This is a very common practice. There are companies out there who
manufacture adapters that are used to adapt a new BGA with a different
land pattern (or a leaded component such as a gullwing, or even a BGA
socket) to an existing land pattern on the PWB. (Check out Ironwood,
Inc. or Gryphix)
You can do this yourself by purchasing the sphere pattern you need from
www.winslowautomation.com and attaching the pattern to the
daughterboard. On top of the daughterboard, you can assemble pretty much
anything to want.
I assume you want to adapt a circuit or component to an existing board.
Another method of doing this is to use two stencils. The first stencil
is used to deposit solder paste (or tacky flux) and then removed. The
second stencil sits on shouldered pins just above the paste. Its
apertures are slightly larger than the ball diameter desired. Loose
balls are then poured over this stencil in such a way that a single ball
fills each available hole, and then the extra balls are poured off into
a holding tray. The 2nd stencil remains in place through the reflow.
Weller makes this type of ball attachment kit. You can buy spheres from
a number of solder sources, but I like www.easyspheres.com
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Taylor, Royce
Sent: Tuesday, September 20, 2005 6:33 AM
To: [log in to unmask]
Subject: Re: [TN] BGA Adpater board
Did this for a customer years ago at Hadco (Remember it Carrie??)
it was a 352 ball BGA land pattern (on the bottom) with a smaller BGA
and chip resistors/capacitors mounted on the top side. If I remember
correctly we attached the solder spheres 1st by printing paste with one
stencil and then using another stencil, placed the solder spheres
(apertures were big enough for the solder spheres to fall through).
After reflow & wash we built the top side of the board (in carrier
fixtures). When we mounted to the main PCB we were able to pick it out
of a matrix tray and place it during our normal process.
I can take pictures and post them if you want an idea of what it looks
like
Royce
************************************************************************
*
Royce Taylor
Process Engineering/Production
Suntron Corporation NEO
104 Glenn Street
Lawrence, MA 01843
(978)747-2061 voice
(978)747-2010 fax
[log in to unmask]
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Smith, Richard
Sent: Tuesday, September 20, 2005 7:11 AM
To: [log in to unmask]
Subject: [TN] BGA Adpater board
Folks,
We have a requirement to design a daughterboard that will be soldered to
the motherboard in place of BGA devices. This means that BGA balls are
required (on the secondary side) of the daughterboard so it can be
soldered to the existing BGA pattern(s) on the motherboard, as if it
were just another BGA. I've not heard of this being done before so I'm
hoping others may be able to provide some insight in regards to
feasability and process.
Thanks Much!
Rick
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 1.8e 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 1.8e
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
-----------------------------------------------------
|
