Towards alternative technologies for fine pitch interconnects

This study focuses on alternative technologies for fine pitch 3D interconnect. These technologies are: μ-inserts (insertion of a nickel cylinder in Aluminium pad), μ-tubes (insertion of a hard tube in Aluminium pad), Transient Liquid Phase (TLP) bonding (whole solder reacts to form intermetallic compound) and copper direct bonding. In the first part the process flow is described. Then electrical performances are presented, including a comparison of the Kelvin resistance for each technology. The next part presents reliability considerations, where the failure modes and the weaknesses of each interconnect technologies are described. The mechanical impact of insertion technologies is also studied.