How to make Vias to move to another PCB layer for STM32H757xI in package WLCSP156 ?

[Ronil]

Hello all, How can I make a vias for the WLCSP156 to connect my internal layers from my PCB with WLCSP156 pads? If the pad diameter is only 0.220 mm in WLCSP156 , and the minimum hole for the vias at the factories is 0.15 mm (with ring is 0.25 mm that alreyde bigger than pads in WLCSP156 ).
What is the name of the technology in this case that will allow making a transition hole with a size of 0.1 mm and make the connection between pads for WLCSP156 and the internal layers in my PCB board?

[Andrew Neil]

That would depend on what PCB design tools you use - nothing specifically to do with ST or STM32.

Best to take that up with your PCB tool supplier

[Ronil]

ST produce this chip, and I'm sure they have in mind the mechanism of how to use it.
I made a project, and made small vias, but factories do not work with such small vias