Electrostatic chuck

1. An electrostatic chuck comprising:

a disk-shaped ceramic plate having a wafer placement surface on a surface thereof;

an electrostatic electrode embedded in the ceramic plate; and

gas grooves that are divided in a plurality of zones when the ceramic plate is seen from above and each of which is independently provided in the wafer placement surface so as to extend from one to the other of a pair of gas supply/discharge openings for a corresponding one of the zones,

wherein a pattern in which a gas is supplied to each of the gas grooves provided for a corresponding one of the zones is selectable between a first pattern in which the gas flows from one to the other of the pair of gas supply/discharge openings and a second pattern in which the gas flows from the other to the one of the pair of gas supply/discharge openings.

2. The electrostatic chuck according to claim 1 ,

wherein the plurality of zones include two or more annular zones that are concentric with the ceramic plate and that are provided outside of a circular protrusion that is concentric with the ceramic plate.

3. The electrostatic chuck according to claim 2 ,

wherein the pairs of gas supply/discharge openings each of which is provided for a corresponding one of the gas grooves are arranged in a predetermined radial direction of the ceramic plate, and a direction of a gas that flows through one of two gas grooves that are provided in adjacent zones is set to be clockwise and a direction of a gas that flows through the other of the two gas grooves is set to be counterclockwise.

4. The electrostatic chuck according to claim 1 ,

wherein the plurality of zones are a plurality of sectoral zones that are separated by radii of the ceramic plate.

5. The electrostatic chuck according to claim 1 ,

wherein the plurality of zones are a plurality of curved zones that are separated by curves that extend from a center toward an outer edge of the ceramic plate.

6. The electrostatic chuck according to claim 1 ,

wherein the gas grooves each of which is provided for a corresponding one of the zones are respectively capable of being supplied with gases that differ in characteristics.

7. The electrostatic chuck according to claim 1 , comprising:

a resistance heating element that is embedded in the ceramic plate so as to extend from one to the other of a pair of terminals for each of the zones.

8. An electrostatic chuck comprising:

a disk-shaped ceramic plate having a wafer placement surface on a surface thereof;

an electrostatic electrode embedded in the ceramic plate; and

gas grooves that are divided in a plurality of zones when the ceramic plate is seen from above and each of which is independently provided in the wafer placement surface so as to extend from one to the other of a pair of gas supply/discharge openings for a corresponding one of the zones,

wherein the plurality of zones include two or more annular zones that are concentric with the ceramic plate and that are provided outside of a circular protrusion that is concentric with the ceramic plate, and

wherein the pairs of gas supply/discharge openings each of which is provided for a corresponding one of the gas grooves are arranged in a predetermined radial direction of the ceramic plate, and a direction of a gas that flows through one of two gas grooves that are provided in adjacent zones is set to be clockwise and a direction of a gas that flows through the other of the two gas grooves is set to be counterclockwise.

9. The electrostatic chuck according to claim 8 ,

wherein the gas grooves each of which is provided for a corresponding one of the zones are respectively capable of being supplied with gases that differ in characteristics.

10. The electrostatic chuck according to claim 8 , comprising:

a resistance heating element that is embedded in the ceramic plate so as to extend from one to the other of a pair of terminals for each of the zones.