Ultrafine pattern discrimination using transmitted/reflected workpiece images for use in lithography inspection system
View Patent ↗A technique for discriminating a specific pattern, such as an assist pattern, from an integrate circuit pattern of a workpiece by using transmission and reflection images of the workpiece pattern is disclosed. A pattern discrimination device includes an optical image acquisition unit for acquiring a transmissive image of a workpiece having a pattern and a reflective image of the workpiece pattern simultaneously, and a specific pattern detection unit which detects for extraction a specific pattern from among pattern shapes of the transmissive and reflective images in conformity with a distinguishing condition of the specific pattern. A workpiece pattern inspection apparatus using the device is also disclosed.
1. A pattern discrimination device comprising:
an optical image acquisition unit configured to acquire both a transmissive image of a workpiece having a pattern and a reflective image of the workpiece pattern at a time; and
a specific pattern detection unit configured to distinctly detect a specific pattern from among pattern shapes of the transmissive and reflective images in conformity with a discrimination condition of the specific pattern,
wherein the discrimination condition of the specific pattern is based on the amount the size of the transmission image is smaller relative to the size of the reflection image for a cut pattern, or, alternatively, the amount the size of the reflection image is smaller relative to the size of the transmission image for a residue pattern.
2. The device according to claim 1 , wherein the specific pattern is an assist pattern.
3. A workpiece inspection apparatus comprising:
an optical image acquisition unit configured to acquire both a transmissive image of a workpiece having a pattern and a reflective image of the workpiece pattern at a time;
a specific pattern detection unit configured to distinctly detect a specific pattern from among pattern shapes of the transmissive and reflective images in conformity with a discrimination condition of the specific pattern;
a specific inspection execution region setup unit configured to set the specific pattern in a specific inspection execution region; and
a comparison judgment unit configured to perform, in the specific inspection execution region, pattern inspection of an optical image acquired by said optical image acquisition unit,
wherein the discrimination condition of the specific pattern is based on the amount the size of the transmission image is smaller relative to the size of the reflection image for a cut pattern, or, alternatively, the amount the size of the reflection image is smaller relative to the size of the transmission image for a residue pattern.
4. The apparatus according to claim 3 , wherein the specific pattern is an assist pattern and wherein the specific inspection execution region is an area with decreased sensitivity, called a desense area.
5. A workpiece inspection apparatus comprising:
an optical image acquisition unit configured to acquire both a transmissive image of a workpiece having a pattern and a reflective image of the workpiece pattern at a time;
a comparison judgment unit configured to perform pattern inspection of an optical image acquired by said optical image acquisition unit to thereby extract therefrom a portion which is deemed to be a defect;
a specific pattern detection unit configured to distinctly detect at the portion deemed to be the defect a specific pattern from among pattern shapes of the transmissive and reflective images in a way pursuant to a discrimination condition of the specific pattern; and
a specific inspection execution unit configured to execute specific inspection if the portion deemed to be the defect is the specific pattern,
wherein the discrimination condition of the specific pattern is based on the amount the size of the transmission image is smaller relative to the size of the reflection image for a cut pattern, or, alternatively, the amount the size of the reflection image is smaller relative to the size of the transmission image for a residue pattern.
6. The apparatus according to claim 5 , wherein the specific pattern is an assist pattern and wherein the specific inspection is desense processing.