Compatible Ag⁺ Complex-Assisted Ultrafine Copper Pattern Deposition on Poly(ethylene terephtalate) Film with Micro Inkjet Printing

Firm immobilization of catalysts on the predesigned position over substrates is an essential process for producing flexible circuits by the electroless deposition (ELD) process. In this work, a compatible Ag+ complex was developed and directly printed on the poly(ethylene terephtalate) (PET) film through a micro inkjet printing instrument to trigger the deposition of ultrafine copper patterns with approximately 20 μm in width. Morphological and elementary characterization verified that the nanosized silver catalyst was uniformly distributed in the bridge layer, which could enhance the adhesion between the PET film and deposited copper patterns. Moreover, after 30 min of ELD, the copper patterns exhibited a low resistivity of 2.68 × 10–6 Ω·cm and maintained considerable conductivity even after 2000 times of cyclical bending. These interesting conductive and mechanical features demonstrate the tremendous potential of this Ag+ complex-assisted copper deposition in the interconnection of high-density integrated flexible electronics.