Patent · US Expired

Method and apparatus for light span microscopic dark-field display of objects

US4720191A · kind A · utility

16Cited by

2References

11Claims

0Family size

Assignee

Carl Zeiss Stiftung · DE

Inventors

Augustin Siegel · Oberkochen, DE
Peter Seidel

Key dates

Filing date	Nov 17, 1986
Grant date	Jan 19, 1988
Priority date	—
Expiry date	Nov 17, 2006

Classification

Technology area (CPC G)Physics
CPC primaryG01N2021/9563
WIPO fieldMeasurement
WIPO sectorInstruments

Abstract

A method used for the inspection of semiconductor structures under a light scan microscope which scans the surface of the wafer or other specimen (12) with a beam of light which is focused in spot form by the objective (18). In order to produce a dark-field image in which the linear semiconductor structures of the wafer are suppressed and only defects and particles of dirt are visible, the signals of four detectors (10a-10d) arranged outside the illuminating aperture of the objective within the channel of the dark-field ring condenser (6) are subjected to a logical "and" operation.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.