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:
Robert Kondner <[log in to unmask]>
Reply To:
Date:
Wed, 4 Nov 2009 11:54:18 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (120 lines)
Rex,

  Wow, what a you know what contest. :-(

 They complain about a 5C difference at 250C? Hitting 245 is good IMHO, the
absolute max looks like 260. You were above the 217 minimum.

Do you have any pin test functions like JTAG or ICT to verify joint
conductivity? Testing for manufacturing defects (MDA) using execution of
application logic is difficult at best. If they really think there are
manufacturing defects (opens, short) I would go for something to verify
connectivity parts. If there are many manufacturing defects then you have a
process problem. If there are none then it is an application problem.

Bob Kondner

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Rex Waygood
Sent: Wednesday, November 04, 2009 11:36 AM
To: [log in to unmask]
Subject: [TN] BGA Balls

We have built a batch of pcbs for a customer who supplied the pcbs. They
are 2mm thick 6 layer with 0.2mm vias and ENIG finish. None work fully,
they work intermittently at best. 

The customer was suspicious that we had not reflowed the BGAs correctly.

Our under BGA temp on a similar pcb is 245C (We now have some samples to
profile correctly)

The customer is suspicious due to the comment on page 753
http://www.atmel.com/dyn/resources/prod_documents/doc6221.pdf
<http://www.atmel.com/dyn/resources/prod_documents/doc6221.pdf>  where
it states a min of 250C

Close x-ray evaluation of the BGAs showed tear dropping along tracks,
uniform balls, everything looked tickety boo.

We offered to remove a BGA to see what was happening underneath.

2 corners showed a similar issue with the ball where it separated from
the BGA rather than the pcb.

The removal technique was to use a PDR IR rework station, under board
heating to bring topside pcb temp to 170C and then a lead free reflow
profile to bring the device up to reflow, manual removal.

I didn't have dye for dye and pry so thought this might show if there
was an ENIG problem.

I was surprised by the almost complete removal of ball at the device and
lack of evidence of solder.

Was this just caused by my investigation processes?

Was the ball device interface broken which prevented it from melting the
ball?

Any other clues?

Thanks

Rex

 

Hopefully Steve has received the images (sorry about the size!)

 
Rex Waygood
Technical Manager

Hansatech EMS provides value manufacturing through engineering and
quality

________________________________


Hansatech EMS Limited
Benson Road
Nuffield Industrial Estate
Poole
Dorset BH17 0RY
United Kingdom


Tel:
Fax:
DDI: 	+44 (0)1202 338200
+44 (0)1202 338202
+44 (0)1202 338222 	
[log in to unmask]
www.HansatechEMS.com <http://www.hansatechems.com/>  
 

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