Wafer Chucking System for Advanced Plasma Ion Energy Processing Systems

• US 20120052599A1
• Filed: 07/28/2011
• Published: 03/01/2012
• Est. Priority Date: 08/29/2010
• Status: Active Grant

• Current Assignee: AES Global Holdings Pte Ltd. (Advanced Energy Industries, Inc. (China))
• Original Assignee: Advanced Energy Industries Incorporated
• Inventors: Brouk, Victor, Hoffman, Daniel J.
• Granted Patent: US 9,435,029 B2
• Time in Patent Office: Days
• US Class Current: 438/5
• CPC Class Codes: C23C 14/345 using substrate bias
• CPC Class Codes: C23C 16/50 using electric discharges generation and control of plasma in discharge tubes for surface treatment H01J37/32, H01J37/34
• CPC Class Codes: H01J 37/32009 Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources plasma generation in general H05H1/24
• CPC Class Codes: H01J 37/32082 Radio frequency generated discharge H01J37/32357, H01J37/32366, H01J37/32394 and H01J37/32403 take precedence
• CPC Class Codes: H01J 37/32174 Circuits specially adapted for controlling the RF discharge
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01J 37/3299 Feedback systems

Abstract

Systems, methods and apparatus for regulating ion energies in a plasma chamber and chucking a substrate to a substrate support are disclosed. An exemplary method includes placing a substrate in a plasma chamber, forming a plasma in the plasma chamber, controllably switching power to the substrate so as to apply a periodic voltage function to the substrate, and modulating, over multiple cycles of the periodic voltage function, the periodic voltage function responsive to a desired distribution of energies of ions at the surface of the substrate so as to effectuate the desired distribution of ion energies on a time-averaged basis.

Claims

1. A system for plasma-based processing, comprising:

a plasma processing chamber configured to contain a plasma;

an electrostatic chuck positioned within the plasma processing chamber and coupled to a substrate,

an ion-energy control portion, the ion-energy control portion provides at least one ion-energy control signal responsive to at least one ion-energy distribution setting that is indicative of a desired distribution of ion energy distribution at the surface of the substrate;

a switch-mode power supply coupled to the electrostatic chuck and the ion-energy control portion, the switch-mode power supply including one or more switching components configured to provide a periodic voltage function, responsive to the ion energy control signal, to the electrostatic chuck, wherein the periodic voltage function has an AC waveform and a DC offset, the AC waveform being proportional to the desired ion energy distribution of the plasma at the surface of the substrate, the DC offset being proportional to a chucking potential maintaining the coupling between the substrate and the electrostatic chuck; and

an ion current compensation component coupled to the electrostatic chuck, the ion current compensation component effecting controllable width of the ion energy distribution.

2. The system of claim 1, wherein the switch mode power supply is floating and the DC offset is generated external to the switch mode power supply.

3. The system of claim 1, wherein the switch mode power supply includes a DC offset that generates the DC offset.

4. The system of claim 3, wherein the switch mode power supply includes an AC power source that generates the AC waveform, and wherein the AC power source is coupled in series between the DC power source and the electrostatic chuck.

5. The system of claim 4, wherein the DC power source is coupled in series between ground and the switch mode power supply.

6. The apparatus of claim 4, wherein the AC waveform is generated by the AC power source, and wherein the DC offset is generated by the DC power source, and wherein the AC power source and the DC power source are coupled to the electrostatic chuck in parallel.

7. The system of claim 1, wherein the AC waveform is provided to the electrostatic chuck via a first conductor, and the DC offset is provided to the electrostatic chuck via a second conductor.

8. The system of claim 1, wherein the chucking potential exists between a top surface of the electrostatic chuck and a reference layer within the substrate.

9. The system of claim 1, wherein the switch-mode power supply is configured to apply a periodic voltage function to the substrate support responsive to the one or more drive signals;

wherein the ion-energy control portion is configured to modulate, over multiple cycles of the periodic voltage function, at least one parameter of the periodic voltage function responsive to the at least one ion-energy distribution setting so as to generate the desired ion energy distribution at the surface of the substrate on a time-averaged basis.

10. The system of claim 9, wherein the at least one parameter includes a voltage amplitude.

11. An apparatus for plasma-based processing, comprising:

a controller configured to provide one or more drive-control signals;

a switch mode power supply providing a periodic voltage function, responsive to the one or more drive-control signals, to an electrostatic chuck of a plasma processing chamber, wherein the periodic voltage function has an AC waveform proportional to an ion energy density of a plasma at a surface of a substrate coupled to the electrostatic chuck, wherein the AC waveform is generated by an AC power source of the switch mode power supply, and wherein the switch mode power supply is configured to be connected in series with a DC power source for providing a DC offset to the AC waveform.

12. The apparatus of claim 11, wherein the switch mode power supply is floating.

13. The apparatus of claim 11, wherein the switch mode power supply comprises at least a parallel arrangement of a controllable voltage source and a controllable current source, and wherein the AC waveform is an output of the parallel arrangement.

14. A method for plasma-based processing, comprising:

placing a substrate in a plasma chamber;

forming a plasma in the plasma chamber;

controllably switching power to the substrate so as to apply a periodic voltage function to the substrate, wherein the periodic voltage function has a DC offset generated by a DC power source in series with a switch mode power supply, and wherein the DC offset generates a chucking potential between the substrate and an electrostatic chuck; and

modulating, over multiple cycles of the periodic voltage function, the periodic voltage function responsive to a desired ion energy distribution at the surface of the substrate so as to effectuate the desired ion energy distribution on a time-averaged basis.

15. The method of claim 14 wherein modulating the periodic voltage function includes modulating an amplitude of the periodic voltage function.

16. The method of claim 14 including:

obtaining values of parameters that define the desired distribution of energies of ions at the surface of the substrate;

converting the obtained parameter values to modulation data; and

modulating the periodic voltage function using the modulation data.

17. The method of claim 16, wherein the values of parameters are obtained from an operator managing the plasma-based processing.

18. The method of claim 14 including:

selecting the desired distribution of ion energies from a memory including data that defines a plurality of ion energy distribution functions so as to select a particular ion energy distribution function; and

modulating the periodic voltage function so as to effectuate the particular ion energy distribution function on a time-averaged basis.

19. The method of claim 14, including applying the controllably switched power to the substrate support to ignite and sustain the plasma in the plasma processing chamber.

20. The method of claim 14, including:

controlling an ion compensation current so as to enable control of a spread of uniform ion energies at the surface of the substrate on a time-averaged basis.

21. A method for plasma-based processing, comprising:

placing a substrate in a plasma chamber;

forming a plasma in the plasma chamber;

receiving at least one ion-energy distribution setting that is indicative of one or more ion energies at a surface of the substrate; and

controllably switching power, having an AC waveform and a DC offset, to the substrate so as to effectuate;

a desired distribution of ion energies on a time-averaged basis; and

a desired chucking potential on a time-averaged basis.

22. The method of claim 21, wherein controllably switching power includes:

combining in series an AC waveform modulated over multiple cycles of a periodic voltage function with a DC offset, the periodic voltage function responsive to the at least one ion-energy distribution setting that is indicative of one or more ion energies at the surface of the substrate so as to effectuate the desired distribution of ion energies on a time averaged basis.

23. The method of claim 22, wherein receiving at least one ion-energy distribution setting includes receiving data defining an ion energy distribution function.