Proceedings Article | 31 March 2006
Proc. SPIE. 6172, Smart Structures and Materials 2006: Smart Electronics, MEMS, BioMEMS, and Nanotechnology
KEYWORDS: Microelectromechanical systems, Gold, Electrodes, Metals, Capillaries, Particles, Tungsten, Dielectrics, Epoxies, Semiconducting wafers
Needle-like probe holds fine objects by adhesions without any holding devices. It can not pick up heavy and large objects, because the gravity rivals the adhesions. Referring to electrostatic chucks (ESCs), we fabricated two needle-like probes, of which adhesions are assisted by the electrostatic force, a monopole probe and a dipole probe. The former corresponds to monopolar ESCs and the latter corresponds to dipolar ESCs. By the assistant of an external electric power, both can pick up heavy and large objects. The monopole probe, which is a tungsten needle, can manipulate 40-80μm gold particles on a gold substrate as follows. The probe is lowered until it touches the particle. After 20-50V is applied between the probe and the substrate, the probe is pulled up. Then the particle is picked up with the probe. Once the particle is in the air, it stays at the tip of the probe even if the voltage is reduced to 0. For release of the particle, the probe is lowered until the particle touches the substrate and is pulled up without applying voltage. The dipole probe is made of two electrodes embedded in an epoxy resin. Different from the monopole probe, the dipole probe attract both conductive and dielectric objects over a gap. The probe jumps up a styrene particle of 3mm over the gap of 1mm by applying 2kV, and it jumps up a gold particle of 0.4mm over the gap of 0.5mm by applying 5kV. The release is possible only by turning the applying voltage off. As the gravity is greater than the adhesions, the objects adhered falls. The assistant electrostatic force of the monopole probe is Johnsen-Rahbek force same with the clamping force of monopolar ESCs, and that of the dipole probe is gradient force same with the clamping force of bipolar ESCs.
