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Thermal fatigue of solder joints



Thermal fatigue of solder joints | 26 October, 2000

What would be a typical thermal test regime to verify the quality of solder joints for high specification applications - what would be the specific benefits of utilizing a "HALT" process over other traditional test techniques ?

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Re: Thermal fatigue of solder joints | 26 October, 2000

I am not familiar with the "HALT" terminology. Do you mean HAST testing? As for thermal fatigue, the most severe conditions are typically those cited for military and/or satellite applications. There are several temperature ranges that are used today; they are based upon the MIL-STD-883C document: -55-85�C; -55-125�C (most popular); and -65-150�C. The latter is sometimes used by the automobile manufacturers to represent under-the-hood enviroments. The high-end, non-military electronics will use 0-100�C as the temperature cycling limits (e.g., telecommunications). But remember, if the product uses an organic laminate, one does not want the high end temperature to exceed the glass transition temperture of that laminate; then, the test data on the solder joints become larglely meaningless due to softening of the laminate structure.

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Re: Thermal fatigue of solder joints | 25 November, 2000

HALT is an approach to stimulate a failure till its existence. It is mainly used during product design and development phase. Traditional tests are mainly used to prove "no" failure but HALT is to make failure for information to improve in design of a product. Besides temp extremes chosen, the number of cycles is also important. Automotive customers usually require at least 500cyc @-65C/+150C.

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