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

fYear

2003

fDate

2-4 June 2003

Firstpage

259

Lastpage

261

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/SiN_x 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-SiN_x; Cu-Ta; Cu/SiN_x 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;

fLanguage

English

Publisher

ieee

Conference_Titel

Interconnect Technology Conference, 2003. Proceedings of the IEEE 2003 International

Print_ISBN

0-7803-7797-4

Type

conf

DOI

10.1109/IITC.2003.1219770

Filename

1219770