Dirk,
     
     Funny you should ask.  There has been quite a bit of discussion on 
     Technet before about this and very little commonality between 
     companies.  At Hitachi, we have concentrated on humidity control for 
     the most critical components (DRAM's, SRAM's, Controllers, Processors, 
     ASIC's, etc...).  We generally try to insert them within 48 hours of 
     opening the receiving package so we don't have to worry about moisture 
     control.  If we need to store the parts longer than that, we have a 
     controlled list of the parts which must be baked prior to assembly.  
     We bake those parts (125C for 24 hours, including bare boards 
     sometimes) to eliminate any absorbed moisture.
     
     Sometimes, we get special requirements from our contract customers to 
     store parts in a dry environment.  For this purpose we keep dry boxes 
     for a limited amount of storage place (not in the Vidmar equipment).  
     We use dry nitrogen to keep them humidity free, but I see no reason 
     why you couldn't use dry air with the same specs (might be cheaper).
     
     Regards,
     
     Roger Held
     Hitachi Computer Products (America), Inc.


______________________________ Reply Separator _________________________________
Subject: Moisture Sensitivity
Author:  [log in to unmask] at Internet-HICAM-OK
Date:    6/27/96 1:14 PM


Hey folks,
Ok, we all know that certain surface mount components are moisture 
sensitive.  This means that they may suffer damage during reflow 
soldering conditions due to moisture expansion.
We are currently attempting to develop a company policy regarding these 
little beasties, but are having some difficulty.  
The problem is compounded by the fact that no one packaging standard 
is followed universally.  We have component bags come in with 
everything from simple moisture warning labels to labels with specific
instructions about humidity and temperature exposure -- anything but the 
IPC's recommended 1-6 classification. 
So my question is this: how are other companies handling these 
components?  
Also if you're using Vidmar type cabinets, please specify what gas 
you're using to keep them dry (I'm trying to determine if dry compressed 
air is adequate).
Thanks!
Dirk Bellamy
Manufacturing Engineer
Current Electronics