STM32 UFBGA vias layout best solution

vincent239955_st · ‎2016-04-25

Posted on April 25, 2016 at 16:22

I,

I'm using Altium designer and I'm rooting a UFBGA64 (STM32F098RC).

BGA pad dimensions are the following:Pitch: 0.5mm/Dpad:0.280/Dsm 0.370mm.

I would like to know what is the best solution to place vias for this UFBGA64 ? And which are the recommended dimensions ?

Many thanks.

Tesla DeLorean · ‎2016-04-25

Posted on April 25, 2016 at 18:36

I don't do the PCB CAD stuff, but in my experience if you use via-in-pad, you need to make sure you fill and planerize them so you get uniform soldering across all pads.

Tips, Buy me a coffee, or three.. PayPal Venmo
Up vote any posts that you find helpful, it shows what's working..

mark239955_stm1 · ‎2016-04-25

Posted on April 26, 2016 at 05:40

You should discuss this with whoever will be loading the BGA's onto the PCB's. They will know their own capabilities.

stm32forum · ‎2016-04-26

Posted on April 26, 2016 at 12:04

0.5mm Bga is not that difficult.

You can choose for fanout, dog bone or via in pad.

It depends on what's the allowed board price.

Via in pad is the most expencive one because the via's need to be filled.

Dog bone is a nice solution, however it depends on your board house if they can drill that small.

Have a look at

http://www.evertdekker.com/Joomla/images/stories/fotoupload/20120726_microbga.pdf

for some design tips, from page 18 is 0.5mm bga.

vincent239955_st · ‎2016-04-26

Posted on April 26, 2016 at 16:45

Many thanks for these informations.

We will very probably choose the via in pad solution, we already have 0.1mm laser drill on the previous version.

For a 148.75mm dielectric thickness, a 0.125mm laser drill seems good.