Plasma curing process for porous low-k materials

• US 6,913,796 B2
• Filed: 09/14/2001
• Issued: 07/05/2005
• Est. Priority Date: 03/20/2000
• Status: Expired due to Fees

• Current Assignee: Dow Corning Corporation (Dow, Inc.)
• Original Assignee: Axcelis Technologies Incorporated, Dow Corning Corporation (Dow, Inc.)
• Inventors: Bremmer, Jeff, Bargeron, Cory, Dembowski, Phil, Berry, Ivan L. III, Escorcia, Orlando, Waldfried, Carlo, Han, Qingyuan, Sbrockey, Nick, Albano, Ralph
• Primary Examiner(s): PADGETT, MARIANNE L
• Application Number:
  US09/952,649
• Publication Number:
  US 20020106500A1
• Time in Patent Office: 1,390 Days
• Field of Search: 427/488, 427/489, 427/536, 427/535, 427/539, 427/397.7, 427/397.8, 427/493, 427/508, 427/510, 427/509, 427/515, 427/553, 427/554, 427/558, 438/788, 438/787, 438/789, 438/790
• US Class Current: 427/536
• CPC Class Codes: C01B 33/126 Preparation of silica of undetermined type
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: H01L 21/02118 carbon based polymeric organic or inorganic material, e.g. polyimides, poly cyclobutene or PVC polymers per se C08G, photoresist per se G03F
• 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 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02282 liquid deposition, e.g. spin-coating, sol-gel techniques, spray coating
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/3122 layers comprising polysiloxane compounds
• CPC Class Codes: H01L 21/31695 Deposition of porous oxides or porous glassy oxides or oxide based porous glass
• CPC Class Codes: Y10T 428/249953 Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

Low dielectric constant porous materials with improved elastic modulus and hardness. The process of making such porous materials involves providing a porous dielectric material and plasma curing the porous dielectric material to produce a plasma cured porous dielectric material. Plasma curing of the porous dielectric material yields a material with improved modulus and hardness. The improvement in elastic modulus is typically greater than or about 50%, more typically greater than or about 100%, and more typically greater than or about 200%. The improvement in hardness is typically greater than or about 50%. The plasma cured porous dielectric material can optionally be post-plasma treated. The post-plasma treatment of the plasma cured porous dielectric material reduces the dielectric constant of the material while maintaining an improved elastic modulus and hardness as compared to the plasma cured porous dielectric material. The post-plasma treated, plasma cured porous dielectric material has a dielectric constant between about 1.1 and about 3.5 and an improved elastic modulus and hardness.

Claims

1. A process for making a plasma cured material from an uncured porous dielectric material comprising:

providing the uncured porous dielectric material produced by a spin-on process, the material having a first dielectric constant, having a first elastic modulus, and having a first hardness, wherein

the porous dielectric material is selected from a hydrogen silsesquioxane dielectric material or a mixed hydrogen silsesquioxane/methylsilsesquioxane dielectric material, and

the porous dielectric material is not a porous methylsilsesquioxane-based dielectric material;

exposing the uncured porous dielectric material to a plasma; and

plasma curing the uncured porous dielectric material to produce a plasma cured porous dielectric material having a second dielectric constant which is substantially equal to the first dielectric constant, having a second elastic modulus which is greater than the first elastic modulus, and having a second hardness which is greater than the first hardness.

2. The process of claim 1 wherein the porous dielectric material is selected from a porogen-generated porous dielectric material, a solvent-based porous dielectric material, a molecular engineered porous dielectric material, or a combination thereof.

3. The process of claim 1 wherein the porous dielectric material is plasma cured at a temperature between about 80°

C. and about 350°

C.

4. The process of claim 1 wherein the porous dielectric material is plasma cured at a temperature between about 150°

C. and about 300°

C.

5. The process of claim 1 wherein the porous dielectric material is plasma cured at a process pressure between about 1 Torr and about 10 Torr.

6. The process of claim 1 wherein the porous dielectric material is plasma cured for a time between about 15 and about 120 seconds.

7. The process of claim 1 wherein the plasma gas is selected from H₂ plasma gas, N₂ plasma gas, fluorine-containing plasma gas, O₂ plasma gas, or combinations thereof.

8. The process of claim 1 wherein the increase in elastic modulus between the first elastic modulus of the porous dielectric material and the second elastic modulus of the plasma cured porous dielectric material is greater than or about 50%.

9. The process of claim 1 wherein the increase in elastic modulus between the first elastic modulus of the porous dielectric material and the second elastic modulus of the plasma cured porous dielectric material is greater than or about 100%.

10. The process of claim 1 wherein the second elastic modulus of the plasma cured porous dielectric material is greater than or about 2.0 GPa.

11. The process of claim 1 wherein the second elastic modulus of the plasma cured porous dielectric material is between about 2.5 GPa and about 10 GPa.

12. The process of claim 1 wherein the increase in hardness between the first hardness of the porous dielectric material and the second hardness of the plasma cured porous dielectric material is greater than or about 50%.

13. The process of claim 1 wherein the second hardness of the plasma cured porous dielectric material is greater than or about 0.25 GPa.

14. The process of claim 1 wherein the second hardness of the plasma cured porous dielectric material is between about 0.25 GPa and about 0.8 GPa.

15. The process of claim 1 further comprising post-plasma treating the plasma cured porous dielectric material to provide a post-plasma treated, plasma cured porous dielectric material having a third dielectric constant which is less than or about equal to the second dielectric constant, having a third elastic modulus which is greater than or about equal to the second elastic modulus, and having a third hardness which is greater than or about equal to the second hardness.

16. The process of claim 15 wherein the third dielectric constant of the post-plasma treated, plasma cured porous dielectric material is between about 1.1 and about 3.5.

17. The process of claim 15 wherein the third dielectric constant of the post-plasma treated, plasma cured porous dielectric material is between about 1.8 and about 2.4.

18. The process of claim 15 wherein the post-plasma treating is annealing.

19. The process of claim 18 wherein the plasma cured porous dielectric material is annealed at a temperature less than or about 450°

C.

20. The process of claim 18 wherein the plasma cured porous dielectric material is annealed at a temperature between about 150°

C. and about 450°

C.

21. The process of claim 18 wherein the plasma cured porous dielectric material is annealed for no more than or about 60 minutes.

22. The process of claim 15 wherein the post-plasma treating is UV treating by exposing the plasma cured porous dielectric material to UV radiation at elevated temperatures.

23. The process of claim 22 wherein the plasma cured porous dielectric material is UV treated at a UV power between greater than 0 and about 1000 mW/cm2.

24. The process of claim 22 wherein the plasma cured porous dielectric material is UV treated at a temperature between about 100°

C. and about 300°

C.

25. The process of claim 22 wherein the plasma cured porous dielectric material is UV treated for no more than or about 300 seconds.

26. The process of claim 22 wherein the plasma cured porous dielectric material is UV treated at a process pressure that is less than or about equal to atmospheric pressure.

27. The process of claim 22 wherein the plasma cured porous dielectric material is UV treated with a gas purge, wherein the gas is selected from H₂, N₂, O₂, Ar, He, air, or combinations thereof.

28. The process of claim 15 wherein the post-plasma treating is plasma treating by exposing the plasma cured porous dielectric material to a second plasma condition at elevated temperatures.

29. The process of claim 28 wherein the plasma cured porous dielectric material is plasma treated at a plasma power between about 500 W and about 3000 W.

30. The process of claim 28 wherein the plasma cured porous dielectric material is plasma treated at a temperature between about 100°

C. and about 450°

C.

31. The process of claim 28 wherein the plasma cured porous dielectric material is plasma treated for no more than or about 90 seconds.

32. The process of claim 28 wherein the plasma cured porous dielectric material is plasma treated at a process pressure between about 1 Torr and about 10 Torr.

33. The process of claim 28 wherein the plasma cured porous dielectric material is plasma treated with a plasma gas, wherein the plasma gas is selected from O₂, N₂, H₂, Ar, He, fluorine-containing gas, or a combination thereof.

34. The process of claim 22 wherein the plasma cured porous dielectric material is UV treated at a process pressure that is greater than or about equal to atmospheric pressure.