Review—Hybrid Bonding-Based Interconnects: A Status on the Last Robustness and Reliability Achievements

Abstract

This paper reviews the most significant qualification and reliability achievements obtained, over the last 6 years, by the scientific community for hybrid bonding-based interconnects (HB) also called Cu-Cu or Cu/SiO2 bonding. First, the definition of words qualification, robustness and reliability are given to avoid misunderstanding about the published results. Second, the five potential threats (moisture ingress, thermomechanical stresses,electromigration, Cu diffusion, dielectric breakdown) are presented. Finally, the publications of six industrials or research and technology organizations are summarized and discussed. Most of the published data are related to qualification results (pass or fail). Few studies published in-depth studies, mainly on electromigration (Black’s parameters extraction and failure analysis) and copper diffusion (electrical and analytical characterizations). To conclude, once the manufacturing issues (surface preparation, alignment…) have been solved, this technology is robust and reliable at pitches > 1 μm as it reacts, roughly, like a conventional back-end of line (BEoL) interconnect.

Advanced Cu/Polymer Hybrid Bonding System for Fine‐Pitch 3D Stacking Devices

“…For such technologies to secure mass production capability, not only should the chip yield be high in the front-end process but also reliable bonding technology should be supported. [10][11][12] In the HI, technical challenges are to form the through Si via (TSV) on the chips and to attach them with high accuracy. Interestingly, there is also a scaling issue in the HI.…”

“…For such technologies to secure mass production capability, not only should the chip yield be high in the front‐end process but also reliable bonding technology should be supported. [ 10–12 ]…”

(Invited) Hybrid Bonding for 3D Applications: Improvements and Limitations

“…Products are now available with interconnexion pitch around 1 µm [5]. The integration can be realized using SiN, SiCN or SiO2 at the bonding interface while copper for pads is the principal bonding metal used [6]. The achievement of a high quality for hybrid bonding requires perfect surface cleanliness, low roughness and low topography of the surfaces to be bonded.…”

Hydrophilic Bonding of SiO2/SiO2 and Cu/Cu using Sequential Plasma Activation

“…However, traditional methods such as soldering or bump bonding cannot handle high density interconnection. Therefore, hybrid bonding technology, which simultaneously bonds Cu wiring layers and SiO2 dielectric layers, is indispensable (1). In the hybrid bonding process, hydrophilic bonding is commonly used to bond SiO2 to SiO2.…”