DRY ETCHING METHOD OF ALUMINUM ALLOY FILM AND ETCHING GAS USED IN THE METHOD

摘要

The present invention relates to a dry etching method of a metal film of an Al alloy film used as a wiring material of a semiconductor integrated circuit, and provides a dry etching method corresponding to miniaturization capable of precisely etching an Al alloy film containing Si or Cu. In order to improve the manufacturing process of the semiconductor integrated circuit, in the configuration, the step of forming an alloy film (2) containing Al as a main component on the semiconductor substrate (1), and the alloy film (2) Dry-etching the alloy film 2 by a step of forming a resist pattern 4 thereon and a gas obtained by adding ammonia gas to an etching gas for etching Al by using the resist pattern 4 as a mask. In the dry etching method of the Al alloy film 2 formed in the step, the flow rate of the ammonia gas is not less than 1/2 of the flow rate of the etching gas and is less than or equal to the flow rate of the etching gas. Thereby, also in the case of the Al alloy film containing Si and Cu, an Al alloy film can be dry-etched in a fine pattern, suppressing a microloading effect, without generating an etching residue.