I have to disagree. In my experience, small holes unsymetrically masked make
it extremely difficult to get consistent rinsing and drying results thru the
ENIG and IAg processes. For ENIG boards I often ask the customer for barrel
reliefs to avoid possible skip plating / back pad issues. For IAg, moisture
remaining in the holes discolor the silver surface around the unsymetrically
masked holes. Although I have processed boards like this successfully, I
can't get consistent, repeatable results.
Just my two cents.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Alistair Murray
Sent: Tuesday, May 01, 2007 9:00 AM
To: [log in to unmask]
Subject: Re: [TN] unsymetrically masked vias


John
This is quite a common practice and is easily accomplished by a
fabricator

Regards

Alistair

Technical Manager

Artetch Circuits Ltd

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of John Foster
Sent: 01 May 2007 16:48
To: [log in to unmask]
Subject: [TN] unsymetrically masked vias

Is it problematic for a fabricator if a via

.062 board   10 mil finished via


is masked on one side and not the other?

Any input will be appreciated

Thank You
John Foster

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