Relation between optical property of pattern image and adhesion of resist pattern

Abstract

To get fine patterns of ArF photoresist without pattern collapse, we studied the relation between optical property of pattern image and adhesion of photoresist pattern. In concern of the type of photo mask, we found that using attenuated phase shift mask could make experimental small resolution limit beyond the estimation by simulation. About ARC substrate structure (inorganic ARL/ oxide/ polySi), it was important not only to optimize the reflectivity, but also to optimize the phase of reflectance. Photoresist was easy to collapse when the phase of reflectance at the interface between photoresist and inorganic ARL is near the 0 degree, although the reflectivity was set below 1%. In order to change the phase of reflectance, the film thickness of oxide was varied. In the observation of photoresist profile, bottom profile was changed similar to simulation. In the case of organic bottom ARC, we could not observe the effect of the phase.