X-Authentication-Warning:	delorie.com: mail set sender to geda-user-bounces using -f
X-Recipient:	geda-user AT delorie DOT com
Date:	Thu, 17 Jul 2014 02:11:32 +0200
From:	Bernd Walter <ticso AT cicely7 DOT cicely DOT de>
To:	geda-user AT delorie DOT com
Subject:	Re: [geda-user] opper ring flag for vias and pins
Message-ID:	<20140717001132.GE59609@cicely7.cicely.de>
References:	<20140715173322 DOT GC56151 AT cicely7 DOT cicely DOT de> <53C56BEB DOT 7030701 AT sonic DOT net> <20140715185832 DOT GA56618 AT cicely7 DOT cicely DOT de> <70a6b8dbb9130d0db9bca203a46bb332 AT cam DOT ac DOT uk> <201407161822 DOT s6GIMoKA006073 AT envy DOT delorie DOT com>
Mime-Version:	1.0
In-Reply-To:	<201407161822.s6GIMoKA006073@envy.delorie.com>
X-Operating-System:	FreeBSD cicely7.cicely.de 7.0-STABLE i386
User-Agent:	Mutt/1.5.11
X-Spam-Status:	No, score=-2.9 required=5.0 tests=ALL_TRUSTED=-1,BAYES_00=-1.9,T_RP_MATCHES_RCVD=-0.01 autolearn=ham version=3.3.0
X-Spam-Checker-Version:	SpamAssassin 3.3.0 (2010-01-18) on spamd.cicely.de
Reply-To:	geda-user AT delorie DOT com
Errors-To:	nobody AT delorie DOT com
X-Mailing-List:	geda-user AT delorie DOT com
X-Unsubscribes-To:	listserv AT delorie DOT com

On Wed, Jul 16, 2014 at 02:22:50PM -0400, DJ Delorie wrote:
> 
> > You need to be able to remove inner layer pad annuli completely for 
> > signal integrity reasons on some high-speed lines.
> 
> Aren't there manufacturability issues if you do that?  I.e. voids
> where the copper should be, causing breaks in the barrel?

Why should there be any?
I can't tell for sure, but when the holes are drilled and plated after
stacking then such a plated hole without inside annular rings should
be just the same as they would be with a standard 2-layer board.
But I just investigated some very high densisty CPU boards I had
within reach and all of them used microvias, but had at least rings
on the outside layers of all vias.
I probably should ask a board manufacturer about their opinions.

-- 
B.Walter <bernd AT bwct DOT de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.

- Raw text -