A novel diffusion barrier of electrodeposited CoWP layer between copper and silicon: Preparation and performance

In order to solve the interconnection failure caused by the diffusion between copper and silicon in electrical circuit, a novel diffusion barrier of electrodeposited CoWP layer was developed in our work. By adjusting bath pH and temperature, the electrodeposition conditions of CoWP layer were optimized. The CoWP barrier with amorphous structures was successfully obtained. The barrier performance and the failure mechanism of the electrodeposited CoWP layer for Cu/Si interconnection were systematically investigated. The results showed that the CoWP layer could prevent the diffusion of copper and silicon and exhibited excellent barrier performance below the annealing temperature of 800 degrees C for 30 min. At higher annealing temperatures, high-resistance compounds Cu3Si appeared on the surface of the silicon, indicating the failure of CoWP layer due to the diffusion between copper and silicon. Failure mechanism of CoWP layer in Cu/Si interconnection was confirmed to the reaction between cobalt and silicon, which provided a path for copper diffusing into the silicon. By modifying the thickness of diffusion barrier layer, it was found that the failure occurred easily when the CoWP layer was thinner than 0.76 mu m after annealing at 500 degrees for 30 min.

Automated summary

A novel diffusion barrier of electrodeposited CoWP layer was developed to prevent interconnection failure caused by diffusion between copper and silicon, with amorphous structures and optimal thickness identified.