Method and device for producing an image

#This application relates to a method and a device for producing an image of an object using a particle beam; in the method or the device, the particle beam may be scanned over the object.

#A particle beam system may be designed, e.g., as an electron beam system or an ion beam system. The use of an electron beam system in particular is already very widespread. An electron beam system is used, e.g., to manufacture nanostructures. An example of an electron beam system is an electron beam microscope, which has been known for a long time, and using which an image of an object may be created. The two known types of electron beam microscopes are the scanning electron microscope and the transmission electron microscope. The scanning electron microscope is used to create high-resolution images of semiconductor structures, biological and mineralogical samples, and other samples.

#An electron beam system (also referred to as an electron beam device) such as the scanning electron microscope includes a particle beam generator in the form of an electron beam generator for producing an electron beam, an objective lens for focusing the electron beam on the object, and at least one detector for detecting electrons that are scattered on the object or that are emitted from the object. The electron beam produced by the particle beam generator is focused via the objective lens on the object to be investigated. Using a deflection device, the electron beam is guided in a scanning pattern over the surface of the object to be investigated. The electron beam is therefore scanned over the surface of the object. The electrons of the electron beam interact with the object. As a result of the interaction, electrons, in particular, are emitted from the object surface (“secondary electrons”), or electrons from the electron beam are reflected back (“backscattering electrons”). Secondary electrons and backscattering electrons may be detected using the detector. The detector detects a detector signal depending on the detected secondary electrons and backscattering electrons. The detector signal is used to create an image.

#The system described herein is explained below in greater detail with reference to exemplary embodiments using figures.

#FIG. 1 shows a schematic depiction of a particle beam device;

#FIG. 2 shows a schematic depiction of an electron beam device designed as a scanning electron microscope;

#Various embodiments of the system described herein will now be explained in general with reference to a particle beam device 1. FIG. 1 shows the schematic depiction of particle beam device 1. Particle beam device 1 includes a beam source 2 (beam generator), using which a particle beam is generated. The particle beam is introduced into a particle beam column (not depicted), and it is focused onto an object 5 using an objective lens 3. A scanning means 4 is provided in order to scan the particle beam over object 5. It is expressly pointed out that the relative placement of objective lens 3 and scanning means 4 is merely a schematic depiction. The actual placement of objective lens 3 and scanning means 4 relative to each other may be entirely different from that which is shown.

#The particle beam scanned over object 5 using scanning means 4 interacts with object 5 and generates interaction particles, which are detected via a detector (not depicted) and are used to create an image.

#Particle beam device 1 also includes a particle current measuring device 6, which is located between particle generator 2 and objective lens 3. As an alternative, it is provided that the particle current measuring device is integrated in beam generator 2. Particle current measuring device 6 is connected via a line 8 to an evaluation unit 7. In addition, evaluation unit 7 is connected via a line 9 to scanning means 4. It is also possible to use evaluation unit 7 to set a threshold value for the change in the particle current. If the change in the particle current exceeds this threshold value, this causes the particle beam to be returned, as described below.