Method of reviewing detected defects

• US 20030058435A1
• Filed: 08/19/2002
• Published: 03/27/2003
• Est. Priority Date: 09/26/2001
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Okuda, Hirohito, Honda, Toshifumi, Takagi, Yuji
• Granted Patent: US 6,965,429 B2
• Time in Patent Office: Days
• US Class Current: 356/237.1
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G01N 21/956 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 H01L22/10

Abstract

A method to solve the problem of a technique generally used to detect a defect of a semiconductor by calculating the differential image based on pattern matching, which requires that a reference image must be picked up to pick up an image of the inspection position in an area with the semiconductor pattern having no periodicity, resulting in a low throughput. The image of the inspection position is divided into local areas, each local area is matched with the local area of the image already stored and the difference between the local areas thus matched is determined to extract a defect area.

Claims

1. A method for reviewing the defect inspection, comprising:

the defect image pick-up step for moving the field of view of a microscope to the position of inspecting a sample and picking up an image of the external appearance of said inspection position;

the reference image pick-up determination step for determining whether the image of the external appearance of a reference position designed to have the same external appearance as said inspection position is to be picked up or not;

the reference image pick-up step for moving said field of view of the microscope to said reference position and picking up an image of the external appearance of said reference position in accordance with the result of determination in said reference image pick-up determination step;

the defect area extraction step for extracting a defect area at said inspection position from at least selected one of only the image of the external appearance of said inspection position and both the image of the external appearance of said inspection position and the image of the external appearance of said reference position in accordance with the result of determination in said reference image pick-up determination step; and

the defect area post-extraction step for executing a process based on the result of said defect area extraction;

wherein said reference image pick-up determination step includes at least selected one of the image pick-up pre-start reference image pick-up determination step for provisionally determining, before said defect image pick-up step, whether the image of the external appearance of said reference position is to be picked up or not and the image pick-up post-start reference image pick-up determination step for finally determining, after said defect image pick-up step, whether the image of the external appearance of said reference position is to be picked up or not; and

wherein selected one of said defect image pick-up step and said reference image pick-up step is executed concurrently with said image pick-up post-start reference image pick-up determination step for an inspection position different from said inspection position determined in said image pick-up post-start reference image pick-up determination step.

2. A method of reviewing the defect inspection according to claim 1,

wherein said defect area post-extraction step includes

the enlarged defect image pick-up step for picking up an image of said external appearance of the area determined as a defect in said defect extraction step with a magnification larger than in said defect image pick-up step,

the enlarged reference image pick-up determination step for determining whether an enlarged reference image of an area having the same external appearance as the area with the image thereof picked up in said enlarged defect image pick-up step is to be picked up with the same magnification as in said enlarged defect image pick-up step, and

the enlarged reference image pick-up step for picking up said enlarged reference image based on the result of determination in said enlarged reference image pick-up determination step;

wherein said enlarged reference image pick-up determination step includes at least selected one of

the image pick-up pre-start enlarged reference image pick-up determination step for provisionally determining, before said enlarged defect image pick-up step, whether said enlarged reference image is to be picked up or not, and

the image pick-up post-start enlarged reference image pick-up determination step for finally determining, after said enlarged defect image pick-up step, whether said enlarged reference image is to be picked up or not; and

wherein selected one of said defect image pick-up step, said reference image pick-up step, said enlarged defect image pick-up step and said enlarged reference image pick-up step is executed concurrently with selected one of said image pick-up post-start reference image pick-up determination step and said image pick-up post-start enlarged reference image pickup determination step for an inspection position different from the inspection position determined in selected one of said image pick-up post-start reference image pick-up determination step and said image pick-up post-start enlarged reference image pick-up determination step.

3. A method of reviewing the defect inspection according to claim 1,

wherein the image pick-up means in said defect image pick-up step and said reference image pick-up step is an electron microscope,

wherein an image is obtained by scanning electrons at least once in the image pick-up field of view at each of an inspection position and a reference position,

wherein both a defect search image picked up by scanning an image the same number of times as in said reference image pick-up step and a defect review image picked up by scanning more electrons than in said reference image pick-up step are produced in said defect image pick-up step, and

wherein a defect is extracted in said reference image pick-up determination step by comparing the defect search image picked up in said defect image pick-up step with the image picked up in said reference image pick-up step.

4. A method of reviewing the defect inspection according to claim 1,

wherein said defect extraction step includes

the reference image generating step for generating said reference image based on the image of the external appearance of said inspection position and the inspection data registered for extracting a defect area from said inspection position, in the case where it is determined in said reference image pick-up determination step that said reference image is not picked up, and

the defect area calculation step for extracting a defect area by comparing the image of the external appearance of said inspection position with selected one of the image of the external appearance of said reference position and said reference image synthesized in said reference image generating step.

5. A method of reviewing the defect inspection according to claim 1,

wherein said defect extraction step includes

the statistical amount map calculation step for calculating the statistical amount indicating the existence probability for selected one of each of the local areas and the pixels of the image of the external appearance of said inspection position based on the image of the external appearance of said inspection position and the inspection data registered for extracting a defect area from said inspection position in the case where it is determined in said reference image pick-up determination step that said reference image is not picked up, and

the defect area calculation step for extracting a defect area by comparing the image of the external appearance of said inspection position with selected one of the image of the external appearance of said reference position and said statistical amount calculated in said statistical amount map calculation step.

6. A method of reviewing the defect inspection according to claim 4,

wherein a reference image is constituted of an already stored image including said reference image picked up for extracting a defect of an object different from said inspection position, and

wherein said inspection data includes at least selected one of the inspection method for the inspection system used for inspecting said inspection position before said method of reviewing the defect inspection, the design data of said inspection position and said reference data.

7. A method of reviewing the defect inspection according to claim 4,

wherein said reference image is generated in said reference image generating step in such a manner that a local area of the image of the external appearance of said inspection position is used as a local area for defect extraction, an area in the neighborhood of said defect extraction local area is used as a local matching area for defect extraction, and based on at least selected one of the image of the external appearance of said inspection position corresponding to said extraction matching area and the design data of said inspection position, an area determined to have the same pattern as said extraction matching area is set as a reference local area constituting an area corresponding to said defect extraction local area from selected one of the image of the external appearance of said inspection position and said reference image thereby to generate said reference image.

8. A method of reviewing the defect inspection according to claim 5,

wherein said statistical amount map is calculated in said statistical amount map calculation step in such a manner a local area of the image of the external appearance of said inspection position is used as a local area for defect extraction, an area in the neighborhood of said defect extraction local area is used as a local matching area for defect extraction, and based on at least selected one of the image of the external appearance of said inspection position corresponding to said extraction matching area and the design data of said inspection position, a plurality of areas determined to have the same pattern as said extraction matching area are set as a plurality of reference local areas corresponding to said defect extraction local area from selected one of the image of the external appearance of said inspection position and said reference image.

9. A method of reviewing the defect inspection according to claim 1,

wherein the determination is made based on at least selected one of the inspection method for the inspection system used for inspection of said inspection position before said defect inspection review method, the design data of said inspection position and said reference image picked up to extract a defect of an object different from said inspection position.

10. A method of reviewing the defect inspection according to claim 4,

wherein said defect inspection review method makes it possible to display a reference image generated in said reference image generating step as an image to the user, and makes it possible for the user to confirm the generation of said reference image.

11. A method of reviewing the defect inspection according to claim 7,

wherein said reference local area is set in said reference image generating step in such a manner that said defect extraction local area is subjected to subband decomposition, and each subband component is obtained by subband decomposition of selected one of the image of the external appearance of said inspection position and said reference image.

12. A method of reviewing the defect inspection, comprising:

the defect image pick-up step for moving the field of view of a microscope to a sample inspection position and picking up an image of the external appearance of said inspection position by scanning a focused electron beam;

the reference image pick-up step for moving said field of view of said microscope to a reference position and picking up an image of the external appearance of said reference position by scanning said focused electron beam;

the defect area extraction step for extracting a defect area of said inspection position using said image of the external appearance of said inspection position and said image of the external appearance of said reference position; and

the defect image display step for displaying on a screen the image of a defect area extracted in said defect area extraction step;

wherein said image of the external appearance of said reference position is picked up in such a manner that the number of times said electron beam is scanned at said reference position in said reference image pick-up step is smaller than the number of times said electron beam is scanned in said defect image pick-up step.

13. A method of reviewing the defect inspection according to claim 12,

wherein said image of the defect position to be displayed has the same magnification as the image of the external appearance picked up in said defect image pick-up step.

14. A method of reviewing the defect inspection, comprising:

the defect image pick-up step for moving the field of view of a microscope to a sample inspection position and picking up an image of the external appearance of said inspection position by scanning a focused electron beam;

the reference image pick-up step for moving said field of view of said microscope to a reference position and picking up an image of the external appearance of said reference position by scanning said focused electron beam;

the defect area extraction step for extracting a defect area of said inspection position using said image of the external appearance of said inspection position and said image of the external appearance of said reference position; and

the defect image display step for displaying on a screen the image of the defect area extracted in said defect area extraction step;

wherein the image of the external appearance picked up in said defect image pick-up step is compared with the image of the external appearance picked up in said reference image pick-up step thereby to detect a defect position, and an image of said detected defect position is displayed by being extracted from the image of the external appearance picked up in said defect image pick-up step.

15. A method of reviewing the defect inspection according to claim 14,

wherein the image of said defect position to be displayed has the same magnification as the image of the external appearance picked up in said defect image pick-up step.