Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/21—Polarisation-affecting properties
  • G01N21/211—Ellipsometry
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B11/00—Measuring arrangements characterised by the use of optical techniques
  • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B11/00—Measuring arrangements characterised by the use of optical techniques
  • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
  • G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
  • G01B11/0616—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating
  • G01B11/0641—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating with measurement of polarization
  • G01B11/065—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating with measurement of polarization using one or more discrete wavelengths
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N21/88—Investigating the presence of flaws or contamination
  • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
  • G01N21/9501—Semiconductor wafers
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/70—Microphotolithographic exposure; Apparatus therefor
  • G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
  • G03F7/70605—Workpiece metrology
  • G03F7/70616—Monitoring the printed patterns
  • G03F7/70625—Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F30/00—Computer-aided design [CAD]
  • G06F30/20—Design optimisation, verification or simulation
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B2210/00—Aspects not specifically covered by any group under G01B, e.g. of wheel alignment, caliper-like sensors
  • G01B2210/56—Measuring geometric parameters of semiconductor structures, e.g. profile, critical dimensions or trench depth
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/21—Polarisation-affecting properties
  • G01N21/211—Ellipsometry
  • G01N2021/213—Spectrometric ellipsometry
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2201/00—Features of devices classified in G01N21/00
  • G01N2201/06—Illumination; Optics
  • G01N2201/061—Sources
  • G01N2201/06113—Coherent sources; lasers

Definitions

• the invention relates to a device and a method for measuring a substrate.
• CD critical dimensions
• Classic ellipsometry is used in the state of the art to measure layer thicknesses and optical material properties such as refractive index and degree of reflection. The measurement of coatings must take place without destroying the layers in order to prevent the substrate or the wafer from being damaged.
• spectroscopic ellipsometry and reflectometry have established themselves as metrological systems for process control and process optimization in the semiconductor industry. As a rule, relative changes or deviations are detected. Programs that are required for the simulation and evaluation of the measurement of simple systems are known in the prior art.
• US Pat. No. 6,912,056B2 specifies an apparatus and a method for measuring a multilayer on a substrate.
• the apparatus includes a measuring unit for measuring reflected light, the reflected light having been reflected from the substrate on which the multilayer is formed.
• a plurality of recipe data are inputted, each of the plurality of recipe data corresponding to a plurality of hypothetical multilayers, one of the hypothetical multilayers being initially assumed to be the multilayer actually formed on the substrate.
• a control unit calculates a plurality of theoretical spectra each of which indicates at least a thickness of each component layer of the hypothetical multilayer assumed to be the multilayer actually formed on the substrate using one set of the plurality of recipe data, the measured spectrum is compared with the plurality of theoretical spectra, whereby a temporary thickness of the multilayer is determined.
• the calculated temporary thickness must be within a permissible range, otherwise the selection of the temporary thickness will be repeated after changing the recipe data.
• the physical information includes a refractive index and an extinction coefficient of each component layer.
• US Pat. No. 7,196,793B2 also uses the data measured with spectroscopic ellipsometry, such as the change in polarization of the radiation ( ⁇ ( ⁇ i ) and ⁇ ( ⁇ i )) and compares this with simulated spectra to characterize thin two-layer systems on a substrate.
• the simulated spectra are adapted in the model until the slightest differences between simulated values ( ⁇ M ( ⁇ i ) and ⁇ M ( ⁇ i )) and measured values ( ⁇ E ( ⁇ i ) and ⁇ E ( ⁇ i )), the layer thickness (n) d (best) and the angle of incidence ⁇ (best) being varied.
• polarimetric scatterometry is used for the measurement of critical dimensions of periodic structures on wafers or semiconductor components.
• variable angle-based scatterometry is used to characterize structures that have been produced with nanoimprint lithography. These structures are a wire grid polarizer (WGP) and a photoresist grid. RCWA algorithms were used to produce the model.
• WGP wire grid polarizer
• RCWA algorithms were used to produce the model.
• Reflection ellipsometry has established itself primarily in the measurement of thin layers in the semiconductor industry and is therefore briefly explained.
• monolayers are mostly characterized.
• the reflection of linearly polarized, parallel and monochromatic light on the three-phase system substrate / layer / air is measured.
• reflection and refraction take place at two interfaces.
• reflection and refraction at each individual phase boundary must be taken into account.
• the material-characteristic complex refractive index ⁇ of the layer system or the layer thickness can be calculated.
• Transmission ellipsometry is used to measure optical properties. Since ellipsometry works non-destructively, this method is particularly suitable for process control.
• VASE variable angle-based spectral ellipsometry
• the object to be achieved by this invention is to overcome the problems of the prior art and, in particular, to provide an improved method and an improved device for measuring a multilayer substrate.
• the invention relates to a method for measuring a multilayer substrate, in particular with at least one structure with critical dimensions, in particular with a surface structure with critical dimensions, the method having at least the following steps, in particular the following sequence:
• the simulation created can advantageously be used to optimize the desired layer thicknesses, structures and materials.
• the invention further relates to a device for measuring a multilayer substrate, in particular with at least one structure with critical dimensions, in particular with a surface structure with critical dimensions, having:
• Thin, transparent or semitransparent layers or two-layer systems or multiple-layer systems can advantageously be measured, with also structured surfaces can be measured.
• Complex substrates can be measured with high accuracy.
• the information content increases by adding several measurement variables and / or several measurement methods.
• Such a combined measurement method is preferably used with RCWA as the calculation method and enables the characterization of complex samples that contain several layers and structures by obtaining information about diffraction and phase as well as topographical information.
• the newly used methods deliver results with realistic computing power and in an acceptable short computing time in process monitoring.
• the measurement technique is preferably at least one, preferably exactly one, of the following techniques:
• VUV-UV-Vis-NIR variable angle-based spectral ellipsometry (VASE) in reflection or transmission mode.
• the measuring range extends from vacuum ultraviolet (VUV) to near infrared (NIR), from 146 nm to 1700 nm.
• VASE variable angle-based spectral ellipsometry
• IR or medium IR (MIR) range in addition to reflection or transmission measurements, measurements with attenuated total reflection in ATR mode (attenauted total reflection) are possible (ATR spectroscopy).
• ATR spectroscopy The configuration with a spectroscopic ellipsometer is the preferred configuration and is used in a first embodiment according to the invention as the first measurement technique.
• An angle of incidence and / or a wavelength and / or a polarization state is / are preferably varied and measured.
• the RCWA (Rigorous Coupled-Wave Analysis) is preferably used to create the simulation.
• only one measurement technique is preferably used, with the independent measurement variables, angle of incidence and wavelength and the state of polarization being varied and measured.
• the angle is not varied.
• a second measurement technique is used in addition to the variable angle-based spectral ellipsometry and, if necessary, a third etc.
• Which and how many measurement methods are combined depends on the substrates to be examined and must can be selected case-specifically in the course of the model production.
• a combination of wavelength-resolved and angle-resolved measurement methods such as scatterometry or ellipsometry lead to a higher accuracy of the simulations.
• the means for measuring preferably comprises at least one optical device, in particular an ellipsometer and / or reflectometer and / or scatterometer and / or spectrometer.
• the device preferably has at least one data processing unit and at least one data processing system for processing and storing the data obtained by the means for measuring the substrate.
• the means for measuring preferably have at least one radiation source, in particular laser or broadband radiation source, at least one monochromator, at least one polarizer, at least one compensator, at least one substrate holder, at least one analyzer, and at least one detector, with the at least one polarizer performing the adjustment selected elliptical polarization states, in particular linear or circular, allows.
• All means for measuring the substrate are preferably arranged in the device.
• the invention describes a method for characterizing multiple layer systems with a (surface) structuring with several steps:
• a sufficiently large number of measurements is carried out for a selected, known system (also called substrate in the following), ie a sample produced.
• the samples can be multilayer systems with or without structures or surface structuring.
• wavelength-resolved and / or angle-resolved measurements are carried out, the polarization state being measured and varied.
• the selected sample (s) is measured, depending on the complexity, with at least one measurement technique, with all components for performing the different measurement techniques preferably being present in the device according to the invention. If necessary, individual device components can be exchanged, added or removed. By adding several measurement methods, the information content of the recorded reference signatures increases.
• the sample to be measured is transferred to a further measuring device so that further measurements can be carried out using different measuring techniques.
• suitable measurement techniques for obtaining information are in particular scatterometry, ellipsometry, reflectometry, spectroscopy and / or diffractometry.
• the measurements can be carried out, for example, with a variable polarization of the measuring beam, with a change in the angle of incidence and with a change in the wavelength.
• a combination of wavelength-resolved and angle-resolved measurement methods lead to a higher accuracy of the simulations.
• measurements can be carried out not only in reflection mode but also in transmission mode in order to obtain additional information and data.
• the measurement techniques are also selected on the basis of the optical properties of the individual layers of a layer system.
• one layer can be largely transparent while one or more additional layers absorb or reflect more strongly.
• a suitable model is created on the basis of the recorded data, preferably with RCWA (Rigorous Coupled-Wave Analysis) as the calculation method.
• RCWA Ragorous Coupled-Wave Analysis
• Newly developed complex simulation algorithms are used to create models. The simulations enable various effects in metrology to be taken into account by comparing the measurement result and the simulation result for known samples. For this, model-based measurements are carried out. If the measured sample consists of several layers and (surface) Structures, increases the complexity of the system and the number of parameters to be determined.
• the recurring steps of measurement, model production or model optimization and simulation are necessary. If the measurement results and the simulation results do not match within a permissible range, the model must be further optimized. If the measurement results and the simulation results agree within a permissible range, the simulation can be used to analyze further samples.
• the configuration with a spectroscopic ellipsometer for example VASE, is the preferred configuration according to the invention and is used in a first embodiment according to the invention as the first measuring technique.
• Which and how many measurement methods are used must be determined individually for each system to be characterized.
• the measurement methods must provide experimental measurement data that are sensitive to many of the parameters of interest without the parameters being too correlated. Examples of parameters are, for example, the height and the width for surface structures and the layer thickness for an n-th layer.
• RCWA is used to calculate the lattice diffraction, whereby the sample is divided into several individual layers.
• the RCWA algorithms enable the critical dimensions of the structures under investigation to be determined. These are, for example, the height or depth of the structures, the width and the length of the structures, angles (e.g. side wall angles), remaining layer thickness (s) and surface roughness.
• the measurements can be carried out for positive and / or negative periodic structures.
• correlation analyzes and sensitivity analyzes are carried out in order to assess the quality of the reconstruction on the basis of the measurements carried out.
• the optimized model is used to characterize unknown samples, whereby the sample must be assigned to known sample systems. Layers and structural dimensions are reconstructed by comparing the measured and simulated spectra. The simulated spectra are used as a data set to reconstruct the parameters sought.
• - morphology critical dimensions of the examined structures are, for example, the height or depth of the structures, the width and the length of the structures, angles (e.g. side wall angles), remaining layer thickness (s) and surface roughness.
• the developed, optimized model is used not only for the calculation of desired parameters of further analog substrates and analog (layer) materials, but also for the optimization of desired layer thicknesses, structures and Materials.
• a layer thickness or a structure dimension can be optimized using the model according to the invention on the basis of the desired parameter size.
• Samples are substrates that have been processed or treated with the methods known in the semiconductor industry, in particular coated and / or embossed and / or bonded and / or etched and / or treated with plasma, and / or treated with light, for example laser, etc.
• Master stamps, working stamps and microfluidic assemblies are also understood as samples.
• a substrate or semiconductor substrate is understood to mean a not yet separated, in particular round, semifinished product from the semiconductor industry.
• a substrate is also understood to mean a wafer. While the substrate can be any diameter, the substrate diameter is more specifically 1 ", 2", 3 “, 4", 5 “, 6", 8 “, 12", 18 “, or greater than 18".
• a substrate can also have a rectangular shape or at least a shape deviating from the circular shape.
• the samples to be characterized contain in particular one or more of the following components and / or coatings:
• First layers such as primer layers
• the method according to the invention is not limited to the samples mentioned above and is generally suitable for multilayer systems with or without structuring with critical dimensions, as long as the sample can be measured with at least one of the measurement techniques according to the invention (ellipsometry, scatterometry, spectroscopy, diffractometry and reflectometry).
• the analysis methods can, in addition to determining layer thicknesses and structures with critical dimensions, be used for the following applications:
• Characterization of the chemical composition of materials for example paints, work stamp materials, master stamp materials, first layers, non-stick materials, etc.
• - Characterization of the radiation stability of materials such as paints, work stamp materials, master stamp materials, first layers, non-stick materials, etc.
• Electron beam lithography and / or chemical etching processes have been produced
• the method according to the invention can be used for quality control of the samples produced with multilayer systems and / or structuring.
• the quality of work stamps for nanoimprint lithography is characterized. These work stamps can consist of several layers with different thicknesses and materials. One of the layers is structured (e.g. soft stamp material layer). Several parameters can be relevant for the quality.
• the quality control can be carried out immediately after production and / or after certain time intervals to check the wear and tear or aging, e.g. in use.
• the method according to the invention can be used to optimize a manufacturing process for monitoring the manufactured products up to the desired ones Properties ie parameters can be achieved reproducibly.
• the spatial homogeneity of selected parameters can, for example, also be determined using the method according to the invention and used as a selection criterion.
• the applications according to the invention are not restricted to the abovementioned multilayer systems (with or without structuring).
• the device comprises optical devices such as an ellipsometer and / or reflectometer and / or scatterometer and / or spectrometer, and a data processing unit or a data processing system for processing and storing the data obtained by the optical devices.
• optical devices such as an ellipsometer and / or reflectometer and / or scatterometer and / or spectrometer
• data processing unit or a data processing system for processing and storing the data obtained by the optical devices.
• the essential components of the optical devices are: at least one radiation source (e.g. laser or broadband radiation source), at least one monochromator, at least one polarizer, at least one compensator, a sample holder, at least one analyzer, and at least one detector.
• the polarization optics enable selected elliptical polarization states (linear, circular, etc.) to be set.
• the measurements are not restricted to reflection and can also be carried out in transmission or in ATR mode.
• a corresponding ATR holder for substrate and / or ATR crystal and ATR optics are added as additional or alternative components.
• wavelength-resolved and angle-resolved measurements are carried out, it being possible to vary the polarization state. If the systems to be examined are less complex, the angle is not varied since the wavelength and polarization state are sufficient information.
• the configuration with a spectroscopic ellipsometer, wherein the variable angle-supported spectral ellipsometry is preferably selected is the preferred configuration according to the invention and is used in a first embodiment according to the invention as the first measuring technique.
• the selected samples can be measured using several measurement techniques, with all components for performing the different measurement techniques preferably being present in the device according to the invention. If necessary, individual device components can be exchanged, added or removed. By adding several measurement methods, the information content of the recorded reference signatures increases according to the invention.
• the sample to be measured is transferred to a further measuring device so that further measurements can be carried out using different measuring techniques.
• Typical components of ellipsometers are, for example, a light source, a polarizer, possibly a compensator (for example a 1/4 plate), a sample holder, an analyzer, if required a monochromator, and a detector.
• 2c cross-sectional view of a third substrate with a multilayer system and a surface structuring with positive periodic trapezoidal structures
• 2d Top view of four exemplary embodiments of periodic structures (7 rectangular, 7 '"linear, 7 IV circular and 7 V a non-regular shape),
• Figure la shows a flow diagram of the method according to the invention.
• a comparison is made between the measurement result and the simulation result.
• the recurring method steps of measurement 120, model production 130 or model optimization 140 and renewed simulation are necessary.
• a substrate also referred to below as a sample
• a substrate with a plurality of thin layers and a (surface) structuring
• the system to be examined is therefore known and is used for model production and optimization. If necessary, several precisely known reference substrates are produced and the measurement results are used to validate and optimize the simulation model developed.
• the substrate is irradiated with electromagnetic radiation at a defined angle of incidence and the reflected radiation is measured, for example, as a function of the wave number and / or the angle.
• the measurements are not restricted to reflection and can also be carried out in transmission be performed.
• Several measurement techniques can be used to increase the reliability and / or the accuracy of the calculation process.
• the suitable measurement techniques for obtaining information are in particular scatterometry, ellipsometry, reflectometry, spectroscopy and / or diffractometry.
• either the entire multilayer system is measured after production or each individual layer is produced step by step and measured one after the other.
• the individual layers of the multilayer system have a layer thickness of more than 20 nm (greater than or equal to 20 nm) and the refractive index of the individual layers is known.
• the entire multilayer system is measured after production has been completed. For example an imprint stamp for imprint or nanoimprint lithography with a structured imprint layer.
• the sample contains very thin layers with a layer thickness below 20 nm with a known refractive index.
• very thin layers in particular layers with a layer thickness in the lower nm range to sub-nm range, each individual layer is produced and measured before the next layer is produced on top.
• the sample is measured after each layer application, for example an ASL layer. All measured data of the sample, which has been measured layer by layer, are taken into account for the production of the model. If necessary, layers with a layer thickness of more than 20 nm can also be measured individually during the production process of the sample, depending on the refractive index and the available material information.
• a sample contains an intermediate layer with a layer thickness of more than 20 nm but with an unknown refractive index.
• measurements are carried out after the application of individual layers with a layer thickness of more than 20 nm, and for the entire multilayer system after production has been completed.
• RCWA Radigorous Coupled Wave Analysis
• RCWA is preferably used as the calculation method for calculating the interaction of light with multilayer systems and nanostructures and microstructures. RCWA is used to calculate the lattice diffraction, whereby the sample is divided into several individual layers. This model concept was further developed and supplemented according to the invention.
• the further development according to the invention advantageously enables, with the simulation model from method step 130, the simultaneous evaluation of the diffraction of incident (plane) waves on the multilayer system and on the structures.
• Multi-layer systems and non-planar layers i.e. Structures determined with very high reliability and accuracy through the use of polarized light with ellipsometry.
• a simulation of a multilayer system with (surface) structuring can be calculated.
• the deviation between the experimental data and the simulated data should be as small as possible (140).
• a complex system according to the invention as shown for example in FIG. 2a with several layers and a surface structuring, this can be done in FIG
• the model developed according to the invention correctly describes the sample physically. This enables simulation with high reliability.
• a comparison between the measurement result and the simulation result is carried out in a fourth method step 140.
• the recurring steps of measurement, model production or model optimization (model fitting) and renewed simulation are necessary.
• the aim of the adjustment is that the model i.e. Adapt the generated data sets to the measured data sets (i.e. experimental data) as best as possible. If this is not (yet) the case, the model is further optimized in method step 130. If this is the case, the developed model can be used in method step 150 to determine the desired parameters.
• a mathematical analysis of the developed model systems can also be used if necessary, especially for the development of generic model systems.
• FIG. 1b shows a flow diagram of the method according to the invention when a finished simulation model according to the invention is used for a multilayer system with (surface) structuring.
• a developed model is available for routine simulations.
• the system parameters are fixed.
• a known sample - ie the number of planar and / or non-planar (ie structured) layers and the layer materials are known - is measured according to the invention in method step 120 and, after comparing experimental and generated data sets (140), the desired parameters are determined ( 150).
• FIG. 2a shows a cross-sectional view of a substrate 2 according to the invention with a plurality of thin coatings 3-6 and a surface structure 7.
• the number and the thickness of the coatings are not restricted to the embodiments from FIGS. 2a to 2c.
• the thickness of the coatings is not drawn to scale for the sake of clarity.
• Figures 2a to 2c show similar embodiments with different surface structures 7, 7 ', 7 ′′.
• the last coating 6, 6 ', 6 ′′ can consist, for example, of a photoresist or an embossing compound, which by means of Lithography or nanoimprint lithography has been structured.
• the structures 7, 7 ', 7 "have dimensions in the nanometer range.
• the surface 6o, 6'o, 6 “o of the structured coating defines the remaining layer thickness.
• FIG. 2a shows a multilayer system 1 with a surface structuring with positive periodic structures 7.
• Figure 2b shows a further embodiment of a multilayer system 1 with a surface structure with negative periodic structures 7 ‘.
• FIG. 2c shows a third embodiment of a multilayer system 1 ′′ with a surface structuring with positive periodic trapezoidal structures 7 ′′.
• the incident light hits these (mostly) periodic, area-covering structures that can represent an optical diffraction grating.
• the critical dimensions of the examined structures 7, 7 ‘, 7“ include the height or depth of the structures, the width and the length of the structures, the angles, for example the side wall angles, the remaining layer thickness (s) and the surface roughness.
• FIG. 2d shows, in a top view of several cutouts, a comparison of further possible surface structures 7, 7 ′ ′′, 7 IV and 7 V of a sample according to the invention.
• models are developed which enable a reliable characterization of complex multilayer systems with a (surface) structuring according to the structures from FIGS. 2a to 2d.
• the structures 7 are quadrilaterals, in particular squares.
• the structures 7 '" are periodic area-wide linear structures.
• the structures 7 IV are circular. Structures with more complex or irregular structural shapes, such as, for example, the structures 7V from FIG. 2d, do not pose a problem for the method according to the invention and are recorded and correctly reproduced in the production of the model.
• the non-planar layer with a structure is the top layer 6, 6 ', 6 "of a multilayer system 1, 1', 1".
• the non-planar layer with a structure is located between two layers in the multilayer system.
• a structured stamping compound is coated with an ASL coating after stamping for use as a work stamp.
• a multilayer system contains more than one non-planar layer with a structure.
• FIG. 3 shows the optical components of a first embodiment of a device 13 according to the invention.
• a polarizer (P) 9 converts the non-polarized light from a radiation source 8 into linearly polarized light.
• the radiation passes through an analyzer (A) 10.
• the electromagnetic radiation is elliptically polarized when it is reflected on the sample 1.
• the analyzer 10 again changes the polarization of the reflected electromagnetic radiation, which then strikes a detector (D) 11.
• a polychromatic radiation source is used, so that a selected wavelength range is used in the measurement method.
• monochromatic radiation is used, a laser preferably being used as the radiation source.
• Several radiation sources can be present in the device at the same time and / or can be exchanged if necessary.
• optical components are, for example, optical filters, compensators (e.g. a ⁇ / 2 plate), monochromators, and different optical variable attenuators that can be used if required depending on the measurement technology and / or wavelength range. These components are known to the person skilled in the art and are not described in more detail.
• the measurement techniques according to the invention differ in the arrangement and the type of optical components.
• the analyzer 10 can be designed to rotate, for example.
• variable angle-based spectral ellipsometry offers a wide range of wavelengths. This will increase the information content of the measured data and the accuracy of the simulations.
• a goniometer enables variable angle measurements.
• the combination of wavelength-resolved and angle-resolved measurements is the preferred embodiment and, according to the invention, leads to a higher reliability of the simulations. This combination is carried out according to the invention with VASE as the preferred measuring technique.
• measurements can be carried out not only in reflection mode but also in transmission mode in order to obtain additional information and data if required.
• the device 13 comprises optical devices and a data processing unit 12 for processing and storing the data obtained from the optical devices.
• a receiving device serves to receive and fix the sample or the substrate.
• the receiving device can be moved in a Z direction as required. Rotation and / or tilting of the receiving device is also possible.
• the receiving device can be heated and tempered in a temperature range between 0 ° C and 1000 ° C, preferably between 0 ° C and 500 ° C, even more preferably between 0 ° C and 400 ° C, most preferably between 0 ° C and 350 ° C .
• the receiving device can alternatively also be cooled with a cooling device.
• the receiving device can be cooled in a temperature range between -196 ° C and 0 ° C.
• the temperature of the receptacle can be adjusted with a temperature control arrangement.
• the recording device can also have sensors (not shown) with the aid of which physical and / or chemical properties can be measured.
• These sensors can be temperature sensors, for example.
• the receiving device contains a fluid cell which Measurements allowed under liquids.
• the liquid cell is a flow cell. This means that multi-layer systems with or without (surface) structuring can be measured in a liquid environment.
• the electrochemical response of a multilayer system can be characterized with the liquid cell in a special application.
• the fluid cell can also be designed as an electrochemical cell with a reference electrode, counter electrode and optical windows for the spectroscopic ellipsometric measurements.
• the device 13 according to the invention can advantageously also be operated in a vacuum or at ambient pressure under a gas atmosphere.
• the gas atmosphere is preferably an inert gas atmosphere, for example nitrogen (N 2 ).
• N 2 nitrogen
• the device 13 according to the invention can preferably be evacuated and heated.
• the device has means for introducing one or more gaseous components.
• a loading device preferably a lock, allows the samples to be loaded.
• the device can be constructed in such a way that measurements can be carried out in situ.
• a computer-aided data processing system 12 stores and processes the data obtained from the optical devices to simulate the multilayer systems according to the invention (with or, if necessary, without structuring) with the simulation algorithms further developed according to the invention.
• the simulation models according to the invention make it possible for the first time with the proposed method to detect and characterize several thin layers and a (surface) structuring simultaneously and with a high degree of reliability. LIST OF REFERENCE SYMBOLS 1, 1 ', 1 ′′ substrate / multilayer system with (surface) structuring

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• 2019
  • 2019-11-28 US US17/774,612 patent/US20220390356A1/en active Pending
  • 2019-11-28 WO PCT/EP2019/082881 patent/WO2021104631A1/de unknown
  • 2019-11-28 CN CN201980102109.7A patent/CN114616455A/zh active Pending
  • 2019-11-28 EP EP19813462.9A patent/EP4065957A1/de active Pending
  • 2019-11-28 JP JP2022526364A patent/JP2023509816A/ja active Pending
  • 2019-11-28 KR KR1020227015559A patent/KR20220103713A/ko active Search and Examination
• 2020
  • 2020-11-13 TW TW109139807A patent/TW202127005A/zh unknown

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