AVS 53rd International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS2-TuM

Paper PS2-TuM12
Modeling of Contact Hole Etching Profile in Two Geometrically Different Ways

Tuesday, November 14, 2006, 11:40 am, Room 2011

Session: Plasma Surface Interactions I: Joint AVS-AIChE Session
Presenter: H. Fukumoto, Kyoto University, Japan
Authors: H. Fukumoto, Kyoto University, Japan
K. Ono, Kyoto University, Japan
K. Eriguchi, Kyoto University, Japan
Correspondent: Click to Email
To promote the etching technique for small-diameter contact holes, it is strongly required to understand the plasma-surface interactions more precisely. We have developed the contact hole etching profile simulation based on two different geometric structural models: one is a two-dimensional axisymmetric model, and the other is a two-dimensional planar one. These models took into account the transport of particles in microstructures and surface reactions therein through sputtering, ion-assisted etching, and deposition, where the feature profile evolution was represented by the cell removal method. In the simulation, CF@sub 4@ plasmas were assumed with different plasma conditions of ion temperature, density, and energy. The behavior of ions from the plasma onto substrate surfaces was characterized by the sheath thereon, the voltage of which was in the range 50-1000 V. The simulation domain was enclosed by the sheath edge and substrate surfaces of SiO@sub 2@ with an inert etching mask having hole patterns of 20-100 nm diameter. The surface chemistry was taken to depend on the energy, angle, and flux of incident ions and neutrals. The resulting etched profile of the bottom edge was more rounded in the axismmetric model than that in the planar one. In addition, the etch rate of deep or small-diameter features was slower in the axisymmetric model than in the planar one. These results are caused by the geometric difference between the two models; in practice, more fluxes of ions and neutrals are caught on feature sidewalls in the axisymmetric model than in the planar one. The axisymmetric model, which is more realized than the planar one, showed its advantage in the contact hole etching simulation.