Edwin,
I found those BGA and CBGA papers I mentioned.  Both are from Motorola.  The
first one has some very good hands-on advice on using CBGA and the second
has some good in-depth technical information on CBGA solder joint
reliability.  Our company does subcontract ball attach, CBGA reballing and
solder column attach.  We do not do board assembly so I am probably not the
right one to answer all of your questions.  These are both excellent papers
and you should find most of the answers you are looking for here.

BGA Assembly Process and Rework
http://www.mot.com/SPS/PowerPC/teksupport/teklibrary/papers/BGA_AssemblyRewo
rk.pdf

The C4/Ceramic-Ball-Grid Array Interconnect Technology
http://www.mot.com/SPS/PowerPC/teksupport/teklibrary/papers/603604CBGAinterc
onnect.pdf

In order to view these *.pdf files you may need to download a copy of Adobe
Acrobat Reader 3.0.
Follow the link below for a free copy:
http://www.adobe.com/prodindex/acrobat/readstep.html
or (in case they move it)
http://www.adobe.com

Hope this helps

Russ Winslow
Winslow Automation & Six Sigma


-----Original Message-----
From: Russ Winslow <[log in to unmask]>
To: Edwin Maximo <[log in to unmask]>; [log in to unmask] <[log in to unmask]>
Date: Friday, October 02, 1998 11:35 AM
Subject: Re: [TN] Types of BGAs


>The main difference from a component perspective is that most PBGA's have
>solder balls which are .030 inch diameter and are made up of Sn63 Pb37 (aka
>"eutectic solder").  The common Ceramic BGA's have solder balls which are
>.035 inch diameter and made up of Sn10 Pb90 (aka "high lead solder").  The
>high lead solder balls are attached to the component with Sn63 Pb37 or a 2%
>silver bearing version of the same.
>
>Because of the high lead balls, the ceramic bga's are not as forgiving as
>the PBGA's when it comes to self alignment.
>
>Since the high lead balls do not reflow in the process, the standoff of
.035
>inches is maintained regardless of the weight of the package.  The key
>reason behind the high lead solder balls is the increased standoff and the
>natural ductility of the high lead material which helps reduce joint strain
>which comes from mounting a low thermal expansion ceramic on a high thermal
>expansion FR4 board.
>Motorola has published some good papers on CBGA.  One of the papers I have
>seen goes into detail as to how much solder paste (in cubic mils) is
>required for a proper joint.  If I can find this paper on Motorola's web
>site I will post a link on TechNet.
>
>Hope this helps
>
>Russ Winslow
>[log in to unmask]
>
>
>-----Original Message-----
>From: Edwin Maximo <[log in to unmask]>
>To: [log in to unmask] <[log in to unmask]>
>Date: Thursday, October 01, 1998 7:30 PM
>Subject: [TN] Types of BGAs
>
>
>Hi all,
>        I'm doing some research regarding BGA.Can someone tell me what's
the
>main difference between a Plastic BGA from a Ceramic BGA (except for
>their substrate). How are they placed in PCBs, and what
>considerations are involved in it. Are there any internet sites where
>I can have some information about this topic.  Any information will
>be appreciated. Thanks
>
>
>
>Regards,
>Edwin Maximo
>Value Engineer
>Electronic Assemblies Inc. Phils.
>email: [log in to unmask]

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