Analysis of laser metal cut energy process window and improvement of Cu link process by unique fast rise time laser pulse

In this work, we show that the stress-relief effect caused by breakthrough of passivation by upper cracks as well as the mechanism of the laser cutting process by using finite element modeling. With this understanding of stress-relief effect, a unique laser pulse with fast rise and fall time was considered for the Cu link structure in the simulation. Results show that the fast rise time laser heats up the upper part of a link rapidly and promotes fast top-oxide cracking, which relieves stress around the metallization faster and thereby avoids undesirable lower-corner cracking. A useful guideline is obtained for the maximum laser energy process window through finite element modeling.