System for analyzing metal impurity on the surface of a single crystal semiconductor by using total reflection of x-rays fluorescence

摘要

A system for analyzing a metal impurity at the surface of a single crystal semiconductor comprising: an incident device (1,2) for allowing X-ray to be incident, at an incident angle less than a total reflection angle, onto the surface of a wafer (3) in the form of a thin plate comprised of a single crystal semiconductor (e.g., silicon); a wafer fixing/positioning stage (4) wherein when it is assumed that the wafer surface is partitioned by a lattice having an interval d, and that the wavelength of the X-ray from the incident device is λ, an angle that the X-ray and the wafer surface form is ϑ, and an arbitrary integer is n, the stage (4) is adapted to fix the crystal orientation of the wafer so as to satisfy the condition of "2d sin ϑ ≠ nλ", and to allow sample points to which X-ray is incident to be subjected to positioning by a horizontal movement; and analyzing device (5,6) for measuring a light quantity of a fluorescent X-ray generated as the result of the fact that the incident X-ray excites atoms at the wafer surface to analyze a quantity of the metal impurity attached on the wafer surface under the condition that the Bragg reflection causing measurement noises does not take place.