0.4mm pitch BGA

[ZeroResistance]

Hi,
First time using a BGA, I have a 0.4mm pitch WLP package, 7 rows and 7 cols, The recommended pcb pad size for this is 0.25mm.

Maxim has shown how to route this with 3 layers (image attached).

My question is, this would require vias directly on the pads correct? so wouldn't the solder get sucked through the via hole during reflow causing a unreliable joint?
Are these vias of a special kind?, I mean these don't seem to be the regular thru hole vias are there of the blind buried type?

I was thinking of sending this to JLCPCB for board manufacture, but looks like their minimum via diameter is 0.45mm, so this seems to be beyond their capabilities, I have heard of Multech PCB too but never had any reviews of them, does anyone here gotten boards from Multech?

[dmills]

0.4mm is generally via in pad, filled and plated.

EXPENSIVE in prototype quantities, and somewhat specialist, avoid if you can, otherwise someone like Wurths prototype shop can do this for you.

[ZeroResistance]

0.4mm is generally via in pad, filled and plated.

EXPENSIVE in prototype quantities, and somewhat specialist, avoid if you can, otherwise someone like Wurths prototype shop can do this for you.

Thanks for your feedback, I'll stick to QFN for now.
Are these the blind / buried kind of vias?
I'd like to know what cost am I looking at for the 0.4mm via in pad PCB?

[aix]

I got curious and played with PCBWay's quotation system.  It seems that four-layer boards with vias-in-pad start at around US$365 + postage.

Also: https://www.pcbway.com/pcb_prototype/PCB_Via_in_Pad.html

[ZeroResistance]

I got curious and played with PCBWay's quotation system.  It seems that four-layer boards with vias-in-pad start at around US$365 + postage.

Also: https://www.pcbway.com/pcb_prototype/PCB_Via_in_Pad.html

Thanks for the info, that's indeed very expensive !