Method for Switching Decoupled Plasma Nitridation Processes of Different Doses

• US 20060280876A1
• Filed: 06/09/2005
• Published: 12/14/2006
• Est. Priority Date: 06/09/2005
• Status: Active Grant

• Current Assignee: United Microelectronics Corporation
• Original Assignee: United Microelectronics Corporation
• Inventors: Chen, Chung-Yih, Chan, Shu-Yen, Yen, Ying-Wei, Wang, Yun-Ren, Chiang, Chen-Kuo
• Granted Patent: US 7,601,404 B2
• Time in Patent Office: Days
• US Class Current: 427/569
• CPC Class Codes: H01J 2237/3387 Nitriding
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01L 21/02263 deposition from the gas or vapour phase
• CPC Class Codes: H01L 21/3145 formed by deposition from a gas or vapour

Abstract

A method for switching decoupled plasma nitridation (DPN) processes of different doses, which is able to decrease the switching time, is provided. According to the method, a dummy wafer is inserted into a chamber, a process gas introduced is ignited into plasma, and then a DPN doping process of the next dose is performed on the dummy wafer. The nitrogen concentration of the chamber is thus adjusted rapidly to switch to the DPN process of the next dose. In addition, after several cycles of the above steps are repeated, a dummy wafer is inserted into the chamber, and a complete DPN process of the next dose is performed on the dummy wafer. This process is performed several times before switching to the next DPN process.

Claims

1. A method for switching decoupled plasma nitridation processes of different doses, comprising:

(a) inserting a wafer into a chamber to perform a complete decoupled plasma nitridation process of a first dose on the wafer;

(b) removing the wafer from the chamber;

(c) inserting a dummy wafer into the chamber;

(d) inserting a process gas and RF power to the chamber, and performing a decoupled plasma nitridation doping process of a second dose on the dummy wafer;

(e) removing the dummy wafer from the chamber; and

(f) inserting another wafer to perform a complete decoupled plasma nitridation process of the second dose on the wafer.

2. The method of claim 1, wherein the complete decoupled plasma nitridation process comprises an oxide deposition process, a decoupled plasma nitridation doping process, and an annealing process.

3. The method of claim 1, wherein the dummy wafer inserted in step (c) is treated with a pre-heat process when the first dose is higher than the second dose.

4. The method of claim 3, wherein the pre-heat process is achieved by an oxide deposition process.

5. The method of claim 1, further comprising:

performing a step (f1) between step (e) and step (f) to check nitrogen concentration of the chamber.

6. The method of claim 5, further comprising:

performing a nitrogen concentration adjusting process, which comprises repeating step (e) to step (f1) at least once.

7. The method of claim 1, further comprising:

inserting a second dummy wafer into the chamber, and performing a complete decoupled plasma nitridation process of the second dose on the second dummy wafer before performing step (f).

8. The method of claim 1, wherein the process gas is helium, argon, oxygen, or any mix of the above.

9. The method of claim 1, wherein the flow rate of the process gas is 50-2000 standard cubic centimeters per minute (sccm).

10. The method of claim 1, wherein the range of the RF power is between 100-3000 watts.

11. The method of claim 1, wherein the time range for performing steps (b), (c) and (d) is between 15-750 seconds.

12. A method for switching from a low dose decoupled plasma nitridation process to a high dose decoupled plasma nitridation process, comprising:

(a) inserting a wafer into a chamber to perform a complete low dose decoupled plasma nitridation process on the wafer;

(b) removing the wafer from the chamber;

(c) inserting a dummy wafer into the chamber;

(d) performing a high dose decoupled plasma nitridation doping process on the dummy wafer;

(e) removing the dummy wafer from the chamber; and

(f) inserting another wafer to perform a high dose complete decoupled plasma nitridation process on the wafer.

13. The method of claim 12, wherein the complete decoupled plasma nitridation process comprises an oxide deposition process, a decoupled plasma nitridation doping process, and an annealing process.

14. The method of claim 12, further comprising:

performing a step (f1) between step (e) and step (f) to check nitrogen concentration of the chamber.

15. The method of claim 14, further comprising:

performing a nitrogen concentration adjusting process, which comprises repeating step (e) to step (f1) at least once.

16. The method of claim 12, further comprising:

inserting a second dummy wafer into the chamber, and performing a complete high dose decoupled plasma nitridation process on the second dummy wafer before performing step (f).

17. The method of claim 12, wherein the time range for performing steps (b), (c) and (d) is between 15-750 seconds.