A new magnetically levitated wafer transport system is developed for the semiconductor fabrication process to get rid of the particle and oil contaminations that normally exist in conventional transport systems. The transport system consists of levitation, stabilization tracks, and a propelling system. Stabilities needed for levitation in the transport system are achieved by an antagonistic property produced in the tracks and using a simple feedback control. The continuous propelling force is obtained by sending specific current patterns to the propulsion coils. The dynamic model of the transport system is presented and analyzed.
"P.R. Southworth  and D. Belnap  both developed electromagnetic levitation transport systems for contactless transmission of semiconductor materials. K. H. Park   developed a new type of electromagnetic levitation silicon wafer transmission system to solve the pollution problems in traditional contact transport. However, electromagnetic levitation is only applicable to the conductor or semiconductor materials with high conductivity. "
[Show abstract][Hide abstract] ABSTRACT: Re-configurability and scalability are important
properties of smart non-contact conveyors. The paper studies
smart conveyors. It concentrates on levitation methods; it
makes a comprehensive survey on levitation technologies that
are currently most active. A conclusion is made that air
levitation is well suited to smart conveyors. Furthermore, an
overview of the movement mechanisms on air levitation
platforms is presented; the various advantages of these
technologies are reviewed here and associated scalability
properties are detailed. This provides a reference for selecting
a reliable movement mechanism for future smart conveyors.
15th IEEE International Conference on Scalable Computing and Communcations, Beijing China; 08/2015
"To perform planar displacements a variety of actuation methods have been developed including electrostatic actuators , electromagnetic actuators  and air jets . These methods enable to manipulate the objects with no direct contact which avoids damages of fragile components such as electronic cards . "
[Show abstract][Hide abstract] ABSTRACT: One of the greatest challenge in microrobotics is the development of miniaturized smart surfaces for a high speed conveying and positioning of micro-objects. This paper proposes a new approach where objects are situated at the air/liquid interface and are manipulated through magnetic fields. It demonstrates that a good repeatability and a high speed can be obtained. A physical modeling is presented to analyze the dynamic behavior of the micro-object. Experiments are performed to determine the physical parameters of the model and to attest the good repeatability of the motion for an object of size 100x90x25µm 3 . A good agreement between the physical model and the experimental measurement is demonstrated. Since the velocity of the micro-object can be 10 times higher at the air/liquid interface than in the liquid this approach represents a promising solution to design smart surfaces for a high throughput conveying of micro-objects.
International conference on robotics and intelligent systems; 09/2014
"In the electromagnetic levitation, the levitation force comes from a magnetic field generated by permanent, electro -or superconducting magnets. The electromagnetic levitation was employed for studying crystallization processes and silicon wafer transport systems (see Davis, 1997; Park et al. 1996; Motokawa et al. 1998; Kang et al. 2003 and papers cited therein). However, the use of such levitation scheme is limited to materials with high electrical conductivity. "
[Show abstract][Hide abstract] ABSTRACT: We investigate analytically and numerically trapping of submicron aerosol particles in a three-dimensional quadrupole acoustic chamber having hyperbolical configuration. The particle trajectories are described by the Langevin equation accounting for particle random Brownian motion. The particle trapping efficiency is investigated for a range of acoustic field parameters and particle properties. It is shown that submicron diffusive particles can be trapped in a small region near the chamber center. The effect of Brownian motion is to broaden the trapping region. The dimensions of the trapping region can be reduced by increasing the acoustic strength parameter.
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