High Resolution Drop-on-Demand Based Electrohydrodynamic Printing of Conductive Silver Micro Patterns
Inkjet and Electro hydrodynamic (EHD) printing based methods have been used to print conductive micro patterns for device fabrication but the limit of pattern width achieved is usually up to 10 µm. Single pulse drop on demand (DOD) based methods have been applied to print patterns with better resolution. These printing methods offer printing of fine micro-scale patterns through additive manufacturing approach that has several advantages over lithography and conventional MEMS device fabrication techniques. One of the major advantages is the ability to print on already fabricated devices and systems for alteration and repair purposes, but; printing micro patterns on a MEMS device is a tough task due to the disturbance in the cone jet and the formation of satellite droplets. In this study, a modified multi-pulse DOD technique has been employed for higher accuracy to print fine silver micro-patterns on a MEMS device. Parameters like supply voltage, waveform shape, frequency, pneumatic pressure, and ink flow rate have been studied and optimized to achieve repeatable and stable conductive patterns up to 3 µm. The modified EHD DOD system eliminates the static charges problem and enables printing of highly repeatable sub-10 µm conductive patterns for MEMS repair.
Keywords – Electro hydrodynamic printing, high resolution, Drop-on-demand (DOD), micro-patterns, MEMS repair.