Sintering of printed nanoparticle structures using laser treatment

Printed intelligence is a promising new technology to produce low-cost electronics. Non-conductive circuits can be printed using nanoscale metal particle inks. Due to the nanoscale size of the particles, the typical sintering temperatures of 100-300 °C are only a fraction of the macroscopic melting point of the corresponding materials, thus allowing the use of paper or plastic substrates. Sintering of printed nanoparticle structures using laser treatment has been investigated at VTT. Laser sintering can be utilized in manufacturing of printed conductor structures such as antennas, circuits and sensors. A drop-on demand printer was used to print patterns with metallo-organic silver nanoparticles on a flexible polyimide substrate. Laser sintering was made with a 940 nm CW fiber coupled diode laser. Process was optimized using different laser power levels, line separation and repetition rounds. Conductivity of laser sintered samples was compared to conductivity of samples sintered in convection oven.