Low-Temperature Femtosecond Laser Processing for Enhanced Via Hole Morphology in Semiconductor Packaging

This study compares plasma damage during femtosecond laser processing of via holes at room-temperature (25°C) and low-temperature (−20°C). At room-temperature, significant debris redeposition and plasma-induced residual tensile stresses were observed. In contrast, the ice layer at low-temperature reduced debris redeposition, reduced the plasma-damaged region to approximately half its length, and suppressed plasma-induced residual tensile stresses. These results highlight the effectiveness of low-temperature processing in reducing plasma-damaged region and improving via hole morphology quality.