Defect and critical dimension analysis systems and methods for a semiconductor lithographic process

1. An inspection apparatus for inspecting patterns formed on a wafer by using an image of said patterns and data for fabricating said patterns, comprising:

an imager for capturing at least one image of each of a plurality of inspection regions on the wafer;

a reference pattern generator for generating a reference pattern for each of the inspection regions from design data of the wafer, the reference pattern being formed of one or both of (a) one or more line segments and (b) one or more curves; and

an inspection unit configured to perform:

detecting edges within each of the images;

automatically selecting patterns within each of the inspection regions based upon tendency for measurement variation resulting from variation in the fabrication process;

comparing, for the selected patterns, certain of the edges with associated line segments and curves of the reference pattern to determine one or both of (a) a maximum empty circle within the boundary of the certain edges and (b) an arbitrarily oriented smallest enclosing rectangle that includes the certain edges; and

generating defect information based upon one or both of the maximum empty circle and the smallest enclosing rectangle.

2. The inspection apparatus of claim 1 , wherein the selected patterns are selected from the group consisting of contact hole, and via.

3. A pattern inspection apparatus for inspecting a pattern by using an image of the pattern and data for fabricating the pattern, the pattern inspection apparatus comprising:

an image generation device configured to generate the image of the pattern;

a processor adapted to execute machine readable instructions; and

a memory storing a plurality of machine readable instructions for execution by the processor that when executed perform the steps of:

detecting edges within the images of the pattern,

storing in the memory a reference pattern generated from the data, the reference pattern represented by one or both of (i) one or more line segments, and (ii) one or more curves, the reference pattern generated from the data;

storing in the memory measured line widths of the image;

inspecting the pattern by using at least one of distances between the detected edges and at least one of the line segments and the curves of the reference pattern to obtain a defect; and

classifying the defect by (i) applying, within the design data and centered on the location of each of the defects, a windowing region to select a windowed pattern associated with the defect; (ii) obtaining a distance between the windowed pattern associated with the defect against each windowed pattern associated with the other defects for each pair of defects; and (iii) grouping defects having distances less than a predefined difference value threshold.

4. The apparatus of claim 3 , wherein the distance between the windowed pattern associated with the defect against each windowed pattern associated with the other defects is obtained from a distance between a vertex of one windowed pattern and a line of the other windowed pattern.

5. A method of evaluating a wafer fabrication process for forming patterns on a wafer based upon design data, comprising:

defining two or more inspection regions on the wafer for analysis;

capturing at least one image in each of the inspection regions on the wafer using an image acquiring device;

storing in a memory a reference pattern generated from the data, the reference pattern represented by one or both of (i) one or more line segments, and (ii) one or more curves, the reference pattern generated from the data;

detecting edges within each of the images;

automatically selecting patterns within each of the inspection regions based upon tendency for measurement variation resulting from variation in the fabrication process;

comparing, for the selected patterns, certain of the edges with associated line segments and curves of the reference pattern to determine one or both of (a) a maximum empty circle within the boundary of the certain edges and (b) an arbitrarily oriented smallest enclosing rectangle that includes the certain edges; and

generating defect information based upon one or both of the maximum empty circle and the smallest enclosing rectangle.

6. The method of claim 5 , wherein the selected patterns are selected from the group consisting of contact hole, and via.

7. A method of evaluating a wafer fabrication process for forming patterns on a wafer based upon design data, comprising:

defining an inspection region on the wafer for analysis;

capturing at least one image in the inspection region on the wafer;

storing in a memory a reference pattern generated from the data, the reference pattern represented by one or both of (i) one or more line segments, and (ii) one or more curves, the reference pattern generated from the data;

detecting edges within each of the images;

storing in the memory measured line widths of the image;

inspecting the pattern by using at least one of distances between the detected edges and at least one of the line segments and the curves of the reference pattern to obtain a defect; and

classifying the defect by (i) applying, within the design data and centered on the location of each of the defects, a windowing region to select a windowed pattern associated with the defect; (ii) obtaining a distance between the windowed pattern associated with the defect against each windowed pattern associated with the other defects for each pair of defects; and (iii) grouping defects having distances less than a predefined difference value threshold.

8. The method of claim 7 , wherein the distance between the windowed pattern associated with the defect against each windowed pattern associated with the other defects is obtained from a distance between a vertex of one windowed pattern and a line of the other windowed pattern.