Polymer peel-off mask for high-resolution surface derivatization, neuron placement and guidance

We present a dry lift-off method using a chemically resistant spin-on plastic, polyimide, to pattern surfaces with high accuracy and resolution. Using well-known lithographic and reactive ion etching techniques, the spin-on polymer is patterned over a silicon dioxide surface. The plastic efficiently adheres to the silicon dioxide surface during the chemical modification and is readily lifted-off following the derivatization process, permitting highly reliable surface derivatization. The verticality of the reactive ion etch enables sub-micrometer features to be patterned, down to 0.8 µm. The technique is used to pattern neurons on silicon dioxide surfaces: efficient neuron placement over a 4 mm area is shown for patterns larger than 50 µm while process guidance is shown for 10 µm patterns.