5/16/97                           GEN: H2O Bake out
 12:40 PM

Hello everybody:

We are trying to determine if a moisture removal bake is necessary for hand (soldering iron) and/or automated (screen print/vapor phase) multilayer PWB assembly.  
If baking is required, then what conditions should be used (time, temp, vacuum, etc.)?
What influence does extended storage under ambient conditions (60%R.H. 70oF) have?  Does anyone use a drybox for storage?
Once boards entered the assembly area (and baked - if necessary), how long before a re-bake is required?
We primarily use Type GIN glass/polyimide materials for passive chip SMT.  Boards that get assembled within a few days after fabrication would probably NOT require a bake, but we have to allow for extended storage - up to 5 years from date of manufacture.

Thank you in advance for any help

Gino Cochella
(310) 814-3955
TRW Inc.

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