Applied Science and Convergence Technology 1997; 6(3): 267-274
Published online August 1, 1997
Copyright © The Korean Vacuum Society.
Ju-Hoon Lee,Young-Jun Lee,Hyeon-Soo Kim,Ju-Wook Lee,Jung-Yong Lee,Geun-Young Yeom
Silicon shallow trenches applied to the STI (Shallow Trench Isolation) of integrated circuits were etched using inductively coupled Cl₂ and HBr/Cl₂ plasmas and the effects of process parameters on the etch profiles of silicon trenches and the physical damages on the trench sidewall and bottom were investigated. The increase of inductive power and bias voltage in Cl₂ and HBr/Cl₂ plasmas increased polysilicon etch rates in general, but reduced the etch selectivities over nitride. In case of Cl₂ plasma, low inductive power and high bias voltage showed an anisotropic trench etch profile, and also the addition of oxygen or nitrogen to chlorine increased the etch anisotropy. The use of pure HBr showed a positively angled etch profile and the addition of Cl₂ to HBr improved the etch profile more anisotropically. HRTEM study showed physical defects formed on the silicon trench surfaces etched in Cl₂/N₂ or HBr/Cl₂ plasmas.