Laser Direct Activation of Polyimide for Selective Electroless Plating of Flexible Conductive Patterns

Flexible conductive patterns on polyimide substrates are attracting increasing research interest in the areas of wearables, biomedicals, automotives, and energy harvesters. This paper reports a laser-induced selective activation (LISA) process for electroless metallization and, therefore, the creation of complex conductive patterns on polyimide substrates. In this process, a Q-switched pulsed laser is utilized for scanning the surface and forming the catalytic layer consisting of microporous structures, which enhances the stability of electroless plated metallic structures on the polyimide surface and exhibits superior mechanical stability under repeated bending and harsh environments. The high resolution of the metallic patterning enables the demonstration of a copper microgrid pattern with a line width down to 50 μm. Moreover, flexible light-emitting diode displays and electromagnetic interference shielding films are successfully manufactured to indicate the promising capability of our LISA process.