JPH07286977A - X-ray analysis device and x-ray analyzing method - Google Patents

Abstract

PURPOSE:To enable accurate analysis to be conducted even if the intensity of primary X-rays is changed by processing the intensity of secondary X-rays by the intensity of primary X-rays, and thereby eliminating the effect of change in the intensity of primary X-rays. CONSTITUTION:Primary X-rays from a X-ray source are diffracted by an artificial lattice 2, and formed into monochromatic light so as to be incident on a specimen 4 at an appropriate incident angle phi, and it is then detected by a detector (transmission type proportion counting tube) 3, so that its intensity is thereby detected. Secondary X-rays generated by the specimen 4 is then detected 6 so as to be detected 8 of its intensity, and a strength ratio with the primary X-rays is computed 9, so that a relative relation between the strength ratio and the incident angle phi is thereby formed 10. An adjuster 5 is so designed that the rotation angle of a specimen table 11 is set to be an incident angle phi most suitable to total reflection based on the strength ratio and the relative relation, and also that the change of the strength of the secondary X-rays with respect to the angle phi can be automatically detected 6. By this constitution, since the strength of the secondary X-rays is changed proportionally with the strength of the primary X-rays even if the latter is changed, a relation between a strength ratio and the concentration of the specimen 4 is not needed, so that correct concentration can thereby be detected at all times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an X-ray analyzer and an X-ray analyzer.
The present invention relates to a line analysis method.

[0002]

2. Description of the Related Art Conventionally, for example, a total reflection type X-ray fluorescence analyzer has been used as an apparatus for detecting impurities adhering to the surface of a sample. At this time, first, it is necessary to appropriately set the incident angle of the primary X-ray irradiated on the sample according to the main component of the sample to be analyzed.
As indicated by a solid line P in (a), the correlation between the incident angle φ and the intensity of a typical fluorescent X-ray from the sample, for example, the intensity Isi of the Si-Kα line when the sample is a silicon wafer is set aside. , Was used as a reference for setting the incident angle in the later analysis.

Further, in the case of component analysis in a sample, for example, when the sample is a silicon wafer and the concentration of copper Cu contained in the sample is measured, in the conventional case, the concentration of Cu is first known and the concentrations are different from each other. Using a plurality of standard samples, a fluorescent X-ray Cu-as shown by a solid line S in FIG.
A concentration curve of the intensity ICu of the Kα ray and the concentration of Cu was prepared. This is called a calibration curve. Then, the Cu concentration h (%) was obtained from the point H on the calibration curve S having an intensity that matches the intensity ICu of the Cu-Kα ray from the sample to be analyzed, and it was assumed that the correct concentration was obtained.

[0004]

However, in reality, 1
The intensity of the next X-ray changes due to various causes, and proportionally to 2
The intensity of the fluorescent X-ray which is the next X-ray also changes. Therefore,
The setting of the incident angle of the primary X-ray on the sample and the analysis of the components in the sample in the above-described conventional techniques cannot sufficiently support the precise analysis required today. The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide an X-ray analysis apparatus and an X-ray analysis method that can always perform accurate analysis even if the intensity of primary X-rays changes. And

[0005]

In order to achieve the above object, an X-ray analysis apparatus according to the present invention comprises an X-ray source for generating primary X-rays for irradiating a sample, and the primary X-rays. A first detector for measuring the intensity of the X-ray, a first intensity detecting means for obtaining the intensity of the X-ray detected by the first detector, and a second detector for detecting the secondary X-ray generated from the sample The second intensity detecting means for obtaining the intensity of the X-ray detected by the second detector and the intensity of the secondary X-ray obtained by the second intensity detecting means are obtained by the first intensity detecting means. And a data processing means for processing by the intensity of the primary X-rays to remove the influence of the intensity change of the primary X-rays.

According to this apparatus, in setting the incident angle of the primary X-ray on the sample, the intensity of the secondary X-ray is processed so as not to be affected even if the intensity of the primary X-ray changes. Every
It is possible to obtain the correlation between the data on the intensity of the processed secondary X-ray and the incident angle of the primary X-ray on the sample. Therefore, the optimum incident angle can always be set based on this correlation.

In the analysis of the components in the sample, the primary X
Secondary X so that it is not affected even if the intensity of the line changes
It is possible to process the intensity of the line and prepare a concentration curve of the data regarding the intensity of the processed secondary X-ray and the concentration of the component to be measured to obtain a calibration curve. Therefore, the correct component concentrations can always be obtained based on this calibration curve, and no correction is necessary. Even when the occurrence of the escape peak is a problem, the primary X
The measurement error due to the escape peak can be accurately eliminated without being affected by the change in the line intensity.

As the first detector, it is possible to use a transmission type detector which is installed in the optical path from the X-ray source to the sample and detects the intensity of the primary X-ray while transmitting it. As this transmission type detector, it is preferable to use a proportional counter having a discharge medium having a low primary X-ray absorption rate. When such a proportional counter is used, it is not necessary to move it from the optical path of the primary X-ray in order to avoid loss of the primary X-ray there even when the proportional counter is not used. Therefore, since the proportional counter can be left installed in the optical path, the structure of the X-ray analyzer can be simplified. In addition, the proportional counter with such a discharge medium has a primary X
Since there is a filter effect that absorbs high-energy components and low-energy components in the line, the first-order X that is not sufficient for artificial lattices
Higher precision analysis is possible by supplementing the line monochromatization.

The absorptance of the discharge medium for primary X-rays is preferably 5% or more and 20% or less (5 to 20%), more preferably 5 to 15%, and further preferably 5 to 5.
It is 10%. When Au-Lα rays or Pt-Lα rays are used as the primary X-rays, krypton gas or neon gas can be used as the discharge medium.
Generally, a proportional coefficient tube uses a discharge medium such as argon gas or xenon gas, which has a large absorption rate of incident X-rays, in order to improve counting efficiency. On the other hand, in the present invention, the primary X
Contrary to common sense, in order to increase the amount of transmission of rays, the primary X
A line with a low absorption rate is used.

As the data processing means, the intensity ratio between the intensity of the secondary X-ray obtained by the second intensity detecting means and the intensity of the primary X-ray detected by the first intensity detecting means. It is possible to use intensity ratio calculation means for calculating

Further, in a preferred embodiment of the present invention, an adjuster for adjusting the incident angle of the primary X-ray on the sample each time the secondary X-ray intensity detection by the second intensity detection means is completed, Correlation creating means for obtaining a correlation between the incident angle and the intensity ratio calculated by the intensity ratio calculating means is provided. According to the adjuster and the correlation creating means, the correlation creation and the incident angle setting for the above-described incident angle setting can be automatically performed.

In the X-ray analysis method according to the present invention, first, the intensity of the primary X-ray generated from the X-ray source is detected while the primary X-ray is transmitted and the sample is irradiated with the primary X-ray. The secondary X-ray generated from the sample is detected and the intensity of the secondary X-ray is calculated while adjusting the incident angle of. Next, a ratio between the obtained intensity of the secondary X-ray and the detected intensity of the primary X-ray is calculated, and the correlation between the incident angle of the primary X-ray and the calculated intensity ratio. Find the relationship in advance. Then, based on this correlation, the incident angle of the primary X-ray is set from the intensity ratio calculated as described above for the sample to be analyzed. According to this X-ray analysis method, the correlation creation and the incident angle setting for the above-described incident angle setting can be automatically performed.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the X-ray analysis apparatus according to this embodiment first has an X-ray source 1. A primary X-ray, for example, gold (A
u) -Lβ rays are diffracted and monochromatic by the artificial lattice 2 installed so that the primary X-rays are incident at an appropriate angle. The diffracted first-order X-rays are detected by the first detector 3 installed in the optical path. In this embodiment, as the first detector 3, a transmissive proportional counter 3 using krypton gas as a discharge medium is used. The intensity of the X-ray detected by the proportional counter 3 is obtained by the first intensity detecting means 7.

Here, since the proportional counter 3 using krypton gas as the discharge medium is used, the Au-L in the primary X-ray is particularly used.
Absorption rate of α, Lβ, Lγ rays is extremely low at about 10%, and when the proportional counter 3 is not used, the primary X
It is not necessary to move from the optical path of the primary X-rays to avoid line losses. Therefore, since the proportional counter 3 can be left installed in the optical path, the structure of the X-ray analyzer can be simplified. Furthermore, since the proportional counter tube 3 using krypton gas as the discharge medium has a filter effect of absorbing high energy components and low energy components in the primary X-rays which hinder the analysis,
The artificial lattice 2 compensates for the insufficient monochromaticity of the primary X-rays and enables higher-precision analysis.

The absorption rate of the discharge medium of the proportional counter tube 3 for the primary X-rays is preferably 5 to 20%, more preferably 5%.
-15%, more preferably 5-10%. In general, the proportional coefficient tube 3 uses a discharge medium such as argon gas or helium gas, which has a large absorption rate of incident X-rays, in order to improve counting efficiency. On the other hand, in the present invention, in order to increase the amount of transmitted primary X-rays, contrary to common sense, a material having a low primary X-ray absorption rate is used.

After that, the primary X-ray is irradiated onto the sample 4 at an incident angle φ. The secondary X-ray generated from the sample 4 is detected by the second detector 6 installed at an appropriate position relative to the sample 4. The intensity of the X-ray detected by the second detector 6 is obtained by the second intensity detecting means 8. Every time the detection of the intensity of the secondary X-ray by the second intensity detecting means 8 is completed, the sample stage 11 on which the sample 4 is fixed is rotationally driven by the adjuster 5 to adjust the incident angle φ of the primary X-ray. The adjuster 5 has a built-in drive such as a step motor, and rotates the sample table 11 by a fixed amount. The intensity of the secondary X-ray obtained by the second intensity detecting means 8,
The intensity ratio with the intensity of the primary X-ray obtained by the first intensity detecting means 7 is calculated by the intensity ratio calculating means 9 which is an example of the data processing means. The correlation between the intensity ratio and the incident angle φ is obtained by the correlation creating means 10.

In this way, the change of the secondary X-ray intensity with respect to the change of the incident angle φ can be automatically obtained by the adjuster 5 and the correlation creating means 10. The regulator 5
On the basis of the obtained correlation, the rotation angle of the sample table 11 is set so that the incident angle φ optimum for total reflection is obtained from the intensity ratio calculated by the intensity ratio calculating means 9 for the sample 4.

Next, the operation of the above configuration will be described. First, in a total reflection X-ray fluorescence analyzer or the like, it is necessary to appropriately set the incident angle φ according to the main component of the sample 4 to be analyzed. Because if the incident angle φ is too large,
Total reflection does not occur, unnecessary scattered X-rays other than the fluorescent X-rays to be analyzed from the sample 4 are incident on the second detector 6 in a large amount, and precise analysis becomes difficult. This is because if it is too small, most of the primary X-rays incident on the sample 4 are reflected and fluorescent X-rays of sufficient intensity for analysis cannot be obtained.

Therefore, conventionally, as shown by a solid line P in FIG. 2 (a), the incident angle φ and the second intensity detecting means 8 are previously set.
A typical fluorescent X-ray intensity from the sample 4 (FIG. 1) obtained in (FIG. 1), for example, in the case where the sample 4 is a silicon wafer, was correlated with the intensity ISi of Si—Kα ray. On the solid line P, the point A is in a state where the incident angle φ is too large, the point B is in a too small state, and the point C is in a properly set state. Therefore, when another silicon wafer is to be analyzed after this correlation is created, the incident angle φ is set so that the intensity Isi of the Si-Kα ray generated from the silicon wafer coincides with the Isi at the point C. , And that the optimum incident angle φc at which total reflection is obtained was set.

In the conventional method of setting the incident angle φ, as can be seen from the fact that the intensity of the secondary X-ray from the sample 4 changes in proportion to the intensity of the primary X-ray, the intensity of the primary X-ray is It is assumed that it is always constant. However, in reality,
In an X-ray source 1 (FIG. 1) such as an open X-ray tube, the target rotates for cooling to withstand a long-term electron collision,
The intensity of the primary X-rays is unstable because the filament components are deposited on the target or the vacuum degree of the space where the X-ray source 1 is placed is unstable.

If the intensity of the primary X-ray is lowered,
Since the intensity of the secondary X-ray from the sample 4 also decreases in proportion thereto, the correlation actually changes as shown by the dotted line Q in FIG. 2 (a). Nevertheless, as in the conventional case, the strength Isi at the time of analysis is I at the C point.
When the incident angle φ is set so as to match Si, the incident angle φd at the point D on the dotted line Q is set, and the optimum incident angle, that is, the incident angle φc at the point C on the solid line P is not set. Therefore, the conventional incident angle φ
The setting method of does not adequately support the precise analysis required today.

In view of the above problems, in this embodiment, the secondary X-ray intensity obtained by the second intensity detecting means 8 (FIG. 1) and the intensity obtained by the first intensity detecting means 7 (FIG. 1) Based on the intensity of the next X-ray, the intensity ratio calculating means 9 (FIG. 1) causes the intensity ratio of the intensity of the secondary X-ray to the intensity of the primary X-ray, for example, Si-Kα when the sample 4 is a silicon wafer. Line Strength Isi and 1
The intensity ratio Isi / IAu of the next X-ray intensity IAu is calculated, and the correlation between this intensity ratio Isi / IAu and the incident angle φ is determined by the correlation creating means 10 (FIG. 1).

The solid line R in FIG. 2B shows this correlation. On the solid line R, point E is a state where the incident angle φ is too large, point F is too small, and point G is a properly set state. If you ask for this, then even the first X
Even if the intensity of the line changes, the intensity of the secondary X-ray from the sample 4 also changes in proportion to it, so that the correlation between the intensity ratio ISi / IAu and the incident angle φ remains unchanged. Therefore, the intensity ratio ISi / IAu in the case of trying to analyze is G on the solid line R.
If the incident angle φ is set so as to match ISi / IAu at the point, the optimum incident angle φg is always set. According to the adjuster and the correlation creating means, the correlation creation and the incident angle setting for the above-described incident angle setting can be automatically performed.

Next, the component analysis in the sample 4 (FIG. 1), for example, the sample 4 is a silicon wafer and copper Cu contained therein
The operation in the case of measuring the concentration will be described.
In the prior art, first, using a plurality of standard samples having known Cu concentrations and different concentrations, the intensity ICu of the secondary X-ray Cu-Kα line as shown by the solid line S in FIG. And a concentration curve of Cu concentration was created. This is called a calibration curve. And Cu- from the sample 4 to be analyzed
The concentration h (%) of Cu was determined from the point H on the calibration curve S having the intensity corresponding to the intensity I Cu of the Kα ray, and it was assumed that the correct concentration was obtained.

However, as described above, the primary X
The intensity of the X-ray is unstable, and if the intensity of the primary X-ray is reduced, the intensity of the secondary X-ray from the sample 4 is also reduced in proportion to it, so that the calibration curve is actually shown in FIG. It is changed as shown by the dotted line T in (a). Nevertheless, when the Cu concentration h (%) is obtained from the point H on the calibration curve S having the intensity I Cu of the Cu-Kα ray from the sample 4, the correct concentration, that is, the calibration curve T after the fluctuation is obtained. The density i (%) at the point I above cannot be obtained. Therefore, the above-mentioned conventional component analysis method cannot sufficiently deal with the precise analysis required today. In addition, in order to perform a precise analysis, using a plurality of standard samples when the calibration curve S was created,
The corrected calibration curve T shown by the dotted line needs to be created for each analysis.

In view of the above problems, in this embodiment, the intensity of the secondary X-ray obtained by the second intensity detecting means 8 (FIG. 1) and the intensity of the secondary X-ray obtained by the first intensity detecting means 7 (FIG. 1) Based on the intensity of the next X-ray, the intensity ratio calculating means 9 (FIG. 1) calculates the intensity ratio of the intensity of the secondary X-ray and the intensity of the primary X-ray, for example, the sample 4 is a silicon wafer and is made of copper Cu. When measuring the concentration, the intensity ratio ICu / IAu between the intensity ICu of the Cu-Kα ray and the intensity IAu of the primary X-ray from the sample 4 is calculated, and the intensity ratio ICu / IAu and the concentration of Cu are calculated. A concentration curve was created and used as a calibration curve.

This calibration curve U is shown by a solid line in FIG.
If this is determined, even if the intensity of the primary X-ray changes thereafter, the intensity of the secondary X-ray from the sample 4 also changes in proportion to it, so that the intensity ratio ICu / IAu and the concentration of Cu are The relationship is constant. Therefore, the correct Cu concentration j (%) is always obtained from the point J on the calibration curve U having the intensity ratio that matches the intensity ratio ICu / IAu in the case of analysis.
There is no need for correction.

Next, the case where this embodiment is applied to eliminate the measurement error due to the escape peak will be described. For example, when the concentration of copper Cu contained in the silicon wafer is measured by using Au-Lα ray as the primary X-ray, the Au-Lα ray scattered by the sample 4 (FIG. 1) is the second detector 6 (FIG. 1). ) And the second detector 6 is, for example, a semiconductor detector using a silicon-lithium single crystal, it excites the silicon to generate Si-Kα rays and loses energy, resulting in a so-called escape peak. appear. The energy of this escape peak is the energy of the Au-Lα line (9.712
The value obtained by subtracting the energy (1.739 kev) of Si-Kα ray from kev is 7.973 kev, which is difficult to distinguish from the Cu-Kα ray (energy 8.04 kev) to be measured. That is, the intensity I Cu of the Cu—Kα ray from the sample 4 obtained by the second intensity detecting means 8 (FIG. 1) apparently includes the intensity of the escape peak.

Therefore, X near the measured Cu-Kα ray
The intensity of the escape peak is subtracted from the line intensity (the intensity of the true Cu-Kα line plus the intensity of the escape peak) to obtain the intensity of the Cu-Kα line. Here, when the intensity of the primary X-ray Au-Lα ray changes, the intensity of the scattered X-ray in the sample 4, and thus the intensity of the escape peak to be subtracted, also changes in proportion to this. Therefore, Cu
If the intensity of the escape peak and the intensity of the scattered X-ray are obtained by the second intensity detecting means 8 using a sample that does not contain, and the proportional relationship between them is known, even in a sample in which the Cu concentration is unknown, The intensity of the scattered X-ray can be obtained by the second intensity detecting means 8 and the intensity of the escape peak can be obtained from the proportional relationship. Then, the intensity of the escape peak can be subtracted from the X-ray intensity in the vicinity of the Cu-Kα line obtained by the second intensity detection means 8 to obtain the true intensity of the Cu-Kα line, but it is possible to obtain the intensity of the conventional Cu-Kα line as shown in FIG. In the calibration curve as shown in a), if the intensity of the primary X-ray Au-Lα ray changes, the calibration curve to which the intensity of the true Cu-Kα ray should be applied also changes. Therefore, the measurement error due to the escape peak cannot be accurately eliminated.

In view of the above-mentioned problems, in the present embodiment, the measurement error due to the escape peak is determined as follows by the primary X-ray A
It has been made possible to accurately solve the problem without being affected by the intensity change of the u-Lα ray. First, using the sample containing no Cu, the scattered X-ray Au − was detected by the second intensity detecting means 8 (FIG. 1).
The intensity ISC of the Lα ray is obtained, and the intensity ratio ISC / the intensity XA of the primary X-ray Au-Lα ray obtained by the first intensity detecting means 7 is calculated.
IAu is calculated by the intensity ratio calculation means 9. In parallel with this, the intensity IEP of the escape peak is detected by the second intensity detector 8.
And the primary X-ray Au obtained by the first intensity detecting means 7
The intensity ratio calculation means 9 calculates the intensity ratio IEP / IAu with respect to the intensity IAu of the −Lα line. And these intensity ratio ISC / IA
A proportional relationship between u and IEP / IAu, that is, a correlation is obtained. This correlation is shown by the solid line V in FIG.

In obtaining the correlation line, the intensity of scattered X-rays I is obtained by rotating the sample containing no Cu, for example, a semiconductor wafer around an axis perpendicular to its main surface.
Change SC. That is, when the wafer is rotated, a diffraction line of the primary X-ray Au-Lα line is generated at a specific rotation position, and this is incident on the second detector 6 as a kind of scattered X-ray, and the intensity ISC of the scattered X-ray is changed. Increase. IEPs are measured for a plurality of different ISCs obtained in this way, and a straight line passing through the vicinity of the measurement points is obtained by the least-squares method and used as a correlation line.

Now, in a sample whose Cu concentration is unknown,
When the intensity ratio ISC / IAu is calculated by the intensity ratio calculating means 9 (FIG. 1), the intensity IEP of the escape peak and the primary X are calculated from the point K on the solid line V having the intensity ratio corresponding to it in FIG. Intensity ratio IEP / IAu of intensity Au-Lα ray to intensity IAu
Can be read as k. Therefore, in FIG. 3B, the X-ray intensity Ix in the vicinity of the Cu-Kα line calculated by the intensity ratio calculating means 9 (the intensity IEP of the escape peak added to the intensity ICu of the true Cu-Kα line) If the value obtained by subtracting k from the intensity ratio IX / IAu of the intensity of the primary X-ray Au-Lα ray to the intensity IAu is applied to the calibration curve U as the correct intensity ratio ICu / IAu, the correct Cu concentration m (%) is obtained. can get. Therefore,
In this embodiment, the measurement error due to the escape peak is 1
It can be resolved accurately without being affected by the intensity change of the next X-ray.

In the embodiment shown in FIG. 1, the proportional counter 3 using krypton gas as the discharge medium is Au-Lα, L.
Not only β, Lγ rays, but also platinum (Pt) -Lα, Lβ,
The absorption rate for Lγ rays is also extremely low at about 10%. Therefore, the proportional counter 3 can be used even when the primary X-ray is Pt.

A proportional counter using neon gas as a discharge medium is also used for Au-Lα, Lβ, Lγ rays and Pt-Lα,
Since the absorption rate for Lβ and Lγ rays is extremely low at about 10%, it can be preferably used as the proportional counter 3.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an X-ray analysis apparatus showing an embodiment of the present invention.

FIG. 2 is a correlation diagram for setting an incident angle in the related art and the present invention.

FIG. 3 is a diagram showing a calibration curve for copper concentration measurement in the conventional method and the present invention.

FIG. 4 is a correlation diagram for eliminating a measurement error due to an escape peak in the present invention.

[Explanation of symbols]

1 ... X-ray source, 3 ... First detector, 4 ... Sample, 5 ... Adjuster,
6 ... 2nd detector, 7 ... 1st intensity detection means, 8 ... 2nd intensity detection means, 9 ... intensity ratio calculation means (data processing means), 1
0 ... Correlation creating means, φ ... Incident angle.

Claims (6)

[Claims] 1. An X generating a primary X-ray that is irradiated onto a sample.
A radiation source, a first detector for measuring the intensity of the primary X-ray, a first intensity detecting means for obtaining the intensity of the X-ray detected by the first detector, and a secondary X-ray generated from the sample A second detector for detecting the intensity of the X-ray, a second intensity detector for obtaining the intensity of the X-ray detected by the second detector, and an intensity of the secondary X-ray obtained by the second intensity detector,
An X-ray analysis apparatus comprising: a data processing unit that processes the primary X-ray intensity obtained by the first intensity detection unit to remove the influence of the intensity change of the primary X-ray. 2. The device according to claim 1, wherein the first detector is
An X-ray analyzer comprising a transmission type detector installed in the optical path from the X-ray source to the sample to detect the intensity of the primary X-ray while transmitting the same. 3. The X-ray analysis apparatus according to claim 2, wherein the transmission type detector is a proportional counter having a discharge medium having a low primary X-ray absorption rate. 4. The data processing unit according to claim 1, wherein the intensity of the secondary X-ray obtained by the second intensity detecting unit and the intensity of the primary X-ray obtained by the first intensity detecting unit are used. An X-ray analysis apparatus comprising intensity ratio calculation means for calculating a ratio. 5. The adjusting device according to claim 2, further comprising an adjuster that adjusts an incident angle of the primary X-ray to the sample every time the secondary intensity detection by the second intensity detecting unit is completed. An X-ray analysis apparatus comprising: a correlation creating unit that obtains a correlation between an angle and the intensity ratio calculated by the intensity ratio calculating unit. 6. The primary X-ray generated from the X-ray source is transmitted while being transmitted to the sample by detecting its intensity, and the primary X-ray is generated from the sample while adjusting the incident angle of the primary X-ray to the sample. Detecting the secondary X-rays to obtain the intensity of the secondary X-rays, calculating the ratio of the intensity of the obtained secondary X-rays to the intensity of the detected primary X-rays, The correlation between the incident angle of the next X-ray and the calculated intensity ratio is obtained in advance, and based on this correlation, the intensity ratio of the primary X-ray calculated from the intensity ratio calculated as described above for the sample to be analyzed is calculated. An X-ray analysis method for setting the incident angle.