Abstract: A surface inspection apparatus includes units illuminating repetitive patterns formed on a surface of a suspected substance and measuring a variation in an intensity of regular reflection light caused by a change in shapes of the repetitive patterns, units illuminating the repetitive patterns with linearly polarized light, setting an angle formed between a repetitive direction of the repetitive patterns and a direction of a plane of vibration of the linearly polarized light at a tilt angle, and measuring a variation in a polarized state of the regular reflection light caused by the change in the shapes of the repetitive patterns, and a unit detecting a defect of the repetitive patterns based on the variation in the intensity and the variation in the polarized state of the regular reflection light.

Abstract: Simultaneous measurement of two orthogonally polarized beams upon diffraction from a substrate is done to determine properties of the substrate. Linearly polarized light sources with their radiation polarized in orthogonal directions are passed via two non-polarizing beamsplitters, one rotated by 90° with respect to the other. The combined beam is then diffracted off a substrate before being passed back through a non-polarizing beamsplitter and through a phase shifter and a Wollaston prism before being measured by a CCD camera. In this way, the phase and intensities for various phase steps of the two polarized beams may thereby be measured and the polarization state of the beams may be determined. If the phase shifter is turned to zero (i.e. with no phase shifting), the grating of the substrate has its parameters measured with TE and TM polarized light simultaneously with the same detector system.

Abstract: An illuminating optical system of an inspection device selects an arbitrary wavelength region from the light source, and epi-illuminates the sample via the polarizer and the objective lens. A detecting optical system includes an analyzer having a polarization plane intersected with a polarization direction of the polarizer. Then, the detecting optical system detects light from the sample via the objective lens and the analyzer, and acquires a Fourier image of a sample surface based on this light. An imaging section images the Fourier image. An analyzing section performs computation for processing for determining a notable area to be affected by a state of the pattern more than other areas in the Fourier image.

Abstract: Provided is an unevenness detecting apparatus comprising a determining section that determines a polarization state of returned light obtained from radiated light; an uneven portion judging section that judges whether an uneven portion is present based on the polarization state determined by the determining section; a convex/concave identifying section that identifies whether the uneven portion is convex or concave based on image data, captured by an image capturing element, of the uneven portion; and an output section that outputs information identifying whether the uneven portion is convex or concave.

Abstract: Light is irradiated onto a glass substrate of an organic EL element, and the characteristics of an organic film are analyzed. In the sample analyzing apparatus, in such a way that the glass substrate is located on the upper side, the organic EL element is placed on a stage. The light is irradiated towards the glass substrate, and an amplitude ratio and a phase difference which are related to the organic EL element are measured. Also, the sample analyzing apparatus selects a model of a structure corresponding to reflected lights K1 to K3 of the irradiated light and calculates the amplitude ratio and the phase difference. The sample analyzing apparatus compares the measured result and the result calculated from the model, and properly executes the fitting, and determines the best model among the several models and then analyzes the characteristics related to the organic EL element.

Abstract: Scattered light that originates from the surface roughness of silicon or other metallic films is distributed more strongly at positions closer to the starting position of the scattering. Of all scattered-light detection signals obtained during multi-directional detection, therefore, only a detection signal of forward scattered light can be used to detect micro-defects, and only a detection signal of backward scattered light can be used to detect the surface roughness very accurately.

Abstract: Maintenance of information content in a focused beam of electromagnetic radiation when the intensity thereof is attenuated by application of an aperture-like element.

Abstract: The present invention relates to an ellipsometer, and more particularly, to an ellipsometer to find out the optical properties of the sample by analyzing the variation of the polarization of a light which has specific polarisation then reflected on a surface of the sample.

Abstract: A device (2) for evaluating the state of wetting of a surface (8) includes an emitter (4) emitting a beam (F, F1, F2) which is incident in the direction of the surface (8) and a single element (12) for receiving the beam reflected by the surface (8). The device includes: A polarisation (10, 13, 14) including a first polarisation zone (13) and a second polarisation zone (14) designed to polarise a first part (F1) and a second part (F2) of the beam in a first and a second polarisation direction; and a evaluation element (28) for calculating a polarisation ratio between the polarisations of the first part of the reflected beam and the second part of the reflected beam to evaluate the state of wetting of the surface (8). Also described is an evaluation process and an associated indicator device.

Abstract: An oxygen sensor using the principle of surface plasmon resonance, capable of measuring an oxygen concentration in a measurement chamber by detecting a change in resonance angle or refractive index using field enhancement effects, is provided. An oxygen transmission rate measurement system including the oxygen sensor is also provided. In this invention, only a change in voltage is measured at a fixed angle, thus achieving rapid measurement, and also, a single wavelength light source is used, thus reducing the size of the oxygen sensor and oxygen transmission rate measurement system.

Abstract: A process step in fabricating a structure on a wafer in a wafer application having one or more process steps and one or more process parameters is controlled by determining a correlation between a set of profile models and one or more key profile shape variables. Each profile model is defined using a set of profile parameters to characterize the shape of the structure. Different sets of profile parameters define the profile models in the set. The one or more key profile shape variables include one or more profile parameters or one or more process parameters. One profile model is selected from the set of profile models based on the correlation and a value of at least one key profile shape variable of the process of the wafer application to be used in fabricating the structure. The structure is fabricated in a first fabrication process cluster using the process step and the value of the at least one key profile shape variable. A measured diffraction signal is obtained off the structure.

Abstract: An apparatus is disclosed for obtaining ellipsometric measurements from a sample. A probe beam is focused onto the sample to create a spread of angles of incidence. The beam is passed through a quarter waveplate retarder and a polarizer. The reflected beam is measured by a detector. In one preferred embodiment, the detector includes eight radially arranged segments, each segment generating an output which represents an integration of multiple angle of incidence. A processor manipulates the output from the various segments to derive ellipsometric information.

Abstract: A pattern inspection apparatus which compares images of regions, corresponding to each other, of patterns that are formed so as to be identical and judges that non-coincident portions in the images are defects. The pattern inspection apparatus is equipped with an image comparing section which plots individual pixels of an inspection subject image in a feature space and detects excessively deviated points in the feature space as defects. Defects can be detected correctly even when the same patterns in images have a brightness difference due to a difference in the thickness of a film formed on a wafer.

Abstract: A system for probing a DUT is disclosed, the system having a pulsed laser source, a CW laser source, beam optics designed to point a reference beam and a probing beam at the same location on the DUT, optical detectors for detecting the reflected reference and probing beams, and a collection electronics. The beam optics is a common-path polarization differential probing (PDP) optics. The common-path PDP optics divides the incident laser beam into two beams of orthogonal polarization—one beam simulating a reference beam while the other simulating a probing beam. Both reference and probing beams are pointed to the same location on the DUT. Due to the intrinsic asymmetry of a CMOS transistor, the interaction of the reference and probing beams with the DUT result in different phase modulation in each beam. This difference can be investigated to study the response of the DUT to the stimulus signal.

Abstract: A micro-distance measuring method includes: collecting measurement light projected from a light projection part by lens, inversely correcting astigmatism of the measurement light by a correction optical part, making the measurement light incident on a translucent substrate at an oblique angle so that the astigmatism of the measurement light inversely corrected by the correction optical part is canceled, projecting the measurement light, passing through the translucent substrate, on an object adjacent to the translucent substrate, and receiving light reflected on the object, detecting a phase difference between polarized components of the received light, which are different in the vibration direction, and determining a distance between the substrate and the object on the basis of the detected phased difference.

Abstract: A support designed for observing between intersecting polarizers an object located in its vicinity in a medium (3) of index n0 with incident convergent incoherent illumination under an angle ?0 at a wavelength ?. The support includes a substrate (1) with complex refractive index n2 and a layer (2) of refractive index n1 and thickness e1. The value of the thickness e1 of the layer (2) is at ±2% such that d2?/de21 lnIóI2=0 with Ó=Ó01+Ó12 (1+?01)e(?2j?1)+Ó01 ?12e (?4j?1)/1+r01(p)+r12(p)e(?2j?1))(1+r01(s)r12(s)e(?2j?1)). Observation devices incorporating such a support are also disclosed.

Abstract: An ellipsometer is used to analyze each of a plurality of sample portions that each include a substrate portion with a coating portion thereon, the substrate portions corresponding to respective spaced portions of a part with a curved surface. For each sample portion, the analysis includes: directing onto the coating portion a beam of radiation that includes first and second components with different polarizations; detecting energy of each of the first and second components reflected by the sample portion; and generating data that includes, for each of a plurality of different wavelengths, information regarding a change caused by the sample portion to a relationship between the first and second components.

Abstract: An improved procedure for calibrating the azimuth angle in a metrology module for use in a metrology system that is used for measuring a target on a wafer, and the metrology modules can include oblique Spectroscopic Ellipsometry (SE) and unpolarized or polarized spectroscopic reflectometer devices.

Abstract: A device includes an incident arm, a detection arm, a sample stage, and an image processing computer. The incident arm includes a light source and a first polarizing element, and is disposed on one side of the sample stage. The detection arm includes a second polarizing element and a photoelectric detector, and is disposed on a light-detection path. The photoelectric detector is connected to the computer. The device further includes a device for adjusting polarization angles of the first and second polarizing elements. A method includes: illuminating a sample surface using linearly polarized light with a certain polarization angle; detecting outgoing polarized light by a photoelectric detector; adjusting polarization angles of the incident and detected polarized light, and repeating the above two steps to obtain a series of polarized images, each image corresponding to incident and detected polarization angles; and computer processing the obtained images to obtain sample information.

Abstract: Apparatus and method for manufacturing a semiconductor device through a layer material dimension analysis increase productivity. The method includes performing a semiconductor manufacturing process of at least one reference substrate and at least one target substrate in a semiconductor process device, detecting a reference spectrum and a reference profile for the reference substrate, determining a relation function between the detected reference spectrum and reference profile, detecting a real-time spectrum of the target substrate, and determining in real time a real-time profile of the target substrate processed in the semiconductor process device by using the detected real-time spectrum as a variable in the determined relation function.

Abstract: An examining device adapted to examining a transmittance of a display panel is provided. The examining device includes a light source, a first polarizer, a photodetector, a second polarizer, at least one first reflector and at least one second reflector. The light source and the photodetector are respectively disposed on both sides of the display panel. The second polarizer is disposed between the display panel and the photodetector. The first reflector is disposed between the display panel and the second polarizer. The second reflector is disposed between the display panel and the first polarizer. Light emitting from the light source successively passes via the first polarizer, the display panel, the first reflector, the display panel, the second reflector, the display panel, the second polarizer and then emits into the photodetector.

Abstract: An image pickup including a lens array having a substrate on which multiple lenses are provided; a filter including at least two polarizer areas with respective perpendicular axes which are separated according to beams of light which have passed through the respective lenses of the lens array; an image pickup unit including multiple image pickup areas that shoots images of an object by receiving the beams of light which have passed through the respective corresponding polarizer areas of the filter; a signal processing unit that processes image signals of the images of the object shot in the multiple image pickup areas of the image pickup unit, wherein a vertical polarization image is shot at one of the image pickup areas and a horizontal polarization image is shot at another image pickup area, and wherein the signal processing unit produces an image according to the polarization ratio of the vertical polarization image to the horizontal polarization image shot in the image pickup unit.

Abstract: A system for reducing reflections of a beam of electromagnetic from the back of a sample, including methodology of use.

Abstract: Disclosed are scanning devices which measure and quantify optical properties within an object such as the absorption of light, refractive index, light scattering, fluorescence, and phosphorescence. Through the use of two rotating plane mirrors and two paraboloid mirrors, a laser light beam is made to traverse the object to be scanned wherein the beam is always parallel to the optical axis. The invention provides an improvement over previously reported scanning devices by virtue of increased speed and resolution. Two-dimensional projections gleaned by each scan of the object are reconstructed into a three-dimensional image through the use of various computer techniques.

Abstract: A rotating compensator spectroscopic ellipsometer or polarimeter system having a source of a polychromatic beam of electromagnetic radiation, a polarizer, a stage for supporting a material system, an analyzer, a dispersive optics and a detector system which comprises a multiplicity of detector elements, the system being functionally present in an environmental control chamber and therefore suitable for application in wide spectral range, (for example, 130-1700 nm). Preferred compensator design involves a substantially achromatic multiple element compensator systems wherein multiple total internal reflections enter retardance into an entered beam of electromagnetic radiation, and the elements thereof are oriented to minimize changes in the net retardance vs. the input beam angle resulting from changes in the position and/or rotation of the system of elements.

Abstract: A terahertz spectroscopic apparatus includes a polarization beam splitter transmitting or reflecting a linearly polarized terahertz wave, a quarter wave plate imparting a phase difference of 90° to a terahertz wave impinging thereon, and an optical member guiding a circularly polarized terahertz wave impinging thereon from the polarization beam splitter via the quarter wave plate to an irradiation surface.

Abstract: An optical apparatus for the inspection of nucleic acid probes includes: a holder (22) for housing a chip (1) for analysis of nucleic acids, containing nucleic acid probes (12, 12?); a light (24), for supplying an excitation radiation (WE) to the holder (22); and an optical sensor (25) for detecting images (IMG) of the nucleic acid probes (12, 12?), when a chip (1) is housed in the holder (22). The light source (24) is configured for polarizing the excitation radiation (WE) according to a excitation polarization direction (DE). Furthermore, the apparatus is provided with a sensing polarizing filter (27), which is arranged so as to intercept a reflected portion (WR) of the excitation radiation (WE), directed towards the optical sensor (25). The sensing polarizing filter (27) has a direction of the sensing polarization (DS) transverse to the excitation polarization direction (DE).

Abstract: A particle discriminator using circularly polarized light projected through a channel having target particles. Light may be propagated through the channel, with some light scattered separated into forward angle scattered light, small angle scattered light and unscattered light. The forward angle scattered light may be linearly polarized and detected. The small angle scattered light may be linearly polarized in a direction orthogonal to the direction of the polarization of the forward angle scattered light, and at least both these kinds of light may be detected. Data from these detected kinds of light may be analyzed to discriminate particles from one another.

Abstract: Method of determining defects in a substrate, the method comprising: scanning a scan range of the substrate with a sensor, the sensor projecting a beam of radiation on the substrate; measuring the fraction of the intensity of the radiation reflected from different substrate areas along the scan range; determining the variations of the measured fraction across the scan range; determining from the variations whether any defects are present in the substrate.

Abstract: Provided is a method of controlling a fabrication cluster using a machine learning system, the machine learning system trained developed using an optical metrology model. A simulated approximation diffraction signal is generated based on an approximation diffraction model of the structure. A set of difference diffraction signal is obtained by subtracting the simulated approximation diffraction signal from each of simulated fine diffraction signals and paired with the corresponding profile parameters. A first machine learning system is trained using the pairs of difference diffraction signal and corresponding profile parameters. A library of simulated fine diffraction signals and profile parameters is generated using the trained first machine learning system and using ranges and corresponding resolutions of the profile parameters. A measured diffraction signal is input into the trained second machine learning system to determine at least one profile parameter.

Abstract: An optical fiber sensor system includes an optical fiber. A linear polarizing component is configured to communicate with the optical fiber. The linear polarizing component includes a polarization sensing fiber to be disposed adjacent to and preferably collinear with the optical fiber. A light source communicates with the linear polarizing component for generating a light signal along the optical fiber. A reflector is disposed along the optical fiber for reflecting back the light signal along the optical fiber. An optical detector communicates with the linear polarizing component. A signal processor communicating with the optical detector and configured for determining from the reflected light signal dynamic events along the optical fiber.

Abstract: Ellipsometry systems for imaging binding events between analytes in a sample and an array of ligands in an evanescent field generated by a beam of light reflected from the plane of the ligands is adapted to a multiwell plate structure in common use. In one example, a film of prism arrays is affixed to the underside of the plate with each prism array located in registry with a well and ligand arrays being immobilized on the (planar) bottom surface of the wells. The prism array may be formed in a film and juxtaposed with the bottom surface of the plate or a prism array can be made integral with the plate bottom of a multiwell plate.

Abstract: A spectroscopic system for adjusting spacing between an adjacent source/detector as a unit, and a sample, and a reflecting means for directing an incident beam which reflects from said sample back onto said sample and then into the detector along a locus which is in a plane of incidence that is offset from that of the incident beam, or directly from the reflecting means into the detector, including means for reducing reflections of a beam of electromagnetic from the back of a sample, including methodology of use.

Abstract: To effectively reduce a measurement error in a parameter indicating a state of spectroscopic polarization generated by variations in retardation of a retarder due to a temperature change or other factors, while holding a variety of properties of a channeled spectroscopic polarimeter. By noting that reference phase functions ?1(?) and ?2(?) are obtained by solving an equation from each vibration component contained in a channeled spectrum P(?), the reference phase functions ?1(?) and ?2(?) are calibrated concurrently with measurement of spectrometric Stokes parameters S0(?), S1(?), S2(?), and S3(?).

Abstract: Various systems for measurement of a specimen are provided. One system includes an optical subsystem configured to perform measurements of a specimen using vacuum ultraviolet light and non-vacuum ultraviolet light. This system also includes a purging subsystem that is configured to maintain a purged environment around the optical subsystem during the measurements. Another system includes a cleaning subsystem configured to remove contaminants from a specimen prior to measurement. In one embodiment, the cleaning subsystem may be a laser-based cleaning subsystem that is configured to remove contaminants from a localized area on the specimen. The system also includes an optical subsystem that is configured to perform measurements of the specimen using vacuum ultraviolet light. The optical subsystem is disposed within a purged environment. In some embodiments, the system may include a differential purging subsystem that is configured to provide the purged environment for the optical subsystem.

Abstract: A system and method which reduces change in locus of a beam of electromagnetic radiation which otherwise result from vibrations caused by operation of a motor which controls the rotation of an element which affects the beam.

Abstract: A sample information obtaining apparatus includes an electromagnetic wave generator; a sample holding unit which holds a sample to be tested and serves as a polarizer having a polarization axis which defines how an incident electromagnetic wave is to be divided according to a polarization state of the incident electromagnetic wave; an electromagnetic wave detecting unit which separately detects a transmitted electromagnetic wave transmitted through the sample holding unit and a reflected electromagnetic wave reflected off the sample holding unit, the transmitted and reflected electromagnetic waves being obtained by dividing the incident electromagnetic wave incident on the sample holding unit according to a relative positional relationship between the polarization state of the incident electromagnetic wave and the polarization axis of the sample holding unit; and a processor which processes signals of the electromagnetic waves detected by the electromagnetic wave detecting unit and obtains information about t

Abstract: A grating-based biosensor is disclosed where the biosensor is constructed and arranged such that the grating lines of the sensor align with an optical axis of a birefringent substrate, so as to improve resonance peak uniformity. Methods of manufacturing biosensors to provide alignment of the grating lines with the optical axes of a birefringent substrate are also disclosed. One embodiment uses a grating master wafer to form a grating on a continuous web of substrate material. The grating master wafer is rotated relative to the web until the lines of the grating in the master wafer are in substantial alignment with the optical axis of the web. A UV curable material is applied to the wafer and cured in place to form the grating on the surface of the substrate web. With a web of some preferred materials, such as PET film, one need only determine the optical axis orientation once for a given web since the optical axis orientation is essentially constant along the length of the web.

Abstract: A system for monitoring thin-film fabrication processes is herein disclosed. Diffraction of incident light is measured and the results are compared to a predictive model based on at least one idealized or nominal structure. The model and/or the measurement of diffracted incident light may be modified using the output of one or more additional metrology systems.

Abstract: An apparatus and method for laser probing of a DUT at very high temporal resolution is disclosed. The system includes a CW laser source, a beam optics designed to point two orthogonally polarized beams at the same location on the DUT, optical detectors for detecting the reflected beams, collection electronics, and an oscilloscope. The beam optics defines a common-path polarization differential probing (PDP) optics. The common-path PDP optics divides the laser beam into two beams of orthogonal polarization. Due to the intrinsic asymmetry of a CMOS transistor, the interaction of the beams with the DUT result in different phase modulation in each beam. This difference can be investigated to study the response of the DUT to the stimulus signal.

Abstract: A rotating compensator spectroscopic ellipsometer or polarimeter system having a source of a polychromatic beam of electromagnetic radiation, a polarizer, a stage for supporting a material system, an analyzer, a dispersive optics and a detector system which comprises a multiplicity of detector elements, the system being functionally present in an environmental control chamber and therefore suitable for application in wide spectral range, (for example, 130-1700 nm). Preferred compensator design involves a substantially achromatic multiple element compensator systems wherein multiple total internal reflections enter retardance into an entered beam of electromagnetic radiation, and the elements thereof are oriented to minimize changes in the net retardance vs. the input beam angle resulting from changes in the position and/or rotation of the system of elements.

Abstract: The accuracy of a library of simulated-diffraction signals for use in optical metrology of a structure formed on a wafer is evaluated by utilizing an identity relationship inherent to simulated diffraction signals. Each simulated diffraction signal contains at least one set of four reflectivity parameters for a wavelength and/or angle of incidence. One of the four reflectivity parameters is selected. A value for the selected reflectivity parameter is determined using the identity relationship and values of the remaining three reflectivity parameters. The determined value for the selected reflectivity parameter is compared to the value in the obtained set of four reflectivity parameters to evaluate and improve the accuracy of the library. The identity relationship can also be used to reduce the data storage in a library.

Abstract: An optical coupling apparatus for a dual column charged particle beam tool allowing both optical imaging of an area of an integrated circuit, as well as localized heating of the integrated circuit to form silicide. In one embodiment, optical paths from a whitelight source and a laser source are coupled together by way of first and second beam splitters so that a single optical port of the dual column tool may be utilized for both imaging and heating. In another embodiment, a single laser source is employed to provide both illumination for standard microscopy-type imaging, as well as localized heating. In a third embodiment, a single laser source provides heating along with localized illumination for confocal scanning microscopy-type imaging.

Abstract: A method, apparatus, and computer program product for identifying features in a sample by analyzing Mueller matrices to calculate an average degree of polarization, a weighted average degree of polarization, a degree of polarization map, a degree of polarization surface. Also, a method, apparatus, and computer program product for identifying features in a sample by analyzing Mueller matrices to calculate depolarization relative to a retardance axis and/or a diattentuation axis, and to calculate a ratio of diattenuation to polarizance or ratios of row and column magnitudes. Also, a method for retinal polarimetry, including a non-depolarizing light tube configured for insertion into the eye.

Abstract: Disclosed herein are portable and modular detection devices and systems for detecting electromagnetic radiation, such as fluorescence, from an analyte which comprises at least one optical element removably attached to at least one alignment rail. Also disclosed are modular detection devices and systems having an integrated lock-in amplifier and spatial filter and assay methods using the portable and modular detection devices.

Abstract: This application describes designs, implementations, and techniques for controlling propagation mode or modes of light in a common optical path, which may include one or more waveguides, to sense a sample.

Abstract: One or more profile parameters of a structure fabricated on a wafer in a wafer application are determined by developing a correlation between a set of profile models and one or more key profile shape variables. The wafer application has one or more process steps and one or more process parameters. Each profile model is defined using a set of profile parameters to characterize the shape of the structure. Different sets of profile parameters define the profile models in the set. The one or more key profile shape variables include one or more profile parameters or one or more process parameters. A value of at least one key profile shape variable of the process step of the wafer application to be used in fabricating the structure is determined. One profile model is selected from the set of profile models based on the determined correlation and the value of the at least one determined key profile shape variable.

Abstract: The invention relates to a method for determining and/or evaluating a differential, optical signal. According to the invention, at least two first light sources (S1, S2) which are sequentially clocked in terms of light and emitted in a phased manner are provided, in addition to at least one receiver (E) which is used to receive at least the alternating light portion arising from the first light sources (S1, S2). The light intensity radiating through at least one light source (S1, S2) in the measuring arrangement is controlled in such a manner that the clock synchronous alternating light portion, which occurs between different phases, is zero in the receiver (E). By determining the reception signal in the receiver (E) in relation to the phase position in order to regulate the radiated light intensity and by producing an adjustable variable (R) directly or by adding current in the receiver, it is possible to simplify digital implementation of the method with as little sensitivity loss as possible.

Abstract: A spectroscopic ellipsometer can compare data different in a measurement condition and facilitate setting an initial value of fitting data even for an inexperienced operator such as a beginner. The spectroscopic ellipsometer includes a reference data storage part storing therein reference data to be compared with measurement data, a conversion operation part converting the measurement data or the reference data into comparable data, so that the measurement data can be compared with the reference data, and a comparison and determination part comparing the measurement data with the reference data made comparable by the conversion operation part with each other and determining a coincidence between the measurement data and the reference data.

Abstract: The profile of a single feature formed on a wafer can be determined by obtaining an optical signature of the single feature using a beam of light focused on the single feature. The obtained optical signature can then be compared to a set of simulated optical signatures, where each simulated optical signature corresponds to a hypothetical profile of the single feature and is modeled based on the hypothetical profile.