US-20260128251-A1 - PREVENTING ESD IN PRT SEM DISCHARGES

Abstract

The present invention relates, inter alia, to a method for influencing a charge state of a sample, comprising directing a charged particle beam onto the sample for the purpose of analyzing and/or processing the sample, wherein the particles of the particle beam are accelerated onto the sample by a first acceleration voltage and result in charging of the sample, and directing the charged particle beam onto the sample for the purpose of influencing the charging of the sample, wherein the particles of the particle beam are accelerated onto the sample by a second, changed acceleration voltage amounting to at least 15% of the first acceleration voltage.

Inventors

• Hans Hermann Pieper
• Daniel Alexander Emmrich
• Lalitha Kodumudi Venkataraman
• Claudia Kroeckel
• Katharina Bitsch
• Rene Kullock

Assignees

• CARL ZEISS SMT GMBH

Dates

Publication Date

20260507

Application Date

20251219

Priority Date

20230622

Claims (20)

1. 1 . A method for influencing a charge state of a sample, comprising: providing a scanning probe microscope, SPM, tip; producing an electrically conductive connection between the sample and the SPM tip for the purpose of influencing the charge state; and directing a particle beam onto the sample for the purpose of analyzing and/or processing the sample; wherein producing the electrically conductive connection is at least partly based on a measured and/or expected charge state of the sample.
2. 2 . A method for influencing a charge state of a sample, comprising: providing a scanning probe microscope, SPM, tip; producing an electrically conductive connection between the sample and the SPM tip for the purpose of influencing the charge state; wherein the method takes place in a combined scanning probe microscope-scanning electron microscope device.
3. 3 . The method of claim 1 , wherein the method takes place in a combined scanning probe microscope-scanning electron microscope device.
4. 4 . The method of claim 3 , wherein producing the electrically conductive connection takes place by bringing the SPM tip closer to a surface of the sample.
5. 5 . The method of claim 4 , wherein the bringing closer takes place at least partly on the basis of detecting at least one process parameter.
6. 6 . A method for monitoring a charge state of a sample, comprising: detecting a process parameter associated with the charge state of the sample, and wherein the process parameter was recorded by a scanning electron microscope, SEM, a scanning probe microscope, SPM, and/or an x-ray detector; determining the charge state of the sample at least partly on the basis of the process parameter; and initiating a method for influencing the charge state of the sample if a predetermined charge threshold value of the sample is exceeded.
7. 7 . The method of claim 6 , wherein the determining takes place at least partly by way of a previously known relationship of the process parameter and the charge state of the sample.
8. 8 . The method of claim 6 , wherein the determining is at least partly based on detecting an interaction between a tip of the SPM and the sample.
9. 9 . A method for influencing a charge state of a sample, comprising: directing a charged particle beam onto the sample for the purpose of analyzing and/or processing the sample, wherein the particles of the particle beam are accelerated onto the sample by a first acceleration voltage and result in charging of the sample; and directing the charged particle beam onto the sample N times for the purpose of influencing the charging of the sample, wherein the particles of the particle beam are accelerated onto the sample by a respective second to (N+1)-th acceleration voltage, wherein: N is greater than or equal to two; and the second acceleration voltage amounts to at least 15% of the first acceleration voltage; wherein the second acceleration voltage differs from the first acceleration voltage.
10. 10 . The method of claim 9 , wherein the second acceleration voltage is less than the first acceleration voltage.
11. 11 . The method of claim 9 , wherein the analyzing comprises recording x-ray beams generated in the sample by the particle beam.
12. 12 . The method of claim 1 , wherein the first acceleration voltage amounts to at least 1 kV, more preferably at least 3 kV and most preferably at least 4 kV.
13. 13 . The method of claim 1 , wherein the second acceleration voltage amounts to at least 30%, preferably at least 40%, particularly preferably at least 50% and most preferably at least 60% of the first acceleration voltage for analyzing.
14. 14 . The method of claim 1 , wherein the particle beam for the analyzing amounts to a particle current of at least 5 pA, preferably at least 1 nA and most preferably at least 150 nA.
15. 15 . The method of claim 1 , wherein the particle current during the analyzing and/or processing of the sample is substantially equal to the particle current during the influencing of the charging of the sample.
16. 16 . The method of claim 1 , wherein the N-th acceleration voltage amounts to at least 30%, preferably at least 40%, particularly preferably at least 50%, very particularly preferably at least 60% and most preferably 70% of the (N−1)-th acceleration voltage.
17. 17 . The method of claim 1 , wherein the N-th acceleration voltage is at least 250 V less than the (N−1)-th acceleration voltage and/or wherein the N-th acceleration voltage is at most 4 kV less than the (N−1)-th acceleration voltage.
18. 18 . The method of claim 1 , wherein the directing N times takes place successively and reducing the respective acceleration voltage at least twice is carried out in the process.
19. 19 . The method of claim 18 , wherein the reducing at least twice takes place by the same absolute value in each case.
20. 20 . The method of claim 18 , wherein the reducing at least twice takes place in such a way that the reduction absolute values follow a logarithmic profile.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of and claims benefit under 35 U.S.C. § 120 from PCT Application No. PCT/EP2024/067474, filed on Jun. 21, 2024, which claims priority from German Application No. 10 2023 205 886.3, entitled “Verhindern von ESD in PRT SEM Entladungen,” filed on Jun. 22, 2023. The entire contents of each of these earlier applications are incorporated herein by reference. TECHNICAL FIELD The present invention relates to methods, a computer program and a device for influencing a charge state of a sample. BACKGROUND Analyzing and/or processing a lithographic mask (also referred to herein as mask) by use of a particle beam has been known for a relatively long time. For example, the particle beam may comprise an electron beam, ion beam and/or a photon beam which is provided in a defined manner on the mask for the purpose of analyzing and/or processing the mask. Providing the particles of the particle beam on the mask allows various interactions to be generated, which can enable various analysis processes and/or processing processes of the mask. In this regard, particle beam-based analyzing and/or processing of a mask may comprise a wide variety of methods. For example, the particle beam-based processing may comprise a particle beam-induced etching and/or deposition, within the scope of which material of a mask is removed or generated locally. For example, this may comprise an electron beam-induced etching and/or deposition. Furthermore, a defined photon irradiation of the mask may also be required, e.g., for processing the mask (e.g., in the case of a laser-induced reaction). Examining a mask using a particle beam may, for example, comprise an image of the mask being recorded with the aid of the particles in the particle beam (e.g., as occurs with the aid of an electron beam in the case of a scanning electron microscope (SEM)). Particle beam-based analyzing and/or processing of a mask using a particle beam is now used for various applications in industry. In other applications, it may also be necessary to remove foreign bodies from the surface of a mask, at least partly on the basis of using a tip of a scanning probe microscope. For example, in the semiconductor industry, increasingly smaller structures are produced on a wafer in order to ensure an increase in integration density. Among the methods used here for the production of the structures are lithography methods which image these structures onto the wafer. The lithography methods may include, for example, photolithography, ultraviolet (UV) lithography, DUV lithography (i.e., lithography in the deep ultraviolet spectral region), EUV lithography (i.e., lithography in the extreme ultraviolet spectral region), x-ray lithography, nanoimprint lithography, etc. Masks are usually used here as lithography objects (e.g., photomasks, exposure masks, reticles, stamps in the case of nanoimprint lithography, etc.), which comprise a pattern in order to image the desired structures onto a wafer, for example. As the integration density increases, so do the demands in respect of the mask production (e.g., as a result of the accompanying reduction in the structure dimensions on the mask or as a result of the greater material requirements in lithography). Thus, mask production processes are becoming ever more complex, time-consuming and expensive. It is not always possible to avoid mask errors (e.g., defects). Thus, the mask errors are usually repaired by way of particle beam-based processing since they can only be repaired, e.g., in particle beam-based fashion on account of their small dimensions. Furthermore, it may be necessary to examine masks using a particle beam, for example, in the semiconductor industry. For example, the repair of mask errors may thus require image recordings of the mask errors or the repair location to be effected using a particle beam (e.g., for a high-resolution SEM image). Other industrial purposes may also require a sample to be analyzed and/or processed using a particle beam. For example, this may be carried out for the analysis (e.g., a defect analysis) of a sample which may comprise, e.g., a microchip, a wafer, a biological sample, etc. In some cases, an analysis of a sample may also comprise an AFM image recording of the sample. Processing the sample may comprise, e.g., removing a particle (e.g., a foreign particle) from the sample (e.g., in the context of a so-called particle pick process). However, the masks to be analyzed and/or processed using the particle beam may have an (unwanted) electrostatic charging. Disadvantageous effects may be caused by the (unwanted) electrostatic charging. For example, the (unwanted) electrostatic charging may result in the particle beam being deflected away from the intended point of incidence on the mask. Furthermore, the electrostatic charging may also result, e.g., in a particle beam-based reaction not achieving the desired effect. Thus, the (unwant