New insights into junction group states modified by surface activation in interlayer dielectrics

Abstract Wafer direct bonding via plasma-assisted activation enables the bonding of interlayer dielectric films in hybrid bonding, achieving higher bonding energies at significantly lower temperatures compared with conventional hydrophilic bonding. The quantity of adsorbed OH groups was used to compare the number of SiOH groups after plasma-assisted activation and vacuum transport. The number of SiOH groups increased by 20% after plasma-assisted activation and water addition compared to the amount present before plasma-assisted activation, then decreased by 20% after vacuum transport. It is believed that the SiOH groups formed through plasma treatment and water addition contributed to the bonding energy. During vacuum transport, SiOH groups on the bonding surface are desorbed, while OH- groups are formed through adsorption. By analyzing changes in the surface state prior to bonding and clarifying their relationship with bonding energy, we achieved stable high-energy bonding exceeding 2.0 J m −2 with low-temperature annealing at 200 °C.