Werner,
I am not wrong. People run Sn/Pb profiles way too hot so that they don't
have to do any process development. If all of your solder joints reach a max
of 205degC you will form a very good and reliable solder joint. I have
proven this in my own process experience without any reliability issues.
I am, however, not so naïve that I think there are no thermal gradients but
in my experience the BGA solder joints tend to be the coolest on the board
and if those are peaking at 217degC the majority of the solder joints on the
balance of the board are getting too hot.
Joel Mearig
Delta Tau Data Systems, Inc.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier
Sent: Wednesday, November 23, 2005 9:59 AM
To: [log in to unmask]
Subject: Re: [TN] Lead Free BGAs
Hi Joel,
Unfortunately, you are wrong. The Sn/Pb profile peak should minimum at
203degC for 5 seconds at the slowest heating SJ, which makes most of the
rest of the
assembly hotter.
Regards,
Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL 32174 USA
Phone: 386-437-8747, Fax: 386-437-8737, Cell: 386-316-5904
E-mail: [log in to unmask], Website: www.engelmaier.com
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