JP2821585B2 - In-plane distribution measuring method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention provides a display using liquid crystal, magnetic file, in the material or element obtained by laminating a thin film on a substrate in the field of semiconductor, the in-plane distribution of the physical quantity related to these materials and elements non The present invention relates to an in-plane distribution measuring method and apparatus suitable for destructive and quick measurement.

[0002]

2. Description of the Related Art In many fields such as semiconductors, materials and elements in which a number of thin films are laminated on a substrate are used. Since the characteristics of the formed film affect the function of the material and the element, it is necessary to control it well, and for that purpose, accurate measurement of physical quantity indicating film characteristics and distribution measurement in the film plane are essential It is. For this reason, several methods for measuring film properties using electromagnetic waves of various wavelengths have been devised. As an example, a method for measuring film properties using X-rays as electromagnetic waves will be described below.

FIG. 2 shows an outline of a conventional measuring method. The X-ray 3 from the X-ray source 1 is appropriately shaped by the slit 2 and then irradiated onto the sample 4. The intensity of the X-rays 5 reflected from the sample 4 is measured by the X-ray detector 6 as a function of the oblique angle θ of the X-rays to the sample. The reflected X-ray profile is measured by rotationally scanning the position of the sample and the detector while maintaining the relationship of θ / 2θ. FIG. 3 shows a schematic diagram of a reflection profile when there is one film on the sample substrate. A vibration pattern is generated in an angle region slightly larger than the total reflection angle θc determined by the wavelength of the X-ray and the substance of the substrate or the film. From this reflection profile, physical quantities such as film thickness, film refractive index, film density, film surface or roughness between the film and the substrate can be determined. These physical quantities indicate the average value of the region irradiated with X-rays. On the other hand, in measuring the in-plane distribution of these physical quantities, the sample is appropriately translated and scanned, and the reflection profile is measured at each desired measurement position to obtain the distribution of the entire sample.

Japanese Patent Application Laid- Open No. Hei 5-322804 discloses an apparatus for measuring a physical quantity in an irradiation area of divided X-rays from a reflection profile divided in a wide direction of the sheet using a sheet-like X-ray flux. Have been.

[0005]

The in-plane distribution of the characteristics of the film laminated on the substrate is useful information for improving the characteristics of materials and elements, improving the film forming process, controlling the quality, and decreasing the yield. Furthermore, with the development of microfabrication technology and film deposition technology, many devices can be formed on a substrate. Therefore, there is a need to quickly and nondestructively measure the in-plane distribution of film characteristics with high positional resolution. There is. However, the conventional apparatus has the following problems.

Since the measured physical quantity is an average value of the area irradiated with the electromagnetic wave, there is a problem that it is difficult to measure the physical quantity in an area smaller than the area irradiated with the electromagnetic wave. Further, when the irradiation area of the electromagnetic wave to the sample is limited to be small in order to increase the resolution of the in-plane distribution, there is a problem that the use efficiency of the electromagnetic wave is reduced and an enormous measurement time is required. Further, even when the physical quantity is measured by dividing the electromagnetic wave on the sheet, there is a problem that it is difficult to measure in a region smaller than the irradiation region of the divided electromagnetic wave.

[0007] It is an object of the present invention to provide a method for measuring the surface of a sample
It is an object of the present invention to provide a method and an apparatus for non-destructively measuring the in-plane distribution of physical quantities at high resolution .

[0008]

According to the present invention, there is provided a method for measuring in-plane distribution according to the present invention, wherein electromagnetic waves are incident on a sample from a number of directions whose relative positions are specified. Measuring a large number of reflected electromagnetic waves reflected from the sample in response to a large number of incident electromagnetic waves in series by the detecting means, data based on the mutual positional relationship between the large number of reflected electromagnetic waves detected by the detecting means and the incident electromagnetic waves The in-plane distribution of the physical quantity of the sample is obtained by calculating the physical quantity of the sample corresponding to an area smaller than the irradiation area of the electromagnetic wave by arithmetic analysis processing, and obtaining the physical quantity for each of the small areas over the entire area to be measured of the sample. It is characterized by the following.

Further, by irradiating the sample with electromagnetic waves, a large number of electromagnetic waves emitted from the sample in a number of directions are measured in series together with their mutual positional relationship by detecting means, and a large number of electromagnetic waves detected by the detecting means are measured. Obtaining the physical quantity of the sample corresponding to an area smaller than the irradiation area of the electromagnetic wave by data arithmetic analysis processing based on the emitted electromagnetic waves and their mutual positional relationship, and obtaining the physical quantity for each of the small areas over the entire measurement area of the sample. The in-plane distribution measuring method is characterized in that the in-plane distribution of the physical quantity of the sample is obtained by the following method.

Further, the in-plane distribution measuring apparatus of the present invention for realizing the above-mentioned method of the present invention comprises: a sample holding means for holding a sample;
An electromagnetic wave generation source that causes an electromagnetic wave to be incident on the sample; a detecting unit that detects a reflected electromagnetic wave reflected from the sample in response to the incident electromagnetic wave; and specifying a mutual positional relationship of an incident direction of the incident electromagnetic wave to the sample. And a position changing mechanism that changes the position of the electromagnetic wave by a data calculation analysis process based on a series of a large number of reflected electromagnetic waves detected by the detection means corresponding to each incident direction of the incident electromagnetic wave and the mutual positional relationship of the incident electromagnetic wave. An in-plane distribution calculation processing means for obtaining a physical quantity of the sample corresponding to an area smaller than the irradiation area, and obtaining the in-plane distribution of the physical quantity of the sample by obtaining the physical quantity for each of the small areas over the entire area to be measured of the sample. It is characterized by having.

A sample holding means for holding the sample; an electromagnetic wave source for irradiating the sample with electromagnetic waves; a detecting means for detecting an emitted electromagnetic wave emitted from the sample in response to the irradiated electromagnetic waves; A position changing mechanism for changing the relative position of the detecting means and the mutual positional relationship while specifying the mutual positional relationship, and a series of multiple reflected electromagnetic waves detected for each of the positions by the detecting means and data based on the mutual positional relationship. The in-plane distribution of the physical quantity of the sample is obtained by calculating the physical quantity of the sample corresponding to an area smaller than the irradiation area of the electromagnetic wave by arithmetic analysis processing, and obtaining the physical quantity for each of the small areas over the entire area to be measured of the sample. An in-plane distribution measuring device comprising an in-plane distribution calculation processing means.

In the above-described in-plane distribution measuring apparatus, the position changing mechanism is characterized in that the sample holding means is formed by a mechanism for rotating the sample around a normal direction of a surface of interest of the sample. Or a mechanism formed by a mechanism for rotating the electromagnetic wave generation source and the electromagnetic wave detection means around the normal direction of the surface of interest of the sample. Here, the sample holding means preferably has a mechanism for moving the sample in a direction orthogonal to the traveling direction of the electromagnetic wave emitted from the electromagnetic wave generation source. Alternatively, it is preferable that the electromagnetic wave generation source and / or the electromagnetic wave detection unit include a mechanism that moves in a direction orthogonal to a normal direction of a surface of interest of the sample.

In the above-mentioned in-plane distribution measuring apparatus, the electromagnetic wave detecting means uses an electromagnetic wave detector for detecting an electromagnetic wave through a slit, and limits an area where the electromagnetic wave is generated from the sample. Is good. The electromagnetic wave detecting means may be a one-dimensional position-sensitive detector or a two-dimensional position-sensitive detector. The detecting means preferably has a mechanism for changing the position resolution. Further, it is preferable that a mechanism is provided between the electromagnetic wave generation source and the sample, which has a mechanism for expanding the width of the electromagnetic wave emitted from the electromagnetic wave generation source. Further, it is preferable that a mechanism is provided between the electromagnetic wave generation source and the detection means, for limiting the wavelength of the electromagnetic wave emitted from the electromagnetic wave generation source or for scanning the wavelength.

[0014]

According to the present invention, the above object is achieved by the following operations. First, the configuration of the in-plane distribution measuring apparatus according to the present invention is shown in FIG. 1 and the operation of the present invention will be described. The electromagnetic wave 3 emitted from the electromagnetic wave source 1 is formed by the slit 2 and then enters the sample 4 at a viewing angle θ. A one-dimensional position-sensitive electromagnetic wave detector 6 detects the electromagnetic wave 5 reflected by the sample.
Measure with By an appropriate data analysis process based on the measured intensity or wavelength of the electromagnetic wave 5, an average physical quantity of a region on the sample corresponding to the electromagnetic wave 5 incident on one element of the one-dimensional position sensitive detector can be obtained. For example, a reflected X-ray profile using X-rays as an electromagnetic wave and the viewing angle θ as a variable (FIG. 3)
From the sample irradiation area, the refractive index n,
Physical quantities such as density ρ and roughness σ are obtained. This will be described with reference to FIG. 4 in the case where there is one film on the sample substrate. In FIG. 4, n ₁ , n ₂ and n ₃ are the refractive indexes of air, the thin film and the substrate.

The X-ray reflection intensity R when X-rays having a wavelength λ is incident on a sample is expressed by J. H. Underwood (J.
H. Underwood) and tea. W. Barbie (T.
W. Barbee) AIP Conference Proceedings, Law Energy X-Ray Diagnostics-1981, American Institute of Physics, New York 1981 (AIP Conferenc
e Proceeding, Low Energy X-ray Diagonostics-1
981, American Institute of Physics, New York 1
981) and bee. Baidaru (B.Vidal) and copy. Vincent (P.Vivcent) (Appl.O p t.23 Vol. 1794, pp. 1984
The following is the calculation based on the formula described in (Year). Here, d is the film thickness, and σ ₁ and σ ₂ are the roughness of the interface between the air and the film and the interface between the film and the substrate, respectively.

[0016]

(Equation 1)

Further, δ ₂ and δ ₃ represent the amounts of deviation of the real part of the refractive index n from 1 in the film and the substrate, and are given by the following equations.
Here, r _e is the classical electron radius, N ₀ is Avogadro's number, Z is the atomic number, A is the atomic weight, [rho is the density.

[0018]

(Equation 2)

In the equation (Equation 1), the contribution of the imaginary part β of the refractive index to R is neglected, and the approximation R≪1 is used. From equation (1), it can be seen that R is a function of d, δ, and σ with respect to θ. In particular, the oscillation of the X-ray reflection intensity at an angle larger than θc in FIG. 3 depends on the cos components d ₂ and δ ₂ of the third term of the equation (1) of the equation (Equation 1). From the above, physical quantities such as the film thickness d, the roughness σ, and δ can be obtained from the measured X-ray reflection intensity R by using the equation (Equation 1). Further, the density ρ of the film can be obtained from the equation (Equation 2). The above is the method of obtaining the physical quantity by the conventional method. However, the obtained physical quantity is that of a wide region irradiated with X-rays (a region that extends long in the X-ray incident direction because the X-ray incident angle is small). Therefore, considering the physical quantity obtained above as an average value in the X-ray irradiation area,
The point of the present invention is to obtain the in-plane distribution of the physical quantity at a resolution much smaller than the utilization area of the sample irradiation of X-rays by using a conventionally used computer tomography (CT) technique. Next, the measurement method and the method of obtaining the measurement will be described.

According to the above-described procedure, a physical quantity in an irradiation area with X-rays can be obtained. Next, the sample is rotated by a predetermined angle around the normal direction of the surface of interest of the sample as a central axis, and the physical quantity of the sample is obtained from the same measurement. This is the rotation of the sample
Repeat until 180 or 360 degrees. From these series of measurements, an in-plane distribution of the physical quantity can be obtained by an analysis process described below.

FIG. 5 shows a principle diagram for obtaining the in-plane distribution.
Let d (x, y) be the in-plane distribution of the physical quantity of interest,
The angle between the coordinate system x′-y ′ fixed to the laboratory and the coordinate system xy fixed to the sample is defined as φ. In the above measurement, the angle φ of the sample, the position x ′ of the one-dimensional position-sensitive detector
The physical quantity D (x ′, φ) obtained from the measurement of the element of
Since it is the average value in the irradiation area of the line, it is expressed by the following equation.

[0022]

(Equation 3)

Next, P (x ', φ) shown by the following equation (Equation 4)
Thus, Equation (Equation 3) becomes the following Equation (Equation 5).

[0024]

(Equation 4)

[0025]

(Equation 5)

From the equation (5), d (x, y) can be obtained by using a general computer tomography (CT) algorithm. Hereinafter, only the results of the filter back projection method used in general CT are shown.

[0027]

(Equation 6)

By using equations (4) to (6),
From the physical quantity D (x ′, φ) obtained by the measurement, d (x,
y) can be determined. D (x, y) obtained
Is a small area of 1 / (N · M) of the X-ray irradiation area shown in FIG. 1, where N is the number of times the sample is rotated and M is the number of elements of the one-dimensional position sensitive detector. is there. With the above-described measurement and analysis methods, it is possible to non-destructively measure the in-plane distribution of physical quantities with a resolution of a region much smaller than the irradiation region of the electromagnetic wave.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.
FIG. 1 shows a configuration diagram of an in-plane distribution measuring apparatus according to one embodiment to which the present invention is applied. In the present embodiment, X-rays were used as electromagnetic waves. As shown in the figure, an X-ray 3 emitted from an X-ray source 1 is shaped by a slit 2 and then a sample 4
Incident on. The X-ray 5 reflected by the sample 4 is measured by the X-ray detector 6.

As the X-ray source 1, an ordinary X-ray tube using Cu as a target was used. As the slit 2, a solar slit that suppresses angular divergence of X-rays in the x ′ and z ′ directions was used. X-ray passing through the slit 2 is 10 mm in the x 'direction, 0.1 mm in the z' direction, and the angular divergence is several mrad.
Limited to a degree. By inserting a Ni filter between the X-ray source 1 and the slit 2, Cu-Kβ rays are suppressed, and quasi-monochromatic light by Cu-Kα rays is realized. The disk-shaped sample 4 is fixed on a sample holder 7.
The sample holder 7 is provided with a translation mechanism in the x ′, y ′, z ′ directions and a rotation mechanism about the x ′, y ′, z ′ axes, so that the position of the sample 4 can be adjusted. Has become. As the X-ray detector 6, an X-ray imaging tube which is a two-dimensional position sensitive detector was used. The X-ray imaging tube is fixed on the detector base 8. The detector base 8 is provided with a translation mechanism in the x ′, y ′, z ′ directions and a rotation mechanism about the x ′ axis, so that the position of the sample 4 can be adjusted. The control unit 9 controls the detector 6, the sample holding table 7, and the detector table 8. The control unit 9 includes a driver for a driving mechanism of the sample holding table 7 and the detector table 8, a driver controller, a controller of an X-ray imaging tube, a detected image processing unit, a computer, and the like.

Next, a method for measuring the in-plane distribution of the physical quantity in the sample using the apparatus of the embodiment configured as described above will be described. The sample has a thickness of about 1 deposited on a Si substrate.
It is a Ni film of 00 °, and its in-plane distribution is obtained according to the present invention from the film thickness, refractive index, and roughness according to the X-ray reflection profile.

The detector base 8 is adjusted so that the X-ray 3 passing through the slit 2 can be directly detected by the X-ray imaging tube, and the distance between the sample and the X-ray imaging tube is R. Next, the sample holder 7 is adjusted so that the rotation axis around the x 'axis of the sample 4 coincides with the sample surface. Similarly, adjustment is performed so that the X-ray 3 and the surface of the sample 4 are parallel to each other, and the center of the width of the X-ray 3 in the x ′ direction coincides with the rotation center of the sample 4 around the z ′ axis. After the completion of the adjustment, the sample 4 is rotated by the initial angle θ1 (0.1 degrees in this embodiment) about the x ′ axis as the rotation center. The intensity I (x ′, z ′) of the X-ray 5 reflected by the sample 4 is detected by the X-ray imaging tube. The intensity in the z ′ direction is a function of the oblique angle θ of the X-ray 3 with respect to the sample 4, and has a relation of z ′ = Rtan2θ. From this, it is possible to convert the detection position z 'of the X-ray imaging tube into the viewing angle θ. Next, the sample 4 is rotated by a small angle δθ to measure the reflected X-ray intensity. This scanning is repeated up to a preset angle θ2 (1.2 degrees in the present embodiment), and this series of operations is repeated by changing x ′, thereby obtaining each x ′ as shown in FIG. The reflected X-ray profile can be obtained. The thickness, refractive index, density, and roughness of the Ni film on the sample can be obtained from this profile, the expression of Fresnel for X-ray reflection, and the simulation in the case where the reflection surface is multi-layered. Taking the film thickness d as an example of the physical quantity to be focused on now, d (x ′) can be obtained from the reflection X-ray profile.

Next, the sample 4 is set at a small angle δφ around the z ′ axis.
(0.5 degrees in the present embodiment), and d (x ′, δφ) is obtained from the same measurement. This scanning is repeated until the rotation angle of the sample 4 becomes 180 degrees. From these series of measurements, d (x ′, φ) is obtained. Finally, d (x ',
From the data group of (φ), the in-plane distribution of the film thickness d (x, y) of the Ni film can be obtained by using the computer tomography algorithm (the filter back projection method in this embodiment) described in the section of the operation. . This is performed by a computer in the control unit 9 of FIG.

In this embodiment, the position resolution of the X-ray imaging tube in the x 'direction was set to 20 μm, and 512 points were measured in the x' direction. The number of rotations of the sample 4 with respect to the z ′ axis is 360 points. From now on, the resolution of the in-plane distribution in the sample is about 20 μm
This indicates that the measurement can be performed with a much smaller resolution and nondestructively than the irradiation area of the sample of 10 mm × 10 mm.

In the present embodiment, it is possible to use a generally used algorithm for computer tomography or a hardware processor dedicated to fast Fourier transform, so that the calculation of the in-plane distribution of physical quantities can be speeded up. There is.

In this embodiment, since the X-ray image pickup tube, which is a two-dimensional position sensitive detector, is used as the X-ray detector 6, the profile in the x 'direction can be simultaneously measured when measuring the reflected X-ray profile. At the same time, it is not necessary to move the detector 6 in accordance with the scanning of the oblique angle θ, so that there is an effect that the profile measurement becomes easy. The X-ray image pickup tube can measure an X-ray image by reading and finding two-dimensionally an electron-hole pair generated on an X-ray photosensitive surface by an incident X-ray by an electron beam from an electron gun. I have. With this structure, the scanning range of the read-out electron beam can be arbitrarily changed, so that the positional resolution of the read-out X-ray image can be easily changed according to the measurement. This has the effect that the positional resolution of the in-plane distribution of the physical quantity of interest on the sample surface can be easily changed according to the size of the sample. That is, the X-ray detector 6
In addition, by providing a mechanism for changing the detection position resolution, the above-described effect can be obtained.

In this embodiment, by using a solar slit as the slit 2, the divergence angle of the X-ray 3 is suppressed, and the reflection X-ray profile can be measured with high accuracy.

In this embodiment, the mechanism for rotating the sample 4 is adopted as the mechanism for causing the X-rays 3 to enter the sample 4 from many directions, so that the structure of the sample holder 7 is simplified.
There is an effect that the entire measuring device can be reduced in size.

Next, some modifications of the embodiment of FIG. 1 will be described. First, a photodiode array (PDA) which is a one-dimensional position-sensitive detector can be used as the X-ray detector 6 instead of the embodiment of FIG. By using an X-ray-visible light fluorescent film for the entrance window of the PDA, it can be used as the X-ray detector 6. In this case, in measuring the reflected X-ray profile, it is necessary to drive the position z ′ of the detector 6 in synchronization with the scanning of the sample at the oblique angle θ while maintaining the relationship z ′ = Rtan2θ. Other measurement procedures are the same as those in the embodiment of FIG. 1, and the in-plane distribution of the physical quantity of interest in the sample can be measured. In this modification, the use of a one-dimensional detector as the X-ray detector 6 has the effect of simplifying the signal processing system from the detector. Further, since the reflected X-ray profile in the x 'direction can be simultaneously measured by employing the one-dimensional detector, there is an effect that the measurement time can be reduced.

Next, a scintillation counter having no position detecting function can be used as the X-ray detector 6 instead of the embodiment shown in FIG. In this case, the configuration of the device is, for example, as shown in FIG. In the reflection X-ray profile measurement in this embodiment, it is necessary to scan the sample 4 in the x ′ direction in addition to the scanning in the z ′ direction of the X-ray detector described above.
By these scans, the physical quantity of interest of the sample is obtained as a function of x ′ and φ, and the subsequent measurement procedure is the same as the embodiment of FIG. In this modification, the use of a very simple detector as the detector 6 has an effect that the signal processing system from the detector 6 becomes very simple. Further, in this modification, since the X-ray 3 which is a very narrow beam by the slit 2 can be used, there is an effect that the in-plane distribution of the physical quantity of interest on the sample can be measured with a high resolution of several μm.

Next, instead of the embodiment shown in FIG. 1, an X-ray source capable of emitting X-rays of high intensity and continuous wavelength is used as the X-ray source 1, and an X-ray source is provided between the X-ray source 1 and the sample 4. A crystal spectrograph capable of scanning the wavelength of the line 3 can be provided. As the crystal spectrometer, a channel cut spectrometer of Si (111) was used.
By driving the spectroscope in translation during wavelength scanning, the emission position of the X-rays 3 emitted from the spectroscope can be kept constant. In this case, the measurement of the reflected X-ray profile
This is a measurement of the reflected X-ray intensity with respect to the X-ray wavelength. From the reflection X-ray profile with respect to the X-ray wavelength, physical quantities such as the film thickness, the refractive index, the density, and the roughness of the film on the sample can be obtained from the same simulation as in the embodiment of FIG. In the present embodiment, the scanning of the X-ray wavelength for the measurement of the reflected X-ray profile eliminates the need for the X-ray detector 6 to perform the driving scan for the viewing angle θ of the sample, and the structure of the detector base 8 is reduced. This has the effect of being simple. Further, in this embodiment, by scanning in the wavelength range including the X-ray absorption edge wavelength of the element of interest, there is an effect that information on only a specific element of the film on the sample can be obtained.

In place of the embodiment shown in FIG. 1, an asymmetrical reflection crystal is provided between the X-ray source 1 and the sample 4 to increase the width of the X-rays 3 emitted from the X-ray source 1 in the x 'direction. it can. According to the present invention, the in-plane distribution can be measured with high efficiency if the width of the X-ray incident on the sample 4 is substantially equal to the diameter of the sample. When the diameter of the sample is much larger than the width of the X-rays emitted from the X-ray source 1, the enlargement of the X-ray width according to the present embodiment is effective. FIG. 6 shows a principle diagram for expanding the X-ray width by the asymmetric reflection crystal. As an asymmetric reflection crystal, Si (1
The channel cut crystal of 11) was used. The crystal is cut out so that the surfaces of the first crystal and the second crystal are non-parallel as shown in FIG. 6, and the lattice planes of the first crystal and the second crystal that reflect the X-rays are parallel, and The two crystals are asymmetric reflection crystals. X-ray 3 incident on the channel cut crystal
After diffracted by the first and second crystals, the separated X-rays are emitted from the channel cut crystal. At this time, the second
Since the incident angle and the outgoing angle of the X-ray with respect to the crystal are different, the width Wou of the X-ray emitted from the channel cut crystal is
t is enlarged as compared with the width Win of the incident X-ray. In this embodiment, the angle between the first crystal and the second crystal is 11.5.
With respect to the Cu-Kα ray from the X-ray source 1, the magnification of the emission width with respect to the X-ray incidence width was set to 9 times. The measurement procedure in this embodiment is the same as that in the embodiment of FIG. In the present embodiment, the divergence angle width of the outgoing X-rays from the channel cut crystal is three times smaller than the incident angle width of the incident X-rays. This indicates that the parallelism of the X-rays incident on the sample 4 is increased, and the blur due to the angular spread of the reflected X-rays from the sample 4 is suppressed. This has the effect of increasing the measurement accuracy.

FIG. 7 shows a configuration diagram of an in-plane distribution measuring apparatus according to another embodiment to which the present invention is applied. The sample 4 is irradiated with wide X-rays 3 having an X-ray wavelength of 1.24 °. Cu from sample 4
X-rays emitted at the total reflection angle of K-ray fluorescent X-rays (excitation rays) are measured by the X-ray detector 6 through the solar slit 12. The solar slit 12 limits the emission angle of the fluorescent X-rays from the sample 4 and limits the light emitting area of the sample 4 in the x ′ direction. The X-ray detector 6 has Charge Cou
A pled device (CCD) was used. This CCD is a two-dimensional position-sensitive detector and can measure the wavelength of the measurement X-ray with high resolution. In this measurement, Cu-
Only the K line processed the signal. By this measurement, the X-ray intensity I (x ′, φ) of the Cu—K line from the sample is obtained. Here, I (x ′, φ) is proportional to the amount of Cu element on the surface of the sample. Next, the sample 4 is rotated by a small angle δφ (0.5 degrees in this embodiment) about the z ′ axis,
(X ′, δφ) is obtained. This scanning is repeated until the rotation angle of the sample 4 becomes 180 degrees. From these series of measurements, I (x ′, φ) is obtained. Finally, I (x ', φ)
Using the computer tomography algorithm (filter back projection in this embodiment) described in the section of the operation, I (x, y) on the sample, that is, the surface of the Cu element amount distributed on the sample surface Inner distribution can be determined.

In this embodiment, the position resolution of the CCD in the x 'direction was 20 μm, and 512 points were measured in the x' direction. The number of rotations of the sample 4 with respect to the z ′ axis is 360 points.
From this, the resolution of the in-plane distribution in the sample is about 20 μm, which indicates that the resolution can be measured with a much smaller resolution than the irradiation region of the sample and nondestructively. In the present embodiment, since the fluorescent X-rays taken at the angle of total reflection from the sample 4 are measured, there is an effect that the distribution amount of the element at a depth of about several Å from the surface of the sample can be measured.
Also, as the take-out angle is increased, the depth of interest of the sample can be changed. Therefore, the signal from the CCD is processed two-dimensionally at multiple wavelengths I (x ′, φ, z ′, E)
By doing so, there is an effect that it is possible to measure the in-plane distribution including multiple elements and also including the depth direction.

In the embodiments described above, X-rays are used as electromagnetic waves. However, the present invention can be applied to electromagnetic waves such as radio waves, infrared rays, visible light, ultraviolet rays, soft X-rays, and γ-rays. In that case, the interaction between each electromagnetic wave and the substance is different, so that the obtained in-plane distribution of the physical quantity is different. For example, in the case of infrared rays, the in-plane distribution of molecular orientation on the sample, the thickness and density of the sample in the case of a visible laser beam, and in the case of soft X-rays, the thickness, refractive index, and density of the light element of the sample. Are obtained.

[0046]

As described above, according to the present invention,
From a series of measurements of electromagnetic waves incident on the sample from multiple directions and reflected from the sample and measuring the electromagnetic waves emitted from the sample by irradiating the sample with electromagnetic waves,
There is an effect that the in-plane distribution of the physical quantity of the sample based on the interaction between the electromagnetic wave and the substance can be measured with a much smaller resolution than the sample irradiation region of the electromagnetic wave and nondestructively.

Further, in the calculation processing for obtaining the in-plane distribution of the physical quantity of interest from the measurement of the electromagnetic waves from the sample, it is possible to use a computer tomography algorithm that is generally used or a hardware processor dedicated to fast Fourier transform. This has the effect that the calculation of the in-plane distribution of the physical quantity can be speeded up.

Further, according to the in-plane distribution measuring apparatus of the present invention, there is provided a mechanism for irradiating the sample with electromagnetic waves from many directions, or a mechanism for detecting electromagnetic waves reflected or excited from the sample in many directions. Thus, the present invention can be easily realized. Further, since it is only necessary to incorporate the above mechanism, it can be easily applied to existing devices.

[Brief description of the drawings]

FIG. 1 shows a sample of the present invention in which electromagnetic waves (X
1 is an overall configuration diagram of an in-plane distribution measuring apparatus according to an embodiment including a mechanism for irradiating a line.

FIG. 2 is a conventional film thickness measuring apparatus using X-rays as electromagnetic waves.

FIG. 3 is a schematic diagram showing an example of a reflection X-ray profile.

FIG. 4 is a diagram of a calculation model for calculating X-ray reflection intensity when a single thin film is present on a substrate.

FIG. 5 is a diagram showing the principle of irradiating a sample with electromagnetic waves from a number of directions and obtaining the in-plane distribution of physical quantities relating to the sample from a series of measurements of the electromagnetic waves reflected from the sample.

FIG. 6 is a diagram showing a principle of expanding an X-ray width by an asymmetric reflection crystal.

FIG. 7 is a configuration diagram of an in-plane distribution measuring apparatus according to an embodiment including a mechanism for detecting electromagnetic waves (fluorescent X-rays) excited in multiple directions from a sample according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 X-ray source (electromagnetic wave generation source) 2 Slit 3 Incident X-ray (electromagnetic wave) 4 Sample 5 Emission or excitation X-ray (electromagnetic wave) 6 X-ray detector (electromagnetic wave detector) 7 Sample holder 8 Detector stand 9 Control Container 10 Channel cut crystal 11 Fluorescent X-ray 12 Solar slit

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-64-6850 (JP, A) JP-A-64-7730 (JP, A) JP-A-4-218754 (JP, A) 22582 (JP, B2) JP 1-36061 (JP, B2) (58) Fields surveyed (Int. Cl. ⁶ , DB name) G01N 23/00-23/227

Claims (9)

(57) [Claims] 1. A method in which a viewing angle with respect to a sample surface is changed.
The operation of irradiating the sample surface with the electromagnetic wave
Relative to the direction of electromagnetic wave irradiation
Repeatedly while shifting the rotation position in the
Series in as measured by the reflection wave detection means, based on the mutual positional relationship of the reflection wave and the irradiating electromagnetic wave detected by said detecting means, a computer tomography
The arithmetic analysis processing by, anticipation from the detecting means
Over a physical quantity of the sample corresponding to the small old region Ri by irradiation area of the electromagnetic wave on the sample surface to be measured entire region specimen
Plane distribution measurement method characterized by obtaining the in-plane distribution of the sample of the physical quantity by determined Mel that Te. 2. A series to be measured by the detecting means with the mutual positional relationship between a large number of electromagnetic waves that will be emitted from the sample surface in multiple directions by irradiating electromagnetic waves from multiple directions on the sample surface, by the detection means Based on a large number of detected outgoing electromagnetic waves and their mutual positional relationship , computerized
The detection method can be performed by arithmetic
From the irradiation area of the electromagnetic wave on the sample surface ,
Plane distribution measurement method characterized by obtaining the in-plane distribution of the sample of the physical quantity by determined Mel it over the measurement area entire specimen the physical quantity of the sample corresponding to the small old region Ri. A sample holding means for holding 3. A sample entrance of an electromagnetic wave generation source to be incident an electromagnetic wave to said sample, detecting means for detect the reflected waves reflected from the front Symbol sample, to the sample of the incident electromagnetic wave A position changing mechanism that changes the direction while specifying the mutual positional relationship, and a series of multiple reflected electromagnetic waves detected by the detection means corresponding to each incident direction of the incident electromagnetic wave and a mutual positional relationship between the incident electromagnetic waves. Te, the arithmetic analysis processing by a computer tomography method, determined a physical quantity of the sample corresponding to the small old region Ri by irradiation area of the electromagnetic wave on anticipation than the detecting means and the sample surface over the measurement area entire specimen And an in-plane distribution calculation processing means for obtaining an in-plane distribution of the sample of the physical quantity by adjusting the position of the incident electromagnetic wave.
The operation of changing the viewing angle with respect to the sample surface is performed by the electromagnetic wave
The direction of electromagnetic wave irradiation on the sample surface with the normal to the irradiation area
An in-plane distribution measurement apparatus characterized in that the measurement is repeatedly performed while the rotational position is relatively shifted with respect to . 4. A sample holding means for holding a sample, an electromagnetic wave source for irradiating the sample with electromagnetic waves, a detecting means for detecting an emitted electromagnetic wave emitted from the sample in response to the irradiated electromagnetic waves, and And a position changing mechanism that changes the relative position of the detecting means while specifying the mutual positional relationship thereof, based on a series of a large number of reflected electromagnetic waves detected for each position by the detecting means and their mutual positional relationship ,
The operation analysis processing by a computer tomography method, a physical quantity of the sample corresponding to the small old region Ri by irradiation area of the electromagnetic wave on the sample surface in anticipation from the detecting means
Plane distribution measuring apparatus characterized by comprising a plane distribution computing means for obtaining the in-plane distribution of the sample of the physical quantity by Mel calculated over the measurement area entire specimen. 5. The in-plane distribution measuring apparatus according to claim 3, wherein the position changing mechanism is a mechanism in which the sample holding unit rotates the sample around a normal direction of a surface of interest of the sample. An in-plane distribution measuring device characterized by being formed. 6. The in-plane distribution measuring apparatus according to claim 3, wherein the position changing mechanism rotates the electromagnetic wave generating source and the electromagnetic wave detecting means around a normal direction of a plane of interest of the sample. An in-plane distribution measuring device formed by a mechanism. 7. The in-plane distribution measuring apparatus according to claim 3, wherein the sample holding unit moves the sample in a direction orthogonal to a traveling direction of an electromagnetic wave emitted from the electromagnetic wave generation source. An in-plane distribution measuring device, comprising: 8. The in-plane distribution measuring apparatus according to claim 3, wherein the electromagnetic wave generating source and / or the electromagnetic wave detecting means move in a direction orthogonal to a normal direction of a plane of interest of the sample. An in-plane distribution measuring device comprising a mechanism. 9. The in-plane distribution measuring device according to claim 3, wherein the electromagnetic wave detecting means uses an electromagnetic wave detector that detects the electromagnetic wave through a narrow gap, and generates the electromagnetic wave from the sample. An in-plane distribution measuring device characterized in that an area is limited.