The electromigration short‐length effect in Ti‐AlCu‐Ti metallization with tungsten studs

The electromigration short‐length effect has been investigated by testing a two‐level structure with Ti‐AlCu‐Ti stripes and interlevel tungsten (W) stud vias. This investigation represents a complete study of the short‐length effect using a technologically realistic test structure. Lifetime measurements and resistance changes as a function of time were used to describe this phenomenon, where the latter approach provides new insights into the electromigration behavior of multilayered metallizations. A linear increase in resistance was followed by a resistance change with time that approached zero. For the same product of current density and stripe length, longer stripes increased in resistance to higher values than shorter stripes. The sigma of the lognormal distribution increased as the current density decreased and/or as the maximum allowed resistance change increased. The lifetime, or t50, at relatively small current densities did not obey Black’s empirical equation. Rather, the lifetime data obeyed a m...

[1]  J. Sanchez,et al.  Interpretation of Resistance Changes during Interconnect Reliability Testing , 1994 .

[2]  W. R. Buckland,et al.  Proceedings of the Second Berkeley Symposium on Mathematical Statistics and Probability. , 1952 .

[3]  A. S. Oates,et al.  Comparison of Al electromigration in conventional Al alloy and W‐plug contacts to silicon , 1993 .

[4]  Ronald G. Filippi,et al.  PARADOXICAL PREDICTIONS AND A MINIMUM FAILURE TIME IN ELECTROMIGRATION , 1995 .

[5]  P. Ho,et al.  Electromigration in Al/W and Al(Cu)/W Interconnect Structures , 1991 .

[6]  I. Blech.  Electromigration in thin aluminum films on titanium nitride , 1976 .

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

[8]  Paul S. Ho,et al.  Electromigration failure due to interfacial diffusion in fine Al alloy lines , 1993 .

[9]  E. Colgan,et al.  A review of thin-film aluminide formation , 1990 .

[10]  M. Wood,et al.  Evidence of The Electromigration Short-Length Effect in Aluminum-Based Metallurgy With Tungsten Diffusion Barriers , 1993 .

[11]  Evan G. Colgan,et al.  Kinetics of Al grain growth, Al2Cu precipitation, and dissolution in blanket thin films and fine lines , 1994 .

[12]  C. Hu,et al.  Electromigration in Al(Cu) two-level structures: Effect of Cu and kinetics of damage formation , 1993 .

[13]  Robert W. Bower,et al.  Characteristics of aluminum‐titanium electrical contacts on silicon , 1973 .

[14]  James R. Lloyd,et al.  A model for conductor failure considering diffusion concurrently with electromigration resulting in a current exponent of 2 , 1986 .

[15]  J. E. Freund,et al.  Modern elementary statistics , 1953 .

[16]  Eduard Arzt,et al.  A model for the effect of line width and mechanical strength on electromigration failure of interconnects with “near-bamboo” grain structures , 1991 .

[17]  M. Korhonen,et al.  Stress evolution due to electromigration in confined metal lines , 1993 .

[18]  H.-U. Schreiber,et al.  Electromigration threshold in aluminum films , 1985 .

[19]  C. Thompson,et al.  Analytic model for the grain structures of near‐bamboo interconnects , 1994 .

[20]  Reiner Kirchheim,et al.  Atomistic and computer modeling of metallization failure of integrated circuits by electromigration , 1991 .

[21]  J. Black.  Electromigration failure modes in aluminum metallization for semiconductor devices , 1969 .