1993 Fiscal Year Final Research Report Summary
Selectivity inversion in plasma processing at low temperatures
| Project/Area Number |
04805029
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
電子材料工学
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| Research Institution | Tohoku University |
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Principal Investigator |
MATSUURA Takashi Tohoku University, Research Institute of Electrical Communication, Associate Professor, 電気通信研究所, 助教授 (60181690)
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| Co-Investigator(Kenkyū-buntansha) |
ONO Shoichi Tohoku University, Research Institute of Electrical Communication, Professor, 電気通信研究所, 教授 (00005232)
OHMI Tadahiro Tohoku University, Facultly of Engineering, Professor, 工学部, 教授 (20016463)
MUROTA Junichi Tohoku University, Research Institute of Electrical Communication, Assistant Pro, 電気通信研究所, 助教授 (70182144)
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| Project Period (FY) |
1992 – 1993
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| Keywords | ECR Plasma / Selectivity / Plasma CVD / Etching / Epitaxy / Adsorption & Reaction / Radical / Ion Irradiation |
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| Research Abstract |
Plasma processing at low temperatures becomes more and more important with advancement in ultrafine pattern device fabrication technology for silicon LSTs. The present investigators have developed ultraclean processing along with precise control of ion energy in order to realize ideal intrinsic reactions between materials and plasmas.
In this project, we studied on plasma processing at low temperatures without substrate heating, focusing on selectivity in surface adsorption and reaction, and found a selectivity inversion between deposition and etching. We also clarified that this is due to a competitive contribution of ion irradiation induced deposition and radical etching chemistry. Also, we studied on anisotropy control and plasma transport within an ultrafine spacing under highly selective condition, and clarified basic process such that anisotropic etching features are obtained at an effective ion etching yield less than 1, that the lateral etch rate of polysilicon increases linearly with carrier concentration and the vertical one shows square root dependence, and that the radical transport in overetching is described by a flow equation in the molecular flow regime. Futhermore, we achieved self-limited atomic layr etching by adsorption of reactive gas atoms without disturbance by contaminant gases as well as by alternate irradiation of low energy ions. This can be regarded as a final selective processing, because the reaction occurs only at the adsorbed site and not at the non-adsorbed site.
The success of this project supplies a key to giga-scale integration process technologies, and we continue to study the related subjects.
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