PLASMA PROCESSING APPARATUS AND PLASMA PROCESSING METHDO

1 . A plasma processing apparatus, comprising:

a chamber;

an introducing part configured to introduce a process gas into the chamber;

a substrate electrode disposed in the chamber and configured to mount a substrate directly or indirectly thereon, the substrate electrode including a plurality of first and a plurality of second electrode elements alternately arranged;

a high-frequency power source configured to output a high-frequency voltage of 40 MHz or more for ionizing the process gas to generate plasma;

a low-frequency power source configured to output a low-frequency voltage of 20 MHz or less for introducing ions from the plasma; and

a switching mechanism configured to apply the low-frequency voltage alternately to the first and the second electrode elements.

2 . The plasma processing apparatus of claim 1 ,

wherein the switching mechanism applies a voltage in which the low-frequency voltage and the high-frequency voltage are superposed, alternately to the first and the second electrode elements.

3 . The plasma processing apparatus of claim 1 , further comprising a counter electrode facing the substrate electrode,

wherein the high-frequency voltage is applied to the counter electrode.

4 . The plasma processing apparatus of claim 1 ,

wherein the substrate electrode further includes a plurality of third electrode elements disposed between the first and the second electrode elements; and

wherein the plasma processing apparatus further comprises a second high-frequency power source configured to apply a second high-frequency voltage for stabilizing the plasma to the third electrode elements.

5 . The plasma processing apparatus of claim 1 ,

wherein the substrate electrode includes a plurality of dielectric members disposed at least between the first and the second electrode elements.

6 . The plasma processing apparatus of claim 5 ,

wherein dielectric constants of the dielectric members are 7 or more.

7 . The plasma processing apparatus of claim 5 ,

wherein the dielectric members have plate shapes; and

wherein the first and the second electrode elements include a plurality of conductive layers disposed on the dielectric members.

8 . The plasma processing apparatus of claim 1 ,

wherein widths of the first and the second electrode elements are not less than 1 mm nor more than 5 mm; and

wherein intervals between the first and the second electrode elements are not less than 1 mm nor more than 5 mm.

9 . The plasma processing apparatus of claim 1 ,

wherein the switching mechanism includes:

a first switch configured to switch a connection state between the first electrode elements and the low-frequency power source;

a second switch configured to switch a connection state between the second electrode elements and the low-frequency power source; and

a switch controller configured to control the first and the second switch.

10 . The plasma processing apparatus of claim 9 ,

wherein the switch controller controls the first and the second switch so as to connect ones of the first and the second electrode elements to a ground when the others of the first and the second electrode elements are connected to the low-frequency power source.

11 . The plasma processing apparatus of claim 9 ,

wherein the switch controller configured to control the first and the second switch so as to repeat a first to a fourth state in sequence,

the first state being defined by the first electrode elements connected to the low-frequency power source, and the second electrode elements not connected to the low-frequency power source;

the second state being defined by both of the first and the second electrode elements connected to the low-frequency power source;

the third state being defined by the first electrode elements not connected to the low-frequency power source, and the second electrode elements connected to the low-frequency power source; and

the fourth state being defined by both of the first and the second electrode elements connected to the low-frequency power source.

12 . The plasma processing apparatus of claim 1 ,

wherein the substrate electrode includes a plurality of electrode elements arranged in lines in two directions; and

wherein the plasma processing apparatus further comprises a selecting mechanism configured to select the first and the second electrode elements from the plurality of electrode elements.

13 . The plasma processing apparatus of claim 12 ,

wherein the selecting mechanism repeatedly selects the first and the second electrode elements so as to rotate directions of arranging the first and the second electrode elements.

14 . The plasma processing apparatus of claim 1 ,

wherein the switching mechanism switches a first and a second state in accordance with a progress of processing, the first state being defined by the low-frequency voltage applied alternately to the first and the second electrode elements, the second state being defined by the low-frequency voltage applied to both of the first and the second electrode elements.

15 . The plasma processing apparatus of claim 1 ,

wherein the switching mechanism changes a period of alternately application of the low-frequency voltage to the first and the second electrode elements in accordance with a progress of processing.

16 . The plasma processing apparatus of claim 1 , further comprising a rotating mechanism configured to relatively rotate between the substrate and the substrate electrode.

17 . The plasma processing apparatus of claim 16 ,

wherein a period T of switching the first and the second electrode elements is not 0.5n times a period Tr of the rotation, where n: integer.

18 . (canceled)