>From the EMPF Helpline in Indianapolis, prepared by Bill Goers:

Generic Guidelines are OK, but each situation is going to require knowledge
of some of the reasons why behind the generic answers.  With that
said....here we go

1.  Process Control.
        Inspect the print
        Inspect the Place
        Inspect/Monitor the oven (real time)

        DO NOT Inspect the final product.

2.  Reflow.
        Instrument the BGA board in such a way so that you are monitoring
the temperature of the center of the BGA in the solder joint.

3.  Design Considerations
        Design in METRIC.  The parts are in metric. (this is a minor point,
but an important one)

        Pad design is dependant on reliability wants, component type and
board fabrication

        There are very few standards for board design dimensions

4  Questions
        - what reliability are you shooting for?
        - are you going to clean?
        - what about rework?

5.  I am sure there are things I didn't talk about, but..... BGA Assembly
is no trick.  Process control is the key.

[log in to unmask]
----------
From:   Michael Hughes[SMTP:[log in to unmask]]
Sent:   Monday, 16 September , 1996 10:04 a
Subject:        BGA PROCESS GUIDELINES

I'm at Cabletron Systems, Inc. in Rochester, NH.

I saw alot of EMail on Implementation of BGA Process Technology. We're
ramping up our BGA PCB production on a product and if you have some
guidelines/checklists on BGA Process Technology, please send me an EMail on
it.

                                      Thanks,

                                      Michael Hughes
                                      Cabletron Systems, Inc.
                                      [log in to unmask]

***ALL NEW EMPF PHONE NUMBERS***

                      Jack Crawford
                  HelpLine Manager
    Electronics Mfg. Productivity Facility
         NEW--317.655.3688--NEW
               Visit our homepage at:
                http://www.empf.org


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