Fabrication of Patterned Surface Reactivity Templates Using Physisorption of Reactive Species in Solvent-imprinted Nanocavities

摘要

A critical requirement for using thin polymer films in many microelectronics applications is the ability to selectively immobilize materials on patterned polymer templates. Selective surface functionalization using covalent solution-phase chemistries is the most direct approach, but suffers several drawbacks, including (1) reduced reaction rates or yields on a surface compared to solution environments; (2) surface template distortion due to reagent/polymer incompatibilities; and (3) concerns arising from the use of hazardous or expensive materials. We describe here an alternative noncovalent patterning approach based on selective trapping of ligands in solvent-imprinted nanocavities on aromatic polymer film surfaces. Noncovalent binding is based upon exclusion of a ligand from aqueous solution into hydrophobic cavities within the polymer film. Spatial control of the binding is accomplished either by: (1) increasing local hydrophilicity sufficiently to suppress ligand binding (masked DUV, STM, proximity x-ray), (2) selective placement of the ligand on the film (microcon-tact printing), or (3) selective removal of pre-loaded ligand from the film (25 kV or 50 kV e-beam). Retained reactivity of the adsorbed ligands is illustrated by fabrication of metal or fluorescent patterns on treated polymer surfaces. The fabrication of features in metal films with resolutions to～40 nm is demonstrated.