Stage having electrostatic chuck and plasma processing apparatus using same

• US 5,460,684 A
• Filed: 12/03/1993
• Issued: 10/24/1995
• Est. Priority Date: 12/04/1992
• Status: Expired due to Term

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Kondo, Masaki, Masuoka, Noboru, Saeki, Hiroaki, Asakawa, Teruo
• Primary Examiner(s): Kunemund, Robert
• Assistant Examiner(s): MCDONALD, RODNEY GLENN
• Application Number:
  US08/160,842
• Time in Patent Office: 690 Days
• Field of Search: 156/345, 156/643, 118/724, 118/725, 118/728, 118/723 MW, 118/723 ME, 118/723 MR, 118/723 MA, 118/723 E, 118/723 ER, 118/723 I, 118/723 IR, 118/723 R, 204/298.15, 204/298.31, 204/298.34
• US Class Current: 156/345.51
• CPC Class Codes: C23C 16/4586 Elements in the interior of the support, e.g. electrodes, heating or cooling devices
• CPC Class Codes: H01L 21/6831 using electrostatic chucks
• CPC Class Codes: H01L 21/6833 Details of electrostatic chucks

Abstract

The plasma etching apparatus for a semiconductor wafer includes a susceptor provided in the vacuum process chamber. An electrostatic chuck for attracting and holding the wafer is provided on the susceptor. The electrostatic chuck comprises a chuck electrode provided on the susceptor via an insulative layer. The chuck electrode is connected to the positive terminal of the DC power supply via a switch. The chuck electrode is coated with a resistive layer, and the wafer is placed directly on the resistive layer. The resistive layer exhibits an electric resistivity of 1×10¹⁰ Ω·cm to 1×10¹² Ω·cm in a temperature range for etching. The resistive layer is formed to have such a surface roughness that a center line average hight falls within a range of 0.1 to 1.5 μm. When the potential of the positive terminal of the DC power supply is applied to the chuck electrode, and the wafer is grounded via plasma, a contact potential difference is created between the surface of the resistive layer and the rear surface of the wafer, generating an electrostatic attractive force, so that the wafer is attracted and held by the resistive layer.

Claims

1. A plasma processing apparatus for processing a substrate having a main surface to be processed, and a rear surface opposite to said main surface, by use of plasma of a process gas, while attracting and holding said substrate on a stage having an electrostatic chuck by an electrostatic attractive force, comprising:

(a) a process chamber for enclosing said substrate;

(b) means for supplying said process gas to said process chamber;

(c) means for evacuating said process chamber and creating a vacuum state;

(d) means for making said process gas into plasma in said process chamber; and

(e) said stage provided in said process chamber, said stage comprising;

a main body having a supporting surface for supporting said substrate via said rear surface thereof;

the electrostatic chuck having a first electrode and a second electrode, said first and second electrodes of said electrostatic chuck arranged to face said supporting surface, said first and second electrodes being insulated from each other;

first power supply means for selectively applying a first potential to said first and second electrodes;

second power supply means for selectively applying a second potential different from said first potential to said second electrode;

switch means for selectively connecting said first and second electrodes; and

first and second resistive layers for covering said first and second electrodes, respectively, said first and second resistive layers being insulated from each other, each having a surface brought into contact with said rear surface of said substrate when said substrate is supported by said supporting surface, and each exhibiting an electric resistivity of 1×

10¹⁰ Ω

·

cm to 1×

10¹² Ω

·

cm in a temperature range when attracting and holding said substrate,

wherein while said first and second potentials are applied to said first and second electrodes, respectively, a closed loop from said first power supply means via said substrate to said second power supply means is formed, a contact potential difference is created between said surface of each of said first and second resistive layers and said rear surface of said substrate, and said substrate is attracted and held by said first and second resistive layers, and

while said first potential is applied to said first and second electrodes, and a third potential different from said first potential is applied to said substrate via said plasma, a contact potential difference is created between said surface of each of said first and second resistive layers and said rear surface of said substrate, and said substrate is attracted and held by said first and second resistive layers;

the apparatus further including control means for controlling said first and second power supply means such that said first potential is applied to said first and second electrodes when plasma is generated in said process chamber.

2. An apparatus according to claim 1, wherein said surface of each of said first and second resistive layers is formed to have such a surface roughness that a center line average height falls within a range of 0.1 to 1.5 μ

m.

3. An apparatus according to claim 1, wherein said temperature range is set within -50°

C. to 120°

C., and each of said first and second resistive layers is formed of a material selected from the group consisting of SiC and Al₂ O₃ containing conductive impurities adjusted.

4. An apparatus according to claim 1, wherein said supporting surface comprises a surface for supporting a semiconductor wafer.

5. A plasma processing apparatus for processing a substrate having a main surface to be processed, and a rear surface opposite to said main surface, by use of plasma of a process gas, while attracting and holding said substrate on a stage having an electrostatic chuck by an electrostatic attractive force, comprising:

(a) a process chamber for enclosing said substrate;

(b) means for supplying said process gas to said process chamber;

(c) means for evacuating said process chamber and creating a vacuum state;

(d) means for making said process gas into plasma in said process chamber; and

(e) said stage provided in said process chamber, said stage comprising;

a main body having a supporting surface for supporting said substrate via said rear surface thereof,

first and second electrodes for attracting said substrate, arranged in said main body to face said supporting surface, said first and second electrodes being insulated from each other,

first power supply means for selectively applying a first potential to said first and second electrodes,

second power supply means for selectively applying a second potential, different from said first potential, to said second electrode, and

switch means for selectively connecting said first and second electrodes,

wherein said first and second potentials are applied to said first and second electrodes, respectively, from said first and second power supply means so as to attract and hold said substrate on said stage, while no plasma is generated in said process chamber, and

said first potential is applied to both of said first and second electrodes from said first power supply means and a third potential different from said first potential is applied to said substrate via said plasma so as to attract and hold said substrate on said stage, while said plasma is generated in said process chamber;

the apparatus further including control means for controlling said first and second power supply means such that said first potential is applied to said first and second electrodes when plasma is generated in said process chamber.

6. The apparatus according to claim 5, further comprising first and second resistive layers for covering said first and second electrodes, respectively, each having a surface facing said rear surface of said substrate when said substrate is supported by said supporting surface.

7. The apparatus according to claim 6, wherein said first and second resistive layers each exhibit an electric resistivity of 1×

10¹⁰ Ω

·

cm to 1×

10¹² Ω

·

cm in a temperature range when attracting and holding said substrate, and are electrically insulated from each other.

8. The apparatus according to claim 7, wherein said temperature range is set within -50°

C. to 120°

C., and said resistive layer is formed of a material selected from the group consisting of SiC, and Al₂ O₃ containing conductive impurities.

9. The apparatus according to claim 7, wherein said temperature range is set within 300°

C. to 600°

C., and said resistive layer is formed of a material selected from the group consisting of pyrolytic boron nitride, Si₃ N₄, and Al₂ O₃ containing conductive impurities.

10. The apparatus according to claim 5, wherein said supporting surface comprises a surface for supporting a semiconductor wafer.

11. The apparatus according to claim 5, wherein said process gas comprises an etching gas.

12. The apparatus according to claim 6, wherein said surface of each of said first and second resistive layers is formed to have a surface roughness such that a center line average height falls within a range of 0.1 to 1.5 μ

m, and is brought into direct contact with said rear surface of said substrate.

13. The apparatus according to claim 6, wherein said surface of said resistive layer is coated with a coating of an insulating material, and a thickness of said coating is 1 μ

m or less.