JPS58135407A - Method for measuring film thickness - Google Patents

Abstract

PURPOSE:To measure the thickness of a film with high accuracy, by irradiating characteristic X rays which produce easily non-interference scattering to a material consisting of a coat containing a light element and a base material having a small generating factor of the non-interference scattering and then selecting and detecting scattered X rays. CONSTITUTION:The Lalpha rays of Rh are irradiated from an X-ray generating source 4 to a sample 3 having a coat of polyester resin formed on an aluminum substrate. A part of scattered or radiated X rays is led to a spectral crystal 6 via a solar slit 5, and only X rays of a waveform which is slightly shifted toward a long wavelength and obtained by giving the non-interference scattering to the Lalpha rays of Rh is led to an X-ray detector 7. The output pulses delivered from the detector 7 are supplied to a scaler/timer 9 via an amplifier 8 to be counted. This count value signal is compared with the stored value of thickness of the film produced based on the measuring data of scattering intensity through an arithmetic storage device 10. Thus the film thickness value is detected and displayed to a display 11. In such a way, the thickness of a coated film is measured with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the thickness of coatings containing one element.

When attempting to non-destructively determine the thickness of a paint layer made of an organic material coated on the surface of an iron plate, it is conventional to irradiate the material mM-xsi* and determine the thickness of the paint layer. Detects fluorescence XS* generated from specific elements contained only in
τ Find the thickness of the paint layer, or the fluorescence of the iron plate from the base material! - the paint layer f: determined by the absorption convention 8tIIl,
The thickness t is determined from the measured value. However, the elements contained in the orange paint layer account for % of the light elements.
Fluorescence is generated from these elements because they are elements with a lower atomic number, such as carbon! The generation efficiency of the fluorescent X-rays is small and a large amount of xIm generation is required.Furthermore, these fluorescent The light attenuates while passing through the paint layer and turns red when detected.Therefore, it is difficult to measure a relatively thick layer of tk-6.
On the other hand, in the method of detecting fluorescent X-rays from an iron plate, which is a bulk material, the energy of 1 * x bell is at one end, so the degree of absorption by the paint element is small, tI/&. Therefore, the change in the X-intensity is small with respect to the change in the thickness of the coating, and it is possible to accurately determine the thickness fkVs@ The present invention solves the drawbacks of the conventional constant method, and In order to determine the generation efficiency of incoherent scattering, it is possible to measure the thickness of a film containing vk@ elements with high precision over a relatively wide thickness range. A novel coating thickness measurement method using a spectroscopic/detection system [This method provides a coating that contains light elements and a base material in which the generation efficiency of incoherent scattering is smaller than that of the wrinkled coating. The incoherent scattering of black-characteristic ZSt from the coating side is applied to the material, and as a result, the wavelength of the characteristic X-rays among the X-rays emitted or transmitted from the sample is slightly increased. It is characterized in that At1 of the LX coat is selected and detected, and the thickness tm of the coating is determined based on the correlation information between the detected signal value, the coating thickness measured in advance, and the detected signal value. Above all, the basic idea of the present invention 5ζsP will be explained.

V& writing, for example on the aluminum laminate board 1, like the 1st-
Sample 3 coated with ζ polyester tree 11 and having T coating 2
For example, rhodium (lh) La411 is irradiated from a direction that is at an angle to
Assuming that it is detected at XIa', which is incoherently moved in the k direction, the detection strength at that time is as follows. however,
The incidence Xla'la degree tX, the scattering efficiency in the coating layer and the substrate t8nfsf, and the mass absorption coefficient of the coating layer and the substrate are respectively j11. μ, and their densities are fi, *IH
shall be.

The incident-intensity 1 (X) at the point X of the film WIm to III in 1lIllII is
,,,)...fist (1) and 'ni', it is scattered at the mu point and left behind at the 115 points of 11 membrane 2 t incoherent formation LXIm
Intensity X,'(x) is Ia'(K) = Ia(x)・f
axy (-(Rf'); 1 Ptt't#) x 1...axis (z).Also, the class that reaches the angle of the incident X@fI@film 2 and the base I[ The incoherent scattering intensity X, '(y) is C: Cj) ・Ibc, y no thousand is scattered at 8 points and reached at coating table 1111-★. 'eQ(-(RP+A7
3sp, /A, 4muichi @ 14). Therefore, assuming that the thickness of the substrate is the thickest, the technique is rewarded as follows.

Therefore, in the end, X becomes 0...(6
) Here, the terms ``l'' and ts2 on the right side represent the scattering intensity based on the copper layer, and the term ``lIs'' represents the scattering intensity from the substrate. The light elements contained in iI, namely carbon (C), oxygen (O), and hydrogen (■), and the substrate Al (= ram (mul)
) is different from the atomic number by kana 9, so 0 subordinate' is much larger than f', so if Using the above four full electric materials having a known coating III layer, we fixed the incoherent scattering intensity when XflatlI was applied to each of these materials and fixed this intensity by coating It is graphed as a function of thickness t, and from this graph it can be seen that if the X-intensity I turns red in the measurement, the coating thickness t can be determined, but this method can detect it in h-1! The wavelength of the bell is fluorescent xI
Unlike certain cases using m, it is not fixed by the elements contained in 1 [4c (, non-interfering sexual desire at
In the first place, it is possible to select and measure from the X-rays excluding the short wavelength xae' at the IAI+ end depending on the material of the coating and its approximate thickness. Based on the idea (this shows a complete example of the present invention, & is the above-mentioned wisdom sample, and 4 is the Shinsium (
The X-rays from X-ray source 4, which is an X-ray source with Rh) as the negative material, are irradiated with sample 54C and scattered or emitted from sample 6, -Ila of X-rays is NORA. The X-rays are guided through the slit 5 to the spectroscopic crystal 6 ◎The installation angle of the wrinkle spectroscopic crystal is L6
The rays are incoherently scattered and shifted slightly toward longer wavelengthsgn
Selective X-ray detection only at wavelengths obtained with
It is set up like this. The X-detection i17 generates pulses of the number of pulses corresponding to the intensity of xal guided by the spectroscopic crystal 6 per exposure time.
After Yoso's output cover is amplified δ by amplification im8,
The scaler/timer 94C is supplied and, for example, the number of stitches is counted per a certain period of time @scaler/#ima9-
The digital signal that increases the count value is supplied to the arithmetic storage device 10. ◎*mm#c is for samples whose film thicknesses take various known values! @2F111 obtained from all'tll sealed @
A film thickness value t11 table corresponding to each detection signal value created based on the scattered radiation intensity measurement data shown in 1 is stored, and the t11 signal is calculated based on When supplied to the storage device 10, a signal representing the corresponding film thickness value is also outputted to the calculation/storage device 10, and the signal representing the corresponding film thickness value is outputted to the printer.
The display device 1114ζil! shown.

In the present invention as described above, "Jl's interferometric song a
Since the thickness of the coating is measured using t, the wavelength of the detected X-rays is fixed depending on the elements contained in the coating, as in the case of measurement using fluorescence Don't put it away,
Incoherent contrast (I/%) can be arbitrarily selected from among the X-ray tubes with very short wavelengths. In addition, by setting the wavelength of the emitted X-ray to a relatively short wavelength and liquid length with excellent penetration ability, it is possible to measure the thickness of the target with high precision. In TL!, an application example was described in detail using a fluorescent X-ray analyzer that performs crystal spectroscopy when the thickness of an organic paint coated on a metal material is constant. In this case, it is also possible to use aSS (for example, crystal spectroscopy tr1fkwafkIA) using a non-separating instrument needle.

Furthermore, the present invention also provides silicon oxide (
8, o, ) and 5111 1 y (P s's )−
In addition to measuring the thickness sm of a coating called bhb and the thickness II of a nitrided layer treated with silicon, it can also be applied to determining the thickness of an organic film.

[Brief explanation of drawings]

1111+111 is a factor for detailed explanation of the present invention,
Figure mH is a diagram showing the relationship between incoherent scattering intensity and film thickness. 1: γ base plate, 2: coating, 5: sample, 4gX
Im'A4: *, 5: Note txl ts), 6g minute 11° crystal s': "-Detector, 8: Amplification L9: J Koehler/
-Now, 1G-Arithmetic storage device, I chant: l! Display device O Patent originator Nippon

Claims (1)

[Claims] The generation efficiency of incoherent scattering from the coating containing trench elements is smaller than that of the incoherent coating. Shoot, its result Jl#sample! - Out of the emitted or scattered X-rays, select and detect the wavelength of X-rays with one characteristic, which is slightly longer than the wavelength of the X-rays, and detect the detected polarization value and pre-measure W! Based on the correlation information between the determined coating thickness and the detected Confucian pot value, the thickness of one coating is determined to be 8ts at -3v%.