Methods and apparatus for measuring thickness of etching residues on a substrate

• US 7,817,289 B2
• Filed: 07/23/2008
• Issued: 10/19/2010
• Est. Priority Date: 07/23/2007
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Yang, Susie Xiuru
• Primary Examiner(s): Toatley, Jr.; Gregory J
• Assistant Examiner(s): Underwood; Jarreas C.
• Application Number:
  US12/178,567
• Publication Number:
  US 20090027695A1
• Time in Patent Office: 818 Days
• Field of Search: 56600-640
• US Class Current: 356/630
• CPC Class Codes: G01B 11/0625 with measurement of absorption or reflection
• CPC Class Codes: H01J 37/32935 Monitoring and controlling tubes by information coming from the object and/or discharge
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14

Abstract

A method of determining a thickness of a residue layer on a substrate includes: (1) taking a first set of optical scatterometry measurements on the substrate after an etching procedure; (2) taking a second set of optical scatterometry measurements on the substrate after a post-etch cleaning procedure; (3) calculating a difference measurement between the first set and second set of optical scatterometry measurements; (4) determining an initial thickness measurement of the residue layer based on the difference measurement by applying a first dispersion model; and (5) adjusting the initial thickness measurement by applying a second dispersion model based on a material composition of the residue layer. Numerous other aspects are provided.

Claims

1. A method of determining a thickness of a residue layer on a substrate comprising:

performing a first set of optical scatterometry measurements on the substrate after an etching procedure;

performing a second set of optical scatterometry measurements on the substrate after a post-etch cleaning procedure;

calculating a difference measurement between the first set and second set of optical scatterometry measurements; and

determining an initial thickness measurement of the residue layer based on the difference measurement by applying a first dispersion model.

2. The method of claim 1, wherein the first dispersion model comprises a silicon dioxide optical dispersion model.

3. The method of claim 1 wherein the first set of optical scatterometry measurements measures at least one of critical dimension, trench width and trench profile.

4. The method of claim 3 wherein the second set of optical scatterometry measurements measures at least one of critical dimension, trench width and trench profile.

5. The method of claim 1 wherein the first and second sets of optical scatterometry measurements measure at least one of intensity, phase and polarization of light scattered from the substrate.

6. A method of determining a thickness of a residue layer on a substrate comprising:

performing a first set of optical scatterometry measurements on the substrate after an etching procedure;

performing a second set of optical scatterometry measurements on the substrate after a post-etch cleaning procedure;

calculating a difference measurement between the first set and second set of optical scatterometry measurements;

determining an initial thickness measurement of the residue layer based on the difference measurement by applying a first dispersion model; and

adjusting the initial thickness measurement by applying a second dispersion model based on a material composition of the residue layer.

7. The method of claim 6, wherein the first dispersion model comprises a silicon dioxide optical dispersion model.

8. The method of claim 6, wherein the second dispersion model comprises at least one of an organic material dispersion model and a dielectric dispersion model.

9. The method of claim 6 wherein the first set of optical scatterometry measurements measures at least one of critical dimension, trench width and trench profile.

10. The method of claim 9 wherein the second set of optical scatterometry measurements measures at least one of critical dimension, trench width and trench profile.

11. The method of claim 6 wherein the first and second sets of optical scatterometry measurements measure at least one of intensity, phase and polarization of light scattered from the substrate.

12. A method of determining a thickness of a residue layer on a substrate comprising:

performing a first set of optical scatterometry measurements on the substrate after an etching procedure;

performing a second set of optical scatterometry measurements on the substrate after a post-etch cleaning procedure;

calculating a difference measurement between the first set and second set of optical scatterometry measurements;

determining an initial thickness measurement of the residue layer based on the difference measurement by applying a first dispersion model; and

adjusting the initial thickness measurement by applying a second dispersion model based on a material composition of the residue layer;

wherein the first dispersion model comprises a silicon dioxide optical dispersion model; and

wherein the second dispersion model comprises at least one of an organic material dispersion model and a dielectric dispersion model.

13. The method of claim 12 wherein the first and second sets of optical scatterometry measurements measure at least one of intensity, phase and polarization of light scattered from the substrate.