Micron-scale flexible and thin film circuits

June 11, 2014 // By Jean-Pierre Joosting
Metrigraphics have achieved large-scale production of micron-scale flexible circuits six or more layers high with traces (circuit lines) as narrow as 3 microns (11.81 x 10-5 inches). The circuits are so flexible they can be wrapped around objects with diameters as small as 4 mm.

To manufacture flexible circuits with such high trace resolution Metrigraphics employs a mix of proprietary and industry-standard processes. These include high-resolution photolithography as well as sputtered thin-film and plated metal deposition. Multilayer flexible circuits are constructed of several independently stacked, aligned and interconnected layers composed of very thin sputtered metal or thicker-plated metal, such as gold or copper, on polyimide substrates. Plated conductive vias connect the different layers as required. Metrigraphics offers via sizes down to a 25-micron diameter.

The company also offers the latest in thin film circuit manufacturing without the use of chemical etching to define circuit geometry. They use an additive process (aka additive fabrication) in which lines are defined by electroplating or sputtering metal traces onto your choice of rigid substrates (or onto a polyimide layer in a multi-layer device). Chemical etching causes lines to slope, resulting in performance variations and yield issues. By contrast, additive processes ensure vertical walls are the same width at the top as at the bottom so your performance is rigidly consistent circuit after circuit.

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