Electrostatic discharge (ESD) problem resulting from charges on wafers is a serious
concern in IC manufacturing processes. Even though micro-environments, such as a
FOUP or a SMIF pod, provide path to ground to conduct away charges on wafers,
this method cannot remove charges on the insulative features on a work-in-process
wafer. In this study, we integrated an ionization module to a FOUP purge system to
neutralize charges on wafers. With a full load of wafers, ionized nitrogen entered the
FOUP and effectively reduced the wafer charge level from 1,000 v/cm to 100 v/cm
within 5 minutes. The effectiveness of neutralizing charges and ease of integrating
with currently available purge facility enable this method a promising way to help
reduce wafer charges, thus reduce the possibility of ESD damages to ICs on wafer.
The same idea can be applied to reduce charges on reticles in a recticle pod.
Improving the lifetime of conjugated polymer-based devices that undergo repeated cyclic electrical stimulation, such as
actuators, is important for commercialization. In general, conjugated polymers are contacted by metal electrodes; strain
from volume change can cause the polymers to delaminate, which slowly deteriorates performance or results in sudden
device failure. In this paper, we used polypyrrole on gold to investigate methods for improving adhesion. Gold electrode surfaces were roughened through electroplating, and the adhesion of polypyrrole deposited on these surfaces was tested upon extended electrochemical cycling. Delamination was quantified using a tape test and followed versus cycle number until the polypyrrole was removed or was no longer electroactive. Untreated control surfaces were also monitored. The most effective method for improving adhesion was a 1 μm thick layer of electroplated Au, which
extending the lifetime of the interface beyond the 50,000 cycle lifetime of PPy in aqueous solutions.
We present the use of electroactive polymer actuators as components of a biolab-on-a-chip, which has potential applications in cell-based sensing. This technology takes full advantage of the properties of polypyrrole actuators as well as the wide range of CMOS sensors that can be created. System integration becomes an important issue when developing real applications of EAP technologies. The requirements of the application and the constraints imposed by the various components must be considered in the context of the whole system, along with any opportunities that present themselves. In this paper, we discuss some of these challenges, including actuator design, the use of complementary actuation techniques, miniaturization, and packaging.
Polypyrrole/gold bilayer microactuators are being developed in our laboratory for biomedical applications such as microvalves. To fully open and close the valves, the bilayer hinges must be able to rotate between 0° and 180° within a few seconds against external forces. The layer thicknesses and hinge lengths must therefore be properly designed for the application. However, existing models fail to predict the correct behavior of microfabricated PPy/Au bilayer microactuators. Therefore, additional experimental data are needed to correctly forecast their performance. Bilayer actuators were fabricated with ranges of PPy thicknesses and hinge lengths. Bending angles were recorded through a stereomicroscope in the fully oxidized and reduced states. Isometric forces exerted by the hinges were measured with a force transducer, the output of which was read by a potentiostat and correlated with the applied potentials.