Influence of Composition of SiCN as Interfacial Layer on Plasma Activated Direct Bonding

Abstract

Surface activated bonding is more and more attractive as a key technology to realize higher performance CMOS devices independent of scaling. The major challenge of dielectric bonding is to decrease the process temperature in order to be compatible with CMOS processing. In the past, we demonstrated low temperature bonding using SiCN as interfacial dielectric layer, where we have obtained a bond energy above 2.2 J/m 2 with a post bond annealing process of 250°C. In this work, the composition of SiCN was varied aiming at the identification of the key elements taking part in the bonding mechanism. The film density, roughness, CMP outcome, water contact angle and impact of plasma activation have been investigated on three different compositions of SiCN. Bond energy above 2.5 J/m 2 is obtained for the carbon rich SiCN film.

Advanced overlay metrology for 3D NAND bonding applications

“…The approach is limited to bonding substrates with similar form factors, using well-established adhesive, and dielectric fusion bonding techniques. Common materials used for fusion bonding include SiO2 (Silicon dioxide) and SiCN (Silicon Carbon Nitride) [3]- [4]. A significant amount of research has focused on optimizing film stoichiometry, understanding bonding mechanisms, and building a unique toolset that enables high yield with excellent inter-substrate alignment tolerances.…”

Effects of Atomic Ratio on the Mechanical Properties of Amorphous Silicon Carbon Nitride

“…Amorphous ternary silicon carbon nitride (a-SiC N ) is widely used in optoelectronics, coatings, and semiconductor technologies due to its excellent properties, such as wide band gap, high-temperature stability, and outstanding mechanical properties [ 1 , 2 , 3 ]. The a-SiC N films have received extensive attention as copper diffusion barriers and etching stoppers for multi-level interconnects in ultra large-scale integration (ULSI).…”

Film Characterization of Low-Temperature Silicon Carbon Nitride for Direct Bonding Applications

“…Moreover, SiO 2 is known as a less suitable dielectric against Cu diffusion. In our previous reporting, 2,20,21 it was seen that SiCN is a promising alternative dielectric as it possesses essential properties such as high bond strength at lower annealing temperature conditions. In addition, even though SiCN bond annealing was performed at higher temperatures than the deposition temperature, no out-gassing at the interface was observed.…”

“…Surface activated bonding and chemical mechanical polishing (CMP) processes were combined to provide ultra-smooth surfaces, as such direct bonding without adhesive materials can be processed at room temperature while maintaining ultra-fine pitch and high accuracy in wafer-to-wafer stacking. [14][15][16][17][18][19][20][21] In this direct bonding scheme, two different concepts are considered-one is homogeneous bonding as required for 3D sequential integration using dielectric-todielectric and TSVs, and the other is hybrid bonding based on Cu-to-Cu, Cu-to-dielectric, and dielectric-to-dielectric simultaneously bonding. For these bonding structures, dielectric material adjacent to Cu is required to serve not only as an insulator, but also as a mechanical buffer to withstand the grinding process for further 3D integration.…”