Hermetic cap layers formed on low-k films by plasma enhanced chemical vapor deposition

• US 20050282404A1
• Filed: 06/21/2004
• Published: 12/22/2005
• Est. Priority Date: 06/21/2004
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Kim, Bok Hoen, Yim, Kang Sub, Nguyen, Vu Ngoc Tran
• Granted Patent: US 7,285,503 B2
• Time in Patent Office: Days
• US Class Current: 438/788
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02315 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/0276 using an anti-reflective coating anti-reflective coating for lithography in general G03F7/09
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: H01L 21/76801 characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing
• CPC Class Codes: H01L 21/76807 for dual damascene structures
• 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
• CPC Class Codes: H01L 21/76831 in via holes or trenches, e.g. non-conductive sidewall liners

Abstract

A method of forming a cap layer over a dielectric layer on a substrate including forming a plasma from a process gas including oxygen and tetraethoxysilane, and depositing the cap layer on the dielectric layer, where the cap layer comprises a thickness of about 600 Å or less, and a compressive stress of about 200 MPa or more. Also, a method of forming a cap layer over a dielectric layer on a substrate including forming a process gas by flowing together about 200 mgm to about 8000 mgm of tetraethoxysilane, about 2000 to about 20000 sccm of oxygen (O₂), and about 2000 sccm to about 20000 sccm of carrier gas, generating a plasma from the process gas, where one or more RF generators supply about 50 watts to about 100 watts of low frequency RF power to the plasma, and about 100 watts to about 600 watts of high frequency RF power to the plasma, and depositing the cap layer on the dielectric layer.

Claims

1. A method of forming a cap layer over a dielectric layer on a substrate, the method comprising:

forming a plasma from a process gas comprising oxygen and a silicon containing precursor; and

depositing the cap layer on the dielectric layer, wherein the cap layer comprises a thickness of about 600 Å

or less, and a compressive stress of about 200 MPa or more.

2. The method of claim 1, wherein the thickness of the cap layer is about 200 Å

to about 600 Å

.

3. The method of claim 1, wherein the thickness of the cap layer is about 200 Å

or less.

4. The method of claim 1, wherein the compressive stress of the cap layer is about 200 MPa to about 300 MPa.

5. The method of claim 1, wherein the compressive stress of the cap layer is about 300 MPa or more.

6. The method of claim 1, wherein the substrate comprises a 200 mm wafer.

7. The method of claim 6, wherein the forming of the plasma comprises:

striking the plasma using one or more RF generators, wherein the RF generators supply a low frequency RF power of about 50 watts, and supply a high frequency RF power from about 100 watts to about 300 watts.

8. The method of claim 7, wherein the low frequency power is about 350 to about 550 kHz, and the high frequency power is about 10 to about 15 MHz.

9. The method of claim 1, wherein the substrate comprises a 300 mm wafer.

10. The method of claim 9, wherein the forming of the plasma comprises:

striking the plasma using one or more RF generators, wherein the RF generators supply a low frequency RF power of about 100 watts, and supply a high frequency RF power from about 200 watts to about 600 watts.

13. The method of claim 1, wherein the method further comprises depositing a bottom antireflective coating (BARC) layer on the cap layer, wherein the cap layer prevents materials from the BARC layer from contaminating the dielectric layer.

11. The method of clam 1, wherein the cap layer is formed at a rate of about 875 Å

/min or less.

12. The method of clam 1, wherein the silicon containing precursor comprises silane, tetraethoxysilane, or octamethylcyclotetrasiloxane.

14. A method of forming a cap layer over a dielectric layer on a substrate, the method comprising:

forming a process gas by flowing together about 200 mgm to about 8000 mgm of a silicon containing precursor, about 2000 to about 20000 sccm of oxygen (O₂), and about 2000 sccm to about 20000 sccm of carrier gas;

generating a plasma from the process gas, wherein one or more RF generators supply about 50 watts to about 100 watts of low frequency RF power to the plasma, and about 100 watts to about 600 watts of high frequency RF power to the plasma; and

depositing the cap layer on the dielectric layer, wherein the cap layer has a compressive stress of 200 MPa or more.

15. The method of claim 14, wherein the compressive stress of the cap layer is about 300 MPa or more.

16. The method of claim 14, wherein the cap layer has a thickness of about 600 Å

or less.

17. The method of claim 14, wherein the cap layer has a density of 2.22 g/cm³ or more.

18. The method of claim 14, wherein the cap layer comprises undoped silicate glass.

19. The method of claim 14, wherein the dielectric layer is a low-κ

dielectric layer comprising silicon and carbon.

20. The method of claim 19, wherein the dielectric layer is a silicon-oxygen-carbon (Si—

O—

C) layer.

21. The method of claim 14, wherein the dielectric layer has a wet etch rate ratio (WERR) of 2.5:

1 or more.

22. The method of claim 14, wherein the carrier gas is helium.

23. The method of claim 14, wherein the silicon containing precursor comprises silane, tetraethoxysilane, or octamethylcyclotetrasiloxane.

24. A system for forming a cap layer over a dielectric layer on a substrate, the system comprising:

a housing configured to form a processing chamber;

a gas distribution system to flow about 200 mgm to about 8000 mgm of a silicon containing precursor, about 2000 to about 20000 sccm of oxygen (O₂), and about 2000 sccm to about 20000 sccm of carrier gas through a gas distribution faceplate and into the processing chamber;

a plasma generation system configured to form a plasma within said processing chamber, wherein said plasma generation system comprises one or more RF generators that supply about 50 watts to about 100 watts of low frequency RF power to the plasma, and about 100 watts to about 600 watts of high frequency RF power to the plasma; and

a substrate holder configured to hold the substrate about 350 to about 450 mils from the gas distribution faceplate within the processing chamber, wherein the cap layer formed has a thickness of about 600 Å

or less.

25. The system of claim 24, wherein the cap layer has a compressive stress of about 200 MPa or more.

26. The system of claim 24, wherein the dielectric layer is a low-κ

dielectric layer comprising silicon and carbon.

27. The system of claim 24, wherein the cap layer comprises undoped silicate glass.

28. The system of claim 24, wherein the silicon containing precursor comprises silane, tetraethoxysilane, or octamethylcyclotetrasiloxane.