IMPROVED MEASUREMENT OF SWAB HANDLE ELECTRICAL RESISTANCE TO AID IN CLEANROOM ELECTROSTATIC DISCHARGE CONTROL

摘要

Cleanroom swabs can pick up and generate electrostatic charge. These cleanroom swabs may subsequently contact sensitive structures during the manufacture of inductive or magneto - resistive read-write heads for data storage products. Electrostatic discharge can damage the read-write heads, as well as confuse robotics and accelerate particle deposition onto surfaces. Swab handle and swab tip resistances are important in this regard. To determine swab handle electrical resistivity, we have abandoned our earlier adaptation of the ESD Association Standard S11.11 surface resistance probe (Cooper, 1997) in favor of using conformal conductive coatings for the test electrodes. The problems with the original approach are described, along with the improvements offered by this revised approach. Swab handle resistivities (ohm/cm) were measured with a precision such that the standard deviations were about 10% of the means.