Pulsed-mode RF bias for sidewall coverage improvement

• US 6,344,419 B1
• Filed: 12/03/1999
• Issued: 02/05/2002
• Est. Priority Date: 12/03/1999
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Hong, Liubo, Forster, John, Stimson, Bradley O., Gopalraja, Praburam
• Primary Examiner(s): Bowers, Charles
• Assistant Examiner(s): Pert, Evan
• Application Number:
  US09/454,355
• Time in Patent Office: 795 Days
• Field of Search: 438/710, 438/469, 438/466, 438/584, 438/758, 438/778, 438/788, 118/696, 118/695, 427/457, 427/523, 427/526, 427/458, 427/472, 427/569, 427/570, 427/571, 427/585, 427/598
• US Class Current: 438/758
• CPC Class Codes: C23C 14/046 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 14/345 using substrate bias
• 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 37/32431 Constructional details of the reactor
• CPC Class Codes: H01J 37/3405 Magnetron sputtering
• CPC Class Codes: H01L 21/2855 by physical means, e.g. sputtering, evaporation H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material

Abstract

The present invention provides a method and apparatus for achieving conformal step coverage of one or more materials on a substrate using sputtered ionized material. A target provides a source of material to be sputtered by a plasma and then ionized by an inductive coil, thereby producing electrons and ions. In one embodiment, one or both of the signals to the substrate and the target are modulated. Preferably, the modulated signal to the substrate includes a negative voltage portion and a zero voltage portion.

Claims

1. A method of depositing a material on a substrate in a process chamber, comprising:

(a) providing a first signal to a support member having the substrate disposed thereon;

(b) providing a second signal to a target;

(c) energizing a magnetic field generator disposed in the processing chamber;

(d) varying the first signal between a first negative voltage portion and a first zero voltage portion relative to ground during a first phase; and

(e) maintaining the first signal at a constant voltage during a second phase.

2. The method of claim 1, wherein a duty cycle of the first signal is between about 30% and about 70%.

3. The method of claim 1, wherein a duty cycle of the second signal is between about 10% and about 50%.

4. The method of claim 1, wherein (a) comprises supplying a radio frequency (RF) signal to the support member.

5. The method of claim 1, wherein (a) comprises supplying a pulsed RF signal.

6. The method of claim 1, wherein (b) comprises supplying a DC signal to the target.

7. The method of claim 1, wherein (c) comprises energizing a coil.

8. The method of claim 1, wherein (c) comprises supplying a RF signal to the magnetic field generator.

9. The method of claim 1, further comprising:

(e) supplying a gas to the chamber;

(f) sputtering a material from the target; and

(g) ionizing the sputtered material.

10. The method of claim 1, further comprising:

(e) providing a plasma to the chamber;

(f) sputtering a material from the target; and

(g) ionizing the sputtered material;

wherein (a) comprises supplying a first RF signal to the substrate, (b) comprises supplying a DC signal to the target and (c) comprises supplying a second RF signal to the magnetic field generator.

11. The method of claim 1, further comprising:

(e) varying the second signal between a second negative voltage portion and a second zero voltage portion relative to ground.

12. The method of claim 11, wherein the second signal comprises a pulsed DC signal.

13. A method of depositing a material on a substrate in a process chamber, comprising:

(a) supplying a plasma to the processing chamber;

(b) providing a first signal of a first waveform to a support member having the substrate disposed thereon;

(c) providing a second signal of a second waveform to a target;

(d) energizing a coil with a RF signal;

(e) varying the first signal between a first negative voltage portion and a first zero voltage portion relative to ground during a first phase; and

(f) maintaining the first signal at a constant voltage during a second phase.

14. The method of claim 13, wherein (b) comprises supplying a RF signal to the support member and (c) comprises supplying a DC signal to the target.

15. The method of claim 13, wherein the first signal has a duty cycle of between about 30% and about 70% and has a frequency between about 0.1 Hz and 1 MHz.

16. The method of claim 13, wherein the second signal has a duty cycle of between about 10% and about 50% and has a frequency between about 10 KHz and 1 MHz.

17. The method of claim 13, wherein the first signal and the second signal are pulsed signals.

18. The method of claim 13, wherein the first negative portion is provided to the support member during the second zero voltage portion.

19. The method of claim 18, wherein the first signal and the second signal are pulsed signals and wherein a first pulse width of the first negative portion is less than a second pulse width of the second zero voltage portion.

20. A program product, which when read and executed by one or more controllers, comprises the steps of:

(a) flowing a gas into a processing chamber;

(b) providing a second signal to a target;

(c) providing a first signal to a support member having the substrate disposed thereon;

(d) energizing a coil with an RF signal;

(e) varying the first signal between a first negative voltage portion and a first zero voltage portion relative to ground during a first phase; and

(f) maintaining the first signal at a constant voltage during a second phase.

21. The program product of claim 20, wherein (c) comprises supplying a pulsed RF signal to the support member.

22. The program product of claim 20, wherein (c) comprises supplying a pulsed signal to the support member having a negative voltage portion and a zero voltage portion.

23. The program product of claim 20, wherein (e) and (f) comprise decreasing a voltage to the target for a period of time and increasing a voltage to the support member during at least a portion of the period of time.