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US 4,728,790 AGranted
Low-abberation spectrometer objective with high secondary electron acceptance
AssigneeSiemens Aktiengesellschaft
InventorErich Plies
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AssigneeSiemens Aktiengesellschaft
InventorErich Plies
Estimating the term…
The spectrometer objective of the invention is composed of a short focal length objective lens (OL) and a spectrometer-detector arrangement which is completely integrated in the magnetic lens. The working distance (L) has a decisive influence on the chromatic and spherical image defect of the objective lens (OL) which can be reduced with the arrangement of the invention and, thus, the diameter of the electron probe on the specimen (PR) can be substantially demagnified. An angle-independent accumulation of the secondary electrons (SE) are triggered such that the measuring location occurs according to the invention by imaging of the virtual source point (QS) of the secondary electrons (SE) into the center of a spherical opposing field which occurs in the spatial region between two spherical-symmetrical grid electrodes (K1 and K2).
A spectrometer for quantitative measurements of potentials in electron beam mensuration technology, comprising an electron beam source, an objective lens (OL) for focusing a primary electron beam (PE) from said source onto a specimen (PR), an electrostatic opposing field spectrometer which comprises an electrode arrangement (G1) for the extraction of secondary electrons (SE) triggered at the measuring location by the primary electron beam (PE), an electrode means (K1, K2) for generating an electrical opposing field which retards the secondary electrons (SE) from the specimen, and a detector for recording the secondary electrons (SE), characterized in that the opposing field electrode means comprises two spherical-symmetrical electrodes (K1, K2) which have potentials (V.sub.D, V.sub.E) which are selected such that a spherical-symmetrical opposing field builds up in the space between said electrodes;
A spectrometer for quantitative electron beam measurements comprising an objective lens for focusing a primary electron beam from an electron beam source onto a specimen, a retarding potential spectrometer which comprises a first electrode arrangement for the acceleration of secondary particles triggered at said specimen in the direction of said objective lens, a second electrode arrangement for the deceleration of said secondary particles, said second electrode arrangement comprises two spherical-symmetrical electrodes which have different potentials;
A spectrometer for quantitative electron beam measurements comprising an objective lens for focusing a primary electron beam from an electron beam source onto a specimen, a retarding potential spectrometer which comprises a first electrode arrangement for the acceleration of secondary particles triggered at said specimen in the direction of said objective lens, a second electrode arrangement for the deceleration of said secondary particles, said second electrode arrangement comprises two electrodes that form parts of the surface of two spheres having different radii;
Dependencies are inferred from the claim text.