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| Faraday cage protects shelf contents
against ESD |
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Desiccator Grounding
All Terra desiccators made of
static-dissipative PVC feature grounding terminals on a standard basis.
The surface resistivity of this material (around 107 ohms/square) allows controlled
dissipation of static charges from any surface in the cabinet,
including shelves. Conductive grounding connections safely direct
charges to a grounding terminal (standard on SDPVC cabinets; order
separately for acrylic cabinets below).
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Desiccator
Grounding
Includes installation of conductive grounding tape and grounding
terminals. Charge is per chamber; quantity should correspond to number
of chambers affected. (Included standard on cabinets made of
static-dissipative PVC.)
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| Warning:
Grounded conductive connectors can create sparking, which can damage
sensitive materials. Use of a resistor (not included) is recommended. |
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1. Static-Dissipative PVC
Acrylic, the most common plastic used in storage enclosures, is a
prolific static generator. The act of cleaning an acrylic desiccator
with a cleanroom wiper is enough to generate surface charges that can
discharge onto semiconductor components. One way to avoid potentially
disastrous static damage is to select Static-Dissipative PVC.
This material not only dissipates static charges safely,
but it also eliminates the particle attraction that static charges
create. Surfaces stay clean, inside and out, making this material
perfect for use in Class 1 cleanrooms.
Because static-dissipative PVC is transparent and highly
durable, it can be used in place of acrylic in nearly any application,
desiccators included. It features a surface resistivity of
approximately 107 ohms per
square, placing it in the "dissipative range". It is completely
noncontaminating—with no measurable outgassing—and it resists a wide
range of chemicals.
Note: To protect
Static-Dissipative PVC surfaces, desiccators made of this material must
include stainless steel shields installed at the bottom of each chamber.
2. Self-Balancing Ionizing
Nozzles
>By ionizing nitrogen molecules as they pass through the desiccator
plenum wall, ionizing nozzles neutralize electrostatic charges on all
interior surfaces. They provide practical ESD control for charged
nonconductive materials, which cannot dissipate charges to ground. And
because they eliminate static attractive forces, they help control
contamination: in a statically neutral environment, any airborne
particles that enter a desiccator are more likely to remain airborne
and to be purged out of the cabinet.
3. Conductive Shelves, Shields
and Trays
For smaller components that can be stored on shelves, Terra's grounded
stainless steel shelving provide a 100% ESD-safe enclosure.
As the illustration depicts, grounded conductive plates
(such as shelves) create a Faraday cage that prevents penetration of
static charges. Because these conductive units are removable, they also
protect your sensitive components from ESD as you transport them from
one location to another.
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By dissipating static charges, Static-Dissipative PVC also
eliminates particle attraction, providing animportant
contamination-control benefit! |
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