TW201520510A - Apparatus for measuring thickness and method for measuring thickness for the same - Google Patents

Abstract

The present invention relates to an apparatus for measuring a thickness, which is an apparatus for measuring a thickness using a reflectometer, comprising: a light source for emitting light; a light filter unit for receiving the light emitted from the light source, selectively transmitting the light having a plurality of different frequencies so as to be modulated to the light having an intensity distribution, wherein a wavelength width of the light having the intensity distribution is adjusted; an optic system for irradiating an object being measured with the light modulated from the light filter unit, and receiving the light reflected from the object being measured; a light detection unit for receiving the light passing through the optic system so as to acquire reflection information; and a control unit for setting a plurality of frequencies capable of transmitting through the light filter unit so as to adjust the wavelength width of the light modulated by the light filter unit, and measuring the thickness of the target being measured by comparing pre-stored theoretical reflection information modelled by a mathematical formula, with reflection information acquired through the light detection unit.

Description

Thickness measuring device and measuring method thereof

The present invention relates to a thickness measuring device and a thickness measuring method using the same, and more particularly to a measuring device capable of improving thickness measuring accuracy regardless of a material or a measuring position of a measuring object, and a thickness measuring method using the same.

The transparent film widely used in the field of LCD and semiconductor has a great influence on the subsequent manufacturing process because its thickness distribution has a great influence on the subsequent manufacturing process. Therefore, a monitoring system capable of monitoring the thickness of the transparent film has appeared.

In general, the thickness of a film can be measured by a mechanical method and an optical method using a stylus, and among optical methods, an instrument such as an interferometer and a reflectometer is widely used for the amount. Measurement.

Referring to the first drawing, a schematic diagram of a thickness measuring device using a Reflectometry is shown; as shown in the first figure, among the conventional thickness measuring device 1 using a reflectance photometer, light irradiated from the light source 10 After passing through the respective lenses (21, 22), passing through the beam splitter 30 The object is incident on the measurement object, and is again collected by the objective lens 31. Then, the light reflected through the transparent film S' passes through the beam splitter 30 and the objective lens 32 is incident into the spectrometer 40 or the camera 50; and, the spectrometer 40 is used to acquire the reflectance of the light reflected from the detection object with respect to the wavelength. The varying reflectance profile is displayed and displayed.

Here, in order to determine the thickness of the transparent film S', a method of comparing the reflectance distribution curve measured by the transmission spectrometer 40 with the reflectance distribution curve by the mathematical simulation is applied (refer to the document: Korean Patent Laid-Open No. 10- 2013-0021425).

First, it is assumed that there are a plurality of transparent films S' having different thicknesses from each other, and an individual reflectance profile is generated for each of the transparent films S' by a mathematical formula. Thereafter, a modeled reflectance profile that most closely matches the measured reflectance profile is employed in the plurality of reflectance profiles that are modeled, and a thickness corresponding to the modeled reflectance profile It can be determined as the thickness of the film layer.

However, in the conventional thickness measuring device, although it is easier to generate the measured reflectance curve for the center portion of the measuring object, the reflectance value of the reflectance distribution curve will be smaller as the edge side of the measuring object is measured. As such, there will be problems in that it is difficult to compare with the modeled reflectance profile or cannot be compared.

In addition, depending on the characteristics of the material of the measurement object, the reflectance value of the reflectance distribution curve measured from the measurement object is too high, which will cause difficulty The modeled reflectance profile is compared or cannot be compared.

According to the above, it can be known that there is a problem that the thickness measurement accuracy is lowered depending on factors such as the material of the measurement object or the measurement position.

Accordingly, the present invention has been made to solve the above-described conventional problems, and an object thereof is to provide a thickness measuring device and a thickness measuring method using the same, the thickness measuring device and a thickness measuring method using the same can be measured with a measuring object The material or measurement position increases the thickness measurement accuracy independently.

The object is achieved by a thickness measuring device according to the invention, the thickness measuring device using a Reflectometer, comprising: a light source for emitting light; and a filter portion for receiving the light source Light rays are selectively modulated by the plurality of frequencies different from each other to be modulated into light having an intensity distribution, and the wavelength width of the light having the intensity distribution can be adjusted; the optical system is directed to the measuring object side Irradiating light modulated by the filter portion, and light reflected from the measuring object side is incident into the optical system; and a light detecting portion that receives light passing through the optical system to obtain reflectance information; a control unit that sets a plurality of frequencies transmittable to the filter portion to adjust a wavelength width of light modulated by the filter, and is modeled and transmitted by a mathematical expression The saved theoretical reflectance information is compared with the reflectance information obtained by the light detecting portion to measure the thickness of the measuring object.

Here, it is preferable that the filter portion is a plurality of Acousto-Optical Tunable Filters arranged to be spaced apart from each other in the direction in which light emitted from the light source is performed.

Here, the filter portion preferably combines the light while maintaining a wavelength of light that transmits the plurality of frequencies that have been set, respectively, thereby modulating light transmitted from the filter portion to have intensity Distributed light.

Here, the optical system preferably includes: a first beam splitter for reflecting light modulated by the filter portion or transmitting light reflected from the measuring object; and a lens portion disposed at the Between a spectroscope and a measuring object, for condensing light reflected from the first beam splitter toward a measuring object side, the thickness measuring device further comprising: a camera portion for receiving from the optical system The light reflected by the object is measured to obtain image information of the measurement object.

Here, the control unit preferably includes: a frequency setting module configured to set a plurality of frequencies transmittable to the filter portion; and a saving module configured to save and be modeled by each of the thicknesses Corresponding plurality of theoretical reflectance information; and a comparison judging module comparing the reflectance information measured by the photodetecting portion with the theoretical reflectance information held in the save module to determine the thickness of the measuring object .

Here, the control unit preferably further includes: a conversion module, Converting at least one of reflectance information measured by the light detecting unit and theoretical reflectance information stored in the save module to a frequency adjusted by the frequency setting module, the comparison judgment The module measures the thickness of the measurement object by using at least one of the reflectivity information and the theoretical reflectance information that has been converted.

Further, the object is achieved by the thickness measuring method of the present invention, characterized in that it comprises a modulating step of setting a plurality of frequencies transmissive for a filter portion for modulating light emitted from a light source, Adjusting the wavelength width of the intensity distribution of the light modulated by the filter portion; the step of setting the theoretical reflectance information, setting the theoretical reflectance information corresponding to each thickness through a mathematical formula; the step of acquiring the reflectance information, The measuring object side illuminates the light modulated by the filter portion to obtain the reflectance information of the measuring object; the matching step compares the theoretical reflectance information with the reflectance information to The theoretical reflectance information most similar to the reflectance information is selected in the reflectance information; and the thickness determining step determines the thickness corresponding to the theoretical reflectance information selected in the matching step as the thickness of the measurement object.

Here, the step of setting the theoretical reflectance information preferably includes a converting step of considering the theoretical reflectance information set by the theoretical reflectance setting step in consideration of a plurality of frequencies set by the modulating step. Conversion.

Here, it is preferred that when the matching step is not possible to select and the opposite The modulation step is re-executed when the radiance information is most similar to the theoretical reflectance information.

According to the present invention, there is provided a thickness measuring device and a thickness measuring method using the same, which thickness measuring device and thickness measuring method using the same can easily adjust the wavelength width of light having an intensity distribution incident on the measuring object side.

In addition, an accurate thickness measurement can be performed on the edge region of the measurement object having a small reflectance value of the reflectance distribution curve.

Further, even if the measurement object is formed of a material that forms a reflectance value of an excessively high reflectance profile, accurate thickness measurement can be performed.

<present invention>

S‧‧‧Measurement object

100‧‧‧ thickness measuring device

110‧‧‧Light source

120‧‧‧Filter Department

121‧‧‧Lightwave Generation Department

121a‧‧‧First Lightwave Generation Department

121b‧‧‧Second light wave generation department

121c‧‧‧ Third Lightwave Generation Department

130‧‧‧Optical system

131‧‧‧ spectroscopy

132‧‧‧Lens Department

133‧‧‧Semi-transmission mirror

132b‧‧‧second lens section

140‧‧‧Light Inspection Department

150‧‧‧ camera department

160‧‧‧Control Department

161‧‧‧frequency setting module

162‧‧‧Save module

163‧‧‧Transition module

164‧‧‧Comparative judgment module

S100‧‧‧ thickness measurement method

S110‧‧‧Modulation step

S120‧‧‧Setting steps for theoretical reflectance information

S124‧‧‧Molding steps

S125‧‧‧ conversion steps

S130‧‧‧Steps for obtaining reflectance information

S140‧‧‧ Matching steps

S150‧‧‧ thickness determination step

<Prior technology>

S’‧‧·transparent film

1‧‧‧ thickness measuring device

10‧‧‧Light source

21‧‧‧ lens

22‧‧‧ lens

30‧‧‧Distributor

31‧‧‧ Objective lens

32‧‧‧ Objective lens

40‧‧‧ Spectrometer

50‧‧‧ camera

The first figure is a schematic diagram of a thickness measuring device using a reflection photometer; the second drawing is a conceptual diagram of the thickness measuring device of the present invention; and the third A to the third B are schematic views of the operation of the optical filter portion of the present invention; The fourth drawing is a schematic diagram of the structure of the control portion of the present invention; the fifth drawing is a flow chart of the thickness measuring method of the present invention; the sixth and second B drawings are the thickness measuring methods of the fifth figure before and after the wavelength modulation step a light intensity chart; the seventh figure is a reflectance information chart obtained based on light before and after the modulation step in the thickness measurement method of the fifth figure; The eighth to eighth C diagrams are diagrams of the conversion steps in the thickness measurement method shown in the fifth diagram.

In order to more clearly describe a thickness measuring device and a measuring method thereof according to the present invention, a preferred embodiment of the present invention will be described in detail below with reference to the drawings.

Referring to the second figure, a conceptual diagram of the thickness measuring device of the present invention; as shown in the second figure, the thickness measuring device 100 in the embodiment of the present invention modulates light into light before it is incident on the measuring object S. The light having the intensity distribution and adjusting the wavelength width of the light having the intensity distribution, so that the reflectance information measured after the reflection from the measuring object S can be improved, and the thickness measuring device 100 of the present invention includes the light source 110 and the filter The unit 120, the optical system 130, the light detecting unit 140, the camera unit 150, and the control unit 160.

The light source 110 is used to emit light, and is set to emit white light in the embodiment, but is not limited thereto. In addition, in the embodiment, the light source 110 is a halogen lamp, but is not limited thereto, and a plurality of source light sources can be used.

Please refer to the third A diagram and the third B diagram at the same time, which is a schematic diagram of the operation of the optical filter portion of the present invention. In the third A diagram, the filter portion provided with three light wave generating portions having different frequencies is schematically shown. And in the third B picture The filter portion provided with five light wave generating portions having different frequencies is schematically shown.

As shown in the third A diagram and the third B diagram, the filter portion 120 receives the light emitted from the light source 110 and selectively transmits the plurality of frequencies with respect to the set frequency, thereby modulating the light to have intensity. The light is distributed and the wavelength width of the light having the intensity distribution is adjusted. In addition, here, in order to facilitate the further description, the filter unit 120 shown in FIG.

In the present embodiment, the filter unit 120 transmits the light wave generating unit 121 that emits light of a specific frequency in a direction intersecting the direction in which the light beams, and modulates the light into light having a fine wavelength width. Here, a plurality of light wave generating portions 121 are arranged along the direction in which light is emitted, and each of the light wave generating portions 121 is provided to generate light waves of different frequencies.

Further, in the present embodiment, the light wave generating unit 121 is provided with a first light wave generating unit 121a, a second light wave generating unit 121b, and a first light wave generating unit having light waves having frequencies of 120 MHz, 130 MHz, and 140 MHz, respectively. The three-light generating unit 121c is not limited thereto, and the frequency difference between the respective light wave generating units 121 may be increased or decreased in order to increase or decrease the wavelength width of the modulated light.

Further, the light emitted from the light source 110 is modulated by the respective light wave generating portions 121a, 121b, and 121c to have light having a specific frequency and having a fine wavelength width; here, the light is transmitted through the light wave generating portions 121a and 121b, 121c is combined in a state in which each specific frequency is saved, and is modulated into light having an intensity distribution.

Again, the light intensity distribution is obtained by combining the light passing through the respective light wave generating portions 121a, 121b, and 121c. However, the light is not continuously connected within the range of the intensity distribution, but only the light having the specific frequency is broken. Continuous connection; that is, when modulating light, it has an intensity distribution and can prevent noise.

Further, it is preferable to adjust the intensity of the light through the respective light wave generating portions 121a, 121b, 121c so that the light ray permeable to the filter 120 has a desired intensity distribution by the user.

In other words, in the present embodiment, the light modulated by the second light wave generating unit 121b is controlled to have the strongest intensity, and the light modulated by the first light wave generating unit 121a and the third light wave generating unit 121c is controlled to be Has almost the same strength.

Further, in the embodiment, the filter portion 120 is provided by a plurality of Acousto-Optical Tunable Filters which are spaced apart from each other in the direction in which the light rays are conducted, but the present invention is not limited thereto.

The optical system 130 is configured to receive light modulated by the filter portion 120 and to inject it toward the measurement object S side, and the light reflected from the measurement object S is incident on the optical system 130. The optical system 130 includes a beam splitter 131, a lens portion 132, and a semi-transmission Mirror 133.

The spectroscope 131 is configured to receive the light modulated by the filter 120 and reflect the light toward the measurement object S side or transmit the light reflected from the measurement object S. Further, the lens portion 132 is for collecting the light reflected from the spectroscope 131 toward the measurement target S side, and may be provided by the objective lens, but is not limited thereto.

The semi-transmissive mirror 133 is for reflecting or transmitting a part of the light reflected from the measuring object S, thereby guiding the direction to the light detecting portion 140 side or the camera portion 150 side which will be described later. Further, the second lens portion 132b for condensing the light reflected from the measurement object may be provided between the spectroscope 131 and the semi-transmissive mirror 133, but is not limited thereto. Further, the structure of the optical system 130 is a well-known structure, and thus is not limited to the structure described, and of course, the optical system 130 including or omitting other structures may be employed.

The light detecting unit 140 is configured to receive light reflected from the measuring object S and passing through the optical system 130, and perform spectral analysis to obtain reflectance information. Further, in the present embodiment, the so-called reflectance information means a reflectance profile indicating a change in reflectance with respect to the intensity of light and the wavelength, but is not limited thereto.

In addition to this, the camera section 150 is for receiving light reflected from the measuring object S and passing through the optical system 130, and imaging the reflectance information as an image. In the present embodiment, the camera unit 150 can utilize a CCD camera having a suitable number of pixels for the area to be measured. (Chargecoulpeddevice), but not limited to this.

Please refer to the fourth figure, which is a schematic diagram of the structure of the control unit of the present invention; as shown in the fourth figure, the control unit 160 is configured to set a plurality of frequencies of the transmissive filter unit 120 and adjust the transmissive filter unit 120. And the wavelength width of the modulated light, and the theoretical reflectance information that is modeled and saved by the mathematical expression is compared with the reflectance information obtained by the transmitted light detecting portion 140 to measure the thickness of the measuring object S, including the frequency setting. The module 161, the save module 162, the conversion module 163, and the comparison determination module 164.

The frequency setting module 161 is configured to set a plurality of frequencies of the transmissive filter unit 120. According to the embodiment, the frequency setting module 161 is configured to set a specific frequency of the light wave emitted from each of the light wave generating units 121. .

Here, the wavelength of the intensity distribution of the light modulated by the filter unit 120 can be changed by controlling the difference between the specific frequencies of the light waves emitted from the respective light wave generating units 121 or the number of generated light waves. width.

Further, when the wavelength width of the intensity distribution of the light modulated by the filter unit 120 is changed, the reflectance value of the reflectance information obtained from the light detecting portion 140 thereafter is changed, and the control frequency setting module is transmitted through 161 causes the reflectance value of the reflectance information to have a value that is most suitable for comparison with theoretical reflectance information.

The save module 162 is configured to save a plurality of theoretical reflectance information corresponding to each thickness through a mathematical expression. Here, the mathematical formula for modeling the theoretical reflectance information is as follows:

Here, R ^ρ (d, λ ) is the total reflection coefficient of the P wave parallel to the incident surface, and r ^ρ ₁₂ is the Fresnel reflection coefficient of the P wave of the air layer and the side interface of the measurement object, r ^ρ ₂₃ is the Fresnel reflection coefficient of the P wave on the side interface of the support object and the support layer supporting the measurement object, and β is the phase shift amount generated when the light passes through the measurement object.

Here, R ^δ (d, λ ) is the total reflection coefficient of the S wave perpendicular to the incident surface, and r ^δ ₁₂ is the Fresnel reflection coefficient of the S wave of the air layer 12 and the side interface of the measurement object, r ^δ ₂₃ is the Fresnel reflection coefficient of the S wave on the side interface of the measurement object and the support layer.

Here, d is the thickness of the measurement object, To measure the complex refractive index of the object, φ ₂ is the angle of refraction on the object to be measured.

Here, R ₁ is the theoretical reflectance generated by mathematical modeling, I _i is the intensity of the incident light, and _Ir is the intensity of the reflected light.

Among them, the theoretical reflectance for a predetermined thickness can be obtained by substituting Mathematical Formula 1 to Mathematical Formula 3 into Mathematical Formula 4, and the theoretical reflectance distribution curve can be generated by changing the wavelength and expressing the reflectance distribution as a graph.

Further, the theoretical integrated reflectance distribution curve can be obtained by multiplying the theoretical reflectance distribution curve generated by the mathematical expression 4 by the intensity distribution of the light reflected from the measuring object, which is calculated by the following mathematical formula:

Here, R ₂ is a theoretical integrated reflectance generated by mathematical modeling, λ ^* is a specific wavelength, I _i is an input intensity, _Ir is an output intensity, and I ₀ is a maximum value of intensity at a specific wavelength, I ₀ F _λ is the intensity distribution curve of a specific wavelength, and R ₁ is a theoretical reflectance distribution curve.

That is, after the save module 162 obtains the reflectance distribution curve corresponding to each thickness, the integrated reflectance curve corresponding to each thickness is obtained through the reflectance distribution curve and saved.

In addition, when the intensity distribution of the light is changed by the transmission frequency setting module 161, the storage module 162 can regain the theoretical reflectance information and save it by using the changed intensity distribution value, but it is not limited thereto. The conversion module 163, which will be described later, converts the saved theoretical reflection Information.

The conversion module 163 is configured to change any one of the reflectance information measured by the light detecting unit 140 or the theoretical reflectance information stored in the save module 162 when the frequency adjustment module 161 performs frequency adjustment.

As described above, when the theoretical reflectance information is obtained by mathematical modeling, the intensity of the incident light is assumed to be the initial set value and calculated.

Here, when the intensity distribution of the light is changed by the transmission frequency setting module 161, the intensity of the incident light also changes, so that the reflectance information and the theoretical reflectance information may not be compared under the same conditions. The problem is therefore necessary to change any of the two conditions described so that these conditions are consistent.

In the present embodiment, a method of converting the theoretical reflectance information that has been saved in the save module 162 is employed, and the converted integral reflectance distribution curve is determined by the following mathematical formula:

Here, F _λ **( λ ) represents the amount of change in the intensity of light with respect to the initial set value, and other mathematical expressions are the same as those described above.

In addition, as shown in the embodiment of the present invention, a method of converting theoretical reflectance information and performing comparison under the same conditions as the reflectance information may be used. However, the reflectance information can also be converted to the same conditions as the theoretical reflectance information.

The comparison determination module 164 is configured to compare the reflectance information obtained by the transmitted light detecting unit 140 with the theoretical reflectance information converted by the storage module 162 and the conversion module 163 to determine the thickness of the measurement target.

That is, the reflectance information obtained by the transmitted light detecting portion 140 is compared with the theoretical reflectance information to retrieve the most similar theoretical reflectance information, and the most similar theoretical reflection is obtained when the most similar theoretical reflectance information is retrieved. The thickness value corresponding to the degree is determined as the thickness of the measurement object.

Next, an operation mode of the embodiment of the above-described thickness measuring device and the thickness measuring method using the same will be described.

Please refer to the fifth figure, which is a flow chart of the thickness measurement method of the present invention; as shown in the fifth figure, the thickness measurement method of the embodiment adjusts the reflectance of the reflectance information so as to have a suitable and theoretical reflectance. The information is compared to the reflectance, so that the accuracy of the thickness measurement can be improved, including: a modulation step S110, a theoretical reflectance information setting step S120, a conversion step S125, a reflectance information acquisition step S130, a matching step S140, and a thickness. The step S150 is determined.

The modulating step S110 is a step of setting a plurality of frequencies of the transmissive filter portion 120 such that the light emitted from the light source 110 has an intensity distribution and adjusts a wavelength width thereof when modulated by the filter unit 120.

Here, the wavelength width is determined by the number of light waves and the frequency value emitted from the light wave generating portion 121, and is related to the reflectance value of the reflectance information obtained in the obtaining step S140 of the reflectance information to be described later.

The sixth A-B graph is a graph of the light intensity before and after the wavelength modulation step in the thickness measurement method of the fifth graph, and the seventh graph is the reflectance information graph obtained based on the light before and after the modulation step in the thickness measurement method of the fifth graph. As can be seen from the sixth A-B diagram and the seventh diagram, as the modulation step S110 is performed, the intensity of the light and the reflectance value in the reflectance information will change accordingly.

Further, in the embodiment of the present invention, the number of the light wave generating portions 121 that emit light waves in the plurality of light wave generating portions 121, that is, the number of the light wave generating portions 121 that operate, can be determined, and the light wave generating portion from the operation can be separately determined. The light wave frequency emitted by 121 is used to perform the modulation step S110, but is not limited thereto.

In the present embodiment, the three light wave generating units 121 are operated by the modulation step S110, and the light waves emitted from the respective light wave generating units 121a, 121b, and 121c have frequencies of 120 MHz, 130 MHz, and 140 MHz, respectively. Further, in the present embodiment, the light waves emitted from the respective light wave generating portions 121 are set to be larger in size as they are farther away from the light source 110. However, the present invention is not limited thereto, and may be configured such that the size thereof becomes smaller in order. Or irregular.

Further, in the light waves emitted from the respective light wave generating portions 121, the larger the difference between the minimum value and the maximum value, the wider the intensity distribution of the modulated light, and the smaller the difference between the minimum value and the maximum value. Modulated light The narrower the intensity distribution. Further, according to the present embodiment, the light wave emitted from each of the light wave generating portions 121 is set to be stably increased by 10 MHz as it is away from the light source 110, but the present invention is not limited thereto.

The step S120 of the theoretical reflectance information is a step of storing theoretical reflectance information in the save module 162 through mathematical modeling, and includes a modeling step S124 and a converting step S125.

Further, according to the present embodiment, the theoretical reflectance information determines the light having a fine wavelength width of a specific frequency as the intensity value of the initial light, but is not limited thereto. Further, in the above description, the modulating step S124 is described as a step of determining the theoretical reflectance distribution curve and the theoretical integrated reflectance distribution curve, and thus detailed description is omitted here.

8A to 8C are diagrams of conversion steps in the thickness measurement method shown in FIG. 5; wherein, the eighth diagram A shows a schematic diagram in which the intensity of light is changed through the modulation step, and the eighth B diagram A graph showing that the reflectance information and the theoretical reflectance information become different from each other at the same thickness as the light intensity changes, and the eighth C map shows the reflectance information and the theoretical reflectance at the same thickness through the conversion step. A schematic diagram where the information becomes consistent.

As shown in the eighth figure, the converting step S125 is a conversion when the light is modulated by the modulating step S110 to have a light value different from the intensity value of the initial light set in the setting step S120 of the theoretical reflectance information. The step of theoretical reflectivity information. As stated above, theoretical reflectivity The information obtains a theoretical integrated reflectance distribution curve based on the light intensity value set in the setting step S120 of the theoretical reflectance information.

Here, if the set intensity value is changed, the preconditions for comparing the theoretical reflectance information and the reflectance information become inconsistent, and therefore the accuracy of the thickness determination cannot be expected. Therefore, it is necessary to convert the theoretical reflectance information on the basis of the changed intensity value, or to convert the reflectance information into the initial intensity value. In the present embodiment, the theory is based on the changed intensity value. Reflectance information is converted.

The step S130 of acquiring the reflectance information is a step of receiving the light reflected by the measuring object S from the light detecting unit 140 to acquire a reflectance distribution curve. In the reflectance information acquisition step S130, the transmitted light detecting unit 140 acquires the reflectance distribution curve as a well-known technique, and thus detailed description thereof will be omitted.

The matching step S140 compares the theoretical reflectance information obtained through the setting step S120 of the theoretical reflectance information with the reflectance information obtained by the obtaining step S130 of the reflectance information to retrieve the theoretical reflection most similar to the reflectance information. Steps to information.

For the most similarity, the judgment is made by the following method: after the error function using the least-square method is obtained, the theoretical reflectance information and the reflectance information with the smallest error are judged as "most similar"; however, this method is a well-known technique. Therefore, a detailed description is omitted here. Of course, not only through the multiplication method as described above, but also through other methods to determine whether it is "the most Like "."

Further, the reflectance value of the reflectance information measured by the light detecting portion 140 may be too low or too high, so that comparison or difficulty in comparison is impossible in the matching step S140. In this case, the modulation step S110 will be performed again. If the reflectance value of the measured reflectance information is too low, the value and the number of the frequency are reset in the modulation step S110 to make the intensity of the light. The wavelength width of the distribution is widened; if the reflectance value of the measured reflectance information is too high, the value and the number of the frequency are reset in the modulation step S110 to narrow the wavelength width of the intensity distribution of the light.

That is, the reflectance value is processed by re-performing the modulation step S110 so that the reflectance information and the theoretical reflectance information can be easily compared in the subsequent matching step S140.

Here, the theoretical reflectance information is re-acquired based on the value changed by the re-execution of the modulation step S110, and then saved, and then the matching step S140 is performed again to retrieve the theoretical reflectance information most similar to the reflectance information.

In the thickness determining step S150, the theoretical reflectance information most similar to the reflectance information is selected, and the thickness corresponding to the selected theoretical reflectance information is determined as the thickness of the measuring object.

Further, by dividing the inspection surface of the measuring object S into a plurality of regions of a micrometer or a nanometer size, and examining each region and combining the measured results, the thickness and the three-dimensional shape of the surface including the measuring object S can be calculated. The comprehensive information of the inspection surface of the measuring object S is visualized and visualized.

It is to be understood that the scope of the invention is not limited to the embodiments described above, but may be embodied in various forms within the scope of the appended claims. The various ranges in which the person having ordinary knowledge in the art to which the present invention pertains can be modified are also within the scope of the present invention without departing from the spirit and scope of the invention as claimed.

S‧‧‧Measurement object

100‧‧‧ thickness measuring device

110‧‧‧Light source

120‧‧‧Filter Department

130‧‧‧Optical system

140‧‧‧Light Inspection Department

150‧‧‧ camera department

160‧‧‧Control Department

S100‧‧‧ thickness measurement method

S110‧‧‧Modulation step

S120‧‧‧Setting steps for theoretical reflectance information

S130‧‧‧Steps for obtaining reflectance information

S140‧‧‧ Matching steps

S150‧‧‧ thickness determination step

Claims (9)

A thickness measuring device for measuring by using a Reflectometer includes: a light source for emitting light; and a filter portion for receiving light emitted by the light source, and Selectively transmitting a plurality of different frequencies such that the light is modulated into light having an intensity distribution, and the filter portion is capable of adjusting a wavelength width of the light having the intensity distribution; an optical system to the measuring object side Light modulated by the filter portion is irradiated, and light reflected from the measuring object side is incident into the optical system; a light detecting portion is configured to receive light passing through the optical system Obtaining reflectance information; and a control portion configured to set a plurality of frequencies transmittable to the filter portion to adjust a wavelength width of light modulated by the filter, and to transmit a mathematical expression The theoretical reflectance information that has been modeled and saved is compared with the reflectance information obtained by the light detecting portion, and the thickness of the measuring object is measured. The thickness measuring device according to claim 1, wherein the filter portion is a plurality of acousto-optic modulation filters (Acousto-Optical Tunable) configured to be spaced apart from each other in a direction in which light rays are emitted from the light source. Filter: AOTF). The thickness measuring device according to claim 2, wherein the filter portion combines the light while maintaining a wavelength of light that transmits the plurality of frequencies that have been set, respectively, and further The light transmitted by the filter portion is modulated into light having an intensity distribution. The thickness measuring device of claim 1, wherein the optical system comprises: a first beam splitter for reflecting light modulated by the filter portion or reflecting from the measuring object Light is transmitted; and a lens portion is disposed between the first beam splitter and the measurement object for condensing light reflected from the first beam splitter toward the measurement object side; wherein the thickness measuring device Further comprising: a camera portion for receiving light reflected from the measurement object from the optical system to obtain image information of the measurement object. The thickness measuring device of claim 1, wherein the control unit comprises: a frequency setting module for setting a plurality of frequencies transmittable to the filter portion; a save module for storing a plurality of theoretical reflectance information that is modeled by a mathematical expression and corresponding to each thickness; and a comparison judgment module for the reflectance information measured by the light detecting portion The theoretical reflectance information stored in the save module is compared to determine the thickness of the measurement object. The thickness measuring device of claim 5, wherein the control unit further comprises: a conversion module for converting a frequency adjusted by the frequency setting module, converting the light by the light At least one of the reflectance information measured by the detecting unit and the theoretical reflectance information stored in the saving module, and the comparison determining module uses the reflectance information and the theoretical reflectance information At least one piece of information that has been converted to measure the thickness of the measurement object. A thickness measuring method comprising the steps of: (1) a modulating step of setting a plurality of frequencies transmissive for a filter portion for modulating light emitted from a light source to adjust modulation through the filter portion The wavelength width of the intensity distribution of the light; (2) the step of setting the theoretical reflectance information, setting the theoretical reflectance information corresponding to each thickness through a mathematical formula; (3) the step of acquiring the reflectance information, illuminating the side of the measuring object The light modulated by the filter portion to obtain the reflectance of the measuring object (4) a matching step of comparing the theoretical reflectance information with the reflectance information to select theoretical reflectance information most similar to the reflectance information in the theoretical reflectance information; and 5) A thickness determining step of determining a thickness corresponding to the theoretical reflectance information selected in the matching step as the thickness of the measurement object. The thickness measuring method of claim 7, wherein the step of setting the theoretical reflectance information comprises: a converting step of considering a plurality of frequencies set by the modulating step, and transmitting the theory The theoretical reflectance information set by the reflectance setting step is converted. The thickness measuring method of claim 8, wherein the modulating step is performed again when the theoretical reflectance information most similar to the reflectance information cannot be selected in the matching step.