KR101415857B1 - Device of inspecting sample's surface - Google Patents

Abstract

The surface shape inspection apparatus of the present invention is for inspecting the surface shape of an object to be inspected and includes a light source section, an optical distributor, a partial reflection film, a supporting section, a driving section and a sensing section. The light source unit sequentially scans a plurality of wavelengths to emit light whose wavelength variation is repeated, and the light distribution unit transmits light from the light source unit in a direction in which the object to be inspected is located. The partial reflection film reflects the first light, which is a part of the light from the light distribution part, and the support part supports the object to be inspected so that the second light not reflected by the partial reflection film among the light from the light distribution part is reflected from the object to be inspected. The driving unit adjusts the position of at least one of the partial reflective film and the supporting part such that the distance between the partial reflective film and the supporting part is smaller than the coherence length so that interference can be caused by the path difference between the first light and the second light . The sensing unit receives the first light and the second light for generating the interference signal, and acquires information about the surface shape of the object to be inspected through the interference signal. Therefore, the surface shape inspection apparatus can acquire the surface shape information of the large-area inspection object at a high resolution in a short time.

Description

DEVICE OF INSPECTING SAMPLE 'SURFACE "

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface shape inspection apparatus, and more particularly, to a surface shape inspection apparatus capable of acquiring high resolution information in a short time with respect to a surface shape of a large-area inspection object.

The measurement system using the central wavelength scan variable of the light is intended to overcome the disadvantage of the conventional white light scanning interferometry (WSI), which is a device for obtaining the surface shape of the sample by using the coherence phenomenon of light.

The white light scanning interferometer is a high resolution imaging system capable of acquiring surface shape information of a sample. The white light scanning interferometer is an apparatus using the interference distance of the visible light and near infrared ray wavelength light source. Particularly, the white light scanning interferometer is an imaging technique for non-contacting the surface of a sample, and studies related thereto have been actively conducted.

However, in order to obtain a three-dimensional surface shape using a two-dimensional CCD (Cd) in the white light scanning interferometer, a path difference of traveling light must be generated. For this, the acquisition of depth direction information is limited by the limit of the repetitive transfer rate of the fixed reference mirror over time and the limitation of the mechanical optical path difference repetition stability.

On the other hand, in the dispersive white light scanning interferometer (Dispersive WSI), by using one axis of the two-dimensional CCD for obtaining spectroscopic information, the optical path difference information can be obtained without repetitive transfer of the reference end.

However, in a dispersive white light scanning interferometer (Dispersive WSI), the light exposed to the surface must be scanned to the horizontal axis or the vertical axis to obtain the final three-dimensional surface shape. Therefore, when a large-area scanning is performed, there arises a problem that the scanning speed of the horizontal axis and the vertical axis significantly lowers the information acquisition rate of the sample.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a problem, and it is an object of the present invention to provide a laser apparatus which uses a laser capable of obtaining optical interference information by varying a central wavelength with time, Or a surface shape of the object to be inspected to enlarge the surface of the object to be inspected in a large area so as to acquire information on the surface shape.

The surface shape inspection apparatus according to embodiments of the present invention is for inspecting the surface shape of an object to be inspected and includes a light source unit, a partial reflection film, a supporting unit, a driving unit, and a sensing unit. The light source sequentially scans a plurality of wavelengths and emits light whose wavelength tuning is repeated. The partial reflection film reflects the first light, which is a part of the light from the light source part. The support part supports the object to be inspected such that a second light among the lights from the light source part, which is not reflected by the partial reflection film, is reflected by the object to be inspected. Wherein the driving unit is formed to have a distance smaller than a coherence length of the partial reflection film and the supporting unit so that interference can occur due to a path difference between the first light and the second light, The position of at least one of the partial reflection film and the supporting portion is adjusted so that the portions are positioned parallel to each other. The sensing unit receives the first light and the second light for generating an interference signal, and acquires information about the surface shape of the object to be inspected through the interference signal.

The surface shape inspection apparatus according to another embodiment of the present invention is for inspecting the surface shape of an object to be inspected and includes a light source portion, a partial reflection film, a supporting portion, a driving portion, and a sensing portion. The light source sequentially scans a plurality of wavelengths and emits light whose wavelength tuning is repeated. The partial reflection film reflects the first light that is a part of the lights from the light source unit. The support part supports the object to be inspected such that a second light among the lights from the light source part, which is not reflected by the partial reflection film, is reflected by the object to be inspected. Wherein the driving unit is configured to adjust the distance between the partial reflection film and the supporting unit to be smaller than the optical coherence length so that interference can be generated by the difference in path between the first light and the second light, At least one of them. The sensing unit receives the first light and the second light for generating an interference signal, and acquires information about the surface shape of the object to be inspected through the interference signal.

In the embodiments of the present invention, the light distribution unit may further include an optical distributor for transmitting the light from the light source in a direction in which the inspected object is located.

The surface of the partial reflection film is coated with a material capable of adjusting the reflectance and reflection position of light. The surface of the partial reflection film facing the inspection object may be coated with a material that suppresses reflection of light.

In the embodiments of the present invention, when the sensing unit primarily recognizes the area smaller than the size of the inspected object, after the sensing unit acquires the surface shape information of the inspected object using the interference signal, The position of the support can be adjusted to sense the surface shape of the remaining area of the inspection object that the sensing unit has not sensed.

In the embodiments of the present invention, when the sensing unit primarily recognizes the area smaller than the size of the inspected object, the sensing unit first obtains the surface shape information of the inspected object using the interference signal A position of at least one of the light source section, the partial reflection film, the light distribution section, and the sensing section is fixed while the position of the inspection object is fixed in order to detect the surface shape of the remaining area of the inspection object, Can be adjusted.

In the embodiments of the present invention, the surface shape inspection apparatus is disposed between the light source unit and the optical distribution unit, and the light emitted from the light source unit is expanded in a line shape or a surface shape corresponding to the size of the inspection object, A second optical system located between the optical distributor and the partial reflection film for spatially expanding the light from the optical distributor in the shape of a line or a shape corresponding to the size of the inspected object, And a third optical system positioned between the optical distributor and the sensing unit and for expanding the light reflected from the partial reflection film and the inspected object and passing through the optical distributor in the form of a line or a space have.

In the embodiments of the present invention, when the inspection object is composed of a plurality of layers, the third light not reflected from the surface of the inspection object among the light not reflected by the partial reflection film is located below the surface of the inspection object Is reflected at the surface of at least one of the layers. At this time, the driving unit may adjust the position of at least one of the partial reflection film and the supporting unit such that the distance between the partial reflection film and the surface on which the third light is reflected is smaller than the interference distance of the light.

In the embodiments of the present invention, the support portion may include a first support for supporting the lower portion of the object to be inspected by placing the object to be inspected, and a columnar body positioned at the edge of the support and higher than the height of the object to be inspected And a second support of a second support. The driving unit may adjust the position of at least one of the partial reflective film and the supporting unit such that a bottom edge of the partial reflective film is in contact with an upper surface of the second supporting unit.

In the embodiments of the present invention, the sensing unit senses the surface shape of the object to be inspected through the interference signal generated by the path difference between the first light and the second light to correspond to each position of the surface of the object to be inspected It detects pixel by pixel.

In the embodiments of the present invention, the sensing unit Fourier transforms the interference signal having a periodic light intensity change by scanning a center wavelength to acquire a spectrum signal corresponding to the period value.

The surface shape inspection apparatus as described above has the following effects.

First, since the distance between the partial reflection film and the object to be inspected is smaller than the interference distance of the light from the light source, light reflected from the partial reflection film and the object to be inspected interfere with each other and the surface shape information of the object to be inspected can be obtained have.

Secondly, by expanding the light emitted from the light source in a plane shape or a line shape, it is possible to efficiently acquire the surface shape of a large-area inspection object in a short period of time.

Thirdly, by adjusting the position of the partial reflecting film and the support for supporting the inspection object so that the distance between the partial reflection film and the inspection object is kept smaller than the optical interference distance, the surface shape information of the inspection object can be obtained in a stable environment.

Fourth, since the optical interference signal can be generated by sequentially scanning the center wavelength of the light source instead of changing the position of the partial reflection film on which the light is reflected, the surface shape information of the object to be inspected in real time Can be obtained.

Fifth, not only the surface shape of the object to be inspected, but also the shape information of the reflection surface inside the surface of the object to be inspected can be obtained.

1 is a schematic configuration diagram of a surface shape inspection apparatus according to embodiments of the present invention
[Fig. 2] is a view for explaining the phenomenon of interference due to the optical path difference by reflecting light on the partial reflection film and the surface of the inspection object shown in Fig. 1, respectively
3 is a view for explaining an example of adjusting the position of the partial reflective film and the supporting portion shown in Fig. 1
4 is a view for explaining an interference signal received by the sensing unit shown in FIG. 1 and a spectrum signal corresponding thereto; FIG.
5A and 5B are views for explaining the result of acquiring the surface shape information according to the embodiments of the present invention,

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A surface shape inspection apparatus according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It is to be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Like reference numerals are used for like elements in describing each drawing. In the accompanying drawings, the dimensions of the structures are enlarged to illustrate the present invention, and are actually shown in a smaller scale than the actual dimensions in order to understand the schematic structure.

Also, the terms first and 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. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. On the other hand, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic configuration diagram of a surface shape inspection apparatus according to embodiments of the present invention. FIG.

Referring to FIG. 1, the surface shape inspection apparatus according to embodiments of the present invention grasps the shape of the surface of the object to be inspected 130 using the interference phenomenon of light, and performs a surface inspection using the shape of the object. The surface shape inspection apparatus includes a light source 100, an optical distributor 110, a partial reflection film 120, a support 131, and a sensing unit 140.

The light source unit 100 sequentially scans a plurality of wavelengths and emits light whose wavelength tuning is repeated. For example, the light source unit 100 includes a laser capable of obtaining optical interference information by varying the central wavelength of the scan signal according to time.

The light distribution unit 110 transmits light emitted from the light source unit 100 in a direction in which the object to be inspected 130 is located. For example, when the inspection object 130 is not positioned on the straight path of the light emitted from the light source unit 100, the light distribution unit 110 changes the path of the light emitted from the light source unit 100, 130 are located. Alternatively, when the object to be inspected 130 is located on a linear path of light emitted from the light source unit 100, the light distribution unit 110 may pass light.

The optical distributor 110 directs the light reflected from the partial reflection film 120 and the inspection object 130 to the direction in which the sensing unit 140 is positioned. At this time, the optical distributor 110 causes the light reflected from the partial reflection film 120 and the inspection object 130 to be combined with the axis of the sensing unit 140.

The partial reflection film 120 reflects the first light, which is a part of the lights from the light distribution section 110. That is, the partial reflection film 120 reflects the first light, which is a part of the light passing through the optical distributor 110, and passes the remaining light except for the first light so as to be directed toward the object to be inspected 130.

In the embodiments of the present invention, the surface of the partial reflective film 120 may be coated with a material capable of adjusting the reflectance and reflection position of light. In addition, the surface of the partial reflection film 120 facing the object to be inspected 130 may be coated with a material that suppresses reflection of light.

That is, the partial reflection film 120 is coated with a material having a high reflectance on the surface for reflecting the first light, and the light reflected from the object to be inspected 130 is transmitted to the opposite surface, So that it can be coated with a material having a low reflectance or little reflectance.

The supporting portion 131 supports the object to be inspected 130. For example, the support portion 131 has an area larger than that of the object to be inspected 130 in order to stably support the object 130 to be inspected. In the embodiments of the present invention, among the light beams passing through the optical distributor 110 from the surface of the object to be inspected 130 supported by the supporter 131, the second light not reflected by the partial reflection film 120 is reflected do.

Therefore, a difference between the path of the first light reflected by the partial reflection film 120 and the path of the second light reflected by the inspection object 130 among the light emitted from the light source unit 100 occurs. At this time, if the path difference between the first light and the second light is smaller than the coherence length of the light, an interference phenomenon may occur between the first light and the second light. In other words, the difference between the first time required for the first light to propagate and the second required time for the second light to propagate becomes smaller than the coherence time of the light, It is possible to generate this interference signal.

The sensing unit 140 receives the first light and the second light to generate an interference signal. Accordingly, the sensing unit 140 can acquire information on the surface shape of the object to be inspected 130 through the interference signal. In particular, the sensing unit 140 can sense the surface shape of the object to be inspected 130 for each pixel corresponding to each position on the surface of the object to be inspected 130 through the interference signal. For example, the sensing unit 140 may be equipped with various types of photographing equipment having a camera function.

The portion in which the sensing unit 140 acquires information about the surface shape through the interference signal will be described in detail with reference to FIG. 4 and FIG.

The driving unit 180 drives the partial reflective film 120 and the supporting unit 131 to adjust the position and attitude thereof. The driving unit 180 may include a first driving unit 181 for controlling the position of the partial reflective film and a second driving unit 182 for controlling the position of the supporting unit 131.

In the embodiments of the present invention, in order to cause an interference phenomenon between the first light and the second light, the driving unit 180 may be configured such that the path difference between the first light and the second light is smaller than the coherence length of the light The position of at least one of the partial reflection film 120 and the support 131 can be adjusted. For example, when the first driving unit 181 adjusts the position of the partial reflective film 120 so that the interval between the partial reflective film 120 and the supporting unit 131 is smaller than the interference distance of the light, The distance between the partial reflection film 120 and the support part 131 can be made smaller than the interference distance of the light by adjusting the position of the support part 131. [ Further, the positions of the partial reflective film 120 and the support portion 131 can be controlled simultaneously or sequentially by the first driving portion 181 and the second driving portion 182.

 The driving unit 180 may adjust the position of at least one of the partial reflective film 120 and the supporting part 131 such that the partial reflective film 120 and the supporting part 131 are positioned parallel to each other. In the embodiment of the present invention, the surface shape inspection apparatus is for accurately checking the surface shape of the object to be inspected 130 using the path difference between the partial reflection film 120 and the light reflected from the object to be inspected 130, Adjusts the posture such that the partial reflection film 120 and the support portion 131 are positioned in parallel.

In another embodiment of the present invention, when the object to be inspected 130 is composed of a plurality of layers, the third light not reflected from the surface of the object to be inspected 130 among the light not reflected by the partial reflection film 120 is inspected May be reflected at the surface of at least one of the layers beneath the surface of the object (130). For example, in the case of a device composed of a plurality of layers such as a PCB, a semiconductor chip, an LCD, an LED, a solar cell, etc., it is necessary to inspect the surface of the plurality of layers. To this end, the sensing unit 140 receives the third light reflected from the surface below the upper surface without being reflected from the upper surface of the object to be inspected 130, and the interference between the first light and the third light The shape information can be obtained with respect to the inner surface of the object 130 to be inspected. In this case, in order for the sensing unit 140 to acquire shape information about the inner surface of the object to be inspected, the path difference between the first light and the third light must be smaller than the coherence length of the light. The position of at least one of the partial reflection film 120 and the support part 131 is adjusted so that the distance between the partial reflection film 120 and the inner surface on which the third light is reflected is smaller than the interference distance of the light, .

In the embodiments of the present invention, when the area recognized by the sensing unit 140 is smaller than the size of the inspected object 130 or the shape recognized by the sensing object 140 is different from the shape of the inspected object 130, The driving unit 180 or the other driving unit (not shown) may be mounted on the supporting unit 131 or the light source unit 100, the optical distributor 110, the partial reflective film 120, The position of the sensing unit 140 can be adjusted. For example, after the sensing unit 140 first obtains the surface shape information of the object to be inspected 130 using the interference signal between the first light and the second light, the position of the object can be adjusted. Alternatively, the driving means separately provided may be configured to detect the surface shape of the remaining area of the inspection object 130 that the driving unit 180 does not sense by the sensing unit 140, The position of the light source unit 100, the light distribution unit 110, the partial reflection film 120, and the sensing unit 140 can be adjusted.

As described above, the surface shape inspection apparatus according to the embodiments of the present invention can be used not only in a method of emitting light for generating an interference signal in the light source unit 100, but also in a method of detecting the light emitted from the light source unit 100 using the partial reflection film 120 It is possible to stably obtain the optical interference signal by controlling the distance difference between the partial reflection film 120 and the object to be inspected 130 to be less than the optical interference distance, The surface shape of the object 130 can be efficiently secured.

The surface shape inspection apparatus according to the embodiments of the present invention further includes a first optical system 150 positioned between the light source unit 100 and the optical distributor 110. The first optical system 150 spatially expands the light emitted from the light source unit 100 in the shape of a line or a surface corresponding to the size of the object to be inspected 130.

The surface shape inspection apparatus of the present invention further includes a second optical system 160 positioned between the optical distributor 110 and the partial reflective film 120. The second optical system 160 spatially expands the light passing through the optical distributor 110 in the shape of a line or a surface corresponding to the size of the object to be inspected 130.

Furthermore, the surface shape inspection apparatus of the present invention further includes a third optical system 170 positioned between the optical distributor 110 and the sensing unit 140. The third optical system 170 spatially expands the light reflected from the partial reflection film 120 and the inspection object 130 and passed through the optical distributor 110 in the form of a line or a surface.

To this end, the first optical system 150, the second optical system 160, and the third optical system 170 have a lens (not shown) for extending a single path of light in the form of a line or a plane. The magnification of the lenses provided in the first optical system 150, the second optical system 160, and the third optical system 170 can be adjusted corresponding to the size of the object 130 to be inspected. For example, when the size of the object to be inspected 130 varies, the magnification of the lens can be adjusted corresponding to the size change of the object to be inspected 130.

In the embodiments of the present invention, the surface shape inspection apparatus includes a first optical system 150, a second optical system 160, and a third optical system 170, A collimator (not shown).

Accordingly, the first optical system 150, the second optical system 160, and the third optical system 170 expand and propagate the transmitted light corresponding to the size of the object to be inspected 130, The surface shape can be obtained efficiently.

FIG. 2 is a view for explaining an interference phenomenon due to a light path difference by reflecting light on the surface of the partial reflection film and the inspection object shown in FIG. 1, respectively.

2, in the embodiments of the present invention, the light emitted from the light source part is incident on the partial reflection film 200, the surface 202 of the object to be inspected, the substrate surface 204 of the object to be inspected, 206, respectively. In this case, in order to generate an interference signal between traveling light beams, the path difference between the light beams must be smaller than the optical interference distance. In other words, the time difference due to the path difference between the traveling lights must be shorter than the optical interference time.

Specifically, when the light advances to path 1, the light passes through the first light 210 reflected from the partial reflection film 200, the second light 212 reflected from the substrate surface 204 of the object to be inspected, And the third light 214 reflected by the inner substrate surface 206.

In this case, in order to acquire the surface shape information of the object to be inspected using the interference signal of light in the sensing unit, interference must occur between the received light. In order to obtain the shape of the substrate surface 204 of the object to be inspected, interference must occur between the first light 210 and the second light 212. In order to obtain the shape of the inner substrate surface 206 of the object to be inspected Interference should occur between the first light 210 and the third light 214. The path difference between the first light 210 and the second light 212 and the path difference between the first light 210 and the third light 214 should be smaller than the interference distance 240 of the light.

When proceeding to the path (2), the light passes through the fourth light 220 reflected from the partial reflection film 200, the fifth light 222 reflected from the surface 202 of the object to be inspected, And the sixth light 224 reflected by the first and second light sources 206 and 206.

Similarly, in order to obtain the shape of the surface 202 of the object to be inspected in the sensing unit, interference must occur between the fourth light 220 and the fifth light 222, and the shape of the inner substrate surface 206 of the object to be inspected Interference will have to occur between the fourth light 220 and the sixth light 224 in order to acquire. The path difference between the fourth light 220 and the fifth light 222 and the path difference between the fourth light 220 and the sixth light 224 should be smaller than the coherence distance 240 of the light.

Here, the path difference between the first light 210 and the second light 212 in the case of proceeding to the path (1) is a path difference between the fourth light 220 and the fifth light 222 And has a relatively long path difference. Accordingly, an interference signal generated between the first light 210 and the second light 212 having a relatively long path difference and the fourth light 220 and the fifth light 222 having a relatively short path difference The generated interference signals have different waveforms. Accordingly, the sensing unit can grasp the shape of the object to be inspected through interference signals of different waveforms.

The path difference between the first light 210 and the third light 214 in the case of proceeding to the path 1 is the path difference between the fourth light 220 and the sixth light 224 And has a relatively long path difference. The interference between the fourth light 220 and the sixth light 224 having a relatively short path difference and an interference signal generated between the first light 210 and the third light 214 having a relatively long path difference Through the difference of the generated interference signals, the sensing unit can acquire shape information about the inner substrate surface of the inspection object.

As described above, an interference signal is generated between lights having different paths by the distance between the partial reflection film and the object to be inspected, and the sensing unit acquires the shape information of the surface, the substrate surface, and the inner substrate surface of the object to be inspected through the interference signal You can.

Although not shown, when the interference distance of the light changes, the distance between the partial reflection film and the object to be inspected may be adjusted to be smaller than the interference distance of the light corresponding to the changed interference distance of the light.

FIG. 3 is a view for explaining an example of adjusting the positions of the partial reflection film and the supporting portion shown in FIG. 1. FIG.

Referring to FIG. 3, the support according to another embodiment of the present invention includes a first support 302 and a second support 303 for supporting the inspection object 301.

The first support base 302 supports the lower portion of the inspection object 301 by placing the inspection object 301 thereon.

The second support base 303 is positioned at the edge of the first support base 302 and extends in the direction of the partial reflection film 300. The second support base 303 has a columnar shape and is formed higher than the height of the object 301 to be inspected.

At this time, optical interference occurs between the light (reference signal) reflected by the partial reflection film, the light (external sample signal) reflected from the upper surface of the object to be inspected, and the light (internal sample signal) reflected from the lower surface of the object to be inspected, In order for the sensing unit to receive the optical interference signal, the path difference between the lights must be smaller than the interference distance of the light.

The position of at least one of the partial reflective film 300 and the supporting portions 302 and 303 can be adjusted so that the driving portion (not shown) contacts the upper surface of the second supporting table 303, have.

When the partial reflection film 300 and the second support base 303 are controlled to be in contact with each other within a range smaller than the optical interference distance, the partial reflection film 300 and the supports 302 and 303 are integrated in a vibration- So that more accurate inspection of the object to be inspected can be performed by minimizing the influence of the generation of optical interference signals and vibration and noise.

Although not shown, a support is provided at the edge of the surface of the object to be inspected, and a partial reflection film is brought into contact with the upper surface of the support, thereby vibrating it integrally to minimize the influence of the generation of optical interference signals and vibration and noise A more accurate inspection of the object to be inspected may be performed.

4 is a view for explaining an interference signal and a corresponding spectrum signal received by the sensing unit shown in FIG.

Referring to FIG. 4, the sensing unit according to embodiments of the present invention includes a first light reflected by the partial reflection film, a surface of the object, a substrate surface, and a plurality of second light beams reflected from the inner reflection surface, The surface of the object to be inspected, the substrate surface, and the internal reflection surface shape are acquired through the interference signal. At this time, the sensing unit senses each pixel corresponding to each position of the surface of the object to be inspected.

In the embodiments of the present invention, the sensing unit receives a different interference signal due to a difference in the path of received light according to the height of the surface of the object to be inspected. In addition, the sensing unit may receive different interference signals due to differences in the path difference of the received light depending on the surface of the inspection object on which the structure is formed and the surface of the inspection object on which the structure is not formed.

As shown in FIG. 4, the optical interference signal having a relatively short optical path difference exhibits a long optical intensity cycle for each wavelength, and the optical interference signal having a relatively long optical path difference has a short optical intensity intensity for each wavelength.

Therefore, the sensing unit can grasp the optical path difference of the light received through the optical interference signal, and thereby can grasp the surface shape of the object to be inspected.

Meanwhile, the sensing unit obtains a new light intensity at each pixel at a time interval of at least half or less than one period of the light intensity of the interference signal having the light intensity change. On the other hand, the frame rate of the sensing unit refers to a speed at which the image is received while repeating an operation of turning off and on at a constant speed (frame / sec). Therefore, according to Nyquist theory, it is possible to measure the light intensity without forgetting the cycle value by repeatedly turning off and on the light for a time shorter than twice as large as the light intensity. For example, an optical signal with a frequency of 1000 Hz will flicker every 0.001 second. If the detector blinks once for 0.01 second, it will not be able to grasp the period of the optical signal at all. Therefore, use a detector that flickers at a time interval of at least 0.0005 seconds. It is necessary to grasp the frequency of the optical signal.

In addition, the sensing unit Fourier transforms the optical interference signal having a periodic light intensity change by scanning the central wavelength to acquire a spectrum signal corresponding to the period value.

In this case, the spectral signal of the optical interference signal having a longer optical intensity per wavelength has a peak on the lower frequency, and the spectrum signal of the optical interference signal having a shorter optical intensity per wavelength has a peak on the higher frequency, It is possible to correspond the optical path difference from the frequency of the optical interference signal.

For example, when the sensing unit receives an optical interference signal from two light beams reflected from the flat surface of the partial reflection film and from two light beams reflected from the surface of the object to be inspected having different heights, Since the signal of the path difference becomes a long periodic optical interference signal, it can appear as a spectrum signal having a peak on a low frequency. Similarly, since the signal of the long optical path difference corresponding to the low surface shape becomes a short periodic optical interference signal, the sensing unit appears as a spectrum signal having a peak on the high frequency.

In the embodiments of the present invention, the sensing unit successively acquires the interference signal at each pixel for at least one period of time required for scanning for a plurality of wavelengths of the light. For example, to know the center frequency of a spectrum signal, each pixel of the sensing unit (camera) continuously obtains a repetitive light intensity signal that increases and decreases in light intensity during a scan of a plurality of wavelength numbers do. In this case, if the area recognized by the sensing unit does not cover the entire area of the object to be inspected, before each of the pixels of the sensing unit is moved to a position corresponding to another area of the object to be inspected, As shown in Fig.

Therefore, the sensing unit can grasp the optical path difference through the spectrum signal, and thereby obtain the surface shape information of the object to be inspected.

5A and 5B are images and photographs for explaining the result of acquiring the surface shape information according to the embodiments of the present invention. 5A and 5B illustrate an image obtained by stacking a slide glass and an image of the object using the surface shape inspection apparatus according to an embodiment of the present invention.

Referring to FIG. 5A, the object to be inspected is formed by stacking a second glass 502 and a third glass 503 at a predetermined interval on a first glass 501 having a predetermined thickness. The second glass 502 and the third glass 503 are provided in the first glass 501 at a predetermined distance from each other. At this time, the second glass 502 and the third glass 503 are formed to be thinner than the first glass 501.

In the embodiments of the present invention, the second glass 502 and the third glass 503 are not limited to being formed in such a manner that different objects are spaced apart from each other, but the second glass 502 and the third glass 503 ) Is a single glass and may be assumed to be cracked.

Referring to FIG. 5B, according to a result of obtaining a surface shape of the object to be inspected by irradiating a light beam to a predetermined region using a surface shape inspection apparatus according to embodiments of the present invention, The resulting image is shown as a photograph.

Specifically, the first glass 501 is positioned at a lower thickness than the second glass 502 and the third glass 503, and the second glass 502 and the third glass 503 It can be confirmed that they are stacked on the first glass 501 at regular intervals. It can also be seen that the second glass 502 and the third glass 503 are spaced apart from each other by an interval of a degree of the cracks, and the thickness of the second glass 502 and the third glass 503 is It is also possible to confirm that it is thinner than the thickness of the glass 501.

As described above, the surface shape inspection apparatus according to the embodiments of the present invention can acquire information about the surface shape of an assumed image as the same image, and even when the object to be inspected is composed of a plurality of layers, It can be confirmed that all the information on the surface shape can be obtained.

The embodiments described above are illustrative of the structure and function of the basic surface shape inspection apparatus for the sake of concrete explanation, but are not limited thereto. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

100: light source part 110: light distribution part
120: partial reflection film 130: object to be inspected
131: Support part 140:

Claims (23)

An inspection apparatus for inspecting a surface shape of an object to be inspected,
A light source unit that sequentially scans a plurality of wavelengths and emits light whose wavelength tuning is repeated;
A partial reflection film for reflecting the first light, which is a part of the light emitted from the light source unit;
A support for supporting the object to be inspected so that a second light among the light emitted from the light source is not reflected by the partial reflection film;
Wherein a distance between the partial reflection film and the support part is set to be smaller than a coherence length of the optical path so that interference can be generated by a path difference between the first light and the second light, A driving part for adjusting a position of at least one of the partial reflection film and the supporting part so that the partial reflection film and the supporting part are positioned; And
And a sensing unit for receiving the first light and the second light for generating an interference signal and acquiring information about the surface shape of the object to be inspected through the interference signal,
The support portion includes a first support for supporting the lower portion of the inspected object by placing the inspected object and a columnar second support located at an edge of the first support and higher than a height of the inspected object, Wherein the driving unit adjusts the position of at least one of the partial reflection film and the supporting unit such that the lower surface edge of the partial reflection film is in contact with the upper surface of the second support base. An inspection apparatus for inspecting a surface shape of an object to be inspected,
A light source unit that sequentially scans a plurality of wavelengths and emits light whose wavelength tuning is repeated;
A partial reflection film for reflecting the first light, which is a part of the light emitted from the light source unit;
A support for supporting the object to be inspected so that a second light among the light emitted from the light source is not reflected by the partial reflection film;
At least one of the partial reflection film and the supporting part is formed so that a distance between the partial reflection film and the supporting part is smaller than a coherence length of the optical part so that interference can be caused by a difference in path between the first light and the second light. A driving unit for adjusting a position of the driving unit; And
And a sensing unit for receiving the first light and the second light for generating an interference signal and acquiring information about the surface shape of the object to be inspected through the interference signal,
The support portion includes a first support for supporting the lower portion of the inspected object by placing the inspected object and a columnar second support located at an edge of the first support and higher than a height of the inspected object, Wherein the driving unit adjusts the position of at least one of the partial reflection film and the supporting unit such that the lower surface edge of the partial reflection film is in contact with the upper surface of the second support base. 3. The method according to claim 1 or 2,
And an optical distributor for transmitting the light from the light source in a direction in which the inspection object is located. The method of claim 3,
The optical distributor passes the first light reflected from the partial reflection film and the second light reflected from the inspected object in a direction in which the sensing unit is positioned and the first light and the second light are combined on the axis of the sensing unit And the surface shape inspection device. 3. The method according to claim 1 or 2,
Wherein the surface of the partial reflection film is coated with a material capable of adjusting the reflectance and the reflection position of the light. 6. The method of claim 5,
Wherein the surface of the partial reflection film facing the inspection object is coated with a material for suppressing reflection of light. 3. The method according to claim 1 or 2,
The driving unit
A first driver for controlling a position of the partial reflection film; And
And a second driving unit for controlling the position of the support unit. 3. The method according to claim 1 or 2,
The distance between the partial reflection film and the supporting part is smaller than the coherence length of the light so that the difference between the first required time for the first light to proceed and the second required time for the second light to proceed, Is smaller than the coherence time of the light. 3. The method according to claim 1 or 2,
When the sensing unit primarily recognizes the area smaller than the size of the inspected object, after the sensing unit acquires the surface shape information of the inspected object using the interference signal, And the position of the support is adjusted to sense the surface shape of the remaining area. 3. The method according to claim 1 or 2,
Wherein when the sensing unit primarily recognizes the area smaller than the size of the inspected object, the sensing unit first obtains the surface shape information of the inspected object using the interference signal, Wherein the position of at least one of the light source unit, the partial reflection film, and the sensing unit is adjusted while the position of the inspection object is fixed in order to sense the surface shape of the remaining area of the object. The method of claim 3,
Further comprising a first optical system located between the light source unit and the optical distributor and for expanding the light emitted from the light source unit in a line shape or a surface shape corresponding to the size of the inspection object, Inspection device. The method of claim 3,
And a second optical system located between the optical distributor and the partial reflection film for spatially expanding the light from the optical distributor in the form of a line or a surface corresponding to the size of the object to be inspected. The surface shape inspection apparatus comprising: The method of claim 3,
And a third optical system positioned between the optical distributor and the sensing unit and for expanding the light reflected from the partial reflection film and the object to be inspected and passing through the optical distributor in the form of a line or a space. Of the surface shape inspection device. The method of claim 3,
A first optical system located between the light source unit and the optical distributor for expanding the light emitted from the light source unit in the form of a line or a shape corresponding to the size of the inspected object, A second optical system positioned between the optical distributor and the sensing unit for spatially expanding the light from the optical distributor in the form of a line or a surface corresponding to the size of the inspected object; And a third optical system for reflecting the light reflected from the object and spatially expanding the light passing through the light distribution unit in the form of a line or a surface,
Wherein the first optical system, the second optical system, and the third optical system have a lens for extending a single path of light in the form of a line or a surface, and the magnification of the lens corresponds to the size of the inspected object. Shape checking device. 15. The method of claim 14,
Wherein the magnification of the lens is adjusted according to a change in size of the inspection object when the size of the inspection object changes. 15. The method of claim 14,
Further comprising a collimator for advancing the path of the expanded light by the lens in parallel. delete delete delete 3. The method according to claim 1 or 2,
Wherein the sensing unit senses the surface shape of the inspection object for each pixel corresponding to each position on the surface of the inspection object through the interference signal generated by the path difference between the first light and the second light. Shape checking device. 3. The method according to claim 1 or 2,
Wherein the sensing unit performs a Fourier transform on the interference signal having a periodic light intensity change by scanning the center wavelength to obtain a spectrum signal corresponding to the period value. 3. The method according to claim 1 or 2,
Wherein the sensing unit continuously acquires the interference signal at each pixel for at least one period of time required for scanning the light with a plurality of wavelengths. 3. The method according to claim 1 or 2,
Wherein the sensing unit acquires a new light intensity at each pixel at intervals of at least half of a period of the light intensity of the interference signal having the change of the light intensity.

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