Contrast enhancement behavior of hydrogen silsesquioxane in a salty developer

Abstract

The authors investigated a contrast enhancement behavior of hydrogen silsesquioxane (HSQ) in a salty development system (NaOH/NaCl). Time-resolved analysis of contrast curves and line-grating patterns were carried out to investigate the unique properties of a salty development process. In NaOH developer without salt, the development process was saturated beyond a certain development time. On the other hand, the addition of salt enabled a continuous development, which was not observed in the pure NaOH development. The continuous thinning process enhances the contrast of HSQ in the salty developer, which allows a fast collapsing behavior in HSQ line-grating patterns. During development process, salt seems to have the role of modifying HSQ by breaking network bonds preferentially, leading to a continuous development rate.