Laser-assisted activation of dielectrics for electroless metal plating

O3, SiC, diamond, ZrO2, etc. are presented. The activation of the dielectric surface can be achieved in a wide range of laser wavelengths and is stable in time. This activation allows selective deposition of various metals (Cu, Ni, Pt, Pd, etc.) with lateral dimensions of several μm. The model of the activation process is discussed. This deals with the modification of the band gap of the dielectric, which involves the appearance of a non-zero density of electronic states in the vicinity of the potential of electroless metal reduction. These electronic states can arise either from the formation of point defects in the ablated surface (for example, F centers in Al2O3, CeO2, or ZrO2) or from the band bending of the dielectric caused by residual mechanical stresses left in the material after laser ablation (SiC or diamond). The data on the activation of dielectrics by mechanical indentation are qualitatively consistent with the model.