Patent ID: 7842190

Claim:
A plasma etching method for performing an etching on a target object having a lower organic material film, an intermediate layer formed of an inorganic material and an upper organic material film, which are formed on a base layer in that order, the intermediate layer and the upper organic material film being patterned, the method comprising the steps of: etching the lower organic material film by using the upper organic material film and the intermediate layer as a mask in a processing chamber of a plasma etching apparatus, while using an etching gas made up of a gaseous mixture including an O 2 gas and a CO gas, to thereby transfer a pattern of the intermediate layer to the lower organic material film, wherein a ratio of a flow rate of the CO gas to a total flow rate of the etching gas ranges from about 40 to 99%; and etching the base layer including SiO 2 by using the lower organic material film and the intermediate layer as a mask.