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48:11 1996 |
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Address,
An industry move 8 years ago was to move away from from V-HAL to HASL
due to coplanarity issues on fine pitch devices. To me, back then, it
made all the sense in the world. After further testing we found that
HASL did not provide the needed coplanarity necessary and solder
puddles were more apparent on the component side (top) lands versus
the solder side (bottom) lands, however the panel was run.
Because of that, V-HAL were re-thought, boards were turned at an angle
for better coplanarity in addition to several other variables.
Because of the technology changes there has been a move towards V-HAL,
since the solder height is better controlled, for lack of a term.
My discussion today throws all this out the door. HASL it seems,
now controls solder height and provides better coplanarity than V-HAL.
#1 Aside from vendor process control, I would like to hear from
others on WHAT is WHAT anymore? Lets forego alternative surface
finishes in your responses.
#2 Re-HAL boards should not be concern anymore if properly done?
I am seeing some SnPb oxidation and would prefer to re-HAL boards.
Aside from the standard concerns, thermal excursions (cycling)
(laminates are way ahead now, considering solder hasn't changed),
inducing bow and twist, etc, what are some unique concerns.
John Gulley = QA
INET Inc.
972-578-3928
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