By Cameron Chai
Baolab Microsystems has developed a CMOS Lorentz force MEMS sensor of high-purity, which ensures that its 3D Digital NanoCompass meets performance standards for power consumption, sensitivity and package size, but at a considerably low cost. Another unique feature is that the equipment auto-calibrates to deliver high accuracy.
The BLBC3-D NanoCompass will be manufactured with the help of the innovative NanoEMS technology from Baolab. NanoEMS allows nanoscale MEMS to be developed with the help of normal high-volume CMOS lines and monolithically integrated with digital and analogue electronics. During the standard CMOS production process, the MEMS elements are outlined within the wafer’s existing layers of metal interconnect.
CEO of Baolab, Dave Doyle, stated that the process of integration of numerous devices into one chip to develop a multi-sensor system with NanoEMS is more cost-effective when compared to traditional MEMS where each sensor is produced using a separate production process.
Baolab’s new design utilizes Lorentz force sensors to identify the magnetic field of the Earth. The MEMS, a flexible aluminium plate attached to springs, is formed from the CMOS chip’s metal interconnect layers by etching the Inter Metal Dielectric (IMD) with the help of vapour HF. The passage of current through the plate results in the generation of a force, which is directly proportional to the Earth’s magnetic field. The resultant displacement is recorded with the help of capacitive detection between the fixed and moveable electrodes, thus detecting the magnetic field intensity in the x, y and z directions using a NanoEMS chip.
Until now, the Lorentz force technique has not been widely used owing to high-manufacturing cost involved in traditional MEMS techniques. However, it is suitable to support the mechanical structures produced using Baolab’s NanoEMS. NanoEMS allows users to manufacture equipment at low cost, thus introducing a new range of mobile devices into the market.