Method of controlling critical dimension microloading of photoresist trimming process by selective sidewall polymer deposition

• US 6,911,399 B2
• Filed: 09/19/2003
• Issued: 06/28/2005
• Est. Priority Date: 09/19/2003
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Mui, David, Liu, Wei
• Primary Examiner(s): Fourson, George
• Assistant Examiner(s): Kebede, Brook
• Application Number:
  US10/665,934
• Publication Number:
  US 20050064719A1
• Time in Patent Office: 648 Days
• Field of Search: 438/689, 438/708, 438/710, 438/712, 438/714, 438/717, 438/751, 438/694, 438/706, 438/707, 438/711, 438/725, 716/19, 716/21, 430/269, 430/299
• US Class Current: 438/725
• CPC Class Codes: G03F 7/40 Treatment after imagewise removal, e.g. baking
• CPC Class Codes: H01L 21/0274 Photolithographic processes
• CPC Class Codes: H01L 21/31138 by dry-etching

Abstract

A method for trimming photoresist features on a semiconductor substrate in a processing system. The method utilizes a process gas mixture comprising a hydrocarbon gas, an oxygen gas and an inert gas. The critical dimension (CD) microloading of the dense and the isolated regions can be eliminated and the photoresist trimming rate can also be reduced to enable better critical dimension (CD) control.

Claims

1. A method for trimming photoresist features on a semiconductor substrate in a plasma processing system, comprising:

placing a substrate with a patterned photoresist layer having at least one element with a first prescribed width on the substrate in the plasma processing system;

supplying to the process chamber a process gas mixture comprising a hydrocarbon gas, an oxygen gas, and an inert gas, or a process gas mixture comprising a halogenated hydrocarbon gas, an oxygen gas, and an inert gas, or a mixture thereof and disassociating the process gas mixture to etch the patterned photoresist layer.

2. The method of claim 1 further comprising:

terminating the etch process to leave the patterned photoresist layer with at least one element with a second prescribed width on the substrate.

3. The method of claim 1 wherein the halogenated hydrocarbon gas is CHF₃.

4. The method of claim 3 wherein the hydrocarbon gas is CH₄.

5. The method of claim 1 wherein the flow rate of the hydrocarbon gas is between about 20 sccm to about 400 sccm and the flow rate ratio of hydrocarbon gas to oxygen gas is between about 1 to about 20.

6. The method of claim 1 wherein the oxygen flow rate is between about 5 scorn to about 100 sccm.

7. The method of claim 1 wherein the inert gas is argon.

8. The method of claim 1 wherein flow rate of the inert gas is between about 20 sccm to about 400 sccm and the flow rate ratio of inert gas to oxygen gas is between about 1 to about 20.

9. The method of claim 1 wherein the process pressure is between about 2 mTorr to about 50 mTorr.

10. The method of claim 1 wherein the source power is between 200 watts to 1500 watts.

11. The method of claim 1 wherein the bias power is between 0 watts to 400 watts.

12. The method of claim 1 wherein the substrate has a patterned photoresist layer having patterns of dense regions and isolated regions.

13. The method of claim 12 wherein the pattern density of the dense region is greater than 20%.

14. The method of claim 12 wherein the pattern density of the isolated region is less than 10%.

15. The method of claim 12 wherein the etch rates of the dense regions and the isolated regions are controlled by the ratio of hydrocarbon gas to oxygen gas.

16. The method of claim 1, wherein the etch rate of the photoresist layer is less than 1 nm/second.

17. The method of claim 1, wherein the photoresist is a DUV resist.