Investigation of measuring hazardous substances in printed circuit boards using the micro-focus X-ray fluorescence screening

TL;DR

This study demonstrates that micro-focus X-ray fluorescence screening effectively detects hazardous substances like Pb and Br in printed circuit boards, providing a quick and simple method for chemical analysis in the electronics industry.

Contribution

The paper introduces a practical micro-XRF system for analyzing hazardous substances in PCBs, highlighting its effectiveness and simplicity compared to traditional methods.

Findings

Hazardous substances such as Pb and Br are detected in PCB samples.

Micro-XRF screening provides quick qualitative analysis of hazardous substances.

Statistical data on substance concentrations are presented.

Abstract

Printed circuit boards (PCBs) are widely used in most electrical and electronic equipments or products. Hazardous substances such as Pb, Hg, Cd, etc, can be present in high concentrations in PCBs and the degradation and release of these substances poses a huge threat to humans and the environment. To investigation the chemical composition of PCBs in domestic market of China, a practical micro-focus X-ray fluorescence system is setup to make the elements analysis, especially for detecting hazardous substances. Collimator is adopted to focus the X-ray emitted from X-ray tube. BRUKER X-ray detector with proportional counter is used to detect the emitted fluorescence from the PCB samples. Both single layer PCB samples and double layers PCB samples made of epoxy glass fiber are purchased from the domestic market of China. Besides, a MC55 wireless communication module made by SIEMENS in Germany is used as the reference material. Experimental results from the fluorescence spectrums of the testing points of PCB samples show that, hazardous substances, mainly Pb and Br, are detected from the welding pads and substrates. In addition, statistical data about the average relatively amount of the main substances in testing points are also illustrated. It is verified that micro-XRF screening offers a simple and quick qualitative measurement of hazardous substances in PCBs.