Improving Conformality in Selective Dip-Coating of Patterned Planar Substrates

The capillarity-driven self-assembly of small chips onto planar carrier substrates heavily relies on the selective deposition of thin fluid films onpatterned binding sites. We found that the addition of a wetting sidewall, surrounding the entire site perimeter, enables the conformal dip-coating ofplanar sites and significantly improves the reproducibility of the coating process. We demonstrated the feasibility of this method with the dip-coating of square sites featuring methyl- and fluorine-based surface chemistries. Both experimental and simulative evidence of the advantages of the wetting boundary on film coating accuracy are presented.