Actually the only application I have needed personally for laser rework (as
opposed to laser soldering) is actually where the design engineers mirror
imaged two very large BGA's back to back on the same board (26 layer) and
then proceeded to surround the whole thing with several square inches of
memory "as close as possible" ro reduce the signal flight time, actually
there was effectively no other way of getting the parts off the board
without removing all and starting over.
John Burke
(408) 515 4992
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Bob Landman
Sent: Wednesday, February 03, 2010 8:42 PM
To: [log in to unmask]
Subject: Re: [LF] [TN] Laser soldering of BGA
Bob,
Seems to me that top down heating through the BGA would be best as you then
don't heat the board, as you said.
Also because you might have parts (like decoupling caps or termination
resistors) under the board.
But I'm just guessing as I've never done reballing. John and Richard will
have to respond to your questions.
Bob Landman
H&L Instruments, LLC
-----Original Message-----
From: Robert Kondner [mailto:[log in to unmask]]
Sent: Wednesday, February 03, 2010 9:23 PM
To: 'Bob Landman'
Subject: RE: [TN] Laser soldering of BGA
Hi,
Ok, dump question here:
For rework would a top and bottom IR source (non-laser) do the same thing?
Forming individual BGA balls make sense to me but not PCB heating.
The planes in a PCB will result in a lot of heat diffusion around the part.
I fail to see what bring a laser IR source brings to the equation?
Bob Kondner
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bob Landman
Sent: Wednesday, February 03, 2010 5:43 PM
To: [log in to unmask]
Subject: Re: [TN] Laser soldering of BGA
Dave,
Seems like a beautiful idea (the way Richard just described it), if I
understand what he's saying. By tilting the machine does the same thing
that they do in radiation therapy for cancer; limit the exposure to the
intervening substrate by constantly moving the part, focusing all the IR
energy on the solder ball.
MIL customers need SnPb solder balls on their parts and the manufacturers
have refused to provide them with balless packages. I assume this laser
process removes the balls and eliminates damaging thermal cycles?
Quite a few PERM members would be interested in this technique if it's as it
seems from the article Richard posted, a vastly superior way to reball
parts.
Bob Landman
H&L Instruments, LLC
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
Sent: Wednesday, February 03, 2010 5:31 PM
To: [log in to unmask]
Subject: Re: [TN] Laser soldering of BGA
Hi John - given that a wide variety of materials make up a component
construction, isn't there a fairly high risk of damaging a component if you
transmit the laser heat thru the package?
Dave Hillman
Rockwell Collins
[log in to unmask]
John Burke <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
02/03/2010 04:21 PM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to John Burke
<[log in to unmask]>
To
[log in to unmask]
cc
Subject
Re: [TN] Laser soldering of BGA
Yes actually I have used it many times.
The transmission is through the package from the top of the device (don?t
try it with a heat spreader or metal lid!) and the laser is set up to scan
up and down the ball pattern on the board continuously.
Since the transmission of the selected frequency (usually prime frquency
YAG) is at 1.06somthing micron wavelength, the thermal uptake of the package
is from mempory about 20% the rest being concentrated in the joints.
There are a number of machines available for doing this but very expensive
and usually for re-work not for placement.
Of course you could reflow that part from the other side of the substrate
using the same technique, but I have a question which is:
Why not use a "normal" reflow syatem"??
John Burke
(408) 515 4992
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Thayer, Wayne - IIW
Sent: Wednesday, February 03, 2010 2:07 PM
To: [log in to unmask]
Subject: Re: [TN] Laser soldering of BGA
OK, I've played with using a laser for soldering, but could you share how
the laser light manages to get to the ball beneath a BGA?
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Kelly
Sent: Wednesday, February 03, 2010 4:53 PM
To: [log in to unmask]
Subject: Re: [TN] Laser soldering of BGA
Hi Ioan,
What I know about laser soldering would not fit on the back of a postage
stamp but as far as the BGA and flex if the stiffener is FR-4 I suspect you
will have to underfill unless it is in a very benign environment - otherwise
use a metal stiffener.
Regards Steve Kelly
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Ioan Tempea
Sent: February-03-10 2:35 PM
To: [log in to unmask]
Subject: [TN] Laser soldering of BGA
Dear Technos,
Any insights on BGA laser soldering? It is for soldering a 15x15 mm BGA onto
a flex PCB. The flex is backed by a rigid substrate in the BGA zone, but due
to mechanical constraints this substrate cannot be thicker than 0.012".
Oh yes, lead-free.
Thanks,
Ioan Tempea, ing.
Ingénieur Principal de Fabrication / Senior Manufacturing Engineer T |
450.967.7100 ext.244 E | [log in to unmask] <mailto:[log in to unmask]> W |
www.digico.cc <http://www.digico.cc/>
N'imprimer que si nécessaire - Print only if you must
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 or
(re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per
day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 or
(re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet
NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send
e-mail to [log in to unmask]: SET Technet Digest Search the archives of
previous posts at: http://listserv.ipc.org/archives Please visit IPC web
site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100
ext.2815
-----------------------------------------------------
This e-mail and any files transmitted with it may be proprietary and are
intended solely for the use of the individual or entity to whom they are
addressed. If you have received this e-mail in error please notify the
sender.
Please note that any views or opinions presented in this e-mail are solely
those of the author and do not necessarily represent those of ITT
Corporation. The recipient should check this e-mail and any attachments for
the presence of viruses. ITT accepts no liability for any damage caused by
any virus transmitted by this e-mail.
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 or
(re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet
NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send
e-mail to [log in to unmask]: SET Technet Digest Search the archives of
previous posts at: http://listserv.ipc.org/archives Please visit IPC web
site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100
ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 or
(re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per
day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 or
(re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per
day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0 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 or
(re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per
day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-615-7100 ext.2815
-----------------------------------------------------
----------------------------------------------------------------------------
---Leadfee Mail List provided as a 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 Leadfree To temporarily stop/(start)
delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL/(MAIL)
Search previous postings at: http://listserv.ipc.org/archives Please visit
IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100
ext.2815
----------------------------------------------------------------------------
---
-------------------------------------------------------------------------------Leadfee Mail List provided as a 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 Leadfree
To temporarily stop/(start) delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL/(MAIL)
Search previous postings at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-------------------------------------------------------------------------------
|
