According to Nanusens, its proprietary technology can significantly increase the operational life of earbuds by as much as 20%. This can be achieved by replacing the MEMS sensors in an earbud with a single multi-sensor chip that is up to ten times smaller, freeing up space for larger batteries.
A MEMS (Micro Electro Mechanical Systems) sensor package contains a chip with the MEMS sensor, which is made on the microscopic scale, and a chip with the control electronics resulting in a volume of four cubic millimeters. Nanusens creates its sensors on the nanoscale within the layers of its CMOS chip that also has the control electronics. As a result, the NEMS (Nano Electro Mechanical Systems) chip is only one cubic millimeter so this will create a saving of three cubic millimeters for every MEMS package that it replaces.
X-ray of an earbud showing battery and electronics.
The more MEMS packages are replaced and their functions done by a multi-sensor Nanusens chip, the greater the space savings plus the Nanusens chip only increases slightly with every additional sensor function to accommodate additional control electronics. In addition, far less PCB estate is needed for the tiny, single chip solution compared to the PCB estate required for several MEMS packages. All this freed-up space can be used to increase the size of the battery or add a supercapacitor to extend the battery life to give a better user experience and is of tremendous interest to earbud manufacturers.
Nanusens 2D motion detector
The first product from Nanusens will be a 2D motion detector for earbuds in Q4 2019, which can be used to implement tap and double tap for control, wake-on-movement and sleep-on-rest functions, and, soon after, a 3D accelerometer. A bone conduction sensor for noise cancellation is next to be integrated into the single chip solution. Chips will be available in a small package such as WLCSP or as bare die that can be attached directly to the PCB.
Chip layout showing two Nanusens motion sensors integrated with the control electronics on the same die.
MEMS sensors are created using expensive proprietary processes. Nanusens' multi-patent pending technology enables it to create nano-sensors inside the CMOS layers using standard CMOS processes within the same production flow as the rest of the chip production. This innovative approach reduces the size and cost of the sensors. Nanusens believes that its disruptive technology will revolutionize the sensor market and meet the ever-increasing demand for lower cost sensors in smartphones, wearable technology and IoT devices that has already made sensors a multi-billion-dollar industry as they provide the vital interface between the real world and the electronics.
The nanoscale of this technology means that it has ultra-low power consumption. Importantly for a sensor in a device that is likely to be dropped, the NEMS design is more robust and reliable than MEMS designs. This is because it is less affected by problems of stiction caused Van der Waals or Casimir forces that create reliability issues for MEMS.
Nanusens shrink MEMS to create nano-sensors within the CMOS layers
The Inter Metal Dielectric (IMD) is etched away through the pad openings in the passivation layer using vapor HF (vHF) to create the nano-sensor structures. The holes are then sealed, and the chip packaged as necessary. As only standard CMOS processes with minimal post-processing are used and the sensors can be directly integrated with active circuitry as required, the sensors can potentially have high yields like CMOS devices. This also means that the production is fab-independent.