Method for controlling accuracy and repeatability of an etch process

• US 7,094,613 B2
• Filed: 10/21/2003
• Issued: 08/22/2006
• Est. Priority Date: 10/21/2003
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Mui, David, Liu, Wei, Sasano, Hiroki
• Primary Examiner(s): Norton, Nadine G.
• Assistant Examiner(s): CHEN, ERIC BRICE
• Application Number:
  US10/690,318
• Publication Number:
  US 20050085090A1
• Time in Patent Office: 1,036 Days
• Field of Search: 430/5, 438/5, 438/9, 438/14, 438/16, 438/714, 438719-721, 438/723, 438/724, 438/740, 438/743, 438/744, 216/60, 216/67, 216/70
• US Class Current: 438/9
• CPC Class Codes: H01L 21/02071 the processing being a delineation, e.g. RIE, of conductive layers
• CPC Class Codes: H01L 21/31138 by dry-etching
• CPC Class Codes: H01L 21/32137 of silicon-containing layers
• CPC Class Codes: H01L 21/32139 using masks

Abstract

Embodiments of the invention generally relate to a method for etching in a processing platform (e.g. a cluster tool) wherein robust pre-etch and post-etch data may be obtained in-situ. The method includes the steps of obtaining pre-etched critical dimension (CD) measurements of a feature on a substrate, etching the feature; treating the etched substrate to reduce and/or remove sidewall polymers deposited on the feature during etching, and obtaining post-etched CD measurements. The CD measurements may be utilized to adjust the etch process to improved the accuracy and repeatability of device fabrication.

Claims

1. A method for controlling accuracy and repeatability of an etch process, comprising:

(a) providing a batch of substrates, each substrate having a patterned mask formed on a film stack comprising at least one material layer;

(b) measuring dimensions of elements of the patterned mask on at least one substrate of the batch of substrates;

(c) trimming the patterned mask on the at least one substrate using a process recipe based on the measurements performed at step (b), then;

(d) etching the at least one material layer on the at least one substrate;

(e) measuring a thickness of post-etch residue and at least one of compacting or removing at least a portion of the post-etch residue formed on sidewalls of the etched structures based on the thickness of the post-etch residue;

(f) measuring dimensions of etched structures formed on the at least one substrate during step (d); and

(g) adjusting the process recipe of step (c) or/and the process recipe of step (d);

based on the measurements performed at step (f).

2. The method of claim 1 wherein the steps (b) and (f) use an optical measuring technique.

3. The method of claim 2 wherein the optical measuring technique is a scatterometric measuring technique.

4. The method of claim 1 wherein the steps (b) through (f) are performed using processing modules of a single substrate processing system.

5. The method of claim 1 wherein the step (g) further comprises:

modifying a time duration or process parameters for trimming the patterned mask.

6. The method of claim 1 wherein the step (g) further comprises:

modifying a time duration or process parameters for etching the material layer.

7. The method of claim 1 further comprising:

thinning the post-etch residue to a thickness of less than about 10 nm.

19. The method of claim 1, wherein the step (e) further comprises:

measuring a critical dimension of a feature is done in addition to measuring the thickness of the post-etch residue.

8. A method for controlling accuracy and repeatability during formation of a gate structure of a field effect transistor, comprising:

(a) providing a batch of substrates, each substrate having a patterned mask formed on a gate electrode layer of the gate structure;

(b) measuring dimensions of elements of the patterned mask on at least one substrate of the batch of substrates;

(c) trimming the patterned mask on the at least one substrate using a process recipe based on the measurements performed at step (b), then;

(d) etching the gate electrode layer on the at least one substrate;

(e) measuring a thickness of post-etch residue and at least one of compacting or removing at least the portion of post-etch residue formed on sidewalls of the etched structures based on the thickness of the post-etch residue;

(f) measuring dimensions of etched gate electrode structures formed on the at least one substrate during step (d); and

(g) adjusting the process recipe of step (c) or/and the process recipe of step (d) based on the measurements performed at step (f).

9. The method of claim 8 wherein the steps (b) and (f) use an optical measuring technique.

10. The method of claim 9 wherein the optical measuring technique is a scatterometric measuring technique.

11. The method of claim 8 wherein the steps (b) through (f) are performed using processing modules of a single substrate processing system.

12. The method of claim 8 wherein the step (g) further comprises:

modifying a time duration or process parameters for trimming the patterned mask.

13. The method of claim 8 wherein the step (g) further comprises:

modifying a time duration or process parameters for etching the material layer.

14. The method of claim 8 wherein the gate electrode layer comprises doped polysilicon.

15. The method of claim 8 wherein the step (d) further comprises:

providing HBr and Cl₂ at a flow ratio HBr;

Cl₂ in a range from 1;

15 to 15;

1.

16. The method of claim 8 further comprising:

thinning the post-etch residue to a thickness of less than about 10 nm.

17. The method of claim 15 further comprising:

using a plasma comprising one or more gases selected from the group consisting of nitrogen (N₂), oxygen (O₂) and hydrogen (H₂).

18. The method of claim 17 further comprising:

providing nitrogen (N₂) and hydrogen (H₂) at a N₂;

H₂ flow ratio in a range from 3;

1 to 100% of N₂;

maintaining the substrate at a temperature between about 200 and 350 degrees Celsius;

applying power to an inductively coupled power source between about 1000 and 7000 W; and

maintaining a chamber pressure between about 500 and 2000 mTorr.

20. The method of claim 8, wherein the step (e) further comprises:

measuring a critical dimension of a feature is done in addition to measuring the thickness of the post-etch residue.