Patent ID: 8641916

Claim:
A plasma etching method for forming a hole in an etching target film by using a plasma processing apparatus, which includes a vacuum evacuable processing chamber accommodating an object to be processed, a lower electrode disposed in the processing chamber and serving as a mounting table on which the object is mounted, an upper electrode disposed in the processing chamber to face the lower electrode, a processing gas supply unit for supplying a processing gas into the processing chamber, an RF power supply for applying an RF power for plasma generation to at least one of the upper electrode or the lower electrode, and a DC power supply for applying a minus DC voltage to the upper electrode, the method comprising: alternately repeating a first process and a second process, wherein in the first process a plasma is generated in the processing chamber by turning on the RF power supply and the minus DC voltage is applied to the upper electrode from the DC power supply, and in the second process the RF power supply is turned off and the minus DC voltage is applied to the upper electrode from the DC power supply, wherein, during the second process, a plasma sheath remains formed on the lower electrode by plasma generated in the first process, and wherein the method further includes reducing a thickness of the plasma sheath during the second process, and wherein an etching process is performed by positive ions in the plasma during the first process and negative ions are produced and supplied into the hole by the DC voltage to neutralize positive ions in the hole during the second process, thereby suppressing bending of travel direction of the positive ions in the hole during the etching process.