We routinely re-ball ceramic BGAs without incidence.
Jim Marsico
Senior Engineer
Production Engineering
AIL/Electronics Systems Group
An EDO Company
[log in to unmask] <mailto:[log in to unmask]>
-----Original Message-----
From: Gabriela Bogdan [SMTP:[log in to unmask]]
Sent: Friday, March 02, 2001 1:12 PM
To: [log in to unmask]
Subject: Re: [TN] Reballing concern
Daan,
Are ceramic BGA's OK for reballing?
Gaby
"d. terstegge" wrote:
> Hi Brad,
>
> I share your concern, and for that reason we do reballing only on
prototypes, where the customer is interested in one thing only: getting a
working board, as soon as possible.
> Some time ago I did an experiment where I reballed and reworked a
BGA five times. It still worked ! (but the real question remains: how long
will it keep functioning ?).
>
> Kind regards,
>
> Daan Terstegge
> Unclassified mail
> Personal Website: http://www.smtinfo.net
>
> >>> Brad Kendall <[log in to unmask]> 03/02 3:05 pm >>>
> I see that Steve is having parts reballed. I never
> reballed BGA parts, but have heard of a lot of people
> doing it lately. I have concerns with reballing and
> would like to see if you guys agree. Now, it is
> critical that most BGA parts are NOT exposed to air
> prior to reflow. I have seen some that have been and
> they popcorn. So we always kept them sealed or in a
> nitrogen cabinet. So, now you have run a part,
> determined there is an open or short, but that the
> chip itself is good. The board may have been built a
> week ago, may be sent out of house for rework, thus
> exposed to climate changes. Then heat is put on it in
> rework. This part probably has moisture in it and may
> popcorn. Then you reball and put heat on it again!
> Is the part any good? It has seen a minimum of 3 heat
> cycles, if it saw heat for backside glue cure or
> double reflow or wave, then it has seen even more.
>
> I understand reballing is done to save expensive
> parts, but the risk of destroying the part during
> rework is a major concern.
>
> Brad Kendall
> --- Bob Perkins <[log in to unmask]> wrote:
> > Hi Steve
> >
> > One thing I have noticed is that if you do not have
> > your voiding under
> > control you can create bridging. I have seen a
> > voids large enough to
> > expanded the ball enough to invade in the space of
> > the next ball, and if
> > that ball has a large void also a bridge can occur.
> > If this is an known
> > issue then a new paste may be in order.
> >
> > I see two issues with your profile that could
> > possibly be causing a
> > problem, I don't think all the balls on the BGA are
> > reflowing at the same
> > time. I think you can improve this by setting up
> > your reflow closer to 183
> > before spike. There could also be a hot slump issue
> > also at the beginning or
> > reflow, I would recommend you try this to get a more
> > simultaneous reflow.
> >
> > 130 160 180 183 240
> > 130 160 180 183 240
> >
> >
> > How you guys doing in Seattle after that shake up?
> > We felt it up here in Vancouver.
> >
> > Bob Perkins
> > SMT Manufacturing Process /
> > Automation Technician
> > Aitmronics-Delta
> >
> >
> >
> >
> > -----Original Message-----
> > From: Stephen R. Gregory [mailto:[log in to unmask]]
> > Sent: Tuesday, February 27, 2001 1:34 PM
> > To: [log in to unmask]
> > Subject: [TN] Heat-sinked BGA Bridging...
> >
> >
> > Hi all!
> >
> > This topic is a "moldy-oldie", but I've started to
> > experience bridges again
> > with this TI DSP (TMS320C6201GJC200). I've been
> > doing okay up unil recently.
> > We build these boards in work orders of around 25
> > pieces.
> >
> > Our last run we had 7 boards bridged out of 25!!
> > Sent the boards out to be
> > reworked. I asked that they be x-rayed before and
> > after, and to my surprise
> > after looking at the x-ray images, they were all
> > bridging in the same
> > general
> > area.
> >
> > It's a 4-row periphery BGA, and the bridges are
> > occuring on the inner two
> > rows, around the center of the part, at the same
> > side of the part.
> >
> > What's funny, is that the vendor we use to rework
> > the boards for us is
> > having
> > difficulty as well. We've been asking him to remove,
> > re-ball, and re-install
> > the part, they said they've been having about a 50%
> > success rate doing
> > this...they've been getting the bridges too. They
> > have a nice full-blown SRT
> > BGA rework station and do this for a living.
> >
> > I print 6-mils of paste (square apertures for the
> > BGA), have a Conceptronic
> > HVN-70 which I run:
> >
> > 150 160 170 180 240
> > 150 160 170 180 240
> >
> > 25-in. per min
> >
> > We never have had these problems before...it all
> > started when TI put the
> > heatsink into the top of the part. I've looked at
> > our paste print and it's
> > dead on, placement is dead on too, we verify that
> > with a Ersascope.
> >
> > My question is could there be something wrong with
> > the part? Warping causes
> > bridges at the corners, right? Why would it bridge
> > in the interior rows at
> > the same general area?
> >
> > Thanks in advance!
> >
> > -Steve Gregory-
> >
> >
>
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> >
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"d. terstegge" wrote:
> Hi Brad,
>
> I share your concern, and for that reason we do reballing only on
prototypes, where the customer is interested in one thing only: getting a
working board, as soon as possible.
> Some time ago I did an experiment where I reballed and reworked a
BGA five times. It still worked ! (but the real question remains: how long
will it keep functioning ?).
>
> Kind regards,
>
> Daan Terstegge
> Unclassified mail
> Personal Website: http://www.smtinfo.net
>
> >>> Brad Kendall <[log in to unmask]> 03/02 3:05 pm >>>
> I see that Steve is having parts reballed. I never
> reballed BGA parts, but have heard of a lot of people
> doing it lately. I have concerns with reballing and
> would like to see if you guys agree. Now, it is
> critical that most BGA parts are NOT exposed to air
> prior to reflow. I have seen some that have been and
> they popcorn. So we always kept them sealed or in a
> nitrogen cabinet. So, now you have run a part,
> determined there is an open or short, but that the
> chip itself is good. The board may have been built a
> week ago, may be sent out of house for rework, thus
> exposed to climate changes. Then heat is put on it in
> rework. This part probably has moisture in it and may
> popcorn. Then you reball and put heat on it again!
> Is the part any good? It has seen a minimum of 3 heat
> cycles, if it saw heat for backside glue cure or
> double reflow or wave, then it has seen even more.
>
> I understand reballing is done to save expensive
> parts, but the risk of destroying the part during
> rework is a major concern.
>
> Brad Kendall
> --- Bob Perkins <[log in to unmask]> wrote:
> > Hi Steve
> >
> > One thing I have noticed is that if you do not have
> > your voiding under
> > control you can create bridging. I have seen a
> > voids large enough to
> > expanded the ball enough to invade in the space of
> > the next ball, and if
> > that ball has a large void also a bridge can occur.
> > If this is an known
> > issue then a new paste may be in order.
> >
> > I see two issues with your profile that could
> > possibly be causing a
> > problem, I don't think all the balls on the BGA are
> > reflowing at the same
> > time. I think you can improve this by setting up
> > your reflow closer to 183
> > before spike. There could also be a hot slump issue
> > also at the beginning or
> > reflow, I would recommend you try this to get a more
> > simultaneous reflow.
> >
> > 130 160 180 183 240
> > 130 160 180 183 240
> >
> >
> > How you guys doing in Seattle after that shake up?
> > We felt it up here in Vancouver.
> >
> > Bob Perkins
> > SMT Manufacturing Process /
> > Automation Technician
> > Aitmronics-Delta
> >
> >
> >
> >
> > -----Original Message-----
> > From: Stephen R. Gregory [mailto:[log in to unmask]]
> > Sent: Tuesday, February 27, 2001 1:34 PM
> > To: [log in to unmask]
> > Subject: [TN] Heat-sinked BGA Bridging...
> >
> >
> > Hi all!
> >
> > This topic is a "moldy-oldie", but I've started to
> > experience bridges again
> > with this TI DSP (TMS320C6201GJC200). I've been
> > doing okay up unil recently.
> > We build these boards in work orders of around 25
> > pieces.
> >
> > Our last run we had 7 boards bridged out of 25!!
> > Sent the boards out to be
> > reworked. I asked that they be x-rayed before and
> > after, and to my surprise
> > after looking at the x-ray images, they were all
> > bridging in the same
> > general
> > area.
> >
> > It's a 4-row periphery BGA, and the bridges are
> > occuring on the inner two
> > rows, around the center of the part, at the same
> > side of the part.
> >
> > What's funny, is that the vendor we use to rework
> > the boards for us is
> > having
> > difficulty as well. We've been asking him to remove,
> > re-ball, and re-install
> > the part, they said they've been having about a 50%
> > success rate doing
> > this...they've been getting the bridges too. They
> > have a nice full-blown SRT
> > BGA rework station and do this for a living.
> >
> > I print 6-mils of paste (square apertures for the
> > BGA), have a Conceptronic
> > HVN-70 which I run:
> >
> > 150 160 170 180 240
> > 150 160 170 180 240
> >
> > 25-in. per min
> >
> > We never have had these problems before...it all
> > started when TI put the
> > heatsink into the top of the part. I've looked at
> > our paste print and it's
> > dead on, placement is dead on too, we verify that
> > with a Ersascope.
> >
> > My question is could there be something wrong with
> > the part? Warping causes
> > bridges at the corners, right? Why would it bridge
> > in the interior rows at
> > the same general area?
> >
> > Thanks in advance!
> >
> > -Steve Gregory-
> >
> >
>
----------------------------------------------------------------------------
> > -----
> > Technet Mail List provided as a free service by IPC
> > using LISTSERV 1.8d
> > To unsubscribe, send a message to [log in to unmask]
> > with following text in
> > the BODY (NOT the subject field): SIGNOFF Technet
> > To temporarily halt delivery of Technet send the
> > following message: SET
> > Technet NOMAIL
> > Search previous postings at: www.ipc.org > On-Line
> > Resources & Databases >
> > E-mail Archives
> > Please visit IPC web site
> > (http://www.ipc.org/html/forum.htm) for additional
> > information, or contact Keach Sasamori at
> > [log in to unmask] or 847-509-9700
> > ext.5315
> >
>
----------------------------------------------------------------------------
> > -----
> >
> >
>
----------------------------------------------------------------------------
-----
> > Technet Mail List provided as a free service by IPC
> > using LISTSERV 1.8d
> > To unsubscribe, send a message to [log in to unmask]
> > with following text in
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> > To temporarily halt delivery of Technet send the
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> > Search previous postings at: www.ipc.org > On-Line
> > Resources & Databases > E-mail Archives
> > Please visit IPC web site
> > (http://www.ipc.org/html/forum.htm) for additional
> > information, or contact Keach Sasamori at
> > [log in to unmask] or 847-509-9700 ext.5315
> >
>
----------------------------------------------------------------------------
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>
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>
>
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> Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
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> information, or contact Keach Sasamori at [log in to unmask] or
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>
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>
>
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> Search previous postings at: www.ipc.org > On-Line Resources &
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> Please visit IPC web site (http://www.ipc.org/html/forum.htm) for
additional
> information, or contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
>
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847-509-9700 ext.5315
----------------------------------------------------------------------------
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