Etching method and apparatus

Abstract

When a substrate is etched by using a processing gas including a first gas containing halogen and carbon and having a carbon number of two or less per molecule, while supplying the processing gas toward the substrate independently from a central and a peripheral portion of a gas supply unit, which face the central and the periphery part of the substrate respectively, the processing gas is supplied such that a gas flow rate is greater in the central portion than in the peripheral portion. When the substrate is etched by using a processing gas including a second gas containing halogen and carbon and having a carbon number of three or more per molecule, the processing gas is supplied such that a gas flow rate is greater in the peripheral portion than in the central portion.

1 . An etching method of performing etching on an etching target film of a substrate by using a processing gas including a gas containing halogen and carbon and having a carbon number of three or more per molecule, and a gas supply unit for supplying the processing gas toward the substrate from a central portion and a peripheral portion of the gas supply unit, independently, the central and the peripheral portion respectively facing the central and the periphery part of the substrate, the method comprising the step of:
 performing etching on the etching target film of the substrate while supplying the processing gas from the gas supply unit such that a flow rate of the gas per unit area of a gas supply surface of the gas supply unit is greater in the peripheral portion than in the central portion.   
   
   
       2 . The etching method of  claim 1 , wherein the step of supplying the processing gas from the gas supply unit such that a supply amount of the gas is greater in the peripheral portion than in the central portion is performed by controlling at least one of a flow rate of the gas and a dilution rate of the gas diluted with a dilution gas. 
   
   
       3 . The etching method of  claim 1 , wherein the gas is at least one of C 3 F 8  gas, C 4 F 8  gas, C 4 F 6  gas and C 5 F 8  gas. 
   
   
       4 . An etching apparatus comprising:
 a processing chamber in which a susceptor for mounting a substrate thereon is disposed;   a gas supply unit, disposed in the processing chamber to face the susceptor and having a surface facing the susceptor serving as a gas supply surface, for supplying a processing gas containing carbon and halogen toward the substrate mounted on the susceptor from a central portion and a peripheral portion of the gas supply unit, independently, the central and the peripheral portion respectively facing the central and the periphery part of the substrate;   means for controlling a pressure inside the processing chamber;   means for generating a plasma in the processing chamber;   means for controlling a flow rate of the processing gas supplied to the gas supply unit; and   a controller for controlling each of the means to perform the steps of the method described in  claim 1 ,   wherein an etching target film formed on the substrate is etched by a plasma of the processing gas.