Method of fabricating low-dielectric constant interlevel dielectric films for BEOL interconnects with enhanced adhesion and low-defect density

• US 6,455,443 B1
• Filed: 02/21/2001
• Issued: 09/24/2002
• Est. Priority Date: 02/21/2001
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Hay, John C., Liniger, Eric Gerhard, Simonyi, Eva Erika, Lee, Kang-Wook, Hedrick, Jeffrey Curtis, Eckert, Andrew Robert
• Primary Examiner(s): Ghyka, Alexander
• Application Number:
  US09/789,422
• Publication Number:
  US 20020160600A1
• Time in Patent Office: 580 Days
• Field of Search: 438/778, 438/780, 438/781, 438/623
• US Class Current: 438/781
• 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 21/02216 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 21/02282 liquid deposition, e.g. spin-coating, sol-gel techniques, spray coating
• CPC Class Codes: H01L 21/312 Organic layers, e.g. photoresist H01L21/3105, H01L21/32 take precedence; photoresists per se G03C
• CPC Class Codes: H01L 21/3121 Layers comprising organo-silicon compounds
• CPC Class Codes: H01L 21/3122 layers comprising polysiloxane compounds
• CPC Class Codes: H01L 21/3124 layers comprising hydrogen silsesquioxane
• CPC Class Codes: H01L 21/76829 characterised by the formation of thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers

Abstract

A substantially defect-free, low-k dielectric film having improved adhesion is provided by (a) applying a silane coupling agent containing at least one polymerizable group to a surface of a substrate so as to provide a substantially uniform coating of said silane-coupling agent on said substrate; (b) heating the substrate containing the coating of the silane-coupling agent at a temperature of about 90° C. or above so as to provide a surface containing Si—O bonds; (c) rinsing the heated substrate with a suitable solvent that is effective in removing any residual silane-coupling agent; and (d) applying a dielectric material to the rinsed surface containing the Si—O bonds.

Claims

1. A method of fabricating an integrated circuit comprising the steps of:

(a) applying a silane coupling agent containing at least one polymerizable group to a surface of a substrate to provide a substantially uniform coating of said silane-coupling agent on said substrate;

(b) heating said substrate containing said coating of said silane-coupling agent at a temperature of about 90°

C. or above to provide a modified surface layer to said substrate containing Si—

O bonds, said modified surface layer having a greater water contact angle than a non-heated substrate containing a coating of said silane-coupling agent;

(c) rinsing said heated substrate with a suitable solvent that is effective in removing any unreacted silane-coupling agent to provide a modified surface that is substantially free of particular matter; and

(d) applying a dielectric material to said rinsed surface containing said Si—

O.

2. The method of claim 1 wherein said substrate is a Si-containing substrate, a conductive metal, a metal barrier dielectric or an interlevel dielectric layer of an IC having metallic lines and vias formed therein.

3. The method of claim 1 wherein said silane-coupling agent is any silane-containing compound having at least one polymerizable group therein.

4. The method of claim 3 wherein said silane-coupling agent is a compound having the formula:

wherein X is a polymerizable group selected from alkenes, vinyl and alkynes;

R¹ and R² are the same or different and are H, alkyl, alkoxy, alkylester, alkenyl, alkynyl, aryl, cycloalkyl;

R³ is alkyl or a —

C(O)R⁴ radical wherein R⁴ is alkyl;

a and b are the same or different and are 0, 1 or 2, and y is from 1-3, with the proviso that the sum of a+b+y is 3.

5. The method of claim 4 wherein said silane-coupling agent is an alkoxysilane.

6. The method of claim 5 wherein said alkoxysilane is selected from the group consisting of vinyltriacetoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, vinyldiphenylethoxysilane, norborenyltriethoxysilane and trivinyltriethoxysilane.

7. The method of claim 1 wherein said silane-coupling agent is vinyltriacetoxysilane.

8. The method of claim 1 wherein said silane-coupling agent is applied as a concentrated solution.

9. The method of claim 8 wherein said silane-coupling agent is present in said concentrated solution in a concentration of about 0.10% or higher.

10. The method of claim 9 wherein said silane-coupling agent is present in a concentration of from about 0.2% to about 5.0%.

11. The method of claim 10 wherein said silane-coupling agent is present in a concentration of about 2.5%.

12. The method of claim 1 wherein said silane-coupling agent is be applied to the substrate by spin-on deposition, spray coating, dip coating, brushing, evaporation, or dissolution.

13. The method of claim 1 wherein step (b) is carried out for a time period of about 10 seconds or above.

14. The method of claim 1 wherein step (b) is carried out at a temperature of from about 90°

C. to about 200°

C. for a time period of from about 10 to about 300 seconds.

15. The method of claim 1 wherein step (b) is carried out in an inert gas atmosphere.

16. The method of claim 1 wherein said solvent in step (c) is propylene glycol monomethyl ether acetate.

17. The method of claim 1 wherein an optional baking step is conducted after step (c), but prior to step (d).

18. The method of claim 1 wherein said dielectric material has a dielectric constant of about 3.8. or below.

19. The method of claim 1 wherein step (d) includes spin-on coating, chemical solution deposition, chemical vapor deposition (CVD), plasma-assisted CVD, evaporation, and dip coating.

20. The method of claim 1 wherein said dielectric material is a polyimide;

a Si-containing polymer, a benzocyclobutene;

a polynorborane;

a polyarylene ether, a thermostatic polyarylene ether, an aromatic thermosetting resin;

a parylene copolymer;

parylene-F;

polynapthalane;

polytetrafluoronaphthalene;

poly(octafluoro-bis-benzocyclobutene);

Telfon-AF;

fluorinated amorphous carbon;

a Xerogel or a nanoporous silica.

21. The method of claim 1 wherein said dielectric material is methylsilsesquixoane (MSSQ), hydridosilsequixoane or an aromatic thermosetting resin.

22. The method of claim 1 wherein processing steps (a)-(d) are repeated any number of times to provide a multi-level interconnect structure.