Sylwester Bargiel

Towards micro-assembly of hybrid MOEMS components on a reconfigurable silicon free-space micro-optical bench

The 3D integration of hybrid chips is a viable approach for the micro-optical technologies to reduce the costs of assembly and packaging. In this paper a technology platform for the hybrid integration of MOEMS components on a reconfigurable silicon free-space micro-optical bench (FS-MOB) is presented. In this approach a desired optical component (e.g. micromirror, microlens) is integrated with a removable and adjustable silicon holder which can be manipulated, aligned and fixed in the precisely etched rail of the silicon baseplate by use of a robotic micro-assembly station. An active-based gripping system allows modification of the holder position on the baseplate with nanometre precision. The fabrication processes of the micromachined parts of the micro-optical bench, based on bulk micromachining of standard silicon wafer and SOI wafer, are described. The successful assembly of the holders, equipped with a micromirror and a refractive glass ball microlens, on the baseplate rail is demonstrated.

Micromachined array-type Mirau interferometer for parallel inspection of MEMS

We present the development of an array type of micromachined Mirau interferometers, operating in the regime of low coherence interferometry (LCI) and adapted for massively parallel inspection of MEMS. The system is a combination of free-space micro-optical technologies and silicon micromachining, based on the vertical assembly of two glass wafers. The probing wafer carries an array of refractive microlenses, diffractive gratings to correct chromatic and spherical aberrations and reference micro-mirrors. The semitransparent beam splitter plate is based on the deposition of a dielectric multilayer, sandwiched between two glass wafers. The interferometer matrix is the key element of a novel inspection system aimed to perform parallel inspection of MEMS. The fabricated demonstrator, including 5 × 5 channels, allows consequently decreasing the measurement time by a factor of 25. In the following, the details of fabrication processes of the micro-optical components and their assembly are described. The feasibility of the LCI is demonstrated for the measurement of a wafer of MEMS sensors.

A simple method for quality evaluation of micro-optical components based on 3D IPSF measurement.

This paper presents a simple method based on the measurement of the 3D intensity point spread function for the quality evaluation of high numerical aperture micro-optical components. The different slices of the focal volume are imaged thanks to a microscope objective and a standard camera. Depending on the optical architecture, it allows characterizing both transmissive and reflective components, for which either the imaging part or the component itself are moved along the optical axis, respectively. This method can be used to measure focal length, Strehl ratio, resolution and overall wavefront RMS and to estimate optical aberrations. The measurement setup and its implementation are detailed and its advantages are demonstrated with micro-ball lenses and micro-mirrors. This intuitive method is adapted for optimization of micro-optical components fabrication processes, especially because heavy equipments and/or data analysis are not required.

Wafer-Level Fabrication of Microcube-Typed Beam-Splitters by Saw-Dicing of Glass Substrate

This letter reports on the development of an integrated micro-optical beam splitter that can be array-arranged. The proposed wafer-level fabrication, based on 45 ° saw-dicing of glass substrates, allows rapid and low-cost processing. In particular, it leads to high compactness and possibility of wafer-level alignment/assembly, suitable for vertically integrated imaging micro-instruments. The device, including additional out-of plane reflection for extraction of sensing beam, can be as small as 1 mm3.

A micro-assembly station used for 3D reconfigurable hybrid MOEMS assembly

Micro-assembly has been identified to be a critical technology in the microsystems technology and nanotechnology. The increasing needs of MOEMS (micro-opto-electro- mechanical systems) for the microsystems conducts to development of new concepts and skilled micro-assembly stations. This paper presents a 3D micro-assembly station used for the reconfigurable free space micro-optical benches (RFS-MOB) which are a promising type of MOEMS. The designed parts of RFS-MOB are assembled by using the developed micro-assembly station. Experimental results are shown and validate the effectiveness of the micro-assembly station and the micro-assembly strategies.

On-Chip Scanning Confocal Microscope with 3D MEMS Scanner and VCSEL Feedback Detection

We propose an original approach of a miniature scanning confocal microscope that uses two electrostatic scanners with microoptical lenses. For this chip-scale microscope, we demonstrated the use of optical feedback of VCSELs laser as an active detection. The z-axis scanner will provide a vertical motion of the first microlens in the range of 100 mum, controlling the focal length of the objective. Raster scanning (30 mum in both directions) of a specimen by the focused illumination spot will be implemented by actuating of second microlens by x-y-axis scanner.

Optical Design of a Vertically Integrated Array-type Mirau-based OCT system

The presented paper shows the concept and optical design of an array-type Mirau-based OCT system for early diagnosis of skin cancer. The basic concept of the sensor is a full-field, full-range optical coherence tomography (OCT) sensor. The micro-optical interferometer array in Mirau configuration is a key element of the system allowing parallel imaging of multiple field of views (FOV). The optical design focuses on the imaging performance of a single channel of the interferometer array and the illumination design of the array. In addition a straylight analysis of this array sensor is given.

Swept Source Optical Coherence Tomography Endomicroscope Based on Vertically Integrated Mirau Micro Interferometer: Concept and Technology

This paper presents a concept of an endomicroscope for an early detection of neoplastic lesions in the human stomach tissue, based on the swept source optical coherence tomography (SS-OCT) and a measurement probe with integrated Mirau micro interferometer. The system consists of pigtailed illumination and detection blocks, connected via a Gradient Index (GRIN) lens collimator to a micro-opto-electro-mechanical systems (MOEMS) measurement probe (4 mm × 4 mm × 20 mm). The technology of Mirau micro interferometer is based on vertical multi-wafer bonding approach. The MOEMS probe is intended to be mounted on a continuum robot arm to perform in vivo microscopy of stomach tissues. First, the optical design of the SS-OCT endomicroscope is described, including an analysis of sensitivity. Then, we focus on the fabrication technologies and optical characterization of a key component of the Mirau micro interferometer, i.e., monolithically integrated focusing glass lens. SS-OCT endomicroscope will provide a fast axial scanning of tissues with A-scan sweep rate of 110 kHz, offering the axial resolution of 5.2 μm and the lateral resolution of 10.2 μm.

Next-generation test equipment for micro-production

The paper introduces different approaches to overcome the large ratio between wafer size and feature size in the testing step of micro production. For the inspection of Micro(Opto)ElectroMechanicalSystems (M(O)EMS) a priori information are available to optimise the inspection process. The EU-project SMARTIEHS develops a new concept for high volume M(O)EMS testing. The design of the test station and the fabrication of the first components are presented and the advancements compared to the state of the art are introduced within the following fields: micro-optical interferometer design, micro-optical production, smart-pixel camera and mechanical design. Furthermore the first demonstrators are introduced and experimental results are presented.

A micromachined silicon-based probe for a scanning near-field optical microscope on-chip

The novel concept of an integrated scanning near-field optical microscope on-chip (SOMOC) has been presented. SOMOC consists of a micromachined cantilever probe and an emission-detection device realized by the use of a vertical-cavity surface-emitting laser (VCSEL). The construction and the first technological results of the silicon probe with a light transparent SiO2 tip have been described. The basic mechanical properties of the probe have been determined by stroboscopic interferometry.