PORTLAND, Ore. -- The EE Times 2012 Startup of the Year, mCube Inc., just landed a $37 million series C funding round with new investors Keytone Ventures, SK Telecom (China) Ventures, and Korea Investment Partners.
The San Jose, Calif., company is introducing its second generation of inertial sensors -- a 2x2 mm accelerometer, a 1.6x1.6 mm magnetometer, and the 3x3 mm iGyro, which it calls a "soft" gyroscope affordable by any cellphone maker.
"We make the world's smallest MEMS motion sensors," Ben Lee, mCube's president and CEO, told us. "So far, we have shipped over 60 million units, primarily to the greater China market."
The ASIC is first grown on the bottom, then the MEMS mechanical elements are fabricated above and connected with tiny 3 micron vias after which the MEMS element is hermetically sealed with a silicon cap.
In 2011, mCube attracted a $25 million series B round. In 2009, it drew a $10 million series A round led by Kleiner Perkins Caufield & Byers, MediaTek, iD Ventures America, and DAG Ventures. The company will use the $37 series C round to expand beyond the Chinese and Taiwanese handset markets and serve the expanding worldwide market for less expensive smartphones and tablets. It offers three degree-of-freedom (3DoF) accelerometers, 3- and 6-DoF magnetometers, and a 9-DoF soft gyroscope. The iGyro uses sensor fusion on an accelerometer and magnetometer to synthesize the rotational output of a gyro while using 80% less power, costing 50% less, and taking up almost 60% less space than a hardware gyroscope.
"We are in transition from a revenue-based to a growth-based company," Lee said. "We are ready to scale, and with this new infusion of capital, we are also ready to do more R&D to create new sensors for what we call the Internet of Moving Things, which various sources estimate [will include] 25 million devices by 2020."
Gyroscopes are standard equipment in high-end smartphones and tablets, because they add the responsiveness of rotational motion sensing, making gaming a more enjoyable experience, especially on small screens. However, mCube says its soft gyroscope delivers the same immersive 9-DoF motion for gaming and other precision applications like augmented reality by carefully combining a high-precision 3-DoF accelerometer with a highly responsive 6-DoF magnetometer.
"Current gyro solutions are expensive, use proprietary processes, and are discrete, consequently only very high-end smart phones use gyros -- only 10% of the Chinese market. Ninety percent is not being served," Lee said. "What we believe is needed is a new paradigm that is very cost effective, very small, exceptionally low power, and, in the wearable space, must have a battery life of months and be inexpensive enough to be disposable."
mCube says it has the world's smallest three-axis MEMS accelerometer and the only monolithic single-chip version with integrated MEMS and ASIC on the same die. The device is shown here in a 3x3 mm package but is also available in a 2x2 mm package.
The process technology mCube is using to deliver on that promise is a monolithic semiconductor technique that allows it to build the MEMS elements of a design on top of the application specific integrated circuit (ASIC) holding the single-chip electronics. First the ASIC is built using traditional semiconductor techniques. Then the MEMS mechanical elements are assembled on oxide pillars atop the ASIC and hermetically sealed with a silicon cap. In this way, instead of using wire bonds to connect separate MEMS and ASIC chips, or bumps to bond two chips together, mCube can use three-micron vias to interconnect the ASIC and the MEMS elements of a monolithic chip.
Lee said its technique can deliver 14-bit precision at a lower cost than others delivering 12-bit precision -- and on a super-small die, gaining mCube entry into the low-end smartphone, smart watch, and wearable markets, as well as nontraditional markets such as embedding motion sensors into packages to determine when and how its contents were damaged.
— R. Colin Johnson, Advanced Technology Editor, EE Times