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While layouting in Kicad I've encountered a problem to place a via for BGA component. I design 4 layers board, I have 20-pin BGA component on the front, and I want to place vias for it on the back side. The problem is, that the tool doesn't allow to place via inside the BGA component rectangle. In the attached picture you can see the BGA footprint in the center and the via is from the left side. There it placed without problems, but I cannot drag it into the area between the BGA component pads.

Thank you in advance. enter image description here

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    \$\begingroup\$ I'm not where I can fire up KiCAD and check, but I think the red rings around the bga pads are exclusion areas or something similar. You would have to change that in order to allow a via between the pads. \$\endgroup\$
    – JRE
    Commented Jun 10, 2016 at 9:24
  • \$\begingroup\$ I agree with JRE, this sounds like a design rule problem (I know Altium has a rule for vias under pads and a rule for pad to hole spacing, I imagine KiCad's got something similar). \$\endgroup\$
    – Sam
    Commented Jun 10, 2016 at 9:35
  • \$\begingroup\$ @JRE is right. You will need to use a footprint where the pads have less "security margin" around them. Which brings me to the question: What kind of footprint is that? It seems to be of low quality; overlapping keep-out areas obviously would make it impossible to use that BGA footprint. If it's yours, that's easy to fix (just remove the size of the keepout are an the footprint editor). \$\endgroup\$
    – Marcus Müller
    Commented Jun 10, 2016 at 11:16
  • \$\begingroup\$ @MarcusMüller: Why not make that an answer? I wasn't certain about the problem, but it sounds like you know more about KiCAD than I do. I only use KiCAD occasionally, and never had anything to do with BGAs. \$\endgroup\$
    – JRE
    Commented Jun 10, 2016 at 11:35

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As @JRE pointed out, these red circles are a keepout area for signals not belonging to the pad's net.

You will need to use a footprint where the pads have less "security margin" around the pads. You can adjust that under Tools->Design Rules by reducing the "Clearance".

Which brings me to the question: What kind of footprint is that? It doesn't have a component outline...

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