Hey Bud: Thanks for the response the other day. We currently use "Jeff�s Method #2: The Drummel Tool."
Short answer to your brother is ... yes, probably.
Expanding a bit: � It would be surprising not to use a flux to help reflow the solder balls to pads on the wafer followed by cleaning. � You�re correct, heating will increase the oxidation on the surface of the solder balls, whether this limits the ability to form a solder connection ... yagot me. That depends on how much oxidation, activity of the flux, etc. � Routine heating will not change the basic alloy of the solder ball. Consider the tin / lead phase diagram (http://www.umist.ac.uk/~intmic/phase/pbsndiag.htm). As you heat (cool) the alloy, you move straight up (down) through the phases. The constituents of the alloy don�t change. Material would have to be added or subtracted to change the alloy. � Continuing with this line of thought, heating undoubtedly will increase the intermetallic layer thickness between the solder ball and the pad on the wafer, whether this: - Affects LT reliability ... yagot me. That depends on temperature, time, product application environment, etc. - Grows the IM layer so thick that it won�t solder is possible, but then the ball would have to be entirely converted to whatever IM forms between the solder and the pad materials that are used at TI. � One final point, engineers can be very tricky people, sometimes using words with shades of meaning that regular carbon based units don�t interpret well. So, I wouldn�t go to mattress on this until I well understood the engineer�s point of view.
Expanding on this to better understand your brother�s engineer�s thinking: If the engineer is thinking that there is flux mixed with the solder of the ball and that it will be burnt-off during the heating process, he is correct that the ball will be unsolderable without additional flux.
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