During fabrication, the creation of PTHs, etching process, and drilling are responsible for the contamination. Ionic contamination may occur during PCB fabrication and assembly processes. How do we handle circuit boards in the production line is also a major cause of ionic contamination in a PCB. During assembly, the components also carry various ionic/conductive contaminants along with cutting oils/fluids, biocides, and corrosion preventatives. These ionic residues have a zero net charge (the composition of positive cations and negative anions) and become charged when a PCB passes through multiple fabrication processes. These residues can be plastic, metal, and fiberglass granules, including salts, oils, and dust. Ionic contamination issues arise due to the ionic residues left behind during PCB fabrication and assembly processes. In this blog post, we will be discussing ionic contamination only. To maintain a quality manufacturing process, it is very important to identify and control them. On the other hand, ionic contaminants can be salts, organic/inorganic acids, flux activators, and plating chemistries. They don’t have conductive properties to remain on the PCB surface after PCB assembly. Non-ionic residues are oils, resin, and grease. Contaminants can be ionic and non-ionic residues. The production of circuit boards includes at least 20 chemical processes, and most of them involve extensive use of ionic matter. The growing use of PCBs in harsh environments, specifically in safety-critical applications, requires adequate electrochemical reliability to control ionic contamination. The ionic contamination analysis for any PCB should be done under the set IPC standards. Ionic contamination testing is performed through ROSE and ion chromatography tests. To ensure reliability and avoid rework and late life cycle failures, the PCBs are tested for ionic contamination. If not treated properly, ionic contamination can cause PCB corrosion, electromechanical migration (ECM), dendrite formation, and parasitic leakage. What can be more problematic than seeing your expensive PCB not performing as intended? What would you do if your expensive circuit board failed in the production line even after accurate prototyping and thorough testing? One of the common reasons for PCB failure is ionic contamination due to its exposure to dust, moisture, and the environment. RLC Resonant Frequency and Impedance Calculator.Bandwidth Rise Time and Critical Length Calculator.Transmission Line Reflection Calculator.Trace Width and Current Capacity Calculator.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |