Development of a High Metal Ionization Physical Vapor Deposition System for High Aspect Ratio Through-Glass-Via Metallization

One of the key technologies for developing vertically interconnected three-dimensional packaging involves the use of through-silicon vias or through-glass vias for interlayer metallization. In the electroplating process, the thickness distribution of the seed layer significantly influences via filling performance. In this study, we developed an ionized metal plasma sputtering system capable of achieving complete copper seed layer coverage on via sidewalls. A comprehensive comparison was conducted with conventional sputtering systems to evaluate their respective via coating capabilities. The thickness distribution of seed layers within vias was systematically characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy. These results conclusively demonstrate that our self-developed IMP system successfully overcomes the limitations of conventional PVD for low aspect ratios (AR < 5:1) via metallization in advanced 3D integration schemes, and this system demonstrates the capability to achieve conformal metal seed layer deposition on large-format glass substrates (510 mm×515 mm) with high aspect ratio (AR ≥ 15:1) features, with step coverage (SC ≥ 5%), while maintaining 100% electrical connectivity yield in subsequent electroplating processes. This research represents a significant milestone in advancing the localization of semiconductor equipment manufacturing.