Neal,
See answers following your questions.
John Gulley - Process QE
INET Technologies
1255 W. 15th St
Plano, TX 75075
______________________________ Reply Separator _________________________________
Subject: [TN] Moisture Sensitive Components
Author: Neal W Driscoll <[log in to unmask]> at Internet
Date: 8/24/98 9:03 AM
We are an electronics manufacturing company starting to face the problems
of handling moisture sensitive components. I am interested in finding out
what other companies are doing in this area.
Our initial thoughts on the subject are that we will get the moisture
ratings from the manufactures and we will handle them and consume them
within the times and conditions outlined in J-STD-020. Right now, doing
something less than this does not appear to be an option.
Based on following the times and conditions outlined in J-STD-020 here are
some questions that come to mind:
- Once the original manufacture's packaging has been opened, is
re-packaging an option?
YES! 1st - Check with the component manufacturers packaging and storage
specifications. Identify what components will need storage. Identify
to what extent will you need vacuum assisted hardware, 1/8th-1/6th
dessicant packs, moisture barrier bags, humidity indicator card and
oxidation arrest paper. Re-use the component suppliers bags where
applicable. Date code the MBB.
Another key here is to minimize the human factor of touching the
components. Be sure to have specific front end instructions that ensure
minimal damage to the component periphery
With regards to hygroscopic dice, bake components on high (125°±5°) for
one hour and no more than once. I only recommended baking if the
Indicator card shows storage conditions to be excessive or it is known
the storage environment is harsh. The additional baking will only
proprogate the IMC.
- My understanding is that the shelf life on packaged components is
12 months. If we re-package, does the 12 month clock start
over, and if so, is there a document or standard that covers this part of
the issue?
Proper packaging will extend shelf life. Shelf life on
components, not fabs, is influenced by temperature
and humidity. Solderability degradation is induced by a condition
called IMC or intermetallic compound (Cu6Sn5).
- If re-packaging is an option, what are the different methods out
there and their pro's and cons?
See first answer.
- What are the logistics of handling these components from the stock
room to the production floor?
See first answer.
- If moisture sensitive components are going to be soldered by hand,
do we need to be concerned with the special handling issue, and if
not, is there a document or standard that covers this?
There may NOT be an issue with soldering by hand since the heat
applied is directed to one region at a time. However, Reflowing
the component that is not hermitically sealed and not properly
stored in poor humid conditions will probably initiate
popcorning, bond lift, die delamination, etc.
- Are there any other issues that might come up that go along with
moisture sensitive components?
- Are there any other industry standards that might help support and
document what we do?
If there is anything else I might need to be aware of, please throw it in.
Any information that anyone can supply will be a great help. Thanks for
your time.
Call me should you need additional info.
Neal Driscoll
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