Stress evolution in passivated thin films of Cu on silica substrates

Shen, Yu‐Lin; Suresh, S.; He, Ming; Bagchi, Arunabha; Kienzle, O.; Rühle, M.; Evans, A.G.

doi:10.1557/jmr.1998.0272

Cited by 56 publications

(10 citation statements)

References 23 publications

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“…Moreover, conventional theory predicts there is no eect of a very thin passivation layer deposited on top of the free surface. Passivation layers are known to signi®cantly increase the stress changes when the ®lm deforms plastically (Shen et al, 1998). The physical situation at the free surface and the interface are quite dierent.…”

Section: Is a Higher Order Theory Necessary?mentioning

confidence: 99%

Plasticity at the micron scale

Hutchinson

2000

International Journal of Solids and Structures

355

138

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Over a scale which extends from about a fraction of a micron to tens of microns, metals display a strong sizedependence when deformed non uniformly into the plastic range: smaller is stronger. This eect has important implications for an increasing number of applications in electronics, structural materials and MEMS. Plastic behavior at this scale cannot be characterized by conventional plasticity theories because they incorporate no material length scale and predict no size eect. While micron sized solid objects are too small to be characterized by conventional theory, they are usually too large to be amenable to analysis using approaches presently available based on discrete dislocation mechanics. The relatively large numbers of dislocations governing plastic deformation at the micron scale motivate the development of a continuum theory of plasticity incorporating size-dependence. Strain gradient theories of plasticity have been developed for this purpose. The motivation and potential for such theories will be discussed. Important open issues surrounding the foundations of strain gradient plasticity will also be addressed and a few critical experiments identi®ed. #

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Section: Is a Higher Order Theory Necessary?mentioning

confidence: 99%

Plasticity at the micron scale

Hutchinson

2000

International Journal of Solids and Structures

355

138

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“…Accordingly, much attention has been directed to experimentally characterizing the mechanical properties of thin films by a variety of techniques, e.g. (Vlassak and Nix, 1992;Shen et al, 1998;Hommel and Kraft, 2001;Espinosa et al, 2003Espinosa et al, , 2004Dehm et al, 2003;Lou et al, 2003;Phillips et al, 2004;Florando and Nix, 2005;Xiang et al, 2005), and to modeling their size-dependent behavior, e.g (Hutchinson, 2001;Haque and Saif, 2003;Pant et al, 2003;Groh et al, 2003;Von Blanckenhagen et al, 2004;Ghoniem and Han, 2005;Hartmaier et al, 2005;Nicola et al, 2003Nicola et al, , 2005a. Additional references can be found in the works cited.…”

Section: Introductionmentioning

confidence: 99%

Plastic deformation of freestanding thin films: Experiments and modeling

Nicola

Xiang

Vlassak

et al. 2006

Journal of the Mechanics and Physics of Solids

211

140

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“…Much attention has been paid to the thermomechanical response of thin Cu films in recent years. [1][2][3][4][5][6][7][8][9][10][11][12][13] Passivated (encapsulated) Cu films behave differently from their unpassivated counterparts, a feature in contrast with that of Al films, which are mechanically insensitive to artificial passivation (even the unpassivated Al film is inherently coated with a thin layer of native oxide). Mechanical stresses in a passivated Cu film, generated from the thermal mismatch with the substrate, do not relax significantly at elevated temperatures during temperature cycling.…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical response and stress analysis of copper interconnects

Ege

Shen

2003

Journal of Elec Materi

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This study is devoted to thermomechanical response and modeling of copper thin films and interconnects. The constitutive behavior of encapsulated copper film is first studied by fitting the experimentally measured stress-temperature curves during thermal cycling. Significant strain hardening is found to exist. Within the continuum plasticity framework, the measured stress-temperature response can only be described with a kinematic hardening model. The constitutive model is subsequently used for numerical thermomechanical modeling of Cu interconnect structures using the finite element method. The numerical analysis uses the generalized plane strain model for simulating long metal lines embedded within the dielectric above a silicon substrate. Various combinations of oxide and polymer-based low-k dielectric schemes, with and without thin barrier layers surrounding the Cu line, are considered. Attention is devoted to the thermal stress and strain fields and their dependency on material properties, geometry, and modeling details. Salient features are compared with those in traditional aluminum interconnects. Practical implications in the reliability issues for modern copper/low-k dielectric interconnect systems are discussed.

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Stress evolution in passivated thin films of Cu on silica substrates

Cited by 56 publications

References 23 publications

Plasticity at the micron scale

Plasticity at the micron scale

Plastic deformation of freestanding thin films: Experiments and modeling

Thermomechanical response and stress analysis of copper interconnects

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