Mechanical enhancement of dense and porous organosilicate materials by UV exposure

• US 7,098,149 B2
• Filed: 03/04/2003
• Issued: 08/29/2006
• Est. Priority Date: 03/04/2003
• Status: Active Grant

• Current Assignee: Versum Materials US Inc.
• Original Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Inventors: Lukas, Aaron Scott, Vincent, Jean Louise, Bitner, Mark Daniel, Karwacki, Eugene Joseph Jr., O'Neill, Mark Leonard, Vrtis, Raymond Nicholas
• Primary Examiner(s): Nguyen, Tuan H.
• Application Number:
  US10/379,466
• Publication Number:
  US 20040175957A1
• Time in Patent Office: 1,274 Days
• Field of Search: 438/780, 438/795, 438/778, 257/40
• US Class Current: 438/778
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/56 After-treatment
• 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 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/31695 Deposition of porous oxides or porous glassy oxides or oxide based porous glass

Abstract

Low dielectric materials and films comprising same have been identified for improved performance when used as interlevel dielectrics in integrated circuits as well as methods for making same. In one aspect of the present invention, an organosilicate glass film is exposed to an ultraviolet light source wherein the film after exposure has an at least 10% or greater improvement in its mechanical properties (i.e., material hardness and elastic modulus) compared to the as-deposited film.

Claims

1. A process for improving a material hardness and an elastic modulus of an organosilicate film, the process comprising:

depositing the organosilicate film onto at least a portion of a substrate via chemical vapor deposition of at least one chemical reagent comprising a structure-former precursor and a pore-former precursor; and

exposing the organosilicate film to an ultraviolet radiation source within a non-oxidizing atmosphere wherein the material hardness and the elastic modulus of the organosilicate film after the exposing step are higher than the material hardness and the elastic modulus of the organosilicate film before the exposing step wherein the dielectric constant of the organosilicate film after the exposing step is at least 5% less than the dielectric constant of the organosilicate film before the exposing step.

2. The process of claim 1 further comprising treating the organosilicate film with a non-ionizing radiation source.

3. The process of claim 2 wherein the treating step occurs during at least a portion of the exposing step.

4. The process of claim 2 in which the non-ionizing radiation source heats the organosilicate film to a temperature between 25 to 450°

C.

5. The process of claim 1 wherein the temperature of the organosilicate film during the depositing step ranges from 25 to 450°

C.

6. The process of claim 5 wherein the temperature of the organosilicate film during the depositing step ranges from 250 to 450°

C.

7. The process of claim 1 wherein the depositing step involves one or more processes selected from the group consisting of thermal chemical vapor deposition, plasma enhanced chemical vapor deposition, cryogenic chemical vapor deposition, chemical assisted vapor deposition, hot-filament chemical vapor deposition, photo-initiated chemical vapor deposition, or combinations thereof.

8. The process of claim 7 wherein the forming step is plasma enhanced chemical vapor deposition.

9. The process of claim 1 wherein the ultraviolet light has one or more wavelengths of about 400 nm or below.

10. The process of claim 1 wherein the ultraviolet light has one or more wavelengths of about 300 nm or below.

11. The process of claim 1 wherein the ultraviolet light has one or more wavelengths of about 200 nm or below.

12. The process of claim 1 wherein the non-oxidizing atmosphere contains at least one gas selected from the group consisting of nitrogen, hydrogen, carbon monoxide, carbon dioxide, helium, argon, neon, krypton, xenon, radon, or mixtures thereof.

13. The process of claim 1 wherein the non-oxidizing atmosphere comprises a vacuum.

14. The process of claim 13 wherein the pressure ranges from 0.05 millitorr to 500 torr.

15. The organosilicate film prepared by the process of claim 1.

16. A chemical vapor deposition method for improving a material hardness and an elastic modulus of an organosilicate film represented by the formula Si_vO_wC_xF_z, where v+w+x+v+z =100%, v is from 10 to 35 atomic %, w is from 10 to 65 atomic %, x is from 5 to 30 atomic %, y is from 10 to 50 atomic %, and z is from 0 to 15 atomic %, the method comprising:

providing a substrate within a vacuum chamber;

introducing at least one chemical reagent comprising a structure-former precursor selected from the group consisting of an organosilane and an organosiloxane and a pore-former precursor wherein at least one of pore-former precursor and the structure-former precursor is the same compound and is at least one member selected from the group consisting of 1-neohexyl-1,3,5,7-tetramethyl-cyclotetrasiloxane, di-neohexyl-diethoxysilane, 1,4-bis(diethoxysilyl)cyclohexane, or mixtures thereof into the vacuum chamber;

applying energy to the at least one chemical reagent in the vacuum chamber to induce reaction of the at least one chemical reagent to deposit an organosilicate film on at least a portion of the substrate; and

exposing the organosilicate film to an ultraviolet light source within a non-oxidizing atmosphere wherein the material hardness and the elastic modulus of the organosilicate material after the exposing step are higher than the material hardness and the elastic modulus of the organosilicate material before the exposing step.

17. The method of claim 16 further comprising heating the organosilicate film.

18. The method of claim 16 wherein the organosilane is at least one member from the group consisting of methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, phenylsilane, methylphenylsilane, cyclohexylsilane, tert-butylsilane, ethylsilane, diethylsilane, tetraethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, dimethylethoxysilane, methyldiethoxysilane, triethoxysilane, methyltriethoxysilane, trimethylphenoxysilane, phenoxysilane, ditertbutylsilane, diethoxysilane, and

mixtures thereof.

19. The method of claim 16 wherein the organosiloxane is at least one member from the group consisting of 1,3,5,7-tetramethylcyclotatrasiloxane, octamethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, hexamethyldisiloxane, 1,1,2,2-tetramethyldisiloxane, octamethyltrisiloxane, and mixtures thereof.

20. The method of claim 16 wherein the at least one chemical reagent further comprises a pore-former precursor that is different than the structure-former precursor.

21. The method of claim 20 wherein the pore-former precursor is at least one member from the group consisting of alpha-terpinene, limonene, cyclohexane, 1,2,4-trimethylcyclohexane, 1,5-dimethyl-1,5-cyclooctadiene, camphene, adamantane, 1,3-butadiene, substituted dienes and decahydronaphthelene.

22. The method of claim 16 wherein the substrate is heated during at least a portion of the exposing step.

23. The method of claim 16 wherein the applying step is conducted at a temperature of about 250°

C. or greater.

24. The organosilicate film prepared by the method of claim 16.

25. A process for improving a material hardness and an elastic modulus of an organosilicate film having a dielectric constant, the process comprising:

depositing the organosilicate film onto at least a portion of a substrate via chemical vapor deposition of at least one chemical reagent comprising a structure-former precursor provided that the at least one chemical reagent is substantially free of a pore-former precursor; and

exposing the organosilicate film to an energy source comprising an ultraviolet radiation source wherein the material hardness and the elastic modulus of the organosilicate film after the exposing step are higher than the material hardness and the elastic modulus of the organosilicate film before the exposing step and wherein the dielectric constant of the organosilicate film after the exposing step is the substantially the same as or less than the dielectric constant of the organosilicate film before the exposing step.

26. The method of claim 25 further comprising heating the organosilicate film.

27. A process for improving a material hardness and an elastic modulus of a porous organosilicate film having a dielectric constant, the process comprising:

depositing at least one chemical reagent comprising a structure-former precursor and a pore-former precursor onto at least a portion of a substrate to provide an as-deposited film; and

exposing the as-deposited film to at least one energy source comprising an ultraviolet light source to remove at least a portion of the pore-former precursor contained therein and provide the porous organosilicate film wherein the material hardness and the elastic modulus of the porous organosilicate film after the exposing step are higher than a material hardness and an elastic modulus of the as-deposited film before the exposing step and wherein the dielectric constant of the porous organosilicate film after the exposing step is at least 5% less than a dielectric constant of the as-deposited film before the exposing step.

28. The method of claim 27 further comprising heating the porous organosilicate film.

29. The method of claim 28 wherein the heating is conducted during at least a portion of exposing.

30. The method of claim 28 wherein the heating is conducted after exposing.

31. The method of claim 28 wherein the heating is conducted before exposing.