Apparatus and method for verifying components, and lithography system

Abstract

Apparatus and methods for inspecting components, as well as lithography systems, are provided. The present invention relates to an apparatus (1) for inspecting a component (2) comprising a periodic structure (3) having substructures (5) arranged on a grid (4), the apparatus (1) comprising at least a measuring radiation source (6) for generating measuring radiation (7), an optical system (8), and a camera device (9). A phase mask device (10) for influencing the phase angle of the measuring radiation (7) is provided, the phase mask device (10) having a dual grid (11) opposite to the target shape of the grid (4).

Description

[Technical Field]

[0001] This application claims priority to German Patent Application No. DE102023203731.9, filed on 24 April 2023, which is incorporated in its entirety by reference and forms part of this disclosure.

[0002] The present invention relates to an apparatus for verifying a component having a periodic structure having substructures arranged on a grid, and comprising at least a measuring radiation source for generating measuring radiation, an optical system, and a camera device.

[0003] The present invention also relates to a method for identifying a component having a periodic structure having substructures arranged on a grid, wherein at least one measuring radiation source for generating measuring radiation, an optical system, and a camera device are used.

[0004] Furthermore, the present invention relates to a lithography system, particularly a projection exposure apparatus for producing semiconductor components, comprising an illumination system equipped with a radiation source and an optical unit equipped with at least one optical element. [Background technology]

[0005] Prior art has disclosed methods for forming semiconductor components by etching and / or coating.

[0006] Prior art has also disclosed the formation of 3D NAND memory chips by etching and / or coating periodically arranged through-holes or through-vias. In this context, vias are often implemented in deep double-layer stacks, particularly in multiple double-layer stacks or so-called bilayer stacks.

[0007] Typically, such semiconductor components require verification, measurement, and / or suitability assessment to check for defects.

[0008] The prior art disclosed non-destructive and destructive methods for verifying semiconductor components.

[0009] As non-destructive methods, tomography, ptychography, or coherent diffraction imaging (CDI) using X-ray light are known from prior art.

[0010] However, the drawbacks of non-destructive methods, as known from conventional technologies, are their complexity of implementation, the low throughput they can achieve, and the slow inspection speeds they allow.

[0011] For example, known destructive methods from the prior art include scanning electron microscopy (FIB-SEM) using a focused ion beam. [Overview of the project]

[0012] The present invention aims to develop a device for verifying components that avoids the shortcomings of the prior art and enables efficient and highly reliable verification of periodic structures in particular.

[0013] According to the present invention, this objective is achieved by an apparatus having the features specified in claim 1.

[0014] The present invention aims to develop a device for verifying components that avoids the shortcomings of the prior art and enables efficient and highly reliable verification of periodic structures in particular.

[0015] According to the present invention, this objective is achieved by a method having the features specified in claim 16.

[0016] The present invention is based on the object of developing a lithography system that avoids the disadvantages of the prior art and enables the production of semiconductor components in a particularly efficient and highly reliable manner.

[0017] According to the present invention, this object is achieved by a lithography system having the features specified in claim 27.

[0018] The device according to the present invention serves to inspect a component having a periodic structure with sub-structures arranged on a grid, and comprises at least one measurement radiation source for generating measurement radiation, at least one optical system, and at least one camera device. According to the present invention, a phase mask device for influencing the phase angle of the measurement radiation is provided, which has a reciprocal dual grid that is reciprocal to the target shape of the grid.

[0019] The device according to the present invention enables the inspection of components at a high throughput or high inspection speed, and the device according to the present invention can be used particularly within a production line.

[0020] Compared to inspection methods based on the comparison of conventional intensity images known from the prior art, the device according to the present invention has excellent accuracy. As a result, the device according to the present invention is suitable for the high-speed and sufficiently high-precision inspection of components within a production line, or for in-line inspection.

[0021] The device according to the present invention enables a direct interferometric comparison between the position of each individual sub-structure and its target position. This enables the direct and simultaneous detection of amplitude shift and phase shift, in contrast to the comparison based on intensity images captured using a conventional microscope objective. In particular, the conventional microscope resolution limit Δx according to equation (1) can be avoided as a result.

[0022]

Equation

[0023] Preferably, the apparatus according to the present invention can be configured to superimpose the diffraction pattern of a lattice with the diffraction pattern of a corresponding dual lattice or reciprocal dual lattice (these lattices are preferably substantially point-like lattices).

[0024] The dual grating can be arranged such that the diffraction pattern of the grating and the dual grating are superimposed within the imaging pupil. Furthermore, the zeroth order of diffraction of the dual grating can be provided to have the same efficiency as the complementary order contributing to the entire image.

[0025] The light source can be provided so as to be configured to obtain Köhler-type illumination of the component.

[0026] In one advantageous evolution of the apparatus according to the present invention, the phase mask device may have dual substructures arranged on a dual grid.

[0027] Preferably, the dual substructure corresponds to the target shape of the substructure being inspected.

[0028] In one advantageous evolution of the apparatus according to the present invention, the dual substructure can be provided to be at least substantially circular.

[0029] In particular, when inspecting or measuring vias that often have a circular target cross-section, and where the substructure being inspected also has a circular target cross-section, it is advantageous if the dual substructure also has a circular cross-section.

[0030] In one advantageous evolution of the apparatus according to the present invention, the phase mask device can be provided such that, at a distance from the dual substructure, it provides a phase offset of the measured radiation by half a wavelength compared to the complementary portion of the dual substructure on the phase mask device.

[0031] The phase mask device provides a phase offset of the measured radiation by half a wavelength relative to the complementary portion of the dual substructure, away from the dual substructure, and in one preferred configuration where the dual substructure is at least substantially circular, it is formed as a binary λ / 2 phase aperture mask with carriers as the dual lattice, as expressed in equation (2) χ G* A phase mask device is generated, given by this.

[0032]

number

[0033] In equation (2), χ K :={k≦ε} represents a circle with radius ε. Furthermore, the operator * is the symbolic representation of mathematical convolution.

[0034] Therefore, G * *χ K This realizes the ε-neighborhood of the dual lattice. In equation (2), the dual lattice is G * This can be expressed as follows. The ε-neighborhood can also be called a hole.

[0035] Here, the phase mask device is the case where ε(k) = 0. In addition to the phase mask device, an amplitude mask device having a non-zero ε(k) according to equation (2) can also be provided, which is used to reduce the transmission of measurement radiation on the phase mask device in a region away from the dual substructure or in the complementary portion of the dual substructure. In this case, ε(k) ≥ 0 represents the actual absorption coefficient in the complementary portion of the dual substructure.

[0036] In one advantageous evolution of the apparatus according to the present invention, the optical system can be provided to include at least one Fourier device for performing an optical Fourier transform on the measured radiation.

[0037] By using a Fourier device to perform the optical Fourier transform, the diffraction pattern of a grating can be superimposed onto its dual grating, particularly easily.

[0038] In one advantageous evolution of the apparatus according to the present invention, a placement device can be provided and configured to accommodate components such that a periodic structure is positioned within the object plane of a Fourier device.

[0039] When the apparatus is configured such that the components are arranged so that the periodic structure is located within the object plane of the Fourier device, the optical Fourier transform can be performed with particularly high reliability and accuracy.

[0040] The object plane is preferably positioned perpendicular to the optical axis of the optical system and / or Fourier device.

[0041] In particular, the object plane can be advantageously positioned within the focal plane of the Fourier device, preferably the front focal plane of the Fourier device, or coincide with the focal plane of the Fourier device, preferably the front focal plane of the Fourier device.

[0042] For this reason, it is particularly advantageous if a placement device is provided and configured to accommodate the components.

[0043] In one advantageous evolution of the apparatus according to the present invention, the phase mask device can be provided such that it is positioned within the pupil plane of the Fourier device opposite to the object plane.

[0044] Placing the phase mask device within the pupil plane of the Fourier device enables particularly reliable superposition of the diffraction pattern of the grating undergoing the optical Fourier transform by the Fourier device with that of the dual grating on the phase mask device. Preferably, the phase mask device is placed within the imaging pupil of the Fourier device.

[0045] In an advantageous evolution of the apparatus according to the present invention, the Fourier device can be provided to include a lens having a first numerical aperture for viewing the entire periodic structure perpendicular to the object plane, or a second numerical aperture for viewing only the cross-sectional region of the periodic structure parallel to the object plane.

[0046] In particular, the first numerical aperture can be preferably smaller than the second numerical aperture.

[0047] When a small numerical aperture or a large depth of field is used, it is possible to detect all shifts in the periodic structure of the components, either along the optical axis or along the depth of the periodic components, in a simultaneously averaged manner. Depth of field Δ Z This can be given by equation (3).

[0048]

number

[0049] In equation (3), λ represents the wavelength of the measured radiation, and NA represents the numerical aperture of a Fourier device equipped with a microscope objective lens.

[0050] In contrast, when a very large numerical aperture or a small depth of field is used (see equation (3)), it is possible to analyze a cross-section of the component at a certain depth along the optical axis.

[0051] The apparatus according to the present invention can be provided configured to scan a component at a depth z of the component. The depth z can be oriented in particular along the optical axis. By scanning at a depth z, it is possible to determine the positional displacement and / or other displacements as a function of the depth z by interferometry.

[0052] A Fourier device can be provided configured to operate in a first operating mode having a first numerical aperture, and in a second operating mode having a second numerical aperture, such that the first and second operating modes do not exist simultaneously.

[0053] In one advantageous evolution of the apparatus according to the present invention, the Fourier device can be provided to include an aperture diaphragm configured to set the numerical aperture of the Fourier device.

[0054] The aperture diaphragm allows for easy switching between the first and second operating modes.

[0055] Setting the numerical aperture or depth of field, which can be associated according to equation (3), is particularly simple and reliable by adapting the aperture diameter of the Fourier device.

[0056] In this case, it is particularly advantageous if the lens of the Fourier device is designed as a high NA lens. By reducing the aperture diameter, it is possible to reduce the large initial NA of the lens, thereby increasing the depth of field.

[0057] In one advantageous evolution of the apparatus according to the present invention, a holding device can be provided and configured to displace the phase mask device within the pupil plane, preferably in both spatial directions of the pupil plane.

[0058] By displacing the phase mask device within the pupil plane, it is possible to minimize the influence of optical aberrations on the measurement results of component verification.

[0059] Similar to the phase shift method known from interferometry, a portion of the aberration can be "removed by calibration" by displacing the phase mask device. In addition, this makes it possible to determine the interference phase of the measured radiation with greater precision.

[0060] In one advantageous evolution of the apparatus according to the present invention, the phase mask device can be provided such that it is formed by an etched structuring of a half-wavelength coating on a transmittive or transmissive substrate.

[0061] When the phase mask is fabricated by an etched structure of a λ / 2 coating on a transparent substrate, this makes it possible to form both the phase mask device and a constant absorption effect ε≧0 in the complementary portion of the dual substructure of the phase mask device according to equation (2) in a particularly simple and reliable manner.

[0062] In particular, the transparent substrate can be provided as part of the optical system and / or optical design of the apparatus according to the present invention.

[0063] The phase mask device can be formed from permeable or slightly absorbing glass having a structured thickness. Preferably, the thickness of the glass is given by χ in formula (2). G* It is proportional to the phase effect of the phase mask device given by the process. The depth change required for this can be achieved, in particular, by the etching process.

[0064] Alternatively, or in addition to the above, the phase mask device can be provided as being formed by a mirror with a height structuring. In this case, the height structuring of the mirror is preferably the phase effect χ according to equation (2). G* It is proportional to.

[0065] In embodiments using glass with a depth structure, and in embodiments using mirrors with a height structure, the path difference of the measured radiation between the dual substructure and their complementary portions on the phase mask device is half a wavelength or λ / 2 optical path length.

[0066] Preferably, it is provided such that the aberration caused by the phase mask device or the substrate is compensated by the optical system, particularly by the Fourier device, and very particularly by the lens of the Fourier device.

[0067] Alternatively or in addition thereto, it can be provided that a laser is used to form or drill holes having an optical path length of λ / 2 in the glass substrate.

[0068] In an advantageous development of the device according to the invention, the phase mask device can be provided to be digitally operable and / or transmissive and / or reflective, and / or as a microelectromechanical system, and / or as a spatial light modulator (SLM), particularly as a liquid crystal on silicon SLM (LCOS - SLM), and / or as a spatial light phase modulator.

[0069] For example, when a digitally operable, transmissive, or reflective phase mask device based on MEMS (microelectromechanical systems) is used, within the spatial resolution of the MEMS, any desired phase effect, or any desired dual grating or G * pattern can also be set.

[0070] In an advantageous development of the device according to the invention, it can be provided that an imaging device is provided for imaging the measurement radiation onto the camera device.

[0071] The imaging device enables a highly reliable imaging of the measurement radiation carrying information about the component onto the camera device, preferably in a second Fourier step. In particular, this can ensure a high image quality that enables a preferably digital analysis of the resulting interferogram.

[0072] In an advantageous development of the device according to the invention, it can be provided that the Fourier device comprises a zoom optical unit.

[0073] Using a zoom optical unit makes it possible to change the pupil size of the Fourier device, and therefore the illumination area of ​​the phase mask device. For example, as a result, the dual lattice G * It can be scaled.

[0074] In addition to the zoom optical unit, a dual grid or G * Substantially any desired pattern for a pattern can preferably be set using digitally operable and / or transmissive and / or reflective phase mask devices, as well as phase mask devices designed as microelectromechanical systems and / or spatial light modulators, particularly as liquid crystal on silicon SLMs and / or spatial light phase modulators.

[0075] In one advantageous evolution of the apparatus according to the present invention, the measuring radiation source can be configured to generate measuring radiation of various wavelengths and / or the measuring radiation can be provided to be infrared radiation.

[0076] Various wavelengths are appropriately scaled dual gratings or G * When used with patterns, it is possible to improve measurement and / or detection accuracy.

[0077] Dual lattice or G * Pattern scaling can be performed here by the zoom lens described above and / or by changing the phase mask device.

[0078] Dual lattice G of a phase mask device * The above configuration is particularly suitable for the purpose of inspecting NAND memory chips, or more generally, for inspecting G-periodic structures.

[0079] Furthermore, if the lens preferably uses infrared light, the component can be penetrated to its depth by the measurement radiation. In particular, NAND stacks can be penetrated to their depth in this way by the measurement radiation.

[0080] Conventional techniques have proposed methods for comparing substructures in pairs using differential interference contrast microscopy (DIC microscopy). Compared to the apparatus according to the present invention, such methods are disadvantageous in that they do not provide a good standard when individual substructures, particularly vias, may be strictly deviated from the target shape but are nevertheless not critical to production. However, the DIC signal does not convey information about how critical the measured large relative deviation is to actual production. Such problems are avoided by the apparatus according to the present invention.

[0081] Therefore, the apparatus according to the present invention is particularly suitable for verifying whether a manufactured via is free of defects in three dimensions, and for determining the suitability of a via and / or measuring it.

[0082] In one advantageous evolution of the apparatus according to the present invention, the dual lattice can be provided such that it is designed as the inverse of the one-dimensional and / or two-dimensional target shapes of the lattice.

[0083] The apparatus is particularly advantageous when used to measure one-dimensional and / or two-dimensional grids.

[0084] To measure a two-dimensional lattice, the dual lattice also preferably has a two-dimensional, particularly extended, form.

[0085] To measure a one-dimensional lattice, the dual lattice also preferably has a one-dimensional, particularly linear, form.

[0086] The present invention also relates to a method for verifying a component having the features specified in claim 17.

[0087] A method according to the present invention for identifying a component having a periodic structure with substructures arranged on a grid uses at least one measurement radiation source for generating measurement radiation, at least one optical system, and at least one camera device. According to the present invention, the displacement of each substructure from a reference substructure is provided to be determined by interferometry.

[0088] In the method according to the present invention, the displacement of the periodic structure from the target structure is determined by interferometry. In this case, the shape of each substructure and their positions on the grid are considered to be a complex-valued optical mask.

[0089] The method according to the present invention is advantageous in that, in contrast to the averaging of intensity images from conventional microscope objective lenses, it enables direct detection of amplitude and phase shifts through direct comparison using interferometry, and therefore avoids the conventional resolution limit.

[0090] In the method according to the present invention, the diffraction pattern of a lattice and the diffraction pattern of a corresponding dual lattice or reciprocal dual lattice (these lattices are preferably substantially point-like lattices) can be superimposed on each other.

[0091] In one advantageous evolution of the method according to the present invention, the reference substructure can be provided such that it is determined by periodic averaging of the periodic structure.

[0092] An interferogram formed from an object, i.e., a component or grid, and a reference substructure in which the reference substructure is produced by periodic averaging, can be measured in particular as an intensity image in the form given by equation (4).

[0093]

number

[0094] In equation (4), G represents a grid on which substructures are arranged at its grid points, or G can be called a grid consisting of substructure locations.

[0095] The grid can have one-dimensional and / or two-dimensional forms.

[0096] x represents the location in object space, β represents the imaging scale of the optical system, and c represents a complex constant that is preferably close to the reciprocal of the number of grid points, so that the reference substructure approximately represents the periodic averaging.

[0097] In one advantageous evolution of the method according to the present invention, periodic averaging can be provided to be performed by superimposing the diffraction pattern of the periodic structure with a phase mask device.

[0098] Particularly advantageous is that periodic averaging is used with the dual lattice G * This can be produced by the superposition of diffraction patterns (which are said to be dual to or, in crystallographic terms, reciprocal to lattice G).

[0099] An alternative method for recording the interference pattern I(x) according to equation (4) may be to generate a reference image and a test image separately, and then coherently superimpose the reference image and the test image.

[0100] In one advantageous evolution of the method according to the present invention, the phase angle of the measurement radiation within a dual substructure, preferably a circular dual substructure, on a dual grid opposed to the target shape of the grid, is offset by half a wavelength of the measurement radiation compared to the complementary portion of the dual substructure on the phase mask device, thereby enabling the measurement radiation to be affected by the phase mask device.

[0101] In this case, the phase mask device acts on the measured radiation in the style of a binary λ / 2 phase aperture mask, where dual substructures are arranged on carriers represented by the dual lattice G*.

[0102] It is advantageous if the zero-order diffraction of the phase mask device has a diffraction efficiency similar to the sum of the higher-order diffraction orders that are imaged, so that the images of the object and the reference, i.e., the components represented by the two augmentants of equation (4), and the image of the phase mask device have similar intensities, at least on average over location x. For this purpose, the complementary portion of the perforated mask or the complementary portion of the dual substructure on the phase mask device can have an absorption coefficient ε(k) ≥ 0 according to equation 2.

[0103] In this case, the region of the phase mask device away from the dual substructure, i.e., the complementary portion of the dual substructure, acts at least approximately as a conventional pupil, optically generating the first term of equation (4) except for the location-constant phase, while the reference image or the image of the phase mask device given by the second term of equation (4) is generated by the grating made up of the dual substructure except for the constant phase.

[0104] The intensity pattern of the measured radiation on the camera device can be determined by superimposing the diffraction pattern of the periodic structure with a phase mask device, and then imaging the measured radiation onto the camera device by an imaging device.

[0105] In one advantageous evolution of the method according to the present invention, the focal length of the Fourier device can be provided to be varied by a zoom optical unit.

[0106] This makes it possible to realize dual lattices G* for various object lattice structures, or for various lattices G, without changing the phase mask device or phase aperture mask.

[0107] Furthermore, a zoom optical unit can perform slight wavelength adaptations, provided that the phase offset within the phase mask device or phase aperture mask remains within at least approximately half a wavelength of the measured radiation.

[0108] When the aforementioned λ / 2 phase aperture mask is imaged onto the camera device, the intensity image given by equation (4) is generated on the camera device and becomes measurable by the camera device. This facilitates the digital analysis of the intensity distribution. On the camera device, the intensity distribution is generated as the square of the norm of the complex linear map S given by equation (5), which takes into account diffraction at the pupil rim, but excludes scaling.

[0109]

number

[0110] In equation (5) shown above, χ G* This represents a perforated mask or phase mask device according to equation (2). According to equation (5), the periodic structure of the component is given as a complex-valued optical mask оbj. F f This represents the Fourier transform operator for the focal length f, which is given by equation (5a).

[0111]

number

[0112] In equation (5a), the vector is the 2D x within the parallelized region of the measured radiation. k The spatial coordinates are shown. The physical pupil coordinate k, which represents the beam direction of the measured radiation and is normalized to 2π / λ, is expressed by equation (5b).

[0113]

number

[0114] Therefore, as a function of k, F f obj is the conventional Fourier transform of оbj.

[0115] The characteristic function of the pupil limiting aperture is given by equation (6).

[0116]

number

[0117] Furthermore, f' represents the focal length of the second Fourier step, particularly the effect of the imaging device, and as a result, the mapping S is the imaging scale.

[0118]

number

[0119] The characteristic function described above for limiting the pupil represents a low-pass filter in this case. The characteristic function for limiting the pupil is the signal of the measured radiation and the amplitude point spreading function F. -1 χ NA This can be expressed as a convolution. Such convolutions, in particular, take the form of an Airy disk and are observable especially as signal blurring.

[0120] However, the phase information within the difference signal of the measured radiation is advantageously retained a priori within the intensity signal given by equation (5).

[0121] The intensity distribution given by equation (5) can be further rewritten mathematically, thereby approximately deriving the formula given by equation (7).

[0122]

number

[0123] In equation (7), t and t' represent positive constants in x, which are determined in particular by the diameter of the dual substructure and the absorption coefficient of the phase mask device in the complementary part of the dual substructure. Furthermore, δ G* is the dual lattice G * This represents the Dirac delta function with respect to the carriers. The expression given in equation (7) can be approximately rewritten using Fourier's theorem as the expression given in equation (8).

[0124]

number

[0125] Next, the expression given by equation (8) can be rewritten as a representation of the mapping S given by equation (9). In this case, the expressions on the right-hand sides of equations (8) and (9) are mathematically identical.

[0126]

number

[0127] Therefore, the square of the norm of S approximates the interferogram according to the present invention, given by equation (4).

[0128] Similar to the phase shift known from interferometry, a portion of the aberration can be "removed by calibration" by further displacing the phase mask device. Furthermore, partial calibration of the aberration, and thus more accurate determination of the interference phase of the measured radiation, becomes possible. The phase of the measured radiation at t'(ε) in the difference signal S (see equations (7) to (9)) changes due to the offset of the phase mask device.

[0129] Advantageously, the Fourier device can be provided to include a neutral density filter, preferably one located within the pupil plane.

[0130] Particularly preferably, the light-reducing filter has the shape of a Gaussian profile according to equation (10).

[0131]

number

[0132] In equation (10), NA 2 Gauss This represents the numerical aperture under the assumption of a Gaussian distribution.

[0133] The expression F can be achieved by a neutral density filter designed according to equation (10). -1 χ NA The signal itself follows a Gaussian distribution, specifically a positive real number, which means that the interference signal of the measured radiation is simply Gaussian averaged rather than being phase-modulated by the attenuation filter.

[0134] Alternatively, the attenuation filter can be directly integrated into a phase aperture mask or phase mask device using the absorption coefficient ε(k) of equation (2).

[0135] In one advantageous evolution of the method according to the present invention, the diffraction pattern of a periodic structure and the phase mask device can be superimposed within the pupil plane of the Fourier device.

[0136] The Fourier device can preferably be designed as a Fourier lens. For example, the Fourier device can be designed as a reflecting / refracting lens element, as is known from, for example, U.S. Patent No. 7,639,419B2, particularly from Figure 16 therein, and / or as part of a lithography lens, as is known from, for example, U.S. Patent Application Publication No. 2018 / 0031815, particularly from Figure 1 therein.

[0137] It is advantageous if the Fourier device is provided in a manner optimized for aberrations. In particular, it is advantageous if the Fourier device has a very slight phase gradient so as to avoid distortion and thus a mismatch between the phase mask device and the periodic structure.

[0138] In this case, the aberration shown in equation (5) occurs as a result of the following equation being applicable, and this aberration may cause slight phase modulation.

[0139]

number

[0140] In one advantageous evolution of the method according to the present invention, multiple interferograms can be recorded such that the phase mask device is displaced to a different location within the pupil plane for each interferogram.

[0141] Some of the aberrations mentioned above can be removed by calibration through phase shifting. As a result of the offset of the perforated mask, the phase of t'(ε) in the difference signal S can be changed according to equation (9), thereby enabling more accurate determination of the interference phase in a manner similar to phase shifting in interferometry.

[0142] In one advantageous evolution of the method according to the present invention, various wavelengths of measurement radiation can be used, preferably such that the dual grating is scaled according to the wavelength of measurement radiation used.

[0143] By changing the wavelength, the measurement accuracy can be further improved.

[0144] In one advantageous evolution of the method according to the present invention, the scaling of the dual lattice is - Resulting from changes in the phase mask device, and / or - A Fourier device preferably equipped with a zoom optical unit changes the pupil size and / or the illumination area of ​​the phase mask device, resulting in It can be provided in this way.

[0145] The dual grating can be scaled in a particularly simple and reliable manner by changing the phase mask device and / or altering the focal length of the Fourier device.

[0146] The zoom optical unit allows the optical properties of the Fourier device to change particularly rapidly, thereby increasing the throughput of this method.

[0147] In one advantageous evolution of the method according to the present invention, a component can be provided to be further verified using a method for measuring optical limit dimensions, in which its intensity distribution is simulated with the help of a parameterized model of the component.

[0148] In addition to the above-described variations, the method according to the present invention can also be combined with a method for measuring optical limit dimensions (OCD method). In the OCD method, the expected mapping S according to equation (9) is simulated with the help of a parameterized model of its components. In this process, the parameters of the parameterized model are optimized to fit the measurement results, i.e., the actual measured mapping S according to equation (9).

[0149] As a result, accuracy in parameter reconstruction of the parameterized model is obtained, and this accuracy can be advantageously enhanced a priori by including phase information of the measured radiation according to the present invention.

[0150] In one advantageous evolution of the method according to the present invention, a NAND memory chip having periodically arranged vias can be provided as a component.

[0151] This method is particularly suitable for verifying memory chips (NAND memory chips) equipped with NOT-AND logic gates. Particularly advantageous, vias periodically arranged within such NAND memory chips, as periodic structures, can be verified reliably and quickly using the method according to the present invention.

[0152] A parameterized model of a NAND memory chip is advantageous if it is simulated within the range of combination with the OCD method.

[0153] The method according to the present invention can be provided in combination with the differential interference contrast microscopy method.

[0154] A differential interference contrast microscopy method for measuring components is described, for example, in DE102018217115A1. The method according to DE102018217115A1 may be particularly suitable for carrying out a mixed form with the method according to the present invention.

[0155] In one advantageous evolution of the method according to the present invention, the dual lattice can be provided such that it is designed as the inverse of the one-dimensional and / or two-dimensional target shapes of the lattice.

[0156] The present invention further relates to a lithography system having the features specified in claim 29.

[0157] A lithography system according to the present invention, particularly a projection exposure apparatus for producing semiconductor components, comprises an illumination system with a radiation source and an optical unit with at least one optical element. According to the present invention, the above-described apparatus according to the present invention is provided for inspecting components, particularly semiconductor components. Alternatively or in addition thereto, the lithography system is provided to be configured to perform the method according to the present invention for inspecting components, particularly semiconductor components.

[0158] Therefore, an apparatus according to the present invention for verifying components is provided within a lithography system according to the present invention, as part of the lithography system, and is preferably configured to verify semiconductor components produced by the lithography system. Alternatively or in addition, the lithography system is configured to perform the above-described method according to the present invention for verifying components, and the lithography system is preferably configured to perform the method according to the present invention for verifying semiconductor components produced by the lithography system.

[0159] In the lithography system according to the present invention, an apparatus for inspecting semiconductor components can be provided such that it is spatially separated from the location where the semiconductor components are exposed, and / or a method for inspecting semiconductor components produced by the lithography system can be provided such that it is performed spatially separated from the location where the semiconductor components are exposed.

[0160] As a result of integrated quality control, the lithography system according to the present invention enables the efficient and highly reliable production of high-quality semiconductor components. In this case, the method and apparatus according to the present invention are used to verify the components currently provided by the semiconductor components to be produced.

[0161] In one advantageous evolution of the lithography system according to the present invention, the lithography system can be provided to be configured to produce and verify semiconductor components designed as NAND memory chips having periodically arranged vias.

[0162] Generally speaking, it is advantageous if the lithography system according to the present invention is configured to produce structures imaged on a wafer and to verify these structures in relation to any possible shape defects.

[0163] The components identified in accordance with the present invention are preferably semiconductor components, particularly a lithography system or semiconductor components produced by the lithography system. Preferably, the semiconductor component is a NAND memory chip.

[0164] Specifically, features described in relation to one of the subjects of the present invention, provided by the apparatus, method, or lithography system according to the present invention, are also advantageously implementable for the other subjects of the present invention. Similarly, advantages expressed in relation to one of the subjects of the present invention can also be understood in relation to the other subjects of the present invention.

[0165] In addition, note that terms such as “to have,” “to possess,” or “equipped” do not exclude other features or steps. Furthermore, words such as “a(n)” or “the” that indicate individual steps or features do not exclude multiple features or steps, and vice versa.

[0166] However, in pure embodiments of the present invention, features introduced to the invention using the terms “equipped with,” “having,” or “equipped with” may also be provided in an exhaustive enumeration. Thus, one or more enumerations of features can be considered exhaustive within the scope of the invention, for example, by considering each claim individually. For example, the present invention may consist solely of the features specified in claim 1.

[0167] Please note that notations such as "first" or "second" are used primarily to distinguish between different device features or method features, and that these notations do not necessarily indicate that the features are mutually dependent on or related to each other.

[0168] Furthermore, it is disclosed at this point that the interferometer apparatus and / or method according to the present invention are suitable for measuring the surface of any desired element. For example, the surface may be the surface of a component from the automotive industry. In this regard, the applicant reserves the right to file a divisional application in which the feature “optical element” is replaced with the feature “element”.

[0169] Exemplary embodiments of the present invention will be described in detail below with reference to the drawings.

[0170] Each figure illustrates a preferred exemplary embodiment in which individual features of the present invention are combined with one another. Features of the exemplary embodiments can also be implemented independently of other features of the same exemplary embodiment and, accordingly, can be readily combined by those skilled in the art to form further viable combinations and partial combinations with features of other exemplary embodiments.

[0171] In the diagram, functionally identical elements are given the same reference numeral. [Brief explanation of the drawing]

[0172] [Figure 1] This figure shows a meridional cross-section of an EUV projection lithography system. [Figure 2] This is a diagram showing a DUV projection exposure apparatus. [Figure 3] This is a schematic diagram of a possible embodiment of the apparatus according to the present invention for verifying components. [Figure 4] This is a schematic diagram of one possible embodiment of a phase mask device. [Figure 5] This is a block diagram-type figure of one possible embodiment of a method according to the present invention for verifying components. [Figure 6] This is a schematic diagram of one possible embodiment of the confirmed NAND memory chip. [Modes for carrying out the invention]

[0173] Regarding Figure 1, the essential components of the microlithography EUV projection exposure apparatus 100, as an example of a lithography system, will be described below illustratively. The description of the basic structure of the EUV projection exposure apparatus 100 and its components should not be interpreted restrictively here.

[0174] The illumination system 101 of the EUV projection exposure apparatus 100 includes, in addition to the radiation source 102, an illumination optical unit 103 for illuminating the object field of view 104 within the object surface 105. The object being exposed is a reticle 106 positioned within the object field of view 104. The reticle 106 is held by a reticle holder 107. The reticle holder 107 is displaceable, particularly in the scanning direction, by a reticle displacement drive 108.

[0175] Figure 1 shows a Cartesian xyz coordinate system plotted to aid in the explanation. The x-direction extends perpendicularly within the plane of the drawing. The y-direction extends horizontally, and the z-direction extends vertically. In Figure 1, the scan direction extends along the y-direction. The z-direction extends perpendicularly to the object plane 105.

[0176] The EUV projection exposure apparatus 100 includes a projection optical unit 109. The projection optical unit 109 functions to image the object field of view 104 into the image field of view 110 within the image plane 111. The image plane 111 extends parallel to the object plane 105. Alternatively, an angle other than 0° is possible between the object plane 105 and the image plane 111.

[0177] The structure on the reticle 106 is imaged onto the photosensitive layer of the wafer 112, which is positioned within the image field 110 of the image plane 111. The wafer 112 is held by a wafer holder 113. The wafer holder 113 can be displaced by a wafer displacement drive 114, particularly along the y-direction. The displacement of the reticle 106 by the reticle displacement drive 108 and the displacement of the wafer 112 by the wafer displacement drive 114 can be synchronized with each other.

[0178] Radiation source 102 is an EUV radiation source. Radiation source 102 emits EUV radiation 115, also referred to below as work radiation or illumination radiation. In particular, work radiation 115 has wavelengths in the range of 5 nm to 30 nm. Radiation source 102 can be a plasma source, for example, an LPP source ("laser-generated plasma") or a GDPP source ("gas discharge-generated plasma"). Radiation source 102 can also be a synchrotron-based radiation source. Radiation source 102 can be a free electron laser (FEL).

[0179] Illumination radiation 115 emanating from the radiation source 102 is focused by a collector 116. The collector 116 may be a collector having one or more elliptical and / or hyperbolic reflecting surfaces. At least one reflecting surface of the collector 116 can be struck by the illumination radiation 115 at grazing incidence (GI), i.e., at an incidence angle greater than 45°, or at normal incidence (NI), i.e., at an incidence angle less than 45°. The collector 116 may be structured and / or coated to first optimize its reflectivity to the radiation used 115, and second to suppress external light.

[0180] Downstream of the collector 116, the illumination radiation 115 propagates through the intermediate focus within the intermediate focal plane 117. The intermediate focal plane 117 can represent the separation of the radiation source module, which has the radiation source 102 and collector 116, from the illumination optical unit 103.

[0181] The illumination optical unit 103 comprises a deflection mirror 118 and a first facet mirror 119 downstream of it in the beam path. The deflection mirror 118 may be a planar deflection mirror or a mirror that has a beam influence effect beyond a simple deflection effect. Alternatively or in addition, the deflection mirror 118 may be designed as a spectral filter that separates the wavelength of light used by the illumination radiation 115 from external light of different wavelengths. When the first facet mirror 119 is positioned in the plane of the illumination optical unit 103, which is optically conjugate to the object plane 105 as a field of view, the first facet mirror 119 is also called a field of view facet mirror. The first facet mirror 119 comprises a plurality of individual first facets 120, also called field of view facets below. Only a few of these facets 120 are shown illustratively in Figure 1.

[0182] The first facet 120 can be realized in the form of a macroscopic facet, particularly in the form of a rectangular facet, or in the form of a facet with an arched peripheral contour or a peripheral contour of part of a circle. The first facet 120 can also be realized as a planar facet, or as a convex or concave curved facet.

[0183] For example, as is known from DE102008009600A1, each of the first facets 120 itself can be composed of a number of individual mirrors, particularly a number of micromirrors. In particular, the first facet mirror 119 can take the form of a micro-electromechanical system (MEMS system). For further details, please refer to DE102008009600A1.

[0184] The illumination radiation 115 travels horizontally, i.e., along the y-direction, between the collector 116 and the deflection mirror 118.

[0185] Within the beam path of the illumination optical unit 103, the second facet mirror 121 is positioned downstream of the first facet mirror 119. The second facet mirror 121 is also called a pupil facet mirror, provided that it is positioned within the pupil plane of the illumination optical unit 103. The second facet mirror 121 can also be positioned away from the pupil plane of the illumination optical unit 103. In this case, the combination of the first facet mirror 119 and the second facet mirror 121 is also called a specular reflector. Specular reflectors are known from U.S. Patent Application Publication No. 2006 / 0132747, EP1614008B1, and U.S. Patent No. 6,573,978.

[0186] The second facet mirror 121 comprises multiple second facets 122. In the case of a pupil facet mirror, the second facets 122 are also called pupil facets.

[0187] Similarly, the second facet 122 can be a macroscopic facet that has, for example, a circular, rectangular, or hexagonal perimeter, or it can be a facet composed of micromirrors. In this regard, please refer to DE102008009600A1.

[0188] The second facet 122 may have a planar reflective surface, or it may have a curved reflective surface that is convex or concave.

[0189] The illumination optical unit 103 consequently forms a doubly faceted system. This basic principle is also known as a fly-eye integrator.

[0190] It may be advantageous not to strictly position the second facet mirror 121 within a plane that is optically conjugate to the pupil plane of the projection optical unit 109.

[0191] With the help of the second facet mirror 121, each individual first facet 120 is imaged within the object field of view 104. The second facet mirror 121 is the final beam shaping mirror, or rather, the very last mirror for the illumination radiation 115, in the beam path upstream of the object field of view 104.

[0192] In a further embodiment of the illumination optical unit 103 (not shown), a transfer optical unit may be positioned in the beam path between the second facet mirror 121 and the object field of view 104, and the transfer optical unit contributes, in particular, to imaging the first facet 120 into the object field of view 104. The transfer optical unit may have exactly one mirror, or it may have two or more mirrors arranged in succession in the beam path of the illumination optical unit 103. In particular, the transfer optical unit may comprise one or more mirrors for direct incidence (NI mirrors, i.e., “direct incidence” mirrors) and / or one or more mirrors for oblique incidence (GI mirrors, i.e., “oblique incidence” mirrors).

[0193] In the embodiment shown in Figure 1, the illumination optical unit 103 comprises exactly three mirrors downstream of the collector 116, specifically a deflection mirror 118, a field of view facet mirror 119, and a pupil facet mirror 121.

[0194] In a further embodiment of the illumination optical unit 103, the deflection mirror 118 may be omitted, and therefore the illumination optical unit 103 may have exactly two mirrors downstream of the collector 116, specifically a first facet mirror 119 and a second facet mirror 121.

[0195] Image formation of the first facet 120 onto the object plane 105 using the second facet 122, or using the second facet 122 and the transmission optics unit, is usually only an approximate image.

[0196] The projection optical unit 109 comprises a plurality of mirrors Mi numbered according to their arrangement within the beam path of the EUV projection exposure apparatus 100.

[0197] In the example shown in Figure 1, the projection optical unit 109 comprises six mirrors M1 to M6. Alternative configurations with four, eight, ten, twelve, or any other number of mirrors Mi are equally possible. The second-to-last mirror M5 and the last mirror M6 each have through-apers for illumination radiation 115. The projection optical unit 109 is a doubly obscured optical unit. The projection optical unit 109 has an image-side numerical aperture, which may be greater than 0.5 and greater than 0.6, for example, 0.7 or 0.75.

[0198] The reflective surface of mirror Mi can take the form of a free-form surface without an axis of rotational symmetry. Alternatively, the reflective surface of mirror Mi can be designed as an aspherical surface with exactly one axis of rotational symmetry of the reflective surface shape. Just like the mirror of illumination optical unit 103, mirror Mi can also have a coating that is highly reflective to the illumination radiation 115. These coatings can take the form of a multilayer coating, in particular, with alternating layers of molybdenum and silicon.

[0199] The projection optical unit 109 has a large object image offset in the y-direction between the y-coordinate of the center of the object field of view 104 and the y-coordinate of the center of the image field of view 110. In the y-direction, this object image offset can be approximately the same in magnitude as the z-distance between the object plane 105 and the image plane 111.

[0200] The projection optical unit 109 can, in particular, have an anamorphic form. Specifically, the projection optical unit 109 has different imaging scales βx and βy in the x and y directions. The two imaging scales βx and βy of the projection optical unit 109 are preferably (βx, βy) = (+ / -0.25, + / -0.125). A positive imaging scale β means imaging without image inversion. A negative sign of the imaging scale β means imaging with image inversion.

[0201] The projection optics unit 109 results in a size reduction in the x-direction, i.e., the direction perpendicular to the scanning direction, by a ratio of 4:1.

[0202] The projection optical unit 109 results in an 8:1 size reduction in the y-direction, i.e., the scanning direction.

[0203] Other imaging scales are also possible. Imaging scales with the same sign and absolute value in the x and y directions, for example, with an absolute value of 0.125 or 0.25, are also possible.

[0204] The number of intermediate image planes in the x and y directions within the beam path between the object field of view 104 and the image field of view 110 may be the same or different depending on the design of the projection optical unit 109. An example of a projection optical unit with a different number of such intermediate images in the x and y directions is known from U.S. Patent Application Publication No. 2018 / 0074303.

[0205] To form illumination channels for illuminating the object field of view 104, in each case, one of the pupil facets 122 is assigned to exactly one of the field of view facets 120. In particular, this can result in illumination according to Köhler's principle. Using the field of view facets 120, the distant field of view is decomposed into multiple object field of view 104. The field of view facets 120 generate multiple images at intermediate focal points on the pupil facets 122 assigned to each of them.

[0206] Each of the field of view facets 120 is imaged onto the reticle 106 in an overlapping manner to illuminate the object field of view 104, by its assigned pupil facet 122. The illumination of the object field of view 104 is, in particular, as uniform as possible. This illumination preferably has a uniformity error of less than 2%. Field of view uniformity can be achieved by overlapping different illumination channels.

[0207] The illumination of the entrance pupil of the projection optical unit 109 can be geometrically defined by the arrangement of the pupil facets. The intensity distribution within the entrance pupil of the projection optical unit 109 can be set by selecting illumination channels that guide the light, particularly a subset of the pupil facets. This intensity distribution is also called the illumination setting.

[0208] Similarly desirable pupil uniformity within the region of the illuminated portion of the illumination pupil of the illumination optical unit 103 can be achieved by redistributing the illumination channels.

[0209] Further aspects and details of the illumination of the object field of view 104, and in particular the illumination of the entrance pupil of the projection optical unit 109, are described below.

[0210] The projection optics unit 109 may have a concentric entrance pupil. The concentric entrance pupil may be accessible. The concentric entrance pupil may also be inaccessible.

[0211] The entrance pupil of the projection optical unit 109 cannot generally be accurately illuminated using the pupil facet mirror 121. When the projection optical unit 109, which telecentrically images the center of the pupil facet mirror 121 onto the wafer 112, is imaged, the aperture rays often do not intersect at a single point. However, it is possible to find a surface area where the spacing determined by the pair of aperture rays is minimized. This surface area represents the entrance pupil, or a surface area in real space that is conjugate to the entrance pupil. In particular, this surface area exhibits finite curvature.

[0212] The position of the entrance pupil of the projection optics unit 109 may differ between the tangential beam path and the sagittal beam path. In this case, the imaging element, particularly the optical component of the transmission optics unit, should be placed between the second facet mirror 121 and the reticle 106. With the help of this optical component, it is possible to consider the different orientations of the tangential and sagittal entrance pupils.

[0213] In the arrangement of the components of the illumination optical unit 103 shown in Figure 1, the pupil facet mirror 121 is positioned within an area conjugate to the entrance pupil of the projection optical unit 109. The first field of view facet mirror 119 is positioned at an angle with respect to the object surface 105. The first facet mirror 119 is positioned at an angle with respect to the arrangement plane defined by the deflection mirror 118.

[0214] The first facet mirror 119 is positioned so as to be inclined with respect to the arrangement plane defined by the second facet mirror 121.

[0215] Figure 2 shows an exemplary DUV projection lithography apparatus 200. The DUV projection lithography apparatus 200 comprises an illumination system 201, a device known as a reticle stage 202 for receiving and precisely positioning a reticle 203 on a wafer 204, the reticle by which the subsequent structure is determined, a wafer holder 205 for holding, moving and precisely positioning the wafer 204, and an imaging unit, specifically a projection optical unit 206, which has multiple optical elements, in particular lens elements 207, and the multiple optical elements, in particular lens elements 207 are held by mounts 208 within a lens housing 209 of the projection optical unit 206.

[0216] In place of or in addition to the illustrated lens element 207, various refractive optical elements, diffractive optical elements, and / or reflective optical elements can be provided, including, in particular, mirrors, prisms, and end plates.

[0217] The basic functional principle of the DUV projection exposure apparatus 200 provides that the structure introduced into the reticle 203 is imaged onto the wafer 204.

[0218] The illumination system 201 provides a projection beam 210 in the form of electromagnetic radiation necessary to image the reticle 203 onto the wafer 204. The source used for this radiation can be a laser, a plasma source, or the like. The radiation is shaped using optical elements within the illumination system 201 so that the projection beam 210 has desired characteristics in terms of diameter, polarization, wavefront shape, etc., when incident on the reticle 203.

[0219] An image of the reticle 203 is generated using the projection beam 210 and transferred from the projection optics unit 206 onto the wafer 204 in a appropriately reduced form. In this case, the reticle 203 and the wafer 204 can be moved synchronously so that a region of the reticle 203 is imaged substantially continuously onto a corresponding region of the wafer 204 during a so-called scanning operation.

[0220] The gap between the final lens element 207 and the wafer 204 can optionally be replaced with a liquid medium having a refractive index greater than 1.0. The liquid medium can be, for example, high-purity water. Such a configuration is also called immersion lithography and has increased photolithographic resolution.

[0221] The use of the present invention is not limited to use in projection exposure apparatuses 100, 200, and is not limited in particular to use in projection exposure apparatuses 100, 200 having the configuration described. The present invention is suitable for any desired lithography system or microlithography system, but is particularly suitable for projection exposure apparatuses having the configuration described. The present invention is also suitable for EUV projection exposure apparatuses having a smaller image-side numerical aperture than that described in the context of Figure 1 and without occluding mirrors M5 and / or M6. In particular, the present invention is also suitable for EUV projection exposure apparatuses having an image-side numerical aperture of 0.25 to 0.5, preferably 0.3 to 0.4, and especially preferably 0.33. The present invention and the following exemplary embodiments should not be understood as being limited to any particular design.

[0222] The following figures illustrate the present invention in a highly simplified form, merely as an example.

[0223] Figure 3 shows a schematic diagram of one possible embodiment of the apparatus 1 for inspecting component 2.

[0224] Apparatus 1 is responsible for verifying a component 2 having a periodic structure 3 with substructures 5 arranged on a grid 4. Apparatus 1 comprises at least one measurement radiation source 6 for generating measurement radiation 7, an optical system 8, and a camera device 9. Apparatus 1 also includes a phase mask device 10 for influencing the phase angle of the measurement radiation 7, the phase mask device 10 having a dual grid 11 opposite to the target shape of the grid 4.

[0225] Preferably, the measurement radiation source 6 is configured to form a Köhler-type illumination of component 2.

[0226] Furthermore, a beam splitter device 6b is preferably provided for input coupling the measurement radiation 7 into the optical system 8. For the component 2 to be inspected, which is reflective rather than transmissive to the measurement radiation 7, reflected light illumination of component 2 as shown in Figure 3 is advantageous.

[0227] In the exemplary embodiment shown in Figure 3, the optical system 8 preferably includes at least one Fourier device 12 for performing an optical Fourier transform on the measurement radiation 7.

[0228] In the exemplary embodiment shown in Figure 3, the placement device 13 is more preferably present and configured to accommodate the component 2 such that the periodic structure 3 is positioned within the object plane of the Fourier device 12.

[0229] In the exemplary embodiment shown in Figure 3, the phase mask device 10 is also preferably positioned within the pupil plane of the Fourier device 12, opposite to the object plane.

[0230] In the exemplary embodiment of the apparatus 1 shown in Figure 3, the Fourier device 12 preferably includes a lens 14.

[0231] Furthermore, the Fourier device 12 has a first numerical aperture for observing the entire periodic structure 3 perpendicular to the object plane along the optical axis of the measured radiation 7 and the depth spread of component 2.

[0232] Alternatively, the Fourier device 12 has a second numerical aperture for observing only the cross-sectional region of the periodic structure 3 parallel to the object plane.

[0233] In this case, the first numerical aperture is preferably smaller than the second numerical aperture.

[0234] To switch between different numerical apertures, the apparatus 1 in the exemplary embodiment shown in Figure 3 preferably provides the Fourier device 12 to include an aperture diaphragm 15 configured to set the numerical aperture of the Fourier device 12.

[0235] At a given time point, the Fourier device 12 has either a first or second numerical aperture. However, the aperture diaphragm 15 allows for easy switching between numerical apertures at various time points.

[0236] In the exemplary embodiment of the apparatus 1 shown in Figure 3, a holding device 16 is preferably provided and configured to displace the phase mask device 10 within the pupil plane, preferably in both spatial directions of the pupil plane. In Figure 3, this displaceability is embodied by double arrows.

[0237] The exemplary embodiment of the apparatus 1 shown in Figure 3 also includes an imaging device 17 for imaging the measurement radiation 7 onto a camera device 9. In the exemplary embodiment, the imaging device 17 is embodied as part of the optical system 8.

[0238] In the exemplary embodiment shown in Figure 3, the Fourier device 12 preferably includes a zoom optical unit 12b.

[0239] In the exemplary embodiment shown in Figure 3, the measurement radiation source 6 is preferably configured to generate measurement radiation 7 of various wavelengths. Alternatively, or in addition to that, the measurement radiation 7 may be provided to be infrared radiation.

[0240] Alternatively, the beam splitter device 6a can be placed between component 2 and zoom optical unit 12b.

[0241] Preferably, the dual grid 11 is designed as the inverse of the one-dimensional and / or two-dimensional target shapes of the grid 4.

[0242] Figure 4 shows a schematic diagram of one possible embodiment of the phase mask device 10.

[0243] In the exemplary embodiment shown in Figure 4, the phase mask device preferably comprises dual substructures 18 arranged on a dual grid 11.

[0244] In the exemplary embodiment shown in Figure 4, the grid 4 has grid vectors 4a and 4b. The dual grid 11 has dual grid vectors 11a and 11b.

[0245] Furthermore, in Figure 4, the effect of the Fourier transform is embodied by arrow 12a.

[0246] Up to scaling, the dual lattice 11 or G*, which is opposed to lattice 4 or G, is given by its reciprocal. Thus, the following equation holds: GG* = 2πE, where E is the identity matrix. For a one-dimensional topological lattice, G and G* are, in particular, opposed lattice constants. Alternatively, GG* can be an integer multiple of 2πE.

[0247] Furthermore, in the exemplary embodiment of the phase mask device 10 shown in Figure 4, the dual substructure 18 is preferably at least generally circular.

[0248] Furthermore, located away from the dual substructure 18, that is, within the complementary portion of the dual substructure 18, the phase mask device 10 in the exemplary embodiment shown in Figure 4 provides a half-wavelength phase offset of the measurement radiation 7 compared to the dual substructure 18.

[0249] In the exemplary embodiments shown in Figures 3 and 4, the phase mask device 10 is preferably formed by an etched structure of a half-wavelength coating (λ / 2) on a transparent substrate.

[0250] In one exemplary embodiment (not shown), the phase mask device 10 is preferably provided to be digitally operable and / or transmittive or transmissive and / or reflective, and / or designed as a microelectromechanical system and / or as a spatial light modulator (SLM), particularly as a liquid crystal on silicon SLM (LCOS-SLM) and / or as a spatial light phase modulator.

[0251] Figure 5 shows a block diagram-type diagram of one possible embodiment of a method for verifying component 2.

[0252] In a method for verifying a component 2 comprising a periodic structure 3 having substructures 5 arranged on a grid 4, a measurement radiation source 6 for generating measurement radiation 7 is used in the generation block 30. An optical system 8 and a camera device 9 are also used. In the displacement block 31, the displacement of each substructure 5 from a reference substructure is determined by interferometry.

[0253] In the exemplary embodiment shown in Figure 5, an averaging block 32 is preferably provided, and in the averaging block 32, the reference structure is determined by the periodic averaging of the periodic structure 3.

[0254] Within the range of the averaging block 32, periodic averaging is preferably performed by superimposing the diffraction pattern 19 of the periodic structure 3 (see Figure 2) with the phase mask device 10 within the range of the overlapping block 33.

[0255] Within the range of the overlapping block 33, the phase angle of the measurement radiation 7 in the preferably circular dual substructure 18 on the dual grid 11, which is opposite to the target shape of the grid 4, is offset by half a wavelength of the measurement radiation 7 compared to the complementary portion of the dual substructure 18 on the phase mask device 10, thereby the measurement radiation 7 is preferably affected by the phase mask device 10.

[0256] The optical system 8 and camera device 9 are used in the imaging block 34.

[0257] Within the imaging block 34, the intensity pattern of the measurement radiation 7 on the camera device 9 is preferably determined by superimposing the diffraction pattern 19 of the periodic structure 3 with the phase mask device 10, and then imaging the measurement radiation 7 onto the camera device 9 by the imaging device 17.

[0258] Within the range of the overlapping block 33, the diffraction pattern 19 of the periodic structure 3 and the phase mask device 10 are preferably superimposed within the pupil plane of the Fourier device 12.

[0259] Within the imaging block 34, multiple interferograms are preferably recorded with each interferogram superimposed, while within the superimposing block 33, the phase mask device 10 is displaced to a different location within the pupil plane.

[0260] Preferably, various wavelengths of the measurement radiation 7 are used as part of the generation block 30, and the dual grating 11 is scaled, preferably within the range of the scaling block 35, in accordance with the wavelengths of the measurement radiation 7 used.

[0261] Within the range of the scaling block 35, the scaling of the dual grating 11 is preferably brought about by changing the phase mask device 10.

[0262] Alternatively or in addition thereto, the scaling of the dual grating 11 within the range of the scaling block 35 is preferably brought about by changing the focal length of the Fourier device 12 by means of the zoom optical unit 12b.

[0263] In this process, the pupil size and / or the illumination area of the phase mask device 10 preferably change.

[0264] Within the range of the offset block 31, component 2 is preferably additionally verified using a method for measuring the optical critical dimension, in which the intensity split of component 2 is simulated with the aid of a parameterization model of component 2.

[0265] Within the range of the superposition block 33, the dual grating 11 is preferably designed as the inverse of the one-dimensional and / or two-dimensional target shape of grating 4.

[0266] Furthermore, in the case of an exemplary embodiment of the method shown in FIG. 5, a NAND memory chip 20 (see FIG. 6) having periodically arranged through holes or vias 21 is preferably verified as component 2.

[0267] FIG. 6 shows a schematic view of a possible embodiment of the verified NAND memory chip 20.

[0268] In FIG. 6, component 2 verified by the above-described method and the above-described apparatus 1 is currently shown by the verified NAND memory chip 20. The periodic structure 3 is shown by the vias 21.

[0269] In the example shown in Figure 6, vias 21 are arranged on the grid 4 and have a cross-section representing a substructure 5. In this example, the cross-section representing the substructure 5 has a circular shape.

[0270] The NAND memory chip 20 shown in Figure 6 is realized in a 3D structure by deeply etching and / or coating periodically arranged vias 21, i.e., by multiple bilayer stacks 22.

[0271] Using an appropriate setting of the NA of the Fourier device 12, vias 21 can be observed along their depth spread, either in an averaged form in the case of a small NA of the lens 14, or in cross-section in the case of a large NA.

[0272] Figures 1 and 2 show projection exposure apparatuses 100 and 200 for semiconductor lithography, each comprising illumination systems 101 and 201 with a radiation source 102, and optical units 103, 109, and 206 with at least one optical element 116, 118, 119, 120, 121, 122, Mi, and 207, respectively. Apparatus 1 for examining component 2, particularly semiconductor components, is located within the projection exposure apparatuses 100 and 200 shown in Figures 1 and 2. Alternatively, or in addition thereto, the projection exposure apparatuses 100 and 200 shown in Figures 1 and 2 are configured to perform the method described in the context of Figure 5 for examining component 2, particularly semiconductor components.

[0273] The present invention is particularly suitable for projection lithography apparatuses 100, 200 shown in Figures 1 and 2, provided that they are configured to produce and verify semiconductor components embodied as NAND memory chips 20 having periodically arranged vias 21.

[0274] In the exemplary embodiments shown in Figures 1 and 2, the apparatus 1 for inspecting semiconductor components is preferably spatially separated from the exposure location of the semiconductor components. Furthermore, in each case, the method for inspecting the semiconductor components produced by the projection exposure apparatuses 100, 200 is preferably carried out spatially separated from the exposure location of the semiconductor components.

[0275] In one possible embodiment, the optical units of projection exposure apparatuses 100 and 200 can be incorporated into apparatus 1. [Explanation of Symbols]

[0276] 1 device 2 components 3 Periodic structure 4 lattice 4a, b lattice vectors 5 substructure 6 Measuring radiation source 6a Beam Splitter Device 7. Measured radiation 8 Optical system 9 Camera devices 10 Phase Mask Devices 11 Dual lattice 11a, b Dual lattice vectors 12 Fourier devices 12a Arrow 12b Zoom Optical Unit 13 Deployment Devices 14 lenses 15 Aperture diaphragm 16 Retaining devices 17 Imaging devices 18 Dual Substructures 19 Diffraction pattern 20 NAND memory chips 21 Beer 22 Bylayer Stacks 30 generated blocks 31. Shift Block 32 Averaging Blocks 33 Overlapping Blocks 34 Imaging block 35 Scaling block 100 EUV projection exposure apparatus 101 Illumination system 102 Radiation source 103 Illumination optical unit 104 Object field of view 105 Object plane 106 Reticle 107 Reticle holder 108 Reticle displacement drive 109 Projection optical unit 110 Image field of view 111 Image plane 112 Wafer 113 Wafer holder 114 Wafer displacement drive 115 EUV / Usage / Illumination radiation 116 Collector 117 Intermediate focal plane 118 Deflection mirror 119 First facet mirror / Field facet mirror 120 First facet / Field facet 121 Second facet mirror / Pupil facet mirror 122 Second facet / Pupil facet 200 DUV projection exposure apparatus 201 Illumination system 202 Reticle stage 203 Reticle 204 Wafer 205 Wafer holder 206 Projection optical unit 207 Lens element 208 Mount 209 Lens housing 210 Projection beam Mi mirror

Claims

1. An apparatus (1) for confirming a component (2) having a periodic structure (3) having substructures (5) arranged on a grid (4), the apparatus (1) comprising at least a measuring radiation source (6) for generating measuring radiation (7), an optical system (8), and a camera device (9), A phase mask device (10) for influencing the phase angle of the measurement radiation (7) is provided, the phase mask device (10) having a dual grid (11) opposite to the target shape of the grid (4). Apparatus (1) characterized by the following.

2. The phase mask device (10) has a dual substructure (18) arranged on the dual grid (11). The apparatus (10) according to claim 1, characterized in that

3. The dual substructure (18) is at least roughly circular. The apparatus (1) according to claim 2, characterized in that

4. The phase mask device (10) brings forth a phase offset of the measurement radiation (7) by half a wavelength relative to the complementary portion of the dual substructure (18) on the phase mask device (10), at a distance from the dual substructure (18). The apparatus (1) according to claim 2 or 3, characterized in that

5. The optical system (8) includes at least one Fourier device (12) for performing an optical Fourier transform on the measurement radiation (7). The apparatus (1) according to any one of claims 1 to 4, characterized in that

6. A placement device (13) is provided and configured to accommodate the component (2) such that the periodic structure (3) is positioned within the object plane of the Fourier device (12). The apparatus (1) according to claim 5, characterized in that

7. The phase mask device (10) is positioned within the pupil plane of the Fourier device (12) that is opposite to the object plane. The apparatus (1) according to claim 6, characterized in that

8. The Fourier device (12) includes a lens (14), - Having a first numerical aperture for confirming the entire periodic structure (3) perpendicular to the object plane, or - Does it have a second numerical aperture for confirming only the cross-sectional region of the periodic structure (3) parallel to the object plane? The apparatus (1) according to claim 6 or 7, characterized in that it is either one of the above.

9. The Fourier device (12) includes an aperture diaphragm (15) configured to set the numerical aperture of the Fourier device (12). The apparatus (1) according to claim 8, characterized in that

10. A holding device (16) is provided and configured to displace the phase mask device (10) within the pupil plane, preferably in both spatial directions of the pupil plane. The apparatus (1) according to any one of claims 7 to 9, characterized in that

11. The phase mask device (10) is formed by an etched structure of a half-wavelength coating on a transparent substrate. The apparatus (1) according to any one of claims 1 to 10, characterized in that

12. The phase mask device (10) is designed to be digitally operable and / or transmissive and / or reflective, and / or as a microelectromechanical system and / or as a spatial light modulator (SLM), particularly as a liquid crystal on silicon SLM (LCOS-SLM) and / or as a spatial light phase modulator. The apparatus (1) according to any one of claims 1 to 11, characterized in that

13. An imaging device (17) is provided for forming an image of the measurement radiation (7) onto the camera device (9). The apparatus (1) according to any one of claims 1 to 12, characterized in that

14. The Fourier device (12) includes a zoom optical unit (12b). The apparatus (1) according to any one of claims 5 to 13, characterized in that

15. - The measurement radiation source (6) is configured to generate measurement radiation (7) of various wavelengths, and / or - The measured radiation (7) is infrared radiation. The apparatus (1) according to any one of claims 1 to 14, characterized in that

16. The dual grid (11) is designed as the inverse of the one-dimensional and / or two-dimensional target shapes of the grid (4). The apparatus (10) according to any one of claims 1 to 15, characterized in that

17. A method for identifying a component (2) having a periodic structure (3) having substructures (5) arranged on a grid (4), wherein the method uses at least one measuring radiation source (6) for generating measuring radiation (7), an optical system (8), and a camera device (9), The displacement of each substructure (5) from the reference substructure is determined by interferometry. A method characterized by the following features.

18. The aforementioned reference substructure is determined by the periodic averaging of the periodic structure (3). The method according to claim 17, characterized in that

19. The periodic averaging is performed by superimposing the diffraction pattern (19) of the periodic structure (3) with the phase mask device (10). The method according to claim 18, characterized in that

20. The phase angle of the measurement radiation (7) within a preferably circular dual substructure (18) on a dual grid (11) opposite to the target shape of the grid (4) is offset by half a wavelength of the measurement radiation (7) compared to the complementary portion of the dual substructure (18) on the phase mask device (10), thereby the measurement radiation (7) is affected by the phase mask device (10). The method according to claim 19, characterized in that

21. The diffraction pattern (19) of the periodic structure (3) and the phase mask device (10) are superimposed within the pupil plane of the Fourier device (12). The method according to any one of claims 18 to 20, characterized in that

22. The focal length of the Fourier device (12) is changed by the zoom optical unit (12b). The method according to claim 21, characterized in that

23. Multiple interferograms are recorded with the phase mask device (10) displaced to a different location within the pupil plane for each interferogram. The method according to any one of claims 19 to 22, characterized in that

24. Various wavelengths of the measurement radiation (7) are used, preferably the dual grating (11) is scaled according to the wavelength of the measurement radiation (7) used. The method according to any one of claims 20 to 23, characterized in that...

25. The scaling of the dual grid (11) is - This is brought about by the change of the phase mask device (10), and / or - The Fourier device (12), which preferably includes a zoom optical unit (12b), changes the pupil size and / or the illumination area of ​​the phase mask device (10), resulting in: The method according to claim 24, characterized in that

26. The component (2) is further verified using a method for measuring optical limit dimensions, the intensity distribution of which is simulated with the help of a parameterized model of the component (2). The method according to any one of claims 17 to 25, characterized in that

27. A NAND memory chip (20) having periodically arranged vias (21) is identified as component (2). The method according to any one of claims 17 to 26, characterized in that

28. The dual grid (11) is designed as the inverse of the one-dimensional and / or two-dimensional target shapes of the grid (4). The method according to any one of claims 17 to 27, characterized in that

29. A lithography system, particularly a projection exposure apparatus (100, 200) for producing semiconductor components, comprising an illumination system (101, 201) equipped with a radiation source (102) and an optical unit (103, 109, 206) equipped with at least one optical element (116, 118, 119, 120, 121, 122, Mi, 207), wherein - An apparatus (1) for verifying a component (2) according to any one of claims 1 to 16, in particular an apparatus (1) for verifying the semiconductor component, and / or - The lithography system is configured to carry out a method for verifying a component (2) according to any one of claims 17 to 28, in particular a method for verifying a semiconductor component. A lithography system, particularly a projection exposure apparatus (100, 200) for producing semiconductor components, characterized by the above.

30. A lithography system according to claim 29, configured to produce and verify a semiconductor component designed as a NAND memory chip (20) having periodically arranged vias (21).

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