Hello,
I'm assuming you are not familiar with creating library parts so this is the place to start. I wrote a tutorial on this a few years ago so if you aren't up to speed with creating parts yet this is a reasonable starting point.
https://www.element14.com/community/docs/DOC-88188/l/eagle-tutorial-series
When I wrote this the current version of EAGLE didn't have the package generator which is available in more recent versions of EAGLE. For the 0.8mm pitch 144-ball BGA of the part you are wanting to create you can create this easily with the package generator. If it were a finer pitch part there would be extra I would recommend (due to limitations of the auto generated mask apertures) but for this part it'll be fine. You don't need a managed library to create this, stick with proper libraries.
Once you have the part then you can get it into your design and start routing it out. The first thing I would say is forget about the BGA autorouter altogether, it's not a substitute for manually routing out the BGA and doesn't perform well. I did actually write a blog post about using it a while back but my conclusion was that whilst I would coax it into doing something ok in the limited test scenario, I could do much better by hand more quickly. If you want to read that blog you can find it here:
https://www.element14.com/community/community/eagle/blog/2017/08/29/eagle-v8-taming-the-bga-router
In the comments below the blog there are some additional discussions with further improved attempts at the breakout so take a look through there too to get some idea of how to break out a BGA.
Now, I've done quite a few large BGA's recently and the general workflow I have used for through via breakout is as follows:
1) Configure the board stackup for the number of layers.
2) Carefully plan power/ground layers.
3) Set up your widths/clearances/min drills in the DRC.
4) Configure the via setting for the required via for your BGA breakout.
5) Use the fanout tool to break out the BGA to vias.
6) Place decoupling caps underneath the part. At this point you might need to nudge vias or change some to blind/buried vias to allow space to fit the decoupling caps. **
7) Route out critical signals, e.g. clocks, SERDES, impedance controlled / length matched traces, etc
8) Route out the rest of the signals.
** My most recent design was a large 900-ball 1mm pitch BGA. I did this entirely with through vias with 0402 decoupling caps underneath. I was able to fit these because I use rounded pads by default in my library parts so the caps didn't have pointy pad corners clashing with vias underneath the BGA.
There is more to it that given above, you often have to make trade-offs to get things in but this will come with experience. The best thing you can do is give it a go and see how you get on and if you get stuck feel free to ask questions.
Best Regards,
Rachael
