Larry,

        Regarding your comments to the question of inclusion or removal
of "dead" (non functional) pads:

        Larry Campbell wrote:
>
> I'd really like to have the IPC test this out and document the
> resusts so this question can be put to rest.  Maybe they have
> already done so, but I haven't been able to find any
> documentation about it yet.
>
        There are presently 3 independent studies that are in progress to
understand the performance differences between PWB products produced
with either non-functional pads on all internal layers, or the removal of
all non functional pads.  The 3 studies are as follows:

        I.P.C.
        A combined effort between the Plated Through Via (PTV)
Reliability Task Group and the Post Separation Task Group.  The objective
of the PTV Reliability Task Group is to build PWB products which contain
3 metallization quality levels in the vias (Good, Marginal, Bad).  Half
of the test coupons were designed with non functional pads and half
without. The coupons will be exposed to accelerated stress testing to
determine if performance differences are found between the different
configurations.

        The test panels are presently being built at 3 highly reputable
PWB manufacturers, coupons should be available for testing in 2 to 3
months, results will hopefully be available late summer or in the fall.
If anyone is interested in receiving the minutes from regular conference
calls or attending the IPC task group meetings, contact Lisa Williams
([log in to unmask]) at the IPC.


        I.T.R.I.
        At the IPC winter meeting in Tempe this past weekend, the
Registration Reliability Phase 3 Test Plan proposal was discussed.  The
test plan is designed to quantify if the reliability of the interconnect
is influenced by inner layer pad breakout.  This test plan will contain
the inclusion or removal of non functional pads as a variable.  This is
an extensive study that has gained excellent insights from the first 2
reliability studies.  This latest study will be comparing 72 possible PWB
constructions combinations, half of the test coupons will be designed
with non functional pads and half without.  The formation of companies
interested in participating will likely occur at IPC Expo.  For further
information contact Diana Hempstead ([log in to unmask]) at ITRI.

        AlliedSignal Laminates Division.
        In order to characterize the performance differences for their
new PWB materials, they have developed a test plan that includes
accelerated stress testing on products that either include or remove non
functional pads on the inner layers.  The PWB's were recently
constructed, testing is due to start shortly.


        There is a lot of interest in this area of interconnect
reliability/performance, if any individual or company has reliability
data that they are willing to share, it would be much appreciated.
Those wanting more information regarding the existing testing activities
should participate with the various IPC task groups (Many hands make
light work).


        Best Regards,

        Bill Birch
        IPC PTV Reliability Task Group Chairperson.

##############################################################
TechNet Mail List 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://www.ipc.org/html/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
##############################################################