Oxide film etching method

A method of etching an oxide film, which uses a RIE (Reactive Ion Etching) mechanism in which a process chamber can maintain a vacuum, a high-frequency electric filed is generated between a pair of opposing electrodes and high-frequency power is supplied to one of the electrodes, which holds an object, and in which the object with the oxide film formed on an upper surface is held, a plasma is generated in an atmosphere of an etching gas introduced into the process chamber, the oxide film formed on the object is etched in the plasma, and RIE is performed in the following conditions:

• C4F6 and O2 are applied at a total flow rate of 0.01 to 0.04 L/min;
• C4F6 is applied in a ratio of 1.0 to 1.5 with respect to O2;
• a gas pressure of 1.3 to 26 Pa (10 to 200 mTorr) is maintained in the process chamber ranges during the etching;
• and
• the plasma has a density of at least 3×1010/cm3, not exceeding 1×1011/cm3, during the etching.

A method of etching an oxide film, which uses a mechanism in which a high frequency electric filed is applied between opposing two electrodes provided in a process chamber maintained in a vacuum, thereby to supply high frequency power to both electrodes to generate a plasma, a high-frequency electric filed is generated between a pair of opposing electrodes and high-frequency power is supplied to both electrodes an object, and in which the object with the oxide film formed on an upper surface is held, a plasma is generated in an atmosphere of an etching gas introduced into the process chamber, the oxide film formed on the object is etched in the plasma, and RIE is performed in the following conditions:

• C4F6 and O2 are applied at a total flow rate of 0.03 to 0.1 L/min;
• C4F6 is applied in a ratio of 0.7 to 1.1 with respect to O2;
• a gas pressure of 1.33 to 9.97 Pa (10 to 75 mTorr) is maintained in the process chamber ranges during the etching;
• and
• the plasma has a density of at least 5×1010/cm3, not exceeding 2×1011/cm3, during the etching.