Fine-resolution patterning of copper nanoparticles through electrohydrodynamic jet printing

This paper presents the low-cost, fine-resolution printing of conductive copper patterns on silicon substrate. The colloidal solution containing copper nanoparticles is deposited through electrohydrodynamic printing technology. Conductive copper tracks of different width are printed by varying the operating conditions (applied voltage and flow rate) and controlling the jet diameter. The minimum pattern width achieved was approximately 12 µm with the average thickness of 82 nm across the width after the sintering process. The achieved pattern width is five times smaller than the capillary used for patterning. The morphology and purity of the printed copper tracks were analyzed through scanning electron microscopy (SEM), atomic force microscopy (AFM) and x-ray diffraction (XRD). The current-voltage (I-V) characteristic of the printed copper tracks showed linear Ohmic behavior and exhibited resistivity ranging from 5.98 × 10−8 Ω m−1 to 2.42 × 10−7 Ω m−1.