Patent ID: 7507673

Claim:
A method for etching an object to be processed, comprising the steps of: receiving the object including an SiN portion in a processing chamber; supplying an etching gas into the processing chamber, while converting the etching gas into a plasma; and etching the SiN portion by the plasma of the etching gas, wherein the etching gas supplied into the processing chamber includes CH 2 F 2 and O 2 , the etching gas further includes Ar, a ratio of (the flow rate of Ar)/(the sum of the flow rates of CH 2 F 2 and O 2 ) in the etching gas is equal to or less than 15, a pressure in the processing chamber during etching with the etching gas is no more than 12 Pa, a flow rate of the Ar is no more than 0.3 L/min, the object includes an organic Si-based low dielectric constant film, prepared on the SiN portion, serving as an insulating film, and the SiN portion is etched by using the organic Si-based low dielectric constant film as a mask.