BACKGROUND OF THE INVENTION

Charged particle microscope systems have been developed to allow scientists to investigate and gather information on how microscopic systems work. In pursuit of such knowledge, scientists push the limits of what current charged particle microscope systems are able to investigate. This is especially true on the atomic and nanoparticle evaluation where, a number of new obstacles to evaluation are experienced due to the size of the objects being investigated. For example, because atoms and nanoparticles are so small that even with the best magnification optics, the majority of an area scanned by a charged particle beam during investigation of such atoms/nanoparticles necessarily corresponds to voids and/or structures other than the atoms/nanoparticles being investigated. This means that current charged particle microscope systems waste time obtaining irrelevant data when evaluating atoms/nanoparticles. Additionally, as the nature of atoms is to create a large void between their nuclei and other atomic structures relative to their size, this problem of scanning spaces between atoms cannot be fixed by increased magnification alone.

Moreover, due to the reduced size of the structures irradiated during evaluation of atoms/nanoparticles, the samples containing the atoms/nanoparticles are more susceptible to damage caused by such irradiation. To compensate for such damage, current charged particle microscope systems reduce the beam strength and length of time the beam irradiates individual structures. While this reduction of bean strength that dwell time reduces the damage to the sample, it also reduces the amount of information obtained during each scan. Thus, to obtain statistically meaningful data current charged particle microscope systems are forced to conduct many repetitive scans (10×-1000×) of a sample before they are able to cumulatively obtain statistically significant data for the atoms/nanoparticles being investigated. This means that current evaluations of such atom/nanoparticle samples can take hours or days.

This repetition further complicates the evaluation of atoms and nanoparticles, as individual shifts between scan instances cause a drift/inaccuracy in the data cumulatively obtained across many scans. Accordingly, better methods for evaluating atoms and nanoparticles are desired to address the time, damage, and accuracy issues of present systems.

SUMMARY OF THE INVENTION

Methods for drift corrected, fast, low dose, adaptive sample imaging with a charged particle microscopy system according to the present disclosure include scanning a surface region of a sample with a charged particle beam to obtain a first image of the surface region with a first detector modality, and then determining a scan strategy for the surface region. The scan strategy comprises a charged particle beam path, a first beam dwell time associated with at least one region of interest in the first image, the first beam dwell time being sufficient to obtain statistically significant data from a second detector modality, and at least a second beam dwell time associated with other regions of the first image, wherein the first beam dwell time is different than the second beam dwell time. The method further includes scanning the surface region of the sample according to the determined scan strategy to obtain first data from the second detector modality and second data from the first modality.

Systems for investigating a sample with a charged particle microscopy system according to the present disclosure comprise a sample holder configured to hold a sample, a charged particle source configured to emit a beam of charged particles towards the sample, an optical column configured to cause the beam of charged particles to be incident on the sample, and one or more detectors configured to detect charged particles of the charged particle beam and/or emissions resultant from the charged particle beam being incident on the sample. According to the present disclosure the one or more detectors include at least a first detector of a first modality and a second detector of a second modality that is different from the first. The systems also include one or more processors, and a memory storing computer readable instructions that, when executed by the one or more processors, cause the corresponding system to perform one or more steps of methods according to the present disclosure.

