Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


solder joint crack in post thermal cycling test at Dye & Pry

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#61586

solder joint crack in post thermal cycling test at Dye & Pry | 11 April, 2010

When we have sent some of motherboards for reliability testing in a tird party laoratory. It is found that when Dye&Pry is done after 600 cycles of Thermal Cycling, in LGA socket only one of the corner solder joing had 100% type 3 crack. All other solder ball joints are in tact. Also in the same board no other BGA (ICH & MCH) no cracks observed. What could have gone wrong. We had no problems with the lead free materials, ImAg finish PCB, reflow & wave profiles used, also the boards have passed functional test pre nd post reliability tests..Out manufacturing is totally lead free and all fixtures are complaince with respoect to strain guage tests.

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#61593

solder joint crack in post thermal cycling test at Dye & Pry | 13 April, 2010

Hi manchella, After ATC test, two different failure modes can be present: solder FATIGUE (into bulk) or BRITTLE INTERMETALLIC fracture. So, first you have to verify this. Moreover, which brand of SMT paste have you used ? The crack into solder joint will be after thermal stress, if is not adopted a correct solder alloy. I suggest you also to verify the quality of IS finishing (microvoid absence)... Hi

esca analysispcb.com

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