Micro-Fluidics Interest Group

In the column on the right you will find useful information about the manufacturing of micro-fluidic devices.

Below you will find recent posts on the 4M Association which are considered to be of interest to the Micro-fluidics Interest Group.

electro-discharge machining

Electric discharge machining (EDM), sometimes colloquially also referred to as spark machining, spark eroding, burning or die sinking, is a manufacturing process whereby a wanted shape of an object, called workpiece, is obtained using electrical discharges(sparks). The material removal from the workpiece occurs by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage. One of the electrodes is called tool-electrode whereas the other is called workpiece-electrode. When the distance between the two electrodes is reduced, the intensity of the electric field in the volume between the electrodes is expected to become larger than the strength of the dielectric and therefore the dielectric breaks allowing some current to flow between the two electrodes. A collateral effect of this passage of current is that material is removed from both the electrodes. Once the current flow stops (or it is stopped - depending on the type of generator), new liquid dielectric should be conveyed into the inter-electrode volume enabling the removed electrode material solid particles (debris) to be carried away and the insulating proprieties of the dielectric to be restored.

wet chemical etching

Etching is used to chemically remove layers from the surface of a wafer during manufacturing. For many etch steps, part of the wafer is protected from the etchant by a "masking" material which resists etching. In some cases, the masking material is photoresist which has been patterned using photolithography. Other situations require a more durable mask, such as silicon nitride. The wafer can be immersed in a bath of etchant, which must be agitated to achieve good process control. Different specialised etchants can be used to characterise the surface etched. Some wet etchants etch crystalline materials at very different rates depending upon which crystal face is exposed. In single-crystal materials, this effect can allow very high anisotropy.

plasma etching

Plasma etching is a form of plasma processing used to fabricate integrated circuits. It involves a high-speed stream of glow discharge (plasma) of an appropriate gas mixture being shot (in pulses) at a sample. The plasma source (known as etch species) can be either charged (ions) or neutral (atoms and radicals). During the process, the plasma will generate volatile etch products at room temperature from the chemical reactions between the elements of the material etched and the reactive species generated by the plasma. Eventually the atoms of the shot element embed themselves at or just below the surface of the target, thus modifying the physical properties of the target.

ion etching

Reactive ion etching (RIE) is an etching technology used in microfabrication. It uses chemically reactive plasma to remove material deposited on wafers. The plasma is generated under low pressure (vacuum) by an electromagnetic field. High-energy ions from the plasma attack the wafer surface and react with it.

stereolithography

Stereolithography is a common rapid manufacturing and rapid prototyping technology for producing parts with high accuracy and good surface finish. Stereolithography is an additive fabrication process utilizing a vat of liquid UV-curable photopolymer "resin" and a UV laser to build parts a layer at a time. On each layer, the laser beam traces a part cross-section pattern on the surface of the liquid resin. Exposure to the UV laser light cures, or, solidifies the pattern traced on the resin and adheres it to the layer below. After a pattern has been traced, the elevator platform descends by a single layer thickness, typically 0.05 mm to 0.15 mm (0.002" to 0.006"). Then, a resin-filled blade sweeps across the part cross section, re-coating it with fresh material. On this new liquid surface the subsequent layer pattern is traced, adhering to the previous layer. A complete 3-D part is formed by this process. After building, parts are cleaned of excess resin by immersion in a chemical bath and then cured in a UV oven.

4th congress on Micro and Nano Manufacturing

Micromachines - Supporting the 4M Association

MDPI - Supporting the 4M Association

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Micro-Fluidics Interest Group

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