FEDEVEL
Platform forum

Gabriele Marocco , 11-15-2025, 04:07 PM

Hy, Soon I will have to fanout a microcontroller (STM32G4A1REI6) which due to the board limited space is a 0.5mm pitch BGA with 64 pins (the microcontroller pins that are used are roughly 70% of the available pins).

I have looked at some papers but I have still doubts since it is my first project involving a fine pitch BGA component . I have searched also for some reference boards containing a 0.5mm BGA component but I can only find designs
with 1mm and 0.8mm BGA.

I ask which fanout strategy is better to use in order to optimize PCB production and PCB assembly costs. For example do you recommend the use of via-in-pad?

I will plan to use 6 layers. and to route the signals mainly in inner layer 2 and Inner layer 3. In order to connect the signals I am thinking of using microvias (for example a microvia connecting the TOP layer with inner1layer and the another microvia connecting inner layer 1 with inner layer 2. Is it feasible to use microvias with 0.1mm hole diameter and 0.3mm pad?

Another question: do you recommend some PCB manufacturers that can produce quite easily these kind of PCBs?
Thanks in advance

QDrives , 11-15-2025, 04:48 PM

https://www.we-online.com/files/pdf1/design-rules-poster-hdi-microvia-cbt-en.pdf
or more here: https://www.we-online.com/en/products/printed-circuit-boards/hdi-microvia#i5427

Gabriele Marocco , 11-15-2025, 05:50 PM

Thanks!