Method for forming a high density dielectric film by chemical vapor deposition

• US 20070020953A1
• Filed: 07/21/2005
• Published: 01/25/2007
• Est. Priority Date: 07/21/2005
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Lin, Chih-Lung, Chou, You-Hua, Tsai, Cheng-Yuan
• Granted Patent: US 7,314,838 B2
• Time in Patent Office: Days
• US Class Current: 438/778
• CPC Class Codes: C23C 16/45523 Pulsed gas flow or change of composition over time
• CPC Class Codes: C23C 16/45557 Pulsed pressure or control pressure
• CPC Class Codes: C23C 16/50 using electric discharges generation and control of plasma in discharge tubes for surface treatment H01J37/32, H01J37/34
• 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 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/76801 characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing

Abstract

A method for forming a high density dielectric film by chemical vapor deposition. The method comprises: (a) a substrate is provided in a processing chamber; (b) a first gas is introduced into the processing chamber with a first pressure and adsorbed on the substrate, wherein the first gas comprises silicon-containing or carbon-containing gas; (c) the first gas is stopped, and the first pressure is lowered to a second pressure; (d) a second gas is introduced into the processing chamber with a third pressure, and forced to react with the first gas absorbed on the substrate and remained in the processing chamber, wherein the second gas comprises oxidizer or reduction agent; (e) the steps (b)˜(d) are repeated until a high density dielectric film is formed on the substrate.

Claims

1. A method for forming a high density dielectric film by chemical vapor deposition, comprising:

(a) providing a substrate;

(b) flowing a first gas at a first pressure to adsorb on the substrate, wherein the first gas comprises silicon-containing or carbon-containing gas;

(c) halting the flow of the first gas and lowering the first pressure to a second pressure;

(d) flowing a second gas to a third pressure and reacting the second gas with the first gas, wherein the second gas comprises oxidizer or reduction agent; and

(e) repeating steps (b)˜

(d) to form a high density dielectric film on the substrate.

2. The method as claimed in 1, wherein a method for reacting the second gas with the first gas in the step (d) comprises generating a plasma by a radio frequency (RF) power of 5˜

300 watts.

3. The method as claimed in 1, wherein the high density dielectric film has a thickness of no more than 100 nm.

4. The method as claimed in 1, wherein the steps (b)˜

(d) are performed at a temperature of 100˜

400°

C.

5. The method as claimed in 1, wherein the steps (b)˜

(d) are performed at a temperature of 150˜

350°

C.

6. The method as claimed in 1, wherein the first pressure is not more than 3 Torr.

7. The method as claimed in 1, wherein the first pressure is between 1 Torr to 0.1 mTorr.

8. The method as claimed in 1, wherein the ratio between the first pressure and the second pressure is from 2:

1 to 100;

1.

9. The method as claimed in 1, wherein the third pressure is between 2 Torr to 0.1 mTorr.

10. The method as claimed in 1, wherein the first gas comprises SiH₄, Si₂H₆, SiH₃CH₃, TEOS, TMCTS, OMCTS, methyl-silane, dimethyl-silane, 3MS, 4MS, TMDSO, TMDDSO, DMDMS or combinations thereof.

11. The method as claimed in 1, wherein the second gas comprises N₂, N₂O, NO, NH₃, NF₃, O₂, H₂, O₃, CO, CO₂, or combinations thereof.

12. A method for fabricating a semiconductor device, comprising:

(a) providing a substrate;

(b) flowing a first gas to a first pressure to adsorb on the substrate, wherein the first gas comprises silicon-containing or carbon-containing gas;

(c) halting the flow of the first gas and lowering the first pressure to a second pressure;

(d) flowing a second gas to a third pressure and reacting the second gas with the first gas, wherein the second gas comprises oxidizer or reduction agent;

(e) repeating steps (b)˜

(d) to form a first high density dielectric film on the substrate; and

(f) simultaneously flowing the first gas and second gas to a fourth pressure of more than 3 Torr, and reacting the first gas and the second gas to form a low-k dielectric layer on the first high density dielectric film.

13. The method as claimed in 12, wherein a method for reacting the second gas with the first gas in the step (d) comprises generating a plasma by a first radio frequency (RF) power.

14. The method as claimed in 13, wherein a method for reacting the first gas with the second gas in the step (f) comprises generating a plasma by a second radio frequency (RF) power.

15. The method as claimed in 14, wherein the ratio between the second RF power is 300˜

1000 watts.

16. The method as claimed in 14, wherein the ratio between the first RF power and the second RF power is from 2:

1 to 50;

1.

17. The method as claimed in 12, wherein the ratio between the first pressure and the second pressure is from 2:

1 to 100;

1.

18. The method as claimed in 12, wherein the ratio between the first pressure and the fourth pressure is from 1:

4 to 1;

1000.

19. The method as claimed in 12, wherein the ratio between the third pressure and the fourth pressure is from 1:

4 to 1;

1000.

20. The method as claimed in 12, wherein the pressure ratio between the first gas and the second gas is from 1:

10 to 10;

1.

21. The method as claimed in 14, after the step (f), further comprising:

(g) flowing the first gas to a fifth pressure to adsorb on the low-k dielectric layer;

(h) halting the flow of the first gas and lowering the fifth pressure to a sixth pressure;

(i) flowing the second gas to a seventh pressure and reacting the second gas with the first gas; and

(j) repeating steps (g)˜

(i) to form a second high density dielectric film on the low-k dielectric layer.

22. The method as claimed in 21, wherein a method for reacting the second gas with the first gas in the step (i) comprises generating a plasma by a third radio frequency (RF) power.

23. The method as claimed in 22, wherein the ratio between the third RF power and the second RF power is from 2:

1 to 50;

1.

24. The method as claimed in.21, wherein the ratio between the fifth pressure and the sixth pressure is from 2:

1 to 100;

1.

25. The method as claimed in 21, wherein the ratio between the fifth pressure and the fourth pressure is from 1:

4 to 1;

1000.

26. The method as claimed in 21, wherein the ratio between the seventh pressure and the fourth pressure is from 1:

4 to 1;

1000.

27. The method as claimed in 21, wherein the steps (d), (f), and (i) are performed in the same process chamber.