AVS 49th International Symposium
    Plasma Science Tuesday Sessions
       Session PS-TuP

Paper PS-TuP31
Study on the Characteristics of Neutral Species in the Low Angle Forward Reflected Neutral Beam Etching System

Tuesday, November 5, 2002, 5:30 pm, Room Exhibit Hall B2

Session: Plasma Applications
Presenter: M.J. Chung, Sungkyunkwan University, Korea
Authors: M.J. Chung, Sungkyunkwan University, Korea
D.H. Lee, Sungkyunkwan University, Korea
N.G. Cho, Sungkyunkwan University, Korea
G.Y. Yeom, Sungkyunkwan University, Korea
Correspondent: Click to Email
submicron semiconductor devices as well as future nanoscale devices. To avoid the charge-related damage, several low-damage processes have been proposed and one of the techniques to avoid the problem is to use neutral beam etching. One of the techniques fabricating a neutral beam is to use a low angle reflection of the ion beam where ions extracted from the ion source are neutralized by a low angle reflection during the reflection. Previous study showed that, by the reflection of the ion beam at 5 degree angle of incidence, most all of the ions could be neutralized. The degree of neutralization was similar to the all of the gases used in the experiment such as SF@sub 6@, NF@sub 3@ and CF@sub 4@ which can be used for the etching of SiO@sub 2@ and Si. Also, using radical beams from these gases, nearly vertical SiO@sub 2@ etching could be obtained. Even though the ions reflected at the reflector were proven to be neutralized, the energy distribution of these reflected neutrals and the possibility of cracking after reflection for reactive gases such as SF@sub 6@, NF@sub 3@, and CF@sub 4@ need to be investigated. In this study, energy and species of neutrals generated by the low angle forward reflection of reactive ions were analyzed by means of direct sampling using a quadrupole mass spectrometer (QMS) with double ion energy analyzers modified to detect neutral energy and species. Using this modified mass spectrometer, the concentration and energy distribution of each neutral species were investigated as a function of rf power, gas flow rate, and acceleration/extraction voltage of the ion gun for various reactive gases. The correlation of the etch characteristics of SiO@sub 2@ and Si with the characteristics of the measured incident neutral species were investigated to study the etch mechanism of Si and SiO@sub 2@ using the low angle reflection technique.