Method and system for measuring in patterned structures

• US 6,650,424 B2
• Filed: 12/07/2001
• Issued: 11/18/2003
• Est. Priority Date: 12/07/2000
• Status: Active Grant

• Current Assignee: Nova Measuring Instruments Limited (Honeywell International Inc.)
• Original Assignee: Nova Measuring Instruments Limited (Honeywell International Inc.)
• Inventors: Brill, Boaz, Finarov, Moshe
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): Nguyen, Sang H.
• Application Number:
  US10/005,118
• Publication Number:
  US 20020090744A1
• Time in Patent Office: 711 Days
• Field of Search: 356/604, 356/614, 356/625, 356/630, 356/635, 356/388, 356/394, 356/496, 356/503, 250/559.19, 250/559.44, 250/310, 430/8, 430/70
• US Class Current: 356/601
• CPC Class Codes: G01B 15/00 Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons characterised by the use of optical techniques G01B9/00, G01B11/00
• CPC Class Codes: G01N 21/47 Scattering, i.e. diffuse reflection G01N21/25, G01N21/41 take precedence G01N21/55 takes precedence
• 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
• CPC Class Codes: G01N 23/225 using electron or ion
• CPC Class Codes: G03F 7/70625 Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness
• CPC Class Codes: H01J 2237/2817 Pattern inspection
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence

Abstract

A measurement method and system are presented for measuring parameters of a patterned structure. Scatterometry and SEM measurements are applied to the structure, measured data indicative of, respectively, the structure parameters and lateral pattern dimensions of the structure are generated. The entire measured data are analyzed so as to enable using measurement results of either one of the scatterometry and SEM measurements for optimizing the other measurement results.

Claims

1. A method of measuring parameters of a patterned structure, the method comprising

operating a handling system, operable for moving the patterned structure between first and second measurement zone, to locate the structure in a first measurement zone and support the structure during measurements, applying scatterometry measurements to the structure while in the first measurement zone, and generating first measured data presenting first measurement results indicative of at least one predetermined parameter of the structure;

operating sail handling system to locate the structure in a second measurement zone and support the structure during measurements, applying scanning electron microscopy (SEM) measurements to the structure in second measurement zone, and generating second measured data presenting second measurement results indicative of critical dimensions of the structure;

analyzing the first and second measured data to use either one of said first and second measurement results for optimizing the other measurement results.

2. The method according to claim 1, comprising calibrating between the first measured data and the second measured data, and generating calibration results, which are used for the optimization of at least one of said first and second measurement results.

3. The method according to claim 2, wherein said calibrating comprises:

applying both the scatterometry and the SEM measurements to a test structure, which is similar to said structure under measurements and has a set of different pattern profiles, thereby producing the first and second measured data, respectively, for each of said pattern profiles;

analyzing the first measured data to reconstruct the profiles and classify said profiles according to at least one profile parameter;

correlating the second measurement results indicative of the critical dimensions of said test structure as obtained from the first and second measured data for each of the profile classes, and establishing an offset value between the first and second measurement results for each profile class of the test structure; and

using the offset value for a specific profile class to correct, the SEM measurement result for said specific profile class identified by the scatterometry measurement.

4. The method according to claim 1, wherein the scatterometry measurement results are obtained by analyzing the scatterometry measured data using fitting between said second measured data and corresponding data obtained with a theoretical model of the scatterometry measurements, the optimization of the scatterometry measurement results comprising selection the critical dimensions'"'"' parameter as obtained with the SEM measurements to be used in the fitting procedure.

5. The method according to claim 1, wherein the optimization of the SEM measurement results comprises analyzing the SEM measured data to obtain data indicative of structure parameters other than the critical dimensions of the pattern.

6. The method according to claim 5, wherein said analyzing of the SEM measured data comprises using of a learning mode trained with both the scatterometry measurement results and the SEM measured data.

7. The method according to claim 6, wherein the learn mode training comprises:

applying both the scatterometry and the SEM measurements to a test structure, which is similar to said structure under measurements and has a set of different pattern profiles, thereby producing the first and second measured data, respectively;

analyzing the first measured data to classify the profile patterns of the test structure into several groups, to thereby provide a map of the scatterometry profile results per said groups of the pattern profiles,

carrying out said learn mode training of an expert system to be responsive to the second measured data to determine the corresponding group of the profile patterns.

8. The method according to claim 7, wherein said profile patterns are classified in accordance with different shapes of the profile.

9. The method according to claim 8, wherein the profile shape includes at least one of the following:

trapezoidal, re-entrant, rounded-top shapes.

10. The method according to claim 6, wherein the learn mode training comprises:

applying both the scatterometry and the SEM measurements to a test structure, having similar layers as in said structure under measurements and a set of different pattern profiles, thereby producing the first and second measured data, respectively;

analyzing the first measured data to determine values of the profile parameters,

carrying out said learn mode training of at least one expert system to be responsive to the second measured data to determine the corresponding values of the profile parameters.

11. The method according to claim 6, wherein the learn mode training comprises:

applying both the scatterometry and the SEM measurements to a test structure, having similar layers as in said structure under measurements and a set of different pattern profiles, thereby producing the first and second measured data, respectively;

analyzing the first measured data to classify the profile patterns into several groups, to thereby provide a map of the scatterometry profile results per said groups of the pattern profiles,

analyzing the second data so as to determine an offset between the first and second measured data for each of said groups;

carrying out said learn mode training of an expert system to be responsive to data indicative of an offset between the first and second measured data to determine the corresponding group of the profile patterns.

12. The method according to claim 1, for measuring in a semiconductor wafer, and also comprising correlating the measurement results obtained by measuring in a die and a scribe-line of a wafer, wherein measurements in the die include the SEM measurements, while the measurements in the scribe line includes the scatterometry and the SEM measurements.

13. The method according to claim 1, wherein the scatterometry measurements are applied to the structure while progressing on a production line, thereby enabling integrated process control.

14. A measurement system for measuring parameters of a patterned structure, the system comprising:

(a) a scatterometry measurement tool operable to apply measurements to the structure when located in a first measurement zone, and generate first measured data presenting first measurement results indicative of at least one predetermined parameter of the structure characterizing a file of the pattern;

(b) a scanning electron microscope (SEM) measurement tool operable to apply SEM measurements to the structure when located in a second measurement zone, and generate second measured data presenting second measurement results indicative of critical dimensions of the patterned structure;

(c) a handling system operable for moving the structure between the first and second measurement zones and supporting the structure during measurements;

(d) a control system for selectively operating the scatterometry measurement tools and the SEM measurement tool to apply respective measurements to the structure, the control system having a data processing and analyzing utility preprogrammed to be responsive to the first and second measured data and analyzing said data by using either one of first and second measurement results for optimizing the other of the first and second measurement results of the other tool.

15. The system according to claim 14, wherein said SEM measurement tool has a vacuum chamber, in which the structure under measurements is located, said scatterometry measurement tool being located outside said chamber for applying scatterometry measurements to the structure through an optical window made in the chamber.

16. The system according to claim 14, wherein at least an optical arrangement of the scatterometry measurement tool for directing radiation to and from the structure is located inside a vacuum chamber of the SEM measurement tool.

17. A method of measuring parameters of a patterned structure, the method comprising:

(a) applying scatterometry measurements to the structure while located in a first measurement zone, and generating first measured data presenting first measurement results indicative of at least one predetermined parameter of the structure;

(b) applying scanning electron microscopy (SEM) measurements to the structure while located in a second measurement zone, and generating second measured data presenting second measurement results indicative of critical dimensions of the structure;

(c) analyzing the first and second measured data to use said first measurement results for optimizing the q second measurement results.

18. The method according to claim 17, wherein the analyzing of the SEM measured data comprises using a learning mode trained with both the scatterometry and SEM measured data.

19. The method according to claim 18, wherein the learn mode training comprises:

applying both the scatterometry and the SEM measurements to a test structure, which is similar to said structure under measurements and has a set of different pattern profiles, thereby producing the first and second measured data, respectively;

analyzing the first measured data to classify the profile patterns of the test structure into several groups, to thereby provide a map of the scatterometry profile results per said groups of the pattern profiles,

carrying out said learning mode training of an expert system to be responsive to the second measured data to determine the corresponding group of the profile patterns.

20. The method according to claim 19, wherein said profile patterns are classified in accordance with different shapes of the profile.

21. The method according to claim 20, wherein the profile shape includes at least one of the following:

trapezoidal, re-entrant, rounded-top shapes.

22. The method according to claim 18, wherein the learn mode training comprises:

applying both the scatterometry and the SEM measurements to a test structure, having similar layers as in said structure under measurements and a set of different pattern profiles, thereby producing the first and second measured data, respectively;

analyzing the first measured data to determine values of the profile parameters,

carrying out said learn mode training of at least one expert system to be responsive to the second measured data to determine the corresponding values of the profile parameters.

23. The method according to claim 18, wherein the learn mode training comprises:

applying both the scatterometry and the SEM measurements to a test structure, having similar layers as in said structure under measurements and a set of different pattern profiles, thereby producing the first and second measured data, respectively;

analyzing the first measured data to classify the profile patterns into several groups, to thereby provide a map of the scatterometry profile results per said groups of the pattern profiles,

analyzing the second data so as to determine an offset between the first and second measured data for each of said groups;

carrying out said learn mode training of an expert system to be responsive to data indicative of an offset between the first and second measured data to determine the corresponding group of the profile patterns.

24. A method of measuring parameters of a patterned structure, the method comprising:

(a) applying scatterometry measurements to the structure while located in a first measurement zone, and generating first measured data presenting first measurement results indicative of at least one predetermined parameter of the structure;

(b) applying scanning electron microscopy (SEM) measurements to the structure while located in a second measurement zone, and generating second measured data presenting second measurement results indicative of critical dimensions of the structure;

(c) analyzing the first and second measured data to use said first measurement results for optimizing the second measurement results to include data indicative of structure parameters other than the critical dimensions of the pattern.