Hybrid structural electronics fabrication by combined SLA and metal printing

A method is described where 3D electronic devices are fabricated using a hybrid printing approach which combines several steps: Top illumination stereolithography; laser induced forward transfer (LIFT) printing of conductive materials; placement of active and passive components and their electrical interconnection by a non-contact, metal LIFT process. By applying this approach, free-form 3D functional electronic structures could be manufactured by a single hybrid tool. The adhesion of LIFT printed metal droplets onto various organic substrates of interest for device fabrication was investigated. The results suggest two possible approaches for improved adhesion by either printing at elevated surface temperature or surface roughening by laser pre-treatment. The resulting track resistivities were found to be in the range of ×5-10 higher than bulk copper resistivity. We present several exemplary printed devices with different complexities and functionalities as demonstrators of the proposed hybrid technology.