Corrosion Inhibiting Effect on Copper Chemical Mechanical Planarization (CMP) in Fe(NO₃)₃ Based Slurries

Abstract:

The slurry of Copper chemical mechanical planarization for ultra large-scale integrate circuit (ULSI) usually contains oxidizer, etchant, complexing reagent and corrosive inhibitor. In planarization process, the corrosive inhibitor has an important effect on the planarization. Only if the concave surface of the wafer is properly protected from corrosion by the inhibitor, the process can obtain perfect surface planarity. In this paper, with Fe(NO3)3 as an oxidant and several corrosive inhibitors selected, the corrosive efficiency of slurries are investigated. The static etching rate and the polishing material removal rate of wafer are obtained. The electrochemical behavior of the slurry is investigated by the potentiodynamic polarization studies. And the inhibitive efficiency of the related corrosive inhibitors is calculated from the polarization data. X-ray diffraction is applied to analyze the composition modification of the copper surface. Atom force microscopy is applied to measure the surface topography of corrosive copper wafer and the value of surface roughness is measured by ZYGO surface analysis system. The result shows that the benzotriazole (BTA) is a perfect corrosive inhibitor. With addition of 0.1wt% BTA into 1.5wt% Fe(NO3)3 solution, the inhibitive efficiency can reach 99.1%. The polishing test shows that if only 1.5wt% Fe(NO3)3 is added as an oxidizer without any other additive, the surface roughness of the polished wafer is 26.9Å, while with 0.1wt%BTA added in the meantime, 5.2 Å of surface roughness can be obtained.

• Periodical: Key Engineering Materials (Volumes 291-292)
• Pages: 395-400
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.291-292.395
• Online since: August 2005
• Authors: Dong Ming Guo, X.J. Li, Zhu Ji Jin, Ren Ke Kang
• Keywords: CMP, Inhibitor, Slurry, ULSI

References

[1] D. Zeidler, Z. Stavreva, M. Plotner, K. Drescher: Characterization of Cu chemical mechanical polishing by electrochemical investigations, Microelectronic Engineering, Vol. 33 (1997), pp.259-265.

DOI: 10.1016/s0167-9317(96)00053-6

[2] Tzu-Hsuan Tsai, Yung-Fu Wu, Shi-Chern Yen: A study of copper chemical mechanical polishing in urea-hydrogen peroxide slurry by electrochemical impedance spectroscopy, Applied Surface Science, Vol. 214 (2003), pp.120-135.

DOI: 10.1016/s0169-4332(03)00272-1

[3] M. Ziomek-Moroz, A. Miller, J. Hawk, K. Cadien, D.Y. Li: An overview of corrosion-wear interaction for planarizing metallic thin films, Wear, Vol. 255 (2003), pp.869-874.

DOI: 10.1016/s0043-1648(03)00225-4

[4] Tianbao Du, Ying Luo, Vimal Desai: The combinatorial effect of complexing agent and inhibitor on chemical-mechanical planarization of copper, Microelectronic Engineering, Vol. 71 (2004)，pp.90-97.

DOI: 10.1016/j.mee.2003.08.008

[5] Y. Ein-Eli., E. Abelev, D. Starosvetsky: Electrochemical aspects of copper chemical mechanical planarization(CMP) in peroxide based slurries containing BTA and glycine, Electrochimica Acta, Vol. 49 (2004), pp.1499-1503.

DOI: 10.1016/j.electacta.2003.11.010

[6] Ronald Carpio, Janos Farkas, Rahul Jairath: Initial study on copper CMP slurry chemistries, Thin solid film, Vol. 266(1995), pp.238-244.

DOI: 10.1016/0040-6090(95)06649-7

[7] Tianbao Du, Ying Luo, Vimal Desai: The combinatorial effect of complexing agent and inhibitor on chemical-mechanical planarization of copper, Microelectronic Engineering, Vol. 71 (2004), pp.90-97.

DOI: 10.1016/j.mee.2003.08.008