LEADFREE Archives

November 2006

Leadfree@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:
Vladimir Igoshev <[log in to unmask]>
Reply To:
(Leadfree Electronics Assembly Forum)
Date:
Wed, 15 Nov 2006 10:25:09 -0500
Content-Type:
text/plain
Parts/Attachments:
text/plain (112 lines)
Hi Ioan,

 

What is the original size of the balls?

 

Regards,

 

Vladimir

 

 

Vladimir Igoshev, Ph.D.

Physical FA Laboratory Manager

AMD Organization

Ph: 905-882-2600, x 6611

Fax: 905-882-5536

Cell: 416-300-4203

E-mail: [log in to unmask]

 

 

-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Tempea, Ioan
Sent: Wednesday, November 15, 2006 9:57 AM
To: [log in to unmask]
Subject: [LF] Separation in BGA joints

 

Hi TNLF-ers,

 

please have a look at http://stevezeva.homestead.com/files/Ioan_Ball.jpg
, many thanks to Steve again.

What can I tell you: no-clean SAC305 at the bottom, the balls read a
sort of SAC with 3%Ag and 1.75%Cu

The reflow profile seems to be OK, I measure 246C under the periphery of
the BGA, with a thermocouple that is squeezed there. I know it is not
rigorous, I did not drill, I am not measuring inside the joint. But even
if I am 20C off, the materials should be molten and coalesce, isn't it?

The intermetallics solder paste - PCB pad are OK, the wetting is good,
the BGA balls seem to have changed shape, they are almost collapsed,
there is physical contact between the balls and the paste, but no joint.

The question is: why do I see the separation line? What can cause that?
Should I bother investigating the process, or do I have a sort of
contamination? Or the BGA ball alloy has a higher melting point?

Thanks,

Ioan

 

 

 

 

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

ATOM RSS1 RSS2