KR-102965368-B1 - REDUCTION OF IMAGE DRIFT IN A MICROSCOPY SYSTEM

Abstract

The present invention relates to a sample holder for a microscope system comprising a material having low thermal conductivity to reduce drift of the sample holder when inserted into a microscope. The present invention also relates to a cold trap for a microscope system comprising a sample holder, wherein the cold trap comprises at least partially a coating having high thermal emissivity to increase the thermal load between the sample holder and the cold trap. The present invention also relates to a microscope system comprising a first element configured to have a first temperature (T1), a second element configured to have a second temperature (T2), and a third element configured to have a third temperature (T3), wherein the third element is configured to be located at a plurality of different distances from the first element, and the microscope system is configured to at least image a sample and reduce drift of the image. The present invention also relates to a corresponding method.

Inventors

• 헤스털 닉 판
• 페르빔프 닉
• 크레이넌 뤼트

Assignees

• 에프이아이 컴파니

Dates

Publication Date

20260513

Application Date

20220502

Priority Date

20210630

Claims (19)

1. delete
2. delete
3. delete
4. delete
5. delete
6. delete
7. In a microscope system, A first element configured to have a first temperature (T1), A second element configured to have a second temperature (T2), and It includes a third element configured to have a third temperature (T3), said third element configured to be located at a plurality of different distances from the first element, and The above microscope system A microscope system configured to image at least a sample and reduce the drift of the image.
8. A microscope system according to claim 7, wherein the reduction of the drift of the image is 1% to 100%.
9. In claim 7, the first element comprises a sample holder, a microscope system
10. In claim 9, the sample holder comprises an elongated rod and a tip for holding a sample, an intermediate portion is provided between the rod and the tip, and the intermediate portion comprises a material having low thermal conductivity, a microscope system.
11. A microscope system according to any one of claims 7 to 10, wherein the second element comprises a high-emissivity component, and the high-emissivity component comprises at least partially a coating having high thermal emissivity to increase the heat load between the first element and the high-emissivity component.
12. A microscope system according to any one of claims 7 to 10, wherein the third element comprises a detector.
13. A microscope system according to any one of claims 7 to 10, wherein the second temperature is different from the first temperature and the third temperature is different from the first temperature.
14. In paragraph 13, the difference between the first temperature and the second temperature is 20 C and 1000 C-type, microscope system.
15. In paragraph 13, the difference between the first temperature and the third temperature is 20 C and 1000 C-type, microscope system.
16. A microscope system according to claim 10, wherein the thermal conductivity is 0.1 W/m/K to 100 W/m/K.
17. In claim 10 or 16, the sample holder comprises an ultra-low expansion (ULE) material, and the coefficient of thermal expansion of the ULE material is 10⁻⁹ / C and 100/ C-type, microscope system.
18. In claim 11, the microscope system comprising a coating having a thermal emissivity between 0.5 and 1.
19. In claim 11, the high-emissivity component comprises a cold trap, in a microscope system.

Description

Reduction of Image Drift in a Microscope System The present invention relates to the field of microscope systems. In particular, the present invention relates to a system for reducing image drift in a microscope system. More specifically, the present invention relates to a system for reducing thermal drift of a sample holder and a corresponding method. Microscope systems are widely used not only for observing samples but also for preparing, processing, and manipulating them. In a typical microscope system, a beam of particles is directed toward a sample supported in a sample holder, and the particles in the beam interact with the sample to induce various emissions from the sample that can be captured by various detectors. Depending on the intended use and resolution of the microscope system, the beam may contain charge-neutral particles, such as photons, or charged particles, such as electrons or ions. The microscope system may also include an optical device (which may be electromagnetic, electrostatic, or magnetostatic) that directs and focuses the beam to a specific location on the sample. Electrons and ions can provide higher resolution due to their shorter wavelengths (because electrons and ions have greater mass compared to photons). However, charged particles may need to be accelerated to high kinetic energies to achieve resolution comparable to or better than that of an optical microscope. Since higher energy can result in a larger cross-sectional area for interacting with neutral molecules, these systems are typically operated under vacuum conditions in vacuum columns or vacuum chambers. In some vacuum chambers, a cold trap may be provided to prevent contamination of the vacuum pump and/or sample by vapor. The temperature of the cold trap can generally differ from the temperature of the vacuum chamber. Therefore, heat flow may occur between the cold trap and the sample holder (which may be in thermal equilibrium with the vacuum chamber). Detectors for charged particle microscope systems typically use -40 to reduce dark current and improve signal-to-noise ratios. It can be cooled to a low temperature of C. Additionally, the detector is retractable, so it can be positioned for detection and retracted otherwise. The expansion and contraction of the detector can cause significant temperature changes in the sample holder. For example, when the sample holder (containing the sample) is inserted into the vacuum chamber, the beam can be aligned with the sample and the microscope system prepared for subsequent operation. After equilibration, the sample holder is at the ambient temperature of the vacuum chamber, and there may be a cold trap inside the chamber. Later, cooled detector(s) can be placed near the sample holder to capture emissions resulting from the interaction between the beam and the sample. The placement of cooled detector(s) can cause changes in the heat flow between the sample holder and the detector(s) due to variations in the distance of the detector(s). The detector can also alter the heat flow between the sample holder and the cold trap by shielding the cold trap at least partially. Therefore, changes in the distance from the detector(s) can lead to an overall change in the heat flow from/to the sample holder. This can cause thermal drift. As a result, the alignment of the image may become disrupted, and the image may begin to drift. The magnitude of the drift can depend on the temperature difference between the low-temperature detector(s) and the sample holder temperature prior to detector placement. In a typical system, the drift can be as large as, for example, 200 nm, while the typical expected resolution can be, for example, 1 nm. The system must then be allowed to stabilize to a new equilibrium state, which can take, for example, one hour. This can lead to inefficiency in system operation. Embodiments of the present technology aim to improve the efficiency of a microscope system by reducing image drift caused by thermal variations in the sample holder. This may be particularly relevant to microscope systems used in the fabrication and/or machining of micro or nanostructures, where such drift can have a particularly negative impact. Embodiments of the present technology will now be discussed with reference to the attached drawings. Figure 1 illustrates the vacuum chamber of a microscope system; FIG. 2 illustrates a vacuum chamber in which a detector is placed; FIG. 3 illustrates a sample holder for a microscope system; FIG. 4 illustrates a cold trap of a microscope system with a high-emissivity coating; and Figure 5 shows a cold trap placed inside a vacuum chamber. FIG. 1 illustrates a perspective view of a vacuum chamber (10) of a microscope system. The vacuum chamber (10) may house a sample holder (100) configured to hold a sample (not shown) at its tip (110). The sample holder (100) may be configured to be inserted into and/or retracted from the vacuum chamber (10). The vacuum cham