A newly-developed 3D printing technique could be used to cost-effectively produce customized electronic machines the size of insects which enable advanced appli­cations in robotics, medical devices and others. The breakthrough could be a potential game-changer for manu­facturing customized chip-based microelectro­mechanical systems (MEMS). These mini-machines are mass-produced in large volumes for hundreds of electronic products, including smartphones and cars, where they provide posi­tioning accuracy. But for more specialized manu­facturing of sensors in smaller volumes, such as accelero­meters for aircraft and vibration sensors for industrial machinery, MEMS technologies demand costly customi­zation.

Frank Niklaus, who led the research at KTH Royal Institute of Technology in Stockholm, says the new 3D printing technique provides a way to get around the limitations of conventional MEMS manu­facturing. “The costs of manufacturing process development and device design optimizations do not scale down for lower production volumes,” he says. The result is engineers are faced with a choice of suboptimal off-the-shelf MEMS devices or economi­cally unviable start-up costs. Other low-volume products that could benefit from the technique include motion and vibration control units for robots and industrial tools, as well as wind turbines.

The researchers built on two-photon polymeri­zation, which can produce high resolution objects as small as few hundreds of nanometers in size, but not capable of sensing func­tionality. To form the transducing elements, the method uses shadow-masking, which works something like a stencil. On the 3D-printed structure they fabricate features with a T-shaped cross-section, which work like umbrellas. They then deposit metal from above, and as a result, the sides of the T-shaped features are not coated with the metal. This means the metal on the top of the T is electri­cally isolated from the rest of the structure. With this method, he says, it takes only few hours to manufacture a dozen or so custom designed MEMS accelero­meters using relatively inexpensive commercial manu­facturing tools.

The method can be used for proto­typing MEMS devices and manu­facturing small- and medium-sized batches of tens of thousands to a few thousand MEMS sensors per year in an economically viable way, he says. “This is something that has not been possible until now, because the start-up costs for manu­facturing a MEMS product using conventional semi­conductor techno­logy are on the order of hundreds of thousands of dollars and the lead times are several months or more,” he says. “The new capabilities offered by 3D-printed MEMS could result in a new paradigm in MEMS and sensor manu­facturing. “Scala­bility isn’t just an advantage in MEMS production, it’s a necessity. This method would enable fabri­cation of many kinds of new, customized devices.” (Source: KTH)

Reference: S. Pagliano et al.: Micro 3D printing of a functional MEMS accelerometer, Microsyst. Nanoeng. 8, 105 (2022); DOI: 10.1038/s41378-022-00440-9

Link: Division of Micro and Nanosystems, KTH Royal Institute of Technology, Stockholm, Sweden