CREATING ION ENERGY DISTRIBUTION FUNCTIONS (IEDF)

• US 20180166249A1
• Filed: 12/07/2017
• Published: 06/14/2018
• Est. Priority Date: 12/12/2016
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: DORF, Leonid, KOH, Travis, LUERE, Olivier, JOUBERT, Olivier, KRAUS, Philip A., DHINDSA, Rajinder, ROGERS, JAMES HUGH
• Granted Patent: US 10,312,048 B2
• Time in Patent Office: Days
• CPC Class Codes: H01J 37/08 Ion sources; Ion guns
• CPC Class Codes: H01J 37/248 Components associated with high voltage supply
• CPC Class Codes: H01J 37/32577 Electrical connecting means
• CPC Class Codes: H01J 37/32706 Polarising the substrate
• CPC Class Codes: H01J 37/32715 Workpiece holder

Abstract

Systems and methods for creating arbitrarily-shaped ion energy distribution functions using shaped-pulse-bias. In an embodiment, a method includes applying a positive jump voltage to an electrode of a process chamber to neutralize a wafer surface, applying a negative jump voltage to the electrode to set a wafer voltage, and modulating the amplitude of the wafer voltage to produce a predetermined number of pulses to determine an ion energy distribution function. In another embodiment a method includes applying a positive jump voltage to an electrode of a process chamber to neutralize a wafer surface, applying a negative jump voltage to the electrode to set a wafer voltage, and applying a ramp voltage to the electrode that overcompensates for ion current on the wafer or applying a ramp voltage to the electrode that undercompensates for ion current on the wafer.

Claims

1. A method, comprising:

applying a negative jump voltage to an electrode of a process chamber to set a wafer voltage for a wafer; and

modulating an amplitude of the wafer voltage to produce a predetermined number of pulses, wherein a relative number of pulses at a specific amplitude determines a relative ion fraction at an ion energy corresponding to the specific amplitude.

2. The method of claim 1, comprising:

applying a positive jump voltage to the electrode of the process chamber to neutralize a surface of the wafer.

3. The method of claim 2, wherein the positive jump voltage is applied to the electrode of the process chamber prior to applying the negative jump voltage.

4. The method of claim 1, wherein the modulation of the amplitude of the wafer voltage controls a feature profile of a resulting ion energy distribution function.

5. The method of claim 1, wherein the amplitude of the wafer voltage is modulated to create a desired ion energy distribution function.

6. The method of claim 5, wherein the desired ion energy distribution function is created to induce a specific bias voltage waveform on the wafer.

7. The method of claim 1, comprising:

modulating the wafer voltage at different points in time to create an ion energy distribution function having more than one energy peak.

8. The method of claim 7, wherein an ion fraction for each of the energy peaks is determined by a number of pulses produced during a respective modulation of the wafer voltage at the different points in time.

9. The method of claim 1, comprising:

modulating the wafer voltage at different amplitudes to create an ion energy distribution function having more than one energy peak with different amplitudes.

10. The method of claim 9, wherein an ion fraction for each of the energy peaks is determined by a number of pulses produced during a respective modulation of the wafer voltage at the different amplitudes.

11. A method comprising:

applying a positive jump voltage to an electrode of a process chamber to neutralize a surface of a wafer;

applying a negative jump voltage to the electrode to set a wafer voltage for the wafer; and

applying a ramp voltage to the electrode that overcompensates for ion current on the wafer.

12. The method of claim 11, wherein applying a ramp voltage to the electrode that overcompensates for ion current on the wafer comprises applying a ramp voltage to the electrode that comprises a slope that is more negative than is required to maintain a constant voltage on the wafer.

13. The method of claim 11, wherein a minimum voltage and a maximum voltage of a current induced on the wafer determine a width of a resulting ion energy distribution function.

14. The method of claim 11, comprising:

adjusting a slope of the ramp voltage to create a desired ion energy distribution function.

15. The method of claim 14, wherein the desired ion energy distribution function is created to induce a specific bias voltage waveform on the wafer.

16. A method comprising:

applying a positive jump voltage to an electrode of a process chamber to neutralize a surface of a wafer;

applying a negative jump voltage to the electrode to set a wafer voltage for the wafer; and

applying a ramp voltage to the electrode that undercompensates for ion current on the wafer.

17. The method of claim 16, wherein applying a ramp voltage to the electrode that undercompensates for ion current on the wafer comprises applying a ramp voltage to the electrode that comprises a slope that is less negative than is required to maintain a constant voltage on the wafer.

18. The method of claim 16, wherein a minimum voltage and a maximum voltage of a current induced on the wafer determine a width of a resulting ion energy distribution function.

19. The method of claim 16, comprising:

adjusting a slope of the ramp voltage to create a desired ion energy distribution function.

20. The method of claim 19, wherein the desired ion energy distribution function is created to induce a specific bias voltage waveform on the wafer.