Method of removing defect of mask
A method of removing a defect of a mask may include generating a probe profile, the probe profile including characteristics of a probe of an atomic force microscope (AFM); generating a design-based reference image of a defect area by applying the probe profile to a design image of the defect area of the mask including a location of the defect; obtaining an AFM image of the defect area by scanning the defect area of the mask using the probe of the AFM; recognizing the defect as a recognized defect by comparing the AFM image of the defect area with the design-based reference image; and removing the recognized defect using the probe of the AFM.
1 . A method of removing a defect of a mask, the method comprising:
generating a probe profile, the probe profile including characteristics of a probe of an atomic force microscope (AFM);
generating a design-based reference image of a defect area by applying the probe profile to a design image of the defect area of the mask including a location of the defect;
obtaining an AFM image of the defect area by scanning the defect area of the mask using the probe of the AFM;
recognizing the defect as a recognized defect by comparing the AFM image of the defect area with the design-based reference image; and
removing the recognized defect using the probe of the AFM.
2 . The method of claim 1 , further comprising:
calibrating an offset of the probe of the AFM by scanning an offset calibration region included in the mask using the probe of the AFM.
3 . The method of claim 2 , wherein
in the calibrating the offset of the probe of the AFM, the AFM image of the offset calibration region is obtained by scanning the offset calibration region using the probe of the AFM, and
the probe profile is generated by comparing the AFM image of the offset calibration region obtained in the calibrating the offset of the probe of the AFM with a design image of the offset calibration region.
4 . The method of claim 3 , wherein
the design image of the defect area of the mask and the design image of the offset calibration region each are extracted from a mask layout in a graphic database II (GDSII) stream format.
5 . The method of claim 1 ,
wherein the characteristics of the probe included in the probe profile include a 3D image of the probe of the AFM, an aspect ratio of the probe of the AFM, a degree of wear of the probe of the AFM, and an asymmetry of the probe of the AFM.
6 . The method of claim 1 , wherein
after obtaining the AFM image of the defect area, the recognized defect is removed using the probe of the AFM without moving the probe of the AFM to another area.
7 . The method of claim 1 , wherein
in the recognizing the defect as the recognized defect, only one AFM image of the defect area obtained by scanning the defect area of the mask using the probe of the AFM is compared with the design-based reference image.
8 . The method of claim 1 , wherein
the location of the defect is extracted from the location of the defect of a semiconductor wafer obtained through defect inspection of the semiconductor wafer where patterns are formed using the mask or the location of the defect is extracted from a location of a defect of the semiconductor wafer obtained through an electrical test for the semiconductor wafer where patterns are formed using the mask.
9 . The method of claim 1 , wherein
the design-based reference image of the defect area is generated by a convolution of a design image of the defect area of the mask and the probe profile.
10 . The method of claim 1 , wherein
during the removing the recognized defect using the probe of the AFM, the probe applies physical force to the recognized defect to remove the recognized defect.
11 . The method of claim 1 , wherein
the mask comprises a substrate having a main exposure area and an offset calibration region, patterns on the substrate in the main exposure area, and a dummy pattern on the substrate in the offset calibration region,
the defect area of the mask is positioned within the main exposure area,
the offset calibration region of the mask includes a portion of an edge of the dummy pattern extending in a first horizontal direction and a portion of an edge of the dummy pattern extending in a second horizontal direction, and
the second horizontal direction is orthogonal to the first horizontal direction.
12 . A method of removing a defect of a mask, the method comprising:
scanning an offset calibration region included in a mask using a probe of an atomic force microscope (AFM) to obtain an AFM image of the offset calibration region and calibrating an offset of the probe of the AFM by adjusting a zero point;
generating a probe profile by comparing the AFM image of the offset calibration region with a design image of the offset calibration region, the probe profile including characteristics of the probe of the AFM;
generating a design-based reference image of a defect area by applying the probe profile to a design image of the defect area of the mask including a location of the defect;
obtaining an AFM image of the defect area by scanning the defect area of the mask using the probe of the AFM;
recognizing the defect as a recognized defect by comparing the AFM image of the defect area with the design-based reference image; and
removing the recognized defect using the probe of the AFM.
13 . The method of claim 12 , wherein
the characteristics of the probe included in the probe profile include information on an aspect ratio of the probe of the AFM, a degree of wear of the probe of the AFM, and an asymmetry of the probe of the AFM corresponding to a three-dimensional image of the probe.
14 . The method of claim 13 , wherein
the mask includes a substrate having a main exposure area and the offset calibration region, patterns on the substrate in the main exposure area, and a dummy pattern on the substrate in the offset calibration region,
the defect area is located on the main exposure area,
the offset calibration region of the mask includes a corner portion of the dummy pattern where a portion of an edge extending in a first horizontal direction intersects with a portion of an edge extending in a second horizontal direction, and
the second horizontal direction is orthogonal to the first horizontal direction.
15 . The method of claim 14 , wherein
in the AFM image of the offset calibration region, the degree of wear of the probe of the AFM is obtained by comparing a degree of blurring occurring at the portion of the edge of the dummy pattern extending in the first horizontal direction with a degree of blurring occurring at the portion of the edge of the dummy pattern extending in the second horizontal direction.
16 . The method of claim 12 , wherein
in the recognizing the defect as the recognized defect, only one AFM image of the defect area obtained by scanning the defect area of the mask using the probe of the AFM is compared with the design-based reference image.
17 . The method of claim 16 , wherein
after obtaining the AFM image of the defect area, the recognized defect is removed by applying physical force to the recognized defect using the probe of the AFM without moving the probe of the AFM to another area.
18 . The method of claim 12 ,
wherein the design-based reference image of the defect area is generated by a convolution of the probe profile and the design image of the defect area of the mask.
19 . A method of removing a defect of a mask, the method comprising:
preparing a mask including a substrate having a main exposure area and an offset calibration region, patterns on the substrate in the main exposure area, and a dummy pattern on the substrate in the offset calibration region;
obtaining an atomic force microscope (AFM) image of the offset calibration region by scanning the offset calibration region of the mask using a probe of an AFM, and calibrating the offset of the probe of the AFM by adjusting a zero point;
generating a probe profile by comparing the AFM image of the offset calibration region with a design image of the offset calibration region, the probe profile including characteristics of a probe of the AFM;
generating a design-based reference image of a defect area by a convolution of a design image of the defect area of the mask including a location of the defect and the probe profile;
obtaining an AFM image of the defect area by scanning the defect area of the mask using the probe of the AFM;
recognizing the defect as a recognized defect by comparing the AFM image of the defect area with the design-based reference image;
removing the recognized defect using the probe of the AFM; and
performing a cleaning process on the mask.
20 . The method of claim 19 , wherein
in the recognizing the defect, only one AFM image of the defect area obtained by scanning the defect area of the mask using the probe of the AFM is compared with the design-based reference image,
after the obtaining the AFM image of the defect area, the recognized defect is removed using the probe of the AFM without moving the probe of the AFM to another area.