Depth-prediction method for direct laser-scribing processes

Abstract

Many semiconductor technologies require the patterning of films to create features not easily achieved during growth or deposition. In the case of transparent conductive oxides (TCOs), this is typically realized through direct laser-scribing. Although there are models conceived to predict the depth of a scribe, the necessary parameters to obtain a given depth are usually found by trial and error. This is mostly due to the models usually being highly elaborated and dependent on difficult to measure variables.

In this paper we introduce a method for predicting the ablation depth in direct laser-scribing processes based on laser-processing parameters and convenient properties like the ablation threshold fluence and the laser penetration depth. In order to apply this method though, the materials must comply with two conditions: a) the material does not develop incubation with successive pulses and b) the ablation depth obtained at any position by a single pulse is determined by the fluence reaching that point. We present experimental data using nanosecond sources and a wavelength of 355 nm for TCOs Indium doped Tin Oxide and Aluminum doped Zinc Oxide that endorse the proposed method as a tool for predicting the ablated depth in laser scribes.