A low-cost spin-on-glass (SOG) liner deposited by vacuum-assisted spin coating technique for via-last ultra-high aspect ratio through-silicon vias

This paper presents a spin on glass (SOG) liner formed by vacuum-assisted spin coating (VASC) technique for via last 3D integration applications. In comparison to SiO
2
liners produced through traditional methods such as thermal oxidation or chemical vapor deposition (CVD), the proposed approach is simpler and more cost-effective. This methodology successfully achieved a conformal SOG liner within silicon blind vias measuring 6 μm in diameter, 90 μm in depth, and with an aspect ratio of 15:1. The influences of spinning time and SOG solid content on the morphology of the formed liner were investigated in this work. Results show that this method has excellent performance in through silicon vias (TSVs) with small diameter and ultra-high aspect ratio (UHAR). In addition, the deposition of the SOG liner is highly compatible with CMOS technology, and the process can be carried out at a maximum temperature of approximately 200 ℃. As a result, it is suitable for implementation in via-last 3D integration applications.