The joint IPC/JEDEC standards J-STD-020B and 033A are for non-hermetic
components only; it would not be appropriate to apply the baking
guidelines of J-STD-033A to PCBs.
IPC-HDBK-001 w/amendment 1 (Handbook and Guide to Supplement J-STD-001)
and IPC-PE-740A Troubleshooting for Printed Board Manufacture and
Assembly provide the most support regarding bare PCB baking. The
IPC-PE-740A committee has started revision effort and is interested in
comments/recommendations that can be included. The committee is
co-chaired by Patricia Goldman, PPG Industries Inc. for the Printed
Board Mfg portion and Greg Hurst, BAE SYSTEMS for the assembly
troubleshooting portion. Any comments/recommendations should be sent
directly to me (off net, please or I might miss them).
Jack Crawford
IPC Director of Professional Development and Assembly Technology
[log in to unmask]
847-790-5393
-----Original Message-----
From: Glenn Pelkey [mailto:[log in to unmask]]
Sent: Tuesday, February 11, 2003 7:35 PM
To: [log in to unmask]
Subject: Re: [TN] Moisture in Raw Boards
I guess I would apply the Jedec standards for this, J-STD-020 and
J-STD-033, taking into account thickness and appropriate sensitivity
level.
Glenn
-----Original Message-----
From: Dale Ritzen [mailto:[log in to unmask]]
Sent: Tuesday, February 11, 2003 11:51 AM
To: [log in to unmask]
Subject: [TN] Moisture in Raw Boards
I, and our board suppliers, have looked through IPC-6011, 6012, 600, 610
and most of the other pertinent standards and cannot find an answer to
this
question:
How long should multi-layer printed circuit boards be left out in a
controlled ambient environment (standard factory temp/humidity) before
pre-baking the boards becomes necessary to dry out any accumulated
moisture in them? We would like to minimize potential board delamination
due to trapped moisture in the FR4 or polyamide layers (which can expand
rapidly when the board is placed through a reflow oven or solder wave).
Does anyone want to wade in on this one? We have identified a standard
for pre-baking IC components before use in this type of high-heat
environment, but cannot find any standard or specification pertaining
directly to PCBs themselves. I suspect it will have to take into account
the material used, number of layers, the definition of "standard factory
temp/humidity" and other things related to the board and the environment
it is stored in prior to use.
Any help in this regard would be appreciated.
Thanks!
Dale Ritzen
Quality Manager
Austin Manufacturing Services
9715A Burnet Road, Suite 500
Austin, TX 78758
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