Monique Dilhan

Integrated LC Filter on Silicon for DC–DC Converter Applications

The integration of passive components on silicon for future dc-dc converter applications is still a challenging area of research. This paper reports the microfabrication of a fully integrated filter containing a spiral inductor on top of a 3-D capacitor. A thin magnetic shielding layer is introduced between the two components demonstrating that losses caused by the inductor in the capacitor area are reduced, thus increasing the maximum working frequency of the whole component. The fabricated filter was characterized in a test circuit (buck-type converter).

Experimentation of electrostatically actuated monochip micropump for drug delivery

The objective of the MICROMED CNRS project is the design of a complete microsystem usable in the treatment in vivo of hypertensives. The microsystem which corresponds with this objective includes different elements such as pressure sensors, a drug reservoir, a monitoring chip and a drug delivery system that necessitates the use of a dosing micropump able to deliver daily does of few microliters in several shots. We will focus here on the micropump:microfabrication technology, assembly and test. The fact that the fluid actuating membrane, the input and output fluid gates, and the two passive microvalues are together on a single silicon chip of 1 cm3 area makes this pump original. The fabrication technology combines the techniques of microelectronics and MEMS: micromachining for the square membrane and the fluid gates, sacrificial oxide layers and LPCVD polysilicon deposition for the microvalves. The assembly of the different parts is based on existing techniques like anodic bonding, gluing with adhesive films...we have investigated the fabrication of the micro pump with an electrostatic actuation. Tests are in progress for the first prototypes on a specific experimentation set- up in order to: (i) study the flowing of different fluids into the pump, (ii) study the directionality of the valves by plotting the flow rate/pressure (Phi) (P) diagram, (iii) study the pump functionality.

Reliability of microsystems based on a failure mechanism approach

Compactness, complexity of the interconnections and specific packaging, which are characteristics of Microsystems (MEMS), rule out the use of statistical procedure to assess reliability in space applications. Predictable reliability is the method recommended in this paper that uses a similar approach as CALCE already did for hybrid and microelectronic circuits. This method based on a failure mechanism approach is recalled at first and an example to illustrate this procedure based on the evolution of material crystal properties under radiation is presented.

Comparisons of the new thick negative resist to Su8 resist

This work deals with recent advances in the microfabrication process technology for medium to high-aspect ratio structures fabricated by UV photolithography using different kinds of photoresists. The resulting structures were used as molds and will be transformed into metal structures by electroplating. Two types of photoresists are compared: epoxy-based (negative) SU-8 and acrylate-based (negative) Intervia BPN. This work was prompted by the need to find an alternative to SU-8 photoresist which is difficult to process and remove after electroplating. The results presented in this paper open up new possibilities for low-cost processes using electroplating in MEMS applications.

Micro-interconnection technology suitable for RF-NEMS varactors elaboration

This paper deals with the development of a micro-interconnection technology suitable for the elaboration of RF-NEMS (Nano-ElectroMechanical Systems) varactors. It aims to present an extension of RF MEMS concept into nano-scale domain by using multi-walled carbon nanotubes (MWCNT) as movable part instead of micrometric membranes into reconfigurable passive circuits for microwave applications. For such a study, horizontal configuration of the NEMS varactors has been chosen and is commented. The technology is established to fulfill several constraints, technological and microwave ones. As far as technological requirements are concerned, specific attentions and tests have been carried out to satisfy: • Possible and later industrialization. No e-beam technique has been selected for RF NEMS varactor elaboration. Lateral MWCNT growth performed on a Ni catalyst layer, sandwiched between two SiO2 layers, showed feasibility of suspended MWCNT beam. • High thermal budget, induced by the MWCNT growth by CVD (Chemical Vapor Deposition), at least to 600°C. All the dielectric and metallic layers, required to interlink the nano world with the micrometric measurements one, have been studied accordingly. Consequently, the order of the technological steps has been identified. About microwave and actuation specifications (targeted close to 25V), the minimization of losses and actuation voltage implies large layers thicknesses compared to the CNT diameter. Several specific technological issues are presented in this paper, taking care of both technological and microwave compatibility to go toward RF NEMS varactors elaboration.

Micro inductors using low temperature fabrication processes for integrated DC-DC microconverters

We present in this paper trends and technologies for the integration of inductors for DC-DC microconverters. In particular, we present the fabrication steps of different structures as a function of the application: planar inductors for low power consumption, and 3D magnetic inductors for higher power. These devices are achieved using low temperature fabrication processes based in photolithography or and electroplating techniques.