Electromigration Failure in Thin Film Conductors Possessing a Near-Bamboo Structure

1994 ◽  
Vol 338 ◽  
Author(s):  
J.R. Lloyd
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Stress Gradient ◽  
Diffusion Path ◽  
Flux Divergence ◽  
Cluster A ◽  
Bamboo Structure

ABSTRACTElectromigration failure in a near bamboo structure is investigated theoretically. Assuming that the diffusion path is interfacial, a flux divergence can be predicted based on the stress gradient induced by grain boundary electromigration in a sub Blech Length grain cluster. A possible explanation for the recently observed “trans-granular” voids is proposed.

The Effect of Variability Among Grain Boundary Energies on Grain Growth in Thin Film Strips

1994 ◽  
Vol 338 ◽  
Author(s):  
H.J. Frost ◽  
Y. Hayashi ◽  
C.V. Thompson ◽  
D.T. Walton
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Grain Growth ◽  
Boundary Energy ◽  
Strip Width ◽  
Grain Boundary Energy ◽  
Triple Junctions ◽  
Interconnect Reliability ◽  
Bamboo Structure ◽  
Grain Boundary Pinning

ABSTRACTGrain growth in thin-film strips is important to interconnect reliability because grain boundary structures strongly effect the rate and mechanism of electromigration-induced failure. Previous simulations of this process have indicated that the transformation to the fully bamboo structure proceeds at a rate which decreases exponentially with time, and which is inversely proportional to the square of the strip width. We have also reported that grain boundary pinning due to surface grooving implies that there exists a maximum strip width to thickness ratio beyond which the transformation to the bamboo structure does not proceed to completion. In this work we have extended our simulation of grain growth in thin films and thin film strips to consider the effects of variations in grain boundary energy. Boundary energy is taken to depend on the misorientation between the two neighboring grain and the resulting variations in grain boundary energy mean that dihedral angles at triple junctions deviate from 120°. The proportionality between boundary velocities and local curvatures, and the critical curvature for boundary pinning due to surface grooving also both depend on boundary energy. In the case of thin-film strips, the effect of boundary energy variability is to impede the transformation to the bamboo structure, and reduce the width above which the complete bamboo structure is never reached. Those boundaries which do remain upon stagnation tend to be of low energy (low misorientation angle) and are therefore probably of low diffusivity, so that their impact on reliability is probably reduced.

Void Intergranual Motion Under the Action of Electromigration Forces in Thin Film Interconnects with Bamboo Structure

2001 ◽  
Vol 695 ◽  
Author(s):  
Ersin Emre Oren ◽  
Tarik Omer Ogurtani
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Entropy Production ◽  
Computer Simulations ◽  
Triple Junction ◽  
Tearing Mode ◽  
Virtual Displacement ◽  
Component Systems ◽  
Bamboo Structure ◽  
Metallic Interconnects

ABSTRACTThe rigorous formulation of the internal entropy production, and the generalized forces and conjugate fluxes associated with the virtual displacement of a triple junction are presented in multi-component systems. Extensive computer simulations are performed on the void configurational evolution during the intergranual motion; under the actions of capillary and electromigration forces in thin film metallic interconnects with bamboo structure having various grain textures. The texture studies in this work show clearly that there are two different and very distinct modes, namely: the grain boundary carving or tearing mode, and the interconnect edge cutting mode by the oblique slit formation (about 450) on the wind-side of the grain boundary.

Grain Boundary Grooving as the Mechanism of the Blech Electromigration in Interconnects

1995 ◽  
Vol 391 ◽  
Author(s):  
E.E. Glickman ◽  
L.M. Klinger
Keyword(s):  
Grain Boundary ◽  
Surface Diffusion ◽  
Current Density ◽  
High Current Density ◽  
Diffusion Flux ◽  
Stress Gradient ◽  
Displacement Velocity ◽  
Gradual Transition ◽  
Flux Divergence ◽  
New Approach

AbstractWe present a new approach to understand the mechanism of "homogeneous", or Blech electromigration (EM). This phenomenon describes macroscopically homogeneous displacement of the up-wind edge of thin film lines in microelectronic devices and is responsible for openings at contact windows, "vias" and other sites of perfect diffusion flux divergence.Our SEM, EPMA and EM drift velocity experiments have revealed the gradual transition from the microscopically homogeneous EM displacement to the highly nonhomogeneous mode wherein copious islands of residual material remain behind the drifting cathode edge of aluminum stripes. The transition is shown to occur due to an increase in either the current density, j, or in the stripe length, 1. The latter case suggests, that the transition results from the growth of the net grain boundary (GB) diffusion flux, I=le-Ib ,where Ie∝j and 1b∝1/1 are the EM flux and stress-gradient-driven back flux, respectively.Based upon recent progress in the theory of GB grooving under "external" GB fluxes, with surface diffusion acting as the healing mechanism, grooves' propagation along the line and their merging is considered to be the micromechanism of the "homogeneous" EM. In terms of the simple model described, the transition from the slow receding of the cathode butt edge slightly wrinkled by shallow grooves (A-regime of EM) to the fast extension and merging of slot -like grooves (B-regime) accounts for the transition observed in EM mode, while in both regimes the EM displacement velocity, V, is presumed to represent the groove propagation rate.The theory developed reduces to Blech formulae for V for the truly homogeneous A-regime and predicts quite different EM kinetics for the B-regime of microscopically nonhomogeneous EM. The latter is expected to dominate for films loaded by high current density with large grains and low surface diffusion.The dependence obtained for the residual mass left behind the drifted edge vs the displacement velocity, V, for unpassivated aluminum stripes of various lengths, loaded by j=2-106 A/cm2 at 548K provides a good evidence in support of a new approach.

Computer Simulation of Grain Growth in Thin-film Interconnect Lines

1991 ◽  
Vol 225 ◽  
Author(s):  
D. T. Walton ◽  
H. J. Frost ◽  
C. V. Thompson
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
Grain Growth ◽  
Integrated Circuit ◽  
Strip Width ◽  
Grain Structure ◽  
Time To Failure ◽  
Interconnect Reliability ◽  
Bamboo Structure ◽  
Individual Grains

ABSTRACTMicrostructural evolution in thin-film strips is of interest due to the direct effect of grain structure on integrated circuit interconnect reliability and resistance to electromigration-induced failure. We have explored the evolution of interconnect grain structure via a two-dimensional grain growth simulation. We focus on the strip's transformation to the bamboo structure, in which individual grains traverse the width of the strip. We find that the approach to a fully bamboo structure is exponential, and that the rate of transformation is inversely proportional to the square of the strip width. When the simulation is extended to model grain boundary pinning due to grooving at grain boundary – free surface intersections, we find that there exists a maximum strip width to thickness ratio beyond which the transformation to the bamboo structure does not proceed to completion. By using our simulation results in conjunction with a “failure unit” model for electromigration-induced failure [4] we are able to reproduce the experimentally observed abrupt increase in time-to-failure below a critical strip width, and also model the reliability as a function of annealing conditions.

On the role of tin underlays for the prevention of thermal grooving in thin gold films

1986 ◽  
Vol 44 ◽  
pp. 732-733
Author(s):  
Jin Young Kim ◽  
R. E. Hummel ◽  
R. T. DeHoff
Keyword(s):  
Thin Film ◽  
Free Surface ◽  
Grain Boundary ◽  
Beneficial Effect ◽  
Failure Mechanism ◽  
Failure Mechanisms ◽  
Distinct Advantage ◽  
Gold Films ◽  
Gold Thin Film

Gold thin film metallizations in microelectronic circuits have a distinct advantage over those consisting of aluminum because they are less susceptible to electromigration. When electromigration is no longer the principal failure mechanism, other failure mechanisms caused by d.c. stressing might become important. In gold thin-film metallizations, grain boundary grooving is the principal failure mechanism.Previous studies have shown that grain boundary grooving in gold films can be prevented by an indium underlay between the substrate and gold. The beneficial effect of the In/Au composite film is mainly due to roughening of the surface of the gold films, redistribution of indium on the gold films and formation of In2O3 on the free surface and along the grain boundaries of the gold films during air annealing.

scholarly journals Microstructure and Magnetic Properties of NdFeB Sintered Magnets Diffusion-Treated with Cu/Al Mixed Dyco Alloy-Powder

2017 ◽  
Vol 62 (2) ◽  
pp. 1263-1266 ◽  
Author(s):  
M.-W. Lee ◽  
K.-H. Bae ◽  
S.-R. Lee ◽  
H.-J. Kim ◽  
T.-S. Jang
Keyword(s):  
Grain Boundary ◽  
Diffusion Path ◽  
Boundary Phase ◽  
Core Shell ◽  
Phase Layer ◽  
Sintered Magnets ◽  
The Core ◽  
Shell Type ◽  
Property Changes ◽  
And Diffusion

AbstractWe investigated the microstructural and magnetic property changes of DyCo, Cu + DyCo, and Al + DyCo diffusion-treated NdFeB sintered magnets. The coercivity of all diffusion treated magnet was increased at 880ºC of 1stpost annealing(PA), by 6.1 kOe in Cu and 7.0 kOe in Al mixed DyCo coated magnets, whereas this increment was found to be relatively low (3.9 kOe) in the magnet coated with DyCo only. The diffusivity and diffusion depth of Dy were increased in those magnets which were treated with Cu or Al mixed DyCo, mainly due to comparatively easy diffusion path provided by Cu and Al because of their solubility with Ndrich grain boundary phase. The formation of Cu/Al-rich grain boundary phase might have enhanced the diffusivity of Dy-atoms. Moreover, relatively a large number of Dy atoms reached into the magnet and mostly segregated at the interface of Nd2Fe14B and grain boundary phases covering Nd2Fe14B grains so that the core-shell type structures were developed. The formation of highly anisotropic (Nd, Dy)2Fe14B phase layer, which acted as the shell in the core-shell type structure so as to prevent the reverse domain movement, was the cause of enhancing the coercivity of diffusion treated NdFeB magnets. Segregation of cobalt in Nd-rich TJP followed by the formation of Co-rich phase was beneficial for the coercivity enhancement, resulting in the stabilization of the metastable c-Nd2O3phase.

Spatially resolved investigation of the defect states in methylammonium lead iodide perovskite bicrystals

2019 ◽  
Vol 7 (42) ◽  
pp. 13156-13160 ◽  
Author(s):  
Svetlana Sirotinskaya ◽  
Christian Fettkenhauer ◽  
Daichi Okada ◽  
Yohei Yamamoto ◽  
Doru C. Lupascu ◽  
...  
Keyword(s):  
Thin Film ◽  
Grain Boundary ◽  
System Approach ◽  
Defect States ◽  
Lead Iodide ◽  
Modal System ◽  
Trap Formation ◽  
Spatially Resolved ◽  
Methylammonium Lead Iodide

Introducing a modal system approach for the analytical perovskite thin-film trap physics evaluation. Our study confirms existing models for trap formation in MAPI, substantiating different defect states in the grain boundary and bulk regions.

Sign in / Sign up

Export Citation Format

Share Document