Charged particle beam device with dynamic focus and method of operating thereof

Abstract

A retarding field scanning electron microscope is described. The microscope includes a scanning deflection assembly configured for scanning an electron beam over a specimen, one or more controllers in communication with the scanning deflection assembly for controlling the electron beam scanning pattern, and a combined magnetic-electrostatic objective lens configured for focusing the electron beam including an electrostatic lens portion. The electrostatic lens portion includes a first electrode with a high potential bias, and a second electrode disposed between the first electrode and the specimen plane with a potential bias lower than the first electrode, wherein the second electrode is configured for providing a retarding field. The microscope further includes a voltage supply connected to the second electrode for biasing the second electrode and being in communication with the controllers, wherein the controllers synchronize a variation of the potential of the second electrode with the scanning pattern.

Description

TECHNICAL FIELD OF THE INVENTION[0001]Embodiments of the present invention relate to a retarding field scanning microscope using a charged particle beam and to a method of imaging a specimen by scanning a charged particle beam.BACKGROUND OF THE INVENTION[0002]Charged particle beam apparatuses have many functions, in a plurality of industrial fields, including, but not limited to, critical dimensioning of semiconductor devices during manufacturing, defect review of semiconductor devices during manufacturing, inspection of semiconductor devices during manufacturing, exposure systems for lithography, detecting devices and testing systems. Thus, there is a high demand for structuring, testing and inspecting specimens within the micrometer and nanometer scale.[0003]Micrometer and nanometer scale process control, inspection or structuring is often done with charged particle beams, e.g. electron beams, which are generated and focused in charged particle beam devices, such as electron micro...

AI Technical Summary

Benefits of technology

This patent describes a scanning electron microscope that uses a special field to slow down and focus an electron beam on a specimen for image generation. The microscope includes a special lens that has both magnetic and electrostatic components, with the second electrode being biased to a lower potential to create a retarding field. This allows for precise control over the electron beam's scanning pattern. The microscope can be used for imaging a variety of specimens and offers improved resolution and accuracy compared to conventional microscopes. Additionally, this patent describes a method for using the microscope to generate images and a computer program for controlling the microscope's functions.

Problems solved by technology

However, the application of a high scanning speed is an additional challenge.

Such high voltages are difficult to switch with the required speed and furthermore require electrical insulation which is difficult to achieve for these high voltages.

Yet further, such electrodes represent relatively large capacitances, which are also difficult to switch quickly.

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