Workingbear has noticed that many people still have questions about EDX/EDS elemental analysis reports. This is the second article where he tries to provide answers based on his knowledge.
EDX (Energy-Dispersive X-ray Spectroscopy), also known as EDS, is actually an auxiliary function used in SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), and STEM (Scanning Transmission Electron Microscopy) analysis techniques.
In failure analysis reports for PCB assembly defects, we often use EDX or call EDS (Energy-Dispersive X-ray spectroscopy) for chemical elemental analysis. However, many people don’t fully understand how EDX works, and they have only a vague idea of how to interpret an EDS elemental analysis report. In most cases, after running an EDX scan and obtaining an elemental analysis, they get stuck—unsure of what to do next. The real question is: What useful information can EDX actually provide?
When we discover unknown contaminants on printed circuit boards assembly (PCBA) or electronic products, how do we determine what they are and where they come from? Do we rely on experience, or do we use scientific instruments for analysis? What methods are commonly used in the industry to detect and analyze contaminants?
In the electronic devices we use daily—such as remote controls, smartphones, refrigerators, TVs, air conditioners, and computers—there is a crucial component called the Printed Circuit Board (PCB). The name comes from the way its electrical circuits are formed, similar to early book printing. Some also refer to it as a Printed Wire Board (PWB).
A user asked: “During the SMT process, PCBs often warp or bow after going through reflow high temperature. In severe cases, this can lead to defects like insufficient solder joints or tombstoning. How can we prevent and solve this issue?”
To be honest, the reasons behind PCB warping and bowing may vary, but in the end, it all comes down to one key factor—when the stress applied to the PCB exceeds the material’s ability to withstand it. If the PCB experiences uneven stress or different areas of the board have varying resistance to stress, warping and bowing will occur.
