As the electronics industry makes use of ever thinner coatings, manufacturers increase their demands on measuring technologies to provide reliable parameters for product monitoring. One example is the Au/Pd/Ni/Cu/printed circuit board system with coating thicknesses for Au and Pd of just a few nm. For monitoring the quality of these coating systems, X-ray fluorescence XRF analysers have established themselves as the measurement method of choice.
The thinner the coatings, the more important it becomes to select a suitable detector and the SDD's (Silicon Drift Detector) repeatability precision allows for such reliable measurement. The trueness is also better for instruments with SDD because the high energy resolution of the usable signal is less susceptible to influence from the background or adjacent fluorescence lines.
Proper handling of the fluorescence signal generated by the substrate material is also more important with thinner coatings. While a general subtraction of the background signal does improve the repeatability precision, it can also introduce errors into the results. The evaluation software WinFTM® therefore explicitly allows the composition of the substrate material to be taken into account with every measurement.
The X-ray fluorescence XRF analyser options for measuring Au/Pd coatings on printed circuit boards are the FISCHERSCOPE® X-RAY XDL® with proportional counter tube, XDAL® with PIN detector, or XDV®-SDD with SDD detector; all available through Fischer's UK office - Fischer Instrumentation (GB) Ltd. 01590 684100.