TECHNET Archives

November 2009

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Steve Gregory <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Steve Gregory <[log in to unmask]>
Date:
Mon, 23 Nov 2009 14:30:54 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (144 lines)
Hi Inge,

Sorry it took me a while to get this posted, I've been doing assembly quotes
a good part of the morning.

Yeah, Guy has quite the story to tell about his adventure, wish I could talk
about it, but then he would have to kill me...

But anyways here's your pics:

http://stevezeva.homestead.com/Image1.jpg

http://stevezeva.homestead.com/Image2.jpg

http://stevezeva.homestead.com/Image3.jpg

http://stevezeva.homestead.com/Image4.jpg

http://stevezeva.homestead.com/Image5.jpg

Steve





-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Hernefjord Ingemar
Sent: Monday, November 23, 2009 6:52 AM
To: [log in to unmask]
Subject: Re: [TN] solder fracture solderable?

I don't believe in the knife idea. Have my own way. Complicated, but works
(not always).
1. Cut out the area of interest (e.g. BGA) with good marginal. Use fine
blade diamond saw. Let it take time. Use cutting oil.
2. Clean from oil. Glue mount two thick metal plates to both sides of the
sample under test. Each plate has a hook attached to the plate.
3. Place the sample in at pull tester and pull apart until the BGA separates
from the board. Use low speed.

I've sent example on this to Steve Gregory. 

/Inge





 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Guy Ramsey
Sent: fredag 20 november 2009 21:28
To: [log in to unmask]
Subject: [TN] solder fracture solderable?

I was visiting a customer earlier this week. They were attempting to cut a
the top part off of a package  on package, BGA on top of BGA. 

They didn't want to reflow it off because they didn't want to damage the
balls on the bottom of the bottom package. 

They had made a little fixture affair with two knives adjusted to slice
between the two packages.  

They placed the PoP in the tool and pushed it through the knives, rotated 90
degrees and repeated the cycle. 

Most of the pads on top of the bottom package ended up with half a ball
remaining on the pad.

But some of the pads did not have any solder on them at all. The entire pad
was mat finish silver in color. 

None of these features would  accept solder. The number of pads without
solder varied from one or two to 30% of the pads.

 

I wondered if rather than cutting through, some of the connections has
simply fractured along the intermetallic, leaving a non-solderable surface
with this uniform appearance. 

Some of those observing conjectured that the package was bad, They
conjectured that the silver was merely solder loaded with gold and that the
nickel had never accepted solder. 

 

I asked where their SEM was and if they had EDAX equipment . . .  nope.

 

Would anyone care to guess  along?  How likely is it that prying off a BGA
would fracture the connection right along the intermetallic and leave a
completely non-solderable surface? 

 

 

 

 


---------------------------------------------------
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
-----------------------------------------------------

ATOM RSS1 RSS2