Method of repairing a mask

Patent metadata

Field	Value
Publication number	US-9400424-B2
Application number	US-201514688141-A
Country	US
Kind code	B2
Filing date	Apr 16, 2015
Priority date	Mar 12, 2013
Publication date	Jul 26, 2016
Grant date	Jul 26, 2016

Abstract

The present disclosure provides a method of repairing a mask. The method includes inspecting the mask using a mask inspection tool to identify a defect on a circuit pattern of the mask; repairing the defect using a mask repair tool to form a repaired pattern; forming a first group of diffraction images of the repaired pattern and a second group of diffraction images of a reference feature; and validating the mask by comparing the first group of diffraction images with the second group of diffraction images.

First claim

What is claimed is:

1. A method, comprising:
receiving a mask including a defect;
repairing the defect, the repairing comprising:
inspecting the mask to locate the defect;
repairing the defect using a mask repair tool to form a repaired feature; and
validating the repaired feature using a diffraction image of the repaired feature,
wherein the diffraction image of the repaired feature is formed using a first point source; and

after repairing the defect, forming a patterned resist layer on a semiconductor wafer by a lithography process using the mask.

2. The method of claim 1 , wherein:
the mask is a reflective mask; and
the forming the patterned resist layer includes exposing a resist layer using an extreme ultraviolet (EUV) lithography system.

3. The method of claim 1 , wherein inspecting the mask includes using a mask inspection tool to identify the defect on a circuit pattern of the mask.

4. The method of claim 1 , further comprising:
forming, using the first point source, a diffraction image of a reference feature, wherein the validating the repaired feature includes comparing the diffraction image of the repaired feature with the diffraction image of the reference feature.

5. The method of claim 4 , wherein:
the diffraction image of the repaired feature includes a first plurality of diffraction order images;
the diffraction image of the reference feature includes a second plurality of diffraction order images; and
the validating the repaired feature includes comparing first intensities and numerical apertures of the first plurality of diffraction order images to second intensities and numerical apertures of the second plurality of diffraction order images, respectively.

6. The method of claim 5 , wherein the first and second plurality of diffraction order images include zero order, first order, and second order diffraction images.

7. The method of claim 5 , wherein the validating the repaired feature includes evaluating differences between the first intensities and numerical apertures of the first plurality of diffraction order images and the second intensities and numerical apertures of the second plurality of diffraction order images, respectively according to predefined criteria.

8. The method of claim 1 , further comprising:
forming a first group of diffraction images of the repaired feature and a second group of diffraction images of the reference feature, wherein the forming the first and second group of diffraction images includes:
forming first two diffraction images of the repaired feature using the first point source and a second point source, respectively; and
forming second two diffraction images of the reference feature using the first point source and the second point source, respectively.

9. The method of claim 8 , wherein the first and second point sources are a pair of symmetric point sources.

10. The method of claim 4 , wherein the reference feature is a defect-free pattern on the mask.

11. The method of claim 3 , wherein:
the circuit pattern includes a first feature where the defect is located;
a reference feature includes a second feature; and
the first feature and the second feature have a same dimension by design.

12. A method of pattern formation, comprising:
receiving a mask having a first feature with a defect and a second feature;
inspecting the mask using a mask inspection tool to locate the defect;
repairing the defect using a mask repair tool, resulting in the mask having a repaired first feature;
forming a first diffraction image of the repaired first feature using a first point source;
forming a second diffraction image of the second feature using the first point source;
validating the repaired first feature by comparing the first diffraction image with the second diffraction image; and
forming a patterned resist layer on a semiconductor wafer by a lithography process using the mask including the repaired first feature.

13. The method of claim 12 , wherein
the first diffraction image includes a first plurality of diffraction order images;
the second diffraction image includes a second plurality of diffraction order images; and
the validating the repaired first feature includes comparing first intensities and numerical apertures of the first plurality of diffraction order images to second intensities and numerical apertures of the second plurality of diffraction order images, respectively.

14. The method of claim 13 , wherein the validating the repaired first feature includes evaluating differences between the first intensities and numerical apertures of the first plurality of diffraction order images and the second intensities and numerical apertures of the second plurality of diffraction order images, respectively according to predefined criteria, and wherein the repaired first feature is validated if the differences are within the predefined criteria.

15. The method of claim 12 , further comprising:
forming a third diffraction image of the repaired first feature using a second point source; and
forming a fourth diffraction image of the second feature using the second point source,
wherein the validating the repaired first feature further includes comparing the third diffraction image to the fourth diffraction image.

16. The method of claim 12 , further comprising at least one of performing an implant process into the semiconductor wafer using the patterned resist layer as a mask and performing an etching process to transfer a pattern of the patterned resist layer to the semiconductor wafer.

17. A method, comprising:
receiving a mask including a defect;
scanning the mask to locate the defect;
repairing the defect using a mask repair tool to form a repaired circuit pattern on the mask;
validating the repaired circuit pattern by comparing a diffraction image of the repaired circuit pattern to a diffraction image of a reference pattern;
depositing a resist layer on a semiconductor wafer; and
using the mask including the repaired circuit pattern, forming a patterned resist layer on the semiconductor wafer by a lithography process.

18. The method of claim 17 , wherein validating the repaired circuit pattern further includes:
determining that a difference between the compared diffraction images of the repaired circuit pattern and the reference pattern are out of a specification limit; and
based on the determining, reworking the mask until the defect is repaired.

19. The method of claim 17 , wherein the mask includes a mask selected from the group consisting of a binary mask, a phase shift mask, and a reflective mask.

20. The method of claim 17 , further comprising:
prior to forming the patterned resist layer on the semiconductor wafer, forming at least one of a bottom antireflective coating (BARC) layer and a top antireflective coating (TARC) layer.

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Chu Fu-Sheng
• Chu Yuan-Chih

Classifications

• G01N21/95607

  using a comparative method · CPC title

• G03F1/84

  Inspecting · CPC title

• G01N21/956

  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 H10P74/20)} · CPC title

• G03F1/72 Primary

  Repair or correction of mask defects · CPC title

• G03F7/2002

  with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image · CPC title