Method of correcting defects in a reflection-type mask and mask-defect correction apparatus
View Patent ↗According to one embodiment, a method of correcting defects in a reflection-type mask is provided, which comprises acquiring a mask-pattern image of the mask, by using a mask-defect correction apparatus includes a mechanism configured to detect a defect in the mask and a mechanism configured to correct the defect, acquiring a simulated wafer-transfer optical image for the mask, by using an AIMS configured to simulate a wafer-transfer optical image, thereby to determine whether the mask is defective, locating a mask defect, in a mask-pattern image acquired by the mask-defect correction apparatus, by referring to the simulated pattern image acquired by the AIMS, and correcting the defect by the mask-defect correction apparatus, on the basis of the position of the mask defect, thus detected.
1. A method of correcting defects in a reflection mask, comprising:
providing a mask-defect correction apparatus comprising a mechanism configured to detect a defect in the mask and a mechanism configured to correct the defect, and an Aerial Imaging Measurement System (AIMS) configured to simulate a wafer-transfer optical image, thereby to determine whether the mask is defective;
using the AIMS to detect a phase defect in a blank of the mask;
forming, near the defect detected, a marker capable of being detected by the mask-defect correction apparatus;
detecting the marker by the mask-defect correction apparatus, and correcting the defect with reference to the position of the marker; and
removing the marker from the mask in which the defect has been corrected.
2. The method according to claim 1 , wherein forming a marker is to deposit a material whose principal component is carbon locally on the mask.
3. The method according to claim 1 , wherein forming a marker is to etch a part of a pattern formed on the mask.
4. The method according to claim 3 , wherein removing the marker is to deposit shield material at the part of the pattern, which has been etched.
5. The method according to claim 1 , wherein correcting the defect is to measure a distance from the marker to the defect by the AIMS, and to correct the defect by the mask-defect correction apparatus on the assumption that the defect exists at the distance measured.
6. The method according to claim 1 , wherein the mask has been produced by forming a multi-layer reflection film and forming an absorber pattern on the multi-layer reflection film.
7. The method according to claim 6 , wherein the defect is a phase defect existing in the multi-layer reflection film.
8. The method according to claim 1 , wherein the mask-defect correction apparatus comprises a mechanism configured to apply gas or an electron beam, thereby to deposit or remove an absorber locally, and a mechanism configured to acquire a SEM image by means of electron beam scanning.