Numerical simulation of stressmigration in interconnects with air-gap structures

This work investigates the impact of the dielectric material on the stressmigration based on modeling of 3D numerical simulations. Particularly noteworthy is the study for structures that incorporate so-called air-gaps. Contrary to the expected, the stress developed in the AG structure was larger than in the standard ones. The standard structure with SiCOH shows a magnitude of 450 MPa at the Cu/capping layer interface, while in the air-gap structure the magnitude is 550 MPa, an increase of 22 %. Nevertheless, the simulation results indicate that the introduction of air-gap technology does not affect the reliability of metallization from the point of view of stressmigration.