Hi Dason,
Yes I was talking about the same paper. This is the best technical information available to clearly explain the physics of moisture diffusion inside a plastic package. Many of the guidelines contained in the current J-STD-033 are derived from this research data.
As far as dry storage is concerned, I would be very careful about using any claims that rely on weight reduction. This is a simplistic approach that was used many years ago, before the above paper was published and before the release of J-STD-033. The basic flaw with the method is that it assumes that the weight content is uniform throughout the package. What the Lucent paper explains is that the moisture content is actually a slowly moving gradient and that the location of the moisture is more important that the overall moisture content. i.e. A large amount of moisture will be harmless if it is on the surface of the package (after a short exposure time) whereas a very small amount of moisture at the critical interface can lead to cracks and delaminations (as you would find when previously exposed components have been stored in a dry box for a long time).
That is why the standard only allows you to reset the floor life clock in very specific conditions of prior exposure followed by sufficient time in dry storage, as defined in the short duration exposure rule (Ref. J-STD-033, 7.1.2). Using any other rule to account for dry storage is not based on good science and it is not backed up by an industry standard supported by component vendors.
For this reason you might have a hard time to convince any serious customer about using rules that are different from the IPC/JEDEC standard.
Let me know if you have any questions on the above.
Regards,
Francois Monette Cogiscan Inc.
reply »
Recently, our customer request us to use the N2 dry cabinet ...
- May 14, 2002
by
Dason C
Hi Dason,
Here is some relevant information that you mig...
- May 14, 2002
by
fmonette
