Removing surface-mounted ICs

From: Mark <mark_k_at_iname.com>
Date: Fri Jun 9 13:14:50 2000

Hi,

Thanks for the several helpful replies on this topic.


On Wed, 7 Jun 2000 Clint Wolff wrote:
> I would recommend against putting the board in an oven. This will
> result in the entire IC getting too hot, and possibly breaking.
> Modern plastic package absorb a small amount of water from the air.
> Heating the part may result in a small steam explosion. ICs are
> shipped from the factory in sealed bags with some desiccant inside.
> The label on the outside says to solder them down within a fairly
> short time after opening (couple days IIRC).

Ah, I have read about that.

IC manufacturers often specify a procedure to use when chips which may have
absorbed water are to be used. This involves baking at low temperature for a
while.

Assuming that (for the purposes of removing absorbed water) one plastic IC
package is the same as the next, at which temperature and for how long should
this baking be done?

The lowest setting on my oven is 70 degrees C. If that is low enough -- I
guess it should be as most ICs are specified for operation to 75 C or so -- I
may try putting the board in there for 12 or 24 hours, before turning the
temperature up to melt the solder.


-- Mark
Received on Fri Jun 09 2000 - 13:14:50 BST