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Tin Lead ST failure

hello,
I'd to inquire regarding other contributor that causes Tin Lead ST failure other that chemical; concentration etc..Do trim and form process can contribute to Tin lead Solderability Failure?if yes what are the factors that affect this failure?We have encountered Solderability failure on 1 package only, and we are running with only one machine(Tin Lead), all the packages that runs to this machine was PASSED the Solderability test but on 1 package was declared failure which was processed on the same day...based on the investigation all chemical concentration was within the specs..the only variable that I suspected is the trim and form process,can this be one contributor that affect Solderability failure?and what factor which contributes this issue on trim and form?

Gilbert Tresvalles
semicon - Philippines
2006

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2006

Hi,
Solderability problems are mostly attributed to the precleaning problems only. In what base material you are facing the problem. Descale effect will be different in C7025 and other copper alloys. Check for virgin copper colour after the descale stage. Shall I know at what solderability conditions the particular package is failing?

Trim and form systems can create solderability problems sometimes due to excess shaving of the plated deposit and if oil used during the maintenance process is carried on to the leads of the devices.

C.Prince
Semiconductor plating engineer - Chennai, India

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Hi Gilbert,

I've read in some articles that Trim and Formed machine affect the solderability of units through SCC or better known as stress corrosion cracking. You could search in the internet for this topic if you want the full detail.

Good luck...to your research

regards,
Ella Delos Santos

Graciela Delos Santos
Power Devices for Semiconductor - Cebu City, Philippines
2007