Electrostatic chucking method and substrate processing apparatus

• US 10,269,607 B2
• Filed: 12/18/2015
• Issued: 04/23/2019
• Est. Priority Date: 12/25/2014
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Sasaki, Yasuharu, Tomioka, Taketoshi, Kishi, Hiroki, Suh, Jisoo
• Primary Examiner(s): Tran, Thienvu V
• Assistant Examiner(s): Thomas, Lucy M
• Application Number:
  US14/975,377
• Publication Number:
  US 20160189994A1
• Time in Patent Office: 1,222 Days
• Field of Search: 361234
• CPC Class Codes: H01L 21/67109 mainly by convection
• CPC Class Codes: H01L 21/6833 Details of electrostatic chucks
• CPC Class Codes: H02N 13/00 Clutches or holding devices using electrostatic attraction, e.g. using Johnson-Rahbek effect

Abstract

An electrostatic chucking method uses a substrate processing apparatus including an electrostatic chuck, a focus ring, a supply unit configured to supply a heat transfer medium to a space formed between the focus ring and the electrostatic chuck, and a plurality of electrodes provided at a region in the electrostatic chuck which corresponds to the focus ring. The electrostatic chucking method includes supplying by the supply unit the heat transfer medium to the space for a plasma processing period for which a plasma for processing the substrate is generated, and applying different voltages to the plurality of electrodes to attract and hold the focus ring on the electrostatic chuck for a period other than the plasma processing period.

Claims

1. An electrostatic chucking method using a substrate processing apparatus including:

an electrostatic chuck on which a substrate is mounted;

a focus ring provided on the electrostatic chuck to surround a region where the substrate is mounted;

a supply unit configured to supply a heat transfer medium to a space formed between the focus ring and the electrostatic chuck; and

a plurality of electrodes provided in the electrostatic chuck, the method comprising;

supplying by the supply unit the heat transfer medium to the space for a plasma processing period for which a plasma for processing the substrate is generated; and

applying different voltages to the plurality of electrodes to attract and hold the focus ring on the electrostatic chuck for a period other than the plasma processing period,

wherein the focus ring includes a bottom surface extending continuously from an outer periphery of the bottom surface to an inner periphery of the bottom surface and the plurality of electrodes are disposed below the bottom surface of the focus ring such that each electrode from the plurality of electrodes is partially overlapped or entirely overlapped by the bottom surface of the focus ring with respect to a top view of the focus ring.

2. The electrostatic chucking method of claim 1, wherein said applying different voltages to the plurality of electrodes comprises applying the different voltages such that a potential difference is generated between the electrodes.

3. The electrostatic chucking method of claim 1, wherein the plurality of electrodes are provided to correspond to an inner peripheral side of the focus ring and an outer peripheral side of the focus ring, and

wherein said applying different voltages to the plurality of electrodes comprises applying voltages of a first polarity to the electrodes provided to correspond to the inner peripheral side of the focus ring and voltages of a second polarity opposite to the first polarity to the electrodes provided to correspond to the outer peripheral side of the focus ring.

4. The electrostatic chucking method of claim 1, wherein said applying different voltages to the plurality of electrodes comprises applying the different voltages to the plurality of electrodes under a weak plasma processing condition in which a high frequency power ranging from 0 W to 2000 W is applied for plasma generation.

5. The electrostatic chucking method of claim 1, including applying voltages of the same polarity to the plurality of electrodes for the plasma processing period.

6. The electrostatic chucking method of claim 1, including applying a same voltage to each of the plurality of electrodes for the plasma processing period.

7. The electrostatic chucking method according to claim 1, wherein in addition to the plurality of electrodes the electrostatic chuck further includes a center electrode located radially inside of the plurality of electrodes, the method further comprising:

applying a voltage to said center electrode during the plasma processing period; and

applying no voltage to the center electrode during the period other than the plasma processing period.

8. The electrostatic chucking method according to claim 7, wherein the substrate processing apparatus includes a processing chamber, and

wherein the period other than the plasma processing period during which different voltages are applied to the plurality of electrodes to attract and hold the focus ring on the electrostatic chuck includes at least one of a substrate loading period during which a substrate is loaded into the processing chamber or a substrate unloading period during which a substrate is unloaded from the processing chamber.

9. The electrostatic chucking method according to claim 8, wherein the period other than the plasma processing period comprises both the substrate loading period and the substrate unloading period and wherein the period other than the plasma processing period further includes a cleaning period, and wherein the method further comprises:

supplying the heat transfer medium to the space between the focus ring and the electrostatic chuck during the plasma processing period,

not supplying the heat transfer medium to the space during the substrate loading period and the substrate unloading period; and

supplying the heat transfer medium to the space during the cleaning period.

10. The electrostatic chucking method according to claim 1, wherein in addition to the plurality of electrodes, the electrostatic chuck further includes a center electrode located radially inside of the plurality of electrodes, the method further comprising:

applying a voltage to said center electrode and applying a voltage to at least one of the plurality of electrodes during the plasma processing period;

applying no voltage to the center electrode during the period other than the plasma processing period; and

applying at least two different non-zero voltages to the plurality of electrodes during the period other than the plasma processing period.

11. A substrate processing apparatus comprising:

an electrostatic chuck on which a substrate is mounted;

a focus ring provided on the electrostatic chuck to surround a region where the substrate is mounted, wherein the focus ring includes a bottom surface extending continuously from an outer periphery of the bottom surface to an inner periphery of the bottom surface;

a supply unit configured to supply a heat transfer medium to a space formed between the focus ring and the electrostatic chuck;

a plurality of electrodes provided in the electrostatic chuck and disposed below the bottom surface of the focus ring such that each electrode from the plurality of electrodes is partially overlapped or entirely overlapped by the bottom surface of the focus ring with respect to a top view of the focus ring; and

a control unit configured to control a supply of the heat transfer medium by the supply unit to the space for a plasma processing period for which a plasma for processing the substrate is generated and to control an application of different voltages to the plurality of electrodes to attract and hold the focus ring on the electrostatic chuck for a period other than the plasma processing period.

12. The substrate processing apparatus of claim 11 wherein the apparatus further includes a center electrode positioned radially inside of the plurality of electrodes, and wherein the control unit is configured to control application of voltages to the center electrode and the plurality of electrodes such that:

a voltage is applied to the center electrode during the plasma processing period;

a voltage is applied to at least one of the plurality of electrodes during the plasma processing period;

no voltage is applied to the center electrode during the period other than the plasma processing period, and at least two different non-zero voltages are applied to the plurality of electrodes during the period other than the plasma processing period.

13. The substrate processing apparatus of claim 12, wherein the control unit is configured to control application of voltages of different polarities to the plurality of electrodes during the period other than the plasma processing period.

14. The substrate processing apparatus of claim 12, wherein the control unit is configured to control application of a same voltage to each of the plurality of electrodes during the plasma processing period.

15. A substrate processing apparatus comprising:

an electrostatic chuck on which a substrate is mounted;

a focus ring provided on the electrostatic chuck to surround the substrate, wherein the focus ring includes a bottom surface extending continuously from an outer periphery of the bottom surface to an inner periphery of the bottom surface;

an inner electrode and an outer electrode provided circumferentially under the bottom surface of the focus ring such that with respect to a top view of the focus ring the inner electrode and the outer electrode are each partially overlapped or entirely overlapped by the bottom surface of the focus ring;

one or more DC power supply to supply DC voltage to the inner electrode and/or the outer electrode, and

a control unit configured to control an application of a first DC voltage to the inner electrode and an application of a second DC voltage different from the first DC voltage to the outer electrode to attract and hold the focus ring on the electrostatic chuck during a period other than a plasma processing period.

16. The substrate processing apparatus of claim 15, further comprising a supply unit for supplying a heat transfer medium to a space located between the focus ring and the electrostatic chuck while in the plasma processing period.

17. The substrate processing apparatus of claim 15, wherein the control unit is configured to control application of voltages having a same polarity to each of the inner electrode and the outer electrode during the plasma processing period, and to apply voltages of opposite polarities to the inner and outer electrodes during the period other than the plasma processing period.

18. The substrate processing apparatus of claim 16, wherein the apparatus further includes a center electrode located radially inside of the inner electrode, and wherein the control unit is configured to control application of voltages such that:

a voltage is applied to the center electrode during the plasma processing period;

a voltage is applied to at least one of the inner electrode or the outer electrode during the plasma processing period;

no voltage is applied to the center electrode during the period other than the plasma processing period, and at least two different non-zero voltages are applied to the inner and outer electrodes during the period other than the plasma processing period.

19. The substrate processing apparatus according to claim 18, wherein voltages having the same polarity are applied to each of the inner and outer electrodes during the plasma processing period, and voltages having opposite polarities are applied to the inner and outer electrode during the period other than the plasma processing period.

20. The substrate processing apparatus according to claim 18, wherein the apparatus includes a processing chamber containing the electrostatic chuck, and wherein the period other than the processing period includes at least one of a substrate loading period during which a substrate is loaded into the processing chamber or a substrate unloading period during which a substrate is unloaded from the processing chamber, and wherein during the substrate loading period or the substrate unloading period, the heat transfer medium is not supplied to the space;

and

wherein the period other than the plasma processing period further comprises a cleaning period and wherein the heat transfer medium is supplied to the space during the cleaning period.