METHOD FOR CHARACTERIZING LINE WIDTH ROUGHNESS (LWR) OF PRINTED FEATURES

• US 20080055597A1
• Filed: 08/29/2006
• Published: 03/06/2008
• Est. Priority Date: 08/29/2006
• Status: Abandoned Application

• Current Assignee: United Microelectronics Corporation
• Original Assignee: United Microelectronics Corporation
• Inventors: Lin, Benjamin Szu-Min, Hung, Wen-Kai, Sun, Jie-Wei
• Application Number:
  US11/467,930
• Publication Number:
  US 20080055597A1
• Time in Patent Office: Days
• US Class Current: 356/369
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G01N 2021/213 Spectrometric ellipsometry
• CPC Class Codes: G01N 21/211 Ellipsometry optical thickness measurement G01B11/06
• CPC Class Codes: G01N 21/956 Inspecting patterns on the surface of objects contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10

Abstract

A method for characterizing line width roughness of printed features is provided. A wafer having thereon a plurality of gratings formed within a test key region is prepared. The wafer is transferred to a spectroscopic ellipsometry tool having a light source, a detector and a computer. A polarized light beam emanated from the light source is directed onto the gratings. Spectrum data of reflected light is measured and recorded. The spectrum data is compared to a library linked to the computer in real time. The library contains a plurality of contact-hole model based spectra created by incorporating parameter values that describes the line width roughness. The spectrum data is matched with the contact-hole model based spectra, thereby determining the parameter values.

Claims

1. A method for characterizing line width roughness of printed features, comprising:

preparing a wafer having thereon a plurality of gratings formed within a test key region;

transferring said wafer to an optical tool comprising a light source, a detector and a computer;

directing a polarized light beam emanated from said light source onto said gratings;

measuring and recording a spectrum data of reflected light;

comparing said spectrum data to a library linked to said computer, wherein said library contains a plurality of contact-hole model based spectra created by incorporating parameter values that describes said line width roughness; and

matching said spectrum data with said contact-hole model based spectra, thereby determining said parameter values.

2. The method according to claim 1 wherein said optical tool comprises a spectroscopic ellipsometry tool and a reflectometry tool.

3. The method according to claim 1 wherein said parameter values comprise a diameter on x-axis of contact hole pattern that decides line critical dimension.

4. The method according to claim 1 wherein said parameter values comprise a diameter on y-axis of a contact hole pattern.

5. The method according to claim 1 wherein said parameter values comprise rectangularity r.

6. The method according to claim 1 wherein said parameter values comprise ellipticity (a/b), a first pitch on x-axis, a second pitch on y-axis, which decide line edge roughness, wherein a is diameter on x-axis of contact hole pattern and b is diameter on y-axis of contact hole pattern.

7. The method according to claim 1 wherein said test key region is located on anywhere within a shot, with its size larger than light source.

8. The method according to claim 1 wherein said test key region is located on a scribe line.

9. The method according to claim 1 wherein said gratings are 50 μ

m×

50 μ

m in size.

10. The method according to claim 1 wherein said gratings are repeating line/space features of uniform period.

11. The method according to claim 1 wherein said gratings have a line/space ratio less than 1/13.

12. The method according to claim 1 wherein said gratings have a line/space ratio of 80/100 nm (180 nm pitch).

13. The method according to claim 1 wherein said gratings are resist lines.

14. The method according to claim 1 wherein said light source comprises a broadband light source.

15. A method for characterizing line width roughness of printed features, comprising:

preparing a wafer having thereon a plurality of gratings formed within a test key region;

transferring said wafer to an optical tool comprising a light source, a detector and a computer;

directing a polarized light beam emanated from said light source onto said gratings;

measuring and recording a spectrum data of reflected light;

comparing said spectrum data to a library linked to said computer in real time, wherein said library contains a plurality of modeled spectra created by incorporating parameter values that describes said line width roughness, wherein said parameter values comprise a diameter “

a”

on x-axis of a contact hole pattern that decides line critical dimension, a diameter “

b”

on y-axis of said contact hole pattern, rectangularity r, ellipticity (a/b), a first pitch on said x-axis, and a second pitch on said y-axis; and

matching said spectrum data with said modeled spectra, thereby determining said parameter values.

16. The method according to claim 15 wherein said optical tool comprises a spectroscopic ellipsometry tool and a reflectometry tool.

17. The method according to claim 15 wherein said test key region is located on a scribe line.

18. The method according to claim 15 wherein said gratings are 50 μ

m×

50 μ

m in size.

19. The method according to claim 15 wherein said gratings are repeating line/space features of uniform period.

20. The method according to claim 15 wherein said gratings are resist lines.

21. The method according to claim 15 wherein said light source comprises a broadband light source.