Simulation and Experimental Study on Photoresist Flow and Deforming Behavior in Imprint Lithography Process

Abstract

Abstract ：It is necessary to understand and predict the photoresist flow and filling behavior in imprint lithography process to obtain high fidelity replication of the template patterns. The finite element model based on viscosity fluid for resist flow and filling is established considering the properties of the resist adopted in this study and the influences of geometric characteristics of template patterns, initial resist film thickness and micro/nano effect on resist rheologic properties are investigated to distinguish different flow driving mechanisms by tracing the resist moving boundary by using volume of fluid (VOF) method. The calculation results show that the resist filling is accomplished in single or dual peak deformation mode. The mode transition point can be predicted from the ratio of characteristic groove width to initial resist film thickness and the transition point is influenced by the surface/interface effects. The required from pressure is minimized when the aspect ratio of the template patterns is approximately 0.8. The optimal initial resist thickness is about twice of the depth of the patterns on the template considering both the pattern transfer quality and residual resist thickness. The numerical simulations are compared with the related experimental results in imprint lithography and it shows that the calculation results are in good agreement with the experimental results, which indicates that the conclusions from simulation analysis are valid and can be used as the process layout rules for the template pattern geometry, initial resist thickness and template surface treatment.