Copper Transport in Thermal SiO2

Shacham‐Diamand, Yosi; Dedhia, A.; Hoffstetter, D.; Oldham, W.G.

doi:10.1149/1.2220837

Cited by 245 publications

(116 citation statements)

References 4 publications

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“…There are two main reasons why Ti improves Cu adhesion in this case. First, there are two new interfaces that are formed, which are stronger than the original SiO 2 /Cu one [16]. Second, being in its initial stage of island growth, the Ti film has higher surface roughness than SiO 2 (which simply increases the contact area between Ti and Cu).…”

Section: Ti Underlayermentioning

confidence: 99%

Quantitative Modeling and Measurement of Copper Thin Film Adhesion

et al. 1998

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Numerous mechanisms have been identified as fundamental to the adhesion of thin metallic films. The primary mechanism is the thermodynamic work of adhesion of the interface, which in its most basic description is the difference between the surface energies of the two materials and that of the interface. This quantity is often described as leveraging the contributions of other mechanisms. One of the more important mechanisms is that of plasticity occurring in a process zone in the vicinity of the delamination boundary. A quantitative model to characterize the contributions of plastic energy dissipation has been developed and used to rationalize experimental adhesion assessments. This model incorporates the functional dependence of the film thickness and constitutive properties. Orders of magnitude increases in the practical work of adhesion were both observed and predicted. Experimentally, the films used for model comparison were sputter-deposited copper ranging from 40 to 3300 nm in thickness, with and without a thin 10 nm Ti underlayer. Nanoindentation induced delamination of the Cu from SiO 2 /Si wafers were evaluated in the context of composite laminate theory to determine adhesion energies ranging from 0.6 to 100 J/m 2 for bare Cu and from 4 to 110 J/m 2 for Cu with the Ti underlayer.

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Section: Ti Underlayermentioning

confidence: 99%

Quantitative Modeling and Measurement of Copper Thin Film Adhesion

et al. 1998

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“…7,10 In general, this may be contributed to a higher diffusion coefficient of oxidized Cu in the amorphous matrix of SiO 2 thin films as well as electrical field enhanced diffusion. A potential nano porous structure of our SiO 2 thin film may also increase Cu zþ mobility.…”

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confidence: 99%

Redox processes in silicon dioxide thin films using copper microelectrodes

Tappertzhofen¹,

Menzel²,

Valov³

et al. 2011

Applied Physics Letters

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Although SiO2 is a typical insulator, we demonstrate an electrochemical characteristic of the Cu/Cu+ oxidation at the interface with 30 nm thick silicon dioxide thin films studied by cyclic voltammetry. This study reveals the process of anodic oxidation and subsequent reduction of oxidized Cu ions injected in the SiO2 layer with special attention to the kinetics of the redox process. We estimated the diffusion coefficient and the mobility of Cu ions in SiO2. The results gain deeper insight in the processes involved during resistive switching of Cu/SiO2 based nonvolatile memory devices.

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“…At present, Cu has attracted more attention as a new interconnection metallization material, because of its low resistivity (1.67 µΩ cm for bulk), and high reliability against electromigration (EM) [1,2]. However, Cu is regarded as a fatal impurity in the semiconductor fabrication process due to its high diffusivity in Si (diffusion coefficient ≈ 10 −8 cm 2 /s at room temperature) [3][4][5]. Therefore, a thin diffusion barrier preventing Cu diffusion in Si substrate is needed in order to successfully integrate Cu as an interconnecting layer.…”

mentioning

confidence: 99%

Grain boundary diffusion of Cu in TiN film by X-ray photoelectron spectroscopy

Lim

Lee

Chung

et al. 2000

Applied Physics A: Materials Science & Processing

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In this study, the grain boundary diffusion of Cu through a TiN layer with columnar structure was investigated by X-ray photoelectron spectroscopy (XPS). It was observed that Cu atoms diffuse from the Cu layer to the surface along the grain boundaries in the TiN layer at elevated temperature. In order to estimate the grain boundary diffusion constants, we used the surface accumulation method. The diffusivity of Cu through TiN layer with columnar structure from 400The present semiconductor devices such as ULSI require the higher integration density with smaller submicron design scheme. However, aluminum and aluminum-based metallization have some problems such as the relatively higher resistance and the failure caused by the electromigration. At present, Cu has attracted more attention as a new interconnection metallization material, because of its low resistivity (1.67 µΩ cm for bulk), and high reliability against electromigration (EM) [1,2]. However, Cu is regarded as a fatal impurity in the semiconductor fabrication process due to its high diffusivity in Si (diffusion coefficient ≈ 10 −8 cm 2 /s at room temperature) [3][4][5]. Therefore, a thin diffusion barrier preventing Cu diffusion in Si substrate is needed in order to successfully integrate Cu as an interconnecting layer.TiN is one of the most widely investigated barrier materials in Cu metallization, as well as in Al-based metallization. Thus, there are many reports for the Cu diffusion in TiN during the annealing even though the failure temperatures of TiN against Cu diffusion differ among researchers [6-10]. Generally, it was known that the grain boundaries of TiN film act as a main diffusion path of Cu or Si [8]. Therefore, to understand the temperature failure mechanisms of TiN against Cu, an investigation of the diffusivity and diffusion mechanisms of Cu in TiN thin film are needed.From the results of Chamberlain [11], the grain boundary diffusivity (D b ) and the activation energy (Q b ) of Cu in the Cu/TiN/sapphire system were 10 −17 -10 −19 cm 2 /s and 4.4 eV, respectively, at temperature region from 600 • C to 700 • C. His results indicate that TiN in Cu metallization is a better barrier system than that in Al metallization since Q b and D b of Al through TiN layer were 0.31 eV and ≈ 10 −16 cm 2 /s, respectively, from 300 • C to 550 • C [12]. Although the differences in failure temperatures and diffusion coefficients are caused by various film microstructures and characterization methods, the grain boundary diffusion coefficients of Chamberlain [11], are too different from those of Al through TiN layer. In general, the value of Q b is approximately half of that for lattice diffusion [13] and in the range of T < 1 3 T m , the smaller the measurement temperature T is, the smaller the value of Q b should be [14]. Therefore, his values of diffusion coefficient seem to be unreasonable from a view point of the grain boundary diffusion. In fact, his Q b , 4.4 eV, for Cu in TiN layer is closed to the value of the bulk (=lattice) diffusion.To study this gr...

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Copper Transport in Thermal SiO2

Cited by 245 publications

References 4 publications

Quantitative Modeling and Measurement of Copper Thin Film Adhesion

Quantitative Modeling and Measurement of Copper Thin Film Adhesion

Redox processes in silicon dioxide thin films using copper microelectrodes

Grain boundary diffusion of Cu in TiN film by X-ray photoelectron spectroscopy

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