FLUOROCARBON HIGH-DENSITY PLASMA .5. INFLUENCE OF ASPECT RATIO ON THEETCH RATE OF SILICON DIOXIDE IN AN ELECTRON-CYCLOTRON-RESONANCE PLASMA

Etching of high aspect ratio patterns induces a phenomenon known as re active ion etching (RIE) lag, i.e., a large feature etches faster than a smaller one. This effect is studied for oxide etched in a high dens ity plasma excited by electron cyclotron resonance using different flu orocarbon gases. The magnitude of the RIE lag is correlated with the d eposition rate of fluorocarbon film on an unbiased sample, showing tha t chemical effects are important to understand the mechanisms of RIE l ag in high density plasmas.