0.4mm×0.4mm barometer sensor-chip fabricated by a scar-free ‘MIS’ (minimally invasive surgery) process for 0.01US$/die product

The paper reports an as tiny as 0.4mm×0.4mm piezoresistive absolute pressure sensor (barometer) for as low-cost as 0.01US$ product, which is widely demanded in smart-phone, drone and consumer-electronic market. The sensor is designed (3D scheme in Fig.2 (a)) and fabricated by a novel scar-free MIS (micro-holes inter-etch & sealing, with the same abbreviation as minimally invasive surgery) MEMS process. This new developed process eliminates the seals from the diaphragm area, thereby achieving good performance of sensitivity=0.98mV/kPa/3.3V and nonlinearity=±0.32%. With the high-yield single-wafer single-side process, ultra-low price of 0.01US$/die is gained thanks to the high throughput of 90000 die per 6-inch wafer.