Study of metal barrier deposition-induced damage to porous low-k materials |
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Authors: | Larry Zhao Henny VoldersMikhail Baklanov Zsolt T?keiMarianna Pantouvaki Christopher J WilsonEls Van Besien Gerald P BeyerCor Claeys |
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Affiliation: | a IMEC, Kapeldreef 75, B-3001 Leuven, Belgium b Department of Electrical Engineering, K.U. Leuven, Belgium |
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Abstract: | A unique test structure based on a metal-insulator-semiconductor planar capacitor (Pcap) design was used to investigate several aspects of metal barrier-induced low-k damage. A special term called Effective Damage Thickness was introduced to describe the degree of damage. Ta(N) barrier was deposited on various dielectric films with porosity up to 32%. It has been found that the Effective Damage Thickness increases as the porosity increases. The damage is influenced more by the porosity of low-k films than the film density. Furthermore, the damage was modulated by Ta(N) deposition conditions. More damage was observed when higher target and/or substrate bias power was used, suggesting that the ion energy of the barrier material plays an important role in the low-k damage mechanism. A same degree of damage was observed for Ta barrier as for Ta(N), suggesting that Ta(N) deposition-induced low-k damage was primarily caused by Ta ions not nitrogen. Impact of Ru(Ta) and Cu(Mn) self forming barrier on low-k damage was also investigated. Among all the barriers studied in this work, the Ta-based barriers caused the most damage while the Cu(Mn) self forming barrier had the least damage to the low-k. The atomic masses for Ta, Ru, and Cu are 181, 101, and 64, respectively, corresponding with the observed degree of damage in the low-k material. |
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Keywords: | Porous low-k Metal barrier Damage Metal-barrier-induced damage Effective Damage Thickness |
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