AVS 45th International Symposium
    Plasma Science and Technology Division Wednesday Sessions
       Session PS-WeM

Paper PS-WeM4
SPORT Measured Electron Shading Effects and Comparison with Computer Simulation

Wednesday, November 4, 1998, 9:20 am, Room 318/319/320

Session: Plasma Damage
Presenter: S.C. Siu, Lam Research Corporation
Authors: S.C. Siu, Lam Research Corporation
R. Patrick, Lam Research Corporation
V. Vahedi, Lam Research Corporation
Correspondent: Click to Email
Electron shading is recognized as a major mechanism for plasma processed induced damage in commercial plasma etch chambers. As the semiconductor industry moves to smaller feature sizes and thinner gate oxides, shading induced damage becomes a greater concern. The shading effect is known to be more severe with higher aspect ratio features and high density plasmas. This study uses SPORT wafers to measure plasma parameters and the shading effect in a commercial plasma etcher. The advantage of using a SPORT wafer is that the plasma measurements are at the wafer surface. The SPORT wafer was used as a planar floating asymmetric double probe. Ion and electron currents were collected and the electron energy distribution calculated. Measurements were also done with patterned pads of different aspect ratio features. Differences in the ion and electron current were clearly seen between a bare and shaded pad. A PIC simulation was used to predict shading effects. The simulation is able to account for charged resist structures that cause electron shading. Comparisons were made between the simulation and the experimental results.