Hi Johannes,
Soldermask-defined (SMD) pads will result in stress concentrations due to the
resulting geometry of the solder joints. These stress concentrations reduce
reliability (read fatigue life)—for severly cycled (accelerated testing)
solder joints, the cylic life can be reduced by as much as a factor of 3, for
benign loading conditions as experineced in most applications the difference
is about 30%. In your case, the additional solder will result in somewhat
higher solder joints thereby increasing cyclic life.

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]


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