Femtosecond laser induced forward transfer of materials

The Laser Induced Forward Transfer (LIFT) process uses a laser pulse to selectively remove thin film material from a transparent donor substrate and transfer it in the form of micron-sized dots onto an acceptor substrate nearby. This microprinting process can be used for various applications such as rapid prototyping of microelectronic circuits for research applications and for MEMS repair. In the present paper we report a scaling study of the size of LIFT of gold dots as a function of laser energies from 45 nJ to 100 μJ. All LIFT experiments are carried out using an 800 nm Ti:sapphire laser system emitting pulses of 110 fs duration. The laser beam is focused to spot sizes of a few microns onto the donor substrate using a 10X microscope objective. 2 μm to 15 μm diameter gold dots showing continuous morphology were transferred in our experiments using laser energies from 100 nJ to 5 μJ. For higher energies the transferred dots show ring-like morphology.