More and more electronic applications need conductive paths on different substrates. One approach to apply these structures is by wet-chemical coating processes which have been proven to be a powerful tool for producing functional layers. Printing techniques such as inkjet show great potential due to resource-efficient, flexible and inexpensive application of structures. This is particularly challenging as the necessary thermal treatment of the films often requires temperatures that exceed the temperature stability of the substrate.
By using laser treatment to substitute the oven process Fraunhofer ILT is able to overcome those drawbacks and create silver conductive paths out of nanoparticulate solutions on inexpensive but highly temperature sensitive PET foil. The achievable high heating and cooling rates allow the required film temperatures to be reached without damaging the temperature-sensitive substrate. Drying, sintering and even partial melting of the nanoparticulate layers have been achieved by using laser radiation. Partial melting of the layer increases the conductivity dramatically and can reach conductivity of more than 50% of the bulk material.