Paper PS2-WeM4
The Characteristics of a Neutral Beam Angle using a Low Angle Reflected Neutral Beam Etching System

Wednesday, October 17, 2007, 9:00 am, Room 607

Plasma etching is one of the key technologies in the fabrication of deep submicron silicon based integrated circuits. However, plasma etching has a serious disadvantage due to the energetic charged particles such as positive ions and photons generated in the plasma which causes radiation damage causing physical defect, increased gate oxide breakdown, charging, etc. To avoid these charge-related and physical impact-related damages, several low-damage processes have been proposed. One possible alternative to avoid these problems is a low energy neutral beam etching. The neutral beams recently investigated for the anisotropic etching are generated by a low angle charge exchange collision of an ion beam in the range from 50 to 500eV (hyperthermal ions) with a flat surface. The characteristics of the neutral beam formed after the charge exchange collision such as the neutralization efficiency, neutral beam energy and its distribution, scattering angle of the neutral beam, etc. are the important in the nanoscale device etching characteristics. When an energetic ion collides with the surface, various reactions of the incident ions with the surface are occurred. The collision of ions having a high energy or a high incident angle with the surface increases the possibility of sputtering or implantation, however, the collision of ions having a low energy or a low incident angle with the surface increases the possibility of reflection. The reaction phenomena between the surface and incident ions have been mostly studied with the incident ion energy range from keV to MeV for ion implantation or surface analysis, however, the reactions phenomena with the energy range less than 1 keV, which is important in the application of neutral beam etching, have not been investigated. Therefore, in this study, the variation of angle distributions of neutral beam after the low angle reflection of the low energy (<600eV) ion beam on the flat surface were investigated using double faraday-cup and the etch characteristics for the angle distribution changes were also investigated.