AVS 50th International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS1-WeA

Paper PS1-WeA4
Angular Dependence of SiO@sub 2@, Si and Si@sub 3@N@sub 4@ Etch Yield in Fluorocarbon Gas Chemistries by using Plasma Beam

Wednesday, November 5, 2003, 3:00 pm, Room 314

Session: Mechanisms in Plasma-Surface Interactions
Presenter: K. Kurihara, ASET, Japan
Authors: K. Kurihara, ASET, Japan
A. Egami, ASET, Japan
M. Nakamura, ASET, Japan
Correspondent: Click to Email
A plasma-beam irradiation apparatus, which can control plasma parameters independently, such as ion energy, radical/ion composition and incident angle of ions, is very useful to examine the plasma-surface interactions under a real etching environment for constructing a process simulator without experiments of trial and error. We measured etch yield dependence on the incident angle of ions for Si, SiO@sub 2@, and Si@sub 3@N@sub 4@ substrates under the three conditions of Ar gas and two different fluorocarbon gas chemistries. One provides low selectivity of SiO@sub 2@ to Si using CF@sub 4@/Ar gas mixture (low selective mode), and the other provides high selectivity of that using CF@sub 4@/C@sub 4@F@sub 8@/Ar gas mixture (high selective mode). As for physical sputtering using Ar plasma, the etch yield at incident angle of 60 ° (oblique incidence) was about 4 times larger than that at incident angle of 0 ° (normal incidence) for all substrates at the ion energy of 530 eV, and this tendency was kept at the low ion energy of 120 eV. On the other hand for the case of CF@sub 4@/Ar gas chemistry, the etch yield of the oblique incidence was about 1.4 times larger than that of the normal incidence at the ion energy of 530 eV, but at that of 120 eV the etch yield did not increase with the increase in incident angle. In the case of etching reaction proceeded chemically by fluorocarbon gases, the angular dependence on the etch yield was influenced by the ion energy. The gas chemistry also affected the angular dependence on the etch yield. The etch yield of Si@sub 3@N@sub 4@ weakly depended on the incident angle in the case of the low selective mode, but that strongly depended on the incident angle in the case of the high selective mode. Concerning Si and SiO@sub 2@ substrates the angular dependence has no difference under above two modes. We will discuss the relation between composition of surface reaction layer and the etch yield. This work was funded by NEDO.