To the group:

I think that our industry "shot itself in the foot" when we all agreed
to define "thin copper (less than xx% of required thickness) as a
"VOID".  The criteria that we established, was that if we found a thin
spot (void) in a microsection, then we would 100% visually inspect the
lot of boards for voids.  Maybe its my advancing age and loss of visual
acuity, but when I look into a hole in a board, even under the best
scopes available, I cannot determine if there are areas of the hole wall
that have .0007" thick copper (which is a void) from the rest of the
hole wall that has .001" minimum thickness copper plating, and meets the
specifications.  However, even with my bad eyes, I can see a void in a
hole that is a "complete absence" of the required materials, be it
copper plating, or final finish material.(Ni/Au, SnPb, etc)  I think
that logic would require us to define voids as a complete absence of
material, in keeping with Merriam Webster's definitions.  This is the
criteria we use when we are looking at "laminate voids" "soldermask
voids", or any of the myriad uses of the word void.  A "thin spot" in
copper should never have been considered as a "void".  Personal
opinion---everybody's got one.

Dennis J. Cantwell
R & D Liaison
Printed Circuits, Inc.
1200 West 96th Street
Minneapolis, MN 55431-2699
952-888-7900
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-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Reed,
Randy
Sent: Wednesday, August 10, 2005 10:45 AM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Request for Plating Definitions for IPC-T-50

I offer the following for consideration for the definition of plating
void.

Plating Void: An isolated thinning of the copper plating thickness that
is
less than the minimum copper thickness limit.

The reason I offer this alternate definition is the absence of plating
does
not make sense in the following scenario.

"The customer specification states the minimum copper plate thickness is
0.0007" and the acceptable plating void quantity is 1 maximum.  On the
microsection evaluated there is an isolated location where the copper
thickness thinned to 0.0001".  This sample is unacceptable to the copper
thickness limit and acceptable to the plating void limit.  The
reliability
of the sample is no different."

Randy Reed
Merix Corporation

-----Original Message-----
From: IPC-600-6012 [mailto:[log in to unmask]] On Behalf Of Susan
Mansilla
Sent: Wednesday, August 10, 2005 6:09 AM
To: [log in to unmask]
Subject: Re: [IPC-600-6012] Request for Plating Definitions for IPC-T-50

Greetings to All
I would offer the following definitions

Plating Void - Complete Absence of Plating.  Some specifications have a
minimum value that is considered to be a void in lieu of complete
absence of
plating.

Plating Fold - Line that is visible after microetch in hole wall copper
plating where the plating on two sides of a void plate up and eventually
touch.

Tangency - In a vertical microsection, the extreme degree of
misregistration
where there is any evidence of the original inner layer foil visible on
one
side of the hole.  No evidence of original innner layer foil would be
considered to be misregistration to the point of breakout.

Susan Mansilla
Technical Director
Robisan Laboratory, Inc
6502 E 21st Street
Indianapolis, IN 46219

317-353-6249 phone
317-917-2379 fax

www.robisan.com