Inline plasma analysis as tool for process monitoring in laser micro machining for multi-layer materials

Laser micro machining is an innovative manufacturing technology with a wide range of processable materials and a high level of flexibility. Especially for processing multi-layer materials it is a tool for surface structuring and subsequent functionalization. The manufacturing of e.g. conductor paths for solar cells or batteries requires specific ablation depths on multi-layer materials in order to reveal conducting layers as functional conductor paths. To achieve an ablation of a specific, layer an in-line process monitoring can be used to warrant a robust manufacturing preventing damage on further surface layers. With regards on the need of material specific ablation parameters, this paper addresses the development of a measurement system based on laser induced breakdown spectroscopy (LIB S) as a tool for real-time process monitoring by in-line plasma analysis. The presented results show the specific plasma emission variation at layer interfaces, which can be used for real-time feedback process control with the goal of minimizing the ablation of further layers.