The activation threshold evaluation of metallization for aluminum nitride ceramic under nanosecond laser pulses in air

Abstract Laser activation is an efficient metallization method for producing conductive paths on Aluminum Nitride (AlN) ceramic surface. The problem is that the precipitated aluminum on AlN ceramic is sensitive to laser energy density. The fluence range of laser pulses is the most important parameter to control the activation quality of AlN ceramic. However, It is still very difficult to obtain an accurate value of this parameter, due to the non-uniform intensity distribution of the laser focal spot. Then, a new evaluation method is introduced, by accurately calculating the intensity distribution of the focal spot and changing the scanning velocity. The fluence range of laser pulses is evaluated as 21.53J/(cm^2)~26.02J/(cm^2) for laser activation through the verification experiments. It is also found that the roughness of the flattop laser beam for AlN ceramic should be controlled within ±9.44% when a flattop beam is available.