Good Day

I used internal power planes for the first time (Altium), and I now want to generate fabrication outputs in the form of Gerbers.

The gerber below illustrates my internal GND plane, to avoid confusion with the fab house I would like to invert the gerber? Currently the voids are supposed to be copper and the copper is supposed to be voids? It looks to me like the whole gerber should be inverted.

Where do I change the settings for this?

Thank you!

Altium Internal Power Plane Inverted


Power planes are always created as negatives. You have a couple of options:

  1. Specify to your manufacturer that this layer is a negative. Many manufacturers will ask you the polarity of the layers.
  2. (My personal preference) Instead of using planes, use polygon pours. This way there is no doubt, and it's clear where the copper is.

The choice is ultimately up to you as a designer, but I tend to find #2 easier to do and it doesn't rely on having smart people at the board house.

  • 1
    \$\begingroup\$ Thank you for the answer. Yes the last thing I want to rely on is having 'smart' people catch stuff like this at the fab house. Someone also pointed out to me that there is no error checking on power planes, leaving copper slivers that are smaller than minimum width and stuff like that that might compromise connectivity. They also pointed out that the only benefit of power planes are the built in impedance calculator. \$\endgroup\$
    – AJBotha
    Jan 24 '16 at 15:06
  • 1
    \$\begingroup\$ Using a negative layer for a power plane also substantially reduces the size of your gerber files. This was a big deal back in the day when gerbers were transferred over 14.4 kbd modems or as stacks of floppy disks in a FedEx envelope. Any fab shop anywhere should be able to deal with negative layers. \$\endgroup\$
    – The Photon
    Jan 24 '16 at 16:54
  • 1
    \$\begingroup\$ Remember, they already have to deal with the fact that half your layers have to be left-to-right mirrored before imaging on the panel. If they aren't paying attention to this stuff, they won't stay in business long. \$\endgroup\$
    – The Photon
    Jan 24 '16 at 16:56

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