Fast Organic Conditioning of Patterned Surfaces for Capillary Part-to-Substrate Self-Assembly

Abstract

Selective chemical preconditioning of geometrically patterned substrates and parts is necessary to enable capillary part-to-substrate self-assembly. On the other hand, long preparation procedures may preclude the throughput enhancement potentially brought by the technique. In this paper, we investigate the fast chemical preconditioning of patterned substrates by the chemisorption of thiolates from the liquid phase. We found that even under conservative conditions, deposition times as short as 15 s (i.e., about two orders of magnitude shorter than previously reported in specific literature) are sufficient for the intended purpose, which is changing the wetting character of metallic binding sites enough to allow their selective dip-coating with hydrophobic fluid lenses. Moreover, perfect fluid coating conformality is achieved when such short deposition times are combined with the use of recessed binding sites. Our findings further confirm organic species to be remarkable tools for the chemical preconditioning of patterned surfaces as they may help actualize the full benefits of capillary self-assembly for electronic packaging.