Nanoparticle selective laser sintering for large area flexible electronics fabrication with a scanning mirror

The development of electric circuit fabrication on heat and chemically sensitive polymer substrates has attracted significant interest as a pathway to low-cost or large-area electronics. We demonstrated the large area, direct patterning of microelectronic structures by selective laser sintering of nanoparticles without using any conventional, very expensive vacuum or photoresist deposition steps. Surface monolayer protected gold nanoparticles suspended in organic solvent was spin coated on a glass or polymer substrate. Then low power continuous wave Ar-ion laser was irradiated as a local heat source to induce selective laser sintering of nanoparticles by a scanning mirror system. Metal nanoparticle possessed low melting temperature (<150°C) due to thermodynamic size effect, and high laser absorption due to surface plasmon mode. These make metal nanoparticles ideal for the low temperature, low laser energy selective laser processing, and further applicable for electronics fabrication on a heat sensitive polymer substrate. We extended our laser selective sintering of nanoparticles research to a large area (> 4" wafer) using scanning mirror to demonstrate current technology for industry level fabrication.