Method for curing a porous low dielectric constant dielectric film

• US 7,858,533 B2
• Filed: 03/06/2008
• Issued: 12/28/2010
• Est. Priority Date: 03/06/2008
• Status: Active Grant

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Toma, Dorel I., Lee, Eric M., Liu, Junjun
• Primary Examiner(s): Mulpuri; Savitri
• Assistant Examiner(s): CHOI, CALVIN Y
• Application Number:
  US12/043,772
• Publication Number:
  US 20090227119A1
• Time in Patent Office: 1,027 Days
• Field of Search: 438778-788
• US Class Current: 438/778
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02216 the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/02345 treatment by exposure to radiation, e.g. visible light
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/31695 Deposition of porous oxides or porous glassy oxides or oxide based porous glass

Abstract

A method of curing a low dielectric constant (low-k) dielectric film on a substrate is described, wherein the dielectric constant of the low-k dielectric film is less than a value of approximately 4. The method comprises exposing the low-k dielectric film to infrared (IR) radiation and ultraviolet (UV) radiation.

Claims

1. A method of curing a low dielectric constant (low-k) dielectric film on a substrate, comprising:

forming a low-k dielectric film on a substrate;

exposing said low-k dielectric film to a first infrared (IR) radiation;

exposing said low-k dielectric film to ultraviolet (UV) radiation following said exposure to said first IR radiation; and

exposing said low-k dielectric film to a second infrared (IR) radiation following said exposure to said UV radiation,

wherein a dielectric constant of said low-k dielectric film is less than a value of approximately 4.

2. The method of claim 1, further comprising:

during said first IR exposure, heating said low-k dielectric film by elevating a temperature of said substrate to a first IR thermal treatment temperature ranging from approximately 200 degrees C. to approximately 600 degrees C.

3. The method of claim 2, wherein said first IR thermal treatment temperature ranges from approximately 350 degrees C. to approximately 450 degrees C.

4. The method of claim 1, further comprising:

during said UV exposure, heating said low-k dielectric film by elevating a temperature of said substrate to a UV thermal temperature ranging from approximately 200 degrees C. to approximately 600 degrees C.

5. The method of claim 4, wherein said UV thermal temperature ranges from approximately 300 degrees C. to approximately 500 degrees C.

6. The method of claim 1, further comprising:

during said second IR exposure, heating said low-k dielectric film by elevating a temperature of said substrate to a second IR thermal treatment temperature ranging from approximately 200 degrees C. to approximately 600 degrees C.

7. The method of claim 6, wherein said second IR thermal treatment temperature ranges from approximately 350 degrees C. to approximately 450 degrees C.

8. The method of claim 1, wherein said first IR exposure is performed in a process system different from said UV exposure.

9. The method of claim 1, wherein said first IR exposure is performed in the same process system as said UV exposure.

10. The method of claim 1, wherein said exposing said low-k dielectric film to UV radiation comprises exposing said low-k dielectric film to polychromatic UV radiation, monochromatic UV radiation, pulsed UV radiation, or continuous wave UV radiation, or a combination of two or more thereof

11. The method of claim 1, wherein said exposing said low-k dielectric film to UV radiation comprises exposing said low-k dielectric film to UV radiation from one or more UV lamps, one or more UV LEDs, or one or more UV lasers, or a combination of two or more thereof

12. The method of claim 1, wherein said exposing said low-k dielectric film to UV radiation comprises exposing said low-k dielectric film to UV radiation with a wavelength ranging from approximately 200 nanometers to approximately 400 nanometers.

13. The method of claim 1, wherein said exposing said low-k dielectric film to UV radiation comprises exposing said low-k dielectric film to UV radiation with a wavelength ranging from approximately 200 nanometers to approximately 240 nanometers.

14. The method of claim 1, wherein said exposing said low-k dielectric film to said first IR radiation comprises exposing said low-k dielectric film to polychromatic IR radiation, monochromatic IR radiation, pulsed IR radiation, or continuous wave IR radiation, or a combination of two or more thereof

15. The method of claim 1, wherein said exposing said low-k dielectric film to said first IR radiation comprises exposing said low-k dielectric film to IR radiation from one or more IR lamps, one or more IR LEDs, or one or more IR lasers, or a combination of two or more thereof

16. The method of claim 1, wherein said exposing said low-k dielectric film to said first IR radiation or said second IR radiation comprises exposing said low-k dielectric film to IR radiation with a wavelength ranging from approximately 8 micron to approximately 12 microns.

17. The method of claim 1, wherein said exposing said low-k dielectric film to UV radiation further comprises:

exposing said low-k dielectric film to third IR radiation during at least a portion of said UV exposure.

18. The method of claim 17, wherein said exposing said low-k dielectric film to said third IR radiation comprises exposing said low-k dielectric film to IR radiation with a wavelength_—

ranging from approximately 8 microns to approximately 12 microns.

19. The method of claim 1, further comprising:

treating said dielectric film following said second IR exposure by performing one or more of depositing another film on said dielectric film, cleaning said dielectric film, or exposing said dielectric film to plasma.

20. The method of claim 1, wherein said low-k dielectric film comprises a porous low-k dielectric film comprising a structure-forming material and a pore-generating material.

21. The method of claim 20, wherein said structure-forming material comprises diethoxymethylsilane (DEMS).

22. The method of claim 20, wherein said pore-generating material comprises a terpene;

a norbornene;

5-dimethyl-1,4-cyclooctadiene;

decahydronaphthalene;

ethylbenzene;

or limonene;

or a combination of two or more thereof

23. The method of claim 1, further comprising:

exposing said low-k dielectric film to second UV radiation during said first IR exposure, wherein said second UV radiation is different than said UV radiation following said first IR exposure.

24. The method of claim 23, wherein said second UV radiation comprises exposing said low-k dielectric film to UV radiation with a wavelength ranging from approximately 300 nanometers to approximately 450 nanometers.

25. A method of curing a low dielectric constant (low-k) dielectric film on a substrate, comprising:

forming a low-k dielectric film on a substrate, said low-k dielectric film comprising a structure-forming material and a pore-generating material;

substantially removing said pore-generating material from said low-k dielectric film to form a porous low-k dielectric film;

generating cross-linking initiators in said porous low-k dielectric film following said removing; and

cross-linking said porous low-k dielectric film following said generation of said cross-linking initiators.

26. The method of claim 25, further comprising:

breaking bonds in said low-k dielectric film in order to assist said removing.