Hi John -

You may want to check with your part suppliers, there are usually some 
recommendations on the specification sheets or generic part family spec 
sheets and they may state some restrictions that limit supplier liability 
for defective parts after soldering.  Check the websites.

120~125C is a good Temp range to remove moisture,

16 hours may be a bit long if the parts are baked in an oxygen (air) 
environment. The risk is oxidation of the Balls.  If you bake in oxygen, 
make sure the oven is clean and not used for baking any volatile materials 
such as inks, adhesives, etc  that outgass and leave residue on oven 
walls, this can contaminate parts.

If you are baking in a dry nitrogen environment (N2) 16 hours should be 
OK. 

IPC/JEDEC J-STD-20C is the industry standard for moisture sensitivity of 
plastic packages, you may refer to that for background information. This 
defines the categories of moisture sensitivity used for BGA packages and 
includes some useful guidelines to plot absorption/desorption curves, etc. 
Using these methods you can optimize drying time to minimize it without 
risk.

If you haven't got J-STD-20C I suggest your company purchase it, it's a 
foundation document for Plastic Packages.

Regards,

C.B. Katzko, CTO
Meadville Group
e-mail  [log in to unmask]
tel            +86 21 3774 7528
fax           +86 21 3774 7590
mobile   +86 13817362590

+++  Please note new tel & fax numbers.  +++



"John Ling (Jiazhao Ling)" <[log in to unmask]> 
发件人:  TGAsia <[log in to unmask]>
2008-01-29 10:42
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Hello, All:
   How to set up baking temperature and time to drive humidity off from 
BGA? Is 125 degree and 16 hours is a reasonable set-up.
   Thanks!
   John Ling
   Loud China