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STM32 fine-pitch BGA packages
Bob , 10-12-2025, 03:43 AM
Wanted to try routing a super small WLCSP BGA (0.4mm pitch) STM32 chip for one of my compact boards to get some more experience routing BGAs and saving board space, and don't really mind spending a bit more money on fab. I havn't found anything online for how to route these fine-pitch BGA packages (0.4 or 0.5mm pitches) and heard scary stories of Via-in-pad and BGA stuff for common hobbyist fab houses like JLCPCB/pcbway and was wondering if anyone has experience with this and whether this is a totally doable or terrible idea.
QDrives , 10-12-2025, 08:06 PM
You mean something like lase drilled micro vias in an HDI board?
Bob , 10-12-2025, 09:46 PM
im guessing WLCSP would require HDI but what about 0.5? dont really want to do HDI, how do u determine if u need HDI or not for a bga?
Robert Feranec , 10-13-2025, 09:25 AM
this may help: https://jlcpcb.com/capabilities/pcb-assembly-capabilities
Robert Feranec , 10-13-2025, 09:29 AM
0.5 is economic, 0.35 is standard PCBA, PCB manufacturing says minimum pad 0.25mm, minimum pad to pad clearance 0.15 ... looks like could be possible to manufacture and assemble 0.4mm bga. but I am not sure how to fan out the balls in middle, have not tried that with JLC - it may not be possible for 0.4
Robert Feranec , 10-13-2025, 09:35 AM
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