Selective Metallization on Ordinary Polymer Substrates by Laser Direct Activation of Copper Phosphate or Nickel Phosphate

In recent years, selective metallization on polymer surfaces has attracted considerable attention due to its excellent properties and wide applications. This paper reports that copper phosphate (Cu3(PO4)2) or nickel phosphate (Ni3(PO4)2) was selected as laser-active material to successfully fabricate metallic patterns on ordinary polymer substrates by laser direct activation and electroless plating. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were utilized to characterize the interaction mechanism between a nanosecond-pulsed laser (355 and 1064 nm wavelengths) and Cu3(PO4)2 or Ni3(PO4)2. It was found that after 355 or 1064 nm laser activation with appropriate parameters, Cu+ was generated from Cu3(PO4)2, and NiO was generated from Ni3(PO4)2. At the same time, Cu+ or NiO adsorbed on the porous sponge-like microstructure of modified polycarbonate (PC), respectively, and acted as catalytic active centers to realize selective copper deposition in the laser-activated zone. Furthermore, the obtained copper layers were confirmed to possess good selectivity, electrical conductivity, and high adhesion strength (the highest grade of 5B). Moreover, from comparisons of Cu3(PO4)2 with Ni3(PO4)2 and of 355 nm laser activation with 1064 nm laser activation, the 1064 nm laser activation of Cu3(PO4)2 produced the most catalytic seeds (Cu+) and had the best catalytic effect.