Apparatus and method for inspecting overlay patterns in semiconductor device

An apparatus for inspecting overlay patterns, comprising:

• an optical module which projects a plurality of neighboring overlay patterns formed on a wafer;
• a pickup unit which obtains a plurality of image signals corresponding to the plurality of overlay patterns projected from the optical module;
• a comparison unit configured to:
• generate a plurality of images including the plurality of overlay patterns from the image signals obtained at the pickup unit;
• compare an overlay pattern image corresponding to any one of the plurality of overlay patterns with a previously input overlay pattern image;
• and
• based on the comparison, extract at least a portion of the overlay pattern image identical or similar to the previously input overlay pattern image;
• a restoration unit which restores the extracted overlay pattern image in accordance with a predetermined overlay pattern;
• and
• a readout unit which calculates and compares a position of the restored overlay pattern image with a position of an overlay pattern image not compared by the comparison unit, and which reads out a deviation between the two positions,
• wherein the comparison unit includes a database which provides at least one pre-stored overlay pattern image, and
• wherein the comparison unit compares a line width of the pre-stored overlay pattern image with a line width of the overlay pattern image corresponding to any one of the plurality of overlay patterns picked up by the pickup unit, and extracts at least a portion of the overlay pattern image from any one of the plurality of overlay patterns where the line widths of the overlay pattern images are equal or similar to each other.

An apparatus for inspecting overlay patterns, comprising:

• an optical module which projects a plurality of neighboring overlay patterns formed on a wafer;
• a pickup unit which obtains a plurality of image signals corresponding to the plurality of overlay patterns projected from the optical module;
• a comparison unit configured to:
• generate a plurality of images including the plurality of overlay patterns from the image signals obtained at the pickup unit;
• compare an overlay pattern image corresponding to any one of the plurality of overlay patterns with a previously input overlay pattern image;
• and
• based on the comparison, extract at least a portion of the overlay pattern image identical or similar to the previously input overlay pattern image;
• a restoration unit which restores the extracted overlay pattern image in accordance with a predetermined overlay pattern;
• and
• a readout unit which calculates and compares a position of the restored overlay pattern image with a position of an overlay pattern image not compared by the comparison unit, and which reads out a deviation between the two positions,
• wherein the comparison unit includes a database which provides at least one pre-stored overlay pattern images and
• wherein the comparison unit extracts one of the remaining overlay pattern images not compared with the overlay pattern image provided from the database, among the plurality of overlay patterns picked up by the pickup unit.

An apparatus for inspecting overlay patterns, comprising:

• an optical module which projects a plurality of neighboring overlay patterns formed on a wafer;
• a pickup unit which obtains a plurality of image signals corresponding to the plurality of overlay patterns projected from the optical module;
• a comparison unit configured to:
• generate a plurality of images including the plurality of overlay patterns from the image signals obtained at the pickup unit;
• compare an overlay pattern image corresponding to any one of the plurality of overlay patterns with a previously input overlay pattern image;
• and
• based on the comparison, extract at least a portion of the overlay pattern image identical or similar to the previously input overlay pattern image;
• a restoration unit which restores the extracted overlay pattern image in accordance with a predetermined overlay pattern;
• and
• a readout unit which calculates and compares a position of the restored overlay pattern image with a position of an overlay pattern image not compared by the comparison unit, and which reads out a deviation between the two positions,
• wherein the readout unit:
• divides the overlay pattern image restored by the restoration unit into X and Y axial directions;
• finds a central position of the divided overlay pattern image restored by the restoration unit;
• divides the overlay pattern image not compared by the comparison unit into X and Y axial directions;
• finds a central position of the divided overlay pattern image not compared by the comparison unit;
• compares the central position of the divided overlay pattern image restored by the restoration unit with the central position of the divided overlay pattern image not compared by the comparison unit;
• and
• calculates a correction value for the overlay patterns based on the comparison.

A method for inspecting overlay patterns, comprising the steps of:

• projecting a plurality of neighboring overlay patterns formed on a wafer;
• picking up the plurality of projected overlay patterns and obtaining image signals corresponding to the plurality of projected overlay patterns;
• generating images including the plurality of overlay patterns using the obtained image signals;
• comparing an overlay pattern image corresponding to any one of the plurality of overlay patterns with an overlay pattern image pre-stored at a database;
• extracting, based on the comparison, at least a portion of the overlay pattern image identical or similar to the previously input overlay pattern image;
• restoring the extracted overlay pattern image in accordance with a predetermined overlay pattern;
• calculating and comparing a position of the restored overlay pattern image with a position of an overlay pattern image not compared by the comparison unit;
• and
• reading out a deviation between the two positions.