Hi everybody,

It appears that one of our component suppliers is converting it's SnPb plating process to one that is lead free.  I'm not totally up to date on the "lead free" topic, and I'd like to ask those who are familiar if there is reason for concern from the following announcement excerpts from ON Semiconductor:

"This is a General Announcement that ON Semiconductor is converting the                              
External Lead Finish/Plating to a Pb (lead) Free Finish/Plating process.                            
ON Semiconductor recognizes the increasing demand for environmentally                              
friendly products. ON Semiconductor will convert the existing                                      
SnPb (Tin Lead) lead finish/plating to a Pb Free solution on a package by                          
package basis. This conversion will take place from June 2003 to March 2004,"

"All Products referenced by this PCN will use a Pure Matte Tin (Sn) lead finish. 100% Matte Sn is the predominate Pb Free finish in the industry.  One of the benefits of using 100% Matte Sn, is it allows for "backward compatibility" in the manufacturing process. . When a device is described as "backward compatible", it refers to the ability for a manufacturer to use their current SnPb Printed Circuit Board (PCB) solder and assembly process.

" Based on customer feedback and the uncertainties within the electronics
industry, ON Semiconductor is modifying its plans for the package by
packageconversion to Pb (Lead) Free plating that was announced under Process
Change Notification (PCN) #12797 and the General Announcement (GA) #12770, both
located at www.onsemi.com."

Is it true that the use of 100% Matte Sn would be "backwards compatible", and have no effect on soldering and reliability?  According to Jennie S. Hwang, Modern Solder Technology for Competitive Electronics Manufacturing, a high tin content would provide better wettability, but would also promote intermetallic compound formation and possibly lead to poor solderability.  According to my supplier, other component manufacturers are similarly removing SnPb from their lead plating. Any thoughts?  Thanks for the feedback.

Howard Watson
SMT Manufacturing Engineer
---------------------------------------------------
Technet Mail List provided as a free 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 847-509-9700 ext.5315
-----------------------------------------------------
AMETEK/Dixson