The first observation of p-type electromigration failure in full ruthenium interconnects

We show the first electromigration (EM) failures of full ruthenium interconnects with a cross sectional area of 60nm2. The void is observed at the anode, which demonstrates that in p-type metals, such as Ru, the electromigration force acts in the direction of the electric field. The conventional representation of electromigration as electrons transferring their momentum onto the metal ions, thus has to be adapted for such metals. Moreover, we find that diffusion at the Ru-SiO2 interface is the dominant diffusion mechanism for EM failure in these specific Ru lines.

[1]  M. Steeves,et al.  Charge transport in flat and nanorod structured ruthenium thin films , 2010 .

[2]  F. Mont,et al.  Electromigration and resistivity in on-chip Cu, Co and Ru damascene nanowires , 2017, 2017 IEEE International Interconnect Technology Conference (IITC).

[3]  M. H. van der Veen,et al.  Study of electromigration mechanisms in 22nm half-pitch Cu interconnects by 1/f noise measurements , 2017, 2017 IEEE International Interconnect Technology Conference (IITC).

[4]  P. Ho,et al.  Electromigration in metals , 1989 .

[5]  Christopher J. Wilson,et al.  Ruthenium interconnects with 58 nm2 cross-section area using a metal-spacer process , 2017, 2017 IEEE International Interconnect Technology Conference (IITC).

[6]  E. T. Ryan,et al.  Cobalt interconnect on same copper barrier process integration at the 7nm node , 2017, 2017 IEEE International Interconnect Technology Conference (IITC).

[7]  P. Kapur,et al.  Technology and reliability constrained future copper interconnects. I. Resistance modeling , 2002 .

[8]  A. S. Oates,et al.  The impact of trench width and barrier thickness on scaling of the electromigration short - Length effect in Cu / low-k interconnects , 2013, 2013 IEEE International Reliability Physics Symposium (IRPS).

[9]  Christoph Adelmann,et al.  Alternative metals for advanced interconnects , 2014, IEEE International Interconnect Technology Conference.

[10]  C. Auth,et al.  A 10nm high performance and low-power CMOS technology featuring 3rd generation FinFET transistors, Self-Aligned Quad Patterning, contact over active gate and cobalt local interconnects , 2017, 2017 IEEE International Electron Devices Meeting (IEDM).

[11]  M. H. van der Veen,et al.  Reliability study on cobalt and ruthenium as alternative metals for advanced interconnects , 2017, 2017 IEEE International Reliability Physics Symposium (IRPS).

[12]  Jasprit Singh,et al.  Electronic and Optoelectronic Properties of Semiconductor Structures , 2007 .

[13]  Christopher J. Wilson,et al.  Ruthenium metallization for advanced interconnects , 2016, 2016 IEEE International Interconnect Technology Conference / Advanced Metallization Conference (IITC/AMC).

[14]  H. Bender,et al.  Atomic Layer Deposition of Ruthenium Thin Films from (Ethylbenzyl) (1-Ethyl-1,4-cyclohexadienyl) Ru: Process Characteristics, Surface Chemistry, and Film Properties , 2017 .

[15]  K. Sankaran,et al.  Thickness dependence of the resistivity of platinum-group metal thin films , 2017, 1701.04124.

[16]  Klaus Fuchs,et al.  The conductivity of thin metallic films according to the electron theory of metals , 1938, Mathematical Proceedings of the Cambridge Philosophical Society.

[17]  D. Gall.  Electron mean free path in elemental metals , 2016 .

[18]  B. Agarwala,et al.  Scaling effect on electromigration in on-chip Cu wiring , 1999, Proceedings of the IEEE 1999 International Interconnect Technology Conference (Cat. No.99EX247).

[19]  Christopher J. Wilson,et al.  Highly Scaled Ruthenium Interconnects , 2017, IEEE Electron Device Letters.

[20]  M. Shatzkes,et al.  Electrical-Resistivity Model for Polycrystalline Films: the Case of Arbitrary Reflection at External Surfaces , 1970 .

[21]  P. Ho,et al.  Electromigration and soret effect in cobalt , 1966 .

[22]  Christopher J. Wilson,et al.  Atomic Layer Deposition of Ruthenium with TiN Interface for Sub-10 nm Advanced Interconnects beyond Copper. , 2016, ACS applied materials & interfaces.

[23]  Wei Wang,et al.  Ruthenium interconnect resistivity and reliability at 48 nm pitch , 2016, 2016 IEEE International Interconnect Technology Conference / Advanced Metallization Conference (IITC/AMC).

[24]  H. B. Huntington,et al.  Current-induced marker motion in gold wires☆ , 1961 .

[25]  M. Polcari,et al.  Observation of electromigration in heavily doped polycrystalline silicon thin films , 1980 .

[26]  Cher Ming Tan,et al.  Investigation of the effect of temperature and stress gradients on accelerated EM test for Cu narrow interconnects , 2006 .

[27]  Anthony S. Oates,et al.  Strategies to Ensure Electromigration Reliability of Cu/Low-k Interconnects at 10 nm , 2015 .

[28]  K. Sankaran,et al.  Exploring Alternative Metals to Cu and W for Interconnects Applications Using Automated First-Principles Simulations , 2015 .