Qualifying patterns, patterning processes, or patterning apparatus in the fabrication of microlithographic patterns

• US 7,418,124 B2
• Filed: 07/15/2003
• Issued: 08/26/2008
• Est. Priority Date: 07/15/2002
• Status: Active Grant

• Current Assignee: Kla-Tencor Technologies Corporation (KLA Corporation)
• Original Assignee: Kla-Tencor Technologies Corporation (KLA Corporation)
• Inventors: Peterson, Ingrid B., Von den Hoff, Mike, Wiley, Jim
• Primary Examiner(s): Mehta; Bhavesh
• Assistant Examiner(s): DULANEY, KATHLEEN YUAN
• Application Number:
  US10/619,943
• Publication Number:
  US 20040091142A1
• Time in Patent Office: 1,869 Days
• Field of Search: 382/141, 382/145, 382/144, 348/131, 359/385, 703/13
• US Class Current: 382/144
• CPC Class Codes: G03F 1/84 Inspecting
• CPC Class Codes: G03F 7/7065 Defects, e.g. optical inspection of patterned layer for defects
• CPC Class Codes: G03F 7/70666 Aerial image, i.e. measuring the image of the patterned exposure light at the image plane of the projection system

Abstract

Methods that include acquiring aerial images of a reticle for different values of a member of a set of lithographic variables are provided. One method also includes determining a presence of an anomaly in a design pattern of the reticle by comparing at least one pair of the aerial images corresponding to at least two of the different values. A different method includes comparing at least one pair of the aerial images corresponding to at least two of the different values and determining an area on the reticle where a lithography process using the reticle is most susceptible to failure based on the results of the comparison. Another embodiment includes determining a presence of transient repeating defects on the reticle by subtracting non-transient defects from the aerial images and comparing at least one pair of the aerial images corresponding to at least two of the different values.

Claims

1. A method, comprising:

acquiring aerial images of a reticle containing a design pattern, wherein the aerial images are acquired for different values of a member of a set of lithographic variables, and wherein one of the different values represents a reference member value;

inspecting the reticle for non-transient defects; and

determining a presence of transient repeating defects on the reticle by subtracting non-transient defects from the aerial images and comparing at least one pair of the aerial images corresponding to at least two of the different values, wherein one of the at least two of the different values represents the reference member value, and wherein the transient repeating defects are defects that will print under only a portion of the different values.

2. The method of claim 1, wherein the member comprises illumination focus, exposure, degree of partial coherence, illumination mode, or numerical aperture.

3. The method of claim 1, wherein the reticle is a single die reticle or a multi-die reticle.

4. The method of claim 1, wherein the aerial images are acquired with different detectors having the different values.

5. The method of claim 1, wherein said inspecting the reticle is performed using one of the aerial images, and wherein the non-transient defects comprise reticle manufacturing errors and contaminants.

6. The method of claim 1, wherein said inspecting comprises a die-to-database comparison or a die-to-die comparison.

7. The method of claim 1, further comprising prior to said determining, preprocessing the at least one pair of the aerial images to remove relatively high intensity values and relatively low intensity values from the at least one pair of the aerial images.

8. The method of claim 1, further comprising identifying regions of the reticle for review based on locations of the transient repeating defects.

9. The method of claim 8, wherein the review comprises aerial image review at varying levels of optical conditions.

10. The method of claim 1, wherein if more than one transient repeating defect is found on the reticle, the method further comprises binning the more than one transient repeating defect according to regions of the reticle proximate the more than one transient repeating defect.

11. The method of claim 1, further comprising determining a process window for a lithography process to be carried out using the reticle.

12. The method of claim 1, further comprising determining a critical status of the transient repeating defects.

13. The method of claim 1, wherein if more than one transient repeating defect is found on the reticle, the method further comprises binning the more than one transient repeating defect by appearance of regions of the reticle immediately surrounding the transient repeating defects.

14. The method of claim 1, wherein if more than one transient repeating defect is found on the reticle, the method further comprises binning the more than one transient repeating defect by patterns surrounding the transient repeating defects.

15. A method, comprising:

acquiring aerial images of a reticle containing a design pattern, wherein the aerial images are acquired for different values of a member of a set of lithographic variables;

inspecting the reticle for non-transient defects;

determining a presence of transient repeating defects on the reticle by subtracting the non-transient defects from the aerial images and comparing at least one pair of the aerial images corresponding to at least two of the different values to find areas on the reticle in which the transient repeating defects on the reticle are located, wherein the transient repeating defects are defects that will print under only a portion of the different values; and

determining which of the areas on the reticle where a lithography process using the reticle is most susceptible to failure based on results of said comparing.

16. The method of claim 15, wherein one of the different values represents a reference member value.

17. The method of claim 16, wherein the area that is most susceptible to failure comprises transient repeating detects that are common to the at least one pair of the aerial images not acquired at the reference member value and that are not common to the aerial image acquired at the reference member value.

18. A method, comprising:

inspecting a reticle containing a design pattern for non-transient defects;

acquiring aerial images of the reticle for different values of a member of a set of lithographic variables; and

determining a presence of transient repeating defects on the reticle by subtracting the non-transient defects from the aerial images and comparing at least one pair of the aerial images corresponding to at least two of the different values, wherein the transient repeating defects are defects that will print under only a portion of the different values.

19. The method of claim 18, wherein said inspecting and said acquiring are performed substantially simultaneously.

20. The method of claim 18, wherein said inspecting comprises aerial imaging of the reticle at a reference member value of the set of the lithographic variables.

21. The method of claim 18, wherein said inspecting is performed using a non-aerial imaging reticle inspection system.

22. The method of claim 18, wherein said inspecting comprises a die-to-database comparison or a die-to-die comparison.

23. The method of claim 18, further comprising determining a process window for a lithography process to be carried out using the reticle based on the transient repeating defects.

24. The method of claim 18, wherein the non-transient defects comprise reticle manufacturing errors or contaminants on the reticle.