Finite element simulation of a stress history during the manufacturing process of thin film stacks in VLSI structures

Lee, J.; Mack, Anne Sauter

doi:10.1109/66.705380

Cited by 43 publications

(13 citation statements)

References 23 publications

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“…Thermal stress modeling of Al interconnects and its implications in their structural integrity are relatively well established. [14][15][16][17][18][19][20][21][22][23][24][25][26][27] Such is not the case for Cu-based systems. Available studies 28,29 have used simplified material or mechanical models, as will be discussed in this article.…”

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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Section: Introductionmentioning

confidence: 99%

Thermomechanical response and stress analysis of copper interconnects

Ege

Shen

2003

Journal of Elec Materi

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“…A typical manufacturing process consists of several cycles where the temperature is raised and then cooled down to room temperature. In the present simulations the film is cooled down from 600 to 300 K to simulate the level of stresses at which thin films are subjected during fabrication of microelectronics [30].…”

Section: Resultsmentioning

confidence: 99%

A continuum plasticity model that accounts for hardening and size effects in thin films

Hunter¹,

Kavuri²

2010

Modelling Simul. Mater. Sci. Eng.

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We conducted three-dimensional finite element simulations of the mechanical response of passivated single crystal copper thin films with a continuum crystal plasticity model. The model introduces the formation of high density dislocation layers close to the substrate and passivation interfaces obtained from dislocation dynamics simulations. These dislocation structures are responsible for an increase in strain hardening as the film thickness decreases. The model predicts an increase in strain hardening as the film thickness decreases in agreement with experimental observation in films with thickness in the range 0.2 to 2 µm.

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“…In a finite element study taking into account the stress history during device manufacturing [303], it was illustrated that the final stress state in the metal lines at room temperature resulting from the extensive thermal excursions is essentially the same as that obtained from a single-step modeling of the final cooling process. This suggests that assuming a single cooling step from a stress-free temperature is a reasonable approach to calculate thermal stresses generated in multilevel metal lines.…”

Section: Multilevel Interconnectsmentioning

confidence: 97%

Externally constrained plastic flow in miniaturized metallic structures: A continuum-based approach to thin films, lines, and joints

Shen

2008

Progress in Materials Science

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Finite element simulation of a stress history during the manufacturing process of thin film stacks in VLSI structures

Cited by 43 publications

References 23 publications

Thermomechanical response and stress analysis of copper interconnects

Thermomechanical response and stress analysis of copper interconnects

A continuum plasticity model that accounts for hardening and size effects in thin films

Externally constrained plastic flow in miniaturized metallic structures: A continuum-based approach to thin films, lines, and joints

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