Re: gEDA-user: Baking chips to dehumidify before reflow

[Steve Meier <smeier@xxxxxxxxxxxxxxxxxxx>]

From: http://www.necel.com/pkg/en/mount/3/3_3/3_3_5/index.html



[Baking time]

The recommended
baking time is
indicated by using
the symbols, each
consisting of two
numerical digits,
shown in the table
on the right.

 Symbol 
 Baking
  Time
  (When
Stored at
 125ÂC) 
   00 
 Baking
unnecessary
   (0
 hours) 
   10 
10 hours
 MIN., 
72 hours
  MAX. 
   20 
20 hours
 MIN., 
72 hours
  MAX. 
   36 
36 hours
 MIN., 
72 hours
  MAX. 



On Thu, 2006-06-08 at 08:58 -0400, Randall Nortman wrote:
> I've got some LQFP chips that I've been storing, with the bag opened,
> for a bit longer than I really should have.  The indicators on the
> humidity cards have started to turn pink, so I'm worried that they
> will have absorbed too much humidity and if I try to reflow them now,
> they'll "popcorn" (i.e., trapped moisture turns to steam and
> evaporates, cracking the package and/or die).  Anybody have any
> suggestions on the best way to do this using common household
> equipment?  I guess I just stick them in an oven at lowish temperature
> for a while, but what temperature and for how long?  I checked the
> datasheets for the chips (Atmel AT91SAM7X256 and Micrel KS8721CL) and
> didn't see any useful information.