Multi-Frequency Processing to Minimize Manufacturing Variation in Micro-Through Via with High Aspect Ratio

摘要

A method for forming a through-via in a laminated substrate by laser drilling the through-via in a laminated substrate from a top exposed surface of the substrate to a bottom exposed surface of the substrate using a plurality of laser pulses that are trepanned in a first predetermined pattern. Each pulse trepanned in the first predetermined pattern has a first energy density per pulse. Then, the through-via is laser drilled using a plurality of laser pulses that are trepanned in a second predetermined pattern. Each pulse trepanned in the second predetermined pattern has a second energy density per pulse that is greater than the first energy density per pulse. The second predetermined pattern is within the first predetermined pattern.