| 摘要 |
<p>PROBLEM TO BE SOLVED: To determine an etching state from the spectral intensity of FCN (fluorine cyanide), and to etch the thin-film, etc., of a silicon nitride selectively with high accuracy. SOLUTION: When a reaction gas A containing fluorocarbon or a halogen gas is changed into plasma and a substrate to be treated W comprising nitrogen atoms is etched by reactive plasma, FCN molecules in plasma are measured by an infrared absorption spectral analytic method using a light-emitting element 34 and a photo-detector 35. Plasma intensity and pressure are controlled on the basis of the density of the measured FCN molecules. Only radicals generated from plasma are forwarded into a vacuum vessel 10, and can also be applied to the case when the substrate to be treated is etched. The thin-film or base body of a silicon nitride is employed as the substrate to be treated W.</p> |
