Fine pitch 3D interconnections with hybrid bonding technology: From process robustness to reliability

This paper presents the description of direct hybrid bonding technology for the fabrication of vertical interconnects thanks to wafer-to-wafer bonding. Process robustness is analyzed through morphological and electrical results. The electrical characterizations are discussed versus hybrid bonding pad dimensions and pitches. Electromigration study is carried out on different test vehicles with hybrid bonding interconnect dimensions below 5 μm. Experimental tests provide the parameters for lifetime extrapolation and show that the hybrid bonding module is immune to electromigration failures. Finally perspectives and key challenges for 3D interconnects scalability are given.