I concur with Werner..

An additional factor maybe the IC's lead plating...
Bad plating and insufficient temperature can combine to cause what you are
seeing..


Paul Edwards
Process Engineering
[log in to unmask]
Tel: 408-433-4700
FAX: 408-433-9988
Surface Art Engineering
81Bonaventura Dr.
San Jose, CA 95134
DUNS: 944740570
CAGE/NCAGE: 1XZ48

-----Original Message-----
From: Werner Engelmaier [mailto:[log in to unmask]]
Sent: Thursday, March 24, 2005 8:17 AM
To: [log in to unmask]
Subject: Re: [TN] QFP w/heatspreader co-planarity

Hi 'rnowland,'
I do not think your problem is co-planarity, but insufficient heat; that
copper heat sink works--well, like a HEAT SINK. Your QFP leads simply do not
get
hot enough-you are likely at the hairy edge, that is why some solder others
not.

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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