Identification and Analysis of Dominant Electromigration Failure Modes in Copper/Low-K Dual Damascene Interconnects

AbstractElectromigration reliability in Cu dual-damascene interconnects with a CVD MSQ low k dielectric was investigated. Statistical studies were carried out using the critical length (LC) test structures containing multi-link line/via elements with varying line lengths. EM lifetime characteristics, critical current density-length product (jL)c, and failure mechanisms were discussed and compared with Cu/oxide structures. Our results suggested that the diffusion at the cap layer interface was the dominant mechanism for EM mass transport. The confinement effect, in terms of an effective modulus B, can be used to account for the shorter EM lifetime and smaller critical current density-length product (jL)c observed for Cu/CVD MSQ low k interconnects. Failure analysis by FIB confirmed the presence of multiple failure modes including voiding at the via bottom, Cu extrusion and delamination at Cu/cap layer interface.

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Novel Cu reflow seed process for Cu/low-k 64nm pitch dual damascene interconnects and beyond

2012 IEEE International Interconnect Technology Conference ◽

10.1109/iitc.2012.6251656 ◽

2012 ◽

Author(s):

K. Motoyama ◽

O. van der Straten ◽

H. Tomizawa ◽

J. Maniscalco ◽

S.T. Chen

Keyword(s):

Dual Damascene ◽

Damascene Interconnects ◽

Low K

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Via-Shape-Control for Copper Dual-Damascene Interconnects With Low-k Organic Film

IEEE Transactions on Semiconductor Manufacturing ◽

10.1109/tsm.2008.2000268 ◽

2008 ◽

Vol 21 (2) ◽

pp. 256-262 ◽

Cited By ~ 4

Author(s):

Keizo Kinoshita ◽

Munehiro Tada ◽

Masayuki Hiroi ◽

Kazutoshi Shiba ◽

Takahiro Onodera ◽

...

Keyword(s):

Shape Control ◽

Organic Film ◽

Dual Damascene ◽

Damascene Interconnects ◽

Low K

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Misalignment-tolerated, Cu dual damascene interconnects with low-k SiOCH film by a novel via-first, multi-hard-mask process for sub-100nm-node, ASICs

IEEE International Electron Devices Meeting 2003 ◽

10.1109/iedm.2003.1269413 ◽

2004 ◽

Cited By ~ 1

Author(s):

H. Ohtake ◽

M. Tagami ◽

K. Arita ◽

Y. Hayashi

Keyword(s):

Hard Mask ◽

Dual Damascene ◽

Damascene Interconnects ◽

Low K

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Via Electromigration Lifetime Improvement of Aluminum Dual-Damascene Interconnects by Using Soft Low-k Organic SOG Interlayer Dielectrics

MRS Proceedings ◽

10.1557/proc-612-d2.5.1 ◽

2000 ◽

Vol 612 ◽

Author(s):

Hisashi Kaneko ◽

Takamasa Usui ◽

Sachiyo Ito ◽

Masahiko Hasunuma

Keyword(s):

Tensile Stress ◽

Young’S Modulus ◽

Young's Modulus ◽

Void Nucleation ◽

Dielectric Materials ◽

Dual Damascene ◽

Atom Migration ◽

Multi Level ◽

Damascene Interconnects ◽

Low K

AbstractThe via electromigration(EM) reliability of aluminum(Al) dual-damascene interconnects by using Niobium(Nb) new reflow liner is described. It has been found that the via EM lifetime was improved by introducing low-k organic spin on glass(SOG)-passivated structure than the conventional TEOS-SiO2/SiN-passivated structure. Higher EM activation energy of 1.08 eV was obtained for the SOG-passivated structure than the conventional TEOS-passivated structure of 0.9 eV, even though no significant Al micro-crystal structure difference was found for both structures. It has been turned out that the low-k SOG material has the 1/7 Young's modulus (8 GPa) of TEOS-SiO2 (57 GPa) or thermal SiO2(70 GPa). The small Young's modulus means that SOG is more elastically deformable and/or softer than TEOS or thermal SiO2. This elastic deformation of the low-k SOG could retard the tensile stress evolution due to the Al atom migration near the cathode via, and elongated the time until the Al interconnect tensile stress exceeds the critical stress value for void nucleation. It has been concluded that the small-RC and reliable multi-level Al interconnect can be realized by the Nb-liner reflow-sputtered process with soft and low-k SOG dielectric materials.

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