Laser-induced microscale copper trace deposition on glass and PET substrates

• Direct correlation of increasing laser fluence and metal trace width on PET and glass substrates. • Fine copper lines on transparent PET for flexible electronics. • Microscale traces on glass for advanced semiconductor packaging. In today’s electronic applications, creating accurate conductive traces on flexible transparent polymers or glass for improved functionality is crucial. These microtraces serve as integral components for transparent electrodes, heating films, and arrays of responsive sensors. Microscale circuit interposers fabricated on glass substrates are essential to advanced electronics packaging and integration. Micro and submicron scale traces fabricated straight on glass can make breakthroughs in packaging technologies. In this study, we demonstrate the capabilities of Selective Surface Activation Induced by Laser (SSAIL) technology for forming micron traces on transparent materials: glass and polyethylene terephthalate film. Trace width dependency on laser processing parameters: pulse duration, pulse pitch, pulse repetition rate, laser fluence and beam polarization are investigated. Ultrashort laser beam focused with microscopic objective is used for surface activation for selective copper electroless plating. The width of trace formed on glass can be 1.5 µm and simultaneously demonstrate supreme adhesion to the substrate.