Evaluation of rinse material and process for EUV lithography

Extreme ultraviolet lithography (EUVL) is the most promising option for future manufacturing of IC devices at sub-10nm node. However, resist pattern collapse is one concern for high volume manufacturing. To mitigate resist pattern collapse, rinse material is applied for EUVL. However at narrow pitches, it was found that some rinse materials caused pattern bridging and critical dimension (CD) shift. In this study, we suggest a model of resist deformation by surfactant penetration to resist pattern. Moreover, we focused on affinity between resist and surfactant which is main components in rinse material to clarify the pattern bridging and CD-shift issue by inducing surfactant penetration to resist pattern. To define the affinity between each material, Solubility Parameter (SP) value and Difference of Solubility Parameter value (DSP) of each material was calculated. The relation between surfactant penetration and DSP of each material was investigated. To clarify the relation, stress test was applied to enhance pattern deformation. As a result, it can be said that there is good correlation between surfactant penetration and SP value. Using these studies, rinse material design with low affinity surfactant for resist was able to achieve no CD-shift and less pattern bridging defect number.