Droplet-based photoresist deposition

Photoresist droplets are ejected onto a wafer surface by an acoustic two-dimensional micromachined ejector array. The spread of single droplets on a silicon wafer surface at varying droplet speeds is studied. Series of photoresist droplets are printed periodically drop on demand on a silicon wafer surface and profiles of a single droplet and two droplets overlapping with varying distances of 25 and 1μm on a silicon wafer are demonstrated. Moreover, 3.4μm thick spinless full coverage of a 4in. wafer with photoresist is demonstrated which indicates a potential for coating wafers in less than a few seconds.