P. Thiébaud

A New Fabrication Method for Borosilicate Glass Capillary Tubes with Lateral Inlets and Outlets

Abstract In this paper a new fabrication method for borosilicate glass capillary tubes is presented. As the interest in miniaturized total chemical analysis systems (μ-TAS) is increasing, the need for fluidic paths is growing and thus the study of microchannels, microtubes and microcolumns is an important topic of the microfluidic area. The capillary tubes presented here are fabricated by structuring and bonding three borosilicate glass wafers (7740 Corning Pyrex sR). Microchannels with lateral inlets and outlets have been successfully realized and well-defined size and shape have been obtained. Several capillary tubes with widths from 340 to 940 μm have been realized as well as different section shapes, which can be circular, elliptic or quasi-rectangular. The main fabrication steps and first characterizations are reported.

Microelectrode arrays for electrophysiological monitoring of hippocampal organotypic slice cultures

A three-dimensional platinum (Pt) microelectrode array embedded on a micromachined silicon (Si) substrate (porosity of 13%, via hole diameter of 40 /spl mu/m) has been developed. Electrodes are 35-/spl mu/m wide and 20-/spl mu/m high, spaced 200 /spl mu/m apart and arranged in an elliptic geometry. Integrated within a microperfusion chamber, the devices were used for stimulation and recording experiments of hippocampal slice cultures over a period of several days.

Advanced deep reactive ion etching: a versatile tool for microelectromechanical systems

Advanced deep reactive ion etching (ADRIE) is a new tool for the fabrication of bulk micromachined devices. Different sensors and actuators which use ADRIE alone or combined with other technologies such as surface micromachining of silicon are presented here. These examples demonstrate the potential and the design freedom of this tool, allowing a large number of different shapes to be patterned and new smart devices to be realized.

Electrostatic polysilicon microrelays integrated with MOSFETs

The fabrication and characterization of electrostatically-driven microrelays integrated together with IC components are presented. The mechanical part of the microrelays consists of a polysilicon-silicon nitride-polysilicon microbridge realized by sacrificial layer technology and allowing one to separate the actuation and the working circuit. The main operational parameters are actuation voltages in the 50 V to 75 V range depending on the beam lengths of the relays; switching frequencies up to 20 kHz with negligible electrical cross-talk between actuation and working port; a maximum measured frequency of 75 kHz without damaging the microrelay; a rise time of 4 /spl mu/s and a fall time of 1 /spl mu/s. First experiments in nitrogen atmosphere have shown that the relay is able to cycle over 10/sup 9/ times with no significant changes in its electromechanical properties.

Integrated circuit compatible electrostatic polysilicon microrelays

A low-power IC-compatible electrostatically driven microrelay is presented. The mechanical part of the microrelay consists of a polysilicon/silicon nitride/polysilicon microbridge realized by sacrificial layer technology. Its fabrication, operation up to 100 kHz and net switching voltages in the 1 to 10 V range are reported.

Microfabrication of Pt-tip microelectrodes

Abstract This paper describes the realization of Pt-tip microelectrodes by using microfabrication technology. The total height of these microelectrodes is 47 μm, of which the upper 20 or 2 μm, respectively, are exposed Pt tips with a curvature of 0.5 μm. In order to verify the tip opening, an electrochemical plating of thin-film Pt was used. This improves the visualisation of the tips in an SEM and allows us to ascertain the absence of any residual layer. The manufacturing process was assessed by SEM imaging and, in the case of large Pt-tip electrodes, also by an electrochemical evaluation.

Micromachined, fiber-optic based accelerometer with shutter modulation

A highly sensitive shutter modulated fiber-optic accelerometer has been fabricated and characterized. Its structure is based on a mass suspended by two side-by-side cantilever beams. A vertical shutter at the free end of the mass can move vertically in the optical path between two multimode optical fibers. Cantilever beams, mass, shutter and optical fiber grooves are fabricated by advanced deep reactive ion etching. The accelerometer is characterized using a supra luminescent diode. A resonance frequency above 1 kHz and a measurement range of /spl plusmn/5 g are measured. To demonstrate the potential of using an economic light emitting diode, an experiment with 2 /spl mu/W input power was performed. It resulted in a noise equivalent acceleration of 2 mg.