Hi Francois.
i am using Vacuum Reel Bake Out here at Sanmina-SCI in Colorado at 6000 feet.
We use Relative Humidity measurements for ESD and MSD  work but i wonder if Absolute Humidity wouldn't be a better parameter for the chemical diffusion of vapor into MSD's. (Since it is more like a chemical reaction than a surface effect on materials).
For my RH readings (Calculated off of a psychometric chart) i have to add +6% for my altitude correction, but the Absolute Humidity is  independent of pressure. 
There was a good article on this in the Journal of Environmental Sciences Dec 1965 by Frank Quinn.
If you have any other unoublished articles i would to get a copy of them.
i think i have all of your published articles.


Paul Signorelli
Reliability Engineer
Sanmina-SCI Corporation, Plant 432
702 Bandley Dr.
Fountain, CO 80817

eMail address: [log in to unmask]
Phone: 719-382-2352,   Fax: 719-382-2520

>>> [log in to unmask] 06/21/02 07:50AM >>>
Hi Marki,

I don't think that anyone has answered your question yet, so here it is :

The proper bake conditions, along with other handling guidelines for
moisture-sensitive devices are all documented in J-STD-033, a joint
IPC/JEDEC standard. The standard does not address vaccum bake but it
includes a table for simple temprature bake cycles at 40C for components in
reels and 125C for components in trays. The actual duration varies based on
the MS level of the component and its body thickness.

The default bake cycle for components in reels is 68 days at 40C. (yes 68
days as in two months). Most assemblers cannot live with this kind of cycle
time so the solution is to remove all components from the reel, bake them at
125C and then re-tape them or use them in JEDEC trays. The default cycle
time at 125C is 48 hours. I am aware that some people use a combination of
vaccum and temperature to reduce the bake duration and I can provide you
with some technical articles and oven suppliers if you are interested.

Regards,

Francois Monette
Cogiscan Inc.
Tel : 450-534-2644
Fax : 450-534-0092
[log in to unmask] 
www.cogiscan.com 


Date:    Tue, 18 Jun 2002 09:37:43 +0200
From:    Marki Sasportas <[log in to unmask]>
Subject: Moisture sensitive device

 Hi Technos,

Can someone tell me at what conditions  (Vacuum&Temperture) should I dry
those components which are
packed in reel.

 Thanks in advance,
Marki Sasportas.

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