Maskless Lithography Using Drop-On-Demand Inkjet Printing Method

Writing process patterns directly on a substrate with small liquid droplets generated by Drop-On-Demand (DOD) inkjet devices offers a low cost, non-contact, low temperature, flexible, and data driven patterning approach. Existing inkjet printheads have a limited number of inkjet devices, which generate droplets on the scale of tens of microns. In our research, we have developed a monolithic inkjet printhead for maskless lithography based on silicon micro-machining technology. This printhead is composed of a large array of thermal bubble inkjet devices fabricated on a single silicon wafer. A high-resolution video imaging system has recorded stable generation of water droplets down to 3.5μm. Au patterns as small as 8μm have been formed on silicon substrates by printing with suspensions of Au nano-particles. Smaller droplet dimensions extending to the nano-scale is supported by theoretical analysis. This printhead technology can form the basis of a maskless lithography system with moderate throughput for building micro and nano-scale electronic circuits and MEMS devices.