Testing MEMS

mems04How do you test the sensors in smartphones, smartwatches, and up-and-coming medical devices? With a Femtotools FT-RS1002 Microrobotic System of course! In 2016 the Department of Microelectronics and Nanoelectronics (Faculty of ICT, UoM) set up a slew of devices to be able to to probe, prod and poke devices up to a resolution of 1 nm (thinner  than the diameter of a human hair).

Quick Specs

Number of axes: 3

Maximum velocity: 5 mm/s

Minimum motion increment: 1 nm

Actuation principle: Piezoelectric scanning/stepping

Sensor probe tip area: 50 µm x 50 µm

FT-S100000 sensor force range: ±100000 µN

FT-S100000 sensor resolution at 10Hz: ±5 µN

Operating temperature: 5°C to 100°C

The team of computer scientists collaborated with global semiconductor chip maker ST Microelectronics to p roduce MEMS (Micro-Electro-Mechanical Systems). MEMS are the tiny sensors or devices often found in smartphones that allow them to act like a compass, know how fast a person is going, or detect sound. In Malta, the new equipment is being used to measure mechanical properties (for example shear testing and flexure testing) of tiny mirrors that can be used to turn phones into high-quality projectors (part of the Lab4MEMS2 project part-funded by the EU). This toolkit is incredibly versatile, forming part of a station that can have additional add-ons to widen its applications. Now the team wants to buy more sensitive microforce probes and microgrippers that will allo w the manipulation and assembly of microsystems. This toolkit’s micromechanical testing can be used in many research and industrial applications. This way, the horizon is open for studies into semiconductor technology, microsystem development, materials science, micromedicine, or biotechnology—placing Malta on the semiconductor map.

 

Better, cheaper smartphones

MICRo-electro-mechanical systems (MEMS) are about the width of a human hair. They can tell a smartphone which way is ‘up’, enable inkjet printers to eject ink precisely, and are even found in high definition displays. These chips have sensors that detect a physical quantity such as temperature or direction, which is then converted into an electrical signal. The signal can be passed on to a customised computer chip designed for a specific use, called an application-specific integrated circuit (ASIC). A MEMS device operating through an ASIC is called a microsystem, commonly found on handheld devices. Students at the University of Malta are currently researching ways to crucially improve these devices.

Over the past years, research into MEMS has developed sensors for temperature, pressure, inertial forces, chemical properties, magnetic fields, radiation, and more. These tiny microsensors outperformed their larger counterparts at a lower price. Recently, they were adapted for gas and liquid flow control, optical switches, and mirrors found in video projectors.

Locally, the Department of Microelectronics and Nanoelectronics is collaborating with STMicroelectronics, which is funding postgraduate studies in both MEMS and ASIC design. They are investigating accelerometers that, for example, enable a smartphone or a gaming console to know how the device is being held. The Department is using the latest manufacturing techniques to test its research innovations.

Accelerometers have two main functions: sensing direction using an MEMS chip, followed by processing the information using an ASIC. Both chips are placed on a single package. The research focuses on reducing power consumption and cost, which will enable smartphones to perform better at a lower price.

“Training in this field will hopefully entice industry to develop research and design teams focused on this rapidly expanding field,” says Dr Ivan Grech, senior lecturer at the Faculty of ICT. The development of microsystems is an attractive and exciting area of study, which provides new and innovative ways to use smart devices for everyday applications.

 

Research in this area was carried out by Ansel Briffa, Jean Marie Darmanin and Kristian Grixti, as part of their Master of Science in Microelectronics and Nanoelectronics at the Faculty of Information and Communication Technology. They were supervised by Dr Ing. Edward Gatt, Dr Ivan Grech, Dr Ing. Owen Casha and Prof. Ing. Joseph Micallef.