Investigation of material ejection in laser decal transfer-based µ-3D printing of ZnO ceramics with microsecond pulsed CO2 laser

Abstract

In Laser decal transfer process, the materials are printed in micron-sized dots without changing its phase from thin film coated substrate (donor substrate). The pulsed laser irradiates the donor substrate opposite to the coated side and transfers the material in the same phase to another substrate kept very close to the donor substrate. The process has shown its potential for printing microsensors without any changes in physical and functional properties during the printing process for the electronics components. Generally, ZnO-based patterned structure is still challenging for the existing manufacturing techniques without hampering its functionality in the sensing application. In this work, an attempt has been made to print ZnO structure in solid phase using maskless µ-3D printing using a long-pulsed CO2 laser. A two-dimensional numerical model in COMSOL Multiphysics is developed to estimate the temperature induced by the laser irradiation on the sacrificial layer, and energy conservation is applied to estimate the particle’s velocity. A deformed mesh geometry is used to predict the ablation depth of the sacrificial layer after the laser irradiation. The deformed geometry shows the ablated area in the sacrificial layer, and the temperature induces a different time frame. The ZnO ceramic film is coated on the sacrificial layer followed by the laser µ-3D printing of ZnO on silicon wafer using CO2 laser at three laser fluence, i.e., 530 mJ/cm2, 1030 mJ/cm2, and 1530 mJ/cm2 with 90% pulse overlap. The ejection of ZnO from substrate is visualized using a high-speed camera by shadowgraphy techniques. The ejection mode is defined based on the deviation of the particle from the laser beam direction. © The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature 2024.