Printability conditions for an all-solid-state laser transfer

Abstract

Several laser technologies exist capable of adding solid materials to a targeted area of a substrate, including photopolymerization, laser sintering, or laser-induced forward transfer. However, the added material normally undergoes a phase change, causing adverse effects such as shrinkage, stress, or degradation. As recently demonstrated, this issue can be addressed by using laser pulses to mechanically delaminate and eject a disk from a solid film. In this case, the laser plays the role of a catapult, with minimal thermal damage to the transferred disk. Despite proven success in micro-electronics and micro-optics, little is known about the mechanical properties of the film that lead to a crack-free all-solid-state transfer. Here, we present a theoretical and experimental study on the effects that film rigidity, elasticity, and plasticity play on laser catapulting. By combining the thermodynamic equations of the laser-generated propulsion force with the theory of thin plate bending, we derived an analytical model that fully describes the list of events responsible for disk ejection. The model is in good agreement with experiments using elastomers, polymers, and metals. A complete printability map based on the film mechanical parameters is reported, which can help to broaden the family of materials suitable for laser additive manufacturing.