Title :
Electromigration threshold for Cu/low k interconnects
Author :
Lee, Ki-Don ; Ogawa, Ennis T. ; Yoon, Sean ; Lu, Xia ; Ho, Paul S.
Author_Institution :
Lab. for Interconnect & Packaging, Univ. of Texas, Austin, TX, USA
Abstract :
Electromigration (EM) statistics and critical current-density line-length product (jL)c were investigated for Cu interconnects integrated with oxide, CVD low k, porous MSQ, organic polymer dielectrics. The EM activation energy was found to be about 0.8 to 1.0 eV, which is commonly associated with mass transport at the Cu/SiNx cap-layer interface. The lower EM lifetime and threshold product (jL)c can be attributed to a smaller back stress due to less thermomechanical confinement in the low k structures. The confinement effect can be expressed in terms of an effective modulus B to account for EM behavior and threshold products of low k structures. For all the ILDs studied, (jL)c showed no temperature dependence but for the organic polymer, j dependence was observed.
Keywords :
CVD coatings; Young´s modulus; copper; current density; dielectric materials; dielectric thin films; electromigration; integrated circuit interconnections; internal stresses; polymers; silicon compounds; tantalum; Cu-SiNx; Cu-Ta; Cu/SiNx cap-layer interface; Cu/low k interconnects; bulk modulus; critical current density; electromigration threshold; inter level dielectrics; low k CVD; mass transport; organic polymer dielectrics; stress; thermomechanical effect; Dielectric materials; Electromigration; Life testing; Logic testing; Packaging; Performance evaluation; Polymers; Temperature; Thermal stresses; Thermomechanical processes;
Conference_Titel :
Interconnect Technology Conference, 2003. Proceedings of the IEEE 2003 International
Print_ISBN :
0-7803-7797-4
DOI :
10.1109/IITC.2003.1219770
