Effects of laser induced plasma/plume on UV laser ablation

We have developed a technique using an intensified CCD camera to study the behavior of the plasma/plume during a single laser pulse for the purpose of laser process optimization. Several experiments were designed to study and measure parameters such as the attenuation of the incoming laser pulse by the laser-induced plasma/plume along the laser beam path. Also studied were the attenuation versus laser fluence, the attenuation versus time and versus the number of laser pulses used at one location of the work sample (or in another words, the depth of the laser-drilled via). The effect of the environment (different gas fills/flows) on the plasma/plume behavior is another topic. This paper presents the current results of these studies