Study of demolding in nanoimprint lithography with pseudoplastic metal nanoparticle fluids

As a new type of semiconductor processing technology, nanoimprint lithography has attracted growing attention in recent years because of its low cost, high yield, simple process and good fidelity. In order to improve the fidelity of patterning, a novel method, direct metallic pattern nanoimprinting with a pseudoplastic metal nanoparticle fluid as the transfer medium, is proposed and studied. Demolding, which has a great impact on the integrity and fidelity of patterning, is a critical step in nanoimprint lithography. Through the analysis of key parameters, which affect patterning integrity at the initial time of demolding, analytic expressions of the forces acting on the microstructure, e.g., adhesion force, internal force, friction force and other related parameters, as well as the effects of the friction coefficient, the Hamaker constant, the aspect ratios of the patterning, and the size of the metal nanoparticles on the integrity of patterning are obtained and analyzed. In the case of the absence of a bottom fracture in demolding, the analysis results have important guiding significance for the optimization of the parameters set in demolding process.