Plasma etching method for semiconductor device
View Patent ↗The present invention relates to plasma etching in which O 2 gas is added with He gas as a main component. At an early stage of a plasma discharge, Cl 2 gas is added and thereafter the supply of the Cl 2 gas is stopped. A small amount of Cl 2 gas is added in advance before the discharge start and thereafter the discharge is started.
1. A method for plasma etching a semiconductor device, comprising:
continuously supplying an etching gas composed principally of a helium gas;
initiating a discharge start;
at an early stage of the discharge start, adding a discharge ignition gas to the etching gas;
stopping a supply of the discharge ignition gas; and
after the supply of the discharge ignition gas is stopped, plasma etching the semiconductor device using the etching gas.
2. A method according to claim 1 , wherein the discharge ignition gas is selected from the group consisting of Cl 2 , CF 4 , CHF 3 , CH 2 F 2 , SF 6 and HBr.
3. A method according to claim 2 , wherein the etching gas is a mixed gas of helium and oxygen.
4. A method according to claim 2 , wherein said plasma etching is effected on a resist film formed in the semiconductor device.
5. A method for plasma etching a semiconductor device, comprising:
continuously supplying an etching gas composed principally of a helium gas;
adding a discharge ignition gas to the etching gas;
after the discharge ignition gas is added to the etching gas, initiating a discharge start;
upon commencing the discharge start, stopping a supply of the discharge ignition gas; and
after the supply of the discharge ignition gas is stopped, plasma etching the semiconductor device using the etching gas.
6. A method according to claim 5 , wherein the discharge ignition gas is selected from the group consisting of Cl 2 , CF 4 , CHF 3 , CH 2 F 2 , SF 6 and HBr.
7. A method according to claim 6 , wherein the etching gas is a mixed gas of helium and oxygen.
8. A method according to claim 6 , wherein said plasma etching is effected on a resist film formed in the semiconductor device.