Danger of high voltage ground short in ESD protection scheme?

[[email protected]]

Hi,

A conductive surface wired to ground and to worker touches sensitive
semiconducting components. Some components create high voltage. If
ground surface touches high voltage comonents, worker is protected by
megaohm resistor in wrist strap, but other components lie between high
voltage component and ground wire! Thus, sensitive semiconducting
components will be destroyed by great current from high voltage in
ground short. Assume aluminum is the conducting surface. Could
another surface material still dissapate ESD to ground but prevent
great current from high voltage discharge? Thanks.

 

[[email protected]]

Hi,

A conductive surface wired to ground and to worker touches sensitive
semiconducting components. Some components create high voltage. If
ground surface touches high voltage comonents, worker is protected by
megaohm resistor in wrist strap, but other components lie between high
voltage component and ground wire! Thus, sensitive semiconducting
components will be destroyed by great current from high voltage in
ground short. Assume aluminum is the conducting surface. Could
another surface material still dissapate ESD to ground but prevent
great current from high voltage discharge? Thanks.

It has occured to me that it is best to work on the conductive surface
only when no voltage is applied, and to insulate components from ground
surface (and thus from other semiconductor components) when applying
voltage to those components, as the worker never touches such live
components anyway. However, after voltage application ends, the
component must be grounded away from the semiconducter components, and
only then placed on the same surface.

Such a conducting, grounded surface could be aluminum, but I see so
called "anti-static mats" for sale. How are these any different from
ordinary conductors? Do they have resistance to prevent great current?
Thanks.

 

[[email protected]]

It has occured to me that it is best to work on the conductive surface
only when no voltage is applied, and to insulate components from ground
surface (and thus from other semiconductor components) when applying
voltage to those components, as the worker never touches such live
components anyway. However, after voltage application ends, the
component must be grounded away from the semiconducter components, and
only then placed on the same surface.

Such a conducting, grounded surface could be aluminum, but I see so
called "anti-static mats" for sale. How are these any different from
ordinary conductors? Do they have resistance to prevent great current?
Thanks.

Hmm... grounded aluminum is perhaps too conductive and would create to
great a current ground in contact with a previously statically charged
component. Thus "anti-static mats" must have internal resistance. Can
anybody verify this? Thanks.

 

[Michael A. Terrell]

Hmm... grounded aluminum is perhaps too conductive and would create to
great a current ground in contact with a previously statically charged
component. Thus "anti-static mats" must have internal resistance. Can
anybody verify this? Thanks.

http://www.charleswater.co.uk/tech.asp
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[[email protected]]

http://www.charleswater.co.uk/tech.asp
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Hi,

Thanks for the link. (Which states work-surface should be between
1,000,000 and 1,000,000,000 ohms resistance.)