Laser Sintering of Copper Nanoparticles: A Simplified Model for Fluence Estimation and Validation

Copper (Cu) has already replaced aluminum as the primary material for interconnect fabrication due to its superior electrical and thermal conductivity. Low resistivity of Cu decreases the RC delay which in turn increases the integrated circuit (IC) speed. Copper nanoparticle (NP) inks can also serve as a promising replacement of silver NP inks in 2D printing applications on solid and flexible substrates. This paper presents a simplified model to estimate optimum laser sintering parameters of Cu NPs. The model is validated by the experimental sintering results using nanosecond and femtosecond pulsed lasers. The predicted sintering thresholds agree well with sintering experiments.