| 摘要 |
PURPOSE:To detect the tomographic image of the soldering part of an electronic circuit module with high resolution by projecting X rays which differ in wavelength band successively. CONSTITUTION:A sample 3 is irradiated with an X ray from an X-ray source 1 and an X-ray detector 2 picks up its transmission image. A voltage controller 9 controls the acceleration voltage of an electron beam supplied to a target 12 to vary the distribution of the spectrum of the generated X ray in a short- wavelength range. Filters 6a-6c are constituted by providing copper plates which are different in thickness and the generated X ray is transmitted through them to attenuate the X-ray intensity in a long-wavelength range and control the X-ray. The sample 3 is mounted on a holder 4 and driven in an X and a Y direction to set an inspection position at the X-ray irradiation position and then the angle theta of the irradiation is set. An X-ray generation voltage and an X-ray filter are switched to radiate the X rays which differ in spectral band successively, and transmission images obtained by the respective X rays are detected and stored in image memories 14a-14n. They are read out properly and processed by a computer 15 to extract an image corresponding to the thickness distribution. |
