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

• US 7,799,705 B1
• Filed: 01/05/2009
• Issued: 09/21/2010
• 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: Wu, Qingguo, Fu, Haiying, Smith, David C., Mordo, David
• Primary Examiner(s): WILCZEWSKI, MARY A
• Application Number:
  US12/348,791
• Time in Patent Office: 624 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 forming a low-k dielectric material on a substrate, the method comprising:

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

removing the porogen from the dielectric film, thereby creating voids within the dielectric film to form the porous low-k dielectric material.

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

3. The method of claim 2, wherein the structure former precursor is trimethylsilylacetylene (TMSA), bis(trimethylsilyl)acetylene (BTMSA), vinylmethyldimethoxysilane (VMDMOS), methyldimethoxysilaneacetylene (MDMSA), methyldiethoxysilaneacetylene (MDESA), dimethylmethoxysilaneacetylene (DMMSA), dimethylethoxysilaneacetylene (DMESA) methylethoxysilane-di-acetylene (MESDA), divinylmethylethoxysilane (DVMEOS), 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane (VMTS), 1,3,5-trivinyl-1,3,5-triisopropylcyclotrisiloxane (VPTS) and vinyltrimethylsilane (VTMS).

4. The method of claim 2, wherein the structure former precursor is 5-(bicycloheptenyl)methyldimethoxysilane (BMDS), 5-(bicycloheptenyl)triethoxysilane (BTS) or 5-(bicycloheptenyl)diethoxysilaneacetylene (BDS).

5. The method of claim 1, further comprising exposing the dielectric film to a thermal treatment, ultraviolet radiation, e-beam exposure, or a combination thereof.

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

7. The method of claim 1, wherein the dielectric constant of the porous low-k dielectric material is less than or equal to about 2.5.

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

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

10. The method of claim 1 wherein the hardness of the low-k dielectric material is greater than about 1.0 GPa.

11. The method of claim 1, wherein the dielectric constant of the porous low-k dielectric material is less than or equal to about 2.7 and the hardness is greater than about 1.0 GPa.

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

13. A method of forming a low-k dielectric material on a substrate, the method comprising:

forming a dielectric film on the substrate, the dielectric film comprising a porogen and a structure former, wherein the structure former has one or more carbon-carbon double or triple bonds and wherein the structure former and porogen are both obtained from a single structure former precursor; and

removing the porogen from the dielectric film, thereby creating voids within the dielectric film to form the porous low-k dielectric material.

14. The method of claim 13, 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), 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane (VMTS), 1,3,5-trivinyl-1,3,5-triisopropylcyclotrisiloxane (VPTS) and vinyltrimethylsilane (VTMS).

15. The method of claim 13, wherein the structure former precursor is 5-(bicycloheptenyl)methyldimethoxysilane (BMDS), 5-(bicycloheptenyl)triethoxysilane (BTS) or 5-(bicycloheptenyl)diethoxysilaneacetylene (BDS).

16. The method of claim 13, further comprising exposing the dielectric film to a thermal treatment, ultraviolet radiation, e-beam exposure, or a combination thereof.

17. The method of claim 13, wherein the dielectric constant of the porous low-k dielectric material is less than or equal to about 2.7.

18. The method of claim 13, wherein the dielectric constant of the porous low-k dielectric material is less than or equal to about 2.5.

19. The method of claim 13, wherein the hardness of the low-k dielectric material is greater than about 1.0 GPa.

20. The method of claim 13, wherein the dielectric constant of the porous low-k dielectric material is less than or equal to about 2.7 and the hardness is greater than about 1.0 GPa.