Ultraviolet assisted pore sealing of porous low k dielectric films

• US 20060105566A1
• Filed: 11/12/2004
• Published: 05/18/2006
• Est. Priority Date: 11/12/2004
• Status: Active Grant

• Current Assignee: Axcelis Technologies Incorporated
• Original Assignee: Axcelis Technologies Incorporated
• Inventors: Escorcia, Orlando, Berry, Ivan, Waldfried, Carlo
• Granted Patent: US 7,678,682 B2
• Time in Patent Office: Days
• US Class Current: 438/637
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/02107 Forming insulating materials on a substrate
• CPC Class Codes: H01L 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02337 treatment by exposure to a gas or vapour
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/31051 Planarisation of the insulating layers H01L21/31058 takes precedence
• CPC Class Codes: H01L 21/31058 of organic layers
• CPC Class Codes: H01L 21/31695 Deposition of porous oxides or porous glassy oxides or oxide based porous glass
• CPC Class Codes: H01L 21/76825 by exposing the layer to particle radiation, e.g. ion implantation, irradiation with UV light or electrons etc. plasma treatment H01L21/76826
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas

Abstract

Processes for sealing porous low k dielectric film generally comprises exposing the porous surface of the porous low k dielectric film to ultraviolet (UV) radiation at intensities, times, wavelengths and in an atmosphere effective to seal the porous dielectric surface by means of carbonization, oxidation, and/or film densification. The surface of the surface of the porous low k material is sealed to a depth less than or equal to about 20 nanometers, wherein the surface is substantially free of pores after the UV exposure.

Claims

1. A process for sealing a porous low k dielectric material disposed on a substrate, comprising:

exposing a surface of the porous low k dielectric material to an ultraviolet radiation pattern for a period of time, intensity, and wavelength effective to seal the surface of the porous low k material to a depth less than or equal to about 20 nanometers, wherein the surface is substantially free of open pores.

2. The process of claim 1, wherein the ultraviolet radiation pattern comprises broadband wavelengths less than 400 nanometers.

3. The process of claim 1, wherein the ultraviolet radiation pattern comprises broadband wavelengths between about 100 and 400 nanometers.

4. The process of claim 1, wherein exposing the surface of the porous low k dielectric material to the ultraviolet radiation pattern for a period of time, intensity and wavelength is in a reactive purge environment

5. The process of claim 1, wherein exposing the surface of the porous low k dielectric material to the ultraviolet radiation pattern is in an atmosphere of N₂, H₂, Ar, He, Ne, H₂O vapor, NH₃, CO, CO₂, O₂, O₃, C_xH_y, C_xF_y, C_xH_zF_y, and mixtures thereof, wherein x is an integer between 1 and 6, y is an integer between 4 and 14, and z is an integer between 1 and 14.

6. The process of claim 1, wherein exposing the porous low k dielectric material the ultraviolet radiation pattern is for a period of time, intensity, and wavelength effective to seal a surface of the porous low k material to a depth less than or equal to about 10 nanometers.

7. The process of claim 1, wherein exposing the porous low k dielectric material the ultraviolet radiation pattern is for a period of time, intensity and wavelength effective to seal a surface of the porous low k material to a depth about equal to an average pore diameter.

8. A process for forming an electrical interconnect structure, comprising:

patterning a porous low k dielectric material disposed on a substrate;

exposing the porous low k dielectric film to ultraviolet radiation for a period of time, intensity, and wavelength pattern effective to seal the surface of the porous low k material to a depth less than or equal to about 20 nanometers, wherein the surface is substantially free of open pores; and

depositing a barrier layer and/or a conductive layer onto the patterned porous low k dielectric material, wherein the barrier layer is substantially free of pinholes.

9. The process according to claim 8, further comprising depositing the barrier layer onto the porous low k dielectric material prior to depositing the conductive layer.

10. The process according to claim 8, wherein the ultraviolet radiation comprises broadband wavelengths of less than 400 nanometers.

11. The process according to claim 8, wherein the ultraviolet exposure is performed in an atmosphere of N₂, H₂, Ar, He, Ne, H₂O vapor, NH₃, CO, CO₂, O₂, O₃, C_xH_y, C_xF_y, C_xH_zF_y, and mixtures thereof, wherein x is an integer between 1 and 6, y is an integer between 4 and 14, and z is an integer between 1 and 14.

12. A process for sealing a porous low k dielectric material disposed on a substrate, comprising:

oxidizing a surface of the porous low k dielectric material by exposing the surface to an ultraviolet radiation pattern for a period of time, intensity, and wavelength effective in an atmosphere comprising oxygen to seal the surface of the porous low k material to a depth less than or equal to about 20 nanometers.

13. The process according to claim 12, wherein the ultraviolet radiation pattern comprises broadband wavelengths of less than 400 nanometers.

14. The process according to claim 12, further comprising annealing the porous low k dielectric material after exposing the porous low k dielectric material to the ultraviolet radiation.

15. A process for sealing a porous low k dielectric material disposed on a substrate, comprising:

carbonizing a surface of the porous low k dielectric material by exposing the surface to an ultraviolet radiation pattern for a period of time, intensity and wavelength effective to seal the surface of the porous low k material to a depth less than or equal to about 20 nanometers.

16. The process according to claim 15, wherein the ultraviolet radiation comprises broadband wavelengths of less than 400 nanometers.

17. The process according to claim 15, further comprising annealing the porous low k dielectric material after exposing the porous low k dielectric material to the ultraviolet radiation.

18. A process for sealing a porous low k dielectric material disposed on a substrate, comprising:

densifying a surface of the porous low k dielectric material by exposing the surface to n ultraviolet radiation pattern for a period of time, intensity, and wavelength effective to seal the surface of the porous low k material to a depth less than or equal to about 20 nanometers.

19. The process according to claim 19, wherein the ultraviolet radiation comprises broadband wavelengths of less than 400 nanometers.

20. The process according to claim 19, further comprising annealing the porous low k dielectric material after exposing the porous low k dielectric material to the ultraviolet radiation.

21. A process for sealing a porous low k dielectric material disposed on a substrate, comprising:

exposing a surface of the porous low k dielectric material to an ultraviolet radiation pattern or a period of time, intensity, and wavelength effective to generate surface bonds and form reactive sites on the surface; and

reacting the reactive sites with a material to seal the surface, wherein the surface after reacting the surface with the material is substantially free of open pores.

22. The process of claim 21, wherein exposing the surface of the porous low k dielectric material to the ultraviolet radiation pattern for a period of time, intensity, and wavelength further comprises introducing a reactive gas during the exposure.

23. The process of claim 22, wherein the reactive gas is composed of N₂, H₂, H₂O vapor, NH₃, CO, CO₂, O₂, O₃, C_xH_y, C_xF_y, C_xH_zF_y, and mixtures thereof, wherein x is an integer between 1 and 6, y is an integer between 4 and 14, and z is an integer between 1 and 14.

24. A process for sealing a porous low k dielectric material disposed on a substrate, comprising:

exposing a surface of the porous low k dielectric material to a sealant material and an ultraviolet radiation pattern or a period of time, intensity, and wavelength effective to generate a surface bonds and form reactive sites on the surface; and

reacting the sealing material to seal the surface, wherein the surface is substantially free of open pores.

25. The process of claim 24, wherein exposing the surface of the porous low k dielectric material to the ultraviolet radiation pattern for a period of time, intensity, and wavelength further comprises introducing a reactive gas during the exposure.

26. The process of claim 25, wherein the reactive gas is composed of N₂, H₂, H₂O vapor, NH₃, CO, CO₂, O₂, O₃, C_xH_y, C_xF_y, C_xH_zF_y , and mixtures thereof, wherein x is an integer between 1 and 6, y is an integer between 4 and 14, and z is an integer between 1 and 14.

27. A process for sealing a porous low k dielectric material disposed on a substrate, comprising:

exposing a surface of the porous low k dielectric material to a sealant precursor and ultraviolet radiation for a period of time, intensity, and wavelength effective to generate a surface bonds and form reactive sites on the surface; and

reacting the sealant precursor with the reactive sites and surface bonds to seal the surface, wherein the surface is substantially free of open pores.

28. The process of claim 27, wherein a reactive gas is used during UV exposure to assist in the reaction with sealant material or sealant precursor.

29. The process of claim 28, wherein the reactive gas is composed of N₂, H₂, H₂O vapor, NH₃, CO, CO₂, O₂, O₃, C_xH_y, C_xF_y, C_xH_zF_y, and mixtures thereof, wherein x is an integer between 1 and 6, y is an integer between 4 and 14, and z is an integer between 1 and 14.