Fabrication and Characterization of Fluidic Channel and Dispensing Nozzle Integrated Microcantilever Heaters

In this paper, microchannel and dispensing nozzle integrated microcantilever heaters are proposed as a new platform enabling drop-on-demand bubble jet printing with fast and efficient heating and real-time printing process monitoring for the first time. Microcantilever heaters with integrated microchannel and dispensing nozzle are batch fabricated via ion implantation and polysilicon sacrificial process. Then, local temperature of fabricated microcantilever heaters are calibrated with micro Raman thermometry. Temperature calibrated microcantilever heaters are characterized under various pulsed heating powers sufficient for bubble generation and bubble jet microdroplet dispensing with a reference printing solution. Upon pulsed heating, heating thermal time constants are extracted from both electrothermal and electrothermomechanical responses, each of which are analyzed with temperature-dependent electrical resistance and resonance frequency, respectively. Besides the fast and efficient heating capability, our proposed system can down modulate viscosity of non-Newtonian ink solutions via high-frequency shearing at various eigenmodes and monitor the size and position of thermally induced micro-/nano bubbles within the microchannel via multiple eigenmodes measurements. These promising aspects will accelerate on-demand thermal bubble jet printing towards high-resolution printed electronics.