JP5733846B2 - Apparatus and method for measuring thickness using digital optical technology - Google Patents

Description

  The present invention relates to a thickness measuring apparatus and method using digital optical technology, and more specifically, reflects light transmitted from a beam splitter through a reflective optical path conversion unit to minimize optical loss. The present invention relates to a thickness measuring apparatus and method using a digital optical technique that can measure the thickness of a plurality of points simultaneously by adjusting the reflection angle.

  In the semiconductor process and the FPD process, since the specific gravity of the control of the thickness of the thin film layer is large among various factors that determine the quality, it can be said that it is essential to directly monitor this in the process. The “thin film layer” generally refers to a base layer, that is, a layer having a very fine thickness formed on the surface of a substrate and generally having a thickness of several nm to several μm. In order to apply these thin film layers to specific applications, it is necessary to know the thickness, composition, illuminance, and other physical and optical characteristics of the thin film layers.

  In particular, in recent years, in order to increase the degree of integration of semiconductor elements, it is a general tendency to form an ultrathin film layer on a substrate in multiple layers. In order to develop such a highly integrated semiconductor device, the physical properties of the film including the thickness of the thin film layer, which is a factor that greatly affects the characteristics, must be accurately controlled.

  A conventional thickness measuring apparatus has a configuration in which light transmitted from a beam splitter is incident on a spectroscope after passing through an LCD that transmits the light.

  In such a conventional invention, a loss occurs when light passes through the LCD, and there is a possibility that accurate information on the thickness of the measurement object cannot be obtained.

  Also, when attempting to obtain thickness information for a part of the measurement object, the entire measurement object must be irradiated, and one measurement object has a thin film structure for each measurement region. If they are different, a plurality of measurements are required, which causes a problem that the measurement time increases.

  Accordingly, an object of the present invention is to solve such a conventional problem, and a digital optical technique capable of minimizing light loss by using light reflection is used. It is to provide a thickness measuring apparatus and method.

  Digital optical technology that can control the thickness of multiple measurement areas at the same time by controlling the reflection-type optical path converter and making light incident from different measurement areas enter different spectrometers An object of the present invention is to provide a thickness measuring apparatus and method using the above.

  The object is to provide a light source that emits light, a beam splitter that reflects light emitted from the light source or transmits light reflected by a measurement object, and the light reflected by the beam splitter according to the present invention. The thickness of the object to be measured by analyzing the light reflected from the lens unit for focusing on the object, the reflection type optical path conversion unit for selectively reflecting the light transmitted from the beam splitter, and the reflection type optical path conversion unit This is achieved by a thickness measuring device using digital optical technology characterized in that it includes a spectrograph for acquiring information.

  Here, it is desirable that a plurality of spectrometers are provided, and the reflection-type optical path converter reflects light reflected from a plurality of different measurement regions of the measurement object to each spectrometer.

  In addition, the display device may further include a display unit that displays an image of the measurement object on the basis of the light transmitted from the beam splitter.

  Here, it is preferable that the display unit displays an image of the measurement object in response to an input of the light reflected from the reflection type optical path conversion unit.

  In addition, the display unit further includes an auxiliary beam splitter disposed on the optical path between the beam splitter and the reflective optical path conversion unit to reflect or transmit light transmitted from the beam splitter, and the display unit transmits from the auxiliary beam splitter. In response to the input light, an image of the measurement object can be displayed.

  Here, the light absorption part which absorbs and removes light other than the light reflected by the spectroscope from the reflection type optical path conversion part can be further included.

  In addition, using the thickness measuring apparatus using the above digital optical technology, an image storage stage for storing an image of an object to be measured, an image stored in the image storage stage and a video displayed on the display unit are compared. A matching stage for determining whether the measurement area is displayed on the display unit, and the reflection type optical path conversion unit so that light reflected from a plurality of different measurement areas is reflected by the plurality of spectrometers. The present invention is achieved by a thickness measurement method including a reflection angle adjustment step of adjusting a reflection angle, and a thickness measurement step of measuring the thickness of the measurement object with reference to light acquired by a spectroscope.

  In addition, the matching step is repeated until the entire measurement area is displayed on the display unit. When only a part of the measurement area is displayed on the display unit, the entire measurement area is displayed on the video displayed on the display unit. If the measurement area is not displayed on the display unit after moving the measurement object so that the matching stage is performed again, and the measurement area is not displayed on the display unit, the measurement object or the lens unit is arranged on the display unit along the spiral direction. May include a measurement region search step in which the matching step is re-executed after being moved until part or all of is displayed.

  Here, in the thickness measurement stage, the reflectance measurement stage for measuring the reflectance of light from the spectrum of light obtained from the spectroscope is compared with the reflectance provided by theoretical modeling, A reflectivity comparison step that searches for the most similar modeling and a thickness output step that outputs a thickness value corresponding to the modeling searched in the reflectivity comparison step may be included.

  According to the present invention, there is provided a thickness measuring apparatus and method using a digital optical technique capable of improving the measurement efficiency by minimizing the loss of light by utilizing the reflection of light.

  Moreover, even if the thin film structure of the measurement region is different, the thickness of the measurement region is changed by controlling the minimal mirror of the reflection type optical path changing unit so that the light reflected from the different measurement regions is incident on each spectroscope. Can be measured simultaneously.

  In addition, an image of the measurement object measured from the thickness measurement device can be visually confirmed via the display unit.

  Further, light other than the light reflected from the reflective light path conversion unit to the spectroscope through the light absorption unit can be absorbed and removed.

  Further, when the entire measurement area does not exist within the measurement range, the measurement efficiency can be improved by changing the position of the lens unit or the measurement object so that the entire measurement area is automatically included.

1 is a conceptual diagram schematically showing a thickness measuring apparatus using digital optical technology according to a first embodiment of the present invention. It is the conceptual diagram which showed roughly a mode that the reflection angle of a reflection type optical path conversion part was changed with the thickness measuring apparatus using the digital optical technique of FIG. FIG. 1 schematically shows a state in which the reflectivity in two measurement regions having different thin film structures is measured by changing the reflection angle of a partial region of the reflection type optical path conversion unit with the thickness measurement apparatus using the digital optical technique of FIG. It is the figure shown, Comprising: It is the conceptual diagram which showed schematically a mode that light was reflected by three apparatuses simultaneously with a digital micromirror. FIG. 1 schematically shows a state in which the reflectivity in two measurement regions having different thin film structures is measured by changing the reflection angle of a partial region of the reflection type optical path conversion unit with the thickness measurement apparatus using the digital optical technique of FIG. It is the figure shown, Comprising: It is the top view which showed the mode of the measuring object roughly. FIG. 1 schematically shows a state in which the reflectivity in two measurement regions having different thin film structures is measured by changing the reflection angle of a partial region of the reflection type optical path conversion unit with the thickness measurement apparatus using the digital optical technique of FIG. FIG. 3 is a schematic view showing a thin film structure of a first measurement region and a second measurement region. FIG. 1 schematically shows a state in which the reflectivity in two measurement regions having different thin film structures is measured by changing the reflection angle of a partial region of the reflection type optical path conversion unit with the thickness measurement apparatus using the digital optical technique of FIG. It is the figure shown, Comprising: It is the bottom view which showed roughly a mode that a reflectance was controlled differently for every area | region with a digital micromirror. FIG. 1 schematically shows a state in which the reflectivity in two measurement regions having different thin film structures is measured by changing the reflection angle of a partial region of the reflection type optical path conversion unit with the thickness measurement apparatus using the digital optical technique of FIG. It is the figure shown, Comprising: It is a graph which shows the reflectance curve after measuring simultaneously 2 area | regions where the thin film structures differed. It is the conceptual diagram which showed roughly the thickness measuring apparatus using the digital optical technique which concerns on 2nd Embodiment of this invention. 3 is a flowchart schematically showing a thickness measuring method using the digital optical technique according to the first embodiment of the present invention. 6 is a flowchart schematically showing a matching step in the thickness measuring method using the digital optical technique of FIG. 5. FIG. 7 is a conceptual diagram schematically showing a direction in which a measurement area is searched in the measurement area search stage of FIG. 6.

  Before the description, in some embodiments, components having the same configuration will be described in the first embodiment using the same reference numerals, and other embodiments are different from the first embodiment. The configuration will be described.

  Hereinafter, a thickness measuring apparatus and a measuring method using a digital optical technique according to a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a conceptual diagram schematically showing a thickness measuring apparatus using digital optical technology according to a first embodiment of the present invention.

  Referring to FIG. 1, a thickness measurement apparatus using digital optical technology according to the first embodiment of the present invention includes a light source 110, a beam splitter 120, a lens unit 130, a reflective optical path conversion unit 140, and a spectrometer 150. Display unit 160.

  The light source 110 emits light for measuring the thickness of the measurement object 105, and various sources of lamps including a halogen lamp can be used. Moreover, although it can be provided as a white light source, it is not limited to this.

  The beam splitter 120 reflects light incident from the light source 110 so as to be incident on a lens unit 130 described later, or transmits light reflected from the measurement object 105, thereby reflecting light described later. The optical path is guided so as to enter the path conversion unit 140.

  The lens unit 130 focuses the light reflected from the beam splitter 120 on the measurement target 105. Since the specific configuration of the lens unit 130 is a well-known technique, a detailed description thereof is omitted here.

  The reflection type optical path conversion unit 140 reflects the light transmitted from the beam splitter 120, which is light having thickness information of the measurement target 105, so as to enter the spectroscope 150 or the display unit 160 described later. Guide the light path. Each of the surfaces where reflection occurs in the reflection-type optical path conversion unit 140 is provided with a minimum mirror that can be individually controlled, and the reflection angle of light can be adjusted. According to the first embodiment 100 of the present invention, the reflection-type optical path conversion unit 140 is provided with a digital micromirror device (DMD), but is not limited to this. All devices that can be reflected to have a different angle each can be included here.

  FIG. 2 is a conceptual diagram schematically showing how the reflection angle of the reflection type optical path conversion unit is changed in the thickness measuring apparatus using the digital optical technique of FIG. 1, and FIG. 3 is a digital diagram of FIG. A schematic illustration of the measurement of reflectivity in two measurement areas with different thin-film structures by changing the reflection angle of a partial area of the reflective optical path changer with a thickness measurement device using optical technology It is drawing, (a) is the conceptual diagram which showed the mode that the light was reflected by three apparatuses simultaneously with a digital micromirror, (b) showed the mode of the measuring object roughly It is a plan view, (c) is a cross-sectional view schematically showing the thin film structure of the first measurement region and the second measurement region, (d) is a digital micromirror, the reflectivity of each region is different (E) is a bottom view schematically showing the state of control, and (e) shows the reaction after two regions with different thin film structures are measured simultaneously. It is a graph which shows an emissivity curve.

  In other words, it is possible to adjust the reflection angles of the mirrors of the reflection type optical path conversion unit 140 so that they are all the same, and the mirrors of the reflection type optical path conversion unit 140 may be adjusted to have different reflection angles. can do. In particular, even if there are a plurality of different regions to be measured on the measurement object 105 by adjusting the reflection angles to be different from each other, the mirror of the reflective optical path conversion unit 140 corresponding to the corresponding region Can be adjusted to be incident on each spectroscope 150. As a result, even if the thin film structure is different for each of a plurality of different regions existing on the measurement object 105, the light reflected in each region can be analyzed simultaneously by the separate spectroscope 150. It becomes.

  The spectroscope 150 is a device that detects the spectrum of light reflected from the measurement object 105. According to the first embodiment 100 of the present invention, the first spectroscope 151 and the second spectroscope 152 are included. However, the present invention is not limited to this, and three or more spectroscopes may be installed according to the needs of the user. It is possible to provide a configuration.

  Referring to FIG. 3A, the first spectrometer 151 is disposed on an optical path where light is reflected from the reflective optical path converter 140 at a reflection angle of 100 °. Are arranged on an optical path in which light is reflected from the reflection type optical path conversion unit 140 at a reflection angle of 80 °. However, the angle is not limited to this, and it is sufficient that the spectroscopes 150 are arranged on the optical paths having different reflection angles from the reflection type optical path conversion unit 140.

  For example, when the first measurement area 106 and the second measurement area 107 existing on the measurement object 105 are measured simultaneously as shown in FIG. 3B, the first measurement area 106 is shown in FIG. The first reflection part 141 on the reflection type optical path conversion unit 140 corresponding to the measurement area 106 is controlled to form a reflection angle of 100 °, and the second reflection part 142 corresponding to the second measurement area 107 is 80 °. The light reflected from the first measurement region 106 and the first reflection unit 141 is controlled to form a reflection angle, is incident on the first spectrometer 151, and is reflected from the second measurement region 107 and the second reflection unit 142. The light is incident on the second spectrometer 152. As a result, as shown in FIG. 3C, even when the thin film structures of the first measurement region 106 and the second measurement region 107 are different, as shown in FIG. Since the light spectrum can be measured simultaneously with the 151 and the second spectroscope 152, the thicknesses in the two regions can be measured simultaneously.

  The display unit 160 is an apparatus that captures the shape of the measurement target 105 and provides an image to the outside. The area photographed by the display unit 160 is the same as the measurement area in which the thickness is to be measured in the first embodiment 100 of the present invention, and the area photographed by the display unit 160 in the matching step (S120) described later. The stored images of the measurement object 105 can be compared to determine whether the measurement area is included in the measurement range of the first embodiment 100 of the present invention.

  The arrangement of the first exemplary embodiment 100 of the present invention will be described in detail with reference to the optical path of light emitted from the light source 110. Light is emitted from the light source 110, reflected by the beam splitter 120, and passed through the lens unit 130. To do. The light that has passed through the lens unit 130 is incident on the measurement object 105 and then reflected and passes through the beam splitter 120.

  The light transmitted from the beam splitter 120 enters the reflection type optical path conversion unit 140, is reflected, and then enters the spectroscope 150 or the display unit 160.

  On the other hand, a condensing lens is provided between the beam splitter 120 and the reflection type optical path conversion unit 140 so that the light transmitted from the beam splitter 120 is focused and incident on the reflection type optical path conversion unit 140 side. However, it is not limited to this.

  Further, an optical fiber that guides the optical path or a focusing lens that focuses the light incident on each spectroscope 150 may be provided between the reflective optical path converter 140 and the spectroscope 150. It is not limited to.

  From now on, the operation method (S100) of the first embodiment of the thickness measuring apparatus using the digital optical technique described above will be described.

  FIG. 5 is a flowchart schematically showing a thickness measuring method using the digital optical technique according to the first embodiment of the present invention, and FIG. 6 is a thickness measuring method using the digital optical technique of FIG. FIG. 7 is a conceptual diagram schematically showing the direction in which the measurement area is searched in the measurement area search stage of FIG.

  Referring to FIG. 5, the thickness measuring method (S100) using the digital optical technique according to the first embodiment of the present invention includes an image storage step (S110), a matching step (S120), and a reflection angle adjustment step (S130). And the thickness measuring step (S140), and by performing these processes, the thickness of the measuring object 105 can be measured.

  The image storage step (S110) is a step of storing an image of the measurement object 105 before measuring the thickness in order to recognize the measurement region. That is, the image itself obtained by photographing the area including the measurement area on the measurement object 105 with the optical system is stored as a standard model and used in the matching stage (S120) described later.

  In the matching step (S120), the standard model stored in the image storage step (S110) is compared with the video imaged on the display unit 160, and the measurement region is within the measurement range of the first embodiment 100 of the present invention. It is the stage which judges whether it is included in.

  Referring to FIG. 6, the matching step (S120) is preferably repeated until the measurement area is completely displayed on the display unit 160. In the case where only a part of the measurement area is displayed on the display unit 160 or not displayed at all. The centering step (S121) or the measurement area search step (S122) is performed.

  The centering step (S <b> 121) is performed when only a part of the measurement region is displayed on the display unit 160, and the measurement object 105 or the lens unit 130 is configured to display all the measurement region on the display unit 160. This is the stage to move the position.

  According to the first embodiment 100 of the present invention, the centering step (S121) compares the standard model stored in the image storage step (S110) with the image displayed on the display unit 160 to determine the currently measured position. Calculation is performed, the difference between the position and the measurement area is calculated using the calculated position value, and the measurement object 105 or the lens unit 130 is moved.

  Referring to FIG. 7, the measurement region search step (S122) is performed when no measurement region is displayed on the display unit 160, and it is difficult to use the standard model stored in the image storage step (S110). Will do this process.

  The measurement region search step (S122) is a step of searching the measurement region by moving the position of the measurement object 105 or the lens unit 130 along the circumferential direction in the region closest to the region displayed on the display unit. According to the first embodiment 100 of the present invention, when the measurement area is not displayed on the display unit 160, the measurement object 105 or the lens unit 130 is moved along the counterclockwise direction to capture an image. Note that an image may be taken by moving the measuring object 105 or the lens unit 130 along the clockwise direction.

  Here, the measurement area is repeatedly performed until all or a part of the measurement area is displayed on the display unit 160. When all the part of the measurement area is displayed, the reflection angle adjustment step (S130) is performed. Will perform the centering step (S121).

  On the other hand, when the measurement region is two or more regions, the above-described matching step (S120) is performed in the same manner. When all of the plurality of measurement regions can be included in the measurement range, the matching step (S120) is performed until all of the plurality of measurement regions are included in the measurement range. In other words, the matching step (S120) is performed separately for each measurement region.

  Referring to FIG. 2, in the reflection angle adjustment step (S 130), the reflection angle of the reflection type optical path conversion unit 140 is adjusted so that the light reflected from the measurement region enters the spectroscope 150. That is, when the reflection angle of the reflection type optical path changing unit 140 is adjusted by 100 °, light is incident on the first spectrometer 151, and when the reflection angle is adjusted by 80 °, light is incident on the second spectrometer 152.

  Further, referring to FIG. 3, the same applies to the case where the measurement region is two regions and light is incident on two spectroscopes 150 at the same time. As described above, the reflection surface of the reflection-type optical path conversion unit 140 includes a plurality of minimal mirrors, and each mirror can be individually controlled. Utilizing this, when the reflection angle of the first reflection unit 141 is adjusted to 100 ° and the reflection angle of the second reflection unit 142 is adjusted to 80 °, the light reflected from the first measurement region 106 is The light incident on the spectroscope 151 and reflected from the second measurement region 107 enters the second spectroscope 152. Of course, not only when the measurement area is two areas, but also when there are three or more areas, the spectroscope 150 is further added to change the reflection angle of a part of the reflection type optical path conversion unit 140 to the first reflection surface 141 and It can be formed so as to have a reflection angle different from the reflection angle of the second reflection surface, and the thickness can be measured at the same time.

  In the thickness measuring step (S140), the spectrum of the light incident on the spectroscope 150 is measured to measure the reflectivity (reflection spectrum) of the light, and the thickness of the measuring object 105 is measured based on this. It is a stage. According to the first embodiment (S100) of the present invention, the thickness measurement step (S140) includes a reflectivity measurement step (S141), a reflectivity comparison step (S142), and a thickness output step (S143). . However, the thickness measurement step (S140) is not limited to the above-described step.

  In the reflectivity measurement step (S141), the spectrum of the light incident on the spectroscope is analyzed, and the reflectivity of the measurement region is calculated using the light amount data for each wavelength of the light.

  In the reflectance comparison step (S142), the reflectance of the measurement region obtained in the reflectance measurement step (S141) is the same as or not identical to the reflectance obtained in the theoretical modeling. The case is the stage of searching for the modeling with the most similar reflectivity.

  The thickness output step (S143) is a step of outputting a thickness value corresponding to the modeling searched in the reflectivity comparison step (S142).

  In the thickness measurement method (S100) according to the first embodiment of the present invention, the matching step (S120) is performed so that the measurement region is included in the measurement range, and the accuracy of thickness measurement is improved. In the case of automation, the effect can be further improved.

  Further, it is possible to adjust the reflection angles of all the minimal mirrors included in the reflection type optical path conversion unit 140, or to adjust only a part of the reflection angles. Since the thickness of the measurement area can be measured simultaneously, the measurement time can be shortened.

  Next, a thickness measuring apparatus and method using digital optical technology according to the second embodiment of the present invention will be described.

  FIG. 4 is a conceptual view schematically showing a thickness measuring apparatus using digital optical technology according to the second embodiment of the present invention.

  Referring to FIG. 4, a thickness measuring apparatus 200 using digital optical technology according to the second embodiment of the present invention includes a light source 110, a beam splitter 120, a lens unit 130, and a reflective optical path changing unit (Digital Micromirror Device, (Hereinafter referred to as “reflection type optical path conversion unit”) 140, spectroscope 150, display unit 160, auxiliary beam splitter 225, and light absorption unit 270.

  The auxiliary beam splitter 225 is disposed on the optical path between the beam splitter 120 and the reflection type optical path conversion unit 140 to reflect the light transmitted from the beam splitter 120 to the display unit 160 side, or to reflect light. The light is transmitted to the path conversion unit 140 side.

  That is, unlike the first embodiment, the auxiliary beam splitter 225 is not disposed and the light reflected by the reflection-type optical path converter 140 is not incident on the display unit 160, but the beam splitter via the auxiliary beam splitter 225. The light transmitted at 120 is reflected to the display unit 160 side.

  The display unit 160 is provided with the same configuration as the display unit 160 in the first embodiment 100, but the position where the light reflected from the reflective optical path conversion unit 140 is incident as in the first embodiment 100. Rather than being disposed at a position where the light reflected from the auxiliary beam splitter 225 is incident. With this arrangement, the display unit 160 is not affected by the reflection angle of the reflection type optical path conversion unit 140 and always displays an image for the measurement range.

  The light absorption unit 270 is a device that absorbs and removes light other than the light reflected from the reflective light path conversion unit 140 to the spectroscope 150. This is because the reflection type optical path conversion unit 140 forms the first reflection unit 141 and the second reflection unit 142, and at the same time, the first spectroscope 151 or the second spectroscope 152 in the first measurement region 106 or the second measurement region 107. In the case of reflecting the reflected light, the light reflected by the surface other than the first reflecting part 141 or the second reflecting part 142 of the reflective optical path changing part 140 is reflected by the light absorbing part to remove the light. Become.

  Since the operation method (S200) of the second embodiment of the thickness measuring apparatus using the digital optical technique described above is the same as the operation method (S100) of the first embodiment, detailed description thereof is omitted. That is, the second embodiment 200 changes the position of the measurement object 105 from the light before entering the reflective optical path conversion unit 140, and absorbs and removes the light reflected from other than the measurement region. A part 270 is added, only the arrangement of each component is different, the function is the same as in the first embodiment 100, and the method for measuring the thickness of the measurement object 105 is the same.

  The scope of rights of the present invention is not limited to the above-described embodiments, and can be embodied in various forms of embodiments within the scope of the appended claims. Without departing from the gist of the present invention claimed in the scope of claims, any person having ordinary knowledge in the technical field to which the invention pertains can describe various claims that can be modified. Considered to be within range.

DESCRIPTION OF SYMBOLS 100 Thickness measurement apparatus 110 Light source 120 Beam splitter 130 Lens part 140 Reflection type optical path conversion part 150 Spectroscope 160 Display part 200 Thickness measurement apparatus 225 Auxiliary beam splitter 270 Light absorption part S100 Thickness measurement method S110 Image preservation | save stage S120 Matching Step S121 Centering step S122 Measurement area search step S130 Reflection angle adjustment step S140 Thickness measurement step S141 Reflectivity measurement step S142 Reflectivity comparison step S143 Thickness output step

Claims (6)

A light source that emits light;
A beam splitter that reflects light emitted from the light source or transmits light reflected by the measurement object;
A lens unit that focuses the light reflected by the beam splitter onto the measurement object;
In response to the provision of the light transmitted from the beam splitter, the light reflected from the different measurement regions of the measurement object can be mutually measured so that the thickness measurement in a plurality of regions of the measurement object can be performed at the same time. A reflective optical path conversion unit that reflects along different optical paths;
A plurality of spectroscopes for analyzing the light reflected from the reflection type optical path conversion unit and obtaining thickness information of the measurement object;
Based on the light transmitted from the beam splitter receives an input of light reflected from the reflection type optical path changing unit, seen including a display unit for displaying an image of the object to be measured,
The display unit determines whether the measurement region of the measurement object is displayed on the display unit by comparing the image of the measurement object and the image displayed on the display unit,
The reflection-type light path conversion unit adjusts the reflection angle of the reflection-type light path conversion unit, and reflects light reflected from a plurality of different measurement regions of the measurement object to each spectroscope. Thickness measurement device using the featured digital optical technology. An auxiliary beam splitter that is disposed on an optical path between the beam splitter and the reflective optical path converter, and reflects or transmits light transmitted from the beam splitter;
The thickness measuring apparatus using digital optical technology according to claim 1 , wherein the display unit receives an input of light transmitted from the auxiliary beam splitter and displays an image of the measurement object. The digital optical technique according to claim 1 , further comprising a light absorption unit that absorbs and removes light other than light incident on the spectroscope from the reflection type optical path conversion unit. Thickness measuring device. Utilizing a thickness measuring device using the digital optical technique according to claim 2 or 3 ,
An image storage step for storing an image of the measurement object;
A matching step of comparing the image stored in the image storage step with the image displayed on the display unit to determine whether the measurement region of the measurement object is displayed on the display unit;
A reflection angle adjusting step of adjusting a reflection angle of the reflective optical path conversion unit so that light reflected from the plurality of different measurement regions is incident on the plurality of spectrometers, respectively.
A thickness measurement step for measuring the thickness of the measurement object based on the light acquired by the spectrometer;
A thickness measuring method comprising: The matching step is repeated until the measurement area is completely displayed on the display unit,
When only a part of the measurement area is displayed on the display unit, after moving the measurement object or the lens unit so that the entire measurement area is displayed on the image displayed on the display unit, A centering step for re-performing the matching step, and when the measurement region is not displayed on the display unit, the measurement object or the lens unit is partially or entirely displayed on the display unit along the spiral direction. The method of claim 4 , further comprising: a measurement region search step of performing the matching step again after moving to a predetermined position. In the thickness measurement step, a reflectivity measurement step of measuring light reflectivity from a spectrum of light acquired from the spectroscope is compared with the measured reflectivity and the reflectivity provided by theoretical modeling. the most similar reflectance comparing step to find the model, according to claim 4 or 5, characterized in that it comprises a thickness output step of outputting the thickness value corresponding to the searched by the reflectivity comparing step Modeling The thickness measuring method as described in.

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