Hi friends
I have a specific problem???. I had designed a 10
layer card which use rathyon make 29793 PROM and other
electronics. After fusing, mounting, soldering,
cleaning and conformal coating I found lid lift on the
top of the IC. It was severe on one IC and superficial
on other seven ICs.
I use 50 W soldering Iron for soldering (weller, 320
oC soldering temp, used type R rosin flux and
multi-core solder to solder)
card cleaned with ISO propyl alcohol and dried at 45
oC jet air.

Card latter coated with conathane CE1155 (brush
coated).

Before thorough cleaning and coating card was tested
for functional verification and found ok.

But after thorough cleaning and conformal coating card
did not function at all. A detailed visual inspection
revealed IC lid lift on one of the PROM, The same is
replaced and card is functioning well. As a matter of
fact I made around 30 boards and all are working well
except this one which has the lid lift. I have
contacted my stores manager he consistently says he
had checked the devices before delivery to soldering
area.

Now my question is what could have made this lid lift
of PROM 29793 from rathyon. I am in dark now. is there
anybody who had similar experience!!!!. please reply
why it happened and what should i do for avoiding this
problem in future.

Regards James M Paul
Senior Design Engineer.




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