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.
Recently, our company started a new project, and the R&D team has been pushing PCB layout requirements to the extreme. As PCBs size get smaller, the solder mask (S/M) design must also shrink accordingly. However, our current PCB manufacturers struggle to meet these tighter tolerances, and those who can do it demand a price increase. The moment extra cost is mentioned, everyone hesitates and sticks with the existing PCB suppliers, resulting in solder mask misalignment that extends beyond the pads.
