Deep-etch Lithography Research Articles

Fabrication and Packaging Technologies of Love-wave-based Microbalance for Fluid Analysis

Quartz crystal microbalance (QCM) based techniques have been developed for years to address various kinds of biochemical analyses in liquid media. An alternative to this approach based on guided acoustic shear waves, the socalled Love wave devices, has been proved to allow for increasing gravimetric sensitivity. However, this approach reveals more complicated to implement as the surface on which reactions are achieved is the same as the one used for electrical connection. As a consequence, a microfluidic set-up must be implemented to prevent unwanted interactions between the corresponding areas (IDTs and propagation path). The main issue when using SAW Sensors for in-liquid biochemical analyses [1-4], especially in a commercial objective, is the development of a reliable and reproducible fluidic system [5] meeting the main following requirements: i) low acoustic leakage. ii) chemically inert to biological samples. iii) reproducible fabrication at the wafer scale level.In the present work we explore the use of the SU-8 epoxy-based photoresist combined with silicon or quartz machined covers for the fabrication of this fluidic circuit. A first structure is fabricated using deep etch lithography, the cover is then glued to the remaining SU-8 structure using a thin glue layer. The packaging system prevents covering the IDTs with liquids and defines the sensing area in the region in-between the IDTs. Once the fabrication achieved, we evaluate the velocity and propagation loss using a network analyzer to measure the influence of the proposed packaging approaches on the principal wave characteristics.

Novel Optical Backplane for Automotive Applications

Abstract Deep etch lithography like the LIGA technique combines high precision and mass production capability. It is a well suited candidate for precision micro-optics because of its unique characteristic which allows the fabrication of optical and mechanical micro-elements in the same substrate. In this paper we will focus on a novel alignment tolerant optical backplane approach well suited for automotive applications that is based on a hybrid integration of guided wave and free space micro-optics by the LIGA technique.

The study of LIGA technique at NSRL

The activity of LIGA technique was started in the fall of 1993 at National Synchrotron Radiation Laboratory (NSRL), some primary results have been obtained. Micro gearwheels were produced by deep-etch lithography using Hefei light source. The largest diameter of gearwheel is 200 μm, the smallest one only 35 μm, both with thickness of 50 μm. The first metallic structure of nickel was fabricated recently. The mask used in experiments was made by ourselves, it is a composite of kapton membrane as a mask blank, and gold as an absorber.

Deep etch lithography at LURE-D.C.I. storage ring

LIGA technique has proved to be a powerful tool for micro-fabrication mass production. French laboratories (LURE, L2M, LPMO) gathered to introduce this new technology at LURE facilities. In this paper are described the different steps of the deep etch lithography process including mask realization and first pseudo-tridimensional resist structures are shown

Three-dimensional microfabrication using synchrotron radiation

Abstract For fabricating microstructures with extreme structural heights a technology has been developed which is based on deep-etch lithography and subsequent replication processes. A particularly high precision is achieved when the lithographic process is carried out by means of synchrotron radiation. Electroforming and molding processes are used for the replication of microstructures from a large variety of materials. The field of application comprises sensors, electrical and optical microconnectors, components for fluid technology, micromechanical components, microfiltration systems and novel composite materials.

Fabrication of a planar grating spectrograph by deep-etch lithography with synchrotron radiation

Abstract A three-layer resist system has been developed which can be used for light guiding. By structuring these layers with deep-etch X-ray lithography, high-precision multimode lightguide components with a relatively low attenuation can be produced. As a first example, a planar grating spectrograph with a self-focusing reflection grating has been fabricated together with fibre-fixing grooves. The spectro-graph shows an excellent dispersion of the light as well as a low cross-talk between the channels.

Description of microstructures in LIGA-technology

The LIGA process is based on deep-etch lithography with synchrotron radiation, electroforming and plastic molding. This process allows three-dimensional microstructures to be fabricated from a variety of materials. By means of a sacrificial layer technique freely movable oscillating and rotating microstructures have been fabricated. The potential of the LIGA technology is demonstrated by the presentation of components for integrated optics, bandpass and highpass filters for the far infrared, acceleration sensors, and microgears.

Prospective nonlithographic applications of a synchrotron radiation source for deep-etch lithography

It is pointed out that the performance of superconducting storage ring synchrotron radiation sources designed for deep-etch lithography like the source KSSQ planned at Karlsruhe is much superior to that of typical thin film lithography sources and comes close to that of first and second generation synchrotron radiation sources. Therefore, the range of applications of such machines exceeds the original design goal by far and includes many of the important synchrotron radiation methods based on diffraction, absorption, and fluorescence excitation, as well as foreseeable production methods. Thus, these machines may become a new class of sources of their own.