TECHNET Archives

March 2008

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:
"David D. Hillman" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, [log in to unmask]
Date:
Mon, 3 Mar 2008 16:42:17 -0600
Content-Type:
text/plain
Parts/Attachments:
text/plain (90 lines)
Hi! I would agree with the solderability degradation that you were 
provided. A tin over copper surface finish is going to readily oxidize and 
also have copper/tin diffusion issues at a temperature of 175C, especially 
if the time duration is longer that 10-15 minutes. You may be able to 
restore the solderability of the components by using a very aggressive 
flux in a solder dipping process. Good Luck.

Dave Hillman
Rockwell Collins
[log in to unmask]




- bogert <[log in to unmask]> 
Sent by: TechNet <[log in to unmask]>
03/02/2008 07:47 AM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
- bogert <[log in to unmask]>


To
[log in to unmask]
cc

Subject
[TN] Matte Tin Plated Diode Solderability issue






March 2, 2008

Folks, we have an OEM that purchased axial leaded diodes from On 
Semiconductor.  Since the diodes were not mil-spec parts, the OEM sent 
them 
to a test house for qualification and electrical screening testing.  The 
screening is performed at 175C which I believe is the max storage temp of 
the part.  They also performed solderability testing which failed (<90% 
wetting).

The OEM subsequently solder dipped the parts in Sn63 solder and was able 
to 
solder them OK.

The part manufacturer indicated the solderability problem was most likely 
caused by tin migration due to the testing at 175C.

Seems to me that since MIL-PRF-19500 includes electrical screening 
testing, 
the parts should have been able to withstand the full screening testing 
with 
no solderability failures since the parts most likely were made on the 
same 
line and samp processing as mil spec parts.

Any info you can provide on tin migration or on the manuf position that 
the 
solderability failure was the result of the testing at 175C would be 
appreciated.  Have other folks experienced solderability issues for matte 
tin plated parts?

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