Methods and systems for detecting defects in a reticle design pattern

• US 8,213,704 B2
• Filed: 05/07/2008
• Issued: 07/03/2012
• Est. Priority Date: 05/09/2007
• Status: Active Grant

• Current Assignee: KLA-Tencor Corporation
• Original Assignee: KLA-Tencor Corporation
• Inventors: Peterson, Ingrid B., Yum, Ed
• Primary Examiner(s): PHAM, HOA Q
• Application Number:
  US12/116,664
• Publication Number:
  US 20090016595A1
• Time in Patent Office: 1,518 Days
• Field of Search: 382/145, 382/144, 382/146, 382/147, 382/148, 382/149, 382/170, 382/172, 3562371-2375
• US Class Current: 382/145
• 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
• CPC Class Codes: G03F 7/7085 Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load

Abstract

Computer-implemented methods and systems for detecting defects in a reticle design pattern are provided. One computer-implemented method includes acquiring images of the reticle design pattern using a sensor disposed on a substrate arranged proximate to an image plane of an exposure system configured to perform a wafer printing process using the reticle design pattern. The images illustrate how the reticle design pattern will be projected on a wafer by the exposure system at different values of one or more parameters of the wafer printing process. The method also includes detecting defects in the reticle design pattern based on a comparison of two or more of the images corresponding to two or more of the different values.

Claims

1. A computer-implemented method for detecting defects in a reticle design pattern, comprising:

acquiring images of the reticle design pattern using a sensor disposed on a substrate arranged proximate to an image plane of an exposure system configured to perform a wafer printing process using the reticle design pattern, wherein the images illustrate how the reticle design pattern will be projected on a wafer by the exposure system at different values of one or more parameters of the wafer printing process, wherein said acquiring comprises acquiring the images using two or more sensors disposed on the substrate and monochromatic light of the exposure system, wherein the two or more sensors are arranged at different heights on the substrate corresponding to different illumination focus conditions of the exposure system, and wherein the two or more sensors and the substrate are not tilted with respect to the image plane; and

detecting defects in the reticle design pattern based on a comparison of two or more of the images corresponding to two or more of the different values.

2. The method of claim 1, wherein the reticle design pattern comprises the reticle design pattern printed on a reticle.

3. The method of claim 1, wherein said acquiring further comprises acquiring the images in situ.

4. The method of claim 1, wherein the one or more parameters comprise illumination focus, exposure, degree of partial coherence, illumination mode, numerical aperture, or some combination thereof.

5. The method of claim 1, wherein the different values of the one or more parameters of the wafer printing process comprise different values in a focus and exposure matrix.

6. The method of claim 1, wherein the different values of the one or more parameters of the wafer printing process comprise different values across a predetermined process window for the reticle design pattern.

7. The method of claim 1, further comprising determining a process window for the wafer printing process to be performed using the reticle design pattern.

8. The method of claim 1, wherein said acquiring further comprises acquiring two or more of the images at two or more of the different values using the two or more sensors disposed on the substrate without altering one or more parameters of the exposure system between acquisition of the two or more of the images.

9. The method of claim 1, wherein the exposure system comprises an optical exposure system.

10. The method of claim 1, wherein the exposure system comprises an electron beam exposure system.

11. The method of claim 1, wherein the exposure system comprises a direct write exposure system.

12. The method of claim 1, wherein the sensor comprises a scintillator.

13. A computer-implemented method for detecting defects in a design pattern, comprising:

acquiring an image of the design pattern using a sensor disposed on a substrate arranged proximate to an image plane of a direct write exposure system configured to perform a wafer printing process using the design pattern, wherein the image illustrates how the design pattern will be projected on a wafer by the direct write exposure system in the wafer printing process, wherein said acquiring comprises acquiring images using two or more sensors disposed on the substrate and monochromatic light of the direct write exposure system, wherein the two or more sensors are arranged at different heights on the substrate corresponding to different illumination focus conditions of the direct write exposure system, and wherein the two or more sensors and the substrate are not tilted with respect to the image plane; and

detecting defects in the design pattern based on a comparison between the image and a reference.

14. The method of claim 13, wherein the reference is generated using a database for the design pattern.

15. The method of claim 13, wherein the direct write exposure system comprises an electron beam direct write exposure system.

16. The method of claim 13, wherein the sensor comprises a scintillator.

17. A system configured to detect defects in a reticle design pattern, comprising:

two or more sensors configured to acquire images of the reticle design pattern, wherein the two or more sensors are disposed on a substrate arranged proximate to an image plane of an exposure system configured to perform a wafer printing process using the reticle design pattern and monochromatic light, wherein the two or more sensors are arranged at different heights on the substrate corresponding to different illumination focus conditions of the exposure system, wherein the two or more sensors and the substrate are not tilted with respect to the image plane, wherein the images are acquired using the monochromatic light, and wherein the images illustrate how the reticle design pattern will be projected on a wafer by the exposure system at different values of one or more parameters of the wafer printing process; and

a processor coupled to the two or more sensors, wherein the processor is configured to detect defects in the reticle design pattern based on a comparison of two or more of the images corresponding to two or more of the different values.

18. The system of claim 17, wherein the exposure system comprises an optical exposure system.

19. The system of claim 17, wherein the exposure system comprises an electron beam exposure system.

20. The system of claim 17, wherein the exposure system comprises a direct write exposure system.

21. The system of claim 17, wherein the sensor comprises a scintillator.