Methods for producing low stress porous low-k dielectric materials using precursors with organic functional groups

• US 7,473,653 B1
• Filed: 06/18/2007
• Issued: 01/06/2009
• Est. Priority Date: 03/31/2003
• Status: Expired due to Fees

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Smith, David C., Wu, Qingguo, Fu, Haiying, Mordo, David
• Primary Examiner(s): WILCZEWSKI, MARY A
• Application Number:
  US11/764,750
• Time in Patent Office: 568 Days
• Field of Search: 427/255.28, 427/255.18, 427/255.27, 427/255.37, 427/255.393, 427/387, 427/551, 427/553, 427/557, 438/507, 438/509, 438780-782, 438/787, 438/788, 438/789, 438/790, 438/783, 438/784
• 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 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• 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 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/31695 Deposition of porous oxides or porous glassy oxides or oxide based porous glass

Abstract

Methods of preparing a low stress porous low-k dielectric material on a substrate are provided. The methods involve the use of a structure former precursor and/or porogen precursor with one or more organic functional groups. In some cases, the structure former precursor has carbon-carbon double or triple bonds. In other cases, one or both of the structure former precursor and porogen precursor has one or more bulky organic groups. In other cases, the structure former precursor has carbon-carbon double or triple bonds and one or both of the structure former precursor and porogen precursor has one or more bulky organic groups. Once the precursor film is formed, the porogen is removed, leaving a porous low-k dielectric matrix with high mechanical strength. Different types of structure former precursors and porogen precursors are described. The resulting low stress low-k porous film may be used as a low-k dielectric film in integrated circuit manufacturing applications.

Claims

1. A method of preparing a porous low-k dielectric material on a substrate, the method comprising:

forming a precursor film on the substrate, the precursor film comprising a porogen and a structure former, wherein the structure former has one or more carbon-carbon double or triple aliphatic bonds; and

treating the precursor film to facilitate removing the porogen from the precursor film and thereby creating voids within the dielectric material to form the porous low-k dielectric material.

2. The method of claim 1, wherein the structure former comprises silicon.

3. The method of claim 1, wherein the precursor film is produced by co-depositing a structure former precursor with a porogen precursor.

4. The method of claim 3, wherein the structure former precursor is a molecule containing at least one silicon atom bonded to a carbon-carbon double bond or a carbon-carbon triple bond.

5. The method of claim 3, wherein the structure former precursor is trimethylsilylacetylene (TMSA), bis(trimethylsilyl)acetylene (BTMSA), vinylmethyldimethoxysilane (VMDMOS), methyldimethoxysilaneacetylene (MDMSA), methyldiethoxysilaneacetylene (MDESA), dimethylmethoxysilaneacetylene (DMMSA), dimethylethoxysilaneacetylene (DMESA) or methylethoxysilane-di-acetylene (MESDA), divinylmethylethoxysilane (DVMEOS).

6. The method of claim 3, wherein the structure former precursor has a bulky organic functional group.

7. The method of claim 6, wherein the structure former precursor is 5-(bicycloheptenyl)methyldimethoxysilane (BMDS), 5-(bicycloheptenyl)triethoxysilane (BTS) or 5-(bicycloheptenyl)diethoxysilaneacetylene (BDS).

8. The method of claim 3, wherein the porogen precursor is a polyfunctional cyclic non-aromatic compound.

9. The method of claim 8, wherein the polyfunctional cyclic non-aromatic compound is 5-ethylidene-2-norbornene (ENB), 8,8-dimethylfulvene (DMF) or beta-pinene (BP).

10. The method of claim 1, wherein the structure former and porogen are both obtained from a structure former precursor.

11. The method of claim 10, wherein the structure former precursor has a bulky organic group.

12. The method of claim 11, wherein the structure former precursor is 5-(bicycloheptenyl)methyldimethoxysilane (BMDS), 5-(bicycloheptenyl)triethoxysilane (BTS) or 5-(bicycloheptenyl)diethoxysilaneacetylene (BDS).

13. The method of claim 1, wherein the precursor film is formed by a chemical vapor deposition process.

14. The method of claim 13, wherein the deposition temperature during chemical vapor deposition ranges between about 25 and about 450 degrees Celsius.

15. The method of claim 1, wherein the precursor film is formed by a spin-on technique.

16. The method of claim 1, wherein treating the precursor film to facilitate removing the porogen from the precursor film involves a thermal treatment, ultraviolet radiation exposure, e-beam exposure, or a combination thereof.

17. The method of claim 1, wherein the dielectric constant of the porous low-k dielectric material is less than about 2.7.

18. The method of claim 1, wherein the tensile stress of the porous low-k dielectric material is less than about 55 MPa.