Laser Sintering of Various Film Compositions Used in Flexible Printed Electronics

Producing flexible printed electronics involves depositing metal nanoparticle ink onto a substrate by microdispensing techniques including, but not limited to, aerosol jet, plasma jet, nScrypt, and inkjet printing. The deposited metal ink must be treated through sintering to evaporate solvents and coalesce the nanoparticles to form a conductive circuit. Laser sintering is a promising post-processing method for flexible printed electronic production. To laser sinter, an incident laser beam is directly exposed to the printed film's surface to heat the ink and sinter the particles. The laser sintering parameters vary with the ink, substrate, and film thickness. In our work, we present our study of using three different laser systems for laser sintering using two different substrates. We use nScrypt-printed silver, aerosol jet-printed gold, platinum, and titanium dioxide on rigid glass and flexible polyimide substrates. The laser systems investigated include continuous wave 808nm, 445nm, and 1064nm lasers. We present a thermal model for our setup to better understand and optimize the laser sintering parameters.