Die to Wafer Direct Hybid Bonding Demonstration with High Alignment Accuracy and Electrical Yields

Abstract

Die-To-Wafer (D2W) direct hybrid bonding is foreseen as a major breakthrough for the future of 3D components; however, its industrialization rises some additional challenges compared to Wafer-To-Wafer processing. This paper presents a 300mm wafer complete solution developed at LETI to improve bonding yield of D2W hybrid bonding using copper interconnections until the assessment of the electrical performances thanks to a dedicated 300mm electrical test vehicle and robust stacking system. Stackings with +/-1.5μm accuracy and excellent bonding interface have been obtained (80% bonding yield). After stacking and annealing, the die can be thinned down to 10μm without damage. Electrical yield measured on daisy-chains with more than 20.000 connections present more than 75% yield and shown very limited drift after preliminary environmental reliability tests. All these results confirmed the high industrial potential of D2W hybrid bonding technology.