<title>Thermally induced stresses and electromigration failure</title>

Abstract

Attempts to improve the reliability of narrow passivated Al/Cu conductors as defmed by the performance in an accelerated electromigration test are reviewed. The results are explained in terms of the effect of thermally induced stress and stress voiding on electromigration lifetime. Other processing variations which produced small or inconsequential changes are also discussed. In addition, it was observed that electromigration perfonnance in samples susceptible to stress voiding was degraded as a function of storage time at room temperature.

Temperature Coefficient of Resistance (TCR) Measurement Method to Evaluate Metal Process of CMOS Technology

“…One therefore expects an improvement in EM lifetime by lowering the processing temperature. In a subsequent work [5], Lloyd and co-workers studied interconnect EM performance for different lots with different processing temperatures, and they found approximately five times improvement in EM life-time by reducing dielectric deposition temperature from 390 o C to 325 o C on the interconnect lines.…”

Study on the effectiveness of reservoir length in improving electromigration in Cu/Low-k interconnects

“…Due to tensile stress remaining in the metallization at EM test condition, EM lifetime improvement can be expected by lowering processing temperature. It is found that EM lifetime in interconnect with different porcessing temperature can be approximately five times improvement by reduction of depostion temperature from 390 0 C to 325 0 C in interconnect lines [49]. This great improvement in EM performance is noticed due to the reduction of tensile stress gradient.…”

Electromigration study of through silicon via (TSV)

“…The non-uniform thermal distribution in the test structure induces a thermo-mechanical stress gradient when it is subjected to raised temperature in EM test conditions. It has been reported that the presence of this stress significantly shortens the EM lifetime [39,40].…”