2006 Fiscal Year Final Research Report Summary
Plasma anisotropic CVD as a novel method for constructing nano-structures
| Project/Area Number |
16360020
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thin film/Surface and interfacial physical properties
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| Research Institution | KYUSHU UNIVERCITY |
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Principal Investigator |
SHIRATANI Masaharu Kyushu University, Graduate school of information science and electrical engineering, Professor, 大学院システム情報科学研究院, 教授 (90206293)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Yukio Kyushu University, Graduate school of information science and electrical engineering, Professor Emeritus, 大学院システム情報科学研究院, 名誉教授 (80037902)
KOGA Kazunori Kyushu University, Graduate school of information science and electrical engineering, Associate Researcher, 大学院システム情報科学研究院, 助手 (90315127)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Copper interconnects / Plasma CVD / Anisotropic deposition / Ion-assisted CVD / Sputtering / Nano-structure / LSI / Inductive coupled plasma |
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| Research Abstract |
We have realized anisotropic deposition of Cu, for which Cu is filled preferentially from the bottom of trenches without being deposited on their sidewall, using H-assisted plasma chemical vapor deposition (HAPCVD). The anisotropic deposition has two interesting features. One is the fact that the narrower the width of trench, the faster the deposition rate on its bottom becomes. The other is the self-limiting characteristic, that is the deposition in the trench stops automatically just after filling it completely. Such a type of deposition has a potential to overcome common problems associated with conformal filling : namely, small crystal grain size below half of the trench width, and formation of a seam with residual impurities of relatively high concentration. The key to the deposition is ion irradiation to surfaces. With increasing the flux and energy of ions, the profile changes from conformal to subconformal and then to an anisotropic one, for which Cu material is filled from the bottom of the trench without deposition on the sidewall. H_3^+ and ArH^+ are identified as the major ionic species which contribute to the control, and hence the deposition profile also depends on a ratio R=H_2/(Ar + H_2).
Moreover, mechanism of high purity Cu thin film deposition from a new F-free Cu complex, Cu(EDMDD)_2 have been studied using the HAPCVD. The species of Cu(EDMDD) is the dominant neutral radical dissociated from Cu(EDMDD)_2 by electron impact. In situ measurements by Fourier transform infrared spectroscopy show that H atoms are quite effective in removing impurities in Cu films. The simplified version of important surface reaction is Cu(EDMDD)+H _-> Cu+H(EDMDD). Cu films deposited by HAPCVD have a low as-deposited resistivity of 1.84 μΩcm and is 20 nm thick in trenches 0.5 μm wide and 2.73 μm deep.
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Research Products
(14 results)
