Method of inspecting microscopic surface defects
Automatic focusing method and apparatus utilizing contrasts of projected pattern
Pattern defect inspection apparatus
Method of and apparatus for checking geometry of multi-layer patterns for IC structures Patent #: 4791586
ApplicationNo. 641001 filed on 01/14/1991
US Classes:250/559.05, With imaging250/559.39, With comparison to reference or standard250/559.45, With defect discrimination circuitry356/394With comparison to master, desired shape, or reference voltage
ExaminersPrimary: Nelms, David C.
Assistant: Shami, F.
Attorney, Agent or Firm
Foreign Patent References
International ClassG01N 021/88
Foreign Application Priority Data1989-09-18 JP
AbstractA method and apparatus for detecting a defect in a circuit pattern by detecting a gray image signal from each of a plurality of circuit patterns as objects of inspection, which circuit patterns have been fabricated so as to be identical with one another, and detecting a defect as a difference of edge position between two circuit patterns by comparing the detected gray image signal of one circuit pattern with the detected gray image signal of another circuit pattern.