材料プロセス用フルオロカーボンプラズマに関する基礎研究の進展 3.親ガスおよびラジカルの気相解離過程

To investigate the mechanism of C4F8 dissociation, we made extensive measurements of electrons and radicals, as well as a theoretical study. These showed that the amount of light fluorocarbon radicals increased with increasing electron density. The dissociation of C4F8 was analyzed by using rate equations. The total dissociation rate coefficient of C4F8 was 1×10-8cm3/s, and CF2 radicals were mainly generated from products of C4F8 dissociation. F was mainly generated from CF2 by electron-impact dissociation and lost by pumping. We estimate that the C2F4 density was roughly comparable to the densities of CF and CF3, and that the surface loss probability of C2F4 increased with increasing electron density.