Laser-Induced Forward Transfer of Pre-Machined Donor Films

Abstract

Micro-pellets of ZnO with a diameter of 5-10 µm and extremely smooth edges have been printed using laser-induced forward transfer from 1 µm thick films, that had been prepatterned using focussed ion beam (FIB) machining.

Laser-induced forward transfer of pure metals

“…This process requires the use of multiple pulses to achieve solid phase LIFT, much as like it is proposed in previous work [58,59]. The novel technique described in this work, however, is an improvement on either previous approaches.…”

“…At the same time, applications ask for high flexibility regarding the shape of the deposited material. Several approaches have been demonstrated [55][56][57][58][59] in order to address the flexible printing of metals and metal pastes with variable shapes in solid phase. However, none of those approaches solves all the problems mentioned above.…”

“…Furthermore, the required number of pulses to transfer the pellet is known a priori (namely exactly two) and only the required fluence level has to be determined. A clear advantage is the implementation using a single setup, without requiring other equipment such as the focused ion beam used by Kaur et al [59]. This approach gives a real-time flexibility in pellet shape, however pre-machining can of course still be performed by some other donor preparation techniques.…”

“…Ballistic Laser-Assisted Solid Transfer (BLAST), as demonstrated by Banks et al [58], uses the laser out of its focal plane (defocused) to achieve beam shapes with a higher intensity perimeter that directly weakens the shearing areas of the donor layer. A focused ion beam (FIB) technique is employed by Kaur et al [59] to pre-machine the donor layer in the desired pellet shape. The LIFT process is then used to transfer only the pre-machined part of the donor layer.…”

“…Section 9.3 provides a proof-of-concept in the form of successfully transferred solid phase pellets of varying shapes from 100 nm thick gold donor layers. Inspired by BLAST [58] and the LIFT of pre-machined donor layers [59], single-and double-pulse experiments with modulated laser beams according to the desired pellet shapes are presented.…”