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A humidity indicator card (HIC) is a card on
which a moisture-sensitive chemical is
impregnated such that it will change color
when the indicated relative humidity is
exceeded. This item is an inexpensive way to
quantify relative humidity levels inside
sealed packaging. They are available in many
configurations and used in many applications,
especially military and semiconductor.
The most common humidity indicator cards
change color from blue (less than indicated RH
level)to pink (greater than indicated RH
level). Base chemical is cobalt (II)
chloride). United States Military
Specification Mil-I-8835A is the governing
specification for a humidity indicator card.
The humidity indicator card is also specified
for use in J-STD-033 which is the standard for
Handling, Packing, Shipping and Use of
Moisture/Reflow Sensitive Surface Mount
Devices, also known generically as
semiconductors. This is a joint standard
developed by the Joint Electron Device
Engineering Council and IPC and is used in
semiconductor packaging.
Humidity Indicator Card
History
The need for an easily read humidity indicator
that could not be damaged by vibration was
identified during World War II. Rear Admiral
Welford C. Blinn, at that time the Commander
of the USS Pope, became concerned about the
poor condition of the weapons and ammunition
arriving in the Pacific Theater. High humidity
in the South Pacific, coupled with poor
packaging methods, was causing corrosion and
moisture damage. A significant amount of
ordinance was arriving in an unstable, and
sometimes dangerous, condition. Following the
end of the war R. Admiral Blinn was assigned
to Washington, D.C. where he had the use of a
research lab. There he developed the concept
for the first color change humidity indicator,
a simple “go/no-go” method of
monitoring humidity.
In the late 1940’s, Relative Humidity in
the range of 30-35% was the concern because
this is when corrosion can begin. For 50
years, industrial and military applications
for color change humidity indicators were the
primary market for these products. R. Admiral
Blinn founded Humidial Corporation in 1948
Acquired by Süd-Chemie, Inc. in 1989 to
commercialize humidity indicators.
In the mid-1980’s decedents of R.
Admiral Blinn, began working with manufactures
of semiconductors to identify and resolve the
problem of “pop corning”. It was
determined that the solder mounting of
semiconductors, also known as devices, onto
boards can cause "pop corning" of
certain types of surface mount packages if
they have been improperly stored or handled.
This package delamination occurs as excessive
moisture within the package expands as a
result of the rapid thermal changes
experienced during solder mount operations. As
a result an industry wide standard for
packaging of semiconductors was released in
1989. This standard, EIA 583, called for the
use of humidity indicator card that would
indicate as low as 10%. Adherence to proper
storage and handling methods immediately
reduced the number of failures in the
semiconductors, but over the years it became
apparent that even humidity levels under 10%
were detrimental to the devices. Once again,
the Joint Electron Device Engineering Council
(JEDEC), now the standards body for
semiconductor packaging, went to the decedents
of R. Admiral Blinn to determine the
feasibility of making a 5% color change
humidity indicator. In April 1999, J-STD-033
was released with a 5, 10, 15% color change
indicator card specified.
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