Thermo-mechanical modeling of laser-driven non-contact transfer printing: two-dimensional analysis

Abstract

Transfer printing is an emerging technique for materials assembly and micro-/nano-fabrication. An important emerging variant of this process involves laser-induced impulsive heating to initiate separation at the interface between a soft, elastomeric stamp and hard micro-/nano-materials (i.e. inks) on its surface, due to a large mismatch in coefficients of thermal expansion. The result is the active ejection of the inks from the stamp to a spatially separated receiving substrate, thereby representing the printing step. In the following, a thermo-mechanical model is established to analytically obtain the temperature field, and the energy release rate for delamination at the interface between the stamp and ink in the form of a rigid plate. The normalized critical laser pulse time for interfacial delamination depends only on the normalized total heat flux at the interface and the normalized width of the ink structure. This scaling law has been verified by experiments and the finite element method.