A study of filling process for UV nanoimprint lithography using a fluid simulation

Nanoimprint lithography has advantages such as good resolution, CD uniformity and LER. However, nanoimprint lithography involves risks. In particular, defectivity is the most critical issue for nanoimprint lithography. Above all, the "non-fill defects" dominate such defects for UV nanoimprint. At the filling process of imprint resist, the capillary force that occurs between an imprint-resist and surface of template plays an important role. Our experience, suggests there is a relationship between the filling characteristics and pattern size of template. We also think the resist properties and the environmental conditions such as atmosphere pressure play important roles in the filling process. This paper explains the filling process dependency on the properties mentioned above. We analyzed the filling process using fluid simulation. At first, we assumed several pattern sizes with the same pattern height. Then, the filling times were estimated for each pattern size with various resist properties and the environmental conditions. An important attribute of our simulation model is the consideration accorded to the dissolution of gas between the template and imprint resist. As a result, the filling time of smaller pattern was found to be shorter than that of larger pattern. The assumed patterns are space and via on template ranging in size from 22nm width to 1000nm-width. The pattern height is 60nm. In this paper, we studied characteristics of filling mechanism by using fluid simulation. The relations between CD and filling time were obtained. We found that the gas dissolution rate is the dominant parameter for filling time.