Optimizing microfluidic ink delivery for dip pen nanolithography

This work demonstrates the design optimization, fabrication process development, process optimization and testing of a microfluidic ink delivery apparatus (called "Inkwells") for simultaneously coating an array of DPN(TM) pens with different inks. The objective of this work is to deliver between 4 and 10 different inks from reservoirs into appropriately spaced microwell array. A tips of the multi-pen array are coated with different inks by dipping them into the microwell array. The reservoirs, microwells and their connecting micro-channels were etched in silicon wafers using Deep Reactive Ion Etching (DRIE). Fluid actuation was achieved by capillary wicking. The optimum layouts for different applications were selected with respect to the volume requirement of inks, the efficacy of ink-well filling, to obviate the problem of bubble formation, and to test the operations of dipping and writing with a parallel array of pens.