Observation of the Gold Plated Surface of Flexible Printed Circuits (FPC) by Electron Probe X-ray Micro-Analyzer (EPMA) .

Recently fine line Flexible Printed Circuits (FPC) are used in many applications such as Thermal Head Printers and Faximille. In these applications very precise control of plating thickness is required and leads us to difficult problem both in design and in measurment of plating thickness.The conventional β-ray method and Fluoro X-ray method are not sufficient to answer the above requirement. The Electron-Probe X-ray Micro Analyzer (EPMA) is recently developped surface measuring method which is especially suitable for these purposes.We applied this new technique to analyze the degrading problem in gold plated surface of FPC. Also the authors summarized the circuit resistivity effect on plating thickness control.