Plasma etching apparatus

A plasma etching apparatus, comprising:

• a process chamber in which a target object to be etched is housed;
• first and second electrodes arranged a predetermined distance apart from each other and in a manner to face each other within said process chamber;
• first high frequency apply means for applying a first high frequency power having a frequency of 50 MHz or higher to said first electrode;
• second high frequency apply means for applying second and third high frequency powers to the first electrode and the second electrode, respectively, said second and third high frequency powers having a frequency not lower than 2 MHz and not higher than that of the first high frequency power, the frequency of the second high frequency power being equal to that of the third high frequency power, and the second high frequency power having a reverse phase relative to the third high frequency power;
• exhaust means for maintaining a predetermined reduced pressure within the process chamber;
• and
• gas introducing means for introducing an etching gas into the process chamber;
• wherein a plasma of the etching gas is formed by allowing said high frequency powers to form a high frequency electric field between the first and second electrodes with the target object supported on the second electrode, thereby performing an etching treatment of the target object by the plasma, and
• the thickness of the plasma sheath formed on the first electrode is increased by the second high frequency power applied from the second high frequency apply means to the first electrode.

A plasma etching apparatus, comprising:

• a process chamber in which a target object to be etched is housed;
• first and second electrodes arranged a predetermined distance apart from each other in a manner to face each other within said process chamber;
• first high frequency apply means for applying a first high frequency power having a frequency not lower than 50 MHz to said first electrode;
• second high frequency apply means for applying second and third high frequency powers to the first electrode and the second electrode respectively, said high frequency powers having a frequency not lower than 2 MHz and not higher than that of the first high frequency power, the frequency of the second high frequency power being equal to that of the third high frequency power, and the second high frequency power having a phase difference of 180±45° relative to the third high frequency power;
• exhaust means for maintaining a predetermined reduced pressure within the process chamber;
• and
• gas introducing means for introducing an etching gas into the process chamber;
• wherein a plasma of the etching gas is formed by allowing said high frequency powers to form a high frequency electric field between the first and second electrodes with the target object supported on the second electrode, thereby performing an etching treatment of the target object by the plasma, and
• the thickness of the plasma sheath formed on the first electrode is increased by the second high frequency power applied from the second high frequency apply means to the first electrode.

A plasma etching apparatus, comprising:

• a process chamber in which a target object to be processed is housed;
• exhaust means for maintaining a desired reduced pressure state within the process chamber;
• a gas introducing means for introducing an etching gas into the process chamber;
• first and second electrodes arranged a predetermined distance apart from each other to face each other within the process chamber, said target object being supported on said second electrode to face said first electrode;
• first high frequency apply means for applying a first high frequency power to the first electrode so as to cause said etching gas to form a plasma between the first electrode and the second electrode;
• second high frequency apply means for applying a second high frequency power having a frequency lower than that of the first high frequency power to the second electrode;
• third high frequency apply means for superposing a third high frequency power having a frequency lower than that of the first high frequency power and higher than that of the second high frequency power on the first high frequency power;
• and
• phase control means for adjusting the phase difference between the second high frequency power and the third high frequency power.

A plasma etching method, comprising the steps of:

• disposing a target object to be processed on a second electrode in a manner to face a first electrode with a predetermined space provided therebetween, said first and second electrodes being arranged within a process chamber having a reduced pressure;
• introducing an etching gas into said process chamber;
• applying a high frequency power having a frequency not lower than 50 MHz from a first high frequency apply means to the first electrode to cause said etching gas to generate a plasma between the first electrode and the second electrode;
• and
• applying a high frequency power from a second high frequency apply means to the second electrode;
• said second high frequency apply means also applying a high frequency power to the first electrode so as to increase the thickness of the plasma sheath formed on the first electrode.

A plasma etching method, comprising the steps of:

• disposing a target object to be processed on a second electrode in a manner to face a first electrode with a predetermined space provided therebetween, said first and second electrodes being arranged within a process chamber having a reduced pressure;
• introducing an etching gas into said process chamber;
• applying a first high frequency power to the first electrode to cause said etching gas to generate a plasma between the first electrode and the second electrode;
• applying a high frequency power having a frequency lower than that of said first high frequency power to the second electrode;
• adjusting the phase of the frequency of at least one of the first high frequency power and the second high frequency power so as to provide a predetermined phase difference between the first and second high frequency powers;
• and
• applying a third high frequency power to the first electrode such that the third high frequency power is superposed on the first high frequency power.