In-situ monitoring of cavity filling in nanoimprint by capacitance

During nanoimprint, the uniformity and precision of the imprinted nanoscale structure and components are affected when the mold filling becomes irregular. To overcome the shortcomings of the current monitoring approach, an attempt has been made in this research based on the concept synthesized in the approved and pending patents presented in H, Hocheng and C.C. Nien (2004), and C.C. Nie et al. (2004), namely the capacitance measurement technique for a nanoimprint process. Such a capacitance measurement technique was used to detect the continuous variations of capacitance of the parallel-plate capacitor formed by the top plate electrode made on the imprint mold and the ground plate electrode on the polymer substrate during the course of imprinting. To evaluate the feasibility of the proposed technique of parallel-plate capacitor, both numerical modeling of parallel-plate capacitor and experimental investigation have been performed. The state variation of mold filling has significant effect on the value of capacitance, which indicates the parallel-plate capacitor is a feasible tool for real-time in-situ monitoring for a nanoimprint process.