Abstract
By the trends of electronic package to be more integrative, the fine Cu trace pitch of organic PCB is required to be a robust design. In this study, the short circuit failure mechanism of PCB with a Cl element under the Temperature humidity bias test (<TEX>$85^{\circ}C$</TEX>/85%RH/3.5V) was examined by micro-structural study. A focused ion beam (FIB) and an electron probe micro analysis (EPMA) were used to polish the cross sections to reveal details of the microstructure of the failure mode. It is found that <TEX>$CuCl_x$</TEX> were formed and grown on Cu trace during the <TEX>$170^{\circ}C$</TEX>/3hrs and that <TEX>$CuCl_x$</TEX> was decomposed into Cu dendrite and <TEX>$Cl_2$</TEX> gas during the <TEX>$85^{\circ}C$</TEX>/85%RH/3.5V. It is suggested that Cu dendrites formed on Cu trace lead to a short circuit failure between a pair of Cu traces.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
