TW202326789A - Method and apparatus for determining a beam tail of a focused particle beam - Google Patents

Abstract

The present invention relates to a method (1800) and an apparatus (1700) for determining an intensity distribution of at least one beam tail (120, 125, 130, 135) of a focused particle beam (100). The method (1800) comprises the steps of: (a) irradiating (1820) a test element (300, 500, 1100, 1400, 1600) with the focused particle beam (100) such that the at least one beam tail (120, 125, 130, 135) of the focused particle beam (100) causes at least one measurable change (620, 955, 1250, 1540, 1670) of the test element (300, 500, 1100, 1400, 1600); and (b) measuring (1830) the at least one change (620, 955, 1250, 1540, 1670) of the test element (300, 500, 1100, 1400, 1600) for the purposes of determining the intensity distribution of the at least one beam tail (120, 125, 130, 135) of the focused particle beam (100).

Description

Method and apparatus for determining the beam tail of a focused particle beam

The present invention relates to methods and apparatus for determining the beam tail of a focused particle beam. In particular, the invention relates to methods and apparatus for determining the intensity distribution of the tail of a focused particle beam, such as an electron beam. [Cross-reference]

The present application claims German Patent Application No. DE 10 2021 210 005.8 filed with the German Patent and Trademark Office on September 10, 2021, entitled "Method and device for determining the beam tail of a focused particle beam (Verfahren und Vorrichtung zum Bestimmen eines Strahlausläufers eines fokussierten Teilchenstrahls), which is hereby incorporated by reference into this application in its entirety.

Advances in nanotechnology allow the production of components with smaller and smaller structural elements whose dimensions reach the nanometer scale. In order to visualize nanostructures, measurement tools that can image these structures are needed to produce realistic images of these structures from their measurement data.

Microscopy is a powerful tool for imaging nanostructures. In a microscope, a particle beam typically interacts with the sample to be analyzed or processed. Microscopes can be divided into two categories, optical or light microscopes use photons to image a sample. This microscope type images microscopic structures in a number of different ways. Except for certain types, the resolution of an optical microscope is limited by the wavelength of the light source used to expose the sample to be examined, and by the numerical aperture of the optics used to image the sample due to diffraction effects. The production of light sources in the deep ultraviolet (DUV) wavelength range, especially for shorter wavelengths such as in the extreme ultraviolet (EUV) wavelength range, is complex.

Due to the short de Broglie wavelength of electrons used for imaging purposes, microscopes that use large numbers of particles to image nanostructures, such as electron microscopes, have significant advantages over optical microscopes in terms of resolution. For example, as is the case with light microscopy, the diffraction limit of electron microscopy is linearly proportional to the de Broglie wavelength of the electrons and inversely proportional to the aperture angle of the electron beam used. Therefore, the diffraction limit of the electron beam can be reduced by accelerating the electrons of the electron beam to a greater kinetic energy.

Due to the high resolution and its ability to locally initiate chemical reactions, focused particle beams are also used to repair localized defects in nanostructures. For example, defective nanostructures may appear on wafers, photo-etching masks, and/or stamps used in nanoimprint lithography. The defective nanostructures are also often repaired by local particle beam induced etching processes and/or deposition processes. Due to the aberrations of the beam shaping system that shapes the focused particle beam, the focused particle beam typically has a beam tail that extends well beyond the region of an ideal Gaussian focused particle beam. However, only the central part of the Gaussian distribution of the focused particle beam is considered in conventional resolution measurements.

However, particles incident on the sample in one or more beam tails, and thus incident far away from the location to be treated, are also important for localized particle beam induced repair treatments. First, particles in one or more beam tails reduce the number of particles available in the region of the sample to be treated; second, particles in the beam tails may cause unintended particle beam-induced etching and/or deposition outside of the region of the sample to be repaired Process. For example, the quality of the beam profile affects the number of repetitions of the restoration process required for the best possible restoration.

F. Stumpf et al. in the literature "Detailed characterization of lateral damage to silicon carbide samples induced by focused ion beams by electronic scanning probe microscopy and transmission electron microscopy ( J. of Appl. Physics 123, 125104- 1 to 125104-10 (2018))" proposed a study on the lateral damage caused by focused ion beams on silicon carbide. The damage was characterized using scanning probe microscopy (SPM) (ie, scanning diffusion resistance microscopy) and conduction atomic force microscopy (c-AFM).

Therefore, in order to assess the quality of the nanostructure imaging process, and in particular the quality of the nanostructure repair process, it is important to know the intensity profile of the beam tail of the focused particle beam in addition to the profile in the central region. Current methods for determining the beam profile of a focused particle beam generally have only very low sensitivity in determining the intensity distribution of the beam tail of the focused particle beam. An example of this is the complex preparation of samples (thin sections) for analysis by transmission electron microscopy (TEM). In particular, it is currently difficult to quantitatively analyze the intensity distribution of the beam tail of a focused particle beam.

The invention thus solves the problem of specifying a method and a device allowing determination of the intensity distribution of the beam tail of a focused particle beam.

According to an example embodiment of the present invention, this problem is at least partly solved by the subject matter defined in the independent claims; in the dependent claims a number of example embodiments are described.

In one embodiment, a method for determining an intensity distribution of a particle beam on a sample comprises the steps of: (a) irradiating a test element with the particle beam such that the particle beam causes at least one measurable change in the test element and (b) measuring the at least one change of the test element to determine an intensity distribution of the particle beam on the sample.

The method of the present invention converts or converts the intensity distribution of the particle beam into a permanent or continuous change in the test element. The test element can be adapted to the intensity distribution of a particular particle beam. For example, a particle beam may irradiate available precursor gases on the test element to cause the at least one measurable change. In another example, a single layer of a test element can image the intensity distribution of a particle beam in continuous variation in its structure. Permanent changes of the test element can be detected and the intensity distribution of the particle beam can be derived from the measured change of the test element. The intensity distribution may be related to various error sources that may cause the intensity distribution to deviate from the ideal expected intensity distribution. Thus, various sources of influence can be identified, and then the influence of one or more sources can be systematically reduced or even nearly eliminated.

The particle beam may be a focused particle beam, and determining the intensity distribution may include determining the focused particle beam by irradiating the test element with the focused particle beam such that at least one tail of the focused particle beam causes at least one measurable change in the test element and measuring the at least one change in the test element to determine the intensity distribution of the at least one tail of the focused particle beam.

An ideal Gaussian beam can be easily divided into a main or central beam, and a beam tail. Starting from the intensity maximum _I0 , the main beam can be defined as the region of intensity greater than a critical value associated with the intensity maximum. For example, the critical value can be defined as I > I ₀ ·e ⁻² . The beam tail is formed by a region whose intensity is less than a specified relative critical value, eg I<I ₀ ·e ⁻² .

The beam profile described in this application may deviate significantly from the ideal Gaussian intensity distribution; however, in this application the main or central beam is defined to resemble an ideal Gaussian beam, which means The intensity maximum _I0 of the beam is determined in a first step. A certain percentage drop off from the maximum value is then designated as the critical value, which marks the boundary between the center beam and the beam tail. For a real particle beam, one or more beam tails are formed by the entire intensity directed outside the central beam. This definition does not imply that the intensity must remain below a certain critical value at every point of the beam tail, but that the intensity can grow again with increasing distance from the intensity maximum. Furthermore, in contrast to an ideal Gaussian beam, a real beam may have a beam tail whose intensity profile does not extend rotationally symmetrically around the intensity maximum _I0 . In the following, this case is characterized by two or more bundle tails. Preferably, these definitions (main beam and beam tail) relate to the focal point or the region near the focal point in which the beam waist of the focused particle beam does not increase by more than a factor of 2 relative to the diameter of the focal spot (a factor of 2).

The method facilitates quantitative analysis of the beam tail of a focused particle beam by interacting with a test element to make visible the effects of particles contained in the beam tail. This detection process can be performed in such a way that the particles of the main beam of the focused particle beam have substantially no influence on the variation of the test element. In other words, the variation of the test element is essentially only determined by the beam tail(s).

The intensity distribution of the beam tail of the focused particle beam can be quantitatively determined from visible or measurable changes in the test element. Knowledge of the intensity distribution over the entire area illuminated by the focused particle beam can be used to optimize the images produced by scanning the sample with the focused particle beam. Furthermore, knowledge about the intensity of the focused particle beam present in the beam tail can be used to optimize local particle beam induced processing of the sample. For example, knowledge of the intensity distribution of the beam tail of a focused particle beam may allow minimizing the number of cycle iterations required for the best possible repair of a defect.

The particles of the particle beam may be particles with no rest mass, such as photons; in this case, the intensity of the particle beam is directly proportional to the electrical energy density distribution. However, the particles of the particle beam may also be particles with mass, such as electrons, atoms, ions or molecules; in these cases the intensity is proportional to the absolute value squared of the amplitude of the wave function of the corresponding particle type.

The particle beam can irradiate the sample through at least one precursor gas, and determining the intensity distribution can include determining a change in the intensity distribution caused by the at least one precursor gas. The at least one precursor gas can be located on the sample.

As the particle beam passes through the precursor gas, the particles of the precursor gas may scatter the particles of the particle beam. Scattering of beam particles often leads to unwanted beam expansion on the sample. For example, a focused particle beam with a focal spot of about 10 nm can be extended to the millimeter range. The amount of scattering depends on the concentration or density of the precursor gas.

Furthermore, the fraction of scattered beam particles depends on the path length along which the particle beam propagates within the precursor gas. In addition, the scattering effect of the precursor gas can be reduced by increasing the kinetic energy of the beam particles. However, the high kinetic energy of the beam particles is generally undesirable because it increases the interaction volume of the particle beam with the sample. In general, the optimum kinetic energy of beam particles is in the range between very low and high kinetic energy. Furthermore, it is beneficial to minimize the volume of precursor gas that the beam must pass through. In addition, reducing the precursor gas density can also help minimize beam expansion of the particle beam. On the other hand, precursor gases are required to initiate and sustain local particle beam-induced chemical reactions.

Determining changes in the intensity distribution can help optimize particle beam and/or precursor gas induced etch and/or deposition processes. It can help to fully characterize possible deviations between an applied process and an ideal expected process. This variation can be determined for different pressures and/or flow rates of precursor gases.

The particle beam can illuminate the sample through a shielding element, and determining the intensity distribution can include determining a change in the intensity distribution across the sample caused by the shielding element.

Shielding elements can be used to shield the charged particle beam from electrostatic charges that develop on the sample surface due to the interaction of the charged particle beam with the sample. Residual gas particles and/or precursor gas particles can scatter beam particles on their way from the particle source to the sample. A shielding element arranged in the beam path at a small distance above the sample may also act as a barrier or aperture to scatter beam particles.

Determining the effect of shielding elements on the intensity distribution may also assist in optimizing particle beam and/or precursor gas induced etch and/or deposition processes. This allows for a complete characterization of possible deviations of an applied process from an ideal expected process. For example, (a change in) the intensity distribution may be derived from at least one change in the test element by correlating with the pattern of the shielding element.

The shielding element may at least one of redistribute scattered particles passing through the shielding element in the direction of the beam, and generate secondary particles (eg, secondary electrons).

The result is a redistribution of scattered particles by the shielding element, and its effect as a source of secondary particles, eg, enhanced particle-inducing treatment on the sample surface outside the intended area defined by the particle beam's spot size. Thus, the application of shielding elements can amplify unwanted treatment of the sample surface.

In a further embodiment, a method for determining a spontaneous etch rate and/or a spontaneous deposition of at least one precursor gas used in a particle beam induced etching process and/or in a particle beam induced deposition process of a sample The rate method comprises the steps of: (a) providing the at least one precursor gas to a test element at a predetermined gas flow rate for a predetermined period of time without irradiating the test element with a particle beam; and (b ) measuring the at least one change of the test element to determine the spontaneous etch rate and/or the spontaneous deposition rate of the at least one precursor gas on the sample.

In the case of localized particle beam induced chemical processing, spontaneously induced processing by precursor gases is generally very undesirable because it reduces process control. Spontaneous etching of the precursor gas used as the etching gas inadvertently removes material from the sample. In addition, spontaneous deposition of precursor gases used as deposition gases can accidentally deposit material on the sample. Furthermore, spontaneously deposited material may not have the expected material composition.

Spontaneous processing typically acts on larger sample areas because lateral control of the concentration of precursor gases on the sample is difficult. In general, spontaneous processing results in small sample variations of only a few nanometers, but even these small variations can be detrimental for certain types of samples, such as optical masking. Furthermore, the resulting variation may vary over a larger area, ie over an area of one or several square millimeters. The application of specially designed test elements may allow the measurement of this small variation of the sample and its variation throughout the sample, e.g. caused by precursor gas concentration spikes and the like. For example, a local spike can cause a local peak in the variation of the test element.

Spontaneous processing can account for effects on the sample that are not caused by the particle beam when performing a localized particle beam induced chemical process, but by the precursor gases used in the localized particle beam induced process. The study of these treatments enables the separation of the effect of the beam tail from the effect of the applied precursor gas, and thus allows a comprehensive study of the intensity distribution of the beam and the lateral resolution of the precursor gas in the local beam-induced chemical reaction These two effects of the spontaneous variation caused by the degree to the sample. Analysis of these two effects could improve the control of local particle beam-induced chemical reactions.

In some examples, the gas flow rate may not be predetermined, but other quantities may be controlled to obtain a controllable precursor gas environment, such as pressure, density, temperature, and the like.

In another example, a method for determining residual changes in a sample includes the steps of: (a) providing at least one precursor gas at a predetermined gas flow rate on a test element for a predetermined period of time without a particle beam irradiating the test sample; (b) measuring at least one change in the test element to determine a spontaneous etch rate and/or a spontaneous deposition rate of the at least one precursor gas on the sample.

Determining the spontaneous etch rate, and/or the spontaneous deposition rate may further comprise changing at least one of: the gas flow rate, the composition of the at least one precursor gas, and the temperature of the at least one precursor gas, and providing At least one precursor gas having a predetermined gas flow rate for a predetermined period of time without irradiating the test element with the particle beam.

The effect of spontaneous treatments can be studied by performing one or more test treatments. For example, a test element is measured in a first step. The test element is then exposed to the action of the precursor gas under predetermined conditions. Following the instructions, analyze the continuous variation of the test element. Parameters affecting spontaneous processing were varied systematically to determine their effect on spontaneous etch or deposition rates.

A further aspect of the invention, independently related, but also in combination with other concepts herein, is a test element. The test element may comprise a base element and at least one structural element, wherein the at least one structural element may preferably be arranged on the base element.

The at least one structural element of the test element may be specifically designed for use with one of the methods outlined herein. The structural elements used to determine the intensity distribution of the particle beam or parts of the particle beam (eg the beam tail) may differ from one or more structural elements of the test structure used to determine the influence of spontaneous treatment.

The at least one structural element may have a height ranging from 1 nm to 1000 nm, preferably from 5 nm to 500 nm, more preferably from 10 nm to 200 nm, and most preferably from 20 nm to 100 nm.

The at least one structural element may comprise at least 2, preferably at least 5, more preferably at least 10, and most preferably at least 30 parallel line segments with an interval of 50 to 150 nm or 80 to 120 nm, preferably 30 to 70 nm or 40 to 60 nm, more preferably 20 to 40 nm or 25 to 35 nm, and most preferably 5 to 25 nm or 10 to 20 nm.

The structural element may comprise a first material and the base element may comprise a second material, wherein the first material may be different from the second material.

For example, one of the two materials may be unaffected by spontaneous processing and thus serve as a reference, while the other material may be altered by the effect of the precursor gas. Benchmarking of test structures allows precise determination of small variations in test elements. Furthermore, a test element having several specific structural elements enables the determination of small lateral changes in the test element caused by exposure to the precursor gas. Furthermore, by using several specific structural elements, slow structural changes can be detected by discretizing the slow structural changes.

A spontaneous etch rate of the first material induced by the at least one precursor gas differs from a spontaneous etch rate of the second material of the test sample by a factor of at least 2, preferably by a factor of at least 5, more preferably by a factor of at least 10 times, and preferably at least 20 times.

The at least one structural element may have at least one of: a one-dimensional (1-D) structure, a two-dimensional (2-D) structure, and a three-dimensional (3-D) structure.

The at least one structural element includes at least one of: a checkerboard pattern, an aperture mask with at least one opening, at least one pillar, and a randomization structure.

The randomized structure comprises gold particles (eg spherical) on a carbon layer.

Measuring the at least one variation of the test element includes at least one of: measuring an edge variation of the test element, and measuring a region-to-region variation of the test element.

Measuring the at least one variation of the test element may comprise measuring variation of an edge of at least one structural element of the test element, and measuring variation between regions of the test element may comprise measuring variation between regions of the at least one structural element, and/or measure region-to-region variation of the base element of the test element.

Irradiating the test element can cause at least one topographic change, at least one chemical change, and/or at least one physical change of the test element.

The change(s) of the test element are measurable, so the change can be measured. The dose distribution of the particles in the beam and/or the beam tail of the focused particle beam can be deduced from the measured change(s) of the test element, assuming the induced change(s) in the test element are proportional to the local effective intensity.

The test element has at least one test structure, which includes at least one element of the following groups: - At least one height step; - at least one hard mask having at least one opening; and - At least one monolayer.

The at least one step defines an upper plane by the top side of the step and a lower plane by the lower edge of the step. The hard mask designates the top side as the side on which the focused particle beam is incident on the hard mask, and designates the back side opposite the top side. The upper and lower planes of the at least one step height, and the top and back sides of the hard mask may be substantially flat. Furthermore, the upper and lower planes of the at least one step height, and the top and back sides of the hard mask may form substantially parallel planes. The parallelism of the upper and lower planes or the top and back sides of the hard mask can improve the accuracy of determining the intensity distribution of the beam tail of the focused particle beam.

The test structure can include at least one step and a single layer, and/or the test structure can include a hard mask with at least one opening and can include a single layer.

The test element may include a base element. The top side of the base element may form the at least one step-high lower plane. The base element of the test element can be the substrate of the optical mask. The at least one step height can be a pattern element of an optical mask. The base element of the test element may be the base material of the optical mask or the wafer, and one or more steps may be etched into the optical mask or the base material of the wafer, and/or may Wafers are produced by depositing materials on a substrate.

A hard mask can be applied to the top side of the base element of the test element. The at least one opening of the hard mask may expose a portion of the top side of the base element. At least one opening of the hard mask can be created by etching.

A hard mask is a mask that is resistant to prolonged exposure to a focused particle beam, compared to a polymer mask made of photoresist. For example, the hard mask can include a metal layer, an oxide layer, or a nitride layer.

In this specification, the term "substantially" denotes the indication of a measured quantity within a measurement uncertainty when the corresponding quantity is measured using a measuring device according to the prior art.

The at least one step and/or the at least one opening can have at least one edge, and/or the monolayer can be designed to alter secondary electron contrast when irradiated with the focused particle beam.

At least one step and/or at least one edge of at least one opening of the hard mask may be arranged on an upper plane of the at least one step and/or a top side of the hard mask. The at least one edge may comprise a cross-sectional straight edge.

A single layer may be applied to the at least one step, to a hard mask having at least one opening, and/or to a base element of a test element. The intensity distribution of the beam tail of the focused particle beam may be determined from the variation applied to the at least one high-order monolayer and/or from the variation applied to the monolayer in the at least one opening of the hard mask.

The method may further include: setting the height of the at least one step height, and/or the thickness of the hard mask, so that the beam area of the focused particle beam increases by at least 2%, preferably 5%, more preferably 10%, and most preferably 30%.

The beam waist of the focused particle beam may have a diameter < 20 nm, preferably < 10 nm, more preferably < 5 nm, and most preferably < 2 nm.

Below, both the beam waist diameter and the focal spot diameter are related to the intensity drop to e ^-2 , that is, the intensity drops to 13.5% of the maximum intensity. If the main beam of a focused particle beam is based on this definition, then the main beam of an ideal Gaussian beam carries about 93% of the particles, and the beam tail carries about 7%. Aberrations in real particle optics can lead to an increased fraction of particles contained in the beam tail. For example, aberrations may result in beam tails with dimensions in the 100 nm range.

The test element may have N test structures or structural elements, which include 1≤N≤1000, preferably 5≤N≤500, more preferably 10≤N≤100, most preferably 20≤N≤50. A test element with N identical test structures can be used for N calibration measurements of the intensity distribution of the particle beam and/or the beam tail of the focused particle beam. This test element can be installed into the device during its production, which can then be used to analyze the beam, or focus the particle beam after each service, after modification, and/or after the device is serviced during its service life beam tail. In addition, test elements can be used to study the effects of spontaneous handling on samples. However, it is also possible to introduce the test element into the device before analyzing one or more beam tails of the focused particle beam.

For example, a test element can be an integral part of a sample.

The test device may include at least two test structures from the group: at least one step, a hard mask with at least one opening, and a single layer.

Two or three different types of test structures can be combined on one test element. Thus, the accuracy with which the tail(s) of the focused particle beam and/or the intensity distribution of the particle beam can be determined can be optimized. In addition, the test element may also contain one or more test elements with test structures specifically designed to analyze the effect of spontaneous processing on the sample.

Irradiating the test element may include: focusing the particle beam on at least one element of the following group: - an upper plane of the at least one step, and/or a rear side of the hard mask; - a lower plane of the at least one step, and/or a top side of the hard mask; - a top side of the single layer.

Embodiments in which the focused particle beam is focused on at least one higher lower plane and/or the top side of the hard mask are presently preferred. In these embodiments an optimal separation of the beam tail from the central or main part of the focused particle beam can be obtained and thus the dose distribution of the beam tail can be analyzed with minimal influence of the main beam.

In embodiments where the focused particle beam is focused on the upper plane of at least one step and/or the underside of the hard mask, some particles generated by the main beam in the step or hard mask will enter the region of the beam tail, Thus, in addition to changing the intensity distribution of the beam tail, the test structure of the test element is also changed. This makes the analysis of the dose distribution at the beam tail of the focused particle beam more difficult.

Particles generated by the focused particle beam in the test element may contain secondary electrons (SE) and/or backscattered electrons (BSE) from the test element.

In the upper plane or top side of the hard mask, at least one step and/or at least one cross-sectional straight edge of at least one opening of the hard mask may comprise an angle α in the range of 60°<α<120°, It is preferably within the range of 75°<α<105°, more preferably within the range of 85°<α<95°, most preferably within the range of 89°<α<91°.

The at least one height may include at least two heights, which are arranged symmetrically with respect to a line of symmetry, and the line of symmetry may lie in a lower plane. The at least one step preferably comprises at least four steps, the edges of which have substantially an angle of 90° to each other.

The hard mask may include at least two openings, which are symmetrically arranged with respect to the incident point of the focused particle beam on the hard mask, and/or symmetrically arranged with respect to at least one scanning direction of the focused particle beam. The at least one opening of the hard mask preferably has a rectangular shape. Slot-shaped openings of the hard mask, in particular in the form of concentric structures, eg rings, around the point of incidence of the focused particle beam on the hard mask are also advantageous.

With respect to the upper plane of the step or the top side of the hard mask, at least one edge of at least one step and/or at least one edge of at least one opening of the hard mask may comprise an angle β in the range 60°<β<120 °, preferably within the range of 75°<β<105°, more preferably within the range of 85°<β<95°, most preferably within the range of 89°<β<91°.

Having a right angled step between the lower and upper planes, or a right angled hard mask opening between the top side and the back side increases the resolution in determining the beam tail dose distribution of the focused particle beam.

Irradiating the test element may comprise at least one element of the following group: - irradiating at least one point of the lower plane of the at least one step with the focused particle beam such that the at least one beam tail is incident on an upper plane of the at least one step; - scanning the focused particle beam along at least one edge of the at least one step such that the at least one tail of the focused particle beam is incident on the upper plane of the at least one step; - irradiating at least one point of the hard mask with the focused particle beam such that at least a portion of the at least one beam tail is incident on the at least one opening in the hard mask; - scanning the focused particle beam parallel to the at least one edge of the at least one opening in the hard mask such that at least a portion of the at least one beam tail is incident on the at least one opening in the hard mask; - irradiating at least a point of the monolayer.

Irradiating the test element may comprise at least one element of the following group: - selecting a distance between an intensity maximum of the focused particle beam and the at least one edge of the at least one step such that particles generated by the focused particle beam in the lower plane of the at least one step are substantially free of reaching the upper surface of the at least one step; - selecting a distance between the intensity maximum of the focused particle beam and the at least one edge of the at least one opening in the hard mask such that particles produced by the focused particle beam in the hard mask are substantially free of reaches into the at least one opening; - selecting the energy of the focused particle beam such that substantially none of the particles of the focused particle beam reach a rear side of the monolayer.

The main part of the focused particle beam can generate secondary particles such as SE and/or BSE in the lower plane of the test element or in the substrate element. These particles should not reach this at least first-order high upper plane, otherwise they could mix with particles of the beam tail or secondary particles generated with the beam tail and thus cover the detection of changes in the test element caused by the beam tail. The same applies to particle beams incident on hard masks. By spatially separating the influence of the main beam and the influence of the beam tail, the dose distribution at the beam tail can be analyzed substantially independent of interference from the main beam of the focused particle beam.

When irradiating a monolayer with a focused particle beam, the kinetic energy of the particles can be set such that these particles are virtually unable to penetrate the test element to which the monolayer has already been applied, so that the secondary particles generated in the test element cannot alter the chemical composition and /or structure.

Irradiating the test element may comprise scanning the focused particle beam along at least one edge of the at least two-step height in at least two different distances between an intensity maximum of the focused particle beam and at least one edge of the at least two-step height.

By varying the distance between the intensity maximum of the focused particle beam and the edges of the plurality of steps, the best possible positioning of the focused particle beam for scanning along the edges of the first steps can be determined. This minimizes the influence of the main beam on the analysis of one or more beam tails.

Irradiating the test element may comprise: providing at least one precursor gas comprising at least one of: providing the at least one precursor gas in the region of the particle beam and providing at least one in the region of at least one tail of the at least one focused particle beam a precursor gas. Test elements undergo layout changes by performing localized particle beam-induced chemical reactions. The spatial separation of the main beam and the beam tail of the focused particle beam makes the intensity distribution of the beam tail visible (ie measurable), independent of interference from the main beam.

The at least one precursor gas may include at least one element selected from the group consisting of at least one etching gas, at least one deposition gas, and at least one additive gas.

The at least one deposition gas may comprise at least one element selected from the following group: metal alkyl, transition element alkyl, main group alkyl, metal carbonyl, transition element carbonyl, main group carbonyl, metal alkoxide, transition element alcohol Salts, main group alkoxides, metal complexes, transition element complexes, main group complexes and organic compounds.

Metal alkyl, transition element alkyl and main alkyl group may contain at least one element selected from the group consisting of: cyclopentadienyl (Cp) trimethylplatinum (CpPtMe ₃ ), methylcyclopentadienyl ( MeCp) trimethylplatinum (MeCpPtMe ₃ ), tetramethyltin (SnMe ₄ ), trimethylgallium (GaMe ₃ ), ferrocene (Cp ₂ Fe) and bisaryl chromium (Ar ₂ Cr). Metal carbonyls, carbonyl transition elements and carbonyl main groups may contain at least one element selected from the group consisting of chromium hexacarbonyl (Cr(CO) ₆ ), molybdenum hexacarbonyl (Mo(CO) ₆ ), tungsten hexacarbonyl (W( CO) ₆ ), dicobalt octacarbonyl (Co ₂ (CO) ₈ ), triruthenium dodecacarbonyl (Ru ₃ (CO) ₁₂ ), and iron pentacarbonyl (Fe(CO) ₅ ). Metal alkoxides, transition element alkoxides and main group alkoxides may contain at least one element selected from the group consisting of tetraethyl orthosilicate (TEOS, Si(OC ₂ H ₅ ) ₄ ) and titanium tetraisopropoxide (Ti(OC ₃ H ₇ ) ₄ ). Metal halides, transition element halides and main group halides may contain at least one element selected from the group consisting of: tungsten hexafluoride (WF ₆ ), tungsten hexachloride (WCl ₆ ), titanium tetrachloride (TiCl ₄ ), boron trichloride (BCl ₃ ) and silicon tetrachloride (SiCl ₄ ). Metal complexes, transition element complexes and main group complexes may contain at least one element selected from the group consisting of bis(hexafluoroacetylacetonate)copper (Cu(C ₅ F ₆ HO ₂ ) ₂ ) and Dimethyl gold trifluoroacetylacetonate (Me ₂ Au(C ₅ F ₃ H ₄ O ₂ )). The organic compound may contain at least one element selected from the group consisting of carbon monoxide (CO), carbon dioxide (CO ₂ ), aliphatic hydrocarbons, aromatic hydrocarbons, components of vacuum pump oil, and volatile organic compounds.

The at least one etching gas may include at least one element selected from the group consisting of halogen-containing compounds and oxygen-containing compounds. The halogen-containing compound may contain at least one element selected from the group consisting of fluorine (F ₂ ), chlorine (Cl ₂ ), bromine (Br ₂ ), iodine (I ₂ ), xenon difluoride (XeF ₂ ) dichloride Xenon (XeCl ₂ ), xenon tetrachloride (XeCl ₄ ), dixenon tetrafluoride (Xe ₂ F ₄ ), hydrofluoric acid (HF), hydrogen iodide (HI), hydrogen bromide (HBr), nitrous Acyl chloride (NOCl), phosphorus trichloride (PCl ₃ ), phosphorus pentachloride (PCl ₅ ), phosphorus trifluoride (PF ₃ ). Oxygenates may contain at least one element selected from the following group: oxygen (O ₂ ), ozone (O ₃ ), water vapor (H ₂ O), heavy water (D ₂ O), hydrogen peroxide (H ₂ O ₂ ), nitrous oxide (N ₂ O), nitrogen oxides (NO), nitrogen dioxide (NO ₂ ) and nitric acid (HNO ₃ ). Patent application No. US2012/0273458A1 pointed out a number of further etching gases.

The at least one additive gas may comprise at least one element selected from the group consisting of oxidizing agents, halides and reducing agents.

The oxidizing agent may contain at least one element selected from the following group: oxygen (O ₂ ), ozone (O ₃ ), water vapor (H ₂ O), hydrogen peroxide (H ₂ O ₂ ), nitrous oxide (N ₂ O), nitrogen oxides (NO), nitrogen dioxide (NO ₂ ) and nitric acid (HNO ₃ ). The halide may contain at least one element selected from the following group: chlorine (Cl ₂ ), hydrochloric acid (HCl), xenon difluoride (XeF ₂ ), hydrofluoric acid (HF), iodine (I ₂ ), hydrogen iodide (HI), bromine (Br ₂ ), hydrogen bromide (HBr), nitrosyl chloride (NOCl), phosphorus trichloride (PCl ₃ ), phosphorus pentachloride (PCl ₅ ) and phosphorus trifluoride (PF ₃ ). The reducing agent may contain at least one element selected from the group consisting of hydrogen (H ₂ ), ammonia (NH ₃ ), and methane (CH ₄ ).

Irradiating the test element with a focused particle beam while providing at least one deposition gas locally induces a deposition reaction on the test element. When the at least one-step-high upper plane is illuminated by the beam tail of the focused particle beam while at least one deposition gas is provided, the particles at the beam tail can cause a localized chemical reaction that deposits material on the at least one-step-high upper plane. When the at least one opening in the hard mask is illuminated by the tail of the focused particle beam while at least one deposition gas is provided, the particles at the tail of the beam cause a localized chemical reaction that deposits material in the at least one opening in the hard mask. Material deposited in at least one opening of the hard mask may be deposited on the top side of the base element of the test element.

Irradiating the test element with a focused particle beam while providing at least one etching gas locally induces an etching reaction on the test element. When the at least one-step-high upper plane is irradiated by the beam tail of the focused particle beam while at least one etching gas is provided, the particles of the beam tail can initiate a localized chemical reaction that etches material from the at least one-step-high upper plane. When the at least one opening of the hard mask is illuminated by the tail of the focused particle beam while at least one etching gas is provided, the particles at the tail of the beam induce a localized chemical reaction that etches material in the at least one opening of the hard mask. The material etched in at least one opening of the hard mask may be etched on the top side of the base element of the test element.

Said measuring the at least one change of the test element comprises at least one element of the following group: - scanning at least the area of the test element covered by the particle beam with a measuring probe of a scanning probe microscope; - scanning at least the area of the test element covered by the at least one tail of the focused particle beam using a measuring probe of a scanning probe microscope; - scanning at least the area of the test element covered by the particle beam with a detection beam and analyzing the particles generated by the detection beam; - scanning at least the area of the test element covered by the at least one tail of the focused particle beam with a detection beam, and analyzing particles generated by the detection beam; - imaging at least the area of the test element covered by the particle beam using an optical system; - imaging at least the area of the test element covered by the at least one tail of the focused particle beam using an optical system; - preparing at least a portion of the area of the test element covered by the particle beam or the at least one tail of the focused particle beam, and imaging the prepared portion of the test element using an electron beam of a transmission electron microscope.

Said measuring the at least one variation of the test element comprises at least one element of the following group: - a scanning probe scan using a scanning probe microscope (1780) consisting of 2x2, preferably 5x5, more preferably 10x10, An area of 0.01 cm ² , preferably 0.1 cm 2 , more preferably 1 cm ² , and most preferably 5 ^{cm 2 of} the test element covered by preferably 20x20 measuring points; , preferably 5x5, more preferably 10x10, and most preferably 20x20 measurement points of the test element covered by 0.01cm ² , preferably 0.1cm ² , more preferably 1cm ² , and most preferably 5cm ² area; - using an optical system to image 0.01 cm 2 , preferably 0.1 cm ² , more preferably 1 cm of the test element covered by 2x2, preferably 5x5, more preferably ^10x10 , most preferably 20x20 measurement points ² , and the best is an area of 5cm ² .

Correspondingly designed test elements may be provided as part of the methods outlined herein, but also independently thereof. For example, the test element may comprise at least 0.01 cm ² , preferably at least 0.1 cm ² , more preferably at least Areas of 1 cm ² , preferably at least 5 cm ² , for example in the form of pillars, holes, checkerboard patterns, and/or structural elements etc. as outlined herein. This may allow residual variation to be determined, for example, by spontaneous etch/deposition processes, and/or etch or deposition rates of such processes on a larger scale.

When a test element is irradiated with a fixed focused particle beam, a portion of the entire three-dimensional (3-D) intensity distribution of the beam tail is imaged into or onto the test element. Thus, a portion of the 3-D beam tail can be detected. However, a possible disadvantage of this process mechanism is poor signal-to-noise ratio, which may limit the accuracy of beam tail determination.

Conversely, if the focused particle beam is scanned along the edge of the test structure, the 3-D intensity distribution at the beam tail is reduced to a two-dimensional (2-D) intensity distribution along the edge, ie it is averaged parallel to the scan direction. In this way a two-dimensional profile comprising an image representation of the beam tail in or on the test structure is produced with an improved signal-to-noise ratio. Or in other words: when a focused particle beam is scanned along an edge, the effect of the beam tail is distributed over an area. Averaging the variable regions produces a beam tail profile with improved signal-to-noise ratio.

The scanning probe microscope may comprise at least one element of the following group: atomic force microscope (AFM), magnetic force microscope (MFM), scanning tunneling microscope (STM), scanning near-field optical microscope (SNOM), and scanning near-field Acoustic Microscopy (SNAM). A scanning probe microscope may comprise one or more measurement probes operating in parallel.

The scanning probe microscope is capable of measuring changes in the layout of a test element caused by irradiating the test element with at least one tail of a focused particle beam in combination with at least one etching gas. Combined with at least one etching gas, the at least one beam tail can change the layout of the upper plane or the lower plane of at least one step by etching or depositing materials. It is presently preferred to change the upper plane of at least one order of height. In combination with at least one precursor gas, the at least one tail can alter the layout of the hard mask and/or at least one opening of the hard mask by etching or depositing material. It is presently preferred to change at least one opening of the hard mask.

If the hard mask is applied to the base element of the test element, at least one tail of the focused particle beam combines with at least one precursor gas to alter the base element of the test element. It may be advantageous to remove the hard mask from the test element before scanning at least one opening of the hard mask with the measurement probe of the scanning probe microscope. The hard mask can be removed by performing an etch process. The etching process may be a particle beam induced etching process. It is advantageous to employ the etching gas used to remove the hard mask from the test element to the material of the hard mask.

The detection beam may be a focused particle beam. However, it is also possible to use different particle types for the detection beam and the focused particle beam. For example, a detection beam can use electrons, and a focused particle beam can use ions. The particles generated in the test element irradiated by the detection beam can be SE and/or BSE. Furthermore, photons can be used to measure changes in the test element caused by at least one tail of the focused particle beam, and the photons can be subjected to X-ray analysis. In addition, Auger electrons generated by the detection beam can be analyzed.

The optical system may comprise at least one element of the following group: Confocal Laser Scanning Microscope (CLSM), Scanning Near Field Optical Microscope (SNOM), Aerial Image Generating Microscope, and Interferometer.

Measuring at least one change in the test structure may include scanning at least a monolayer region covered by at least one of: a particle beam, a beam tail of a focused particle beam, and at least one precursor gas with a detection beam, and detecting at least the covered region Secondary electron contrast in .

As in the above embodiment, the detection beam can use the same particle type as the focused particle beam; this embodiment is advantageous, but the same particle beam source can be used to modify the monolayer and to analyze the resulting changes. If the detection beam and the focused particle beam use particles with mass, the kinetic energy of the particle incident on the monolayer is the parameter that differs with respect to these beams. The detection beam preferably uses electrons to scan the monolayer illuminated by the focused particle beam. In the monolayer image produced by SE electrons, small changes of the monolayer can already be presented.

However, it is also possible to use different particle types for the detection beam and the focused particle beam.

The at least one monolayer may comprise self-assembled organic compounds.

Self-assembled organic compounds (SAM, self-assembled monolayers) can be formed while submerging the substrate in a surface-active solution or suspension or organic substance. The thickness of the self-assembled organic compound may range from 0.1 nm to 50 nm, preferably from 0.5 nm to 20 nm, more preferably from 0.8 nm to 10 nm, and most preferably from 1 nm to 5 nm.

For example, alkanethiols or alkyltrichlorosilanes are formed from combination compounds. For example, alkanes or alkanethiols with chain lengths of 8 (C ₈ H ₁₇ SH ) to 15 carbon atoms (C ₁₅ H ₃₁ SH ) can form monolayers with a thickness suitable for imaging beam tails. The primary electrons at the tail of the beam and the SE generated by the primary electrons can interact with the monolayer. Thus, electron beam-induced reactions can occur in the monolayer. This interaction is accompanied by energy transfer from primary electrons and/or SE to monolayer carbon chain carbon atoms. The electrons (usually particles) at the tail of the beam can change the chain length of the alkane, that is, shorten the chain length by breaking the alkane chain caused by the particle beam. In addition, particles at the beam tail of the focused particle beam can alter thiol groups or terminal functional groups located at the ends of alkyl chains at a distance from the monolayer surface. The detection beam can be used to analyze the change(s) of the monolayer, eg by induced SE contrast changes.

The test element comprises at least one layer containing at least one element of the following: gold (Au), silver (Ag), platinum (Pt), copper (Cu), graphite (C) and silicon (Si).

Test elements produced from silicon wafers are therefore directly suitable, ie without depositing another layer, for forming test structures in the form of a single layer. In contrast, producing a test element from a substrate of an optical mask requires the deposition of a thin metal layer made of one of the aforementioned elements, so that a stable self-assembled monolayer can be formed on the test element as a test structure.

A single layer can be applied to one of several of the above test structures. The monolayer variation induced by the beam tail of the focused particle beam, which is substantially unaffected by the main beam due to the spatial separation between the main beam and the beam tail, can be used to determine the intensity profile of the beam tail of the particle beam.

The substrate element may be adapted such that the particle beam induced etching process does not substantially etch the substrate element of the test structure, and at least one structural element of the test structure may comprise at least one pillar to be etched during the particle beam induced etching process.

The structural element may comprise at least two pillars adapted such that the particle beam induced etching process does not substantially etch the at least two pillars, and the base element comprises a material to be etched during the particle beam induced etching process.

The at least one structural element may comprise at least one aperture mask adapted such that the particle beam induced etching process does not substantially etch the at least one aperture mask, and the substrate element may be adapted such that the particle beam induced etching process etches the substrate element.

The aperture mask may include at least two openings to define variations of the base element.

A computer program comprising a plurality of instructions that, when executed by a computer system, causes the computer system to perform steps in one of the methods described herein.

In a further embodiment, an apparatus for determining an intensity distribution of a particle beam on a sample comprises: (a) irradiating means for irradiating a test element with the particle beam such that the particle beam induces at least a change; and (b) measuring means for measuring the at least one change of the test element to determine an intensity distribution of the particle beam on the sample.

The device for determining the intensity distribution may further comprise focusing means for focusing the particle beam.

The device for determining the intensity distribution may further comprise providing means for providing at least one precursor gas on the sample and/or the test element.

The means for providing the at least one precursor gas may include setting means for setting a gas flow rate, a temperature, a pressure and/or a density of the at least one precursor gas.

The device for determining the intensity distribution may further comprise measuring means for measuring the at least one change of the test element.

The device for determining the intensity distribution may further comprise determining means for determining the intensity distribution of the particle beam from the at least one measured change of the test element.

In another embodiment, an apparatus for determining an intensity distribution of at least one tail of a focused particle beam comprises: (a) a setting unit configured to set at least one parameter of the focused particle beam such that when a test the focused particle beam causes at least one measurable change in the test element when the component is irradiated by the focused particle beam; and (b) a measurement unit configured to measure the change in the test element to determine the at least one measurable change in the focused particle beam The intensity variation of a bunch of tails.

The setting unit can set various parameters of the particle beam source and/or the particle beam imaging system. The adjustable parameters of the setting unit may include: the kinetic energy of the particle beam with mass, the beam waist diameter of the focused particle beam, the position of the beam waist diameter in the beam direction, the beam current, the scanning scheme, the aperture angle of the focused particle beam and the dissipation set up. A scanning scheme describes the motion of a focused particle beam in a plane.

Furthermore, the setting unit may be configured to set parameters of the detection beam. The parameters of the detection beam may include parameters of the focused particle beam. Furthermore, the setting unit may be configured to set various parameter settings of the detection device of the detection beam. The parameters of the detection device may include: the accelerating voltage of the detector, the energy filter of the detector and the type of detector.

The device may further include a holding device for the test element. The holding device for the test element can be a separate unit from the sample holder.

A test element may contain several test structures. Thus, during the service life of the device, a single test element can be reused, if necessary, to analyze at least one tail of the focused particle beam of the device. However, it is also possible to use a dedicated test element for each individual analysis procedure of at least one tail. In addition, the apparatus for manufacturing the test element can also be used.

The holding device may comprise a positioning unit configured to position the test element below the focused particle beam and/or below the measurement unit.

The positioning unit may comprise one or more micromanipulators capable of moving the test element in one, two or three spatial directions.

Furthermore, the device may comprise a computing unit configured to determine an intensity distribution of the at least one tail of the focused particle beam from the measured variation of the test element.

According to yet another exemplary embodiment of the present invention, this problem is at least partially solved by the objects of the independent embodiments 1 and 17 of the present application. Further example embodiments are described in the appended claims.

In Example 1, a method for determining the intensity distribution of a particle beam on a sample comprises the steps of: (a) irradiating a test element with the particle beam such that the particle beam causes at least one measurable change in the test element and (b) measuring the at least one change of the test element to determine an intensity distribution of the particle beam on the sample.

An ideal Gaussian beam can be easily divided into a main or central beam, and a beam tail. Starting from the intensity maximum _I0 , the main beam is defined as the region of intensity greater than the critical value associated with the intensity maximum. For example, the critical value can be defined as I>I ₀ ·e ^-2 . Beam tails are formed by regions with intensities less than a specified relative critical value, eg I<I ₀ ·e ⁻² .

The beam profile described in this application can deviate significantly from the ideal Gaussian intensity distribution. However, in this application the main or central beam is defined to resemble an ideal Gaussian beam. This means that the intensity maximum value I ₀ of the beam is determined in a first step. Then, a certain percentage drop off from the maximum value is assigned as the threshold marking the boundary between the center beam and the beam tail. For a real particle beam, the beam tail is formed by the entire intensity directed outside the central beam. This definition does not imply that the intensity must remain below a given critical value at every point of the beam tail, but that the intensity can grow again with increasing distance from the intensity maximum. Furthermore, compared to an ideal Gaussian beam, a real beam may have a beam tail whose intensity profile does not extend rotationally symmetric around the intensity maximum _I0 . Hereinafter, this case is characterized by having two or more bundle tails. Preferably, these definitions (main beam and beam tail) relate to the focal point or the region near the focal point where the beam waist diameter of the focused particle beam does not increase by more than a factor of 2 relative to the diameter of the focal spot.

The method facilitates quantitative analysis of the beam tail of a focused particle beam by interacting with a test element to make visible the effects of particles contained in the beam tail. The detection process can be performed in such a way that the particles of the main beam of the focused particle beam have substantially no influence on the variation of the test element.

The intensity distribution of the beam tail of the focused particle beam can be quantitatively determined from visible or measurable changes in the test element. Knowledge of the intensity distribution over the entire area illuminated by the focused particle beam can be used to optimize the images produced by scanning the sample with the focused particle beam. Furthermore, knowledge about the intensity of the focused particle beam present in the beam tail can be used to optimize local particle beam induced processing of the sample. For example, knowledge of the intensity distribution of the beam tail of a focused particle beam may allow minimizing the number of cycle iterations required for the best possible repair of a defect.

The particles of the particle beam may be particles with no rest mass, such as photons; in this case, the intensity of the particle beam is directly proportional to the electrical energy density distribution. However, the particles of the particle beam may also be particles with mass, such as electrons, atoms, ions or molecules; in these cases the intensity is proportional to the absolute value squared of the amplitude of the wave function of the corresponding particle type.

Irradiating the test element can cause at least one layout change, at least one chemical change, and/or at least one physical change of the test element.

The change(s) of the test element can be measured. Assuming that the induced change(s) in the test element are directly proportional to the local effective intensity, the particle dose distribution in the beam tail of the focused particle beam can be derived from the measured change(s).

The test element has at least one test structure, which includes at least one element of the following groups: - at least one order high; - at least one hard mask having at least one opening; and - At least one single layer.

The at least one step defines an upper plane by the top side of the step and a lower plane by the lower edge of the step. The hard mask designates the top side as the side on which the focused particle beam is incident on the hard mask, and designates the back side opposite the top side. The upper and lower planes of the at least one step height, and the top and back sides of the hard mask may be substantially flat. Furthermore, the upper and lower planes of the at least one step height, and the top and back sides of the hard mask may form substantially parallel planes. The parallelism of the upper and lower planes or the top and back sides of the hard mask can improve the accuracy of determining the intensity distribution of the beam tail of the focused particle beam.

The test structure can include at least one step and a single layer, and/or the test structure can include a hard mask with at least one opening and can include a single layer.

The test element may include a base element. The top side of the base element may form the at least one step-high lower plane. The base element of the test element can be the substrate of the optical mask. The at least one step height can be a pattern element of an optical mask. The base element of the test device can be the base material of the optical mask or the wafer, and one or more steps can be etched into the optical mask or the base material of the wafer, and/or can be formed by the optical mask or the base material of the wafer. Wafers are produced by depositing materials on a substrate.

A hard mask can be applied to the top side of the base element of the test element. At least one opening of the hard mask may expose a portion of the top side of the base element. At least one opening of the hard mask can be created by etching.

A hard mask is a mask that is resistant to prolonged exposure to a focused particle beam for much longer periods of time than a polymer mask made of photoresist. For example, the hard mask can include a metal layer, an oxide layer, or a nitride layer.

Here and in this description, the term "substantially" denotes the indication of a measured quantity within the measurement uncertainty when the corresponding quantity is measured using measuring equipment according to the prior art.

The at least one step and/or the at least one opening has at least one edge, and/or wherein the monolayer is designed to alter secondary electron contrast when irradiated with the focused particle beam.

At least one step and/or at least one edge of at least one opening of the hard mask may be arranged on an upper plane of the at least one step and/or a top side of the hard mask. The at least one edge may comprise a cross-sectional straight edge.

A single layer may be applied to the at least one step, to a hard mask having at least one opening, and/or to a base element of a test element. The intensity distribution of the beam tail of the focused particle beam may be determined from the variation applied to the at least one high-order monolayer and/or from the variation applied to the monolayer in the at least one opening of the hard mask.

The method may further include: setting the height of the at least one step height, and/or the thickness of the hard mask, so that the beam area of the focused particle beam increases by at least 2%, preferably 5%, more preferably 10%, and most preferably 30%.

The beam waist of the focused particle beam may have a diameter < 20 nm, preferably < 10 nm, more preferably < 5 nm, and most preferably < 2 nm.

In the following, both the beam waist diameter and the focal spot diameter are related to the intensity drop to e ^-2 , that is, the intensity drops to 13.5% of the maximum intensity. If the main beam of a focused particle beam is based on this definition, the main beam of an ideal Gaussian beam carries about 93% of the particles, and the beam tail carries about 7%. Aberrations in real particle optics can lead to an increased fraction of particles contained in the beam tail.

The test element may have N test structures or structural elements, which include the range of 1≤N≤1000, preferably 5≤N≤500, more preferably 10≤N≤100, most preferably 20≤N≤50. A test element with N identical test structures can be used for N calibration measurements of the intensity distribution of the particle beam and/or the beam tail of the focused particle beam. This test element can be installed into the device during its production, which can then be used to analyze the beam, or focus the particle beam after each service, after modification, and/or after the device is serviced during its service life beam tail. In addition, test elements can be used to study the effects of spontaneous handling on samples. However, it is also possible to introduce the test element into the device before analyzing one or more beam tails of the focused particle beam.

The test device may include at least two test structures from the group: at least one step, a hard mask with at least one opening, and a single layer.

Two or three different types of test structures can be combined on one test element. Thus, the accuracy with which the intensity distribution of the beam tail of the focused particle beam can be determined can be optimized.

Irradiating the test element may include: focusing the particle beam on at least one element of the following group: - an upper plane of the at least one step, and/or a rear side of the hard mask; - a lower plane of the at least one step, and/or a top side of the hard mask; - a top side of the single layer.

Embodiments in which the focused particle beam is focused on at least one higher lower plane and/or the top side of the hard mask are presently preferred. In these embodiments an optimal separation of the beam tails from the central or main part of the focused particle beam can be obtained and thus the dose distribution of one or more beam tails can be analyzed with minimal influence of the main beam.

In embodiments where the focused particle beam is focused on the upper plane of at least one step and/or the underside of the hard mask, some particles generated by the main beam in the step or hard mask will enter the region of the beam tail, Thus, in addition to changing the intensity distribution of the beam tail, the test structure of the test element is also changed. This can make analysis of the dose distribution of one or more beam tails of the focused particle beam more difficult.

Particles generated by the focused particle beam in the test element may contain secondary electrons (SE) and/or backscattered electrons (BSE) from the test element.

In the upper plane or top side of the hard mask, at least one step and/or at least one cross-sectional straight edge of at least one opening of the hard mask may comprise an angle α in the range of 60°<α<120°, It is preferably within the range of 75°<α<105°, more preferably within the range of 85°<α<95°, most preferably within the range of 89°<α<91°.

The at least one height may include at least two heights, which are arranged symmetrically with respect to a line of symmetry, which may lie in a lower plane. The at least one step preferably comprises at least four steps, the edges of which have substantially an angle of 90° to each other.

The hard mask may include at least two openings, which are symmetrically arranged with respect to the incident point of the focused particle beam on the hard mask, and/or symmetrically arranged with respect to at least one scanning direction of the focused particle beam. The at least one opening of the hard mask preferably has a rectangular shape. A slot-shaped opening of the hard mask, in particular in the form of a concentric structure, eg a ring around the point of incidence of the focused particle beam on the hard mask, is also advantageous.

With respect to the upper plane of the step or the top side of the hard mask, at least one edge of at least one step and/or at least one edge of at least one opening of the hard mask may comprise an angle β in the range 60°<β<120 °, preferably within the range of 75°<β<105°, more preferably within the range of 85°<β<95°, most preferably within the range of 89°<β<91°.

Having a right angled step between the lower and upper planes, or a right angled hard mask opening between the top side and the back side increases the resolution in determining the beam tail dose distribution of the focused particle beam.

Irradiating the test element may comprise at least one element of the following group: - irradiating at least one point of the lower plane of the at least one step with the focused particle beam such that the at least one beam tail is incident on an upper plane of the at least one step; - scanning the focused particle beam along at least one edge of the at least one step such that the at least one tail of the focused particle beam is incident on the upper plane of the at least one step; - irradiating at least one point of the hard mask with the focused particle beam such that at least a portion of the at least one beam tail is incident on the at least one opening in the hard mask; - scanning the focused particle beam parallel to the at least one edge of the at least one opening in the hard mask such that at least a portion of the at least one beam tail is incident on the at least one opening in the hard mask; - irradiating at least a point of the monolayer.

Irradiating the test element comprises at least one element of the following group: - selecting a distance between an intensity maximum of the focused particle beam and the at least one edge of the at least one step such that particles generated by the focused particle beam in the lower plane of the at least one step are substantially free of reaching the upper surface of the at least one step; - selecting a distance between the intensity maximum of the focused particle beam and the at least one edge of the at least one opening in the hard mask such that particles produced by the focused particle beam in the hard mask are substantially free of reaches into the at least one opening; - selecting the energy of the focused particle beam such that substantially none of the particles of the focused particle beam reach a rear side of the monolayer.

The main part of the focused particle beam can generate secondary particles such as SE and/or BSE in the lower plane of the test element or in the substrate element. These particles should not reach the at least first-order high upper plane, otherwise they could mix with particles of the beam tail or with secondary particles generated from the beam tail and thus cover the detection of changes in the test element caused by the beam tail. The same applies to particle beams incident on hard masks. By spatially separating the influence of the main beam and the influence of the beam tail, the dose distribution at the beam tail can be analyzed substantially independent of interference from the main beam of the focused particle beam.

When irradiating a monolayer with a focused particle beam, the kinetic energy of the particles can be set such that these particles are virtually unable to penetrate into the test element to which the monolayer has been applied, so secondary particles generated in the test element cannot change the chemical composition of the monolayer and/or structure.

Irradiating the test element may comprise scanning the focused particle beam along at least one edge of the at least two-step height in at least two different distances between an intensity maximum of the focused particle beam and at least one edge of the at least two-step height.

By varying the distance between the intensity maxima of the focused particle beam and the edges of the multiple steps, the best possible positioning of the focused particle beam for scanning along the edges of the first steps can be determined. This minimizes the influence of the main beam on the analysis of one or more beam tails.

Irradiating the test element may include providing at least one precursor gas in the region of at least one tail of the focused particle beam. Test elements undergo layout changes by performing localized particle beam-induced chemical reactions. The spatial separation of the main beam and the one or more beam tails of the focused particle beam enables the intensity distribution of the one or more beam tails to be visible (ie, measurable) independent of interference from the main beam.

The at least one precursor gas may include at least one element selected from the group consisting of at least one etching gas, at least one deposition gas, and at least one additive gas.

The at least one deposition gas may comprise at least one element selected from the following group: metal alkyl, transition element alkyl, main group alkyl, metal carbonyl, transition element carbonyl, main group carbonyl, metal alkoxide, transition element alcohol Salts, main group alkoxides, metal complexes, transition element complexes, main group complexes and organic compounds.

Metal alkyl, transition element alkyl and main alkyl group may contain at least one element selected from the group consisting of: cyclopentadienyl (Cp) trimethylplatinum (CpPtMe ₃ ), methylcyclopentadienyl ( MeCp) trimethylplatinum (MeCpPtMe ₃ ), tetramethyltin (SnMe ₄ ), trimethylgallium (GaMe ₃ ), ferrocene (Cp ₂ Fe) and bisaryl chromium (Ar ₂ Cr). Metal carbonyls, carbonyl transition elements and carbonyl main groups may contain at least one element selected from the group consisting of chromium hexacarbonyl (Cr(CO) ₆ ), molybdenum hexacarbonyl (Mo(CO) ₆ ), tungsten hexacarbonyl (W( CO) ₆ ), dicobalt octacarbonyl (Co ₂ (CO) ₈ ), triruthenium dodecacarbonyl (Ru ₃ (CO) ₁₂ ), and iron pentacarbonyl (Fe(CO) ₅ ). Metal alkoxides, transition element alkoxides and main group alkoxides may contain at least one element selected from the group consisting of tetraethyl orthosilicate (TEOS, Si(OC ₂ H ₅ ) ₄ ) and titanium tetraisopropoxide (Ti(OC ₃ H ₇ ) ₄ ). Metal halides, transition element halides and main group halides may contain at least one element selected from the group consisting of: tungsten hexafluoride (WF ₆ ), tungsten hexachloride (WCl ₆ ), titanium tetrachloride (TiCl ₄ ), boron trichloride (BCl ₃ ) and silicon tetrachloride (SiCl ₄ ). Metal complexes, transition element complexes and main group complexes may contain at least one element selected from the group consisting of bis(hexafluoroacetylacetonate)copper (Cu(C ₅ F ₆ HO ₂ ) ₂ ) and Dimethyl gold trifluoroacetylacetonate (Me ₂ Au(C ₅ F ₃ H ₄ O ₂ )). The organic compound may contain at least one element selected from the group consisting of carbon monoxide (CO), carbon dioxide (CO ₂ ), aliphatic hydrocarbons, aromatic hydrocarbons, components of vacuum pump oil, and volatile organic compounds.

The at least one etching gas may include at least one element selected from the group consisting of halogen-containing compounds and oxygen-containing compounds. The halogen-containing compound may contain at least one element selected from the group consisting of fluorine (F ₂ ), chlorine (Cl ₂ ), bromine (Br ₂ ), iodine (I ₂ ), xenon difluoride (XeF ₂ ), dichloro Xenon (XeCl ₂ ), xenon tetrachloride (XeCl ₄ ), dixenon tetrafluoride (Xe ₂ F ₄ ), hydrofluoric acid (HF), hydrogen iodide (HI), hydrogen bromide (HBr), Nitrogen chloride (NOCl), phosphorus trichloride (PCl ₃ ), phosphorus pentachloride (PCl ₅ ), phosphorus trifluoride (PF ₃ ). Oxygenates may contain at least one element selected from the following group: oxygen (O ₂ ), ozone (O ₃ ), water vapor (H ₂ O), heavy water (D ₂ O), hydrogen peroxide (H ₂ O ₂ ), nitrous oxide (N ₂ O), nitrogen oxides (NO), nitrogen dioxide (NO ₂ ) and nitric acid (HNO ₃ ). Other etching gases are indicated in patent application US2012/0273458A1.

The at least one additive gas may comprise at least one element selected from the group consisting of oxidizing agents, halides and reducing agents.

The oxidizing agent may contain at least one element selected from the following group: oxygen (O ₂ ), ozone (O ₃ ), water vapor (H ₂ O), hydrogen peroxide (H ₂ O ₂ ), nitrous oxide (N ₂ O), nitrogen oxides (NO), nitrogen dioxide (NO ₂ ) and nitric acid (HNO ₃ ). The halide may contain at least one element selected from the following group: chlorine (Cl ₂ ), hydrochloric acid (HCl), xenon difluoride (XeF ₂ ), hydrofluoric acid (HF), iodine (I ₂ ), hydrogen iodide (HI), bromine (Br ₂ ), hydrogen bromide (HBr), nitrosyl chloride (NOCl), phosphorus trichloride (PCl ₃ ), phosphorus pentachloride (PCl ₅ ) and phosphorus trifluoride (PF ₃ ). The reducing agent may contain at least one element selected from the group consisting of hydrogen (H ₂ ), ammonia (NH ₃ ), and methane (CH ₄ ).

Irradiating the test element with a focused particle beam while providing at least one deposition gas locally induces a deposition reaction on the test element. When the at least one-step-high upper plane is illuminated by the beam tail of the focused particle beam while at least one deposition gas is provided, the particles at the beam tail can cause a localized chemical reaction that deposits material on the at least one-step-high upper plane. When the at least one opening in the hard mask is illuminated by the tail of the focused particle beam while at least one deposition gas is provided, the particles at the tail of the beam cause a localized chemical reaction that deposits material in the at least one opening in the hard mask. Material deposited in at least one opening of the hard mask may be deposited on the top side of the base element of the test element.

Irradiating the test element with a focused particle beam while providing at least one etching gas locally induces an etching reaction on the test element. When the at least one-step-high upper plane is irradiated by the beam tail of the focused particle beam while at least one etching gas is provided, the particles of the beam tail can initiate a localized chemical reaction that etches material from the at least one-step-high upper plane. When the at least one opening of the hard mask is illuminated by the tail of the focused particle beam while at least one etching gas is provided, the particles at the tail of the beam induce a localized chemical reaction that etches material in the at least one opening of the hard mask. The material etched in at least one opening of the hard mask may be etched on the top side of the base element of the test element.

Said measuring the at least one change of the test element comprises at least one element of the following group: - scanning at least the area of the test element covered by the at least one tail of the focused particle beam using a measuring probe of a scanning probe microscope; - scanning at least the area of the test element covered by the at least one tail of the focused particle beam with a detection beam, and analyzing particles generated by the detection beam; - imaging at least the area of the test element covered by the at least one tail of the focused particle beam using an optical system; - preparing at least a portion of the area of the test element covered by the at least one tail of the focused particle beam, and imaging the prepared portion of the test element using an electron beam of a transmission electron microscope.

When a test element is irradiated with a fixed focused particle beam, a portion of the entire three-dimensional (3-D) intensity distribution of the beam tail is imaged into or onto the test element. Thus, a portion of the 3-D beam tail can be detected. However, a possible disadvantage of this processing mechanism is poor signal-to-noise ratio, which may limit the accuracy of beam tail determination.

In contrast, if the focused particle beam is scanned along the edge of the test structure, the 3-D intensity distribution at the beam tail is reduced to a two-dimensional (2-D) intensity distribution along the edge, ie it is averaged parallel to the scan direction. A two-dimensional profile containing an image representation of the beam tail in or on the test structure is thus produced with an improved signal-to-noise ratio. Or in other words: when a focused particle beam is scanned along an edge, the effect of the beam tail is distributed over an area. Averaging the variable regions produces a beam tail profile with an improved signal-to-noise ratio.

A scanning probe microscope may comprise at least one element of the following groups: atomic force microscope (AFM), magnetic force microscope (MFM), scanning tunneling microscope (STM), scanning near-field optical microscope (SNOM), and scanning near-field Acoustic Microscopy (SNAM). A scanning probe microscope may comprise one or more measurement probes operating in parallel.

The scanning probe microscope is capable of measuring changes in the layout of a test element caused by irradiating the test element with at least one tail of a focused particle beam in combination with at least one etching gas. Combined with at least one etching gas, the at least one beam tail can change the layout of the upper plane or the lower plane of at least one step by etching or depositing materials. It is presently preferred to change the upper plane of at least one order of height. In combination with at least one precursor gas, the at least one tail can alter the layout of the hard mask and/or at least one opening of the hard mask by etching or depositing material. It is presently preferred to change at least one opening of the hard mask.

If the hard mask is applied to the base element of the test element, at least one tail of the focused particle beam combines with at least one precursor gas to alter the base element of the test element. It may be advantageous to remove the hard mask from the test element before scanning at least one opening of the hard mask with the measurement probe of the scanning probe microscope. The hard mask can be removed by performing an etch process. The etching process may be a particle beam induced etching process. It is advantageous to adapt the etching gas to remove the hard mask from the test element to the material of the hard mask.

The detection beam may be a focused particle beam. However, it is also possible to use different particle types for the detection beam and the focused particle beam. For example, a detection beam can use electrons, and a focused particle beam can use ions. The particles generated in the test element irradiated by the detection beam can be SE and/or BSE. Furthermore, photons can be used to measure changes in the test element caused by at least one tail of the focused particle beam, and the photons can be analyzed by X-rays. In addition, Auger electrons generated by the detection beam can be analyzed.

The optical system may comprise at least one element from the following group: Confocal Laser Scanning Microscope (CLSM), Scanning Near Field Optical Microscope (SNOM), Aerial Image Generating Microscope, and Interferometer.

Measuring at least one change in the test structure may include using the detection beam to scan at least a monolayer area covered by the beam tail of the focused particle beam.

As in the above embodiment, the detection beam can use the same particle type as the focused particle beam; this embodiment is advantageous, but the same particle beam source can be used to modify the monolayer and to analyze the resulting changes. If the detection beam and the focused particle beam use particles with mass, the kinetic energy of the particle incident on the monolayer is the parameter that differs with respect to these beams. The detection beam preferably uses electrons to scan the monolayer illuminated by the focused particle beam. In the monolayer image produced by SE electrons, small changes of the monolayer can already be presented.

However, it is also possible to use different particle types for the detection beam and the focused particle beam.

The at least one monolayer may comprise a self-assembling organic compound.

Self-assembled organic compounds (SAM, self-assembled monolayers) can be formed while immersing the substrate in a solution or suspension of surface-active or organic substances. The thickness of the self-assembled organic compound may range from 0.1 nm to 50 nm, preferably from 0.5 nm to 20 nm, more preferably from .8 nm to 10 nm, and most preferably from 1 nm to 5 nm.

For example, alkanethiols or alkyltrichlorosilanes are formed from combination compounds. For example, alkanes or alkanethiols with chain lengths of 8 (C ₈ H ₁₇ SH ) to 15 carbon atoms (C ₁₅ H ₃₁ SH ) can form monolayers with a thickness suitable for imaging beam tails. The primary electrons at the tail of the beam and the SE generated by the primary electrons can interact with the monolayer. Thus, electron beam-induced reactions can occur in the monolayer. This interaction is accompanied by energy transfer from primary electrons and/or SE to monolayer carbon chain carbon atoms. The electrons (usually particles) at the tail of the beam can change the chain length of the alkane, that is, shorten the chain length by breaking the alkane chain caused by the particle beam. In addition, particles at the beam tail of the focused particle beam can alter thiol groups or terminal functional groups located at the ends of alkyl chains at a distance from the monolayer surface. The detection beam can be used to analyze the change(s) of the monolayer, eg by induced SE contrast changes.

The test element includes at least one layer made of at least one element selected from the following group: gold (Au), silver (Ag), platinum (Pt), copper (Cu), graphite (C) and silicon (Si).

Test elements produced from silicon wafers are therefore directly suitable (ie without depositing a further layer) for forming test structures in monolayer form. In contrast, producing a test element from a substrate of an optical mask requires depositing a thin metal layer made of one of the aforementioned elements, so that a stable self-assembled monolayer can be formed on the test element as a test structure.

A single layer can be applied to one of several test structures described above. The monolayer variation induced by the beam tail of the focused particle beam, which is substantially unaffected by the main beam due to the spatial separation between the main beam and the beam tail, can be used to determine the intensity profile of the beam tail of the particle beam.

A computer program containing a plurality of instructions. When a computer system executes the computer program, it causes the computer system to perform a plurality of steps of one of the above-mentioned methods.

In embodiment 17, an apparatus for determining an intensity distribution of a particle beam on a sample comprises: (a) a setting unit configured to set at least one parameter of the focused particle beam such that when a test element is subjected to the focused upon irradiation with a particle beam, the focused particle beam causes at least one measurable change in the test element; and (b) a measurement unit configured to measure the at least one change in the test element to determine the at least one change in the focused particle beam The intensity variation of the beam tail.

The setting unit can set various parameters of the particle beam source and/or the particle beam imaging system. The adjustable parameters of the setting unit may include: the kinetic energy of the particle beam with mass, the beam waist diameter of the focused particle beam, the position of the beam waist diameter in the beam direction, the beam current, the scanning scheme, the aperture angle of the focused particle beam and the dissipation set up. A scanning scheme describes the motion of a focused particle beam in a plane.

Furthermore, the setting unit may be configured to set parameters of the detection beam. The parameters of the detection beam may include parameters of the focused particle beam. Furthermore, the setting unit may be configured to set various parameter settings of the detection device of the detection beam. The parameters of the detection device may include: the accelerating voltage of the detector, the energy filter of the detector and the type of detector.

The device may further include a holding device for the test element. The holding device for the test element can be a separate unit from the sample holder.

A test element may contain several test structures. Thus, during the service life of the device, a single test element can be reused, if necessary, to analyze at least one tail of the focused particle beam of the device. However, it is also possible to use a dedicated test element for each individual analysis procedure of at least one tail. In addition, the apparatus for manufacturing the test element can also be used.

The holding device includes a positioning unit configured to position the test element below the focused particle beam and/or below the measurement unit.

The positioning unit may comprise one or more micromanipulators capable of moving the test element in one, two or three spatial directions.

Furthermore, the device may comprise a computing unit configured to determine an intensity distribution of the at least one tail of the focused particle beam from the measured variation of the test element.

Presently preferred embodiments of the method according to the invention and the device according to the invention are described below. The device according to the invention is explained using the example of a scanning electron microscope (SEM) in combination with a scanning probe microscope (SPM). However, the method according to the invention and the device according to the invention are not limited to determining the beam tail of a particle beam having a mass in the form of an electron beam. Instead, these can be used to analyze the beam tail of any particle beam whose particles contain glass particles or Fermi particles. If the particle beam comprises a photon beam, the method according to the invention is especially useful for short-wavelength photons, ie photons with wavelengths in the deep ultraviolet (DUV) wavelength range, or even shorter wavelength ranges.

In addition, the methods and associated devices described in this application can be used in microscopes that record images using scanning focused particle beams. Hereinafter, a particle beam includes a particle beam having mass, and a particle beam including particles without rest mass.

FIG. 1 a schematically shows the profile of a focused particle beam 100 . The exemplary particle beam 100 includes a focused particle beam 100 . Focused particle beam 100 includes a main beam 110 (which contains a major portion of electrons), and two tails 120 and 130 . The definition of main beam 100 used in this application is as described above. Focused particle beam 100 has an intensity maximum I ₀ 190 . As schematically illustrated in Figure 1a, the profile of a focused particle beam 100 (unlike that of an ideal Gaussian beam) does not decrease monotonically from the center or intensity maximum _I0 190, and the beam profile is not centrosymmetric. This means that one or more beam tails 120 , 130 of the focused particle beam 100 are likewise not centrosymmetric; instead, in the paper, the focused particle beam 100 has two beam tails 120 , 130 that differ in view of the intensity distribution.

As already explained above, the main beam or central beam 110 is defined in this application as the region in which the intensity drops from a maximum value _I0 to a certain percentage of the maximum intensity. For example, this can be reduced to I ₀ ·e ⁻² . Beam tails 120 and 130 are formed in non-vanishing intensity regions outside the main beam 110 .

FIG. 2 illustrates a sample area exposed with a focused particle beam 100 having a narrow peak and asymmetric beam tails 120, 130. The narrow peak of the focused particle beam 100 is concentrated in a small region 200 . The next larger area represents pixels 150 of defective regions of the sample that should be processed by the focused particle beam 100 in combination with one or more precursor gases. Regions 210 , 220 , 230 and 240 represent respective portions of beam tails 120 , 130 of focused particle beam 100 . In the example reproduced in Figure 2, the beam tail is in the x-direction (in the horizontal direction), but the beam tail is symmetrical with respect to the intensity maximum in the y-direction (in the vertical direction).

Even if the intensity levels of beam tails 120, 130 in regions 210, 220, 230 and 240 are small compared to the intensity maximum of main beam 110, beam tails 120, 130 can carry the entire mass of focused particle beam 110 due to their sheer size. A significant portion of the strength. With corresponding aberrations of the optical system focusing the particle beam 100, in extreme cases up to half of the entire beam intensity may be present in the beam tail.

Referring back now to FIG. 1 , focused electron beam 100 is directed toward sample 140 . In the portion reproduced in Figure 1a, the sample 100 has defects not shown in Figure 1a. Defects in the sample 140 should be repaired by performing particle beam-induced local chemical fabrication. In the example shown in FIG. 1a, the focused electron beam 100 may perform a localized electron beam induced etching (EBIE) process and/or a localized electron beam induced deposition (EBID) process.

For the repair process, the defective area of the sample 140 is divided into pixels 150, and the focused electron beam 100 scans the pixels 150 sequentially. The focused electron beam 100 locally removes material from, or locally deposits material on, the sample 140 in combination with a corresponding precursor gas.

FIG. 1 a shows pixels 150 of a region of a sample 140 to be treated by a focused electron beam 100 . Irradiating the pixel 150 with the focused electron beam 100 also inadvertently causes the particle beam to induce localized chemical reactions in the regions 160 , 170 , 210 - 240 outside the pixel 150 due to the beam tails 120 and 130 . From Fig. 2 and Fig. 1 b (the latter also reproduces the plan view of the focused particle beam 100 on the pixel 150 of the sample 140), the beam tails 120 and 130 result in a focused particle beam many times larger than the area of the pixel 150 to be processed 100 of the processing area 180 .

In order to control, and more particularly optimize, particle beam-induced localized processing of sample 140 , knowledge of the radiation dose distribution present in beam tails 120 and 130 is thus required in addition to knowledge of the beam profile of main beam 110 . The same applies if the focused particle beam 100 is used to image the sample 140 .

Various example embodiments that facilitate quantitative analysis of the intensity distribution of the beam tails 120, 130 of the focused particle beam 100 are detailed below.

FIG. 3 shows a schematic plan view of a first exemplary embodiment of a test element 300 in the upper partial image and a schematic cross-section through the test element 300 in the lower partial image. The test element 300 includes a base element 310 and a structural element 390 . The exemplary test element 300 of FIG. 3 includes a photolithographic mask substrate 310 as the base element 310 . Two rectangular pattern elements 320 and 360 have been applied as structural elements 390 to the base element 310 of the test element 300 . Rectangular pattern elements 320 and 360 may be any pattern elements of an optical mask, such as absorbing and/or phase shifting pattern elements. These two pattern elements form at least two steps 320 and 360 . Its height 380 may range from 50nm to 2000nm. The upper plane 340 of the steps 320 , 360 forms the surface of the pattern elements 320 , 360 . The lower plane 350 with two steps 320 , 360 forms the surface 370 of the base element 310 of the test element 300 .

Edge 330 with two steps 320 , 360 represents the transition from upper plane 340 to lower plane 350 . In the example test element 300 shown in Figure 3, the edge 330 has an angle a of substantially 90°. This angle facilitates the function of the test element explained below. In FIG. 3, the edge 330 has a cross-sectional straight profile. The angle β in the upper plane 340 likewise has an angle of substantially 90°.

FIG. 4 presents a first schematic example of using a test element 300 to analyze beam tails 120 , 130 of a focused particle beam 100 . In a first step, the focus of the particle beam 100 is set onto the upper plane 340 of the steps 320 , 360 . This is illustrated schematically by the beam waist diameter 400 in the lower partial image of FIG. 4 . In a next step, the beam waist diameter 400 or intensity maxima are positioned relative to the edge 330 of the steps 320, 360 such that the main beam 110 of the focused particle beam 100 passes through on the lower plane 350 of the steps 320, 360. The edges 330 of the steps 320 , 360 and the beam tail 120 are focused on the upper plane 340 of the steps 320 , 360 . The optimal positioning of the focused particle beam 100 relative to the edge 330 can be determined experimentally by varying the distance between the intensity maximum I ₀ of the focused particle beam 100 and the edge 330 .

After this alignment, a precursor gas is provided in the region of the beam tail 120 and is irradiated for a predetermined duration by the particle beam 100 which has been optimally aligned relative to the edge 330 . The precursor gas in the form of an etching gas locally removes material from the upper plane 340 of the steps 320, 360 caused by the combined effect of the particles of the beam tail 120 and the etching gas. For example, a halogen-containing etching gas, such as xenon difluoride (XeF ₂ ), may be used as the etching gas. If a deposition gas is provided in the region of the beam tail 120 , the intensity distribution of the beam tail 120 causes material to be deposited on the upper plane 340 of the steps 320 , 360 . For example, metal carbonyls, such as chromium hexacarbonyl (Cr(CO) ₆ ), can be used as deposition gases. Changing the upper plane 340 of the steps 320 , 360 by etching or depositing material continues to map the intensity distribution of the beam tail 120 into the upper plane 340 of the steps 320 , 360 of the test element 300 .

Spatial separation of the influence of the main beam 110 and the beam tail 120 of the focused particle beam 100 facilitates the visible or measurable reproduction of the intensity distribution of the beam tail 120 . The provision of the precursor gas cannot be spatially concentrated to such an extent that the gas molecules of the precursor gas are only present on the upper plane 340 of the steps 320 , 360 . This means that the main beam 110 of the focused particle beam 100 also changes the lower plane 350 of the steps 320 , 360 , just like (to a lesser extent) the beam tail 130 of the focused particle beam 100 . However, the modification of the lower plane 350 is performed in a spatially separate manner from the local chemical reaction triggered by the beam tail 120 in the upper plane 340 of the steps 320 , 360 of the test structure 390 of the test element 300 . Thus, the action of the main beam 110 does not substantially affect the continued mapping of the intensity distribution of the beam tail 120 into or onto the upper plane 340 of the steps 320 , 360 .

The beam tail 130 of the focused particle beam 100 can be made visible using the left edge 330 of the step 320 with the aid of one or more precursor gases. Alternatively, the right edge 330 of the step 320 of the test structure 390 of the test element 300 can also be used to continuously map the beam tail 130 of the focused particle beam 100 .

The steps 320 , 360 of the test structure 390 of the test element 300 may facilitate spatial separation between the influence of the main beam 110 and beam tail 130 on the lower plane 350 , and the influence of the beam tail 120 on the upper plane 340 of the test structure 390 . When modifying the planar sample 140 by irradiating with the focused particle beam 100, the effect of the much higher intensity of the main beam 110 will mask the effect of the beam tails 120, 130, so the intensity distribution of the beam tails 120, 130 cannot be analyzed. Due to the incidence of the main beam 110 and the beam tails 120 , 130 on different planes along the beam propagation, the SE and BSE of the main beam 110 cannot substantially reach the detection region 340 of the beam tails 120 , 130 .

In principle, the procedure described can also be carried out in reverse. This means that the focal point 400 of the particle beam 100 is set on the lower plane 350 and the main part 110 of the particle beam 100 is directed towards the upper plane of the test structure 390 in such a way that the beam tail 120 or 130 is focused on the lower plane 350 340. However, in this embodiment, the main beam 110 produces particles in the steps 320 , 360 , some of which emerge from the steps 320 , 360 below the edge 330 and may be incident on the lower plane 350 . Therefore, some of the influence of the main beam 110 may be transferred into the area where the beam tail 120 or 130 is exposed. This makes the analysis of the intensity distribution at the beam tails 120 and 130 more difficult. Therefore, this embodiment is not preferred.

FIG. 5 presents a schematic plan view of a test element 500 with a test structure 590 . The exemplary test structure 590 of the test element 500 of FIG. 5 is applied to the base element 510 . For example, the base element can be the substrate of an optical mask into which rectangular or square depressions have been etched. However, the test structure 590 of the test device 500 may also be a contact hole of a wafer. The test structure 590 may also be created by depositing material on the base element 510 .

The exemplary test structure 590 of FIG. 5 includes a square step 520 . The step 520 has an upper plane 540 and a lower plane 550 . The lower plane 550 is the surface 570 of the base element 510 . The upper plane 540 of the step 520 has an edge 530 surrounding it, which has four right angles β in the upper plane 540 . Furthermore, the edge 530 has a right angle with respect to the lower plane 550, ie α=90°. The edge 530 of the step 520 can be used to analyze the beam tails 120, 130 of the focused particle beam 100 (similar to the illustration of FIG. 4). This means that the focal point 400 of the particle beam 100 is located in the upper plane 540 of the step 520 . With beam tails 120, 130 imaged from four different sides, the beam tail profile can be determined very accurately.

However, the number of exposures used to determine the intensity distribution of the beam tail 120, 130 is not limited to two or four. Instead, the beam tails 120, 130 may be exposed as many times as necessary to obtain as comprehensive an image as possible of the intensity distribution in the beam tails 120, 130. For this purpose, for example, the test element 300, 500 can be rotated by a defined angle around the beam axis of the focused particle beam 100. Alternatively, or in addition, the particle beam 100 may be rotated about a stationary test element 300 , 500 .

The continuous imaging of the focused particle beam 100 into the upper plane 340 , 540 of the steps 320 , 360 , 520 can be detected by scanning with a measuring probe of a scanning probe microscope (SPM), such as an atomic force microscope (AFM). Beam tail 120,130. Alternatively and/or cumulatively, the variation regions of the upper plane 340 , 540 can also be imaged by means of an optical system in order to analyze the variation of the test structures 390 , 590 of the test element 300 , 500 . In addition, the detection beam may be used to scan the variation region of the upper plane 340, 540 of the step 320, 360, 520. For example, the layout variations of the test structures 390, 590 can be analyzed by means of CLSM (Confocal Laser Scanning Microscopy). Furthermore, changes caused by chemical reactions of the test structures 390, 590 can be analyzed by means of a detection beam in the form of an electron beam, for example by scanning the variation area with electrons having different kinetic energies. Furthermore, the material composition of the deposited material can be inspected, for example, by means of a secondary ion mass spectrometer (SIMS) device.

FIG. 6 illustrates a second example embodiment for analyzing the beam tail 120 , 130 of the focused particle beam 100 . The analysis of the beam tails 120, 130 is performed based on the test structure 390 of the test element 300; however, unlike explained in the context of FIG. point, but scan parallel to edge 330. While scanning the focused particle beam 100 along the edge 330, a precursor gas adapted to vary at least the upper plane 340 of the step heights 320, 360 is provided. By scanning the particle beam 100, the area of the test structure 390 that is induced by the former is multiplied several times. In addition, the layout change of the upper plane 340 of the test structure 390 of the test device 300 caused by the combination effect of the beam tail 120 or 130 and the precursor gas can be amplified by the design of the scanning process. This simplifies the metrology detection of layout changes of the test structure 390 .

Scanning of the focused particle beam 100 along the edge 330 is indicated by the double-headed arrow 600 in FIG. 6 . As a result of scanning the focused particle beam 100 , its main beam 110 illuminates this rectangular area 610 which extends along the edge 330 or along the step 320 or the lower plane 350 of the steps 320 , 360 . When scanned along the edge 330 of the step 320 , the beam tail 120 is imaged in the focus of the lower plane 340 of the step 320 and the beam tail 120 illuminates the region 620 . In conjunction with one or more precursor gases, beam tail 120 alters region 620 of upper plane 340 of step 320 of test structure 390 as focal point 400 is scanned along edge 330 . The test structure 390 images the beam tail 130 of the focused particle beam 100 onto the lower plane 350 of the step 320 away from the focal point.

Regions 650 , 660 and 670 in FIG. 6 show the scan 600 of the focused particle beam 100 along the edge 330 of the left step 320 . These scans 600 differ in the distance of the intensity maximum I ₀ of the focused particle beam 100 from the edge 330 of the step 320 . Varying this distance allows for the best possible separation of the influence of the main beam 110 from the influence of the beam tail 120 when performing a particle beam induced etching or deposition process. To determine the intensity distribution of the beam tail 120, the variation of the region 620 of the upper plane 340 of the step 320 is analyzed.

Regions 655 , 665 and 675 in FIG. 6 show the scan 600 of the focused particle beam 100 along the edge 330 of the right step 360 . From these regions of variation 655 , 665 and 675 the intensity distribution of the beam tail 130 of the focused particle beam 100 can be determined. These scans 600 differ in the distance of the intensity maximum of the focused particle beam 100 from the edge 330 of the step 360 . Varying this distance allows for the best possible separation between the influence of the main beam 110 and the influence of the beam tail 130 when performing a particle beam induced etching or deposition process. To determine the intensity distribution of the beam tail 130, only the variation in the region 630 of the upper plane 340 of the step 360 is analyzed.

FIG. 7 presents regions 750 , 760 and 770 whose changes are detected to determine the intensity distribution of the beam tail 120 of the focused particle beam 100 . It can be seen from FIG. 7 that in addition to the areas 620 and 630 of the upper plane 340 illuminated by the beam tails 120 , 130 , the portion of the upper plane 340 not swept by the beam tails 120 , 130 when scanning the focused particle beam 100 is also measured. The measurement of the non-scanning area can be used to calibrate the measurement process. Furthermore, the variation of the irradiation area 610 produced by the main beam 110 can likewise be used for calibration purposes. For example, detection may be performed by scanning the regions 750, 760, and 770 with the measurement probe of the AFM. In order to determine the intensity distribution of the beam tail 130, changes in the surfaces 755, 765, and 775 induced by the particle beam can be detected. It goes without saying that the detection methods described above can likewise be used for this purpose.

FIG. 8 schematically presents a method for evaluating layout changes of regions 750 , 755 , 760 , 765 , 770 , 775 of the upper plane 340 of the test structure 390 caused by beam tails 120 , 130 . In this approach, the one-dimensional (1-D) contours of the regions 620, 630 are added along the edge 330 (ie, in the y-direction). The 1-D profiles are represented by dashed lines 810 , 840 and 870 in FIG. 8 . For scans 810 and 840 , portions 820 and 850 extend within variation regions 620 , 630 of upper plane 340 of test structure 390 . The variation of the test structure 390 is averaged over these portions, which is represented by the rectangle 800 in FIG. 8 . In regions 830 and 860 of scans 810 and 840 that lie outside the regions of variation 620, 630, the 1-D scans are also averaged. These averages are used as a reference to correlate the averages of the 1-D scans 820 and 850 . The averaged 1-D scan 870 then presents a further reference that extends completely outside the variation regions 620 , 630 of the structural element 390 . The intensity distribution of the beam tail 120 , 130 of the focused particle beam 100 can be reconstructed from the averaged 1-D distribution 820 , 850 . The averaged 1-D distributions 820, 850 can also be viewed as the result of a convolution operation of the edge 330 with the point spread function (PSF) of the focused particle beam 100.

FIG. 9 again shows the test element 500 having the test structure 590 shown in FIG. 5 . Focused particle beam 100 is scanned along four edges 530 of test structure 590 in a manner similar to that described for FIG. 6 . In this case, regions 950, 960, 970 and 980 are topographically altered by the combined effect of the precursor gas and the focused particle beam. Beam tails 120 , 130 of focused particle beam 100 are imaged in focus on portions 955 and 975 of illuminated areas 950 , 975 of upper plane 540 . The two beam tails 125, 135 of the focused particle beam 100 (which are perpendicular to the plane of the paper in FIG. And 985 on the scanning and imaging. Corresponding to the beam tails 120, 130, the beam tails 125, 135 of the focused particle beam 100 extending perpendicular to the paper plane may likewise be non-centrosymmetric. The beam tails 125 , 135 can also be symmetrical with respect to the intensity maximum of the main beam 110 .

Fig. 10 reproduces Fig. 9, which additionally marks the regions 1050, 1060, 1070 and 1080 where changes were detected (for example by scanning with a measuring probe of a scanning probe microscope) to determine the number of beam tails 120, 125, 130 , 135 in combination with the changes in the regions 1050, 1060, 1070, 1080 of the upper plane 540 of the test structure 590 caused by irradiation of precursor gases. As mentioned above, the regions 1050, 1060, 1070, 1080 comprise the regions 1050, 1060, 1070, 1080 which were not illuminated by the beam tails 120, 125, 130, 135 during the scan procedure along the edge. These areas 530 are used for calibration purposes. The intensity distribution of the beam tails 120, 125, 130, 135 of the focused particle beam 100 is then quantitatively determined from the measured variations of the regions 1050, 1060, 1070, 1080, as explained above in the context of Fig. 8 .

FIG. 11 presents a schematic plan view of a third example of a test element in the upper partial image, the lower partial image showing a section through said test element. The test element 1100 shown in FIG. 11 includes a base element 1110 and a test structure 1190 . The exemplary test element 1100 of FIG. 11 comprises a substrate of an optical mask (eg, a quartz substrate) as a base element 1110 . Hard mask 1120 has been applied to surface 1170 of base element 1110 . For example, hard mask 1120 may be deposited by planar deposition of a layer of chromium on quartz substrate 1110 . The thickness of the chrome layer, and thus the thickness of the hard mask 1120, may range between 1 nm and 500 nm.

Hard mask 1120 has a top side 1115 and a back side 1125 . In addition, the hard mask 1120 has an opening 1180 . The opening 1180 has an edge 1130 which surrounds the rectangular opening 1180 of the hard mask 1120 in the plane of the top side 1115 (ie, in the upper plane 1140 ). As with test elements 300 and 500 described above, it is advantageous for test element 1100 if edge 1130 forms an angle of 90° with the plane of top side 1115 and opening 1180 . The opening 1180 of the hard mask 1120 can be realized by etching the chrome layer. For example, nitrosyl chloride (NOCl) (optionally added by additive gas) can be used as the etching gas. Etching is performed through the entire thickness of the hard mask 1120 . Thus, the opening 1180 of the hard mask 1100 defines a step 1160 having an upper plane 1140 corresponding to the top side 1115 of the hard mask 1120, and a lower plane 1150 corresponding to the back side 1125 or the top side 1170 of the base member 1110).

In the upper part of the image, FIG. 12 illustrates the exposure of the test element 1100 shown in FIG. 11 with the focused particle beam 100, and the lower part of the image illustrates the exposure of the beam tail by the focused particle beam 100 when the etching gas is simultaneously supplied. 120 , 130 changes in the test element 1100 caused in the opening 1180 of the hard mask 1120 of the test element 1100 . Particle beam 100 is directed at top side 1115 of hard mask 1120 . This is depicted by the beam waist diameter 1200 in the lower portion of the image in Figure 12. If the hard mask 1120 has only a smaller depth of field than the focused particle beam 100 , the focus of the latter can be associated with the top side 1115 and the bottom side 1125 of the hard mask 1120 . Preferably, the focal point of the focused particle beam 100 is relative to the topside 1170 of the substrate 1110 such that its beam tails 120, 125, 130, 135 alter the substrate 1110 the most.

In the xy plane, ie in the plane of the paper, the focused particle beam 100 is directed at the hard mask 1120 in such a way that at least a part of the beam tail 120 , 130 falls into the opening 1180 of the hard mask 1120 . A precursor gas system in the form of an etching gas is provided simultaneously with the particle beam 100 in the region of the opening 1180 of the hard mask 1120 . For example, xenon difluoride (XeF ₂ ) may be used to etch the base element 1110 of the test element 1100 . The lower part of the image shows a recess 1250 etched into the substrate element 1110 by focusing the beam tails 120 , 130 of the particle beam 100 in combination with etching gas in the region of the opening 1180 of the hard mask 1120 .

In the upper partial image, FIG. 13 presents a plan view of a modified base element 1300 of the test element 1100 shown in FIG. 11 after hard mask 1120 has been removed. The hard mask 1120 on the variant substrate element 1300 of the test element 1100 may be removed using the etching gas NOCl, in combination with additive gases if desired. The base element 1110 has a recess 1250 in the region of the opening 1180 of the hard mask 1120 . The depression 1250 can be measured, for example, by scanning with a measuring probe of a scanning probe microscope. The obtained measurement data can be used to quantitatively determine the intensity distribution of the beam tail 120 , 130 of the focused particle beam 100 .

Analysis of the recess 1250 in the opening 1180 caused by the local etch process can also be performed without prior removal of the hard mask 1120 . This may be the case for a very thin hard mask 1120, for example. However, in the case of thick hard masks 11200, the metrology challenge is significantly greater. Furthermore, only a small area of hard mask 1120 around opening 1180 , just large enough that hard mask 1120 does not impair the measurement of recess 1250 , can be removed by etching.

FIG. 14 schematically illustrates a fourth example embodiment of a test element 1400 . The upper part of the image reproduces a plan view of the test element 1400 , and the lower part of the image reproduces a cross-section of the test element 1400 . Base element 1410 corresponds to base element 1110 of test element 1100 of FIG. 11 , which is formed from a quartz substrate of the optical mask. A hard mask 1420 has been attached to the base element 1410 . The generation, processing, and removal of the hard mask 1420 have all been described above in the context of FIGS. 11-13 . The difference between the hard mask 1420 of FIG. 14 and the hard mask 1120 is that it replaces one opening 1180 with eight openings 1480 . Eight openings 1480 of hard mask 1420 form test structures 1490 of test element 1400 . Each of the eight openings 1480 of hard mask 1420 has an edge 1430 . Compared with the single opening 1180 of the hard mask 1120 of FIG. 12, due to the larger area of the eight openings 1480 of FIG. Mask 1420 is continuously imaged into base element 1410 of test element 1400 . Similar to FIG. 12 , when the test element 1400 is illuminated, the particle beam 100 is focused on the backside 1425 of the hard mask 1420 .

Furthermore, unlike FIG. 12 , focused particle beam 100 is scanned in a vertical direction along the line of symmetry of hard mask 1420 , as indicated by double-headed arrow 1450 . Therefore, the change caused to the test element 1400 can be amplified, and the detection accuracy thereof can be improved. However, it is also possible to direct the focused particle beam 100 on the mean of the line of symmetry with fixed positioning.

The upper portion of the image of FIG. 15 shows a plan view of the modified base element 1500 of the test element 1400 after removal of the hard mask 1420, and the lower portion of the image reproduces the depressions 1510, 1520, 1530, 1540 that focus the particle beam 100. The beam tail 120 is produced in the substrate element 1410 of the test element 1400 in combination with the etching gas XeF ₂ . The indentations 1550, 1560, 1570, 1580 represent changes in the combination of the beam tail 130 of the focused particle beam 100 with the etching gas _XeF2 . The decreasing etch depth with increasing distance from the intensity maximum of the main beam 110 means that the intensity level in the beam tails 120, 130 decreases with increasing distance from the intensity peak _I0 . The intensity distribution of the beam tails 120, 130 of the focused particle beam 100 may be determined based on the obtained measurement data.

For a more precise analysis of the beam tails 125, 135 of the focused particle beam 100, the test structure 1400 may be rotated by 90° to perform a scan of the focused particle beam 100 in the horizontal direction. The intensity distribution of the beam tails 125 , 135 of the focused particle beam 100 can be determined from measurements of the variant substrate element 1300 of the test element 1100 .

By adapting the opening of the hard mask 1420 to the symmetry of the particle beam, a further improvement in measurement data can be achieved. This means that the largest part of the beam tails 120, 125, 130, 135 can be imaged into the corresponding test element through the openings in the hard mask 1420 in the form of concentric rings. However, a test element with a test structure in the form of concentric rings does not allow scanning of a focused particle beam, and thus the resulting degrees of freedom for increasing the variation of the test element 1100 cannot be made available.

In the upper partial image, FIG. 16 reproduces a plan view of a fifth test element 1600 , and the lower partial image reproduces a cross section of the test element 1600 after being irradiated by the focused particle beam 100 . The base element 1610 of the test element 1600 includes a silicon wafer. A test structure 1690 in the form of a single layer 1620 has been applied to the base element 1610 . Single layer 1620 has a top side 1615 and a back side 1625 . Monolayer 1620 may comprise a self-assembled monolayer (SAM). The self-assembled monolayer 1620 has a multilayer of molecules disposed on the surface of the base element 1610 having a thickness or a molecular layer height.

Self-assembled monolayer 1620 may comprise self-assembled organic compounds. Examples of self-assembled organic compounds are alkanethiols or alkyltrichlorosilanes. The chain length of the molecules of the monolayer and the chemical functionalization of the chains are selected such that the particle beam induces molecular changes in the monolayer through the interaction with the SE. The degree of change induced in the monolayer is proportional to the electron dose applied. For example, scanning electron microscopy can be used to visualize the induced molecular changes as changes in the SE signal. The particle beam-induced molecular changes in the monolayer are accompanied by changes in the work function of the SE of the monolayer surface. Alternatively, and/or in general, the work function of the variation can be used to detect changes in the monolayer.

The molecules of the monolayer may have functional groups such as hydroxyl, carbonyl, carboxyl, amino, or a combination of these functional groups. Presently preferred are alkanes or alkanethiols with a carbon chain length of eight (C ₈ H ₁₇ SH) to fifteen carbon atoms (C _{1 5} H ₃₁ SH). Monolayers with these chain lengths are particularly suitable for analyzing the beam tails 120 , 125 , 130 , 135 of the focused electron beam 100 . Furthermore, this can be used to analyze beam tails 120, 125, 130, 135 of photon beams from the DUV and EUV wavelength ranges of the electromagnetic spectrum.

The self-assembled layer 1620 forms spontaneously when the base member 1610 is immersed in a solution or suspension. If the base element 1610 of the test structure 1600 comprises a material that does not allow the spontaneous formation of the self-assembled monolayer 1620, the spontaneous formation of the self-assembled monolayer 1520 can be made by depositing a thin gold layer to prepare the base element 1610 (e.g., of an optical mask). quartz substrate). Furthermore, silica can be functionalized with the aid of alkyltrichlorosilanes.

The upper partial image of FIG. 16 illustrates the changes produced by the focused electron beam 100 in the self-assembled monolayer 1620 . In the center of the beam or the main beam 110, a large number of electrons incident on the self-assembled monolayer 1620 creates damage in the self-assembled monolayer 1620 by breaking molecular chains, such as alkane chains. In addition, the functional groups of the self-assembled monolayer 1620 can be chemically tuned by irradiation of the focused particle beam 100 , which is represented by dark shades 1660 in FIG. 1 . There are much fewer electrons in the region of the beam tails 120 , 125 , 130 , 135 than in the main beam 110 . However, the number of electrons in the beam tails 120, 125, 130, 135 is still significantly greater than zero. The electrons at the beam tails 120, 125, 130, 135 produce, or may appear to be, visible changes. The changes caused by the beam tails 120 , 125 , 130 , 135 are represented by gray 1670 , 1675 , 1680 , 1685 in the upper part of the image in FIG. 16 . The lower portion of the image in FIG. 16 reproduces a cross-section of the test element 1600 along the x-axis.

In a modification, the self-assembling layer 1620 adds a structure that reduces or shields the enhancement effect of the main beam 110 on the single layer 1620 . For example, the main beam 110 may be directed to a central absorbing layer, such as a metal layer, such as a chromium layer, which is surrounded by a self-combined layer 1620 on which the beam tails 120, 125, 130, 135 are incident. Alternatively or additionally, the substrate element 1610 of the test structure 1600 may have a recess into which the main beam 110 will fall, which substantially prevents the main beam 110 or the SE-modified monolayer 1620 of the main beam 110 . Furthermore, the test structure 300, 500, 1100, 1400 may be provided with a monolayer 1620 and the variation in the monolayer 1620 caused by the beam tail 120, 125, 130, 135 may be used to determine the intensity distribution of the beam tail 120, 125, 130, 135 .

When the damaged self-assembled monolayer 1630 is imaged to a scanning electron beam, the changes produced by the focused electron beam 100 in the self-assembled monolayer 1620 are sensitive to SE contrast. Localized damage to the self-assembled monolayer 1620 can be made visible by scanning the altered or damaged regions 1660, 1670, 1675, 1680, 1685 of the self-assembled monolayer 1620 with a detection beam in the form of an electron beam. The degree of local variation of the self-assembled monolayer 1620 is proportional to the beam intensity of the focused particle beam 100 locally acting on the monolayer 1620 . Thus, the intensity distribution in the beam tails 120, 125, 130, 135 can be quantitatively determined from the reconstruction of the varied monolayer.

FIG. 17 shows a schematic cross-section through some important components of an example of an apparatus 1700 that can be used to determine the intensity distribution of one or more beam tails 120 , 125 , 130 , 135 of a focused particle beam 100 . Sample 1705 (eg, in the form of an optical mask) may be disposed on sample stage 1702 . The optical mask may have one or more defects in the form of excess material ("dark defects") and/or in the form of missing material ("significant defects"). The defects of the photolithographic mask are not reproduced in Figure 17. Defects or generally defects with excess or missing material can be scanned and thus analyzed by means of a particle beam, and/or by means of a measuring probe of a scanning probe microscope 1780 . In addition, defects can be corrected by particle beam induced processing. For this purpose, apparatus 1700 includes a modified scanning particle microscope 1710 in the form of a scanning electron microscope (SEM) 1710 .

In the SEM 1710 of FIG. 17 , an electron gun 1712 generates an electron beam 1715 that is directed to a sample 1705 as a focused electron beam 1715 by an imaging element (not shown in FIG. 17 ) disposed in an electron column 1717 . The sample 1705 is arranged on the sample stage 1702 or the sample holder 1702 . The sample stage 1702 is also referred to as a "stage" in the art. As indicated by the arrows in FIG. 17 , the positioning device 1707 can move the sample stage 1702 relative to the electron column 1717 of the SEM 1710 about six axes. Movement of the sample stage 1702 by the positioning device 1707 may be performed by means of, for example, a micromanipulator (not shown in FIG. 17 ). Accordingly, localization system 1707 facilitates defect analysis of sample 1702 by generating an image of the defect. The imaging elements of electron column 1717 of SEM 1710 may scan electron beam 1715 over sample 1705 for this purpose. By tilting and/or rotating six-axis sample stage 1702, the latter can inspect one or more defects from different angles or points of view. The respective positions of the various axes of the sample stage 1702 can be measured by an interferometer (not shown in FIG. 17 ). The positioning system 1707 is controlled by signals from the setting unit 1725 . The setting unit 1735 can be a part of the computer system 1730 of the device 1700 .

Furthermore, moving the sample stage 1702 in the direction of the beam allows the sample stage 1702 to be lowered so that the test element 1725 can be positioned under the electron beam 1715 and the measurement probe of the SPM 1780 .

Apparatus 1700 may further include sensors that can characterize both the current state of SEM 1710 and the process environment in which SEM 1710 is used (eg, vacuum environment).

The electron beam 1715 may further be used to induce particle beam induced processing to correct identified defects, such as in an electron beam induced etch (EBIE) process for removing dark defects and/or an electron beam induced deposition (EBID) process for correcting apparent defects . In addition, an electron beam 1715 for analyzing the repair location of the sample 1702 may be used in the apparatus 1700 of FIG. 17 .

Device 1700 includes a holding device 1722 for holding a test element 1725 . The test element 1725 may include one of the test elements 300 , 500 , 1100 , 1400 , 160 described above. In addition, the holding device 1722 includes a positioning unit 1727 . Positioning unit 1727 facilitates positioning test element 1725 under electron beam 1715 and/or under measurement probes of SPM 1780 . Electron beam 1715 may be electron beam 100 for irradiating test element 1725 , the beam tails 120 , 125 , 130 , 135 of which are intended to be analyzed using test element 1725 . Furthermore, the electron beam 1715 may be the electron beam 100 for irradiating the test structure 1690 of the test element 1600 . Additionally, electron beam 1715 may be a detection beam for analyzing changes in test structure 1690 of test element 1600 .

Electrons backscattered from sample 1705 or test element 1725 , and secondary electrons generated by electron beam 1715 in sample 1705 or test element 1725 are recorded by detector 1720 . If the test element 1725 comprises a portion of the optical mask 110 , the detector 1720 identifies secondary electrons (SE) emitted while scanning the absorbing upper plane 340 , 540 of the test element 300 , 500 . The detector 1720 disposed in the electron column 1717 is referred to as an "in-lens detector". In various embodiments, detector 1720 may be mounted in electron column 1717 . The detector 420 is controlled by the setting unit 1735 of the computer system 1730 of the device 1700 .

The device 1700 may contain a second detector 1721 . The second detector 1721 is designed to detect electromagnetic radiation, especially in the x-ray range. Thus, second detector 1721 facilitates analysis of the material composition of both test element 1725 and sample 1705 . The detector 1721 is also controlled by the setting unit 1735 .

The setting unit 1735 of the computer system 1730 can set the parameters of the electron beam 1715 to induce the deposition process and the etching process on the test element 1725 .

In addition, the computer system 1730 of the device 1700 may include a computing unit 1740 . The calculation unit 1740 receives the measurement data of the detectors 1720 , 1721 . The computing unit 1740 may generate an image in gray scale representation or gray scale values from the measurement data (eg from SE contrast data), which may be represented on the monitor 1732 . Furthermore, the computer system 1730 includes an interface 1737, whereby the computer system 1730 or the computing unit 1740 can receive data about changes in the test element 1725 from other external detectors. Furthermore, the computer system 1730 can transmit the measurement data of the detectors 1720 and/or 1721 to an external evaluation device via an interface 1737 . Additionally, computer system 1730 of device 1700 may receive one or more processing or evaluation images, and/or one or more overlay images of test element 1725 from an external evaluation device.

As described above, the electron beam 1715 of the modified SEM 1710 of the apparatus 1700 can be used to initiate the electron beam induced process. As noted above, the test element 1725 can be permanently altered from a layout and/or chemical standpoint by EB-induced exposure. To perform these processes, the example scanning electron microscope 1710 of the apparatus 1700 shown in FIG. 17 has three different supply containers 1750 , 1760 and 1770 .

The first supply container 1750 stores a first precursor gas in the form of a deposition gas, such as a metal carbonyl, such as chromium hexacarbonyl (Cr(CO) ₆ ), or a carbon-containing precursor gas, such as pyrene, for example. With the aid of the precursor gas stored in the first supply container 1750, material can be deposited on the sample 1705 or on the test element 1725 in a localized chemical reaction, wherein the electron beam 1715 of the SEM 1710 acts as an energy supplier to convert the stored The precursor gas in the first supply container 1750 is preferably split into chromium atoms and carbon monoxide molecules at the location where the deposition material is expected (ie, on the upper plane 340, 540 of the test structure 390, 590 of the test element 1725). This means that the EBID process for permanently altering the test device 1725 is performed by the combined delivery of the electron beam 1715 and the precursor gases.

In the apparatus 1700 shown in FIG. 17, the second supply container 1760 stores the precursor gas in the form of etching gas, which makes it possible to perform a localized electron beam induced etching (EBIE) process. Recesses may be etched into the upper planes 340, 540 of the test element 1725 and/or the bottom elements 1110, 1410 of the test element 1725 with the aid of an electron beam induced etching process. Precursor gases in the form of etching gases may contain, for example, xenon difluoride (XeF ₂ ), chlorine (Cl ₂ ), oxygen (O ₂ ), ozone (O ₃ ), water vapor (H ₂ O), hydrogen peroxide (H ₂ O ₂ ), nitrous oxide (N ₂ O), nitric oxide (NO), nitrogen dioxide (NO ₂ ), nitric acid (HNO ₃ ), nitrosyl chloride (NOCl), ammonia (NH ₃ ) or hexa Sulfur fluoride (SF ₆ ) or combinations thereof.

The additive gas may be stored in the third supply container 1570 . The additive gas can be added to the etching gas kept available in the second supply container 1760 or to the deposition gas stored in the first supply container 1750 as necessary.

Alternatively, the third supply container 1770 may store the precursor gas in the form of the second deposition gas or the second etching gas.

In the scanning electron microscope 1710 shown in FIG. 17, each of the supply containers 1750, 1740 and 1770 has its own control valve 1752, 1762 and 1772 for monitoring or controlling the corresponding gas supplied per unit time. The amount of , that is, the gas volume flow rate at which the electron beam 1715 is incident on the sample 1705 or the test element 1725 . The control valves 1752 , 1762 and 1772 are controlled and monitored by the setting unit 1735 . Thereby, partial pressure conditions of one or more gases provided at a processing location for performing EBID and/or EBIE processes can be set in a wide range.

Furthermore, in the example SEM 1710 of FIG. Near the point of incidence on sample 1705 or test element 1725 .

The supply containers 1750, 1760, and 1770 may have their own temperature setting elements and/or control elements that allow cooling and heating of the respective supply containers 1750, 1760, and 1770. This makes it possible to store and in particular to provide the deposition gas and/or the etching gas precursor gases (not shown in FIG. 17 ) at respective optimal temperatures. The setting unit 1735 may control temperature setting elements and temperature control elements of the supply containers 1750 , 1760 and 1770 . During EBID and EBIE processing, the temperature setting elements of the supply vessels 1750, 1760, and 1770 may further be used to set the vapor pressure of the process gas(s) stored therein by selecting an appropriate temperature.

Apparatus 1700 may include one or more supply containers 1750 for storing precursor gases for two or more deposition gases. Additionally, the apparatus 1700 may include more than one supply container 1760 for storing precursor gases for two or more etching gases.

The scanning electron microscope 1710 shown in FIG. 17 can be operated under ambient conditions or in a vacuum chamber 1742 . Performing the EBID and EBIE processes requires a negative pressure in the vacuum chamber 1742 relative to ambient pressure. To this end, the SEM 1710 shown in FIG. 17 includes a pump system 1744 for generating and maintaining the desired negative pressure in the vacuum chamber 1742 . With the control valves 1752, 1762 and 1772 closed, a residual gas pressure of <10 ⁻⁴ Pa can be achieved in the vacuum chamber 1742 . The pump system 1744 may include separate pump systems for the upper portion of the vacuum chamber 1742 to provide the electron beam 1715 and for the lower portion 1748 or reaction chamber 1748 (not shown in FIG. 17 ).

The SEM 1710 presented in the device 1700 shown in FIG. 17 has a single electron beam 1715 . However, SEM 1710 may also have a second particle beam source. The second particle beam may comprise a photon beam and/or an ion beam (not shown in FIG. 17 ). In addition, the SEM 1710 may have two or more electron beams 1715 to be able to perform two or more particle beam induced treatment processes, or two or more measurement processes simultaneously.

Additionally, the example device 1700 shown in FIG. 17 includes a scanning probe microscope (SPM) 1780 embodied in the device 1700 as a scanning force microscope (SFM) 1780 or an atomic force microscope (AFM) 480 . SPM 1780 may be used to scan for permanently mutated test elements 1725 . Additionally, SPM 1780 can be used to repair sample 1705. To this end, SPM 1780 may include a first measurement probe for analyzing test element 1725 and/or sample 1706 and a second measurement probe for processing sample 1705 .

Only the measurement head 1785 of the SPM 1780 is shown in the apparatus 1700 of FIG. 17 . In the example of FIG. 17 , the measuring head 1785 includes a holding unit 1787 . The measuring head 1785 is fastened to the frame of the device 1700 by means of a holding unit 1787 (not shown in FIG. 17 ). A piezoelectric actuator 1790 is attached to the holding unit 1787 of the measuring head 1785, which enables the free end of the piezoelectric actuator to move in three spatial directions (not shown in Figure 17). Probe 1795 or measurement probe 1795 includes a cantilever 1794 or lever arm 1794 and a measurement tip 1792 is fixed to the free end of piezoelectric actuator 1790 . The free end of the cantilever 1794 of the measurement probe 1795 has a measurement tip 1792 . The SPM 1780 thus implements a measurement unit 1780 designed to measure variations of the test element 1725, more specifically layout variations.

The setting unit 1735 of the computer system 1730 can move the holding unit 1787 of the measuring head 1785 of the AFM 1780 . The setting unit 1735 can further perform rough positioning of the sample 1705 or test element 1725 in height (z direction), and the precise height setting of the AFM 1780 for the piezoelectric actuator 1790 of the measuring head 1785 .

In apparatus 1700 , SPM 1780 may be used instead or in addition to scan sample 1705 . Apparatus 1700 may use two or more SPMs 1780 . The SPMs 1780 may be of the same type, or may be implemented as different types of SPMs.

In the example shown in FIG. 17 , SPM 1780 is integrated into device 1700 and controlled by computer system 1730 of device 1700 . SPM 1780 may also be embodied as a stand-alone unit (not shown in Figure 17).

The computing unit 1740 of the computer system 1730 of the device 1700 may have an algorithm designed to determine the intensity distribution of the beam tails 120 , 125 , 130 , 135 of the focused particle beam 1715 from the measurement data of the SPM 1780 . Algorithms can be implemented in hardware, software, firmware or a combination thereof.

Finally, the flowchart 1800 of FIG. 18 summarizes again the basic steps of the described method for determining the intensity distribution of one or more beam tails 120 , 125 , 130 , 135 of the focused particle beam 100 . The method starts at step 1810 . In a next step 1820, the test element 300, 500, 1100, 1400, 1600 is irradiated with the focused particle beam 100 such that at least one tail 120, 125, 130, 135 of the focused particle beam 100 causes the test element 300, 500, 1100, 1400, 1600 measurable changes 620, 955, 1250, 1540.

In step 1830 , the variation 620 , 955 , 1250 , 1540 of the test element 300 , 500 , 1100 , 1400 , 1600 is measured to determine the intensity distribution of at least one tail 120 , 125 , 130 , 135 of the focused particle beam 100 . The method ends at step 1840 .

A number of further examples are described below to aid in the understanding of the invention. 1. A method (1800) for determining the intensity distribution of at least one tail (120, 125, 130, 135) of a focused particle beam (100), the method (1800) comprising the steps of: a. irradiating (1820) a test element (300, 500, 1100, 1400, 1600) with the focused particle beam (100) such that the at least one tail (120, 125, 130, 135) causing at least one measurable change (620, 955, 1250, 1540, 1670) of the test element (300, 500, 1100, 1400, 1600); and b. measuring (1830) the at least one change (620, 955, 1250, 1540, 1670) of the test element (300, 500, 1100, 1400, 1600) to determine the at least one change of the focused particle beam (100) Intensity distribution of beam tails (120, 125, 130, 135). 2. The method (1800) of embodiment 1, wherein the illumination of the test element (300, 500, 1100, 1400, 1600) causes at least one layout of the test element (300, 500, 1100, 1400, 1600) A change (620, 955, 1250, 1540), at least one chemical change (1660, 1670, 1675, 1680, 1685), and/or at least one physical change (300, 500, 1100, 1400, 1600). 3. The method (1800) of embodiment 1 or 2, wherein the test element (300, 500, 1100, 1400, 1600) comprises at least one test structure (390, 590, 1190, 1490, 1690), the test The structure contains at least one element from the following groups: - At least one high order (320, 360, 520); - at least one hard mask (1120, 1420) having at least one opening (1180, 1480); and - At least one single storey (1620). 4. The method (1800) of embodiment 3, wherein the at least one step (320, 360, 520) and/or the at least one opening (1180, 1480) has at least one edge (330, 530, 1130, 1430), and/or wherein the monolayer (1620) is designed to alter secondary electron contrast when irradiated with the focused particle beam (100). 5. The method (1800) of embodiment 3 or 4, further comprising: setting the height (380) of the at least one step height (320, 360, 520) and/or the hard mask (1120, 1420) thickness such that the beam area of the focused particle beam (100) increases by at least 2%, preferably 5%, or more along the height (380) relative to the beam waist diameter (400) of the focused particle beam (100) The best is 10%, and the best is 30%. 6. The method (1800) of embodiments 3 to 5, wherein irradiating the test element (300, 500, 1100, 1400, 1600) comprises: focusing the particle beam (100) on at least one element of the following group : - an upper plane (340, 540) of the at least one step (320, 360, 520), and/or a rear side (1125) of the hard mask (1120, 1420); - a lower plane (350, 550) of the at least one step height (320, 360, 520), and/or a top side (1115) of the hard mask (1120, 1140); - a top side (1620) of the single layer (1620). 7. The method (1800) of embodiments 3 to 6, wherein irradiating the test element (300, 500, 1100, 1400, 1600) comprises at least one element of the following group: - irradiating at least one point of the lower plane (350, 550) of the at least one step height (320, 360, 520) with the focused particle beam (100), such that the at least one beam tail (120, 125, 130, 135) is incident an upper plane (350, 550) on the at least one step (320, 360, 520); - scanning the focused particle beam (100) along at least one edge (330, 530, 1130, 1430) of the at least one step height (320, 360, 520) such that the at least one beam of the focused particle beam (100) the tail (120, 125, 130, 135) is incident on the upper plane (350, 550) of the at least one height (320, 360, 520); - illuminating at least one point of the hard mask (1120, 1420) with the focused particle beam (100) such that at least a portion of the at least one beam tail (120, 125, 130, 135) is incident on the hard mask (1120, the at least one opening (1180, 1480) in 1420); - scanning the focused particle beam (100) parallel to the at least one edge (330, 530, 1130, 1430) of the at least one opening (1180, 1480) of the hard mask (1120, 1420) such that the at least one beam at least a portion of the tail (120, 125, 130, 135) is incident on the at least one opening (1180, 1480) in the hard mask (1120, 1140); - irradiating at least one point of the monolayer (1620). 8. The method (1800) of embodiments 3 to 7, wherein irradiating the test element (300, 500, 1100, 1400, 1600) comprises at least one element of the following group: - selecting a distance between an intensity maximum of the focused particle beam (100) and the at least one edge (330, 530, 1130, 1430) of the at least one height (320, 360, 520) such that the focused Particles generated by the particle beam (100) in the lower plane (350, 550) of the at least one height (320, 350, 520) substantially do not reach the upper plane of the at least one height (320, 260, 520) surface(350, 550); - selecting a difference between the intensity maximum of the focused particle beam (100) and the at least one edge (330, 530, 1130, 1430) of the at least one opening (1180, 1480) in the hard mask (1120, 1420) a distance between such that particles generated by the focused particle beam (110) in the hard mask (1120, 1420) substantially do not reach the at least one opening (1180, 1480); - selecting the energy of the focused particle beam (100) such that substantially none of the particles of the focused particle beam (100) reach a rear side (1625) of the monolayer (1620). 9. The method (1800) of any one of the embodiments, wherein illuminating the test element (300, 500, 1100, 1400, 1600) comprises: the At least one edge (330, 530, 1130, 1430) at an intensity maximum of the focused particle beam (100) and the at least one edge (330, 530, 1130, 1130, The focused particle beam (100) is scanned in at least two different distances between 1430). 10. The method (1800) of any one of embodiments 1 to 9, wherein irradiating the test element (300, 500, 1100, 1400, 1600) comprises: at the at least one of the focused particle beams (100) At least one precursor gas is provided in the region of the beam tail (120, 125, 130, 135). 11. The method (1800) of embodiment 10, wherein the at least one precursor gas comprises at least one element from the group: at least one etching gas, at least one deposition gas, and at least one additive gas. 12. The method (1800) of any one of embodiments 1 to 11, wherein measuring the at least one change of the test element (300, 500, 1100, 1400, 1600) comprises at least one element of the following group: - scanning the test element covered by at least the at least one tail (120, 125, 130, 135) of the focused particle beam (100) using a measuring probe (1795) of a scanning probe microscope (1780) Area (620, 955) of (300, 500, 1100, 1400, 1600); - scanning (520) the area (520) of the test element (300, 1100, 1400, 1600) covered at least by the at least one tail (120, 125, 130, 135) of the focused particle beam (100) with a detection beam , 955), and analyzing particles produced by the detection beam; - using an optical system to image at least the area of the test element (300, 500, 1100, 1400, 1600) covered by the at least one tail (120, 125, 130, 135) of the focused particle beam (100) ( 620, 955); - preparing the area (620, 955, 1250) of the test element (300, 500, 1100, 1400, 1600) covered by the at least one tail (120, 125, 130, 135) of the focused particle beam (100) , 1540), and image the prepared portion of the test element (300, 500, 1100, 1400, 1600) using an electron beam of a transmission electron microscope. 13. The method (1800) of any one of embodiments 1 to 12, wherein measuring the at least one change (620, 955) of the test structure (300, 500, 1100, 1400, 1600) comprises: using a A detection beam scans at least the region of the monolayer (1620) covered by the beam tail (120, 125, 130, 135) of the focused particle beam (100), and detects at least Secondary electron contrast in the coverage area. 14. The method (1800) of any one of embodiments 1 to 13, wherein the at least one monolayer (1620) comprises a self-assembled organic compound. 15. The method (1800) of embodiment 14, wherein the test element (300, 500, 1100, 1400, 1600) comprises at least one layer made of at least one element of the following group: gold (Au), silver (Ag), platinum (Pt), copper (Cu), graphite (C) and silicon (Si). 16. A computer program containing a plurality of instructions, when a computer system executes the computer program, it causes the computer system to execute the method steps described in any one of embodiments 1-16. 17. A device (1700) for determining an intensity distribution of at least one tail (120, 125, 130, 135) of a focused particle beam (100), comprising: a. a setting unit (1735), configured to set at least one parameter of the focused particle beam (100), such that when a test element (300, 500, 1100, 1400, 1600) is irradiated by the focused particle beam (100), , the focused particle beam (100) causes at least one measurable change (620, 955, 1250, 1540, 1670) of the test element (300, 500, 1100, 1400, 1600); and b. a measurement unit (1780) configured to measure the at least one change (620, 955, 1250, 1540, 1670) of the test element (300, 500, 1100, 1400, 1600) to determine the focused particle beam ( The intensity variation of the at least one bundle tail (120, 125, 130, 135) of 100). 18. The device (1700) of embodiment 17, further comprising a holding device (1722) for the test element (300, 500, 1100, 1400, 1600). 19. The device (1700) of embodiment 18, wherein the holding device (1722) comprises a positioning unit (1727) configured to position the test element (300, 500, 1100, 1400, 1600) on the focusing particle Below the beam (100) and/or below the measuring unit (1780). 20. The device (1700) according to any one of embodiments 17 to 19, further comprising a computing unit (1740) configured to extract from the A measurement variation (620, 955, 1250, 1540, 1670) determines an intensity distribution of the at least one tail (120, 125, 130, 135) of the focused particle beam (100).

100: Focused Particle Beam 110: main beam 120, 125, 130, 135: beam tail 140: sample 150: pixels 160, 170, 180, 200, 210, 220, 230, 240, 610, 650, 655, 660, 665, 670, 675, 750, 755, 760, 765, 770, 775, 830, 860, 950, 960, 970, 980, 1050, 1060, 1070, 1080, 1660, 1670, 1675, 1680, 1685: area 190: maximum intensity 300, 500, 1400, 1600: test element 310, 510, 1110, 1300, 1410, 1500, 1610: base element 320, 360: pattern element/step height 330, 530, 1130, 1430: Edge 340, 540: upper plane 350, 550, 1150: lower plane 370, 570: surface 380: height 390, 590, 1190, 1490, 1690: test structure 400, 1200: waist diameter 520, 1160: step height 620, 630: Variation area 800: rectangle 810, 840: dotted line/scan 820, 850: partial/1-D distribution 870: dotted line 955, 965, 975, 985: part 1115, 1170, 1615: top side 1120, 1420: hard mask 1125, 1425, 1625: dorsal side 1140: hard mask 1250: sunken 1450: Two-way arrow 1480: opening 1510, 1520, 1530, 1540, 1550, 1560, 1570, 1580: Depression 1620: single layer 1700: Installation 1702: sample table 1705: sample 1707: positioning system 1710: Scanning Electron Microscope (SEM) 1712: Electron gun 1715: electron beam 1717: Electron column 1720: detector 1721: detector 1722: holding device 1725: Test element 1727: positioning unit 1730: Computer systems 1732: Monitor 1735: setting unit 1737: interface 1740: computing unit 1742: Vacuum chamber 1744: Pump system 1748: Lower part/reaction chamber 1750: Supply Containers 1752: Control valve 1754: Gas supply pipeline system 1756: Nozzle 1760: Supply Containers 1762: Control valve 1764: Gas supply pipeline system 1766: nozzle 1770: Supply Containers 1772: Control valve 1774: Gas supply pipeline system 1776: nozzle 1780: Scanning force microscope (SFM) 1785: measuring head 1787: Holding unit 1790: Piezoelectric actuators 1792: Measuring tip 1794: Cantilever / Lever Arm 1795: Measuring Probes

The following description will describe presently preferred example embodiments of the invention with reference to the drawings, in which:

Figure 1a illustrates a schematic cross-section of the beam profile of a focused particle beam with two different beam tails;

Figure 1b reproduces the plan view of the sample irradiated by the focused particle beam in Figure 1a;

Figure 2 schematically represents an area irradiated with a focused particle beam having a non-centrosymmetric beam tail;

Figure 3 reproduces in the upper partial image a schematic plan view of a test element with a test structure comprising two pattern elements of an optical mask, and in the lower partial image a section through the test element through the upper partial image ;

Fig. 4 depicts in the upper part of the image that a focused particle beam with a beam tail is used to irradiate the test element of Fig. 3, and in the lower part illustrates that the focal position of the particle beam is associated with the test structure of the test element of Fig. 3;

Figure 5 shows a schematic plan view of a second example of a test structure of a test element;

Fig. 6 schematically depicts that the focused particle beam of Fig. 1 is scanned along the edge of the step of the test element in Fig. 3, wherein the distance between the intensity maxima of the focused particle beam and the distance from the edge of the step are changed;

FIG. 7 reproduces FIG. 6 with additionally labeled regions of measurement layout changes to determine the beam tail of the focused particle beam;

FIG. 8 reproduces FIG. 7 with the additional depiction of determining the one-dimensional profile to calculate the beam profile of the beam tail;

Fig. 9 schematically presents that the focused particle beam of Fig. 1 scans along the four edges of the test structure of the test element of Fig. 5;

FIG. 10 repeats FIG. 9 , with additionally marked regions for measuring layout changes caused by the combined effect of the beam tail and at least one precursor gas to determine the beam tail intensity distribution of the focused particle beam of FIG. 1 ;

FIG. 11 shows a schematic plan view of a third example of a test element in the upper partial image and a section thereof in the lower partial image, wherein the test structure of the test element comprises a substrate element on which is deposited a hard mask for

Figure 12 illustrates in the upper part of the image the irradiation of the test structure of the test element of Figure 11 with the focused particle beam of Figure 1, and the lower part of the image illustrates the layout of the test element caused by the combined effect of the beam tail and etching gas Variety;

Figure 13 reproduces the plan view of the variant base element of the test element of Figure 11 after removal of the hard mask in the upper part of the image, and presents the plan view of the variant base component after removal of the hard mask in the lower part of the image profile;

FIG. 14 reproduces in the upper partial image a schematic plan view of a fourth example of a test element with a test structure having a hard mask with eight openings arranged symmetrically along the longitudinal axis, and the test element by means of Irradiation is performed by scanning a focused particle beam in the y-direction, and a section through the test element is shown in the lower part of the image;

Figure 15 reproduces the plan view of the modified base element of the test element of Figure 14 after removal of the hard mask in the upper part of the image, and presents a plan view of the modified base part after removal of the hard mask in the lower part of the image profile;

FIG. 16 reproduces in the upper partial image a schematic plan view of a fifth example of a test element in the form of a self-assembled monolayer after irradiation with the focused particle beam of FIG. a profile of the test element and the focused particle beam;

Figure 17 reproduces a schematic cross-section through several components of a device that facilitates irradiating a test element with the tail of a focused particle beam, or with a focused particle beam and a precursor gas, and that allows the measurement of induced changes in the measuring element; and

Figure 18 shows a flow diagram of a method for determining the intensity distribution of the beam tail of a focused particle beam.

100: Focused Particle Beam

120: beam tail

130: beam tail

200: area

300: test components

310: base element

320: pattern element/step height

330: edge

340: upper plane

350: lower plane

360: pattern element/step height

370: surface

380: height

390: Test structure

400: waist diameter

Claims (43)

A method for determining an intensity distribution of a particle beam on a sample, the method comprising the steps of: a. irradiating a test element with the particle beam such that the particle beam causes at least one measurable change in the test element; and b. measuring the at least one change of the test element to determine the intensity distribution of the particle beam on the sample. The method of claim 1, wherein the particle beam is a focused particle beam, and determining the intensity distribution comprises: by irradiating (1820) the test element (300, 500, 1100, 1400, 1600) such that at least one tail (120, 125, 130, 135) of the focused particle beam (100) causes at least one measurable change (600, 955, 1250, 1540, 1670) to determine an intensity distribution of the at least one tail of the focused particle beam; and measure (1830) the at least one change ( 600, 955, 1250, 1540, 1670) to determine the intensity distribution of the at least one tail (120, 125, 130, 135) of the focused particle beam (100). The method of claim 1, wherein the particle beam irradiates the sample through at least one precursor gas, and determining the intensity distribution comprises determining a change in the intensity distribution caused by the at least one precursor gas on the sample. The method of any one of claims 1 to 3, wherein the particle beam irradiates the sample through a shielding element, and determining the intensity distribution comprises determining a change in the intensity distribution caused by the shielding element on the sample. The method of claim 4, wherein the shielding element performs at least one of: redistributing a plurality of scattered beam particles passing through the shielding element in a beam direction and generating a plurality of secondary particles. A method for determining a spontaneous etch rate and/or a spontaneous deposition rate of at least one precursor gas used in a particle beam induced etching process and/or in a particle beam induced deposition process of a sample, the The method includes the following steps: a. providing the at least one precursor gas to a test element at a predetermined gas flow rate for a predetermined period of time without irradiating the test element with a particle beam; and b. measuring the at least one change of the test element to determine the spontaneous etch rate and/or the spontaneous deposition rate of the at least one precursor gas on the sample. The method of claim 6, further comprising changing at least one of: the gas flow rate, a composition of the at least one precursor gas, and a temperature of the at least one precursor gas; and repeating step a. The method according to any one of claims 1 to 7, wherein the test element comprises a base element and at least one structural element, wherein the at least one structural element is preferably disposed on the base element. The method of the preceding claims, wherein the structural element comprises a first material and the base element comprises a second material, wherein the first material is different from the second material. The method as described in the preceding claims, wherein the difference between a spontaneous etch rate of the first material induced by the at least one precursor gas and a spontaneous etch rate of the second material of the test sample is at least 2 times, preferably At least 5 times, more preferably at least 10 times, and most preferably at least 20 times. The method according to any one of claims 1 to 10, wherein the at least one structural element comprises at least one of the following: a checkerboard pattern, an aperture mask having at least one opening, at least one cylinder, and a random structure. The method of the preceding claims, wherein the randomized structure comprises gold particles on a carbon layer. The method according to any one of claims 1 to 12, wherein measuring the at least one change of the test element comprises at least one of the following: measuring a change of an edge of the test element and measuring a change of the test element A change between regions. The method (1800) of any one of claims 1 to 5 or 8 to 13 with direct or indirect re-reference to claim 1, wherein the irradiation of the test element (300, 500, 1100, 1400, 1600) causes at least one layout change (620, 955, 1250, 1540), at least one chemical change (1660, 1670, 1675, 1680, 1685), and/or at least one Physical changes (300, 500, 1100, 1400, 1600). The method (1800) of any one of claims 1 to 14, wherein the test element (300, 500, 1100, 1400, 1600) has at least one test structure (390, 590, 1190, 1490, 1690), It contains at least one element from the following groups: - At least one high order (320, 360, 520); - at least one hard mask (1120, 1420) having at least one opening (1180, 1480); and - At least one single storey (1620). The method (1800) of the preceding claim, wherein the at least one step (320, 360, 520) and/or the at least one opening (1180, 1480) has at least one edge (330, 530, 1130, 1430) , and/or wherein the monolayer (1620) is designed to alter secondary electron contrast when irradiated with the focused particle beam (100). The method (1800) of claim 15 or 16, further comprising: setting a height (380) of the at least one step height (320, 360, 520) and/or a height of the hard mask (1120, 1420) a thickness such that a beam area of the focused particle beam (100) increases along the height (380) by at least 2%, preferably 5% relative to the beam waist diameter (400) of the focused particle beam (100) , more preferably 10%, and best 30%. The method (1800) of any one of claims 15 to 17, wherein irradiating the test element (300, 500, 1100, 1400, 1600) comprises: focusing the particle beam (100) on at least one of the following groups On the component: - an upper plane (340, 540) of the at least one step (320, 360, 520), and/or a rear side (1125) of the hard mask (1120, 1420); - a lower plane (350, 550) of the at least one step height (320, 360, 520), and/or a top side (1115) of the hard mask (1120, 1140); - a top side (1620) of the single layer (1620). The method (1800) of any one of claims 15 to 18, wherein irradiating the test element (300, 500, 1100, 1400, 1600) comprises at least one element of the following group: - irradiating at least one point of the lower plane (350, 550) of the at least one step height (320, 360, 520) with the focused particle beam (100), such that the at least one beam tail (120, 125, 130, 135) is incident an upper plane (350, 550) on the at least one step (320, 360, 520); - scanning the focused particle beam (100) along at least one edge (330, 530, 1130, 1430) of the at least one step height (320, 360, 520) such that the at least one beam of the focused particle beam (100) the tail (120, 125, 130, 135) is incident on the upper plane (350, 550) of the at least one height (320, 360, 520); - illuminating at least one point of the hard mask (1120, 1420) with the focused particle beam (100) such that at least a portion of the at least one beam tail (120, 125, 130, 135) is incident on the hard mask (1120, the at least one opening (1180, 1480) in 1420); - scanning the focused particle beam (100) parallel to the at least one edge (330, 530, 1130, 1430) of the at least one opening (1180, 1480) in the hard mask (1120, 1420) such that the at least one at least a portion of the beam tail (120, 125, 130, 135) is incident on the at least one opening (1180, 1480) in the hard mask (1120, 1140); - irradiating at least one point of the monolayer (1620). The method (1800) of any one of claims 15 to 19, wherein irradiating the test element (300, 500, 1100, 1400, 1600) comprises at least one element of the following group: - selecting a distance between an intensity maximum of the focused particle beam (100) and the at least one edge (330, 530, 1130, 1430) of the at least one height (320, 360, 520) such that the focused Particles generated by the particle beam (100) in the lower plane (350, 550) of the at least one height (320, 350, 520) have substantially no access to the at least one height (320, 260, 520) the upper surface (350, 550); - selecting a difference between the intensity maximum of the focused particle beam (100) and the at least one edge (330, 530, 1130, 1430) of the at least one opening (1180, 1480) in the hard mask (1120, 1420) a distance between such that particles generated by the focused particle beam (110) in the hard mask (1120, 1420) substantially do not reach the at least one opening (1180, 1480); - selecting an energy of the focused particle beam (100) such that substantially none of the particles of the focused particle beam (100) reach a rear side (1625) of the monolayer (1620). The method (1800) of any one of claims 15 to 20, wherein illuminating the test element (300, 500, 1100, 1400, 1600) comprises: the at least An edge (330, 530, 1130, 1430) at an intensity maximum of the focused particle beam (100) and the at least one edge (330, 530, 1130, 1430) of the at least two steps high (320, 360, 530) The focused particle beam (100) is scanned in at least two different distances between ). Claim 2, or the method (1800) of any one of claims 3 to 5 or claims 8 to 11 with direct or indirect re-reference to claim 2, wherein the test element is irradiated (300, 500 , 1100, 1400, 1600) comprising at least one of: providing at least one precursor gas in a region of the particle beam, and the at least one tail (120, 125, 130) of the focused particle beam (100) , 135) providing at least one precursor gas in a region. The method (1800) of the preceding claim, wherein the at least one precursor gas comprises at least one member of the following group: at least one etching gas, at least one deposition gas, and at least one additive gas. The method (1800) of any one of claims 1 to 23, wherein measuring the at least one change in the test element (300, 500, 1100, 1400, 1600) comprises at least one element of the following group: - scanning at least the area of the test element covered by the particle beam using a measuring probe (1795) of a scanning probe microscope (1780); - scanning the test element covered by at least the at least one tail (120, 125, 130, 135) of the focused particle beam (100) using a measuring probe (1795) of a scanning probe microscope (1780) (300, 500, 1100, 1400, 1600) of the area (620, 955); - scanning at least the area of the test element covered by the particle beam with a detection beam and analyzing the particles generated by the detection beam; - scanning at least the area of the test element (300, 1100, 1400, 1600) covered by the at least one tail (120, 125, 130, 135) of the focused particle beam (100) with a detection beam ( 520, 955), and analyzing the particles produced by the detection beam; - imaging at least the area of the test element covered by the particle beam using an optical system; - imaging at least the area of the test element (300, 500, 1100, 1400, 1600) covered by the at least one tail (120, 125, 130, 135) of the focused particle beam (100) using an optical system (620, 955); - preparing the area ( 620, 955, 1250, 1540), and image the prepared portion of the test element (300, 500, 1100, 1400, 1600) using an electron beam of a transmission electron microscope. The method according to any one of claims 1 to 24, wherein measuring the at least one change of the test element comprises at least one element of the following group: - using a measuring probe of a scanning probe microscope (1780) (2795) scan 0.01cm 2 , preferably 0.1cm ² , more preferably 1cm ² , ^and most preferably an area of 5 cm ² ; - scan 0.01 cm 2 , preferably 0.1 cm ² of the test element covered by 2x2, preferably 5x5, more preferably 10x10, most preferably 20x20 measuring points using a detection beam cm ² , preferably 1 cm ² , and optimally 5 cm ² ; - use an optical system to image the test covered by 2x2, preferably 5x5, more preferably 10x10, optimally 20x20 measurement points An area of 0.01 cm ² , preferably 0.1 cm ² , more preferably 1 cm ² , and most preferably 5 cm ² of the element. The method (1800) of any one of claims 1 to 25, wherein measuring the at least one change (620, 955) of the test structure (300, 500, 1100, 1400, 1600) comprises: using a detection radiometer beam scanning the monolayer (1620) covered by at least one of the particle beam, the beam tail (120, 125, 130, 135) of the focused particle beam (100), and the at least one precursor gas region, and detecting secondary electron contrast at least in the region covered. Claims 15 to 20, or the method (1800) of any one of claims 21 to 26 with direct or indirect reference back to claim 15, wherein the at least one monolayer (1620) comprises a self-assembled organic compound. The method (1800) of the preceding claim, wherein the test element (300, 500, 1100, 1400, 1600) comprises at least one layer comprising at least one element of the following group: gold (Au), silver (Ag), platinum (Pt), copper (Cu), graphite (C) and silicon (Si). The method of any one of claims 8 to 10, or any one of claims 11 to 28 with direct or indirect re-reference to claim 8, wherein the substrate element is adapted so that a particle beam induced etching process is not substantially The base element of the test structure is etched, and the at least one structural element of the test structure includes at least one pillar to be etched in the particle beam induced etching process. Claims 8 to 10, or the method of any one of claims 11 to 29 with direct or indirect re-reference to claim 8, wherein the structural element comprises at least two columns adapted such that a particle The beam-induced etching process does not substantially etch the at least two pillars, and the base element includes a material to be etched during the particle beam-induced etching process. The method of any one of claims 8 to 10, or any one of claims 11 to 29 with direct or indirect re-reference to claim 8, wherein the at least one structural element comprises at least one aperture mask adapted to A particle beam induced etching process does not substantially etch the at least one aperture mask, and the substrate element is adapted such that the particle beam induced etching process etches the substrate element. The method of the preceding claim, wherein the aperture mask comprises at least two openings for determining a change of the base element. A computer program containing a plurality of instructions, when a computer system executes the computer program, the instructions cause the computer system to execute the method steps as described in any one of Claims 1-32. A device for determining an intensity distribution of a particle beam on a sample comprising: a. an irradiating member for irradiating a test element with the particle beam such that the particle beam causes at least one measurable change in the test element; and b. A measuring means for measuring the at least one variable means of the test element to determine the intensity distribution of the particle beam on the sample. The device as claimed in claim 34, further comprising a focusing member for focusing the particle beam. The device as claimed in claim 34 or 35, further comprising a providing member for providing at least one precursor gas on the sample and/or the test element. The device as claimed in claim 36, wherein the providing means for providing the at least one precursor gas comprises a setting means for setting a gas flow rate of the at least one precursor gas. The device according to any one of claims 34 to 37, further comprising a measuring member for measuring the at least one change of the test element. The device according to any one of claims 34 to 38, further comprising a determining means for determining the intensity distribution of the particle beam from the at least one measured change of the test element. A device (1700) for determining an intensity distribution of at least one tail (120, 125, 130, 135) of a focused particle beam (100), comprising: a. a setting unit (1735), configured to set at least one parameter of the focused particle beam (100), such that when a test element (300, 500, 1100, 1400, 1600) is irradiated by the focused particle beam (100), , the focused particle beam (100) causes at least one measurable change (620, 955, 1250, 1540, 1670) of the test element (300, 500, 1100, 1400, 1600); and b. a measurement unit (1780) configured to measure the at least one change (620, 955, 1250, 1540, 1670) of the test element (300, 500, 1100, 1400, 1600) to determine the focused particle beam ( 100) of the intensity distribution of the at least one beam tail (120, 125, 130, 135). The device (1700) of the preceding claim, further comprising a holding device (1722) for the test element (300, 500, 1100, 1400, 1600). The device (1700) of the preceding claim, wherein the holding device (1722) comprises a positioning unit (1727) configured to position the test element (300, 500, 1100, 1400, 1600) on the focusing particle Below the beam (100) and/or below the measuring unit (1780). The device (1700) of any one of claims 40 to 42, further comprising a calculation unit (1740) configured to vary from the measurement of the test element (300, 500, 1100, 1400, 1600) (620, 955, 1250, 1540, 1670) determining the intensity distribution of the at least one tail (120, 125, 130, 135) of the focused particle beam (100).

Images