METHOD TO INCREASE SILICON NITRIDE TENSILE STRESS USING NITROGEN PLASMA IN-SITU TREATMENT AND EX-SITU UV CURE

• US 20080020591A1
• Filed: 06/13/2007
• Published: 01/24/2008
• Est. Priority Date: 05/26/2005
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Witty, Derek, Xia, Li-Qun, Nguyen, Victor, Balseanu, Mihaela, M'Saad, Hichem, Shek, Mei-Yee, Roflox, Isabelita
• Granted Patent: US 8,138,104 B2
• Time in Patent Office: Days
• US Class Current: 438/761
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: H01L 21/823807 with a particular manufacturing method of the channel structures, e.g. channel implants, halo or pocket implants, or channel materials
• CPC Class Codes: H01L 29/6656 using multiple spacer layers, e.g. multiple sidewall spacers
• CPC Class Codes: H01L 29/66583 with initial gate mask or masking layer complementary to the prospective gate location, e.g. with dummy source and drain contacts
• CPC Class Codes: H01L 29/6659 with both lightly doped source and drain extensions and source and drain self-aligned to the sides of the gate, e.g. lightly doped drain [LDD] MOSFET, double diffused drain [DDD] MOSFET
• CPC Class Codes: H01L 29/7843 the means being an applied insulating layer

Abstract

Stress of a silicon nitride layer may be enhanced by deposition at higher temperatures. Employing an apparatus that allows heating of a substrate to substantially greater than 400° C. (for example a heater made from ceramic rather than aluminum), the silicon nitride film as-deposited may exhibit enhanced stress allowing for improved performance of the underlying MOS transistor device. In accordance with alternative embodiments, a deposited silicon nitride film is exposed to curing with ultraviolet (UV) radiation at an elevated temperature, thereby helping remove hydrogen from the film and increasing film stress. In accordance with still other embodiments, a silicon nitride film is formed utilizing an integrated process employing a number of deposition/curing cycles to preserve integrity of the film at the sharp corner of the underlying raised feature. Adhesion between successive layers may be promoted by inclusion of a post-UV cure plasma treatment in each cycle.

Claims

1. A method of forming silicon nitride, the method comprising:

(i) disposing a substrate including a surface on a ceramic support in a processing chamber; and

(ii) depositing a silicon nitride layer on the surface by exposing the surface to a silicon-containing precursor gas at a temperature of greater than 400°

C.

2. The method of claim 1 wherein the substrate is disposed on a ceramic support comprising aluminum nitride, graphite, silicon carbide, alumina, or Ytria.

3. The method of claim 1 wherein the surface is exposed to the silicon-containing precursor gas at a temperature of 480°

C. or greater.

4. The method of claim 1 further comprising exposing the silicon nitride to ultraviolet radiation while the temperature of the substrate is maintained at greater than 400°

C.

5. The method of claim 1 wherein deposition at a temperature of greater than 400°

C. creates a higher stress in the silicon nitride as compared with deposition at a lower temperature.

6. The method of claim 1 wherein the silicon nitride film is deposited over a raised gate of a transistor structure present in the substrate.

7. The method of claim 1 further comprising:

depositing a second silicon nitride layer over the silicon nitride layer; and

exposing the second silicon nitride layer to ultraviolet radiation.

8. The method of claim 7 further comprising:

exposing the silicon nitride layer to a plasma prior to deposition of the second silicon nitride layer.

9. The method of claim 7 wherein the silicon nitride layer and the second silicon nitride layer have thicknesses of 1000 Å

or less.

10. The method of claim 1 wherein the silicon nitride layer comprises silicon oxynitride or doped silicon nitride.

11. A method of forming silicon nitride, the method comprising:

(i) disposing a substrate including a surface in a processing chamber;

(ii) forming a silicon nitride layer on the surface;

(iii) forming another silicon nitride layer over the existing silicon nitride layer;

(iv) exposing the silicon nitride to ultraviolet radiation; and

repeating steps (iii)-(iv) to increase a thickness of the silicon nitride.

12. The method of claim 11 further comprising exposing the existing silicon nitride to a plasma prior to formation of additional silicon nitride thereon.

13. The method of claim 11 wherein the silicon nitride film is deposited over a raised gate of a transistor structure present in the substrate.

14. The method of claim 11 wherein the silicon nitride layers have thicknesses of 1000 Å

or less.

15. The method of claim 11 further comprising heating the silicon nitride layers during and/or following exposure to the ultraviolet radiation.

16. The method of claim 11 wherein the deposition and UV exposure steps are performed in different chambers of a cluster tool.

17. A method of forming a dielectric film on a substrate, comprising:

placing a substrate with at least one formed feature across a surface of the substrate into a chamber;

depositing a dielectric layer on the surface of the substrate;

treating the dielectric layer with plasma; and

treating the dielectric layer with a UV source.

18. The method of claim 17, further comprising repeating depositing a dielectric layer and treating the dielectric layer with a plasma.

19. The method of claim 17, wherein the dielectric layer comprises silicon oxide, silicon oxynitride, silicon nitride, or doped silicon nitride.

20. The method of claim 17, wherein the depositing a dielectric layer and treating the dielectric layer with plasma are performed in the same chamber.

21. The method of claim 17, wherein the treating of the dielectric layer with a UV source is performed in a second chamber comprising a UV source.

22. The method of claim 17, wherein the plasma includes argon, nitrogen, Xenon, or Helium.

23. The method of claim 17 further comprising treating the dielectric layer with plasma.

24. The method of claim 23, further comprising repeating depositing a dielectric layer, treating the dielectric layer with a plasma, treating the dielectric layer with a UV source, and treating the dielectric layer with a plasma.

25. The method of claim 23, wherein the depositing a dielectric layer, treating the dielectric layer with plasma, treating the dielectric layer with a UV source, and treating the dielectric layer with a plasma are performed in an integrated deposition/UV system.

26. The method of claim 23, wherein the plasma includes argon, nitrogen, helium, or Xenon.