Electromigration critical length effect in Cu/oxide dual-damascene interconnects

Lee, Ki Don; Ogawa, Ennis T.; Matsuhashi, Hideki; Justison, Patrick; Ko, Kil Soo; Ho, Paul S.; Blaschke, V.

doi:10.1063/1.1418034

Cited by 85 publications

(40 citation statements)

References 6 publications

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“…With j =20 mA m −2 , the jl product for a 50 m line is 10 4 A cm −1 which is comfortably greater than that suggested for void nucleation in copper lines. 33,34 We assume that grain diameters are distributed lognormally, with a median value of d 50 = 0.5 m and lognormal deviation of d = 0.36, values obtained for 0.35 m lines, 35 although we shall regard these parameters as variables to some extent.…”

Section: Failure Time Distributionmentioning

confidence: 99%

Modeling the electromigration failure time distribution in short copper interconnects

Dwyer

2008

Journal of Applied Physics

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The electromigration (EM) lifetime in short copper interconnects is modeled using a previously developed means of generating realistic interconnect microstructures combined with the one-dimensional stress evolution equation of Korhonen et al. [J. Appl. Phys. 73, 3790 (1993)]. This initial analysis describes the void nucleation and subsequent growth in lines blocked at one end and terminated with a pad at the other. For short copper interconnects, the failure time is largely spent on void growth, and, for sufficiently short lines (≲50 mm), the growth is largely steady state. This allows for the development of a simple expression for the variation of the failure time with microstructure. Assuming that the diffusion activation energies are normally distributed, the permanence property of summed lognormals leads to a roughly lognormal distribution for EM failure times. Importantly for EM design rules, linear extrapolation on lognormal plot is found to slightly underestimate interconnect reliability.

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Section: Failure Time Distributionmentioning

confidence: 99%

Modeling the electromigration failure time distribution in short copper interconnects

Dwyer

2008

Journal of Applied Physics

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“…This case, which is valid for unpassivated lines [4], has also been used consistently in the case of passivated lines [3,[5][6][7][8][9][10][11][12][13][14]. In passivated lines, unless the anode is steadily leaking copper into the surrounding dielectric stack, the steady-state occurs only when 0  drift v .…”

Section: Introductionmentioning

confidence: 96%

“…This is known as the short line effect, and can be vital in Electromigration-aware chip design as, by daisy chaining long interconnects, say in M1 and M2 sections, all lines can conceivably be made sufficiently short that EM ceases, this defines a critical or Blech length. In recent years a number of studies of the short line effect in DD copper have been reported [3,[5][6][7][8][9][10][11][12][13][14] some of which have indeed daisy chained interconnects of different lengths to increase the efficiency of the experiment. The purpose of this paper is to analyse that work using what might be described as standard theory for Electromigration [1].…”

Section: Introductionmentioning

confidence: 99%

Analysis of critical-length data from Electromigration failure studies

Dwyer

2011

Microelectronics Reliability

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“…Recently, during several failure tests, it has been observed that copper nano vias are literally destroyed (Figure 1) under high fluence stress [1][2][3][4][5][6]. This may find an explanation by localized heating due to Joule effect, but first order calculations based on simplified thermal considerations show rather low temperature in order to explain void presence in the nano vias, which such be over, at least, copper silicate formation temperature (823 K) [1][2][3][4][5][6][7]. In order to assure reliability and improvement on nano scales, it is necessary to understand the degradation process of these devices.…”

Section: Introductionmentioning

confidence: 99%

Análisis termo-eléctrico de elementos finitos (EF) en vías de cobre nanométricas bajo tensión de alta fluencia

Oviedo

Trojman

Kauerauf

et al. 2013

Av. Cienc. Ing. (Quito)

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This paper presents the development of a thermal-electrical finite element (FE) model with the objective to analyze failure mechanisms responsible of physical degradation (void, copper silicate formation, etc.) caused by high fluence stress of 90nm copper vias for FinfET devices. Indeed in [1], this physical degradation was interpreted as a main consequence of Joule effect, however their employed model reached too low temperatures to explain the observed physical degradation. In order to confirm this, the steady-state FE model developed in this work computes the temperature increase and distribution caused by high electrical current density flowing through a copper contact, considering non-ideal thermal and electrical interfaces. In addition, a sensitivity analysis is performed as a way to identify critical failure parameters. The temperature response of the model to independent variation of electrical resistivity of studied materials, and interfacial electrical and thermal conductance between the copper contact and its diffusion barrier were obtained. The decrease of interfacial electrical conductance triggers steady-state temperatures over copper and silicate melting points and, in consequence leads to temperature high enough to explain the physical degradation.Keywords. copper nano vias, Joule heating, finite element analysis, interface electric conductivity, sensitivity analysis. ResumenEste trabajo presenta el desarrollo de un modelo termo-eléctrico de elementos finitos (EF) con el fin de analizar los mecanismos de falla responsables de la degradación física causada por alta densidad de corriente en contactos de cobre de 90 nm empleados en dispositivos FinFET. De hecho en [1], esta degradación física fue interpretada como consecuencia principal del efecto Joule, sin embargo el modelo empleado alcanzó temperaturas demasiado bajas comparadas con el daño observado. Con el propósito de confirmar esta hipótesis, el modelo de EF de estado estable desarrollado en este trabajo calcula el incremento y la distribución de temperatura causada por alta densidad de corriente eléctrica fluyendo a través de un contacto de cobre, tomando en cuenta interfaces eléctricas y térmicas no idealizadas. Además, un análisis de sensibilidad fue realizado como un medio para identificar parámetros críticos de falla. La respuesta del modelo ante la variación independiente de la resistividad eléctrica de los materiales estudiados, y las conductancias eléctricas y tér-micas entre el contacto de cobre y su barrera de difusión fue obtenida. La disminución de la conductancia eléctrica de dicha interfaz desencadenó temperaturas de estado estable superiores a los puntos de fusión del cobre y los silicatos del contacto y, en consecuencia, permite explicar la degradación física observada.Palabras Clave. nano contactos de cobre, calentamiento Joule, análisis de elementos finitos, conductividad eléctrica de interfaz, análisis de sensibilidad.

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Electromigration critical length effect in Cu/oxide dual-damascene interconnects

Cited by 85 publications

References 6 publications

Modeling the electromigration failure time distribution in short copper interconnects

Modeling the electromigration failure time distribution in short copper interconnects

Analysis of critical-length data from Electromigration failure studies

Análisis termo-eléctrico de elementos finitos (EF) en vías de cobre nanométricas bajo tensión de alta fluencia

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