Analyzing the process window for laser copper-link processing

Control of laser pulse shape and polarization improves the reliability of laser processing of copper links used for circuit redundancy. Using finite element modeling, simulation shows that fast-rise-time laser pulses give a unique pulse shape that helps avoid lower corner cracking by initiating upper corner cracking and stress relief. Polarization variation enables control of hole size by changing energy coupling into the link, thereby increasing the process window significantly.