Where were you 8 weeks ago?  This same question came up
and answers lasted over a week!  It seems the lastest
consensus is, there is no consensus.  For as many reasons as
there were to include them, there were an equal number not too.
I've had vendors want them removed for manufacturing reasons
and stackup reasons. (You don't have annular ring problems
and you don't get the additional copper stackup on multilayer
boards vs. the stackup of reduced copper areas over the other
board.  On the other hand, the internal pads may (read that MAY)
aid in the hole plating adhesion.  We have done it both ways,
both with our knowledge and when the board vendor didn't
bother to tell us what they were doing.  We haven't seen a
difference as far as reliability is concerned.  There may be a
difference however, on the type of board you are designing (high
speed).  I think I saw once that there was an archive of this site
somewhere but I've never looked for it.  Good luck.

Larry Campbell
Supervisor, PWB
BFGoodrich, Avionics Systems

>>> Karl Sweitzer <[log in to unmask]> 05/13/98 08:27am
>>>
We typically use nonfunctional lands to improve PTH reliability for
our polyimide boards.  This is based on NHB 5300 section
3K703 and
IPC-D-275 section 5.3.2.5

On a current design, our board vendor is asking to remove them
based
on some recommendations he has heard in the industry.  We
are hesitant
to do this based on the above quoted specification.

What do you all think?
--
Karl Sweitzer                     voice: 716.47.77546
Eastman Kodak Company             pager: 716.25.33681
800 Lee Road                        fax: 716.47.77293
Rochester, NY 14650-3118         mailto:[log in to unmask]

################################################################
TechNet E-Mail Forum provided as a free service by IPC using
LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to
[log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet
################################################################
Please visit IPC web site (http://jefry.ipc.org/forum.htm) for
additional information.
For the technical support contact Dmitriy Sklyar at
[log in to unmask] or 847-509-9700 ext.311
################################################################

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
################################################################