AVS 50th International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS+MM-MoA

Paper PS+MM-MoA9
In-Situ On-wafer Monitoring for Charge Build-up Voltage during Plasma Process

Monday, November 3, 2003, 4:40 pm, Room 315

Session: MEMS Etching
Presenter: T. Shimmura, Tohoku University, Japan
Authors: T. Shimmura, Tohoku University, Japan
S. Soda, Tohoku University, Japan
M. Koyanagi, Tohoku University, Japan
K. Hane, Tohoku University, Japan
S. Samukawa, Tohoku University, Japan
Correspondent: Click to Email
High-aspect-ratio SiO@sub 2@ contact hole etching is one of the key processes in the fabrication of ULSI devices. However, charge accumulation in contact holes during etching is one of the main causes of serious problems, such as charge-build-up damage, etching-stop, and microloading effects. Therefore, it is very important for realization of the next generation semiconductor devices to understand the mechanism of such electric charge accumulation and to be in control of plasma processes. As a result of our previous research, it was clear that deposited fluorocarbon film in contact holes shows high electric conductivity by ion irradiation.@footnote 1@ This paper reports on in-situ on-wafer monitoring for the build up charging potential during plasma processes. We were developed the device used for measuring charging potential. This device consists of Poly-Si(300 nm)/SiO2(1.7 µmm)/Poly-Si(300 nm) stacked layer structure. The contact hole of 300 nm diameter is formed to top Poly-Si layer and SiO@sub 2@ layer, and the numbers of holes were 6,400,000. The potential of top and bottom Poly-Si electrode were measured during plasma exposure with/without deposited fluorocarbon film. The potential difference between top and bottom Poly-Si electrode without the deposited fluorocarbon film is about 70 volts. On the other hand, in the case that the deposited fluorocarbon film exists on sidewall, the potential difference between top and bottom electrode was hardly observed. This result shows that the sidewall deposited fluorocarbon film has high electric conductivity and mitigates the electric charge accumulation at the contact hole bottom during SiO@sub 2@ etching processes. @FootnoteText@ @footnote 1@ T. Shimmura, S. Soda, S. Samukawa, M. Koyanagi and K. Hane, J. Vac. Sci. Technol. B, 20 2346 (2002).