Pattern defect inspection apparatus
US4731855A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 8, 1985 |
| Grant date | Mar 15, 1988 |
| Priority date | — |
| Expiry date | Apr 8, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/26
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A pattern defect inspection apparatus detects presence or absence of a defect in a pattern formed on a semiconductor wafer by scanning the pattern normally to the surface thereof by a coherent light beam of a predetermined spot size, detecting reflected diffraction lights generated thereby and processing the detected lights. It comprises an abnormal direction signal detector including photo-detectors having wide light receiving areas arranged in a plurality of spatial areas which the reflected diffraction lights from a normal pattern do not normally reach, a normal pattern detector including photo-detectors having large light receiving areas arranged in a plurality of spatial areas which the reflected diffraction lights from the normal pattern reach, and a defect discriminator for determining if the abnormal direction signals are due to a true defect or not in accordance with the signals from the abnormal direction signal detector and the normal pattern detector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.