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To:	geda-user AT delorie DOT com
Subject:	Re: [geda-user] tented vias in center pad of QFN?
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Date:	Sat, 10 Feb 2018 01:30:20 +0200
From:	"Anton Dubniak (twister AT tfsoft DOT org DOT ua) [via geda-user AT delorie DOT com]" <geda-user AT delorie DOT com>
Organization:	TFSoft
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John Griessen (john AT ecosensory DOT com) [via geda-user AT delorie DOT com] wrote 
2018-02-10 00:57:
> Hi,  Does a via in the soldered area of a center pad of a QFN work
> well with solder mask on the back covering the holes?
> Or, do they need to be open?

They should not be tented, as the trapped air will prevent the tension 
forces to do its job and solder will not be sucked inside the vias, 
which, in turn, will not result in a good thermal contact.

Once I forgot about solder mask check in a similar situation, but the 
manufacturer's CAM operator was kind enough to fix this issue in place 
(by editing the gerbers) and notified me about it.

-- 
Best regards,
Anton Dubniak (twister AT tfsoft DOT org DOT ua)

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