Hillock formation during electromigration in Cu and Al thin films: Three-dimensional grain growth

Gladkikh, A.; Lereah, Y.; Glickman, E.; Karpovski, M.; Palevski, A.; Schubert, J.

doi:10.1063/1.113240

Cited by 47 publications

(31 citation statements)

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“…Wei et al (2002) believe that these are likely to be new nucleated grains, whereas Gladkikh et al (1995) believe that they result from the growth of a neighbouring grain. Let us now consider the hillock on a copper film shown in the EBSD map in Fig.…”

Section: Local Environment Of a Hillock On A Copper Filmmentioning

confidence: 99%

Multiple twinning in cubic crystals: geometric/algebraic study and its application for the identification of the Σ3ⁿgrain boundaries

Cayron

2006

Acta Crystallogr A Found Crystallogr

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Multiple twinning in cubic crystals is represented geometrically by a threedimensional fractal and algebraically by a groupoid. In this groupoid, the variant crystals are the objects, the misorientations between the variants are the operations, and the AE3 n operators are the different types of operations (expressed by sets of equivalent operations). A general formula gives the number of variants and the number of AE3 n operators for any twinning order. Different substructures of this groupoid (free group, semigroup) can be equivalently introduced to encode the operations with strings. For any coding substructure, the operators are expressed by sets of equivalent strings. The composition of two operators is determined without any matrix calculation by string concatenations. It is multivalued due to the groupoid structure. The composition table of the operators is used to identify the AE3 n grain boundaries and to reconstruct the twin related domains in the electron back-scattered diffraction maps.

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Section: Local Environment Of a Hillock On A Copper Filmmentioning

confidence: 99%

Multiple twinning in cubic crystals: geometric/algebraic study and its application for the identification of the Σ3ⁿgrain boundaries

Cayron

2006

Acta Crystallogr A Found Crystallogr

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“…Their stability has been subjected to research under several aspects: thermodynamics and kinetics [1][2][3] , mass transport via surface diffusion 1,4,5 , impact of surface energy anisotropies [6][7][8][9] , fingering instabilities 7,10,11 , Ostwald ripening of islands 12 , hole pattern 13 and hillock formation [14][15][16][17][18][19] .Most of the fundamental theoretical work has been carried out by Srolovitz and Safran who developed a complete stability theory for thin films covering kinetics 20 and energetics 21 . In the case of strained layers, the shape instability leads either to equilibrium-shaped hole or to equilibrium shaped hillock formation [22][23][24] depending on the competing relaxation mechanism.…”

Section: Introductionmentioning

confidence: 99%

Hillock formation of Pt thin films on single-crystal yttria-stabilized zirconia

et al. 2012

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The stability of a metal thin films on a dielectric substrate is conditioned by the magnitude of the interactive forces at the interface. In the case of a non-reactive interface and weak adhesion, the minimization of free surface energy gives rise to an instability of the thin film. In order to study these effects, Pt thin films with a thickness of 50 nm were deposited via ion-beam sputtering on yttria stabilized zirconia single crystals. All Pt films were subjected to heat treatments up to 973 K for 2 h. The morphological evolution of Pt thin films has been investigated by means of scanning electron microscopy (SEM), atomic force microscopy (AFM) and standard image analysis techniques. Three main observations have been made: i) the deposition method has a direct impact on the morphological evolution of the film during annealing. Instead of hole formation, that is typically observed as response to a thermal treatment, anisotropic pyramidal shaped hillocks are formed on top of the film. ii) It is shown by comparing the hillocks' aspect ratio with finite element method (FEM) simulations that the hillock formation can be assigned to a stress relaxation process inside the thin film. iii) By measuring the equilibrium shapes and the shape fluctuations of the formed Pt hillocks the anisotropy of the step free energy and its stiffness have been derived in addition to the anisotropic kink energy of the hillock's edges.

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“…These elastic energy effects have also been considered in annealing experiments. 17,18 In summary, we have deposited copper films with strong ͗110͘ texture-either comparable to or stronger than the ͗111͘ texture. The microstructure characterizations indicate that a film of uniform ͗111͘ texture first forms, followed by the formation of ͗110͘ hillocks at boundaries of ͗111͘ grains; the ͗110͘ grains grow larger as the film becomes thicker.…”

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“…16 Under stress and at high temperature, hillocks of ͗110͘ texture grow at the expense of grains of ͗111͘ texture. 17,18 It is scientifically interesting and technologically important to investigate whether the ͗110͘ hillocks are also formed during deposition.In this letter, we report the development of a strong ͗110͘ texture in copper thin films, during direct current ͑dc͒ magnetron sputtering deposition. The experimental conditions are briefly summarized as follows.…”

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Development of 〈110〉 texture in copper thin films

Wei

Huang

Woo

et al. 2002

Applied Physics Letters

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Apart from the scientific interest, texture development in copper thin films is of crucial importance to their applications as interconnects or corrosion resistant coating. We report here a dominant ͗110͘ texture of copper thin films-preferred for oxidation-resistant applications-deposited by direct current magnetron sputtering. Scanning electron microscopy shows that the copper films go through a transition from ͗111͘ columns to ͗110͘ hillocks as the deposition proceeds. Cross-sectional transmission electron microscopy ͑TEM͒ indicates that the ͗110͘ grains nucleate at boundaries of ͗111͘ grains. Further, we have proposed a stress-driven nucleation and growth model of ͗110͘ grains based on the x-ray diffraction characterization and the TEM observations. © 2002 American Institute of Physics. ͓DOI: 10.1063/1.1466518͔As the dimension of integrated circuits continues to shrink, it is becoming ever more crucial to control the microstructure-in particular, the texture-of metal thin films as interconnects. Tremendous amounts of effort has been devoted to texture optimization of aluminum interconnects. [1][2][3] With increasing use of copper in place of aluminum as interconnects, development of the ͗111͘ texture in copper has been a focus in recent investigations. 4 -6 On the other hand, development of the ͗110͘ texture is also preferred in oxidation-resistant applications. 7,8 As a result, numerous investigations have focused on these two textures, ͗111͘ and ͗110͘, in copper thin films.These two textures, ͗111͘ and ͗110͘, have been observed in copper films deposited by electroplating, 9,10 cathodic vacuum arcing, 11 and dry etching. 12 The magnetron sputtering deposition-an economic approach in manufacturinghas been found to produce copper films of only weak ͗110͘ texture. 13 For face-center-cubic metals, it has been demonstrated 11,14 that incident energetic particles favor the development of ͗110͘ over the ͗111͘ texture, due to the easier channeling, and thereby less localized radiation damage in the ͗110͘ grains. When the energy of incident particles is in the range of tens of electron volts, channeling effects are absent, and the heat deposition from the kinetic energy favors the thermodynamically preferred ͗111͘ texture.Apart from the damage effects, it is known that stress may be produced in thin films by energetic particles. 11,15 Further, annealing experiments show that stress may favor the ͗110͘ texture in copper films. 16 Under stress and at high temperature, hillocks of ͗110͘ texture grow at the expense of grains of ͗111͘ texture. 17,18 It is scientifically interesting and technologically important to investigate whether the ͗110͘ hillocks are also formed during deposition.In this letter, we report the development of a strong ͗110͘ texture in copper thin films, during direct current ͑dc͒ magnetron sputtering deposition. The experimental conditions are briefly summarized as follows. The sputtering power is variable from 50 to 200 W, and the chamber is filled with 99.999% Ar, flowing into the chamber at a rat...

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Hillock formation during electromigration in Cu and Al thin films: Three-dimensional grain growth

Cited by 47 publications

References 1 publication

Multiple twinning in cubic crystals: geometric/algebraic study and its application for the identification of the Σ3ⁿgrain boundaries

Multiple twinning in cubic crystals: geometric/algebraic study and its application for the identification of the Σ3ⁿgrain boundaries

Hillock formation of Pt thin films on single-crystal yttria-stabilized zirconia

Development of 〈110〉 texture in copper thin films

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Hillock formation during electromigration in Cu and Al thin films: Three-dimensional grain growth

Cited by 47 publications

References 1 publication

Multiple twinning in cubic crystals: geometric/algebraic study and its application for the identification of the Σ3ngrain boundaries

Multiple twinning in cubic crystals: geometric/algebraic study and its application for the identification of the Σ3ngrain boundaries

Hillock formation of Pt thin films on single-crystal yttria-stabilized zirconia

Development of 〈110〉 texture in copper thin films

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Multiple twinning in cubic crystals: geometric/algebraic study and its application for the identification of the Σ3ⁿgrain boundaries

Multiple twinning in cubic crystals: geometric/algebraic study and its application for the identification of the Σ3ⁿgrain boundaries