I am working on the new PCB Fab notice for the PCB board house, and try to come up with a good explanation of differences of the 2 terms below and try to determine which term I should use to avoid confusion:

  • 1oz copper thickness
  • 1.5 oz finished copper

Any thought or suggestion?

  • \$\begingroup\$ Is this a foil or core build? (i.e. are the outer dielectric layers pre-pregs or cores?) If they're cores and you specify 1 oz for the inner layer, it'll be obvious the top layer needs to be 1 oz plus plating. \$\endgroup\$ – The Photon Jul 16 '18 at 15:43

1.5 oz. finished copper is what you get when you start with 1.0 oz. copper (35 µm thick) and add 17.5 µm of plating to it (typical for the vias and other plated thru holes).

If you want to end up with 1.0 oz. finished copper, you need to start with 0.5 oz. copper clad stock for the outer layers.

  • \$\begingroup\$ 1.5 oz. finished copper or 52.5 µm looks very uncommon. The standard sizes are 1, 2 or 3 oz. or 35, 70 or 105 µm. \$\endgroup\$ – Uwe Jul 16 '18 at 14:58
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    \$\begingroup\$ The actual body of the question seems to be more asking for advice how to unambiguously communicate the requirement to the board house. \$\endgroup\$ – Chris Stratton Jul 16 '18 at 15:14
  • \$\begingroup\$ @ChrisStratton: That may be, but it isn't at all clear. At least, I've explained how the two terms relate to each other, allowing the OP to decide what he wants and then communicate that to the vendor. \$\endgroup\$ – Dave Tweed Jul 16 '18 at 15:41
  • \$\begingroup\$ Thanks all for all the inputs. Is that true 1.5oz finished cooper not popular for the PCB board house? \$\endgroup\$ – user126465 Jul 16 '18 at 18:23

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