Wafer level build-up stacking process using molten metal filling for multi-chip packaging

TSV (Through-Silicon Via) 3D packaging technology has been and continues to be investigated by many of the semiconductor manufacturer and research institute as a practical way to achieve higher performance and smaller form factors. Compared with conventional 2D packaging, this can increase packing density and reduce power consumption dramatically because of shorter interconnection by vertical directional stacking. So far 3D stacking technology based on W2W bonding has developed widely such as 3D Image sensor and 3D stacking memory because it has the advantage of easier alignment and higher throughput compared with chip-to-chip bonding. However, the wafer level 3D stacking method can be only applicable to products with high production yield because overall yield of 3D stacking chips depends on the yield of multiple stacked layers. In this paper, we suggested wafer level build-up stacking process using oxide bonding and molten metal filling newly, which temporary bonding process is unnecessary and demonstrated it through experiments.