In a message dated 09/28/00 22:11:12, [log in to unmask] writes:
>My question is: are there any known problems on solder joint and PCB
reliability
>issues if the assembly is additionally cured for one hour at 175 degrees
>C for the die attachment process?

Hi Kuan,
Your curing process is what I have termed 'extraordinary' in the e-mail
subject: "Re: [TN] Solder Joints". At this temperature and duration, you will
see a significant increase in the thickness of the intermetalic layers with a
significant change in the alloy composition of the remainder of the solder
joint volume, because the IMC formation consumes the available Sn. Also, you
will see a tremendous growth in the grain structure of the SJ. None of this
is particulalry good for the SJs, even though, I can not think of anything
published on this.
Whith the cure temperature this high, why on earth do you need to the
soldering first?

Werner Engelmaier
Engelmaier Associates, L.C.
Electronic Packaging, Interconnection and Reliability Consulting
7 Jasmine Run
Ormond Beach, FL  32174  USA
Phone: 904-437-8747, Fax: 904-437-8737
E-mail: [log in to unmask], Website: www.engelmaier.com

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