Institute of Fundamental Technological Research

The movement of a micro cantilever was detected via a self constructed portable data acquisition prototype system which integrates a linear array of 32 1D amorphous silicon position sensitive detectors (PSD). The system was mounted on a microscope using a metal structure platform and the movement of the 30 µm wide by 400 µm long cantilever was tracked by analyzing the signals acquired by the 32 sensor array electronic readout system and the relevant data algorithm. The obtained results show a linear behavior of the photocurrent relating X and Y movement, with a non-linearity of about 3%, a spatial resolution of less than 2 µm along the lateral dimension of the sensor as well as of less than 3 µm along the perpendicular dimension of the sensor, when detecting just the micro-cantilever, and a spatial resolution of less than 1 µm when detecting the holding structure.

amorphous semiconductors, silicon, devices, systems

The position of a 40 μm wide by 400 μm long cantilever in a microscope was detected by a 32 lines array of 1D amorphous silicon position sensitive detectors (PSD). The sensor was placed in the ocular used for the CCD camera of a microscope and the alignment, focusing and positioning of the cantilever was achieved using the X–Y–Z translation table of the microscope that has a micrometer resolution controller. In this work we present results concerning the micro positioning of a cantilever and its holding structure through the reflected light that is detected by 1D/3D psd and converted to an analog signal proportional to the movement. The signal given by the 32 sensor array was analyzed directly without any electronic readout system or data algorithm. The obtained results show a linear behavior of the photovoltage relating X and Y movement, a non-linearity less than 2% and spatial resolution of 600 μV/μm.

Amorphous Semiconductors, Silicon, Devices

Polymeric films with low surface energy were investigated as a solution to decrease adhesion at the gripping surface of the micromanipulator. Eight polymeric films were investigated. The polymeric films were tested by an AFM (with standard silicon cantilever in normal environmental conditions) and by a triboscope under controlled conditions with varied substrate temperature. From this number of polymers, three of them: methylsilicone resin and methylphenylsilicone – all in aromatic hydrocarbon solution, were selected to coat the grippers due to their very low roughness (35–55 nm). One of samples was selected as an example of a polymer with a catalyst. The grippers were coated by dipping the working arms (single-crystal silicon) to the solution of polymer and then dried on the heater or in the environment conditions correspondingly. Several gripping experiments were performed to test the functionality of the coatings. Different objects – algae shells (∼250 μm) and silicon parts (5–100 μm) – were manipulated with uncoated and coated grippers. Influence of the polymer coating on the stiction effect was tested.

Adhesion, Microgripping, Polymer coatings

This work is focused on the design and the fabrication of an electrostatically driven microgripper for blood vessel manipulation. The goal is to realise a new system for the automated study of blood vessel wall contraction forces. Our device is based on an electrostatic comb-drive actuated silicon microgripper whose tips can be inserted into blood vessel samples providing isostatic conditions during the test and allowing contraction force measurement in the range of a few mN. A major innovation of the tool compared with existing devices is the capability of scaling down the diameter of the vessels that can be tested, reaching an internal diameter of 50 μm. In the paper a brief overview of the state of the art is presented, design details, simulations results and steps of the fabrication process are described.

Micromanipulation, Bio-MEMS, Microgripper, Comb drive actuators