposed area during the development process. This can help wash away defects from the photoresist surface, but it is also well known that a surface localization material can worsen the roughness of the pattern at EUV technology. Accordingly, in this paper, we traced the distribution of the surface localization material in EUV PR film through Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and analyzed change in dissolution rate of photoresist and suggested a hypothesis. In addition, the roughness changes of hole pattern were confirmed by EUV tools.