1. Field of the Invention
The present invention relates to an inspection equipment used to inspect a semiconductor wafer having a predetermined device pattern formed therein, and the like.
2. Description of the Related Art
A semiconductor device is produced with a fine device pattern formed on a semiconductor wafer. In forming such a device pattern, dust or scratch on the semiconductor wafer surface will cause a defect. The semiconductor incurring such a defect is rejected as an unacceptable device, which will lower the yield at the semiconductor device production line.
Accordingly, to stabilize the yield of the production line at a high level, it is necessary to early find a defect caused by dust or scratch, locate the cause of the defect, and apply effective remedies to the manufacturing equipment and process.
If any of the produced semiconductor devices is found defective, an inspection equipment is used to examine what the defect is and classify the defect, and find out where in the manufacturing equipment and process the cause of the defect exists. What the defect is has been examined by an inspection equipment like an optical microscope. For identification, a defect is observed by magnifying its image.
Along with a higher degree of integration in a semiconductor device, a finer and finer device pattern has been demanded. Recently, a line width of less than 0.18 μm has been attained. Thus, the defect size has become so fine that it has become difficult for the conventional inspection equipment to examine what the defect is and classify the detect.