Treatment of a dielectric layer using supercritical CO2

• US 7,387,868 B2
• Filed: 03/28/2005
• Issued: 06/17/2008
• Est. Priority Date: 03/04/2002
• Status: Expired due to Fees

• Current Assignee: Tokyo Electron Limited
• Original Assignee: Tokyo Electron Limited
• Inventors: Jacobson, Gunilla, Yellowaga, Deborah
• Primary Examiner(s): Duda; Kathleen
• Application Number:
  US11/092,031
• Publication Number:
  US 20050191865A1
• Time in Patent Office: 1,177 Days
• Field of Search: 430/311, 430/313, 430/315, 430/322, 430/324, 430/325, 430/329, 430/330, 134/1, 134/1.3
• US Class Current: 430/313
• CPC Class Codes: C23C 26/00 Coating not provided for in groups C23C2/00 - C23C24/00
• CPC Class Codes: C23C 30/00 Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process C23C26/00, C23C28/00 take precedence
• CPC Class Codes: C23C 8/10 Oxidising
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes
• CPC Class Codes: H01L 21/02101 only involving supercritical fluids
• 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 21/02343 treatment by exposure to a liquid
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/31058 of organic layers
• CPC Class Codes: H01L 21/31133 by chemical means
• CPC Class Codes: H01L 21/3121 Layers comprising organo-silicon compounds
• CPC Class Codes: H01L 21/3125 layers comprising silazane compounds
• CPC Class Codes: H01L 21/316 composed of oxides or glassy oxides or oxide based glass
• CPC Class Codes: H01L 21/31629 Deposition of halogen doped silicon oxide, e.g. fluorine doped silicon oxide
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: H01L 21/76816 Aspects relating to the layout of the pattern or to the size of vias or trenches layout of the interconnections per se H01L23/528; CAD of ICs G06F30/00
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas

Abstract

A method of passivating silicon-oxide based low-k materials using a supercritical carbon dioxide passivating solution comprising a silylating agent is disclosed. The silylating agent is preferably an organosilicon compound comprising organo-groups with five carbon atoms such as hexamethyldisilazane (HMDS), chlorotrimethylsilane (TMCS), trichloromethylsilane (TCMS) and combinations thereof. In accordance with further embodiments of the invention, a post ash substrate comprising a dielectric material is simultaneously cleaned and passivated using a supercritical carbon dioxide cleaning solution.

Claims

1. A method of treating a patterned surface of a dielectric material comprising:

removing post-etch residue from a plurality of patterned features in a dielectric material with a passivating solution comprising a fluid and an amount of a silylating agent comprising organic groups; and

removing the passivating solution, wherein at least one of the plurality of patterned features is at least partially passivated with the organic groups, thereby restoring the k-value of the dielectric material to a pre-patterned value and resulting in the dielectric material being at least partially hydrophobic.

2. The method of claim 1, wherein the dielectric material comprises a low-k material.

3. The method of claim 1, wherein the dielectric material comprises an ultra-low-k material.

4. The method of claim 1, wherein the fluid comprises a supercritical fluid.

5. The method of claim 4, wherein the supercritical fluid comprises supercritical CO2.

6. The method of claim 1, wherein the organic groups comprise alkyl groups.

7. The method of claim 1, wherein the organic groups comprise less than six carbon atoms.

8. The method of claim 1, wherein the organic groups comprise an organosilicon compound.

9. The method of claim 8, wherein the organosilicon compound is selected from the group consisting of hexamethyldisilazane (HMDS), chlorotrimethylsilane (TMCS), trichloromethylsilane (TCMS), and combinations thereof.

10. The method of claim 1, wherein the passivating solution further comprises a carrier solvent.

11. The method of claim 10, wherein the carrier solvent is selected from the group consisting of N, N-dimethylacetamide (DMAc), gamma-butyrolactone (BLO), dimethyl sulfoxide (DMSO), ethylene carbonate (EC), N-methylpyrrolidone (NMP), dimethylpiperidone, propylene carbonate, alkane and combinations thereof.

12. The method of claim 1, wherein the dielectric material is maintained at temperatures in a range of approximately 40 degrees Celsius to approximately 250 degrees Celsius.

13. The method of claim 1, wherein the passivating solution is maintained at temperatures in a range of approximately 40 degrees Celsius to approximately 250 degrees Celsius.

14. The method of claim 1, wherein the removing post-etch residue from a plurality of patterned features in a dielectric material with a passivating solution further comprises circulating the passivating solution over the low-k surface.

15. The method of claim 1, wherein the passivating solution is maintained at pressures in a range of approximately 1,000 psi to approximately 9,000 psi.

16. The method of claim 1, further comprising drying at least one surface of the dielectric material prior to removing post-etch residue from a plurality of patterned features in a dielectric material with a passivating solution.

17. The method of claim 16, wherein the drying at least one surface comprises treating the at least one surface to a supercritical drying solution comprising supercritical carbon dioxide.

18. The method of claim 1, wherein the dielectric material comprises silicon-oxide.

19. The method of claim 1, wherein the dielectric material comprises a material selected from the group consisting of a carbon doped oxide (COD), a spin-on-glass (SOG), a fluoridated silicon glass (FSG), and combinations thereof.

20. A method of treating a patterned surface of a dielectric material, comprising:

removing post ash residue from at least one patterned surface of a dielectric material with a supercritical cleaning solution; and

treating the dielectric material with a passivating solution comprising a passivating agent in the supercritical cleaning solution to form a passivated dielectric surface, thereby restoring the k-value of the dielectric material to a pre-patterned value and resulting in the dielectric material being at least partially hydrophobic.

21. The method of claim 20, wherein the post ash residue comprises a polymer.

22. The method of claim 21, wherein the polymer is a photoresist polymer.

23. The method of claim 22, wherein the photoresist polymer comprises an anti-reflective dye.

24. The method of claim 20, wherein the dielectric material comprises a low-k material.

25. The method of claim 20, wherein the dielectric material comprises an ultra-low-k material.

26. The method of claim 20, wherein the post ash residue comprises an anti-reflective coating.

27. The method of claim 26, wherein the anti-reflective coating comprises an organic spin-on anti-reflective material.

28. The method of claim 20, wherein the passivating agent comprises an organosilicon compound.

29. The method of claim 28, wherein the organosilicon compound is selected from the group consisting of hexamethyldisilazane (HMDS), chlorotrimethylsilane (TMCS), trichloromethylsilane (TCMS) and combinations thereof.

30. A method of forming an at least partially hydrophobic patterned dielectric layer, the method comprising;

depositing a continuous layer of dielectric material with an initial k-value;

forming a photoresist mask over the continuous layer of dielectric material;

patterning the continuous layer of dielectric material through the photoresist mask;

removing the photoresist mask, thereby forming a post-ash residue and causing the dielectric material to have an intermediate k-value greater than the initial k-value; and

removing the post-ash residue using a supercritical solution comprising supercritical fluid and a silicon-based passivating agent, thereby causing the dielectric material to have a post-passivating k-value greater than the intermediate k-value, and thereby causing the layer of dielectric material to be at least partially hydrophobic.

31. The method of claim 30, wherein the supercritical fluid comprises supercritical carbon dioxide.

32. The method of claim 30, wherein the silicon-based passivating agent comprises an organosilicon compound.

33. The method of claim 30, wherein the supercritical fluid further comprises a carrier solvent.

34. The method of claim 33, wherein the carrier solvent is selected from the group consisting of N, N-dimethylacetamide (DMAc), gamma-butyrolactone (BLO), dimethyl sulfoxide (DMSO), ethylene carbonate (EC), N-methylpyrrolidone (NMP), dimethylpiperidone, propylene carbonate, alkane and combinations thereof.

35. The method of claim 30, wherein the initial k-value is a low k-value.

36. The method of claim 30, wherein the initial k-value is an ultra-low k-value.