The role of kinetics in the nucleation and void formation in copper films produced by chemical vapor deposition

Abstract

Articles you may be interested inComparative study of the role of the nucleation stage on the final crystalline quality of (111) and (100) silicon carbide films deposited on silicon substrates.Correlation between the early stage of copper metal organic chemical vapor deposition and the material properties of thin filmThe heterogeneous nucleation and subsequent growth of chemical vapor deposited copper using hexafluoroacetylacetonate-Cu͑I͒-trimethylvinylsilane on physical vapor deposited tantalum and chemical vapor deposited titanium nitride was studied by means of electron microscopy and atomic force microscopy. It was found that the nucleation densities are about two orders of magnitude higher on TiN than on Ta. This leads to an increased roughness of films deposited on Ta compared to those produced on TiN. Moreover, the Cu films on the Ta substrate show a large number of voids, whereas no such voids were observable in the Cu films deposited on top of TiN. A simplified model for the influence of gas-surface reaction and surface self-diffusion on the shape of the Cu grains was developed. This model, which is supported by the experimental data, shows that if the grain shape changes from spherical to nonspherical before coalescence with neighboring grains, voids occur. A critical grain size and nucleation density of about 150 nm and 5ϫ10 13 m Ϫ2 , respectively, were calculated for the deposition conditions used in this work.

Nano-Scale Surface Morphology Evolution of Cu/Ti Thin Films

“…[8][9][10][11][12][13][14][15] Film thickness significantly influences the progress of agglomeration. 16 20 After the same heat-treatment, the film thickness is thinner, the agglomeration occurs easier.…”

“…1 2 In order to overcome the disadvantages of Cu such as fast diffusion into Si 3 and SiO 2 , 4 and poor adhesion to most dielectric materials, a suitable diffusion barrier/adhesion promoter is necessary. [5][6][7][8][9][10][11][12][13][14][15] However, it is observed that after high temperature annealing, copper films on some barriers may exhibit agglomeration, such as MoN, 8 TiN, 9 Ti-Si-N, 10 TiB 2 , 11 12 WC, 13 Ta, 14 ITO. 15 With the annealing temperature increasing, Cu films systems exhibit grain growth, void formation, agglomeration and chemical reaction with the Si substrate (formation of Cu 3 Si).…”

“…15 With the annealing temperature increasing, Cu films systems exhibit grain growth, void formation, agglomeration and chemical reaction with the Si substrate (formation of Cu 3 Si). [8][9][10][11][12][13][14][15] Ti can also be employed as the barrier material. However, there are lacks of investigations on agglomeration of Cu in Cu/Ti systems.…”

Process design of Cu(Sn) alloy deposition for highly reliable ultra large-scale integration interconnects

“…For 45 nm generation, deposition of a thin alloy seed layer should be deposited by conformal deposition methods such as Chemical Vapor Deposition (CVD), Atomic Layer Deposition (ALD), or Supercritical Fluid (CO 2 ) Deposition (SCFD) in which the process temperature is high enough for surface diffusion of Cu [23 -27]. To apply a Cu(Sn) alloy as the seed layer for electroplating or for filling a deep sub-micron trench, the effect of alloy elements on the morphology of Cu thin film is important for seamless and void-free deposition [23,24].…”

Nucleation of copper on TiN and SiO2 from the reaction of hexafluoroacetylacetonate copper(I) trimethylvinylsilane

“…Nucleation studies to date have shown poor wetting of Cu nuclei on air exposed TiN, where film growth proceeds via the Volmer-Weber ͑island͒ growth mode. 6,9,10 Yoen, Park, and Rhee 11 reported maximum nuclei densities (N max ) of approximately 1.7 and 2.3 ϫ10 9 cm Ϫ2 on sputtered TiN for Cu CVD at a limited set of substrate temperatures (T s ): 180 and 220°C.…”