Hello robertferanec ,
I am concerned with solder mask expansion on Vias and SMD pads. I understand that SMD pads should have some mask expansion to make better solder contact to BGA pads. But, vias dont need anything soldered onto. So, tenting all vias with no expansion makes sense and Ive seen you use tented for top and bottom for TH vias. However, some TH vias like in the RAM location and micro vias have -10mm expansion. And buried vias like at the T topology breakout, the vias solder mask expansion is specified from the rules. Why not make all vias tented with solder mask expansion set at 0 in the rules? Why are they different?
TH vias under RAM with -10mm solder expanison mask:

Mciro Vias with -10mm solder expanison mask:

Buried vias L3 - L10, solder mask expansion defined from rules:
I am concerned with solder mask expansion on Vias and SMD pads. I understand that SMD pads should have some mask expansion to make better solder contact to BGA pads. But, vias dont need anything soldered onto. So, tenting all vias with no expansion makes sense and Ive seen you use tented for top and bottom for TH vias. However, some TH vias like in the RAM location and micro vias have -10mm expansion. And buried vias like at the T topology breakout, the vias solder mask expansion is specified from the rules. Why not make all vias tented with solder mask expansion set at 0 in the rules? Why are they different?
TH vias under RAM with -10mm solder expanison mask:
Mciro Vias with -10mm solder expanison mask:
Buried vias L3 - L10, solder mask expansion defined from rules:
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