CN-122016764-A - Spectroscopic or microscopic device and method of operating the same

Abstract

The spectroscopic or microscopic device is operated by measuring the intensity distribution of the laser beam guided along a trajectory through the device, the intensity distribution being measured at a reference position in the trajectory. The shape of the laser beam is configured based on the measured intensity distribution.

Inventors

• C. Slade
• M. Islam
• D. Devadasan
• S. Bacon

Assignees

• VG系统有限公司

Dates

Publication Date

20260512

Application Date

20251111

Priority Date

20241111

Claims (20)

1. 1. A method of operating a spectroscopic or microscopic device, the method comprising: Measuring an intensity distribution of a laser beam guided in a vacuum along a trajectory passing through the device, the intensity distribution being measured at a reference position in the trajectory by irradiating a profile-measuring element with the laser beam, wherein the profile-measuring element intersects the laser beam at the reference position, and The shape of the laser beam is configured based on the measured intensity distribution.
2. 2. The method of claim 1, wherein the reference location is located a reference distance from a focal point of the laser beam.
3. 3. The method of any preceding claim, wherein the method further comprises ablating material from a portion of a sample surface by irradiating the portion with the laser beam after the step of configuring the shape of the laser beam based on the measured intensity distribution.
4. 4. A method according to claim 3, wherein during the step of ablating material from a portion of a sample surface, the portion of the sample surface intersects the laser beam at the reference location.
5. 5. The method of claim 3 or claim 4, further comprising, after the step of ablating material from a portion of the sample surface, performing a spectroscopic or microscopic analysis of at least a portion of the ablated portion, optionally wherein the spectroscopic analysis comprises X-ray photoelectron spectroscopy, ultraviolet electron spectroscopy, auger electron spectroscopy, secondary ion mass spectrometry, and/or laser induced breakdown spectroscopy, optionally wherein the microscopic analysis comprises electron microscopy (TEM or SEM).
6. 6. The method of claim 5, further comprising, after the step of performing spectroscopic or microscopic analysis, performing one or more further cycles of ablation and analysis, each cycle comprising the step of further ablating material from the region of the sample surface, followed by the step of performing spectroscopic or microscopic analysis on at least a portion of the further ablated portion, and after performing the one or more further cycles, determining a depth profile of a composition of at least a portion of the ablated portion of the sample surface, optionally wherein the depth profile is quantitative.
7. 7. The method of claim 5 or claim 6, wherein the step of spectrally or microscopically analyzing at least a portion of the ablated section comprises directing an imaging beam along the trajectory within the device to the ablated section, wherein during the step of spectrally or microscopically analyzing the imaging beam intersects the ablated section at an imaging position in the trajectory of the imaging beam, optionally wherein the imaging beam comprises an ultraviolet beam, an X-ray beam, an electron beam, an ion beam, and/or a laser beam.
8. 8. The method of claim 7, wherein the method further comprises co-aligning the imaging beam and the laser beam such that the imaging position coincides with the reference position.
9. 9. The method of any preceding claim, wherein configuring the shape of the laser beam comprises configuring the laser beam to achieve a substantially flat top cap or flat top intensity profile at the reference location.
10. 10. The method of any preceding claim, wherein configuring the laser beam comprises controlling one or more optical elements configured to shape the laser beam.
11. 11. The method of claim 10, wherein the one or more optical elements comprise diffractive optical elements and/or refractive optical elements.
12. 12. The method of any preceding claim, wherein the profile measurement element comprises a laser sensitive material or a laser sensor, optionally wherein the profile measurement element comprises the laser sensitive material coated on a sensor device, optionally wherein the laser sensor or sensor device comprises one or more cameras, optionally wherein the laser sensitive material, sensor device and/or laser sensor is compatible with Ultra High Vacuum (UHV) conditions.
13. 13. The method of claim 12, wherein the profile-measuring element comprises a laser-sensitive material, wherein measuring the intensity distribution of the laser beam at the reference location comprises detecting a change in or emission from the laser-sensitive material when the laser-sensitive material is irradiated with the laser beam, optionally wherein the intensity of the emission from the laser-sensitive material is proportional to the intensity of the laser beam irradiating it.
14. 14. The method of claim 12 or claim 13, wherein the laser sensitive material comprises a luminescent material configured to emit photons when irradiated with the laser beam, optionally wherein the luminescent material is a phosphorescent material or a fluorescent material, optionally wherein the luminescent material is an up-converting anti-stokes phosphor, optionally for converting infrared laser light into visible light.
15. 15. The method according to any one of claims 8 to 14, wherein the step of co-aligning the imaging beam and the laser beam comprises detecting an illumination of the profile-measuring element by the imaging beam and/or detecting an illumination of the profile-measuring element by the laser beam, optionally wherein during the step of co-aligning the imaging beam and the laser beam the profile-measuring element intersects the laser beam at the reference location and the imaging beam at the imaging location.
16. 16. The method of claim 15 when dependent on any of claims 13 to 15, wherein (i) the profile-measuring element comprises a laser-sensitive material, wherein the laser-sensitive material is configured to change or produce emissions upon illumination with the imaging beam, and/or wherein (ii) the profile-measuring element comprises the laser sensor, wherein the laser sensor is configured to detect illumination of the imaging beam.
17. 17. The method according to any one of claims 3 to 8, wherein after the step of measuring the intensity distribution, the method comprises (i) positioning the sample and/or the profile-measuring element and/or (ii) redirecting the laser beam, whereby during the step of ablating material from a portion of the sample surface the region of the sample surface intersects the laser beam at the reference location.
18. 18. A method according to any preceding claim, wherein the profile-measuring element is arranged on a sample stage during the step of measuring an intensity distribution.
19. 19. The method of claim 18, wherein the sample stage is configured to absorb or dissipate heat generated by the profile measurement element when the profile measurement element is disposed on the sample stage, optionally wherein the sample stage comprises a heat sink configured to receive heat generated by the profile measurement element when the profile measurement element is disposed on the sample stage.
20. 20. The method of claim 18 or claim 19 when dependent on claim 17, wherein during the step of measuring the intensity distribution, the sample is arranged on the sample stage, Wherein after the step of measuring the intensity distribution, the method further comprises (i) moving the sample and the profile-measuring element relative to the reference location by moving the sample stage, and/or (ii) redirecting the laser beam to move the reference location relative to the sample and the profile-measuring element, such that during the step of ablating at least a portion of the sample surface, the portion of the sample surface intersects the laser beam at the reference location.

Description

Spectroscopic or microscopic device and method of operating the same Technical Field The present invention relates to a microscope device or spectroscopic device and a method of operating such a device. Background The accurate and reliable spectral analysis or microscopic analysis of the solid body, the surface and any subsurface buried interface is critical to solving the manufacturing quality and characteristics of technically important materials and equipment, developing novel multifunctional materials and understanding material failure. Widely used and highly developed surface chemistry analysis methods include spectroscopic techniques and microscopic techniques. Spectroscopic techniques may involve detection of a surface with electromagnetic radiation, electron beams, ions or laser beams. Microscopy may involve probing the surface with an electron beam. Well-known spectroscopic techniques include, for example, X-ray photoelectron spectroscopy (XPS), auger Electron Spectroscopy (AES), secondary Ion Mass Spectrometry (SIMS), laser Induced Breakdown Spectroscopy (LIBS). Well known microscopy techniques may be X-ray or electron microscopy. Well known electron microscopy techniques include, for example, scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The two most widely used and developed surface chemistry analysis methods are electron spectroscopy techniques, X-ray photoelectron spectroscopy (XPS) and Auger Electron Spectroscopy (AES). XPS is an optoelectronic spectroscopy method in which the electron core energy level and valence band spectrum from an atom in a solid is obtained by irradiating the material with an X-ray beam. The chemical state information is extracted from the spectrum in the form of electron binding energy shifts due to local chemical environmental changes. AES is similar to XPS but is based on analyzing auger electrons emitted as part of the relaxation process after excitation of the core energy level. For AES, excitation occurs because the incident radiation is X-rays or an electron beam. Often, it is important to determine the chemical composition at a depth greater than the XPS/AES analysis depth. To achieve this, material must be removed from the surface and XPS/AES analysis repeated on the new surface revealed by the material removal. This cycle of material removal and XPS/AES analysis was continued until the chemical composition had been recorded for the depth of interest. The elemental composition of each level is calculated and plotted as a function of the number of cycles (referred to as the depth profile). If depth is measured, assuming a constant material removal rate, a depth profile can be plotted for chemical composition as a function of etched depth. In XPS/AES depth profile analysis, ion beam bombardment is typically performed with an ion gun mounted in a spectrometer to effect material removal. The ion gun may generate a single-atom ion beam or a (multi-atom) cluster ion beam. The ion beam is aligned with an X-ray spot (for XPS) or an electron beam (for AES) on the surface of the sample, allowing a cyclic depth profile analysis process to be performed. Ion guns accelerate ions to high energies that, once striking a surface, have sufficient energy to remove surface atoms in a process known as sputtering. However, many materials have ion beam sensitivity. This means that the sputtering process damages the underlying surface, resulting in a change in the XPS/AES through depth profile recording chemistry. In compounds, this may take the form of sputtering one element more than the other, known as preferential sputtering, and is particularly common for inorganic materials. For polymeric materials, ion beams break down the molecular structure in addition to preferentially sputtering elements such as oxygen from the polymer. Thus, for ion beam sensitive materials, the ability of XPS/AES to provide accurate quantitative composition information may be compromised and incorrect chemical compositions may be recorded throughout the XPS/AES sputter depth profile. In addition, the degree of preferential sputtering varies depending on the ion beam conditions and the material composition. The extent of preferential sputtering cannot be reliably predicted for any new material or ion beam conditions. Thus, when analyzing the depth profile of a potentially ion beam sensitive material, an analyst cannot know whether preferential sputtering is changing the apparent composition of the collected depth profile. For a technique that is considered to be able to provide an accurate chemical composition, it is a significant problem that the incorrect composition recorded during depth profile measurement and the inability to know whether the studied material is present or not. Clustering the ion beam enables significantly reduced damage to most thermal polymers during depth profile analysis. In addition, it has been demonstrated that clustered ion beams reduce but do