Main reliability challenges with copper TSV´s

Summary form only given. Due to their large volume and close proximity to devices, the reliability of copper TSV´s is a concern, both with respect to mechanical stresses induced by the TSV in the Si and with respect to copper drift into the liner and the Si. This tutorial summarizes achievements obtained in imec´s 3D-reliability work package where above mentioned reliability concerns are evaluated in detail. Three main concerns will be dealt with. First, the phenomenon of copper pumping where copper extrudes at the TSV-top during high temperature anneal is introduced and the physics behind this phenomenon are explained and possible solutions are proposed. Then, barrier/liner integrity concerns are expressed. Barrier/liner integrity is needed to avoid copper diffusion from the TSV into the Si. This part of the tutorial deals with methods to evaluate this integrity. The last part of the talk will be contributed to studies where the stability of the stress that is generated by the copper into the Si is evaluated over time.