Hello ; Could you please explain more about what do you mean by (traces below the micro-controller). An image that shows these traces will help more to understand your idea, kindly make a picture of these traces and post it in your next comment. If your mean tracks, then yes it is possible to assemble the part as long as it follows the design rules which need to respect the JLCPCB capabilities as well. Thank you.

thanks for your quick reply, i meant something like this (just a random example)

one more question please: how do i know if my pcb complies with jlcpcb capabilities? Do i get a note after i upload the gerber, pick and place and bom? Or does jlcpcb send me an e-mail after my online-order?

@Georgschmied, Traces under devices is ok.

@andyfierman thank you Andy :) @Georgschmied Hello ; As I mentioned in my first comment, it is all OK to create tracks (traces) beneath components outline and it can be producedn and assembled by JLCPCB. Make sure that you are respecting the JLCPCB capabilities while making your design by setting the design rules regarding the JLCPCB capabilities :)  Here is the link for the JLCPCB PCB capabilities : [https://jlcpcb.com/capabilities/Capabilities](https://jlcpcb.com/capabilities/Capabilities) Here is the link for the JLCPCB SMT Assembly capabilities : [https://jlcpcb.com/smt-assembly](https://jlcpcb.com/smt-assembly) For further explanation, just let us know here :) Good luck

thanks for your reply, i know this already how to set design rules and jlcpcb capabilities, but my question was, what if i misunderstand something or overlook something and upload a file that cant actually be produced? do i get a note from jlcpcb that it cannot be produced or what happens?

@Georgschmied While preparing the production data, our engineers will inform you by Email once they discover a non-compatible design or suspicious things in your design. Please check your design before generating the related GERBER files to make sure that you are not missing anything.

ok thanks, of course i will check it thoroughly