Step coverage and overhang improvement by pedestal bias voltage modulation

• US 6,197,167 B1
• Filed: 10/12/1999
• Issued: 03/06/2001
• Est. Priority Date: 12/12/1997
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Tanaka, Yoichiro
• Primary Examiner(s): Nguyen, Nam
• Assistant Examiner(s): VERSTEEG, STEVEN H
• Application Number:
  US09/416,374
• Time in Patent Office: 511 Days
• Field of Search: 204/192.12, 204/192.15, 204/192.22, 204/298.06, 204/298.08
• US Class Current: 204/192.15
• CPC Class Codes: C23C 14/046 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 14/0641 Nitrides C23C14/0617 takes precedence
• CPC Class Codes: C23C 14/16 on metallic substrates or on substrates of boron or silicon
• CPC Class Codes: C23C 14/345 using substrate bias
• CPC Class Codes: C23C 14/358 Inductive energy
• 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 invention provides a method for depositing a metal film on a substrate, comprising generating a high density plasma in a chamber, sputtering metal particles from a target to the substrate, and applying a modulated radio frequency (RF) bias to the substrate during deposition. Another aspect of the invention provides an apparatus for depositing a metal film on a substrate comprising a high density plasma physical vapor deposition (HDP PVD) chamber and a controller to modulate a RF bias power applied to a substrate in the chamber.

Claims

1. A method for depositing a metal film on a substrate, comprising:

(a) generating a high density plasma in a chamber;

(b) sputtering metal from a target onto the substrate; and

(c) applying a radio frequency (RF) bias to the substrate during deposition, the RF bias comprising a first RF bias greater than about 0.0095 W/mm² for a first portion of a cycle and a second RF bias power density less than about 0.0095 W/mm² for a second portion of the cycle, wherein the bias applied in the second portion is between about 100 watts and about 500 watts.

2. The method of claim 1 wherein the first RF bias power density is between about 0.0095 W/mm² and about 0.0159 W/mm² and the second RF bias power density is between about 0.0032 W/mm² and about 0.0095 W/mm².

3. The method of claim 1 wherein the first RF bias power density is about 0.0159 W/mm² and the second RF bias power density is about 0.0064 W/mm².

4. The method of claim 1 wherein applying a RF bias to the substrate occurs for at least two cycles.

5. The method of claim 4 wherein the deposition during each RF bias is less than about 300 Å

.

6. The method of claim 1 wherein the high density plasma is generated by an inductive coil powered by an RF source at about 13.56 MHz.

7. The method of claim 1 wherein the target comprises one or more sputterable materials selected from titanium, tungsten, titanium nitride, aluminum, copper, and combinations thereof.

8. An apparatus for depositing a metal film on a substrate, comprising:

(a) a high density plasma physical vapor deposition (HDP PVD) chamber; and

(b) a controller which controls a RF bias power density applied to a substrate in the chamber between a first RF bias power density greater than about 0.0095 W/mm² for a first portion of a cycle and a second RF bias power density less than about 0.0095 W/mm² for a second portion of the cycle, wherein the bias applied in the second portion is between about 100 watts and about 500 watts.

11. The apparatus of claim 8 wherein the HDP PVD chamber comprises an ionized metal plasma (IMP) PVD chamber.

9. The apparatus of 8 wherein the first RF bias power density is between about 0.0095 W/mm² and about 0.0159 W/mm² and the second RF bias power density is between about 0.0032 W/mm² and about 0.0095 W/mm².

10. The apparatus of 8 wherein the first RF bias power density is about 0.0159 W/mm² and the second RF bias power density is about 0.0064 W/mm².

12. A method for depositing a metal film on a substrate, comprising:

(a) moving a substrate into a chamber;

(b) generating a plasma in the chamber;

(c) sputtering material from a target; and

(d) applying a radio frequency (RF) bias to the substrate during deposition, the RF bias comprising a first RF bias power density greater than about 0.0095 W/mm² for a first portion of a cycle and a second RF bias power density less than about 0.0095 W/mm² for a second portion of the cycle, wherein the bias applied in the second portion is between about 100 watts and about 500 watts.

13. The method of claim 12, further comprising flowing nitrogen into the chamber.

14. The method of claim 13, wherein the sputtered material comprises titanium.

15. The method of claim 13, wherein the nitrogen is flown into the chamber at a flow rate of about 10 to about 200 standard cubic centimeters per minute (sccm).

16. The method of claim 15, further comprising flowing an inert gas into the chamber at a flow rate of about 10 to about 100 sccm.

17. The method of claim 13, wherein the sputtered material comprises titanium and the nitrogen is flown into the chamber at about 30 sccm, and further comprising a chamber pressure of about 15 mTorr and a cycling RF substrate power density bias between about 0.0064 W/mm² and about 0.0159 W/mm².

18. The method of claim 12, wherein the RF bias is cycled between the first and second RF bias power densities for at least two cycles.

19. The method of claim 18, further comprising depositing about equal amounts of the sputtered material during each first and second portions of the at least two cycles.

20. The method of claim 18, wherein the RF bias is cycled for three cycles and a deposition thickness between about 200 Å

and about 330 Å

is deposited during each cycle.