Electron Probe Micro Analyzer (EPMA) uses the characteristic X-ray for analysis. Therefore the depth of analysis area is spread to a few micrometer. It is difficult to make the quantitative or state analysis of surface thin-film. However, it is possible to measure the thickness of thin-film by using the X-ray intensity ratio between the film and bulk standard specimen under an assumed X-ray depth distribution function. In this paper, a known composition thin-film was measured by EPMA and the result was applied to thin-film area analysis.
Film thickness was measured as mass thickness (ρz) by the intensity ratio of the characteristic X-ray intensities between the thin-film and bulk standard. As the X-ray distribution function ϕ(ρz) the model due to Packwood and Brown1) was used, which is written as.
![](//static.cambridge.org/content/id/urn%3Acambridge.org%3Aid%3Aarticle%3AS1431927600011363/resource/name/S1431927600011363_eqn1.png?pub-status=live)
(1)
An error is thought to exist in the thickness calculation because the backscattering yield near the interface is different when the difference in the atomic numbers is large between the thin-film and the substrate.