JPH0514842B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an apparatus for measuring the thickness of each layer of a multilayer coating and verifying the components of each layer using X-rays.

B. Prior art When performing multilayer plating with a thickness of several μm to several + μm, it is important for quality control to measure the thickness of each layer and verify the components. There was no practical method for non-destructively measuring thickness and verifying components. For example, in this case,
Cut the sample to expose the cross section of the plating layer, measure the thickness and composition of each layer with an X-ray microanalyzer, or observe the cross section of the plating layer with an optical microscope to measure the thickness of each layer, and separate each layer separately. Some methods are used, such as taking samples at different times and testing the components using another method, but these are all destructive tests.

C. Purpose The present invention aims to provide a multilayer film analysis device that can non-destructively and efficiently measure the thickness of each layer of a multilayer film and verify its components.

D. Configuration If the target layer is a plating layer such as chromium, the sample surface is irradiated with a continuous X-ray beam having a wavelength of 1 Å or less that can sufficiently penetrate the layer to be measured.
The wavelength of the X-rays reflected at a certain angle to the ray beam is detected, the components of each layer are verified based on the wavelength and the angle between the incident and reflected X-rays, and the intensity of each layer is determined from the intensity of the reflected X-rays. This allows you to know the thickness.

When the angle between the incident X-ray and the reflected X-ray is known and the X-ray wavelength is detected, the lattice constant of the lattice plane of the crystal in the layer that caused the reflection is determined from the flag reflection conditions, and this is This is information about the components of that layer. Furthermore, if the incident X-ray intensity is constant, the intensity of the reflected X-rays described above increases as the layer thickness increases (because the number of lattice planes contributing to reflection increases).
The intensity of the reflected X-rays provides information on the thickness of each layer.

E. Example First, the principle of the present invention will be explained with reference to FIG.
D is a substrate on which three layers A, B, and C are formed. X is an incident X-ray beam, and continuous X-rays are used. Let the incident angle be θ. X-ray detection is performed in the direction of the incident angle θ. X-ray detection is of a type that can obtain a signal according to the energy, that is, the wavelength, of the X-rays, and uses, for example, an SSD. Figure 2 is a record of the detection output of the SSD, with the horizontal axis representing the energy (wavelength) of the X-ray and the vertical axis representing the X-ray detection intensity. The wavelength λa is the reflection from the A layer, λb is the reflection from the B layer, and λc is the reflection from the C layer. In layer A, X-rays with wavelength λa are reflected at a reflection angle θ. The interval d between the lattice planes that caused this reflection is determined. For example, if the A layer is alloy plating, this distance d varies depending on the component ratio, so the component ratio can be verified by creating a relationship curve between the component ratio and the lattice constant in advance. Furthermore, even in the case of single metal plating such as chrome plating, the value of d fluctuates when the lattice is distorted due to hydrogen absorption in the plating. Since the lattice is generally distorted by the inclusion of impurities, the purity of the layer can be verified from the difference between the measured d and the d measured with a standard sample. FIG. 3 shows the relationship between the reflection intensity of X-rays of wavelength λa in layer A and the thickness, and the reflected X-ray intensity increases as the layer thickness increases. The relationship between this thickness and the intensity of reflected X-rays can be measured in advance using a standard sample, and the thickness of layer A can be determined from the actually measured X-ray intensity of λa using the graph in Figure 3. can. B
Regarding the layers, I created a graph of the relationship between the thickness of layer A and the absorption of incident X-rays as shown in Figure 4 in advance, and
Since the thickness of the layer has already been determined as described above, the absorption of incident X-rays by layer A is determined from the graph in Figure 4, and the intensity of reflected X-rays (X-rays with wavelength λb) from layer B is determined. is converted to the case where the incident X-ray intensity to the B layer is a reference value, and the thickness of the B layer is determined for the A layer using a graph similar to that shown in FIG. The thickness of the C layer is also determined by the same procedure as above by determining the absorption of the A layer and B layer.

Although it would be quite troublesome if the above-mentioned operation were performed by a human, the data corresponding to Figures 3 and 4, the deviation of the reflected X-ray wavelength from the reflected X-ray wavelength in the standard sample, the component ratio, impurity concentration, etc. By inputting relational data into a computer in advance, the above-mentioned operations can be automated and speeded up.

FIG. 5 shows an embodiment of the present invention. 1 is an X-ray irradiation device consisting of an X-ray source and a solar slit, and irradiates a sample with a parallel X-ray beam. 2 is an X-ray detection device consisting of a solar slit and an SSD detector.
The X-ray irradiation device 1 and the X-ray detection device 2 are attached to a goniometer 3 so as to be able to change their angular positions. In the explanation in Figure 1, the incident angle θ of incident X-rays is the same for each layer, and the reflection angle θ of reflected X-rays is also equal to the incident angle, but there is no need to do so. , the incident angle of the X-rays may be changed for each layer, and there is no need to make the detection direction of the reflected X-rays equal to the incident angle of the incident X-rays. The lattice plane from which the strongest reflected X-rays can be obtained for each layer may be selected. 4 is a sample, 5 is a computer, X-ray irradiation device 1 and
The angular position on the goniometer 3 of the radiation detection device 2 is controlled, information on the wavelength and intensity of reflected X-rays is taken in from the X-ray detection device 2, and the above-mentioned operations are automatically performed using the data measured and stored in advance. and output the results to the printer 6.

Effects According to the present invention, the thickness, composition, etc. of each layer of multilayer plating can be determined non-destructively and quickly (there is no need for labor such as cutting and polishing the sample, and thickness measurement and composition verification can be performed in the same process. It is very effective for quality control of matsuki etc.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention, FIG. 2 is a graph showing an example of the relationship between the wavelength and intensity of reflected X-rays, FIG. 3 is a graph showing the relationship between reflected X-ray intensity and layer thickness, and FIG. Figure 4 is a graph of the relationship between layer thickness and X-ray absorption.
FIG. 5 is a front view of one embodiment of the present invention. 1...X-ray irradiation device, 2...X-ray detection device, 3
...Goniometer, 4...Sample, 5...Computer.

Claims (1)

[Claims] 1. An X-ray irradiation device that irradiates the sample with a continuous X-ray beam, an X-ray detection device that selects the energy of X-rays reflected from the sample, and these devices can be placed at any angle position centered on the X-ray irradiation point of the sample. Information about the components of each layer of the multilayer film is obtained from the angle between the incident X-ray and the reflected X-ray and the wavelength of the reflected X-ray, and the information about the composition of each layer is obtained from the intensity of the reflected X-ray at each wavelength. A multilayer film analysis device characterized by obtaining information regarding thickness.