Method for improving process control and film conformality of PECVD film

• US 7,745,346 B2
• Filed: 10/17/2008
• Issued: 06/29/2010
• Est. Priority Date: 10/17/2008
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Varadarajan, Sesha, Sims, James S., Antonelli, Andrew, Hausmann, Dennis, Schravendijk, Bart Van
• Primary Examiner(s): Picardat; Kevin M
• Application Number:
  US12/253,807
• Publication Number:
  US 20100099271A1
• Time in Patent Office: 620 Days
• Field of Search: 438/778, 438/787, 438/788, 438/791, 438/792, 118/723.R, 118/723.VE, 118/723.E
• US Class Current: 438/778
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/402 Silicon dioxide
• CPC Class Codes: C23C 16/515 using pulsed discharges
• CPC Class Codes: C23C 16/52 Controlling or regulating the coating process C23C16/45557, C23C16/279 take precedence
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• 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 21/3185 of siliconnitrides

Abstract

A method for forming a silicon-based dielectric film on a substrate with a single deposition process operation using pulsed plasma enhanced chemical vapor deposition (PECVD) wherein the high frequency radio frequency power of the plasma is pulsed, allows enhanced control, efficiency and product quality of the PECVD process. Pulsing the high frequency RF power of the plasma reduces the deposited film thickness per unit time the high frequency RF power of the plasma is on. This yields silicon-based dielectric films that are both thin and conformal.

Claims

1. A method of forming a silicon-based dielectric film, comprising:

providing a semiconductor device substrate in a deposition chamber; and

,

depositing on the substrate a silicon-based dielectric film by a single process operation using pulsed plasma enhanced chemical vapor deposition wherein the high frequency radio frequency power of the plasma is pulsed at a frequency of 1 Hz to 10 kHz.

2. The method of claim 1, wherein the high frequency radio frequency power of the plasma is pulsed at a frequency of 75 to 500 Hz with a duty cycle of 15 to 99%.

3. The method of claim 1, wherein the high frequency radio frequency power of the plasma is pulsed at a frequency of 500 Hz with a 15% duty cycle.

4. The method of claim 1, wherein the high frequency radio frequency power of the plasma is pulsed with a duty cycle at least long enough to generate a reactive species in a precursor.

5. The method of claim 1, wherein the high frequency radio frequency power of the plasma has a frequency of 2 to 60 MHz.

6. The method of claim 1, wherein the high frequency radio frequency power of the plasma has a frequency of 13.56 Mhz.

7. The method of claim 1, wherein there is a low frequency radio frequency power of the plasma.

8. The method of claim 7, wherein the low frequency radio frequency power of the plasma has a frequency of 50 to 500 kHz.

9. The method of claim 7, wherein the low frequency radio frequency power of the plasma has a frequency of 400 kHz.

10. The method of claim 1, wherein the silicon-based dielectric film is deposited on a photoresist on the semiconductor device substrate.

11. The method of claim 1, wherein the silicon-based dielectric film is deposited on bare silicon on the semiconductor device substrate.

12. The method of claim 1, wherein the silicon-based dielectric film is silicon nitride formed using a silicon precursor and a nitrogen precursor.

13. The method of claim 12 wherein the thickness per deposition time of the silicon nitride is less than 10 nm per minute.

14. The method of claim 12, wherein the silicon precursor is selected from the group consisting of silane and tetraethyl orthosilicate (TEOS) and the nitrogen precursor is selected from the group consisting of ammonia, nitrogen, and hydrazine.

15. The method of claim 12, wherein the silicon precursor is silane and the nitrogen precursor is nitrous oxide.

16. The method of claim 1, wherein the silicon-based dielectric film is silicon oxide formed using a silicon precursor and an oxygen precursor.

17. The method of claim 16, wherein the thickness per deposition time is less than 30 nm per minute.

18. The method of claim 16, wherein the silicon precursor is selected from the group consisting of silane and tetraethyl orthosilicate (TEOS) and the oxygen precursor is selected from the group consisting of nitrous oxide, oxygen, ozone, and water.

19. The method of claim 16, wherein the silicon precursor is tetraethyl orthosilicate (TEOS) and the oxygen precursor is oxygen.

20. The method of claim 1, wherein the high frequency radio frequency power of the plasma is pulsed such that the high frequency radio frequency power is not turned off during the pulses.

21. The method of claim 1, wherein the high frequency radio frequency power of the plasma is pulsed such that the high frequency radio frequency power is increased over a period of time and decreased over a period of time instead of being turned on and off.

22. The method of claim 1 wherein the step coverage of the silicon-based dielectric film is better than the step coverage of a silicon-based dielectric film produced by a plasma enhanced chemical vapor deposition process wherein the high frequency radio frequency power of the plasma is not pulsed.

23. A semiconductor processing apparatus for depositing on a substrate a silicon-based dielectric film comprising:

a chamber having a substrate holder, an inlet for process gases, and a connection to a vacuum source including;

a high frequency radio frequency generator capable of pulsing the high frequency radio frequency power of a plasma; and

a controller configured to execute a set of instructions, the set of instructions including instructions for depositing on the substrate a silicon-based dielectric film by a single process operation using pulsed plasma enhanced chemical vapor deposition wherein the high frequency radio frequency power of the plasma is pulsed, the instructions comprising;

injecting one or more precursor gases into the chamber; and

pulsing the high frequency radio frequency power of the plasma at a frequency of 1 Hz to 10 kHz.