Formation of through-glass vias (TGVs) in glass substrates using femtosecond laser operating in MHz/GHz burst mode

The increasing demand for miniaturized and high-performance consumer electronics has driven advancements in packaging solutions, including the transition to glass interposers. A critical aspect of this development is the fabrication of high-density Through-Glass Vias (TGVs). This study presents the formation of TGVs in various glass substrates using a femtosecond laser FemtoLux 30 operating in MHz/GHz burst modes. By employing burst mode and micromachining methods such as bottom-up milling, TGVs with aspect ratios exceeding 1:80 were achieved, with drilling times as low as 350 ms. The findings demonstrate the potential of GHz burst femtosecond lasers as a high-throughput, precise solution for TGV fabrication.