Using same pattern for QFN/QFP -- mask/paste issue...

Making PCB Layouts, Manual routing, Auto-routing, Copper pouring, Updating from Schematic, Manufacturing Output
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Rich T
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Joined: 22 Nov 2022, 06:12

Using same pattern for QFN/QFP -- mask/paste issue...

#1 Post by Rich T » 12 Apr 2023, 11:10

Hi,

I have designed my board to use either QFN or QFN (supplies are limited as production ramps up), by having the QFN pattern "inside" the QFP pattern. This all works and the 64 "pads" just look extra long.

Up to now, I have had solder paste on the whole elongated pad, but now I want to just put the paste on the QFN portion of the pad, and cover the QFP portion of the pad with a solder mask.

In pattern editor this all seems to work -- I have two pads for each pin (like 1@, 2@, ...64@) and they are connected. I can ask the outer pads to "tent" all similar pads, and everything works -- in pattern editor.

When I turn on just the paste and mask layers, I can see paste on the inner pads and mask on the outer pads, exactly like I expect.

The problem is by the time I go thru component editor, schematic editor, and pcb layout, now the two pads per pin get the same "paste and no mask" layers.

Would you have any suggestion for how to make pcb layout show the same layers as pattern editor?

(If I do something like change the silkscreen of the pattern, it propagates thru perfectly all the way to pcb layout -- but changing the mask/paste settings somehow gets merged for the two pads per pin.)

Thanks for any suggestion!

-- Rich

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