Via in pad on an 0201 part?

[daqq]

Hello,

I'm dealing with a fairly dense board and it would help me to use vias in pads on 0201 capacitors as shown below:

Pretty much a 0.5mm via with a 0.25mm hole sticking out of the 0201 pads.

I don't work as much with 0201 components, so I would like to ask you whether this will cause any manufacturing issues? The vias are through hole, type VII, so filled and capped. There may be a small dimple, but not too deep.

I am however worried about thermal issues when soldering.

Is this an okay thing to do, or shall I use a different solution? If not, what about using microvias in the 0201 pad? Would using 0402 parts be okay in this situation (0.5mm through vias)?

Thanks!

[mtwieg]

It certainly can be done (so long as the vias are properly overplated, see IPC-6012). There are a lot of factors besides layout that can contribute to tombstoning (component placement, reflow profile, paste print quality, component height, etc), and if all of those are done well you can often get away with murder on the layout. If you're working with a good CM which will profile the boards before real assembly (i.e. not JLCPCB), I wouldn't worry much. Otherwise, I would at least avoid vias directly to large inner planes, and would try to "balance" things by having VIP on both leads. I'm assuming you're at least using blind vias, otherwise you might have trouble routing these traces...

[electron_plumber]

I wouldn't place vias of that size under 0201's due to the asymmetry it creates in the copper.

Having said that, I've placed microvias under 0201's many times in mass production with no issues. They're small enough to center in the pads without violating minimum solder mask sliver design rules. Obviously, you'll want the vias plated over.

[daqq]

Thanks! So, it's a "Yes, but..." kinda thing. I'll probably use 0402s then, they should work just fine. Gonna take up more space and have a bit less capacitors, but it'll work.

[Whales]

Can you always put a via on both pads rather than just one?  That would help the thermal & wicking symmetry.

[daqq]

Can you always put a via on both pads rather than just one?  That would help the thermal & wicking symmetry.

On most I can, but internally (or externally) they'll be connected to a plane. There's a ground plane on the inside and outside and power planes on the inside.