High-precision fabrication of Pd film by laser rear-side ablation with thick sacrificial layer

Thermal damage can be a major problem in laser machining thin films. This paper proposes a laser rear-side ablation technique that incorporates a sacrificial layer to absorb excess energy, thereby lessening the level of thermal damage created in the laser processing of metallic films. The sacrificial layer is placed between the quartz substrate and the metallic film. Experiments were performed on the laser machining of holes in a palladium film using phenol formaldehyde resin as the sacrificial layer in which the pulse energy and sacrificial layer thickness were varied. The experimental results validate the proposed approach in that the judicious choice of the values of the pulse energy and the thickness of the sacrificial layer lead to the creation of high-quality holes that do not display the effects of thermal damage. Thus, the proposed technique can be considered to be a promising method for the laser machining of metal films.