Part tilting in capillary-based self-assembly: Modeling and correction methods

Abstract

We present a model and experimental results on tilt angle of microparts in capillary-driven self-assembly. The assembly is carried out in an aqueous environment, using a heat curable adhesive for part-substrate lubrication and mechanical bonding. Silicon parts and substrate have matching hydrophobic binding sites, which drive the assembly by surface energy minimization. Force balance analysis of an assembled part leads to a model describing the dependence of tilt angle on assembly parameters such as adhesive volume and water-adhesive interfacial tension. The effect of adhesive volume on tilt angle is investigated experimentally. Tilt correction of the assembled parts is achieved by providing external energy to the system via vertical vibration.