Laser Induced Forward Transfer (LIFT) is a key enabling technology for large area processing of printed electronics, capable of printing a wide range of materials rapidly and digitally. A major barrier for large scale implementation and adoption of the technology is the current achievable printing resolution, commonly reliably limited to the tens of micron. In LIFT, a donor substrate ink carrier is locally irradiated by a short pulse laser causing the transfer of material from the donor layer to a receiving substrate. The donor layer and laser processing are keys for precision patterning. The SIMLIFT project looked at optimising various parameters associated with the LIFT process to overcome current limits and achieve high resolution fine features.
SIMLIFT aimed to analyse:
- the effect of varying thin film donor deposition processes (namely spin coating, blade coating, forward roll coating) on the donor film morphology and resulting transfer;
- the effect of varying the laser pulse duration that dictates the physical ejection mechanism (namely from nanosecond, picosecond, to femtosecond level duration pulsed lasers).
- the accuracy of laser processing through the novel integration of new microlens arrays for affordable accurate digital patterning.
- The project assessed different thin film deposition methods (spin coating, blade coating, roll coating) analysing uniformity, associated ink rheology and optical transmission.
- This allowed the definition of the most suitable conditions toward SIMLIFT in terms of quality and compatibility with industrial LAE manufacture.
- A nanosecond DPSS laser was used to asses the effect of D-A gap, speed, power and donor thickness on donor deposition.
- Using these insights, the team were able to produce fine lines with an average width of 12 microns.