Correct. 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Franklin D Asbell
Sent: Tuesday, September 26, 2006 12:19 PM
To: [log in to unmask]
Subject: Re: [TN] Over-developed Soldermask

If there is peeling/flaking after they have performed all cure
cycles/steps then I would suspect the reliability of the mask.

Under/over developing in itself is not a major concern in my opinion;
however, if it has removed so much of the mask in fine areas where it
affects adherence of the mask to the board then this leaves the
possibility of mask lifting at some point in the future, this lifting
mask may potentially entrap contaminates thus presenting additional
reliability issues.

Franklin

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Kevin Glidden
Sent: Tuesday, September 26, 2006 11:26 AM
To: [log in to unmask]
Subject: [TN] Over-developed Soldermask

Question for the PCB fabricators...

One of our PCB suppliers is asking us to accept PCBs with a "minor"
issue.
The problem is described as this: The panels were under-developed and
some residual solder mask was left over.  To eliminate this, the panels
were put through a second pass to ensure all residual solder mask was
removed.  The result is some overdevelopment of the solder mask.  Then,
this apparently resulted in an "undercut" along the demarcation lines.
They say during a tape test, very small traces of mask from the
undercuts comes off.  The mask
is still present between all features and is adhered to the PCB.   But,
it
is over-developed and has undercuts.  They say that while it does not
pass the tape adhesion test, it is of no detriment to the PCB quality or
performance.

My question is if over-developed soldermask maintains the same
properties as normally developed soldermask?  When I asked about this,
they said the properties of the mask are determined by the initial
(pre-developing) cure and the final (post-developing cure), and the
over-development does not affect the properties.  True?

In case "it depends", these PCBs are used in avionics power supplies.

Thanks in advance!

Kevin

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