Evaluation and optimisation of the SSAIL method for laser-assisted selective electroless copper deposition on dielectrics

Abstract Formation of electrical circuit traces on 3D shaped dielectrics is one of the biggest challenges in 3D Microscopic Integrated Devices (3D-MID). We have developed a new method called “Selective Surface Activation Induced by a Laser” (SSAIL), which is a promising technology for solving emerged production issues for electrical conductors on polymers. SSAIL contains 3 main steps: laser modification of the dielectric surface, chemical activation of the modified areas and electroless plating of the activated parts. In this paper, the route and results on optimisation of the SSAIL process by evaluating properties of the final metal-plated traces are provided. A special validation method of the technology based on the quality and reliability of the plating has been proposed. The sheet resistance, adhesion strength to the substrate and spatial selectivity of plated copper were used to find the optimal laser processing parameters.