JPH1047926A - Device for measuring film thickness and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film thickness measuring device wherein shorter measurement time and smaller and lower cost device is realized. SOLUTION: A light L1 from a light source part 2 is projected on a substrate 91 through a filter 43 which allows the light of a specific wave length to pass, and the reflected light L2 from the substrate 91 is photo-detected with a photo- detecting means 5 comprising multiple photo-detecting elements arrayed in 2-dimension. Kind of the filter 43 is changed by using a changing means 4, so that lights of different wavelengths are projected in order on the substrate 91. Thereby, the 2-dimension space distribution information on the light quantity of reflected light when the lights of multiple wavelengths are projected in order on the substrate is sent to a processing part 6 sequentially, and based on the information, the film thickness at the area of the substrate 91 where the light L1 is poured is collectively obtained. As a result, such means as moving of the substrate 91 not required, shorter measurement time and smaller and lower- cost device is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass substrate used for manufacturing an FPD (Flat Panel Display) such as a semiconductor substrate or a liquid crystal display (hereinafter, referred to as a "substrate").
And a method for measuring the thickness of a thin film formed on the substrate based on the reflected light from the substrate.

[0002]

2. Description of the Related Art The thickness of a thin film formed on a semiconductor substrate or a glass substrate greatly affects the quality of a semiconductor device or a liquid crystal display manufactured from such a substrate. It has become.

As one method of measuring the thickness of this thin film, there is a method of irradiating a substrate with light and calculating the thickness based on the amount of light reflected from the substrate for each wavelength. FIG. 10 is a view showing a conventional example of an apparatus for measuring the thickness of a thin film formed on a substrate using such light.

In this film thickness measuring device 101, the light source unit 10
White light L101 emitted from the second mirror 131
Then, the light is condensed on the condensing point SP101 on the substrate 109 via the objective lens 132, and the reflected light L102 reflected on the substrate 109 is separated using the concave diffraction grating 133,
The light is received by the light receiving unit 105. The light receiving means 105 is composed of a plurality of light receiving elements arranged one-dimensionally along the direction AR in which the reflected light L102 is dispersed, and each light receiving element receives the separated light of each wavelength and directs the light to the processing unit 106. A signal indicating a spectrum is transmitted. Processing unit 1
At 06, the substrate 10 is subjected to predetermined correction processing and comparison with information to be referred to based on a signal from the light receiving unit 105.
The thickness of the thin film formed on the substrate 9 at the focal point SP101 is determined.

[0005]

As described above, an example of an apparatus for measuring the thickness of a thin film formed on a substrate using the spectrum of light reflected from the substrate has been described. Since only the film thickness at the light condensing point SP101 can be measured, the stage 108 on which the substrate 109 is mounted is moved in the X direction and the Y direction shown in FIG. Means are essential. Therefore, the device must be expensive and large.

Further, since the film thickness is measured while moving the stage 108, the time required to move the stage 108 lengthens the entire measurement time, making it difficult to shorten the measurement time.

Therefore, the present invention has been made in view of the above problems, and it is possible to collectively measure the film thickness of the entire substrate, thereby shortening the time for measuring the film thickness of the entire substrate and reducing the apparatus. It is an object of the present invention to provide a film thickness measuring device and a film thickness measuring method capable of achieving cost reduction and size reduction.

[0008]

According to a first aspect of the present invention, there is provided a film thickness measuring apparatus for measuring the thickness of a thin film formed on a substrate, comprising: a light source for emitting white light; And a light receiving unit comprising a plurality of light receiving elements, and an optical system for guiding light from the light source unit to the substrate, and guiding light reflected on the substrate to the light receiving unit, and only light having predetermined wavelengths different from each other. A switching unit that has a filter set including a plurality of filters that transmit light, and switches the plurality of filters on the optical path of the optical system, and a signal from the light receiving unit according to switching of the plurality of filters. And a processing unit for obtaining the thickness of the thin film based on the signal.

According to a second aspect of the present invention, in the film thickness measuring apparatus according to the first aspect, the optical system has a concave mirror for making the light from the light source unit incident on the substrate as substantially parallel light.

According to a third aspect of the present invention, there is provided a film thickness measuring device for measuring a film thickness of a thin film formed on a substrate, comprising: a light source section for emitting white light; and a light receiving means for receiving incident light. ,
An optical system that guides light from the light source unit to the substrate, and guides light reflected on the substrate to the light receiving unit,
A processing unit that obtains a signal from the light receiving unit and obtains the thickness of the thin film based on the signal, wherein the light receiving unit divides the light reflected on the substrate into a plurality of wavelength components. And a plurality of light receiving portions corresponding to each of the lights split by the splitting means. Each of the plurality of light receiving portions comprises a plurality of light receiving elements arranged two-dimensionally.

According to a fourth aspect of the present invention, a plurality of light beams having different wavelengths emitted from the light source unit are switched to irradiate a predetermined region of the reference substrate, and the light beams having different wavelengths are switched in response to the switching of the plurality of different wavelength lights. A reference information acquiring step of collectively acquiring a two-dimensional spatial distribution of the light amount of the reflected light from the reference substrate as reference information, and a plurality of different wavelengths of light emitted from the light source unit are switched to be measured. A predetermined area of the substrate on which the thin film is formed is irradiated, and a two-dimensional spatial distribution of the amount of reflected light from the substrate is collectively acquired as measurement information in accordance with switching of the plurality of different wavelengths of light. A measurement information obtaining step, a step of calculating a spectral reflection ratio of the substrate based on the reference information and the measurement information, and comparing the spectral reflection ratio with a spectral reflection ratio obtained by a theoretical calculation. And a step of determining the thickness of the thin film.

According to a fifth aspect of the present invention, there is provided the film thickness measuring method according to the fourth aspect, wherein a range determining step of determining a film thickness range which is the measurement range of the film thickness; And a wavelength setting step of setting a combination of a plurality of lights having different wavelengths emitted from the light source.

According to a sixth aspect of the present invention, there is provided the film thickness measuring method according to the fifth aspect, further comprising: a judging step of judging whether the thickness of the thin film obtained based on the reference information and the measurement information is appropriate. And a range changing step of changing the film thickness range in the range determining step according to the determination in the determining step.

According to a seventh aspect of the present invention, a predetermined region of the reference substrate is irradiated with white light from the light source unit, and a plurality of light beams having different wavelengths are divided from the reflected light from the reference substrate. Reference information obtaining step of collectively obtaining the two-dimensional spatial distribution of the light amount of the light having the wavelength as the reference information for each wavelength, and white light from the light source unit on the substrate on which the thin film to be measured is formed. A predetermined area is irradiated, light of a plurality of different wavelengths is divided from the reflected light from the substrate, and a two-dimensional spatial distribution of light amounts of the light of the plurality of different wavelengths is collectively measured for each wavelength as measurement information. Obtaining the measurement information, obtaining the spectral reflection ratio of the substrate based on the reference information and the measurement information, and comparing the spectral reflection ratio with the spectral reflection ratio obtained by theoretical calculation. By doing And a step of determining the thickness of the thin film.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

<1. First Embodiment> FIG. 1 is a view showing the structure of a film thickness measuring apparatus 1 according to a first embodiment of the present invention.

The film thickness measuring device 1 is roughly divided into a light source unit 2 that emits white light, a light L1 from the light source unit 2 guided to a substrate 91 mounted on a stage 8, and a reflected light from the substrate 91. An optical system 3 for guiding L2 to a predetermined light receiving position; a light receiving unit 5 for receiving reflected light L2 from the substrate 91;
Switching means 4 for switching a plurality of filters 43 transmitting only light of a specific wavelength out of light from the light source and arranging them on an optical path, and a thin film formed on a substrate 91 by receiving a signal from a light receiving means 5 And a processing unit 6 for calculating the film thickness.

The light source unit 2 is a light source 2 which is a halogen lamp.
1, a pinhole plate 23 having a pinhole 23h formed thereon,
The light source 21 is constituted by a lens 22 for condensing light from the light source 21 onto the pinhole 23h, and the light L1 emitted from the pinhole 23h is applied to the substrate 91 as light from a point light source.

The optical system 3 includes a lens 31 for guiding the light L1 from the light source unit 2 to the substrate 91, a half mirror 32, a diaphragm 33,
It comprises a concave mirror 34 and a lens 35 for guiding the reflected light L2 from the substrate 91 to the light receiving means 5. The light L1 from the light source unit 2 is reflected by the half mirror 32 while being condensed by the lens 31, is condensed at the position of the stop 33, is reflected by the concave mirror 34 while diverging, becomes substantially parallel light, and is substantially parallel light. Normally incident on the entire surface. The reflected light L2 from the substrate 91 again reaches the half mirror 32 via the concave mirror 34 and the stop 33,
After passing through the lens 2, an image of the irradiation area of the substrate 91, that is, an image of the entire substrate surface is formed on the light receiving means 5 via the lens 35. In the optical system 3, by using the concave mirror 34, the measurement error based on the chromatic aberration is reduced, and the measurement in the ultraviolet region is enabled.

The light receiving means 5 has a structure in which a plurality of light receiving elements are two-dimensionally arranged on a plane perpendicular to the paper surface.
Can be collectively received.

The switching unit 4 is disposed between the light source unit 2 and the optical system 3 and has a disk unit 41 having a filter and a rotation unit for rotating the disk unit 41 about an axis J in a plane perpendicular to the plane of the drawing. 42. The disk portion 41 has 30 different types of filters 43 on the same circumference centered on the axis J.
(1) to 43 (30) are provided, and when the disk portion 41 is rotated about the axis J by the rotating means 42, the filters 43 (1) to 43 (30) sequentially emit the light L1. It will be placed on the road.

The information on the image of the substrate 91 obtained by the light receiving means 5 and the information on the type of filter disposed on the optical path of the light L1 obtained from the encoder provided in the rotating means 42 are sent to the processing section 6. Here, the film thickness formed on the substrate 91 is calculated.

The configuration of this apparatus has been described above. Next, a method of acquiring information necessary for measuring the thickness of a thin film formed on the substrate 91 using this apparatus will be described. Note that the information necessary for measuring the thickness of the thin film in the apparatus 1 is two-dimensional information representing the image of the substrate 91, which is the amount of light for each wavelength of the reflected light L2 from the substrate 91. The method of obtaining the film thickness from the amount of reflected light for each wavelength, which is the obtained information, may be any method as in an example described later.

In this device, the light L emitted from the light source 2
1 is guided to the substrate 91 by the optical system 3, but since the filter 43 exists on the optical path, for example, a state in which the filter 43 (1) that transmits only the light of the wavelength λ1 is disposed on the optical path by the switching unit 4 In this case, the substrate 91 is irradiated only with the light having the wavelength λ1. Further, the disc portion 41 of the switching means 4
Are provided with filters 43 (2) to 43 (30) that transmit only light of other different wavelengths λ2 to λ30, and these filters are arranged on the optical path of the light L1 by the rotating means 42. At this time, only light having these wavelengths is irradiated on the substrate 91.

The substrate 91 is irradiated with light L1 of a specific wavelength as substantially parallel light over the entire surface, and is reflected by the substrate 91 to become reflected light L2. Light reflected on the surface or the boundary surface causes interference, and the reflected light L2 is affected by the interference.

The reflected light L2 is transmitted through the optical system 3 to the light receiving means 5
The light receiving means 5 is composed of a plurality of light receiving elements arranged two-dimensionally.
1 can collectively obtain an image of the entire substrate surface. Therefore, the state of interference in the irradiation range (in the present embodiment, the entire substrate) when the substrate 91 is irradiated with light of a specific wavelength from the light receiving unit 5 is observed.

The information indicating the two-dimensional spatial distribution of the amount of the reflected light L2 from the substrate 91 obtained by the light receiving means 5 is sent to the processing unit 6, but at the same time, the rotating means 42 A signal indicating which filter is used to obtain the information is transmitted from the encoder provided in. Therefore, the wavelength of the light applied to the substrate 91 and the two-dimensional information indicating the interference state of the irradiation range when the light of this wavelength is applied are sent to the processing unit 6. Then, the processing unit 6 collectively obtains the thickness of the thin film formed on the substrate 91 based on the information.

The method of acquiring information necessary for film thickness measurement in the apparatus 1 has been described above. When the apparatus 1 is compared with the conventional apparatus 101 shown in FIG. One point SP1 on the substrate 109
The light receiving means 105 measures the spectral spectrum of the reflected light L102 from the light receiving point SP1.
The substrate 1 is moved by moving the stage
09 is scanned to acquire the two-dimensional information of the reflected light, whereas the device 1 in this embodiment irradiates the substrate 91 with light of a specific wavelength instead of the spectral spectrum, and In that the information of the two-dimensional spatial distribution of the reflected light L2 is obtained collectively. This makes it possible to collectively acquire two-dimensional information of a predetermined region (irradiation range) of the substrate 91 without moving the substrate 91. As a result, the time required for measuring the film thickness of the entire substrate can be reduced, and the cost and size of the apparatus can be reduced.

Next, the internal processing of the processing section 6 for calculating the film thickness based on the information acquired as described above will be described together with the operation and operation of the entire apparatus. The processing unit 6 may be any method as long as it is a method of obtaining a film thickness from the amount of reflected light with respect to a plurality of specific wavelengths of light.
Here, an example of a processing method in the case where a single-layer film (single-layer film) is formed over a substrate will be briefly described.

FIGS. 2 and 3 are flowcharts showing the operation and operation of the apparatus 1 and the flow of the film thickness calculation process.

First, the operator measures the type of the thin film formed on the substrate to be measured and the thickness of the thin film and the measurement range of the film thickness (which indicates an approximate film thickness to be expected, and is hereinafter referred to as a "film thickness range"). Is specified (step S11). This is an operation for determining beforehand the measurement and shortening the measurement time because the type of filter used differs depending on the film thickness range. The initial value of the film thickness range may be determined in advance.

When the film type and the film thickness range are specified, the optical constants (reflectance N (λ), absorption coefficient K (λ), etc., which are functions of wavelength λ) of the thin film are confirmed from the specified film type. For this purpose, it is displayed on a monitor (step S12), and the spectral reflection ratio Rs (d, λ) with respect to the film thickness d and the wavelength λ is theoretically obtained using these optical constants inside the processing unit 6 (step S1).
3). As shown in FIG. 4, the spectral reflection ratio Rs (d, λ) is obtained by setting the reflectance of the substrate when the thin film is not formed to 100%.
(%), It changes almost periodically with respect to the wavelength λ, and as the film thickness increases, FIG. 4 (a) shows the case where the film thickness is the smallest, and (a), (b), Since the period has a characteristic of shortening the period (the film thickness increases in the order of (c)), the film thickness of the substrate 91 is measured using this.

Further, from the designated film thickness range, a plurality of filters (filters 43 (1) to 43 (30) provided in the disk portion 41) used for measuring the film thickness in this film thickness range are selected. And, for example, filters 43 (1) to 43 (43)
It is a combination such as (10). Hereinafter, this combination of filters is referred to as a “filter set”. ) Is selected (step S14).

Next, a substrate on which a thin film is not formed is mounted on the stage 8 in FIG. 1 as a reference substrate 92 (step S21), and a specific wavelength λf (where λf is light L1) is passed through each filter of the filter set. The reflected light L2 when the light L1 (the wavelength of the light transmitted through the filter disposed on the optical path of the light source) is irradiated is received by each of the light receiving elements i arranged two-dimensionally of the light receiving means 5 to form the film. Calibration information, which is reference information used as a reference for calculating the thickness, is obtained (step S22). That is, information B (i, λf) indicating the amount of light received by each light receiving element i and information D indicating the magnitude of the dark current of each light receiving element i used in the subsequent correction process
(i) is sent to the processing unit 6 as calibration information.

Calibration information B (i, λf), D
When (i) is obtained, the substrate 91 to be measured is placed on the stage 8 (step S31), and information S (i, λf) indicating the amount of light received by each light receiving element i is similarly obtained. It is acquired as measurement information (step S32). FIG. 5 shows typical states of the information B (i, λf) and S (i, λf) in each light receiving element (actually obtained information is discrete information using λf as a parameter. FIG. 5 shows a state with respect to a continuous wavelength change to clearly show the characteristics of each information.)

The information B (i, λ) thus obtained
f), S (i, λf), and D (i), the substrate 9 connected to each light receiving element i in the processing unit 6 using the equation shown in Equation 1.
A spectral reflection ratio T (i, λf) at a position corresponding to one image is obtained (step S41). This spectral reflection ratio T (i, λ
FIG. 6 shows a typical state of f) (actually obtained information is discrete information, but is shown continuously as in FIG. 5).

[0036]

(Equation 1)

Next, from the spectral reflection ratio T (i, λf), a temporary film thickness da (i), which is an approximate film thickness at the position of the substrate 91 corresponding to the light receiving element i, is obtained by the equation shown in Expression (2). Step S42). In this equation, λ1, λ2
Is a wavelength indicating an approximate extreme value of the spectral reflection ratio as shown in FIG. 6, and the refractive indexes of the thin film at this time are n1 and n2. Further, the number of extreme values existing between these wavelengths is X
It is.

[0038]

(Equation 2)

When the provisional film thickness da (i) is obtained, the vicinity ((da (i) -α) to (da (i) + α)) of this film thickness is obtained by a theoretical calculation for the film thickness d as a film thickness inspection range. Spectral reflection ratio Rs (d, λ) and spectral reflection ratio T obtained by actual measurement
Based on (i, λf), the accurate film thickness d at the position of the substrate 91 corresponding to the light receiving element i using the curve fitting method
Calculate t (i). That is, as shown in FIG. 7, the relationship between the sum of squared errors Es (i, d) obtained from the equation shown in Expression 3 and the film thickness d is plotted as points, and these points are interpolated to sum up the sum of squared errors Es ( The film thickness dt (i) that minimizes i, d) is obtained.

[0040]

(Equation 3)

The error sum of squares Es (i, dt) at this time is
Is compared as a GOF (Good of Fitness) value for judging whether or not the obtained film thickness dt (i) is an appropriate value. It is determined that the film thickness dt (i) is an appropriate value (steps S43 to S46). If the GOF determination result indicates that the value of the measured film thickness is appropriate, the film thickness dt (i), the GOF value, and the GOF determination result are displayed on a monitor (step S47).

Here, if the GOF determination result is that the measured film thickness is not an appropriate value, step S
Specified in 11 (or predetermined)
The thickness range is changed to another thickness measurement range, and the measurement process is started again. In this case, the process of acquiring the reference information and the measurement information is omitted. Thus, the measurement process is repeated until the GOF determination result indicates that the measurement value is an appropriate thickness measurement value, or until the measurement in the entire thickness range is completed.

By making such a change in the film thickness range, for example, when the designated (or predetermined in the initial state) film thickness range is inappropriate or when the film thickness is unknown. Also, appropriate film thickness measurement becomes possible.

As described above, as an example of the operation and operation of the film thickness measuring apparatus 1 in this embodiment and the film thickness calculation processing,
Although the case where the single-layer film is formed on the substrate 91 has been described, it is needless to say that the present invention is not limited to this method, and that the film thickness can be obtained from the relationship between the wavelength of reflected light and the amount of light. If so, any method may be used.

For example, the spectral reflection ratio T of a very thin thin film
If (i, λf) is given for two different wavelengths,
As shown in FIG. 4, since the period of the periodic change with respect to the wavelength of the spectral reflection ratio becomes longer, the film thickness can be obtained from the change amount of the spectral reflection ratio with respect to the wavelength obtained from these two values. Therefore, when at least two filters are present, it is possible to measure the thickness of a very thin thin film.

The present invention is not limited to a single-layer film, and can be used even when a plurality of laminated thin films (multilayer films) are formed on the substrate 91. In this case, a substrate on which a thin film is not formed or a substrate on which a completely opaque film (a film that absorbs light in the layer and does not transmit light in the lower layer) is used as the reference substrate 92 in the above process. The processing performed by the processing unit 6 also uses a method for calculating the thickness of the multilayer film.

<2. Second Embodiment> FIG. 8 is a view showing a light receiving means 5a of a film thickness measuring apparatus according to a second embodiment of the present invention. This device is the same as the device 1 of the first embodiment shown in FIG. 1 except that there is no switching means 4 and only the light receiving means 5 is different. That is, the apparatus in this embodiment is one in which all the switching means 4 are removed from the apparatus 1 shown in FIG. 1 and the light receiving means 5 is configured as shown in FIG. Therefore, the white light from the light source unit is incident on the substrate without passing through the filter, and the reflected light is received by the light receiving unit 5a.

The light receiving means 5a includes a lens 51 for converting the reflected light L2 into substantially parallel light, and four dichroic mirrors 52a to 52d for reflecting light L2a to L2d having specific wavelengths among the light transmitted through the lens 51. Light L2a to L2
It is composed of lenses 53a to 53d for condensing d, and light receiving units 54a to 54d which are composed of light receiving elements arranged two-dimensionally and receive these lights.

With such a configuration, the light L2 incident on the light receiving means 5a is divided by the dichroic mirror 5
The light is divided into light L2a to L2d having a specific wavelength by 2a to 52d and received two-dimensionally in the light receiving units 54a to 54d. As in the first embodiment, two-dimensional light is reflected from the substrate for each wavelength. The information on the spatial distribution is obtained. The information obtained in this way is transmitted to the light receiving units 54a to 54a.
From step d, the film is sent to the processing unit, and the same processing as in the first embodiment is performed, so that the thickness of the thin film formed on the substrate can be obtained all over the substrate.

As described above, also in the second embodiment, it is possible to measure the amount of reflected light of each wavelength of the entire substrate without moving the substrate, and as a result, to measure the film thickness of the entire substrate. It is possible to shorten the time, reduce the price of the device, and reduce the size.

<3. Modifications> Although the film thickness measuring apparatus according to the present invention and the film thickness measuring method in this apparatus have been described according to the embodiments, the present invention is not limited to the above embodiments.

For example, in the first embodiment and the second embodiment referring to FIG. 1, the concave mirror 34 is used for the optical system 3, but the light L1 incident on the substrate 91 and the substrate 9
Any light may be used as long as the light L2 reflected from the light source 1 can be appropriately guided. FIG. 9 is a diagram showing an example in which the light L1 is guided to the substrate 91 using the lens 34a, and the light L2 from the substrate 91 is guided to the light receiving unit 5.

In the first embodiment, the filter 43
The light receiving means 5 receives light of a specific wavelength by using (1) to 43 (30). In the second embodiment, light L2a to L2a of specific wavelength is used by using dichroic mirrors 52a to 52d. L2d is received by the light receiving units 54a to 54d, but the number of these filters and dichroic mirrors is not limited to this, and may be two or more. Further, the switching means 4 in the first embodiment may be of any type as long as it can switch the filter. Instead of switching the filter by the rotating means 42, for example, The filter may be switched in a sliding manner. Also in the second embodiment, the dichroic mirrors 52a to 52d functioning as a splitting unit may be of any form as long as the light is split for each wavelength. For example, after splitting by a half mirror, You may let it pass.

Further, the thin film formed on the substrate is not limited to a single-layer film, and the processing inside the processing unit 6 may be a method in which the film thickness is determined from the relationship between the wavelength of the reflected light L2 from the substrate 91 and the amount of light. Any processing content may be used as described in the first embodiment.

In the first embodiment, a halogen lamp is used as the white light source 21, but a xenon lamp may be used. In addition, although the substrate 91 is irradiated with light of a specific wavelength by passing white light through a filter, the substrate 91 is irradiated with light of a plurality of different wavelengths using a plurality of LEDs or lasers without using a filter. It is also possible to use it.

In the first embodiment, the switching means 4 is disposed between the light source unit 2 and the optical system 3, but may be disposed anywhere on the optical path of the light L1 or L2.

Further, in the above embodiment, the light L1 from the light source unit 2 is applied to almost the entire surface of the substrate 91. However, if it is not necessary to measure the film thickness of the entire surface of the substrate 91, Light may be applied to only a part of 91.

[0058]

According to the first aspect of the present invention, a filter that transmits only light of a predetermined wavelength is disposed on the optical path of the optical system by switching, so that light of a predetermined wavelength can be applied to the substrate. In addition, since the light reflected from the substrate is collectively received by the light receiving elements arranged two-dimensionally, the amount of reflected light from a predetermined region of the substrate can be acquired collectively. This makes it possible to collectively obtain the film thickness of a predetermined region of the substrate, and it becomes unnecessary to move the substrate.
The measurement time can be shortened, and the price and size of the device can be reduced.

According to the second aspect of the present invention, since the concave mirror is used in the optical system, in addition to the effect of the first aspect, a measurement error based on chromatic aberration can be reduced and a measurement in an ultraviolet region can be performed. be able to.

According to the third aspect of the present invention, the reflected light from the substrate is divided into lights for each wavelength, and each light is
Since the light is received by the light receiving unit including the light receiving elements arranged in a dimension, the amount of light of each wavelength of the reflected light in a predetermined area of the substrate can be acquired at a time. This makes it possible to collectively determine the film thickness in a predetermined region of the substrate. As a result, a means for moving the substrate becomes unnecessary, so that the measurement time can be shortened, and the apparatus can be reduced in cost and size.

According to the fourth aspect of the present invention, the substrate is illuminated by switching light of different wavelengths, and the two-dimensional spatial distribution of the amount of light reflected from the substrate is obtained collectively. The film thickness can be obtained collectively. Thus, the measurement time can be reduced, and the cost and size of the apparatus for measuring the film thickness can be reduced.

According to the fifth aspect of the present invention, the thickness range of the film thickness to be measured is determined, and the combination of the wavelengths of the light irradiated on the substrate is set from the thickness range. Is irradiated on the substrate, so that the film thickness can be quickly measured.

According to the sixth aspect of the present invention, the appropriateness of the obtained film thickness is determined, and the setting of the film thickness range is changed in accordance with the determination result. Even if the setting is inappropriate, accurate film thickness measurement can be performed.

In the invention according to claim 7, light of a plurality of different wavelengths is divided from the reflected light from the substrate, and the two-dimensional spatial distribution of these lights is obtained collectively for each wavelength. Can be collectively determined for the predetermined region. Thus, the measurement time can be reduced, and the cost and size of the apparatus for measuring the film thickness can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a film thickness measuring device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a flow of operation and processing of a film thickness measuring device.

FIG. 3 is a diagram showing an operation and a processing flow of a film thickness measuring apparatus.

FIG. 4 is a diagram illustrating an example of a relationship between a wavelength and a theoretically calculated value of a spectral reflection ratio.

FIG. 5 is a diagram illustrating an example of a relationship between a wavelength and an output of a light receiving element.

FIG. 6 is a diagram illustrating an example of a relationship between a wavelength and a spectral reflection ratio.

FIG. 7 is a diagram illustrating an example of a relationship between a film thickness and a sum of error squares.

FIG. 8 is a diagram showing a configuration of a light receiving unit of a film thickness measuring device according to a second embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of a film thickness measuring apparatus according to another embodiment of the present invention.

FIG. 10 is a diagram showing a configuration of a conventional film thickness measuring device.

[Explanation of symbols]

 Reference Signs List 1 film thickness measuring device 2 light source unit 3 optical system 4 switching unit 5 light receiving unit 5a light receiving unit 6 processing unit 34 concave mirror 42 rotating unit 43 filter 52a to 52d dichroic mirror 54a to 54d light receiving unit 91 substrate 92 reference substrate L1 light L2 reflected light L2a Reflected light S11 to S47 Step

Claims (7)

[Claims] 1. A film thickness measuring device for measuring a film thickness of a thin film formed on a substrate, comprising: a light source section for emitting white light; and a light receiving means comprising a plurality of light receiving elements arranged two-dimensionally. An optical system that guides light from the light source unit to the substrate and guides light reflected on the substrate to the light receiving unit; and a filter set including a plurality of filters that respectively transmit only light having predetermined different wavelengths. Switching means for switching and arranging the plurality of filters on the optical path of the optical system, acquiring a signal from the light receiving means in response to switching of the plurality of filters, and forming the thin film based on the signal. A film thickness measuring device comprising: 2. The film thickness measuring apparatus according to claim 1, wherein the optical system has a concave mirror for making the light from the light source unit incident on the substrate as substantially parallel light. measuring device. 3. A film thickness measuring device for measuring a film thickness of a thin film formed on a substrate, comprising: a light source unit for emitting white light; a light receiving unit for receiving incident light; An optical system that guides the light to the substrate, and guides the light reflected by the substrate to the light receiving unit, a processing unit that acquires a signal from the light receiving unit, and obtains a film thickness of the thin film based on the signal. Wherein the light receiving unit has: a dividing unit that divides the light reflected on the substrate into a plurality of wavelength components; and a plurality of light receiving units corresponding to each of the lights divided by the dividing unit. A film thickness measuring apparatus, wherein each of the plurality of light receiving sections is composed of a plurality of light receiving elements arranged two-dimensionally. 4. A plurality of light beams of different wavelengths emitted from a light source unit are switched to irradiate a predetermined area of a reference substrate, and reflected from the reference substrate according to the switching of the plurality of different wavelength light beams. A reference information acquisition step of collectively acquiring a two-dimensional spatial distribution of light quantity of light as reference information, and a thin film to be measured is formed by switching light of a plurality of different wavelengths emitted from the light source unit. Irradiating a predetermined area of the substrate, a measurement information obtaining step of collectively obtaining a two-dimensional spatial distribution of the amount of reflected light from the substrate as measurement information in accordance with switching of the plurality of different wavelengths; Calculating the spectral reflection ratio of the substrate based on the reference information and the measurement information; and comparing the spectral reflection ratio with the spectral reflection ratio obtained by theoretical calculation to obtain a film thickness of the thin film. A film thickness measuring method comprising: 5. The film thickness measuring method according to claim 4, wherein: a range determining step of determining a film thickness range that is the film thickness measuring range; and a plurality of light emitted from the light source unit from the film thickness range. A wavelength setting step of setting a combination of lights having different wavelengths. 6. The method of measuring a film thickness according to claim 5, wherein: a determining step of determining whether the thickness of the thin film obtained based on the reference information and the measuring information is appropriate; A range changing step of changing the film thickness range in the range determining step according to the determination. 7. A method for irradiating a predetermined area of a reference substrate with white light from a light source unit, splitting a plurality of light beams having different wavelengths from light reflected from the reference substrate, and A reference information acquisition step of collectively acquiring a two-dimensional spatial distribution of light amount as reference information for each wavelength, and irradiating a predetermined region of a substrate on which a thin film to be measured is formed with white light from the light source unit Measuring a plurality of different wavelengths of light from the reflected light from the substrate, and collectively obtaining a two-dimensional spatial distribution of the light amounts of the plurality of different wavelengths as measurement information for each wavelength; An information acquisition step, a step of calculating a spectral reflection ratio of the substrate based on the reference information and the measurement information, and comparing the spectral reflection ratio with a spectral reflection ratio obtained by theoretical calculation, Calculate thin film thickness And measuring the film thickness.