Detection System and Detection Method for Determining a Semiconductor Structure

Abstract

A detection system (1) for determining a semiconductor structure. The detection system has an ion beam source (2) for spatially resolving and displaying the structure to be determined with an ion beam (3). Further, the secondary ion detection device (12) includes a mass spectrometer (13). The mass spectrometer (13) is capable of measuring the mass-to-charge ratio of ions within a given bandwidth.

Description

[0001] This application claims priority to U.S. Provisional Application No. US 62 / 689,329 and German Patent Application No. DE 10 2018 212 403.5, the contents of which are incorporated herein by reference. Technical Field

[0002] The present invention relates to a detection system for determining a semiconductor structure. Further, the present invention relates to a detection method for determining a semiconductor structure. Background Art

[0003] A detection system and a detection method for determining a 3D semiconductor structure are known from US2007 / 0221843 A1 and from US2009 / 0114840 A1, and the detection system and the detection method are further known from "Helium Ion Microscopy, Nanoscience and Technology" (G. Hlawacek and A. (eds.), published by Springer International Publishing, Switzerland, in 2016 (G. Hlawacek and A. (eds.), Helium Ion Microscopy, Nanoscience and Technology, Springer International Publishing, Switzerland, 2016). WO 2008 / 152 132A2 discloses an apparatus and a method for performing secondary ion mass spectrometry. Summary of the Invention

[0004] It is an object of the present invention to improve such a detection system for determining a semiconductor structure, in particular for determining a 2D or 3D semiconductor structure.

[0005] This object is achieved by a detection system having the following features. A detection system for determining a semiconductor structure, having an ion beam source for spatially resolved imaging of the structure to be determined with an ion beam; having a secondary ion detection device; wherein the secondary ion detection device includes a mass spectrometer; and wherein the mass spectrometer is capable of simultaneously measuring the ion mass-to-charge ratio within a given bandwidth.

[0006] It has been recognized that using a mass spectrometer to simultaneously measure the ion mass-to-charge ratio within a given bandwidth, in combination with an ion beam source to generate secondary ions to be detected by the mass spectrometer, provides a powerful tool for determining semiconductor structures. The bandwidth within which the simultaneous measurement of the ion mass-to-charge ratio is accomplished by the mass spectrometer is the ion mass-to-charge ratio band between the lower boundary value of the ion mass-to-charge ratio and the upper boundary value of the ion mass-to-charge ratio. The system can be used to determine 2D and / or 3D structures. The system is capable of placing a well-defined restricted ion beam on the object or sample to be determined. In addition, the system can correlate on the one hand high-resolution secondary ion imaging with on the other hand the analytical information obtained by mass spectrometry. To this end, the system can include secondary electron imaging optics. The secondary ion mass spectrometer involved here provides the possibility of simultaneously tracking different ion mass-to-charge ratios and thus gives corresponding information about the different materials and / or elements and / or isotopes present in the sample region. It has also been recognized that the results of such a detection system are not affected by the use of a low-current ion beam, which can have a high spatial resolution and also a very small focal diameter. The spatial resolution can be better than 100 nm, better than 50 nm and can be better than 20 nm. The focal diameter of the ion beam can be less than 10 nm, less than 5 nm, less than 2 nm, less than 1 nm and can even be less than 0.5 nm. The detection system can be part of a device for inspecting and / or removing defects in the determined semiconductor structure. The detection system can be used to inspect specific structures, such as for the detection and inspection of high aspect ratio (HAR) contact coils. Such detection and inspection steps can be carried out during the manufacturing process of the corresponding semiconductor structure.

[0007] The detection system according to the present invention has a wide range of applications, some of which are discussed below:

[0008] One application is to use secondary ion mass spectrometry (SIMS) to measure the critical dimension (CD), the range of which varies as the complexity and range of the materials used in semiconductor devices increase. Due to the use of a mass spectrometer, the detection system is able to distinguish elements according to mass. This can be used to complete classical CD measurements of semiconductor devices that do not produce any elemental / chemical information. The secondary electron yield in traditional ion microscopy only provides a gray scale for each element for qualitative analysis.

[0009] A further application of the detection system according to the present invention is organic thin film characterization. This application is directed to Directed Self-Assembly (DSA) for wafer patterning. Such DSA vapor typically utilizes block copolymers to form structures with typical dimensions in the range of 10 nm to 100 nm (nanoscale). In the development of methods using DSA, it is very important to distinguish different types of organic polymers at the nanoscale. The detection system according to the present invention has the ability to directly distinguish different types of polymers using characteristic fingerprints measured by a mass spectrometer.

[0010] A further application of the detection system is single and buried defect detection. Detecting and analyzing the chemical composition of single defects on a wafer is very important for finding the source of these defects. In addition, the detection system can be used to determine chemical information about buried defects and the surrounding layers.

[0011] A further application of the detection system is etch residue characterization. This analysis of etch residues on a wafer provides valuable information. In particular, the stoichiometric changes in the etch chemistry are crucial for determining the cause of incomplete / defective etching or defective subsequent processing steps, which are caused by etch residues in confined volumes such as trenches, holes, corners, etc. Using a detection system according to the present invention with high spatial resolution and / or high surface sensitivity enables consultation of the stoichiometric changes of various device topologies.

[0012] In one embodiment, the mass spectrometer is capable of continuously measuring the ion mass-to-charge ratio within the given bandwidth. The above-described setting of the mass spectrometer capable of continuously measuring the ion mass-to-charge ratio further enhances the information output of the detection system. In the selected mass-to-charge ratio bandwidth, all ion mass-to-charge ratios present therein can be detected simultaneously. The selected ion mass-to-charge ratio bandwidth can include a bandwidth capable of simultaneously detecting elemental silicon, titanium, copper, selenium, tellurium, and antimony. The resulting mass bandwidth can be in the range between 1 u (unified atomic mass unit) and 500 u.

[0013] In one embodiment, the secondary ion detection device includes a secondary electron detection unit. The above-described secondary electron detection unit is capable of performing secondary ion detection with high precision and high efficiency. The useful yield, that is, the ratio between the number of secondary ions that can be measured by the detection system on the one hand and the number of sputtered particles generated by the ion beam on the other hand, can be high. The useful yield range can be from 10 -5 to 0.1.

[0014] In one embodiment, the ion beam source generates an inert gas ion beam. In one embodiment, the ion beam source generates a neon ion beam. The above-described ion beam has been proven to be particularly suitable for the detection system.

[0015] In one embodiment, the secondary ion detection device includes a secondary ion transfer unit that is capable of moving between: a first transfer position, where the transfer unit transfers secondary ions emitted from a target volume of a probe structure to be characterized to the secondary ion detection unit; and a second neutral position. The secondary ion transfer unit described above enables switching between a semiconductor structure production mode of a device that can be used as a projection exposure device and a detection mode in which the additional secondary ion transfer unit is in the transfer position. This allows in-line detection during semiconductor production processing.

[0016] In one embodiment, the secondary ion detection unit includes a total ion counter. The total ion counter described above provides ratio information, for example, regarding the occurrence distribution of different elements in a sampling area.

[0017] In one embodiment, the secondary ion detection unit includes an extended detector array for mass filtering signals. The extended detector array described above imparts high spatial resolution to the secondary ion detection device, which can result in high mass resolution. The detector array can be implemented as an array of channel electron multipliers (CEM) or a micro-channel plate (MCP).

[0018] A further object of the present invention is to improve a detection method for characterizing a semiconductor structure, in particular for characterizing a 2D or 3D semiconductor structure.

[0019] This object is achieved by a detection method according to the steps described below. A detection method for characterizing a semiconductor structure includes the following steps: initially examining the structure to be characterized; performing a detailed examination of candidate volumes of interest identified in the initial examination step by: spatially resolved ion beam sputtering in the volume to be examined in detail; detecting secondary ions from the volume to be examined in detail; performing sequential mass spectrometry of the detected secondary ions; where the sequential mass spectrometry is performed simultaneously within an ion mass-to-charge ratio bandwidth.

[0020] It has been recognized that the combination of the original inspection of the structure to be determined on the one hand and the detailed inspection of identifying candidate qualification volumes in the original inspection step using an ion beam and a secondary ion detection device enables the detection of a sample region / volume to be inspected in detail with high accuracy and high information value. The original inspection step can be used to select the volume to be inspected in detail, and this step can be performed by means of a secondary electron microscope image. Then, based on the original information obtained from the original inspection, a detailed inspection based on an ion beam and a secondary ion detection device can be performed. Performing continuous mass spectrometry can collect detailed elemental distribution information of the volume to be inspected in the detailed inspection step. Using this detection method, the quality of the semiconductor structure to be determined can be evaluated using, on the one hand, the results of the original inspection of the structure to be determined and, on the other hand, the results of the detailed inspection of the qualified volume candidates identified within the original inspection step.

[0021] In one embodiment, the lateral spatial resolution during the detailed inspection is better than 100 nm. The above-mentioned lateral spatial resolution provides high information value. Minute structural details corresponding to the resolution of semiconductor structure processing can be inspected in detail.

[0022] In one embodiment, the ion beam is focused on the volume to be inspected in detail with a focal diameter of less than 5 nm. The above-mentioned focal diameter has corresponding advantages.

[0023] In one embodiment, this detection is performed online during semiconductor production. When this detection method is performed online during the semiconductor production process described above, the advantages of this detection method are very effective. Additionally or alternatively, this detection method can be used to perform failure analysis through an object or sample surface and / or for performing defect detection. Such failure analysis / defect detection can be carried out in an offline mode, that is, not during the semiconductor production process.

[0024] The advantages of the detection method according to the following have been discussed above. In one detection method, at least one volume to be inspected in detail is selected by means of a secondary electron microscope image.

[0025] In one embodiment, the material distribution revealed by the continuous mass spectrometry of the detected secondary ions is imaged by secondary electron microscopy. The above-mentioned microscopy imaging allows the material distribution to be depicted as part of this detection method, and different materials contributing to this distribution can be further deduced from the continuous mass spectrometry. Then, this electron microscopy imaging allows the visualization of the various material distributions identified by the continuous mass spectrometry. Description of the Drawings

[0026] Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings. In these figures:

[0027] Figure 1Schematic illustration of electron beam / particle interaction in a detection system for determining a 3D semiconductor structure;

[0028] Figure 2 Further schematic illustration of the main components of the detection system;

[0029] Figure 3 Part of a microscope image obtained by the detection system of secondary electrons generated by the detection system;

[0030] Figure 4 For the mass spectrometer of the detection system at Figure 3 Time-resolved count rate graphs of three different ion energies measured at three different positions within the object part shown inside;

[0031] Figure 5 For comparison with Figure 3 At a further magnified scale, another cross-section of the object imaged by secondary electrons by the detection system before the object milling step using the ion beam;

[0032] Figure 6 For according to Figure 5 Cross-section after the milling step showing three different milled rectangular cross-sections;

[0033] Figure 7 For Figure 6 Cross-section of, where the milled area is highlighted;

[0034] Figure 8 Is a time-resolved graph equivalent to Figure 4 For the time evaluation of three different measured ion energies obtained from the first region highlighted in Figure 7 ;

[0035] Figure 9 Is a time-resolved graph equivalent to Figure 4 For the time evaluation of three different measured ion energies obtained from the second region highlighted in Figure 7 ; and

[0036] Figure 10 Is a time-resolved graph equivalent to Figure 4 For the time evaluation of three different measured ion energies obtained from the third region highlighted in Figure 7 ; Detailed implementation mode

[0037] Figure 1 And Figure 2 Show the working principle and main components of the detection system 1 for determining a three-dimensional (3D) semiconductor structure, especially for determining a lithographic photomask. Such a photomask is particularly suitable for EUV projection lithography.

[0038] The detection system 1 has an ion beam source 2, as schematically shown in Figure 1 . Such an ion beam source 2 is a plasma source with a well-defined source volume. Examples of such ion beam sources are disclosed in US 2007 / 0221843 A1. The ions generated by the ion beam source are inert gas ions, in particular helium ions or neon ions. By providing a corresponding ion beam source, other inert gases can also be used, including argon, krypton or xenon.

[0039] The ion beam source generates an ion beam 3 with well-defined pointing characteristics. The spatial resolution obtained by such an ion beam 3 is better than 20 nm. The ion beam 3 is focused on the object field 4 of the object surface 5, or on a sample 6 with a 3D structure to be determined by the detection system 1. The focal diameter of the ion beam 3 is less than 0.5 nm.

[0040] The ion beam can have an energy ranging from 2.5 keV to 30 keV, for example 25 keV. The beam current of the ion beam can be in the range of 1 to 100 pA, in particular in the range of 10 pA.

[0041] Figure 1 Schematically shows the interaction of the focused ion beam 3 in the object field 4 with the material of the object 6, showing three atoms 7, 8, 9 sputtered by the ion beam 3 from the object field of the surface 5. Atom 7 is positively charged. Atom 8 is neutral. Atom 9 is negatively charged. Also shown are several secondary electrons (SE) generated during sputtering, and are denoted by e- in Figure 1 . Figure 1 Further shows the electron beam interaction region 10 in, where the interaction between the ion beam 3 and the material of the object 6 occurs during sputtering.

[0042] Figure 1 Further shows a Cartesian x / y / z coordinate system in. The coordinates x and y span the surface 5 of the object 6. The coordinate z is perpendicular to this x / y surface plane.

[0043] Such a beam interaction region 10 is a very well-defined volume, whose x / y dimensions are in the range of 5 nm to 50 nm, and the z dimension is in the range of 5 nm and 50 nm. The detection system 1 includes secondary electron optics 11, which can generate a secondary electron image of the object field 4. Such secondary electron optics are also disclosed in US2007 / 0221843 A1. The system 1 can also have projection optics of a projection exposure device for EUV lithography. During such a semiconductor manufacturing process, a three-dimensional structure can be generated by using the projection exposure device of the projection optics and imaging a mask master on the object field 4.

[0044] The detection system 1 further includes a secondary ion detection device 12 for detecting secondary ions, in particular the charged atoms 7 and 9 generated by ion beam sputtering. The secondary ion detection unit 12 includes a mass spectrometer 13. The mass spectrometer 13 is capable of performing secondary ion mass spectrometry (SIMS). Such a mass spectrometer 13 is capable of measuring and in particular continuously measuring the ion mass-to-charge ratio of secondary ions in a given bandwidth. This is shown schematically in Figure 2 which depicts the secondary ion beam paths 14, 15, 16, 17 corresponding to different ion mass-to-charge ratios. After the secondary ions are collected by the extraction optical device, the secondary ions are uniformly accelerated towards the sector magnetic field at, for example, 3 kV.

[0045] The beam path 14 relates to the smallest detectable ion mass. The beam path 17 relates to the largest detectable ion mass. Between this minimum and maximum ion mass, there is a continuous ion mass bandwidth 18 that can be detected by the mass spectrometer 13.

[0046] Figure 2 Shown schematically in is a graph that shows the cumulative count results within the ion mass-to-charge bandwidth 18 after a specific measurement period of the detection system 1. Shown are the cumulative count rates for many different ion mass-to-charge ratios corresponding to the respective different elements. For measuring the ion energy, the mass spectrometer 13 includes a secondary ion detection unit 19 containing a total ion counter. The secondary ion detection unit 19 is implemented as an extended detector array. An example of such a detector array is a channel electron multiplier (CEM) array. The secondary ion detection unit may include 4 or more such channel electron multipliers, such as 4, 5, 6, 8, 10, 15, 20, 25, 30, 50, 75, 100 or even more channel electron multipliers. The secondary ion detection unit 19 may be implemented as a microchannel plate (MCP) having more than 50, more than 100, more than 200, more than 500, more than 1000, more than 2000 or even more than 4000 channels.

[0047] The secondary ion detection unit further includes a secondary ion transfer unit 20. Such a secondary ion transfer unit 20 can move between Figure 2 the first position shown and a second neutral position. In the first position, the secondary ion transfer unit 20 transfers secondary ions (i.e., the charged atoms 7, 9) emitted from the beam interaction region (i.e., from the target volume of the probe structure to be determined) to the mass spectrometer 13, and in particular to the secondary ion detection unit 19; in the second neutral position, the secondary ion transfer unit 20 does not cancel the secondary electrons and / or secondary ions generated within the beam interaction region. To achieve this mobility of the secondary ion transfer unit 20 between the first transfer position and the second neutral position, the secondary ion transfer unit 20 interacts with a drive 21.

[0048] The secondary ion transfer unit 20 includes a first deflection device 22 which is directly located above the beam interaction region 10 in the transfer position of the secondary ion transfer unit 20. The deflection device 22 includes a channel for allowing the ion beam 3 to pass through within the beam path between the ion beam source 2 and the beam interaction region 10. In addition, the secondary ion transfer unit 20 includes a beam tube 23 for encapsulating the secondary ion beam path between the deflection device 22 and the mass spectrometer 13. The mass spectrometer 13 itself includes two additional deflection devices 24, 25 which act as sector magnetic fields to spread the secondary ion beam paths 14 to 17 onto the secondary ion detection unit 19. The secondary ion detection unit 19, i.e., the CEM, is arranged in the focal plane of the sector magnetic field 25. The CEM is used to directly measure secondary ions having different trajectories according to their mass-to-charge ratios (compare Figure 2 the electron beam paths 14 to 17 in

[0049] The deflection device 22 is implemented as a sector electrostatic field.

[0050] The deflection device 24 is implemented as a sector electrostatic field.

[0051] Secondary ions are collected from the sample 6 and electrostatically focused, accelerated and projected onto the focal plane of the secondary ion detection unit 19. The mass spectrometer 13 can have a Mattauch-Herzog design.

[0052] In a typical operating mode of the system 1, the magnetic field of the sector magnetic field 25 and the position of the secondary ion detection unit 19 are kept constant, and during buffering of the sample 6 to obtain information about the sample volume, the count rates on the individual channels of the secondary ion detection unit 19 are measured.

[0053] The mass resolution of the mass spectrometer 13 is sufficient not only to distinguish different elements but also to distinguish individual isotopes.

[0054] By scanning the magnetic field of the sector magnetic field 25 and / or by moving the individual detectors or the entire secondary ion detection unit 19, measurements of the ion mass-to-charge ratio bandwidth can be generated in an alternative operating mode.

[0055] An embodiment, in particular an embodiment of the deflection devices 24, 25 and the secondary ion transfer unit, is disclosed in G. Hlawacek and A. (eds.) "Helium Ion Microscopy, Nanosciences and Technologies" published by Springer International Publishing Switzerland in 2016 (G. Hlawacek and A. (eds.), Helium Ion Microscopy, Nanoscience and Technology, Springer International Publishing, Switzerland, 2016), in particular, is disclosed in Chapter 13 of "SIMS on the helium ion microscope: The powerful tool for high-resolution high-sensitivity Nano-analytics" co-authored by Tom Wirtz et al.

[0056] Using the detection system 1, the following reference Figures 3 to 10 Describes a detection method for determining a 3D semiconductor structure.

[0057] The detection method includes a step of performing an initial review of the structure to be determined.

[0058] Figure 3 An example of this initial review detection step is shown. What is shown is a portion of the object 6 to be determined. This sample region 26 of the object 6 is generated by conventional secondary electron microscopy techniques of the secondary electron optical device 11 using the detection system 1. The object 6 to be detected includes many structural regions. Figure 3 Sub-regions "1", "2", and "3" of these object structures to be further detected are highlighted.

[0059] Sub-region "1" includes a ridge structure that shows a certain plug in electron microscope imaging without further definition. Sub-region "2" shows a corresponding ridge without such a plug. Sub-region "3" is an example of multiple "outgrowth" structures at many positions on the sample region present in the object 6 during the initial review step.

[0060] These highlighted sub-regions "1", "2", and "3" serve as qualification volume candidates, which are identified in the initial review step. During this detection method, at this time, these sub-regions "1", "2", and "3" further undergo a detailed review during this detection method. During this detailed review, by directing the ion beam 3 at these sub-regions "1", "2", and "3", spatially resolved ion beam sputtering is performed in the volumes of the corresponding sub-regions "1", "2", and "3". For each of these sub-regions "1", "2", and "3", secondary ions are detected in a time-resolved measurement during the detailed review (compare Figure 1secondary ions 7 and 9). These detected secondary ions are subjected to continuous mass spectrometry using a secondary ion transfer unit and a mass spectrometer 13, i.e., using the secondary ion detection device 12 of the detection system 1 as described above with reference to Figure 2 the secondary ion detection device 12 of the detection system 1 described above.

[0061] Figure 4 Displays the time-resolved results of a detailed review of sub-regions "1", "2", and "3". Figure 4 The ordinate in is the measured count rate in counts per second (CPS).

[0062] During the measurement, the ion beam 3 in the first period T1 is directed to sub-region "1", in the subsequent period T2 to sub-region "2", and in the third and final period T3 to sub-region "3".

[0063] As shown by the solid line, the count rate at the first ion energy level corresponding to silicon (Si) in the mass spectrometer 13 is given. As shown by the dashed line, the count rate corresponding to the ion energy of titanium (Ti) is given. As shown by the dotted-dashed line, the count rate corresponding to the ion energy of copper (Cu) is given.

[0064] According to Figure 4 the time-resolved counts, further information on the depth distribution of the occurrence of the elements Si, Ti, and Cu is given. In sub-region "1", titanium and copper are present on the surface. When the ion beam 3 mills below the surface of sub-region "1", after a short sampling time, the amounts of titanium and copper decrease and the amount of the base material silicon increases and dominates.

[0065] In sub-region "2", titanium is not present, and the time-resolved behavior of the count rates related to silicon and copper is similar to the measurement behavior of sub-region "1". By comparing the measurement results of sub-regions "1" and "2", it can be inferred that Figure 3 the plug shown in the secondary electron micrograph of

[0066] The measurement at the "outward growth" position in sub-region "3" reveals that there appears to be a titanium trace just above the resolution limit of the mass spectrometer 13. The time-resolved behavior of the presence of silicon and copper is similar to that in sub-regions "1" and "2". From the comparison of the count rate measurements in sub-region "3" with those in sub-regions "1" and "2", it can be concluded that Figure 3 the "outward growth" shown in the secondary electron microscope image of

[0067] The lateral spatial resolution regarding the above detailed inspection steps is better than 100 nm, particularly better than 75 nm, better than 50 nm, and better than 30 nm. The lateral spatial resolution, that is, the resolution in x and y, can be 20 nm or even better. The depth resolution (in the z direction) depends on the milling rate of the ion beam 3 in the material of the object 6. This depth resolution can also be in the range of 100 nm or even better.

[0068] The accuracy regarding the surface area detected by the ion beam 3 in the object field 4 can be better than 5 nm, can be better than 3 nm, and even can be better than 1 nm. This accuracy is decisive especially when attempting to capture the probe structure (such as "outward growth" in sub-region "3"). Such more or less punctiform sub-regions are detected through the original inspection, and then their coordinates are sent to the relative positioning control of the detection system 1 to ensure that the electron beam interaction region 10 is correctly positioned on the sub-region under discussion, such as sub-region "3". For this purpose, the object 6 is located at a high-precision xyz coordinate table, which has corresponding drives to move the object 6 in a clearly defined manner relative to these Cartesian coordinates x, y, z.

[0069] In addition or alternatively, this relative movement between the ion beam 3 on the one hand and the object 6 on the other hand can be achieved through a scanning scheme used to scan the ion beam 3, for example, through at least one, especially two scanning coils.

[0070] The xy extension of the beam interaction region 10, that is, the diameter of the ion focus on the object field 4, can be less than 1 nm, especially less than 0.5 nm.

[0071] The beam current can be less than 20 pA and can be less than 9 pA. This small beam current can enable a very high spatial resolution for the detailed inspection.

[0072] Figure 5 and Figure 6 shown at an enlarged spatial resolution before the milling step ( Figure 5 ), that is, before the ion beam 3 interacts with the object 6, and after such a milling step ( Figure 6 ), the anvil-like structure of the object 6.

[0073] Figure 6 The milling shown in the three linear sub-regions "1", "2", and "3" has a longitudinal extension of approximately 3 μm and a lateral extension of approximately 200 nm.

[0074] Figure 7 Shown again is the now highlighted Figure 6 milled sub-regions "1", "2", and "3".

[0075] Figures 8 to 10 Similar to Figure 4The diagram shows, during the detailed review qualification volume candidate, i.e., during the original review step, i.e., Figure 5 During the electron microscopy imaging of, the identified sub-regions "1", "2", and "3" correspond to the count rates of the ion energies of the elements selenium (Se), tellurium (Te), and antimony (Sb) measured by the secondary ion detection device 12 in the detection system 1.

[0076] Figure 8 The time-resolved count rate of sub-region "1" is shown. This CPS result shows a relatively high selenium content, accompanied by low contents approaching the resolution limit of tellurium and antimony.

[0077] Figure 9 The result of sub-region "2" is shown, where the contents of all three elements selenium, tellurium, and antimony are low. According to Figure 9 , the contribution of selenium in the CPS measurement starts to occur at a longer milling time in sub-region "2" indicated by the ion beam 3. Selenium is not directly present on the surface but below the surface.

[0078] Figure 10 The time-resolved count rate measured within sub-region "3" is shown. Selenium and tellurium are present near the resolution limit. No trace of antimony is found within sub-region "3".

[0079] As described above, especially regarding Figures 3 to 10 The detection method described can be performed online during the production of the semiconductor structure of the object 6. In DE 10 2016 201 317 A1 and DE 10 2017 210 162 A1 and the references cited therein, examples of projection lithography exposure methods for manufacturing semiconductor structures at the micron or nanoscale are given. After the trimming step, the corresponding three-dimensional structure generated in the object field 4 of the projection exposure device appears, and then can be reviewed online (in-situ) by the above detection system 1. Production errors, especially system production errors, can be detected during the process. Therefore, they can be offset to reduce such manufacturing errors during the production process, thereby reducing waste.

Claims

1. A detection system (1) for determining a semiconductor structure, - having an ion beam source (2) for spatially resolved imaging of the structure to be determined with an ion beam (3); - having a secondary ion detection device (12); - wherein the secondary ion detection device (12) includes a mass spectrometer (13); - wherein the mass spectrometer (13) is capable of simultaneously measuring the ion mass-to-charge ratio within a given bandwidth; and - wherein the secondary ion detection device (12) includes a secondary ion detection unit (19) and a secondary ion transfer unit (20), and the secondary ion transfer unit is capable of moving between: - a first transfer position, in which the secondary ion transfer unit (20) transfers secondary ions (7, 9) emitted from a target volume of the probe structure to be determined to the secondary ion detection unit (19); and - a second neutral position, in which the secondary ion transfer unit (20) does not counteract secondary electrons and / or secondary ions generated within the beam interaction region.

2. The detection system according to claim 1, wherein the mass spectrometer (13) is capable of continuously measuring the ion mass-to-charge ratio within the given bandwidth.

3. The detection system according to claim 1 or 2, wherein the ion beam source (2) generates an inert gas ion beam (3).

4. The detection system according to claim 3, wherein the ion beam source (2) generates a neon ion beam.

5. The detection system according to claim 1 or 2, wherein the secondary ion detection unit (19) includes a total ion counter.

6. The detection system according to claim 1 or 2, wherein the secondary ion detection unit (19) includes an extended detector array for mass filtering signals.

7. A detection method for determining a semiconductor structure, comprising the steps of: - initially examining the structure to be determined; - performing a detailed examination of the candidate qualification volumes identified in the initial examination step by: -- spatially resolved ion beam sputtering in the volume to be examined in detail; -- detecting secondary ions (7, 9) from the volume to be examined in detail; -- performing a continuous mass spectrometry analysis of the detected secondary ions; -- wherein the continuous mass spectrometry analysis is performed simultaneously within an ion mass-to-charge ratio bandwidth, - wherein the detection is performed online during semiconductor production.

8. The detection method according to claim 7, wherein the lateral spatial resolution during the detailed examination is less than 100 nm.

9. The detection method according to claim 7 or 8, wherein the ion beam is focused on the volume to be examined in detail with a focal diameter of less than 5 nm.

10. The detection method according to claim 7 or 8, wherein at least one volume to be examined in detail is selected by a secondary electron microscope image.

11. The detection method according to claim 7 or 8, wherein the material distribution revealed by the continuous mass spectrometry analysis of the detected secondary ions is imaged by a secondary electron microscope.

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