HEAVY METAL POLLUTION MONITOR FOR SI WAFER

摘要

PURPOSE:To monitor the existence of heavy metal pollution on the surface of an Si wafer used for the manufacture of highly integrated memory, etc., by a method wherein the surface of a specimen to be measured is irradiated with electron beams making specific low angle so as to detect the fluorescent X-rays excited from the specimen surface for performing the quantitative analysis of the metals. CONSTITUTION:When the set up electron beams are entered making an incident angle, fluorescent X-rays are emitted. Furthermore, when these fluorescent X-rays hit against the window of an fluorescent X-ray detector 5, a current is generated from Li doped Si. This current is amplified by a pre-amplifier 9 and an amplifier 8 further making digital signals A-D converted by an A-D converter 7. Moreover, the intensities of these digital signals are counted up per respective wave lengths of the fluorescent X-rays. Through these procedures, any pollutant metals are quantitatively analyzed by a computer 10 based on the counted up results so as to output the analysis results by an output means 12. On the other hand, this computer 10 is connected to a stepper motor controller 11 through an RS-232C to be an interface so as to control the transmission and reception of the digital signals.