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November 2001

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Subject:
From:
"<Peter George Duncan>" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Tue, 20 Nov 2001 17:03:48 +0800
Content-Type:
text/plain
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text/plain (175 lines)
Hi, Peter,

I can't help you with how to rework a micro BGA, never having dealt with
them, but I ask a question: Are you wanting to rework them just because
they have voids, or have the voids broken through the side of the balls?
Voids in themselves are not necessarily to be taken as being defects unless
they do break through.

Having had larger BGA's reworked, I can say that changing BGA's is an
expensive pain and better avoided if possible.

My tuppence worth only

Peter Duncan




                    Peter Lee
                    <ppwlee@YAHOO        To:     [log in to unmask]
                    .COM>                cc:     (bcc: DUNCAN Peter/Asst Prin Engr/ST
                    Sent by:             Aero/ST Group)
                    TechNet              Subject:     Re: [TN] BGA voids
                    <[log in to unmask]
                    ORG>


                    11/20/01
                    02:29 PM
                    Please
                    respond to
                    "TechNet
                    E-Mail
                    Forum."






How would one rework an assembly with micro BGA voiding due to several
micro vias on pad?





Rgds,


Peter





     -----Original Message-----
     From: TechNet [mailto:[log in to unmask]] On Behalf Of Brooks,Bill
     Sent: November 19, 2001 8:48 AM
     To: [log in to unmask]
     Subject: Re: [TN] AW: [TN] BGA voids





     We used to make PCB's back in the mid 1970's and used a fusing oil
     produced by Shell Oil in our Hydro-squeegee. I want to say it was some
     sort of Peanut oil... but I can't remember for sure... Those were my
     High School years... :)


     Good luck... - Bill Brooks
          -----Original Message-----
          From: David Fish [mailto:[log in to unmask]]
          Sent: Monday, November 19, 2001 11:27 AM
          To: [log in to unmask]
          Subject: Re: [TN] AW: [TN] BGA voids


          Who are suppliers of inspection quality oils [Canadian Balson??]
          the bear the heat of soldering well?
           ----- Original Message -----


           From: Bob Willis


           To: [log in to unmask]


           Sent: Monday, November 19, 2001 4:45 AM


           Subject: Re: [TN] AW: [TN] BGA voids





           The outgassin test for blowhole in printed boards was developed
           in the years gone bye after it appeared in and Italian PCB
           specification I was asked to review. After some testing I did it
           ended up in the IEC specification.





           The same oil can be used effectivly for outgassing tests with
           via in pad. In the last test I did with ten scrap boards dfrom
           different suppliers 2 outgassed on the pads from the vias.





           The procedure for through hole which could and has been applied
           to vias is on my web site which is in the download section.





           Hope this helps.








           Bob Willis
           Electronic Presentation Services
           2 Fourth Ave, Chelmsford, Essex, CM1 4HA England





           See us at APEX 2002  www.bobwillis.co.uk/workshops/apex/apex.htm





           www.bobwillis.co.uk
           Tel: (44) 01245 351502 Fax: (44) 01245 496123





           Single solution to your seminar, conference or roadshow
           www.seminar-registrations.com
           ---



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