DRY ETCHING METHOD
In a dry etching method for isotropically etching each of SiGe layers selectively relative to each of Si layers in a laminated film composed of the Si layers and SiGe layers alternately and repeatedly laminated, the each of the SiGe layers is plasma-etched with pulse-modulated plasma using NF 3 gas.
1 . A dry etching method for isotropically etching each of SiGe layers selectively relative to each of Si layers in a laminated film composed of the Si layers and SiGe layers alternately and repeatedly laminated, the method comprising the step of plasma-etching each of the SiGe layers with pulse-modulated plasma using NF 3 gas.
2 . The dry etching method according to claim 1 further comprising the step of mixing the NF 3 gas with any one of O 2 gas, N 2 gas, CO 2 gas, and CO gas.
3 . A dry etching method for isotropically etching each of SiGe layers selectively relative to each of Si layers in a laminated film composed of the Si layers and SiGe layers alternately and repeatedly laminated, the method comprising the step of plasma-etching each of the SiGe layers with pulse-modulated plasma using fluorocarbon gas.
4 . The dry etching method according to claim 3 wherein the fluorocarbon gas is any one of CF 4 gas, CHF 3 gas, CH 2 F 2 gas, and CH 3 F gas.
5 . The dry etching method according to claim 4 further comprising the step of mixing the fluorocarbon gas with any one of O 2 gas, N 2 gas, CO 2 gas, and CO gas.
6 . The dry etching method according to claim 1 wherein a duty ratio of pulse-modulation is 50% or less.
7 . A dry etching method for isotropically etching each of SiGe layers selectively relative to each of Si layers in a laminated film composed of the Si layers and SiGe layers alternately and repeatedly laminated, the method comprising the step of forming a groove having a predetermined depth on the laminated film with continuous plasma and then plasma-etching each of SiGe layers with pulse-modulated plasma using NF3 gas or fluorocarbon gas.