KR20130039005A - Three dimensional depth and shape measuring device - Google Patents

Abstract

PURPOSE: A device for measuring a 3D shape and thickness is provided to improve anti-vibration properties when measuring the 3D shape or thickness as errors caused by mechanical movement are reduced. CONSTITUTION: A device(200) for measuring a 3D shape and thickness comprises a white light source(210), a wavelength variable device(220), a first beam splitter(230), a linear polarizer(240), a second beam splitter(280), first and second image acquisition units(290), and a data processing unit. The white light source emits white lights. The wavelength variable device splits the white light incident from the white light source into a plurality of short wavelength lights, and the short wavelength lights are successively emitted per each wavelength. The first beam splitter separates the short wavelength lights into reference lights and measurement light, irradiates the light to a reference mirror(250) and a measurement object(270), and interferes the reference lights and measurement light reflected by the reference mirror and the measurement object, thereby generating coherent lights.

Description

Three dimensional depth and shape measuring device

The present invention relates to a three-dimensional thickness and / or shape measuring device.

In order to detect defects such as flat panel displays, semiconductors, and fine precision parts, it is necessary to inspect the surface of an object and measure three-dimensional thickness and / or shape, and interferometric methods are generally used. It is possible to obtain the thickness and / or solid shape of the object by generating and analyzing the interferometer pattern on the surface of the object to be measured.

One method for this is white light scanning interferometry (WSI). The white light scanning interferometry, which has been actively studied since 1990, has been developed to overcome the phase ambiguity of phase-shifting interferometry and is now measured at several nm resolution even for shapes with large steps of several um. It has the advantage to do it.

The white light scanning interferometry is a term derived from the relative movement by minute intervals in the optical axis direction to obtain an interference signal using white light as illumination.

1 is a conceptual diagram for explaining the basic principle of the white light scanning interference method. Referring to FIG. 1, a white light scanning interferometer including a white light source 10, a light splitter 20, a reference mirror 30, a measurement object 40, and a detector 50 is illustrated.

Such white light scanning interferometers generally use one of Linnik, Michelson, Mirau and Twyman-GreeN methods.

The illumination light (for example, white light) emitted from the white light source 10 is separated into the measurement light and the reference light by the light splitter 20, and the measurement plane (the surface of the measurement object 40) and the reference plane (reference) The surface of the mirror 30). The light reflected from each side generates an interference signal through the same optical path.

The characteristic of such a white light scanning interferometer is to use a short coherence length of white light. A monochromatic light such as a laser can generate an interference signal over several m, but a white light generates an interference signal only within a few um. Use

As shown in FIG. 1, when the measuring object is observed at an interference signal at one measuring point while moving in small intervals in the optical axis direction (z-axis direction), as shown in the figure, the position difference between the measuring point and the reference plane is within a short distance within the interference length. In other words, the interference signal appears only at the point where the measurement path occurs at the same optical path difference as that of the reference plane. Therefore, by acquiring the interference signals for all the measurement points in the measurement area and setting the optical axis direction position at the vertex of each interference signal as the height value, the three-dimensional surface shape of the measurement surface with respect to the reference plane can be measured.

Such a white light scanning interferometer is disclosed in Korean Patent Laid-Open No. 10-2000-0061037.

However, in the case of a white light scanning interferometer, the measurement object has to be moved at a small interval in the direction of the optical axis. Therefore, when measuring the entire area of the flat display substrate, it takes a lot of time and the measurement speed is slow. For example, there is a problem in that the measurement result is inaccurate because it is sensitive to vibration generated by driving in the optical axis direction of the stage on which the measurement object is mounted.

A method that has been tried a lot to overcome this problem is Dispersive White Light Interferometry (DWI) that directly spectroscopically interferes an interference white light signal using a light diffusing device such as a diffraction grating or a prism.

The distributed white light interference method uses a wide spectral bandwidth of white light and spectroscopy the interference signal generated by the optical path difference between the measurement object and the reference plane light for each wavelength, thereby real-time measurement and insensitive to external vibration or environment. The basic principle of distributed white light interference is shown in FIG.

FIG. 2 is a conceptual diagram illustrating the basic principle of the distributed white light interference method, and includes a white light source 110, a light splitter 120, a measurement plane 140, a reference plane 130, a dispersion device 160, and a detector 170. A distributed white light interferometer is shown that includes.

Illumination light (for example, white light) emitted from the white light source 110 is separated into the measurement light and the reference light by the light splitter 120, and is irradiated to the measurement plane 140 and the reference plane 130, respectively. The light reflected from each side generates an interference signal through the same optical path. Here, the reference plane 130 may be a surface of the reference mirror. In this case, the interference signal generated by the optical path difference between the measurement surface 140 and the reference surface 130 is spectrally for each wavelength to obtain distance information on the measurement surface 140.

To this end, a distributed white light interferometer uses a spectrometer composed of, for example, a diffusing device 160 such as a diffraction grating or a prism, and a detector 170 such as a CCD or a CMOS, for example, to spectra a wavelength over a wide band of white light, which is a used light source. To analyze the spectrum. Since there is no need for a separate mechanical driver during this process, there is an advantage that the measurement speed is faster than that of the aforementioned white light scanning interferometer.

Such a distributed white light interferometer is disclosed in Korean Patent Laid-Open Publication No. 10-2006-0052004 and the like, but its structure is complicated and there is a limitation in that the shape and thickness must be measured separately.

Patent Publication 10-2000-0061037 Patent Publication No. 10-2006-0052004

An object of the present invention is to provide a three-dimensional shape and a thickness measuring device capable of measuring a three-dimensional shape by measuring the thickness of the measurement surface or the interference signal between the measurement surface and the reference surface for each wavelength using a wavelength variator having a simple structure. .

In addition, the present invention can scan most of the wavelength region of the light source in a short time, so that mechanical movement of the measurement object is unnecessary, so that the three-dimensional shape and thickness improved vibration resistance characteristics during the three-dimensional thickness and / or shape measurement It is for providing a measuring device.

Another object of the present invention is to provide a three-dimensional shape and a thickness measuring apparatus capable of simultaneously measuring the thickness and the shape of a measurement object using polarization characteristics or wavelength separation methods.

Other objects of the present invention will be readily understood through the following description.

According to an aspect of the present invention, a white light source for irradiating white light, white light incident from the white light source is spectroscopically into a plurality of short wavelength light, the wavelength variable that the plurality of short wavelength light is sequentially emitted for each wavelength, sequentially in the wavelength variable A first light splitter configured to separate the short wavelength light emitted by the reference light into the reference light and the measurement light and to irradiate the reference mirror and the measurement object, respectively, and to interfere with the reference light and the measurement light reflected from the reference mirror and the measurement object to generate interference light; A linear polarizer interposed between the first splitter and the reference mirror, the linear polarizer linearly polarizing the reference light so as to have only the first polarization component, and interfering light emitted from the first optical splitter to the first interference signal and the first polarization A second optical splitter separating the second interference signal for the second polarization component perpendicular to the component, first and second detection signals, respectively; 2. A data processor which generates shape data of a measurement object by signal processing the images acquired by the image acquisition unit and the first image acquisition unit, and generates thickness data of the measurement object by signal processing the image acquired by the second image acquisition unit. Provided is a three-dimensional shape and thickness measurement apparatus comprising a.

The display device may further include a compensating plate interposed between the first light splitter and the measurement object to prevent the measurement light from having a phase difference from the reference light.

The first light splitter may be a general beam splitter, and the second light splitter may be a polarized beam splitter for splitting incident light into light having a first polarization component and a second polarization component. .

The wavelength variator includes a spectroscopic section for spatially separating incident white light into a plurality of short wavelength lights for each wavelength, a short wavelength light selecting section and a short wavelength light selecting section for allowing only one of the plurality of short wavelength lights to continuously proceed and block the progress of the rest. The short wavelength light selected by may be focused to one point, and may include a light collecting part to emit the light along the same output light path.

The spectrometer may include a spectroscopic element for dividing white light into a plurality of short wavelength light having different wavelength bands, and a first cylindrical lens for allowing the plurality of separated short wavelength light to travel in parallel with each other.

The short wavelength light selector may select and advance one by one with respect to the plurality of short wavelength lights. The short wavelength light selection unit includes a plate material perpendicular to the traveling direction of the short wavelength light, and includes a plate formed with a slit through which only one short wavelength light passes at any moment, and the slit is changed in position by rotation or horizontal movement of the plate material. Can be.

The light collecting unit may include a second cylindrical lens for sequentially collecting short wavelength light rays into one point, and a light collecting device for short wavelength light incident at various incident angles to travel along the same output light path.

Meanwhile, according to another aspect of the present invention, a white light source for irradiating white light, a white light incident from the white light source spectroscopically into a plurality of short wavelength light, and in the wavelength variator, the wavelength variator in which a plurality of short wavelength light is sequentially emitted for each wavelength A first light splitter which sequentially emits short-wavelength light into reference light and measurement light and irradiates the reference mirror and the measurement object, and interferes with the reference light and measurement light reflected from the reference mirror and measurement object to generate interference light; Provided by a three-dimensional shape measuring apparatus including an image acquisition unit for detecting an interference signal from the interference light emitted from the first optical splitter and a data processing unit for processing the image obtained by the image acquisition unit to generate shape data of the measurement object do.

Meanwhile, according to another aspect of the present invention, a white light source for irradiating white light and a white light incident from the white light source are spectroscopically divided into a plurality of short wavelength light, and a plurality of short wavelength light is sequentially emitted for each wavelength, the wavelength variable variable A light splitter which emits short-wavelength light sequentially emitted from the measurement object to the measurement object with the measurement light, and generates an interference light by interfering the measurement light reflected from the measurement object, and an image detecting the interference signal from the interference light emitted from the light splitter. Provided is a three-dimensional thickness measuring apparatus including a data processing unit for generating thickness data of a measurement object by signal processing an image acquired by an acquisition unit and an image acquisition unit.

Meanwhile, according to another aspect of the present invention, a white light source for irradiating white light and a white light incident from the white light source are spectroscopically divided into a plurality of short wavelength light, and a plurality of short wavelength light is sequentially emitted for each wavelength, the wavelength variable variable The first light splitter which generates short-wavelength light sequentially emitted from the light beam is separated into the reference light and the measurement light and irradiated to the reference mirror and the measurement object, respectively, and interferes with the reference light and the measurement light reflected from the reference mirror and the measurement object. A wavelength divider interposed between the first light splitter and the reference mirror and passing only the short wavelength light belonging to the first wavelength region of the reference light, and the interference light emitted from the first light splitter and the first interference signal for the first wavelength region. Each of the second optical splitter, the first interference signal, and the second interference signal are separated into second interference signals for the remaining wavelength regions except for the first wavelength region. Signal processing is performed on the first and second image acquisition units and the images acquired by the first image acquisition unit to generate the shape data of the measurement object, and the image obtained by the second image acquisition unit is signal processed to Provided is a three-dimensional shape and thickness measurement apparatus including a data processor for generating thickness data.

The wavelength divider may be a shutter that allows the progress of the reference light only for a predetermined time during the variable wavelength period.

Alternatively, the wavelength splitter may be a filter that passes only the first wavelength region among all wavelength regions to which the plurality of short wavelength light belongs. The filter may be one of a high pass filter, a low pass filter, and a band pass filter.

Other aspects, features, and advantages will become apparent from the following drawings, claims, and detailed description of the invention.

According to a preferred embodiment of the present invention, it is possible to measure the three-dimensional shape by measuring the thickness of the measurement plane or the interference signal between the measurement plane and the reference plane for each wavelength using a wavelength variator having a simple structure.

In addition, since most wavelength regions of the light source can be scanned in a short time, mechanical movement of the measurement object becomes unnecessary, so that the occurrence of errors due to mechanical movement is reduced, thereby improving vibration resistance characteristics when measuring three-dimensional thickness and / or shape. It is effective.

In addition, only vertically polarized light (or horizontally polarized light) is irradiated to the reference plane, and both vertical and horizontal polarized light are irradiated to the measurement plane, and the interference signal is divided into vertically polarized light and horizontally polarized light to detect the polarized light. There is an effect that can measure the thickness and shape at the same time.

In addition, by using a shutter or a filter to separate the entire wavelength range of the variable by the wavelength variable into two areas to pass the wavelength of only one region to the reference plane by using the wavelength separation method to determine the thickness and shape of the measurement object There is an effect that can be measured at the same time.

1 is a conceptual diagram illustrating a basic principle of a white light scanning interference method;
2 is a conceptual diagram illustrating a basic principle of the distributed white light interference method;
3 is a three-dimensional perspective view showing a schematic configuration of a three-dimensional shape and thickness measurement apparatus according to an embodiment of the present invention,
4 is a front view of the three-dimensional shape and thickness measurement apparatus shown in FIG.
5 is a three-dimensional perspective view showing a schematic configuration of a wavelength variable included in the three-dimensional shape and thickness measurement apparatus according to an embodiment of the present invention,
6 is a three-dimensional perspective view showing a schematic configuration of a three-dimensional shape measuring apparatus according to another embodiment of the present invention,
7 is a front view of the three-dimensional shape measuring apparatus shown in FIG.
8 is a three-dimensional perspective view showing a schematic configuration of a three-dimensional thickness measuring apparatus according to another embodiment of the present invention;
9 is a front view of the three-dimensional thickness measuring device shown in FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Referring to the accompanying drawings, the same or corresponding components are denoted by the same reference numerals, .

Figure 3 is a three-dimensional perspective view showing a schematic configuration of a three-dimensional shape and thickness measuring apparatus according to an embodiment of the present invention, Figure 4 is a front view of the three-dimensional shape and thickness measuring apparatus shown in Figure 3, Figure 5 3D is a perspective view showing a schematic configuration of a wavelength variable included in the three-dimensional shape and thickness measurement apparatus according to an embodiment of the present invention. 3 and 4, the three-dimensional shape and thickness measurement apparatus 200, the white light source 210, the collimating lens 215, the wavelength variabler 220, the first and second light splitters 230 and 280. ), The linear polarizer 240, the first and second objective lenses 255 and 275, the reference mirror 250, the compensation plate 260, the measurement object 270, the first and second image acquisition units 290, 295 is shown.

In the three-dimensional shape and thickness measurement apparatus 200 according to the present embodiment, a plurality of short wavelength light beams separated by wavelengths using a white light source and a wavelength variable are sequentially incident into an interferometer, irradiated onto a reference plane and a measurement plane, and the reflected light By interfering, the thickness and surface shape of the measurement object are measured in three dimensions. According to this, since white light is classified by wavelength and is incident on the interferometer, it is not necessary to move the measuring object mechanically as in the conventional three-dimensional measurement, so that the occurrence of errors due to vibration due to mechanical movement is reduced, thereby the vibration resistance characteristics in the measurement process. This has the feature of being improved.

In addition, since the short wavelength light is irradiated to the measurement surface as it is, but the short wavelength light polarized in one direction is irradiated to the reference surface, the one-way polarization component of the interfering light includes shape information due to the difference between the reference plane and the measurement plane, It includes the thickness information on the measurement surface is characterized in that the thickness and shape of the measurement object can be measured at the same time.

The three-dimensional shape and thickness measurement apparatus 200 according to the present embodiment is a white light source 210, a wavelength variable 220, a first light splitter 230, a linear polarizer 240, a reference mirror 250, measurement The object 270, the second light splitter 280, and the first and second image acquisition units 290 and 295 are used as basic skeletons.

The white light source 210 is a light source for irradiating the illumination light for obtaining data on the thickness and surface shape of the measurement object 270, for example, may be one of a tungsten halogen lamp, xenon lamp, white light emitting diode, etc. The illumination light can be broadband white light, for example.

The white light emitted from the white light source 210 is collimated as parallel light by the collimating lens 215 and is incident to the wavelength variable variable 220.

The wavelength variator 220 spectra the incident white light into a plurality of short wavelength light and emits the light sequentially by wavelength. The configuration and operation of the tunable 220 will be described in detail with reference to the accompanying drawings.

Referring to FIG. 5, the wavelength variable unit 220, the spectroscope 310, the short wavelength light selector 320, the condenser 330, the first and second mirrors 340 and 350, and the spectrometer 311. 1, a first cylindrical lens 313, a plate 321, a slit 323, a light converging irradiation 331, and a second cylindrical lens 333 are illustrated.

The wavelength variable unit 220 includes a spectroscope 310, a short wavelength light selector 320, and a light condenser 330.

The spectroscope 310 spatially separates the white light incident on the wavelength variator 220 for each wavelength. By passing through the spectroscope 310, the white light may be divided by wavelength and proceed at different angles, and the short wavelength light divided by wavelength may be parallel to each other.

To this end, the spectroscope 310 separates the white light into a plurality of short wavelength light having different wavelength bands, and a first cylindrical lens 313 allowing the plurality of short wavelength light to proceed in parallel with each other. ). Here, the spectroscopic element 311 may be, for example, a diffraction grating or a prism. The diffraction grating has a great ability to separate light of wavelengths approaching each other, and may be, for example, one of a flat lattice, a concave lattice, and a stair lattice.

In order to reduce the size of the entire apparatus, a first mirror 340 is interposed in front of the spectroscope 310 in the wavelength tunable 220 so that the optical path of the incident white light may be changed.

The short wavelength light selector 320 selectively travels along the original optical path only for one short wavelength light for the plurality of short wavelength lights spatially separated by the spectroscope 310, and blocks the progress of other short wavelength light.

The short wavelength light selection unit 320 is a plate placed perpendicular to the optical path of the short wavelength light, and at least one slit through which only one short wavelength light passes is formed, and the position of the slit is changed by rotating or horizontally moving the plate. can be changed.

For example, the case where the short wavelength light selection unit 320 is a wheel type slit is illustrated in the drawing. A plurality of slits 323 spaced at predetermined angles are formed at the edge of the disc 321 perpendicular to the optical path of the short wavelength light, and the positions of the slits 323 are changed spatially by rotation of the disc. The short wavelength light sequentially proceeds to the light collecting part 330 at the rear end one by one.

In addition, the short wavelength light selector 320 has slits formed on a flat plate perpendicular to the optical paths of the short wavelength light, and the short wavelength light, which is spatially divided by the horizontal movements of the slits by horizontally moving from side to side, is sequentially one by one. You may also want to proceed to the condenser on the back.

The condenser 330 is a short wavelength light beam having a progressively separated advancing path, which is sequentially selected by the short wavelength light selector 320, and is condensed at one point to form a first light splitter having a rear end along the same output light path. 230).

To this end, the condenser 330 includes a second cylindrical lens 333 for collecting sequentially selected short wavelength light beams at one point, and a condensing device for allowing short wavelength light incident at various incident angles to travel along the same output light path. 331. Here, the light collecting element 331 may be, for example, a diffraction grating or a prism.

The second cylindrical lens 333 may be disposed to be symmetrical with respect to the short wavelength light selector 320 when compared to the first cylindrical lens 313 described above, and the spectroscopic element 311 and the light collecting element ( 331 may also be disposed to be symmetrical with respect to the short wavelength light selection unit 320.

In order to reduce the size of the entire device, a second mirror 350 is interposed at the rear end of the condenser 330 in the wavelength tunable 220 so that the optical path of the short-wavelength light that is finally emitted may be changed.

Referring to FIGS. 3 and 4 again, the first light splitter 230 is a beam splitter that transmits a part of short wavelength light incident from the wavelength variator 220 and reflects the rest in a predetermined direction. In the drawing, the reflected short wavelength light functions as a reference light irradiated to the reference mirror 250, and the transmitted short wavelength light functions as a measurement light irradiated to the measurement object 270 mounted on the stage. This will be described on the assumption. However, the scope of the present invention is not limited thereto, and it is obvious that the transmitted light may function as the reference light and the reflected light may function as the measurement light according to the embodiment.

A linear polarizer 240 is disposed on the optical path of the reference light to linearly polarize the reference light so that the reference light has only one polarization component in one direction (hereinafter, referred to as a first polarization component). For example, the reference light passing through the linear polarizer 240 has only one polarization component of the vertical polarization component or the horizontal polarization component.

In addition, a compensating plate 260 is disposed on the optical path of the measurement light to compensate for a phase difference with the measurement light generated when the reference light passes through the linear polarizer 240.

The first objective lens 255 is disposed on the optical path of the reference light so as to condense the reference light so that the reference light polarized one-way linearly in a predetermined size region on a surface (reference plane) of the reference mirror 250. In addition, the second objective lens 275 is disposed on the optical path of the measurement light to collect the measurement light so that the measurement light is irradiated to a predetermined size region on a surface (measurement surface) of the measurement object 270.

In the present embodiment, the measurement object 270 is mounted on a mechanical feed drive (for example, a stage) so that the measurement area can be changed on the XY plane, but movement in the Z-axis (optical axis) direction is unnecessary. do.

The reference light reflected from the reference mirror 250 (reflected light of the reference plane) is incident again to the first light splitter 230 and is transmitted as it is, and the measurement light reflected from the measurement object 270 (reflected light of the measurement plane) is again the first. The light incident on the light splitter 230 is reflected in the direction in which the reference light is transmitted.

That is, the first light splitter 230 separates the short wavelength light into the reference light and the measurement light, and when the separated reference light and the measurement light are reflected and returned, they interfere with each other to make the interference light.

Here, the reflected light of the reference plane has only the first polarization component (vertical polarization component), and the reflected light of the measurement plane has both the first polarization component and the second polarization component (horizontal polarization component) perpendicular thereto. That is, the first polarization component of the interference light is interference light in which the reflected light of the reference plane and the reflected light of the measurement plane interfere with each other, and the second polarization component is the reflected light of the measurement plane.

The interference light is incident on the second light splitter 280, and is transmitted as it is or is reflected in a predetermined direction according to the polarization component, thereby being separated for each polarization component. For example, the polarization component in one direction (vertical (or horizontal)) that the reference light has due to the linear polarizer 240 passes through as it is, and the polarization component in the other direction (horizontal (or vertical)) is reflected in a predetermined direction. Can be. Or it may be the reverse depending on the nature of the second light splitter 280.

In the present embodiment, the second light splitter 280 may be a polarized beam splitter for separating incident light from each other according to polarization components.

The polarized light component in one direction separated by the second light splitter 280, that is, the interference light of the first polarized light component, is incident on the first image acquisition unit 290, and the polarized light component in the other direction, that is, the second polarized light component The interfering light is incident on the second image acquisition unit 295. Here, the description will be made on the assumption that the first polarization component is a polarization component having the reference light through the linear polarizer 240 as described above, but the scope of the present invention is not limited thereto. The first and / or second image acquisition units 290 and / or 295 may be, for example, cameras of a CCD or CMOS type.

The interference light of the first polarization component is incident on the first image acquisition unit 290 to detect the first interference signal due to the interference between the reference light and the measurement light. This is because both the reference light and the measurement light have the first polarization component. The data processor (not shown) generates shape data on the surface of the measurement object 270 by performing predetermined image processing on the first interference signal detected by the first image acquisition unit 290.

The interference light of the second polarization component is incident on the second image acquisition unit 295 to detect the second interference signal by the measurement light. This is because only the measurement light has the second polarization component, and the reference light passing through the linear polarizer 240 does not have the second polarization component. The data processor generates a thickness data of the thickness of the measurement object 270 by performing a predetermined image processing on the second interference signal detected by the second image acquisition unit 295.

According to the present embodiment, the first polarization component is used to obtain a result of interfering light reflected from the reference plane and the measurement plane, respectively, to obtain information on the surface shape of the measurement object, and the measurement plane is obtained using the second polarization component. Information about the thickness of the measurement object may be obtained from the reflected light. That is, the thickness and the surface shape can be measured at the same time, thereby reducing the measurement time, and there is an advantage in that accurate measurement is not affected by misalignment, time-varying optical characteristics, etc. of the measurement object that can be generated by separate measurement.

In the present embodiment, the white light source 210, the collimating lens 215, the wavelength variator 220, the first light splitter 230, the linear polarizer 240, the first objective lens 255, and the reference mirror 250. , The compensation plate 260, the second objective lens 275, the measurement object 270, the second optical splitter 280, the first image acquisition unit 290, and the second image acquisition unit 295 are optically connected. It is. Optical phenomena include various phenomena such as reflection, diffraction, and refraction of light. Here, 'optically connected' means that light emitted from one component by various optical phenomena is received by the other component. it means.

Or according to the three-dimensional shape and thickness measurement apparatus according to another embodiment of the present invention, the shutter or filter is positioned in place of the linear polarizer 240 with respect to the three-dimensional shape and thickness measurement apparatus 200 shown in FIG.

The shutter or filter functions as a wavelength divider, and when white light is separated for each wavelength by the wavelength variator 220 and is incident on the reference mirror 250, the entire wavelength region is divided into two regions, and among the separated two regions, Only one wavelength region (first wavelength region) is incident on the reference mirror 250.

The shutter allows the light to proceed only for a predetermined time of the variable wavelength period representing the time at which the short wavelength light of the same wavelength is emitted, thereby allowing the predetermined time of the sequential short wavelength light separated by the wavelength variable 220 for each wavelength. Only the short wavelength light emitted from the wavelength variable variable 220 is incident to the reference mirror 250, and the remaining short wavelength light may be blocked from traveling to the reference mirror 250 by the shutter.

In addition, the filter may be one of a high pass filter, a low pass filter, or a band pass filter, and may allow progression to the reference mirror 250 only for short wavelength light beams belonging to a predetermined wavelength region.

In this case, all of the short wavelength light in the entire wavelength range is incident on the measurement object 270.

The interference light reflected from the reference mirror 250 and the measurement object 270 and interfering with the first optical splitter 230 is light in which the reflected light of the reference plane and the reflected light of the measurement plane interfere with each other in the first wavelength region. In the two wavelength region (wavelength region other than the first wavelength region), only the reflected light of the measurement surface exists.

Therefore, the second optical splitter 280 separates the paths so that the interference light belonging to the first wavelength region and the second wavelength region toward different paths according to the wavelength region, and obtains an image according to the interference signal for each By analyzing, information about the shape and thickness of the measurement object can be obtained simultaneously. Here, shape data may be obtained from the interference light corresponding to the first wavelength region, and thickness data may be obtained from the interference light corresponding to the second wavelength region. That is, the thickness and the surface shape can be measured at the same time, thereby reducing the measurement time, and there is an advantage in that accurate measurement is not affected by misalignment, time-varying optical characteristics, etc. of the measurement object that can be generated by separate measurement.

6 is a three-dimensional perspective view showing a schematic configuration of a three-dimensional shape measuring apparatus according to another embodiment of the present invention, Figure 7 is a front view of the three-dimensional shape measuring apparatus shown in FIG. 6 and 7, the three-dimensional shape measuring apparatus 400, the white light source 410, the collimating lens 415, the wavelength variable 420, the light splitter 430, and the first objective lens 455. The reference mirror 450, the second objective lens 475, the measurement object 470, and the image acquisition unit 490 are illustrated.

In the three-dimensional shape measuring apparatus 400 according to the present exemplary embodiment, a plurality of short wavelength light beams divided by wavelengths are sequentially incident on the interferometer, irradiated onto the reference plane and the measurement plane, and the reflected light interferes with each other. The surface shape of the measurement object is measured three-dimensionally. According to this, since white light is classified by wavelength and is incident on the interferometer, it is not necessary to move the measuring object mechanically as in the conventional three-dimensional measurement, so that the occurrence of errors due to vibration due to mechanical movement is reduced, thereby the vibration resistance characteristics in the measurement process. This has the feature of being improved.

The three-dimensional shape measuring apparatus 400 according to the present exemplary embodiment includes a white light source 410, a wavelength variable 420, a light splitter 430, a reference mirror 450, a measurement object 470, and an image acquisition unit 490. ) As the basic skeleton. Compared with the three-dimensional shape and thickness measurement apparatus 200 shown in FIG. 3, the linear polarizer 240, the compensation plate 260, the second optical splitter 280, and the second image acquisition unit 295 are omitted. Having the configuration, the remaining components perform the same or similar functions as the components corresponding to each other shown in FIG.

The white light irradiated from the white light source 410 is collimated by the collimating lens 415 and is incident on the wavelength variator 420 as parallel light, and is divided into a plurality of short wavelength light through the wavelength variator 420 and sequentially emitted. . The operation principle and function of the tunable 420 is the same as the tunable 220 described above with reference to FIG. 5.

The sequential short-wavelength light emitted from the wavelength variator 420 is partially transmitted by the light splitter 430 and the remaining light is reflected in a predetermined direction to pass through the first objective lens 455 and the second objective lens 475. The reference mirror 450 and the measurement object 470 are irradiated with the reference light and the measurement light, respectively.

The reference light and the measurement light reflected from the reference mirror 450 and the measurement object 470 respectively interfere with the light splitter 430 to generate interference light, and the image acquisition unit 490 detects the interference signal of the interference light. .

The data processing unit performs predetermined image processing on the interference signal detected by the image acquisition unit 490 to generate shape data about the surface shape of the measurement object.

In the present embodiment, the white light source 410, the collimating lens 415, the wavelength variable 420, the light splitter 430, the first objective lens 455, the reference mirror 450, and the second objective lens 475. The measurement object 470 and the image acquisition unit 490 are optically connected. Optical phenomena include various phenomena such as reflection, diffraction, and refraction of light. Here, 'optically connected' means that light emitted from one component by various optical phenomena is received by the other component. it means.

8 is a three-dimensional perspective view showing a schematic configuration of a three-dimensional thickness measuring apparatus according to another embodiment of the present invention, Figure 9 is a front view of the three-dimensional thickness measuring apparatus shown in FIG. 8 and 9, the three-dimensional thickness measuring apparatus 500, the white light source 510, the collimating lens 515, the wavelength variable 520, the light splitter 530, and the second objective lens 575. The measurement object 570 and the image acquisition unit 590 are shown.

In the three-dimensional thickness measuring apparatus 500 according to the present embodiment, a plurality of short wavelength light beams, which are classified for each wavelength, are sequentially incident on an interferometer, irradiated onto a measurement surface, and detected by the reflected light using a white light source and a wavelength variable. Measure the thickness of the object. According to this, since white light is classified by wavelength and is incident on the interferometer, it is not necessary to move the measuring object mechanically as in the conventional three-dimensional measurement, so that the occurrence of errors due to vibration due to mechanical movement is reduced, thereby the vibration resistance characteristics in the measurement process. This has the feature of being improved.

The three-dimensional thickness measuring apparatus 500 according to the present exemplary embodiment includes a white light source 510, a wavelength variable 520, a light splitter 530, a measurement object 570, and an image acquisition unit 590 as basic skeletons. . Compared with the three-dimensional shape measuring apparatus 400 shown in FIG. 6, the first objective lens 455 and the reference mirror 450 are omitted, and the remaining components correspond to each other shown in FIG. 6. Perform the same or similar function as the element.

The white light irradiated from the white light source 510 is collimated by the collimating lens 515 and is incident on the wavelength variator 520 as parallel light, and is divided into a plurality of short wavelength light through the wavelength variator 520 and sequentially emitted. . The operation principle and function of the tunable 520 is the same as the tunable 220 described above with reference to FIG. 5.

The sequential short wavelength light emitted from the wavelength variator 520 is irradiated to the measurement object 570 as the measurement light through the light splitter 530 and the second objective lens 575. The measurement light reflected by the measurement object 570 is reflected by the light splitter 530 in a predetermined direction, and the image acquisition unit 590 detects an interference signal of the measurement light.

The data processor performs predetermined image processing on the interference signal detected by the image acquisition unit 590 to generate thickness data about the thickness of the measurement object.

In the present embodiment, the white light source 510, the collimating lens 515, the wavelength variable 520, the light splitter 530, the second objective lens 575, the measurement object 570, and the image acquisition unit 590 Optically connected Optical phenomena include various phenomena such as reflection, diffraction, and refraction of light. Here, 'optically connected' means that light emitted from one component by various optical phenomena is received by the other component. it means.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It will be understood that the invention may be varied and varied without departing from the scope of the invention.

200: three-dimensional shape and thickness measuring device 210, 410, 510: white light source
215, 415, 515: collimating lens 220, 420, 520: wavelength variable
230, 430, 530: first optical splitter 240: linear polarizer
250, 450: reference mirror 255, 455: first objective lens
260: compensation plate 270, 470, 570: measuring object
275, 475, and 575: second objective lens 280: second light splitter
290, 490, and 590: first image acquisition unit 295: second image acquisition unit
400: three-dimensional shape measuring device 500: three-dimensional thickness measuring device
310: spectrometer 320: short wavelength light selection unit
330 condenser

Claims (29)

A white light source for irradiating white light;
A wavelength variator for spectroscopy white light incident from the white light source into a plurality of short wavelength light and sequentially emitting the plurality of short wavelength light for each wavelength;
The short wavelength light sequentially emitted from the wavelength variator is separated into a reference light and a measurement light so as to be irradiated to the reference mirror and the measurement object, and the interference is caused by interfering with the reference light and the measurement light reflected from the reference mirror and the measurement object. A first light splitter for generating light;
A linear polarizer interposed between the first light splitter and the reference mirror and linearly polarize the reference light to have only a first polarization component;
A second optical splitter that separates the interference light emitted from the first optical splitter into a first interference signal for the first polarization component and a second interference signal for a second polarization component perpendicular to the first polarization component;
First and second image acquisition units respectively detecting the first and second interference signals; And
A data processor which generates shape data of the measurement object by signal processing the image acquired by the first image acquisition unit, and generates thickness data of the measurement object by signal processing the image acquired by the second image acquisition unit Three-dimensional shape and thickness measuring apparatus comprising.
The method of claim 1,
And a compensating plate interposed between the first light splitter and the measurement object, such that the measurement light does not have a phase difference from the reference light.
The method of claim 1,
The first light splitter is a general beam splitter, and the second light splitter is a polarized beam splitter for splitting incident light into light having the first polarization component and the second polarization component. 3D shape and thickness measurement apparatus, characterized in that).
The method of claim 1,
The wavelength variable unit,
A spectroscope for spatially separating the incident white light into a plurality of short wavelength light beams for each wavelength;
A short wavelength light selection unit configured to selectively continue only one of the plurality of short wavelength lights and to block the rest of the short wavelength light; And
And a light collecting unit configured to collect the short wavelength light selected by the short wavelength light selecting unit at one point so that the short wavelength light is emitted along the same output light path.
5. The method of claim 4,
The spectroscopic unit includes a spectroscopic element for dividing the white light into the plurality of short wavelength light having different wavelength bands, and a first cylindrical lens for allowing the separated plurality of short wavelength light to travel in parallel with each other. Three-dimensional shape and thickness measuring device.
5. The method of claim 4,
The short wavelength light selection unit is a three-dimensional shape and thickness measuring apparatus, characterized in that for proceeding by selecting the plurality of short wavelength light one by one.
The method according to claim 6,
The short wavelength light selection unit includes a plate material which is perpendicular to the traveling direction of the short wavelength light and has a slit formed therein through which only one short wavelength light passes at any moment.
The slit is a three-dimensional shape and thickness measuring apparatus, characterized in that the position is changed through the rotation or horizontal movement of the plate.
5. The method of claim 4,
The condenser may include a second cylindrical lens for sequentially collecting the short wavelength light rays to be collected at one point, and a light converging element for allowing the short wavelength light incident at various incident angles to travel along the same output light path. A three-dimensional shape and thickness measuring device.
A white light source for irradiating white light;
A wavelength variator for spectroscopy white light incident from the white light source into a plurality of short wavelength light and sequentially emitting the plurality of short wavelength light for each wavelength;
The short wavelength light sequentially emitted from the wavelength variator is separated into a reference light and a measurement light so as to be irradiated to the reference mirror and the measurement object, and the interference is caused by interfering with the reference light and the measurement light reflected from the reference mirror and the measurement object. A first light splitter for generating light;
An image acquisition unit detecting an interference signal from the interference light emitted from the first optical splitter; And
And a data processor configured to signal-process the image acquired by the image acquisition unit to generate shape data of the measurement object.
10. The method of claim 9,
The wavelength variable unit,
A spectroscope for spatially separating the incident white light into a plurality of short wavelength light beams for each wavelength;
A short wavelength light selection unit configured to selectively continue only one of the plurality of short wavelength lights and to block the rest of the short wavelength light; And
And a light collecting unit configured to collect the short wavelength light selected by the short wavelength light selecting unit at one point and output the same along the same output light path.
The method of claim 10,
The spectroscopic unit includes a spectroscopic element for dividing the white light into the plurality of short wavelength light having different wavelength bands, and a first cylindrical lens for allowing the separated plurality of short wavelength light to travel in parallel with each other. Three-dimensional shape measuring device.
The method of claim 10,
And the short wavelength light selection unit selects and advances the plurality of short wavelength light one by one sequentially.
The method of claim 12,
The short wavelength light selection unit includes a plate material which is perpendicular to the traveling direction of the short wavelength light and has a slit formed therein through which only one short wavelength light passes at any moment.
The slit is a three-dimensional shape measuring apparatus, characterized in that the position is changed through the rotation or horizontal movement of the plate.
The method of claim 10,
The condenser may include a second cylindrical lens for sequentially collecting the short wavelength light rays to be collected at one point, and a light converging element for allowing the short wavelength light incident at various incident angles to travel along the same output light path. A three-dimensional shape measuring device.
A white light source for irradiating white light;
A wavelength variator for spectroscopy white light incident from the white light source into a plurality of short wavelength light and sequentially emitting the plurality of short wavelength light for each wavelength;
An optical splitter configured to irradiate short-wavelength light sequentially emitted from the wavelength variable to the measurement object with measurement light and to interfere with the measurement light reflected from the measurement object to generate interference light;
An image acquisition unit detecting an interference signal from the interference light emitted from the optical splitter; And
And a data processor configured to signal-process the image acquired by the image acquisition unit to generate thickness data of the measurement object.
16. The method of claim 15,
The wavelength variable unit,
A spectroscope for spatially separating the incident white light into a plurality of short wavelength light beams for each wavelength;
A short wavelength light selection unit configured to selectively continue only one of the plurality of short wavelength lights and to block the rest of the short wavelength light; And
And a light concentrator configured to condense the short wavelength light selected by the short wavelength light selector into one point and output the light along the same output light path.
17. The method of claim 16,
The spectroscopic unit includes a spectroscopic element for dividing the white light into the plurality of short wavelength light having different wavelength bands, and a first cylindrical lens for allowing the separated plurality of short wavelength light to travel in parallel with each other. Three-dimensional thickness measuring device.
17. The method of claim 16,
The short wavelength light selecting unit is a three-dimensional thickness measuring apparatus, characterized in that for selecting the plurality of short wavelength light sequentially to advance.
19. The method of claim 18,
The short wavelength light selection unit includes a plate material which is perpendicular to the traveling direction of the short wavelength light and has a slit formed therein through which only one short wavelength light passes at any moment.
The slit is a three-dimensional thickness measuring device, characterized in that the position is changed through the rotation or horizontal movement of the plate.
17. The method of claim 16,
The condenser may include a second cylindrical lens for sequentially collecting the short wavelength light rays to be collected at one point, and a light converging element for allowing the short wavelength light incident at various incident angles to travel along the same output light path. Three-dimensional thickness measurement device characterized in that.
A white light source for irradiating white light;
A wavelength variator for spectroscopy white light incident from the white light source into a plurality of short wavelength light and sequentially emitting the plurality of short wavelength light for each wavelength;
The short wavelength light sequentially emitted from the wavelength variator is separated into a reference light and a measurement light so as to be irradiated to the reference mirror and the measurement object, and the interference is caused by interfering with the reference light and the measurement light reflected from the reference mirror and the measurement object. A first light splitter for generating light;
A wavelength divider interposed between the first light splitter and the reference mirror and configured to pass only short wavelength light belonging to a first wavelength region of the reference light;
A second optical splitter that separates the interference light emitted from the first optical splitter into a first interference signal for the first wavelength region and a second interference signal for the remaining wavelength region except for the first wavelength region;
First and second image acquisition units respectively detecting the first and second interference signals; And
A data processor which generates shape data of the measurement object by signal processing the image acquired by the first image acquisition unit, and generates thickness data of the measurement object by signal processing the image acquired by the second image acquisition unit Three-dimensional shape and thickness measuring apparatus comprising.
The method of claim 21,
The wavelength divider is a three-dimensional shape and thickness measurement apparatus, characterized in that the shutter allows the progress of the reference light only for a predetermined time of the variable wavelength period.
The method of claim 21,
The wavelength divider is a three-dimensional shape and thickness measuring device, characterized in that the filter for passing only the first wavelength region of the entire wavelength region to which the plurality of short wavelength light belongs.
24. The method of claim 23,
And the filter is one of a high pass filter, a low pass filter, and a band pass filter.
The method of claim 21,
The wavelength variable unit,
A spectroscope for spatially separating the incident white light into a plurality of short wavelength light beams for each wavelength;
A short wavelength light selection unit configured to selectively continue only one of the plurality of short wavelength lights and to block the rest of the short wavelength light; And
And a light collecting unit configured to collect the short wavelength light selected by the short wavelength light selecting unit at one point so that the short wavelength light is emitted along the same output light path.
26. The method of claim 25,
The spectroscopic unit includes a spectroscopic element for dividing the white light into the plurality of short wavelength light having different wavelength bands, and a first cylindrical lens for allowing the separated plurality of short wavelength light to travel in parallel with each other. Three-dimensional shape and thickness measuring device.
26. The method of claim 25,
The short wavelength light selection unit is a three-dimensional shape and thickness measuring apparatus, characterized in that for proceeding by selecting the plurality of short wavelength light one by one.
28. The method of claim 27,
The short wavelength light selection unit includes a plate material which is perpendicular to the traveling direction of the short wavelength light and has a slit formed therein through which only one short wavelength light passes at any moment.
The slit is a three-dimensional shape and thickness measuring apparatus, characterized in that the position is changed through the rotation or horizontal movement of the plate.
26. The method of claim 25,
The condenser may include a second cylindrical lens for sequentially collecting the short wavelength light rays to be collected at one point, and a light converging element for allowing the short wavelength light incident at various incident angles to travel along the same output light path. A three-dimensional shape and thickness measuring device.

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