Application of a pulse programmable fiber laser to a broad range of micro-processing applications

Spatial beam shaping has long been utilized to improve laser processes and has often generated spectacular improvements in the end results. Until recently the temporal shape of laser pulses has been limited by the design parameters of the laser cavities and shaping in the temporal domain has remained relatively unexplored. The advent of the MOPA fiber laser has opened the door to creating arbitrary temporal waveforms with shape, energy, and duration being entirely independent from the laser repetition rate and changeable “on the fly.” This new degree of freedom in the laser processing parameter space has not only enabled new and improved laser processes but provided a new tool to study the dynamics of the laser material interaction itself which can greatly speed process development. Furthermore having this flexibility allows a single laser to cover a range of process parameters that heretofore normally required using several separate laser systems. This flexibility has proven to be especially useful in the processing of materials for Photo-Voltaic (PV) applications. In this work we report on the application of temporal pulse shaping to CIGS P2 & P3 processing, CIGS P1 processing (molybdenum on glass), a-Silicon P1 processing (ZnO on glass), c-Silicon via hole drilling for emitter wrap through (EWT) and other processes using the PyroFlex 25 pulse programmable fiber laser. The temporal pulse shaping feature of the laser is demonstrated as a tool to probe the process dynamics and speed the determination of optimal process parameters. When applicable, results between the pulse shape of a traditional laser and an optimized laser pulse shapes are compared.