Process for dry etching a silicon nitride layer
AssigneeFujitsu Limited
InventorTeshiki Shin
Life of this patent
Estimating the term…
Abstract
A silicon nitride layer, particularly on a silicon dioxide layer, is dry etched successfully by using an etching gas including SF.sub.6, preferably also CH.sub.2 F.sub.2. This dry etching provides a high selectivity of etching of Si.sub.3 N.sub.4 to SiO.sub.2 and may be used for the LOCOS (local oxidation of silicon) process to reduce the width of so-called "bird beaks."
Claims10
A process for substantially selective dry etching of unmasked Si.sub.3 N.sub.4 in preference to SiO.sub.2 and a photoresist mask, wherein unmasked Si.sub.3 N.sub.4, in the presence of SiO.sub.2 and said photoresist mask are dry etched in a gas comprising SF.sub.6 and CH.sub.2 F.sub.2, mixed in a ratio between 100:8 and 100:24 at a pressure of 0.10 Torr or higher.
Dependencies are inferred from the claim text.